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   74981篇
  免费   2361篇
  国内免费   21篇
  77363篇
  2020年   686篇
  2019年   815篇
  2018年   4263篇
  2017年   3680篇
  2016年   3223篇
  2015年   1051篇
  2014年   1116篇
  2013年   5001篇
  2012年   2476篇
  2011年   4105篇
  2010年   3464篇
  2009年   2557篇
  2008年   3237篇
  2007年   3656篇
  2006年   1539篇
  2005年   1467篇
  2004年   1453篇
  2003年   1346篇
  2002年   1242篇
  2001年   1954篇
  2000年   1859篇
  1999年   1365篇
  1998年   643篇
  1997年   559篇
  1996年   620篇
  1995年   552篇
  1994年   551篇
  1993年   535篇
  1992年   1111篇
  1991年   1018篇
  1990年   1007篇
  1989年   964篇
  1988年   941篇
  1987年   874篇
  1986年   865篇
  1985年   915篇
  1984年   736篇
  1983年   634篇
  1982年   482篇
  1979年   764篇
  1978年   567篇
  1975年   602篇
  1974年   684篇
  1973年   704篇
  1972年   606篇
  1971年   563篇
  1970年   486篇
  1968年   613篇
  1967年   533篇
  1966年   506篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
Do the conditions under which promises are made determine whether they ought to be kept? Philosophers have placed a number of conditions on promising which, they hold, must be met in order to make promise-keeping obligatory. In so doing, they have distinguished valid promises from invalid promises and justified promises from promises that are not justified. Considering such conditions, one by one, we argue that they are mistaken. In the first place, the conditions they lay down are not necessary for either valid or justified promise-making. In the second place, promises need not meet such conditions in order to create moral obligations. In general, such analyses of promising fail because they suffer from a confusion between promise-making and promise-keeping. Philosophers have wrongly supposed that obligations to keep promises are dependent upon, or derivable from, the quality of the promises themselves, at the time they are made, instead of focusing on conditions that must be satisfied at the time when promises are supposed to be kept. It is not the quality of a promise that determines an obligation to keep it but the rightness or wrongness of performing the promised act.  相似文献   
32.
33.
34.
35.
Previous work on children's intuitive knowledge about the natural world has documented their difficulty in acquiring an overarching concept of biological life that includes plants as well as humans and non‐human animals. It has also suggested that the acquisition of fundamental biological concepts like alive and die may be influenced by the language used to describe them, as evidenced by differences between English‐ and Indonesian‐speaking children's performance in tasks involving these concepts. Here, we examine one particularly important source of linguistic information available to children during this acquisition process: everyday conversations with their parents. We take a cross‐linguistic approach in analysing the evidence available to English‐ and Indonesian‐speaking children as they acquire meanings for words corresponding to the concepts alive and die . Our analysis illustrates that young children acquiring English and Indonesian are faced with distinct problems, but that parental input in both languages does little to support the acquisition of broad, inclusive biological concepts.  相似文献   
36.
37.
Logical connectives, such as “AND”, “OR”, “IF . . . THEN”, and “IF AND ONLY IF” are ubiquitous in both language and cognition; however, reasoning with logical connectives is error-prone. We argue that some of these errors may stem from people's tendency to minimize the number of possibilities compatible with logical connectives and to construct a “minimalist” one-possibility representation. As a result, connectives denoting a single possibility (e.g., conjunctions) are likely to be represented correctly, whereas connectives denoting multiple possibilities (e.g., disjunctions or conditionals) are likely to be erroneously represented as conjunctions. These predictions were tested and confirmed in three experiments using different paradigms. In Experiment 1, participants were presented with a multiple-choice task and asked to select all and only those possibilities that would indicate that compound verbal propositions were true versus false. In Experiment 2, a somewhat similar task was used, except that participants were asked later to perform a cued recall of verbal propositions. Finally, Experiment 3 used an old/new recognition paradigm to examine participants' ability to accurately recognize different logical connectives. The results of the three experiments are discussed in relation to theories of representation of possibilities and theories of reasoning.  相似文献   
38.
39.
40.
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