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   6750篇
  免费   164篇
  国内免费   3篇
  2023年   39篇
  2022年   38篇
  2021年   50篇
  2020年   84篇
  2019年   106篇
  2018年   222篇
  2017年   237篇
  2016年   322篇
  2015年   182篇
  2014年   127篇
  2013年   324篇
  2012年   383篇
  2011年   372篇
  2010年   98篇
  2009年   87篇
  2008年   141篇
  2007年   139篇
  2006年   152篇
  2005年   1387篇
  2004年   729篇
  2003年   505篇
  2002年   178篇
  2001年   57篇
  2000年   27篇
  1999年   45篇
  1997年   16篇
  1996年   17篇
  1995年   18篇
  1994年   24篇
  1992年   38篇
  1991年   48篇
  1990年   70篇
  1989年   51篇
  1988年   32篇
  1987年   47篇
  1986年   48篇
  1985年   36篇
  1984年   30篇
  1983年   24篇
  1979年   36篇
  1975年   32篇
  1974年   33篇
  1973年   30篇
  1972年   26篇
  1971年   26篇
  1970年   20篇
  1969年   19篇
  1968年   17篇
  1967年   19篇
  1966年   16篇
排序方式: 共有6917条查询结果,搜索用时 31 毫秒
51.
Twenty six clinically healthy smokers were studied with transient pattern visual-evoked potentials. In comparison with a sample of "normal" subjects we found a difference of some parameters (P less than 0.05): the P2-latency and the interocular difference of latency on average were 6-7 ms respectively 2 ms larger. Thirteen subjects have had a prolonged P2-latency (P less than 0.05) and/or a difference in interocular latencies larger than 5 ms. These findings may suggest on subclinical disturbances of visual system and indicators of an special sensitivity of that person. The findings are possibly related to tobacco-alcohol amblyopia.  相似文献   
52.
Aged rats with extensive prior training on the radial maze retain the capacity for accurate spatial working memory (WM) for at least 3 months without practice. To investigate the temporal limits of this influence of prior experience we compared the reacquisition of spatial WM by a group of experienced 21.5-month-old rats to the original acquisition by naive 3-month-old rats. The aged rats had received 225 radial maze tests between 3 and 11 months of age. Despite 10 months without practice the old rats rapidly reacquired critical performance. Their reacquisition was markedly superior to original learning by the young rats, even when delays as long as 5 h were imposed between the rats' fourth and fifth choices during the daily tests in the eight-arm maze. Additional tests showed that neither young nor old rats employed a response strategy to maintain accurate spatial WM performance. Experience clearly confers long-lived protection against the otherwise deleterious effects of aging on spatial WM, but the mechanism by which this influence arises is unknown.  相似文献   
53.
The ability to think of a previously studied item has often been shown to be impaired when, in one way or another, the extraitem context is changed from study to test. In a series of five experiments, such impairment is induced in a somewhat different way. A fragment (e.g. r-i--rop) of a just-studied word (raindrop) is shown to be less readily completed if it is presented bit by bit (r------p, r----r-p, r-i--r-p, r-i--rop) rather than all at once (Experiments 1, 3, 4, and 5). No such effect is found if the word has not been studied beforehand (Experiments 2, 3, 4, and 5). This pattern of results occurs even when fragments of studied and nonstudied words occur in the same test and under conditions in which subjects cannot tell whether a given fragment is of a studied or nonstudied word (Experiments 4 and 5). In addition, for words that have been studied beforehand, the impairment is shown to increase systematically with the number of steps involved in the presentation of the word fragment (Experiment 3) and also to persist when the time allowed for completion of the final version of the fragment is increased from 4 s to a full minute (Experiment 5).  相似文献   
54.
Twenty of 150 boys living in a residential setting who were emitting high levels of impulsive/aggressive behavior participated in a study of the effectiveness of a cognitive-behavioral group treatment procedure designed to equip them with skills conducive to alternate and more socially appropriate behavior. Treatment involved 13 meetings of 55 minutes duration over a six-week period. The results indicated significant behavioral changes in school regarding: (1) the intensity of physical fighting, (2) the frequency and intensity of verbal fighting, (3) noncompliance, and (4) being in an inappropriate location. These behavioral changes did not generalize beyond the school setting. Significant increases in the number of identified logical consequences of aggressive behavior and in the number of alternative responses to aggressive behavior were observed compared to control boys. The behavioral changes observed in school largely extinguished during the five weeks between the last treatment session and the follow-up observations.  相似文献   
55.
56.
57.
The somatic and psychosocial development of 80 subjects with manifest affective-phasic psychoses is studied retrospectively and compared with that of an identically sized control group consisting of neuropsychiatrically healthy subjects. Statistically significant differences were found particularly in the answers to questions dealing with social situation and social adaptability. Achievement at school and vocational qualifications were lower among the parents of the patients than among those of the healthy subjects. Characteristic features of the patients' childhood and adolescence were transient depression, often for no apparent cause, and maladaption, and vocational wishes were fulfilled less often than among the controls. The patients experienced greater difficulty in settling in to a new group due to their contact difficulties.  相似文献   
58.
By 48 patients with Wilson's disease the brainstem acoustic evoked potentials were stated. There were 35 pathological findings (73%), 13 were normal (27%). The waves, determined by the middle and upper brainstem (Pons and Mesencephalon) showed most of all pathological changes. Those patients with forms of Wilson's disease called Pseudoskelerose and Pseudoparkinson showed the most pathological findings. But one could watch these findings by about 30% of patients in preclinical stage. This method can possibly be used for early detection of disorders of brainstem functions and in the same way it can be used for control of treatment by patients in preclinical stage.  相似文献   
59.
We test the hypothesis that COVID-19 vaccine hesitancy is attributable to distrustful complacency—an interactive combination of low concern and low trust. Across two studies, 9,695 respondents from different parts of Britain reported their level of concern about COVID-19, trust in the UK government, and intention to accept or refuse the vaccine. Multilevel regression analysis, controlling for geographic area and relevant demographics, confirmed the predicted interactive effect of concern and trust. Across studies, respondents with both low trust and low concern were 10%–22% more vaccine hesitant than respondents with either high trust or high concern, and 26%–29% more hesitant than respondents with both high trust and high concern. Results hold equally among White, Black, and Muslim respondents, consistent with the view that regardless of mean-level differences, a common process underlies vaccine hesitancy, underlining the importance of tackling distrustful complacency both generally and specifically among unvaccinated individuals and populations.  相似文献   
60.
Although abortion in China has been legalized for several decades, it is still controversial and the woman and man involved are at risk of being stigmatized. The current research replicated two studies conducted in Italy by investigating how the abortion decision of the woman and man influence received moral outrage, dehumanization, and perceptions of female professional competence. Study 1, which only included female participants, found higher moral outrage toward a woman having an abortion when the pregnancy was depicted as referring to a “child” (vs. “foetus”), and higher dehumanization of the woman in terms of human nature. Study 2, which included both male and female participants, and clarified responsibility for the abortion decision with respect to the woman and the man, revealed higher moral outrage and a reduction in the attribution of human uniqueness to the man, and of human nature to both the woman and the man. Moral outrage mediated dehumanization when participants had low positive attitudes toward abortion in Study 1 and high positive attitudes in Study 2. Both studies showed a negative impact of the decision to have an abortion on the woman's perceived traditional professional competence. The results generally align with the findings from Italy and yield some practical implications on reducing abortion stigma. Future abortion stigma research should consider more gender-related factors.  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