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   93840篇
  免费   3860篇
  国内免费   31篇
  2020年   968篇
  2019年   1237篇
  2018年   1647篇
  2017年   1695篇
  2016年   1849篇
  2015年   1331篇
  2014年   1545篇
  2013年   7035篇
  2012年   2876篇
  2011年   3033篇
  2010年   1886篇
  2009年   1829篇
  2008年   2660篇
  2007年   2610篇
  2006年   2368篇
  2005年   2156篇
  2004年   2023篇
  2003年   1915篇
  2002年   1972篇
  2001年   2857篇
  2000年   2816篇
  1999年   2122篇
  1998年   1061篇
  1997年   923篇
  1996年   913篇
  1992年   1857篇
  1991年   1740篇
  1990年   1761篇
  1989年   1585篇
  1988年   1571篇
  1987年   1482篇
  1986年   1581篇
  1985年   1651篇
  1984年   1361篇
  1983年   1244篇
  1982年   874篇
  1981年   845篇
  1979年   1443篇
  1978年   1016篇
  1977年   873篇
  1975年   1211篇
  1974年   1351篇
  1973年   1435篇
  1972年   1238篇
  1971年   1154篇
  1970年   1072篇
  1969年   1090篇
  1968年   1434篇
  1967年   1281篇
  1966年   1122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Evaluated the effect of varied physician affect on subject recall, anxiety, and perceptions in a simulated tense and ambiguous medical situation. Forty women at risk for breast cancer viewed videotapes of an oncologist presenting--with either worried or nonworried affect--mammogram results. Although the mammogram results and the oncologist were the same in both presentation, analyses indicated that, compared to the women receiving the results from a nonworried physician, the women receiving the results from a worried physician recalled significantly less information, perceived the clinical situation as significantly more severe, reported significantly higher levels of state anxiety, and had significantly higher pulse rates. These results suggest that physician affect plays a critical role in patient reaction to medical information. Implications for compliance research, patient satisfaction, and physician training are discussed.  相似文献   
42.
The ability of two species of tits to remember the location and/or features of an object was tested in a delayed-matching-to-sample procedure. Three values of retention interval between presentation of the sample stimulus and the choice--30 sec, 5 min, and 15 min--were used. Both species performed at above-chance level at all retention intervals, and there was no significant decline in accuracy with increasing interval. A pool of 100 stimulus objects was used, but the results of control trials indicated that the birds responded primarily to location rather than stimulus features of the object itseif. Although the food-storing marsh tit tended to perform at a higher level than the non-storing great tit, the only significant difference between the species was in the first 50 trials of the first treatment, when the birds were acquiring the task. The results are discussed in relation to the hypothesized special memory capacity of food-storing birds.  相似文献   
43.
Experiment 1 replicated Yaniv and Meyer's (1987) finding that lexical decision and episodic recognition performance was better for words previously yielding high-accessibility levels (a combination of feeling-of-knowing and tip-of-the-tongue ratings) in comparison with those yielding low-accessibility levels in a rare word definition task. Experiment 2 yielded the same pattern even though lexical decisions preceded accessibility estimates by a full week. Experiment 3 dismissed the possibility that the Experiment 2 results may have been due to a long-term influence from the lexical decision task to the rare word judgment task. These results support a model in which Ss (a) retrieve topic familiarity information in making accessibility estimates in the rare word definition task and (b) use this information to modulate lexical decision performance.  相似文献   
44.
45.
Most studies of suicide in younger patients have demonstrated significant alterations in the serotonin system. Although a high percentage of completed suicides occur in late-life, to date very few studies of the biology of suicide have focused on this age group. This chapter describes age-related changes in the central nervous system pertinent to the biology of suicide, then reviews post-mortem biological studies of the brains of suicides and suicide attempters. As suicide attempts in the elderly are characterized by the use of violent means, biologic studies of impulsive violence are discussed. Finally we describe data on the effect of degenerative diseases on the serotonin system and the possible link to increased suicidal behavior in affected patients. This review underscores the need for further study of the biology of suicide in the geriatric age group.  相似文献   
46.
47.
48.
Convergent and divergent stereo mechanisms were compared in their ability to recover structure from motion. Contrary to a recent result reported by Richards and Lieberman, no difference in their performance was found; both mechanisms appeared equally capable of supporting the perception of good structure from motion. Possible reasons for the disparate results are discussed.  相似文献   
49.
50.
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