首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4571篇
  免费   716篇
  国内免费   344篇
  2024年   31篇
  2023年   189篇
  2022年   115篇
  2021年   123篇
  2020年   274篇
  2019年   265篇
  2018年   302篇
  2017年   280篇
  2016年   289篇
  2015年   172篇
  2014年   188篇
  2013年   831篇
  2012年   137篇
  2011年   124篇
  2010年   95篇
  2009年   159篇
  2008年   176篇
  2007年   205篇
  2006年   220篇
  2005年   208篇
  2004年   149篇
  2003年   130篇
  2002年   129篇
  2001年   104篇
  2000年   96篇
  1999年   81篇
  1998年   53篇
  1997年   72篇
  1996年   54篇
  1995年   46篇
  1994年   50篇
  1993年   38篇
  1992年   34篇
  1991年   22篇
  1990年   12篇
  1989年   18篇
  1988年   14篇
  1987年   13篇
  1986年   6篇
  1985年   12篇
  1984年   16篇
  1983年   9篇
  1982年   17篇
  1981年   6篇
  1980年   11篇
  1979年   19篇
  1978年   11篇
  1977年   11篇
  1976年   6篇
  1975年   9篇
排序方式: 共有5631条查询结果,搜索用时 15 毫秒
101.
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   
102.
Despite advances in behavioral medicine and health psychology, the health care system and medical education continue to show resistance to a truly biopsychosocial model of medical practice. Psychologists in medical settings have generally been identified as challenging the concept of mind-body duality and the segregation of biologic and psychosocial sciences in medicine. However, examples are presented of how psychologists contribute to and perpetuate mind-body segregation via exclusive theoretical conceptualizations, arbitrary definitions of professional behavior, and dogmatic constraints on the limits of psychology's field of knowledge.  相似文献   
103.
This study investigated the prevalence of traumatic brain injury (TBI) in an inpatient psychiatric population. We hypothesized increased prevalence of TBI relative to the general population due to a variety of risk factors observed in psychiatric patients. One hundred (mean age = 34) psychiatric inpatients completed the revised Head Injury Questionnaire. Chart review of 17 subjects reporting injuries established whether injuries were documented in medical records. Sixty-eight percent of this psychiatric population reported one or more injuries in which they were unconscious or dazed. This number is higher than the prevalence in the general population. Injuries were generally of mild to moderate severity; multiple injuries were common. Chart review of 17 subjects reporting TBI indicated that histories of TBI had not been noted in the medical record. Finally, 63% of TBI subjects reported that their injury predated the onset of their psychiatric symptoms. These results suggest a possible role of TBI in psychiatric symptomatology and have implications for psychiatric treatment in this population.  相似文献   
104.
The results of an earlier study (Olsho, 1984) indicated that 5- to 8-month-old infants were relatively better at discriminating among high-frequency pitches than low. In the present study, sensory and nonsensory explanations for that effect were evaluated by examining infants' performance in a task requiring similar sensory processing but differing in the demands placed on processes such as memory. Infants' ability to resolve frequency was tested using a tonal masking paradigm, the psychophysical tuning curve. Twenty-four infants were tested at probe frequencies ranging from 500 to 4000 Hz; a group of young adults served as a comparison. Masked and unmasked thresholds were estimated using the visually reinforced head turn procedure in conjunction with an adaptive psychophysical method. Although infants' tuning curves fell below those of adults (indicating poorer performance), the widths and slopes of the infants' curves were not different from the adults'. Moreover, the difference between age groups remained constant across probe frequencies. These findings imply that by 5 months of age, the infant's ability to resolve sound frequency is similar to the adult's.  相似文献   
105.
Two experiments were conducted to compare the effects of several prompting and reinforcement procedures on the participation of elderly citizens in a nutritious meal program. Experiment I employed a variation of the multiple-baseline design across three groups of approximately 60 households each. Elderly persons not previously participating in the program were introduced to the following conditions: (1) public service radio announcements for four weeks to advertise the meal program and the availability of free transportation, (2) a home visit that served as a personal invitation and a second prompt for participation, (3) a followup telephone call, and (4) an incentive menu for participation, which was sent through the mail. Results indicated that the home visits and incentives were both effective as recruitment procedures and superior to other conditions; however, incentives proved to be the most cost-effective intervention. Experiment II used a variation of the multi-element design to compare the effects of scheduled activities and incentives in maintaining higher levels of participation by those persons who had attended the meal program at least once in the past, but whose current rate of participation was low. Results showed that activities improved attendance levels somewhat and that incentives substantially increased the number of meal program participants. Data from these experiments thus indicate that relatively inexpensive procedures may be used effectively to increase the extent to which elderly persons make use of potentially beneficial community-based services.  相似文献   
106.
Reaction times of pigeons on a wavelength discrimination task   总被引:5,自引:5,他引:0       下载免费PDF全文
After extensive pretraining, three pigeons were exposed in 2-second trials to a random series of 14 light wavelengths, ranging in one nanometer (nm) steps from 575 nanometers to 589 nanometers. Responses to one of the wavelengths, 582 nanometers, were intermittently reinforced. The relative frequency of response approached 1.0 at 582 nanometers, and decreased with progressively higher and lower wavelengths. Reaction times shorter than about 0.2 second occurred with a low frequency that was largely independent of wavelength. Wavelength controlled the frequency of longer reaction times, but did not affect the distribution of these reaction times. Consequently, receiver-operating characteristic curves constructed by using reaction time as a rating measure did not conform to the signal-detection model, in contrast to such conformity when response rate is used in a similar way. The data suggest that stimulus onset as such triggers early response emission with some small probability; the probability of responses with longer latency is controlled by wavelength, but their time of emission is controlled by some independent process.  相似文献   
107.
In the last several years, various organizations have produced strikingly similar documents by which institutions for retarded persons are judged for licensure. The purpose of the present study was to determine whether residential units that were licensed differed from residential units that were not licensed in terms of the active programming behaviors of their staff and residents. Data were collected through a time-sampling procedure that yielded about 160,000 observations on eight staff and six resident behaviors. Results showed that the licensed units were just as derelict as unlicensed units in providing habilitative programming for their retarded residents. Maladaptive responding by residents occurred at least as much as task-related behaviors: residents spent as much time self-stimulating as they did in programming; they also engaged in self-abusive behavior about as much time as they engaged in on-task responding. Results were discussed in terms of the failure of governmental regulations that are not based on observation to adequately assess habilitative programming.  相似文献   
108.
The Comprehensive Ability Battery (CAB) was used to assess 18 primary mental abilities in 53 white, male prison inmates for whom highly reliable ratings of psychopathy were available. None of the correlations between ratings of psychopathy and scores on the CAB tests was significant, and the overall pattern or structure of abilities was the same for inmates with low and high ratings of psychopathy. The possibility is raised that the personality characteristics of psychopaths make them appear to be brighter and more creative than they actually are. Compared with norms for male high school students, the inmates as a group generally performed well, falling near the 50th percentile on 11 of the tests. The inmates performed significantly better than the normative sample on tests of verbal ability, esthetic judgment, aiming, and representational drawing, and significantly worse on tests of ideational fluency, spontaneous flexibility, and word fluency.This research was supported by Grant MT-4511 from the Medical Research Council of Canada.  相似文献   
109.
Two experiments were conducted using an autoshaping procedure with pigeons to examine whether dimensional stimulus control by a Pavlovian facilitator parallels the control established following operant discrimination training. Facilitation training consisted of the presentation of a black vertical line on a white background as the B stimulus in a feature-positive discrimination in which the A stimulus (white keylight) was followed by grain presentation only if preceded by B. In this way, B facilitates or sets the occasion for pecking at A. Subsequent testing for generalization along the line-orientation dimension produced decremental gradients when the facilitation paradigm incorporated an explicit feature-negative stimulus (B−). These results parallel the decremental control obtained following operant discrimination training and suggest that Pavlovian facilitators and instrumental discriminative stimuli are functionally equivalent.  相似文献   
110.
A subject's performance under a conditional-discrimination procedure defines conditional relations between stimuli: “If A1, then B1; if A2, then B2.” The procedure may also generate matching to sample. If so, the stimuli will be related not only by conditionality, but by equivalence: A1 and B1 will become equivalent members of one stimulus class, A2 and B2 of another. One paradigm for testing whether a conditional-discrimination procedure has generated equivalence relations uses three sets of stimuli, A, B, and C, three stimuli per set. Subjects learn to select Set-B and Set-C comparisons conditionally upon Set-A samples. Having been explicitly taught six sample-comparison relations, A1B1, A1C1, A2B2, A2C2, A3B3, and A3C3, subjects prove immediately capable of matching the B- and C-stimuli; six new relations emerge (B1C1, B2C2, B3C3, C1B1, C2B2, C3B3). The 12 stimulus relations, six taught and six emergent, define the existence of three three-member stimulus classes, A1B1C1, A2B2C2, and A3B3C3. This paradigm was expanded by introducing three more stimuli (Set D), and teaching eight children not only the AB and AC relations but DC relations also—selecting Set-C comparisons conditionally upon Set-D samples. Six of the children proved immediately capable of matching the B- and D-stimuli to each other. By selecting appropriate Set-B comparisons conditionally upon Set-D samples, and Set-D comparisons conditionally upon Set-B samples, they demonstrated the existence of three four-member stimulus classes, A1B1C1D1, A2B2C2D2, and A3B3C3D3. These larger classes were confirmed by the subjects' success with the prerequisite lower-level conditional relations; they were also able to select Set-D comparisons conditionally upon samples from Sets A and C, and to do the BC and CB matching that defined the original three-member classes. Adding the three DC relations therefore generated 12 more, three each in BD, DB, AD, and CD. Enlarging each class by one member brought about a disproportionate increase in the number of emergent relations. Ancillary oral naming tests suggested that the subject's application of the same name to each stimulus was neither necessary nor sufficient to establish classes of equivalent stimuli.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号