全文获取类型
收费全文 | 7100篇 |
免费 | 140篇 |
国内免费 | 187篇 |
出版年
2018年 | 21篇 |
2017年 | 27篇 |
2016年 | 26篇 |
2015年 | 37篇 |
2014年 | 29篇 |
2013年 | 35篇 |
2012年 | 578篇 |
2011年 | 618篇 |
2010年 | 157篇 |
2009年 | 106篇 |
2008年 | 480篇 |
2007年 | 499篇 |
2006年 | 459篇 |
2005年 | 407篇 |
2004年 | 371篇 |
2003年 | 298篇 |
2002年 | 297篇 |
2001年 | 188篇 |
2000年 | 227篇 |
1999年 | 81篇 |
1998年 | 53篇 |
1997年 | 23篇 |
1996年 | 41篇 |
1995年 | 23篇 |
1994年 | 76篇 |
1993年 | 87篇 |
1992年 | 92篇 |
1991年 | 97篇 |
1990年 | 92篇 |
1989年 | 93篇 |
1988年 | 104篇 |
1987年 | 119篇 |
1986年 | 86篇 |
1985年 | 114篇 |
1984年 | 110篇 |
1983年 | 133篇 |
1982年 | 84篇 |
1981年 | 83篇 |
1980年 | 74篇 |
1979年 | 78篇 |
1978年 | 63篇 |
1966年 | 48篇 |
1965年 | 131篇 |
1964年 | 104篇 |
1963年 | 127篇 |
1962年 | 54篇 |
1958年 | 76篇 |
1957年 | 59篇 |
1956年 | 44篇 |
1953年 | 9篇 |
排序方式: 共有7427条查询结果,搜索用时 15 毫秒
791.
Ricker C Lagos V Feldman N Hiyama S Fuentes S Kumar V Gonzalez K Palomares M Blazer K Lowstuter K MacDonald D Weitzel J 《Journal of genetic counseling》2006,15(6):505-514
Background: Cancer genetic counseling and testing is a standard of care option for appropriate families and can identify individuals at increased risk prior to diagnosis, when prevention or detection strategies are most effective. Despite documented efficacy of cancer risk reduction in high-risk individuals, underserved and minority individuals have a disproportionate cancer burden and limited access to genetic counseling. Methods: A needs assessment survey documented gaps in knowledge and interest in prevention. Satellite clinics were established at two indigent healthcare systems. Cancer genetics CME lectures were conducted and referral guidelines disseminated to clinicians who referred patients for counseling. Results: An increase in clinician knowledge was demonstrated post-CME and reflected by quality referrals. Eighty-eight percent of patients kept their appointments. In the predominantly Latina6 (n=77) clinic population, 71.4% were affected with cancer, and 17 mutation positive families were identified. Preliminary data shows a positive impact on patients' motivation and behavior. The majority has expressed satisfaction and reduction in anxiety. Conclusions: This study demonstrates feasibility and acceptability of cancer genetics services in this population, suggesting the potential to reduce cancer morbidity in underserved, high-risk families.“Latino” is the most common census term for individuals of Spanish, Mexican, Central and South American, Cuban, or Puerto Rican descent, referring to ethnicity, and is generally considered a more ethnically/culturally based term for individuals of the aforementioned groups. As this cohort is female the feminine noun “Latina” is used 相似文献
792.
Weil J Ormond K Peters J Peters K Biesecker BB LeRoy B 《Journal of genetic counseling》2006,15(2):85-93
Nondirectiveness has been a guiding principle for genetic counseling since the founding of the profession. However, its efficacy and appropriateness in this role have been frequently questioned. A workshop at the 2003 Annual Education Conference of the National Society of Genetic Counselors provided audience participation in a discussion of these issues. Participants presented arguments for and against nondirectiveness as a central ethos. They described complex personal transitions in adapting what they had learned about nondirectiveness during training to the realities of the workplace. There was support for flexible approaches to genetic counseling, with varying adherence to nondirectiveness, based on client and family needs and values, clinical circumstances, and desired counseling outcomes. The discussion supports the use of clinical experience, outcomes research, and the experience of other professions to move beyond nondirectiveness and more accurately identify the theoretical bases that underlie genetic counseling in the variety of circumstances in which it is currently practiced. 相似文献
793.
Extinction of conditioned taste aversion depends on functional protein synthesis but not on NMDA receptor activation in the ventromedial prefrontal cortex 下载免费PDF全文
Akirav I Khatsrinov V Vouimba RM Merhav M Ferreira G Rosenblum K Maroun M 《Learning & memory (Cold Spring Harbor, N.Y.)》2006,13(3):254-258
We investigated the role of the ventromedial prefrontal cortex (vmPFC) in extinction of conditioned taste aversion (CTA) by microinfusing a protein synthesis inhibitor or N-methyl-d-asparate (NMDA) receptors antagonist into the vmPFC immediately following a non-reinforced extinction session. We found that the protein synthesis blocker anisomycin, but not the NMDA receptors antagonist D,L-2-amino-5-phosphonovaleric acid, impaired CTA extinction in the vmPFC. Anisomycin microinfusion into vmPFC had no effect on CTA acquisition and by itself did not induce CTA. These findings show the necessary role functional protein synthesis is playing in the vmPFC during the learning of CTA extinction. 相似文献
794.
Our reduced ability to correctly report two sequentially presented targets is seen in the robust effect known as the attentional
blink (AB; Raymond, Shapiro, & Arnell, 1992). One recent report (Olivers & Nieuwenhuis, 2005) strikingly reveals the AB to
be virtually abolished when non-task-demanding music occurs in the background. The authors suggest that a diffuse attentional
state is the mediating factor. Here, we seek to broaden the finding’s generality by determining if task-irrelevant visual
motion and flicker also attenuate the AB. In our experiments, the AB task was presented together with a background field of
moving dots that could moveaway from ortoward the central AB task, or flicker. In the control condition, the dots remained static. The AB was attenuated—though to different
degrees—in all experimental conditions, but not in the static condition. Our findings add to the generality of the previous
conclusions, and we emphasize an account based on the overallocation of attention. 相似文献
795.
Agreement between adolescents, mothers, fathers, and teachers on adolescents' personality traits was investigated in a longitudinal study. The targets for personality ratings were the adolescents who participated in the European Youth Heart Study in Estonia. There were 593 participants in the first wave and 480 participants in the follow-up study 3 years later. Adolescents' self-reports as well as father, mother, and teacher ratings were collected using questionnaires to measure the five-factor model of personality. In both waves, inter-rater agreement was highest between mothers and fathers, was low to moderate for parent-self ratings, and was lowest for ratings between self and teacher, mother and teacher, and father and teacher. Test-retest correlations were moderate for parent and self-ratings but failed to reach statistical significance for three of the five teacher-rated traits, suggesting lower reliability of teacher ratings. Possible explanations for the low agreement between teachers and other judges are discussed. 相似文献
796.
Shionoya K Moriceau S Lunday L Miner C Roth TL Sullivan RM 《Learning & memory (Cold Spring Harbor, N.Y.)》2006,13(6):801-808
Fetal and infant rats can learn to avoid odors paired with illness before development of brain areas supporting this learning in adults, suggesting an alternate learning circuit. Here we begin to document the transition from the infant to adult neural circuit underlying odor-malaise avoidance learning using LiCl (0.3 M; 1% of body weight, ip) and a 30-min peppermint-odor exposure. Conditioning groups included: Paired odor-LiCl, Paired odor-LiCl-Nursing, LiCl, and odor-saline. Results showed that Paired LiCl-odor conditioning induced a learned odor aversion in postnatal day (PN) 7, 12, and 23 pups. Odor-LiCl Paired Nursing induced a learned odor preference in PN7 and PN12 pups but blocked learning in PN23 pups. 14C 2-deoxyglucose (2-DG) autoradiography indicated enhanced olfactory bulb activity in PN7 and PN12 pups with odor preference and avoidance learning. The odor aversion in weanling aged (PN23) pups resulted in enhanced amygdala activity in Paired odor-LiCl pups, but not if they were nursing. Thus, the neural circuit supporting malaise-induced aversions changes over development, indicating that similar infant and adult-learned behaviors may have distinct neural circuits. 相似文献
797.
The authors examined measurement bias in the Hogan Personality Inventory by investigating differential item functioning (DIF) across sex and two racial groups (Caucasian and Black). The sample consisted of 1,579 Caucasians (1,023 men, 556 women) and 523 Blacks (321 men, 202 women) who were applying for entry-level, unskilled jobs in factories. Although the group mean differences were trivial, more than a third of the items showed DIF by sex (38.4%) and by race (37.3%). A content analysis of potentially biased items indicated that the themes of items displaying DIF were slightly more cohesive for sex than for race. The authors discuss possible explanations for differing clustering tendencies of items displaying DIF and some practical and theoretical implications of DIF in the development and interpretation of personality inventories. 相似文献
798.
Pass K Green NS Lorey F Sherwin J Comeau AM 《Mental retardation and developmental disabilities research reviews》2006,12(4):293-300
The term "pilot study" has been used over the years to describe the evaluation of the many elements involved in deciding whether a proposed condition should be added to a newborn screening (NBS) panel, and until recently, was unilaterally used to describe the evaluation of the assay to be used before the condition was officially adopted by a state for its newborn screening panel. Since Guthrie's introduction of screening for PKU, each time a new condition was added to the panel, the screening assay itself was validated through a population-based trial, in which the test was performed with de-identified samples to avoid association between the test result and the infant. This is considered by the laboratory as the "pilot phase" of adding a new condition. To advance the science of NBS, especially to accommodate new technologies that may provide new types of information (genetic versus physiological) for each new condition, pilot programs are essential. Involvement of the clinical community serves to improve these evaluations and provides the needed clinical validation of decisions made as a result of it. This paper describes the historical context of pilot programs in population-based NBS that utilize laboratory-based markers as indicators of concern; specifically, three applications that demonstrate different approaches to the use of pilots in adding conditions to a NBS panel are described. 相似文献
799.
800.
Perrino T Fernández MI Bowen GS Arheart K 《Cultural diversity & ethnic minority psychology》2006,12(1):70-83
In this cross-sectional study the authors examine condom use attempts and condom use among 305 high-risk, low-income African American women who reported having a main partner. Women who had recently attempted to convince their main partner to use condoms were almost 10 times more likely to have recently used condoms with their partner than women who had not made an attempt. Among the subsample of 116 women who had recently made a condom use attempt with their main partner, having a history of childhood abuse and having one's main partner raise infidelity questions in response to the condom use attempt were negatively associated with recent condom use with this partner. Findings provide initial insights into the importance of women's condom use attempts, as well as subgroups of women who may encounter special challenges convincing their main partner to use condoms. 相似文献