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   75852篇
  免费   3047篇
  国内免费   30篇
  78929篇
  2020年   824篇
  2019年   962篇
  2018年   1398篇
  2017年   1407篇
  2016年   1485篇
  2015年   1059篇
  2014年   1312篇
  2013年   6259篇
  2012年   2393篇
  2011年   2438篇
  2010年   1501篇
  2009年   1511篇
  2008年   2170篇
  2007年   2083篇
  2006年   1935篇
  2005年   1626篇
  2004年   1657篇
  2003年   1597篇
  2002年   1570篇
  2001年   2385篇
  2000年   2243篇
  1999年   1715篇
  1998年   837篇
  1997年   761篇
  1996年   808篇
  1995年   743篇
  1992年   1466篇
  1991年   1360篇
  1990年   1331篇
  1989年   1273篇
  1988年   1257篇
  1987年   1181篇
  1986年   1209篇
  1985年   1238篇
  1984年   1034篇
  1983年   897篇
  1979年   1092篇
  1978年   843篇
  1977年   701篇
  1976年   709篇
  1975年   878篇
  1974年   1036篇
  1973年   1091篇
  1972年   898篇
  1971年   857篇
  1970年   777篇
  1969年   790篇
  1968年   975篇
  1967年   880篇
  1966年   867篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
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   
43.
44.
45.
46.
47.
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   
48.
49.
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   
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