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   24194篇
  免费   1089篇
  国内免费   16篇
  2021年   197篇
  2020年   344篇
  2019年   406篇
  2018年   603篇
  2017年   575篇
  2016年   602篇
  2015年   432篇
  2014年   529篇
  2013年   2293篇
  2012年   928篇
  2011年   991篇
  2010年   607篇
  2009年   600篇
  2008年   841篇
  2007年   819篇
  2006年   815篇
  2005年   719篇
  2004年   671篇
  2003年   671篇
  2002年   665篇
  2001年   652篇
  2000年   603篇
  1999年   480篇
  1998年   302篇
  1997年   290篇
  1996年   282篇
  1995年   258篇
  1994年   232篇
  1993年   239篇
  1992年   344篇
  1991年   362篇
  1990年   332篇
  1989年   317篇
  1988年   284篇
  1987年   294篇
  1986年   289篇
  1985年   330篇
  1984年   310篇
  1983年   240篇
  1982年   234篇
  1981年   220篇
  1980年   194篇
  1979年   249篇
  1978年   207篇
  1977年   201篇
  1975年   227篇
  1974年   257篇
  1973年   263篇
  1972年   206篇
  1968年   201篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The present study tested gender as a moderator of the relationship between race-related stress and mental health symptoms among African American adults. Because African American women are exposed to stressors associated with race and gender, we hypothesized that African American women would have higher levels of race-related stress and more severe mental health outcomes related to experiences of race-related stress compared to African American men. Multivariate analyses revealed that African American men had higher stress appraisals for institutional racism than did women. No significant gender differences were found for cultural and individual racism. Moderated regression analyses revealed that increases in stress appraisals for individual racism were associated with increases in anxiety and obsessive-compulsive symptoms for African American women. Race-related stress had no significant effects on mental health symptoms for African American men. The findings suggest that gender is an important factor in determining the impact of race-related stress on mental health.  相似文献   
2.
Rats received Pavlovian conditioning in which food was signalled by a visual stimulus, A+, an auditory stimulus, B+, and a compound composed of different visual and auditory stimuli, CD+. Test trials were then given with the compound AB. Experiments 1 and 2A revealed stronger responding during AB than during CD. In Experiment 2B, there was no evidence of a summation of responding during AB when A+ B+ training was conducted in the absence of CD+ trials. A further failure to observe abnormally strong responding during ABwas found in Experiment 3 for which the training trials with A+ B+ CD+ were accompanied by trials in which C and D were separately paired with food. The results are explained in terms of a configural theory of conditioning, which assumes that responding during a compound is determined by generalization from its components, as well as from other compounds to which it is similar.  相似文献   
3.
Most arguments against active euthanasia, as do most arguments in applied ethics generally, take place within the framework of what can broadly be referred to as a modern, as opposed to an ancient, approach to moral theory. In this paper, I argue that this fact works to the disadvantage of opponents of active euthanasia, and that if there is a successful argument against active euthanasia, it will be of the latter sort. In Part I, I attempt to clarify thedistinction between modern and ancient approaches with which I am concerned. In Part II, I attempt to show that any argument against active euthanasia that is of the first sort is bound to fail. In Part III, I propose an argument against active euthanasia of the second sort that I believe has a better chance for success. In Part IV, I consider some objections that can be raised against this argument and attempt to show how they can be overcome.  相似文献   
4.
5.
6.
7.
8.
Several previous studies have shown that memory span is greater for short words than for long words. This effect is claimed to occur even when the short and long words are matched for the number of syllables and phonemes and so to provide evidence for subvocal articulation as being one mechanism that underlies memory span (Baddeley, Thomson, & Buchanan, 1975). The three experiments reported in this paper further investigate the articulatory determinants of word length effects on span tasks. Experiment 1 replicated Baddeley et al.'s finding of an effect of word length on auditory and visual span when the stimuli consist of words that differ in terms of the number of syllables. Experiments 2 and 3 showed that the effects of word length are eliminated when the words in the span task are matched for the number of syllables and phonemes but differ with respect to the duration and/or complexity of their articulatory gestures. These results indicate that it is the phonological structure of a word and not features of its actual articulation that determines the magnitude of the word length effect in span tasks.  相似文献   
9.
10.
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