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   9272篇
  免费   354篇
  国内免费   7篇
  2021年   89篇
  2020年   136篇
  2019年   149篇
  2018年   195篇
  2017年   215篇
  2016年   232篇
  2015年   163篇
  2014年   181篇
  2013年   975篇
  2012年   337篇
  2011年   351篇
  2010年   239篇
  2009年   257篇
  2008年   349篇
  2007年   375篇
  2006年   343篇
  2005年   309篇
  2004年   278篇
  2003年   336篇
  2002年   307篇
  2001年   130篇
  2000年   132篇
  1999年   150篇
  1998年   125篇
  1997年   126篇
  1996年   127篇
  1995年   139篇
  1994年   107篇
  1993年   126篇
  1992年   117篇
  1991年   105篇
  1990年   81篇
  1989年   90篇
  1988年   91篇
  1987年   99篇
  1986年   87篇
  1985年   96篇
  1984年   122篇
  1983年   124篇
  1982年   118篇
  1981年   115篇
  1980年   114篇
  1979年   114篇
  1978年   124篇
  1977年   114篇
  1976年   131篇
  1975年   96篇
  1974年   102篇
  1973年   93篇
  1972年   63篇
排序方式: 共有9633条查询结果,搜索用时 0 毫秒
121.
People generally intend to act more on beliefs and attitudes about which they have greater certainty. However, we introduce a boundary condition to the positive association between certainty and behavioral intentions—behavioral extremity. Uncertainty about a threatening issue like COVID-19 can be disconcerting, and we propose that uncertain people cope in part through increased openness to extreme actions like accepting risky medical treatments and aggression toward those defying mitigation policies. Testing this, we compiled and analyzed all the data on certainty about COVID-19 mitigation policies and willingness to engage in mitigation-related behaviors that our lab collected during the pandemic (6 samples, 20 behaviors, Ns up to 1496). External ratings of the behaviors' extremity moderated certainty-willingness associations: whereas greater certainty was associated with increased willingness to engage in moderate behaviors (the typical result), lower certainty was associated with increased willingness to engage in extreme behaviors, especially among those worried about becoming ill.  相似文献   
122.
123.
124.
125.
Recall of complex sentences at two retention intervals was examined, using sentences which varied simultaneously in three ways, being either active or passive, of low or high Yngve depth, and predictable or unpredictable. Recall of any particular sentence was cued with either the logical subject, logical object, verb or adverbial phrase noun. In general, unpredictable sentences were recollected better than predictable ones, low Yngve depth sentences were recalled better than high Yngve depth ones, and passive sentences were retained better than active ones. The most effective cue was the object, followed in turn by the subject and the adverbial phrase noun, with the verb being least effective. Implications of these findings are discussed.  相似文献   
126.
127.
Two experiments were run to investigate the locus of selectivity in a visual memory task involving differential payoff for letters correctly recalled: Major variables consisted of value instructions given before or after the exposure of a display, the ratio of high to low value, and exposure duration. The results showed that Ss make more correct reports of higher value than of lesser value, whether value instructions are given before or after the display. Furthermore, overall performance and extent of selectivity increase with increasing exposure time, but more for the before than the after conditions of instruction. These results suggest that selectivity occurs both during perception and retention and during recall.  相似文献   
128.
Tables of sequences of two-class events are presented for use in programming psychological experiments in which behavior on trial n may be a function of the events of trials n ? 1, n ? 2, and/or n ? 3. Various factors related to schedule generation are discussed, i.e., restrictions on trial-block length which accompany sequential balance, interrelationships of trial blocks in the multiblock experiment, relationships between run length and r-tuple occurrences, and alternation behavior. Following a consideration of various methods of schedule generation for the two-class experiment, it was concluded that no method can result in schedules that possess all properties considered desirable in psychological experiments. However, the present sequences allow for sequential balance and analysis, and thus should prove useful in producing schedules in some contexts that are standard with regard to sequential influences.  相似文献   
129.
130.
The statistical aspects of quantum explanation are intrinsic to quantum physics; individual quantum events are created in the interactions associated with observation and are not describable by predictive theory. The superposition principle shows the essential difference between quantum and non-quantum physics, and the principle is exemplified in the classic single-photon two-slit interference experiment. Recently Mandel and Pfleegor have done an experiment somewhat similar to the optical single-photon experiment but with two independently operated lasers; interference is obtained even with beam intensity so small that only one photon is in the apparatus at a time. The result can be understood in terms of the superposition of states; or, in terms of the Uncertainty Principle, which is found to forbid the determination of which of the two lasers is the source of a given photon (if conditions for interference are to obtain). The Mandel-Pfleegor experiment gives a physical argument against the continuous localization of a photon that is assumed in the hidden variable theories and therefore gives further support for the generally accepted view that an observed entity (observed state) is created in the observation event. This aspect of quantum physics implies a subjectivism on the level of individual quantum-level occurrences, since there is in quantum theory no basis for asserting the existence of the event independently of observation of it. Extension of this subjectivism to large scale, non-quantum phenomena falls within the principles of quantum theory; counter considerations that argue against such an extension are noted.  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