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   38977篇
  免费   1579篇
  国内免费   14篇
  2020年   358篇
  2019年   414篇
  2018年   570篇
  2017年   581篇
  2016年   645篇
  2015年   485篇
  2014年   553篇
  2013年   2598篇
  2012年   1100篇
  2011年   1061篇
  2010年   683篇
  2009年   645篇
  2008年   955篇
  2007年   943篇
  2006年   817篇
  2005年   790篇
  2004年   738篇
  2003年   670篇
  2002年   689篇
  2001年   1265篇
  2000年   1221篇
  1999年   891篇
  1998年   399篇
  1997年   348篇
  1992年   866篇
  1991年   808篇
  1990年   824篇
  1989年   714篇
  1988年   718篇
  1987年   689篇
  1986年   721篇
  1985年   794篇
  1984年   598篇
  1983年   548篇
  1982年   369篇
  1981年   360篇
  1979年   693篇
  1978年   428篇
  1977年   420篇
  1976年   416篇
  1975年   583篇
  1974年   673篇
  1973年   715篇
  1972年   619篇
  1971年   579篇
  1970年   574篇
  1969年   564篇
  1968年   756篇
  1967年   669篇
  1966年   600篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
33.
An electronic apparatus using infrared beams for monitoring the movements of individual bees under dark conditions is described. The searching behavior of workers in an arena was monitored over 2-h periods. Mean ambulatory velocity for one bee over a distance of 100 mm was 45.6±1.51 mm/sec (n=45). Thigmokinesis and temporal activity patterns are illustrated.  相似文献   
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.
This paper examines college students' attributions about suicide as a function of gender and context (athletic vs. relationship failure). Results indicated that male athletes who suicided were considered more emotionally well-adjusted compared to males who suicided because of a relationship failure and all females. Male and female athletes who suicided were seen as more competent and less distressed compared to those who suffered a failed relationship. Females were also seen as more distressed compared to males. These results are discussed in terms of a positive bias toward athletes in our society as well as gender stereotypes. Implications of these findings as well as methodological limitations are discussed.  相似文献   
37.
38.
39.
There is a type of explanation frequently employed in the sciences, particularly the quantitative ones, that I intend to focus on. It seeks to understand some phenomenon or regularity that occurs in a type of system S by deriving an equation describing that phenomenon or regularity from a set of equations that govern S. I want to propose a way of understanding such explanations.  相似文献   
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