全文获取类型
收费全文 | 49286篇 |
免费 | 1155篇 |
国内免费 | 12篇 |
专业分类
50453篇 |
出版年
2019年 | 393篇 |
2018年 | 3886篇 |
2017年 | 3258篇 |
2016年 | 2794篇 |
2015年 | 648篇 |
2014年 | 609篇 |
2013年 | 2659篇 |
2012年 | 1445篇 |
2011年 | 3249篇 |
2010年 | 3019篇 |
2009年 | 1989篇 |
2008年 | 2439篇 |
2007年 | 2908篇 |
2006年 | 742篇 |
2005年 | 889篇 |
2004年 | 824篇 |
2003年 | 739篇 |
2002年 | 759篇 |
2001年 | 866篇 |
2000年 | 853篇 |
1999年 | 669篇 |
1998年 | 364篇 |
1997年 | 328篇 |
1996年 | 330篇 |
1995年 | 321篇 |
1992年 | 549篇 |
1991年 | 535篇 |
1990年 | 514篇 |
1989年 | 475篇 |
1988年 | 478篇 |
1987年 | 437篇 |
1986年 | 454篇 |
1985年 | 465篇 |
1984年 | 407篇 |
1983年 | 387篇 |
1982年 | 307篇 |
1981年 | 341篇 |
1979年 | 467篇 |
1978年 | 372篇 |
1977年 | 325篇 |
1975年 | 371篇 |
1974年 | 452篇 |
1973年 | 430篇 |
1972年 | 344篇 |
1971年 | 324篇 |
1970年 | 312篇 |
1969年 | 306篇 |
1968年 | 391篇 |
1967年 | 339篇 |
1966年 | 319篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
In January 1996, the American Board of Genetic Counseling (ABGC) adopted 27 practice-based competencies as a standard for assessing the training of graduate students in genetic counseling. These competencies were identified and refined through a collective, narrative process that took place from January through November 1994, and included directors of graduate programs in genetic counseling, ABGC board members and expert consultants. These competencies now form the basis of the document Requirements for Graduate Programs in Genetic Counseling Seeking Accreditation by the American Board of Genetic Counseling (American Board of Genetic Counseling, 1996). The competencies are organized into four domains and are presented and discussed in this article.The Consortium includes Directors of established graduate programs in genetic counseling and members of the ABGC Board of Directors who participated in the Consensus Development Conference held in January, 1994: Diane Baker (University of Michigan/ABGC); Bonnie Baty (ABGC); Joan Burns (University of Wisconsin); Debra Collins (ABGC); Virginia Corson (ABGC); Beth Fine (Northwestern University/ABGC); Elizabeth Gettig (University of Pittsburgh); Verle Headings (Howard University); Jacqueline Hecht (University of Texas); Carl Huether (University of Cincinnati); Bonnie LeRoy (University of Minnesota); Joan Marks (Sarah Lawrence College); Anne Matthews (University of Colorado); Roberta Palmour (McGill University); Lorna Phelps (Medical College of Virginia); Kimberly Quaid (Indiana University); Joan Scott (ABGC); Ann Smith (ABGC); Helen Travers (ABGC); Judith Tsipis (Brandeis University); Ann Walker (University of California-Irvine/ABGC); Jon Weil (University of California-Berkeley); S. Robert Young (University of South Carolina); Randi Zinberg (Mount Sinai School of Medicine, New York). 相似文献
982.
Michael H. Mesches Marino Bianchin James L. McGaugh 《Neurobiology of learning and memory》1996,66(3):324-340
The aim of these experiments was to determine whether impaired retention performance in aversively motivated tasks, induced by blockade of amygdala AMPA receptors, is due to influences on mechanisms underlying memory retrieval or to other influences on performance. Rats received either footshock escape training (1 or 10 trials), or no foot shock, in a two-compartment straight alley and bilateral intra-amygdala infusions of the AMPA receptor antagonist CNQX (0.5 μg) were subsequently administered prior to inhibitory avoidance retention testing 8 days later. The CNQX impaired, but did not block, inhibitory avoidance retention performance as indicated by the initial latencies to enter the shock compartment. The animals were then retained in the alley until they remained in the starting compartment for 100 consecutive s and entries into the shock compartment were recorded as errors. In both the controls and CNQX-treated groups, increases in amount of original training resulted in fewer errors, indicating memory for the escape training. Furthermore, regardless of the amount of original training (i.e., 0, 1, or 10 trials), CNQX-treated groups made more errors. Other experiments examined intra-amygdala CNQX effects on reactivity to footshock, locomotor activity, and anxiety. CNQX decreased reactivity to footshock, blocked shock-induced decreases in locomotor activity, and had an anxiolytic effect in an elevated plus maze comparable to that induced by midazolam (0.5 μg). These findings suggest that intra-amygdala infusions of CNQX prior to retention testing affect inhibitory avoidance retention performance following aversive training by altering locomotor activity, reducing sensitivity to footshock, and reducing anxiety. The implications of these findings for hypotheses concerning amygdala function in aversively motivated learning and memory is discussed. 相似文献
983.
The American Board of Genetic Counseling (ABGC) sponsored a consensus development conference with participation from directors of graduate programs in genetic counseling, board members, and expert consultants. Using a collective, narrative, and case-based approach, 27 competencies were identified as embedded in the practice of genetic counseling. These competencies were organized into four domains of skills: Communication; Critical Thinking; Interpersonal, Counseling, and Psychosocial Assessment; and Professional Ethics and Values. The adoption of a competency framework for accreditation has a variety of implications for curriculum design and implementation. We report here the process by which a set of practice-based genetic counseling competencies have been derived; and in an accompanying article, the competencies themselves are provided. We also discuss the application of the competencies to graduate program accreditation as well as some of the implications competency-based standards may have for education and the genetic counseling profession. These guidelines may also serve as a basis for the continuing education of practicing genetic counselors and a performance evaluation tool in the workplace.The Consortium includes Directors of established graduate programs in genetic counseling and members of the ABGC Board of Directors who participated in the Consensus Development Conference held in January 1994: Diane Baker (University of Michigan/ABGC); Bonnie Baty (ABGC); Joan Burns (University of Wisconsin); Debra Collins (ABGC); Virginia Corson (ABGC); Beth Fine (Northwestern University/ABGC); Elizabeth Gettig (University of Pittsburgh); Verle Headings (Howard University); Jacqueline Hecht (University of Texas); Carl Huether (University of Cincinnati); Bonnie LeRoy (University of Minnesota); Joan Marks (Sarah Lawrence College); Anne Matthews (University of Colorado); Roberta Palmour (McGill University); Lorna Phelps (Medical College of Virginia); Kimberly Quaid (Indiana University); Joan Scott (ABGC); Ann Smith (ABGC); Helen Travers (ABGC); Judith Tsipis (Brandeis University); Ann Walker (University of California-Irvine/ABGC); Jon Weil (University of California-Berkeley); S. Robert Young (University of South Carolina); Randi Zinberg (Mount Sinai School of Medicine, New York). 相似文献
984.
Nicola K. Caldwell B.S. Mark Wolery Ph.D. Margaret G. Werts Ed.S. Yvonne Caldwell M.S. 《Journal of Behavioral Education》1996,6(4):459-480
The effects of embedding a constant time delay procedure into an independent seat work activity and using instructive feedback were evaluated in this study. Seven students with mild disabilities participated in the study that occurred in their special education classroom. A multiple probe design across sets of target behaviors was used, and students' responses to instructive feedback stimuli were evaluated during each probe condition. The procedures were implemented with a high degree of fidelity, and the results indicate that (a) the students acquired the target behaviors taught with the constant time delay procedure that was embedded into independent seat work, and (b) the students acquired some but not all of the responses to the instructive feedback stimuli. These findings are discussed in terms of using instructive feedback in classrooms and future research on instructive feedback. 相似文献
985.
C. L. M. Carnrike Jr. Lance M. McCracken James E. Aikens 《Journal of clinical psychology in medical settings》1996,3(1):57-67
Some aspect of psychosocial criteria is commonly utilized by most transplant programs in assessing candidates' acceptability for transplantation. However, regardless of the assessment methodology, information obtained in pretransplant assessments may be limited given the evaluative nature of the assessment as well as the sensitive nature of the contents. Indeed, transplant candidates may present themselves in a favorable fashion, minimizing any negative traits or psychological dysfunction which they perceive might prevent transplantation. Unfortunately, there are limited data addressing the extent to which transplant candidates may present themselves in an overly positive light. This investigation surveys the prevalence of social desirability in lung transplant candidates as well as its association with self-reports of perceived stress. Further, the relationship between social desirability and interviewer ratings of transplant candidacy is examined. Subjects included 24 patients in end-stage organ failure being evaluated for lung transplant candidacy. Subjects completed the Perceived Stress Scale and a brief version of the Marlowe-Crowne Social Desirability Scale. Additionally, subjects were interviewer-rated on the Psychosocial Assessment of Candidates for Transplantation. Results indicate social desirability is a prevalent phenomenon in lung transplant candidates, with more than half of the sample scoring at or above the 84th percentile on the social desirability measure. Further, self-reports of perceived stress are moderately and inversely associated with social desirability (r=–.55,p .01). Social desirability was unrelated to interviewer-ratings of transplant candidates acceptability (r=.13,p .56). Future research might include larger samples of subjects, other organ transplant candidates, and more detailed assessments of symptom distress. 相似文献
986.
We investigated offense characteristics for a national sample of 38,749 homicide arrestees identified in the FBI Supplemental Homicide Reports for 1984 and 1993. Analyses indicated little change from 1984 to 1993 in the circumstances of homicides committed by adolescent girls; however, there were consistent offense differences between girls and boys, and between girls and women. Homicides by adolescent girls were more likely than those committed by boys to involve interpersonal conflict rather than a criminal motive such as robbery. Girls were more likely than boys to use a knife rather than a firearm and their victims were more likely to be under the age of 13 years. Compared to women (18 years or older), girls were more likely to act with an accomplice and their victims were more likely to be female and between 13 and 20 years of age. Results were inconsistent with a stereotypic masculinization theory of the increase in female violence, but provide indirect support for the importance of domestic stress and relational conflict experienced by adolescent girls. Overall, this study supports the need for differentiated study of violence by juvenile girls, and for preventive interventions which target domestic and interpersonal stress. 相似文献
987.
Mary E. Evans Ph.D. Mary I. Armstrong M.S.W. M.B.A. Anne D. Kuppinger M.Ed. 《Journal of child and family studies》1996,5(1):55-65
New York State's initial attempt at individualizing services occurred within the context of an experiment. We randomly assigned children 5–12 years old who were referred for out-of-home placement in treatment foster care to either treatment foster care, Family-Based Treatment (n=15), or to Family-Centered Intensive Case Management (FCICM) (n=27). FCICM used teams of case managers and parent advocates to provide in-home services. Flexible service dollars, respite care, and behavior management skills training were available to assist teams in individualizing care. Preliminary outcomes indicate that children in FCICM are doing as well or better than children assigned to FBT in their functioning and symptom reduction. Parents of children in FCICM have made gains, although not at a statistically significant level, in behavior management skills and family strengths that allow them to provide care for their children at home. 相似文献
988.
Victor J. Perotti James T. Todd J. Farley Norman 《Attention, perception & psychophysics》1996,58(5):666-679
Four experiments investigated observers’ judgments of rigidity for different types of optical motion. The depicted structural deformations were of two types: (1) those with nonparallel image trajectories that are detectable from the first-order spatiotemporal relations between pairs of views; and (2) those with parallel image trajectories that can only be detected from higher order relations among three or more views. Patterns were composed of smooth flow fields in Experiments 1 and 3, and of wire frame figures in Experiments 2 and 4. For both types of display, the nonrigidity detectable from the first-order spatiotemporal structure of the motion sequence was much more salient than the deformation detectable only from the higher order spatiotemporal structure. These results indicate that observers’ judgments of rigidity are based primarily on a two-view analysis, but that some useful information can be obtained under appropriate circumstances from higher order spatiotemporal relations among three or more views. 相似文献
989.
Long-term retention of fixed-interval curvature as an index of recall memory which is relatively free of retrieval cues was examined in younger and older rats. Previous research on free-operant behavior in younger and older rats showing within-session decrements in behavior of older rats and within-session increments in younger rats suggested that the results of recall memory tests would depend upon the duration of the test session and the point within the session where data were collected. Consistent with such expectations, recall of fixed-interval curvature was poorer in older rats when data from late in the test session or data averaged over the entire 45-min session were used, but the opposite finding, numerically better retention in the older rats, occurred when data from the earliest part of the test session were used. The results suggest that age-related performance differences from which age-related memory differences are inferred may be confounded by other age-related effects upon performance which have nothing to do with memory. 相似文献
990.