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   11066篇
  免费   506篇
  国内免费   4篇
  2023年   92篇
  2022年   72篇
  2021年   159篇
  2020年   220篇
  2019年   247篇
  2018年   348篇
  2017年   331篇
  2016年   399篇
  2015年   295篇
  2014年   320篇
  2013年   1128篇
  2012年   586篇
  2011年   598篇
  2010年   358篇
  2009年   327篇
  2008年   476篇
  2007年   477篇
  2006年   377篇
  2005年   432篇
  2004年   399篇
  2003年   377篇
  2002年   347篇
  2001年   192篇
  2000年   154篇
  1999年   162篇
  1998年   140篇
  1997年   128篇
  1996年   115篇
  1995年   102篇
  1994年   87篇
  1993年   106篇
  1992年   114篇
  1991年   112篇
  1990年   105篇
  1989年   69篇
  1988年   76篇
  1987年   79篇
  1986年   85篇
  1985年   91篇
  1984年   90篇
  1983年   91篇
  1982年   73篇
  1981年   80篇
  1980年   76篇
  1979年   77篇
  1978年   83篇
  1977年   84篇
  1976年   71篇
  1975年   62篇
  1974年   73篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Young normals, elderly normals, and patients with either mild-to-moderate or severe senile dementia of the Alzheimer type (SDAT) were administered several tests of language function and remote memory. On all of the language tests examined, elderly normals exhibited a mild, nonsignificant performance decrement relative to the young normals. Advanced SDAT patients were markedly impaired on all of the tests. Early dementia patients were most impaired, relative to aged normals, on tests of object naming, category instance fluency, and remote memory. The deficit was smaller on the WAIS vocabulary subtest, on selecting the name of a visually presented object, and on recalling the function of an object. Early SDAT patients were least impaired in selecting the picture of an object after its name had been provided and in selecting objects that belong to a specified functional category. The results are consistent with the notion that the language dysfunction in early SDAT is due to a deficit in semantic memory function in which general, categorical information remains available whereas information about specific attributes becomes less accessible. The object naming test might be useful in the assessment of treatment effects upon SDAT because of its sensitivity and specificity to dementia, its high face validity, and its independence of recent memory.  相似文献   
72.
At the work site, smoking accounts for increased health care expenses and worker absenteeism due to smoking-related illness and reduced productivity and lost wages. Developing comprehensive and accessible smoking cessation programs at the work site is an important objective for health care professionals. In this study, employees of 43 corporations participated in a televised smoking cessation program accompanied by self-help manuals. The media component involved presenting a smoking cessation program on a network television affiliate station during the 4:30 p.m. and 10:00 p.m. news for 20 days. Employees at half the corporations also had access to semiweekly self-help group meetings. Adding self-help support groups to a program involving self-help manuals and the media reports was found to significantly increase abstinence and its maintenance over time. The implications of using the media, self-help groups, and work site locations in large-scale community-based interventions are discussed.  相似文献   
73.
Regional cerebral blood flow (rCBF) may be measured with inhalation techniques that use end-expired values of radioactivity to estimate the isotope concentration in arterial blood. These end-expired data are used as an input function in a mathematical equation to derive rCBF. End-expired air is assumed normally to be in equilibrium with the arterial blood at the alveolar surface of the lung during regular (passive) breathing; this assumption may not be valid during continuous phonation. We therefore have analyzed breathing (inhalation/exhalation) patterns and end-expired radioactivity (133Xe) during (1) speaking, (2) singing, and (3) humming of the national anthem, and also during (4) passive breathing. Statistically significant differences in breathing patterns were measured between a group of nonmusicians and two groups of musicians (singers) during the phonation tasks: The nonmusicians breathed more often (and more rapidly) and exhibited less variability in their breathing patterns than did the musicians. Notwithstanding these differences, the shapes of smoothed functions derived from the end-expired values were not influenced appreciably during phonation (except possibly during talking). The latter finding suggests that estimates of rCBF derived with these data should not be confounded seriously because of the continuous phonation.  相似文献   
74.
The influence of sexual experience on preference behavior was investigated in adult female rats. In the first experiment, preference behavior for sexually active males versus estrous females was investigated in female rats who were experienced with mounting behavior. Preference of these mount experienced females was compared to preference of females who were naive in this respect. Mount experience with estrous females induced a female-directed preference in ovariectomized female rats, irrespective of whether the females were treated with OIL or with testosterone-propionate (500 micrograms TP, injected once 48 h prior to testing). Sexually naive, OIL-treated females did not show a preference for males or females, but TP induced a preference for a male. Individual differences in mount frequency were not correlated with preference behavior. In the second experiment, the influence of experience with feminine sexual responses on preference behavior was investigated. OIL-treated and TP-treated females oriented equally toward males and females when they had been given the opportunity to copulate with males prior to the preference tests. The results strongly suggest that prior sexual experience is an important determinant of preference behavior. The female's behavior during sexual interactions was, however, not predictive of later preference.  相似文献   
75.
Several theories have been presented that predict differences between women and men in attitudes toward the environment due to differences in sex roles. Research on which these theories can be tested has tended to examine general environmental concern, and the results have generally been weak and inconclusive. Using an approach suggested in the literature, this study examines sex differences in concern and knowledge, using multi-item scales for each, about one environmental issue — acid rain. The results contradict the theories being tested, however: if there is a sex difference, men are found to be more concerned and knowledgeable about the environmental problem.  相似文献   
76.
77.
A major home improvement chain located primarily in the western United States initiated the use of thePersonnel Selection Inventory, a written integrity test, as part of its pre-employment hiring process. For two years only, those job applicants who passed this test and other pre-employment criteria were hired by the chain. Following the introduction of the inventory, there was: (1) a 50% reduction in the number of employee terminations for theft, illegal drug use, and violence over a five year period and (2) a savings in shrinkage losses that amounted to over two million dollars over a two year period.  相似文献   
78.
The influence of alcohol and loud music on analytic versus holistic processing was examined in classification, concept learning, and embedded figures tasks. In the classification task, loud music reduced analytic responding by individuals who had consumed alcohol and increased analytic responding by individuals who had received placebo drinks. Alcohol also decreased the speed with which individuals were able to generate analytic responses in the classification task and decreased analytic performance on the embedded figures test. Alcohol slowed the rate of learning in the concept-learning task but did not lead to less analytic responding in that task. The results are consistent with the idea that alcohol slows the rate of information processing, particularly in tasks requiring visual analysis of stimuli.  相似文献   
79.
The psychophysiological responses of heart rate (HR), systolic and diastolic blood pressure, skin conductance level and forehead electromyogram were compared during: rest, mental arithmetic and combat sounds of gradually increasing intensity for five groups of Ss: Vietnam veterans with post-traumatic stress disorder (PTSD); Vietnam veterans without PTSD but with comparable levels of combat experience; Vietnam veterans with other psychiatric disorders; Vietnam-era veterans; and nonveteran phobics. HR response to low-intensity combat sounds provided good discrimination between veterans with PTSD and the other groups and seems to resemble a conditioned emotional response.  相似文献   
80.
Recognizing people seen in events via dynamic "mug shots"   总被引:1,自引:0,他引:1  
This study examined effects of an event and dynamic mug shots on facial recognition. Witnesses saw either a film of a liquor store holdup staged by six perpetrators, slides of the same targets, or freeze-framed views from the filmed event. Slides of different facial views of targets among 12 foils, or dynamic 180 degrees mug shots of the same men, or multiple static views were administered 24 hr later in yes-no recognition tests. Recognition (d') was poorer for the same men seen in the event than in slides, but better for dynamic than for static mug shots. Nondynamic event characteristics were responsible for poor recognition of people seen in events, whereas dynamic aspects of facial transformations, not multiple views, seemed responsible for the superiority of dynamic mug shots. The implications of these results for issues of ecological validity of traditional face recognition methodology and for static feature models vs. dynamic transformation models of face recognition are discussed.  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