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   39617篇
  免费   1628篇
  国内免费   14篇
  2020年   372篇
  2019年   428篇
  2018年   591篇
  2017年   602篇
  2016年   665篇
  2015年   505篇
  2014年   567篇
  2013年   2668篇
  2012年   1113篇
  2011年   1098篇
  2010年   685篇
  2009年   652篇
  2008年   985篇
  2007年   957篇
  2006年   844篇
  2005年   819篇
  2004年   761篇
  2003年   690篇
  2002年   719篇
  2001年   1277篇
  2000年   1242篇
  1999年   908篇
  1998年   406篇
  1997年   349篇
  1992年   873篇
  1991年   812篇
  1990年   828篇
  1989年   724篇
  1988年   726篇
  1987年   692篇
  1986年   728篇
  1985年   798篇
  1984年   599篇
  1983年   551篇
  1982年   375篇
  1981年   365篇
  1979年   697篇
  1978年   432篇
  1977年   423篇
  1976年   422篇
  1975年   592篇
  1974年   678篇
  1973年   725篇
  1972年   626篇
  1971年   587篇
  1970年   581篇
  1969年   572篇
  1968年   765篇
  1967年   673篇
  1966年   600篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
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   
35.
36.
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   
37.
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   
38.
39.
40.
Four experiments were conducted to determine whether echoic memory plays a role in differences between good and poor readers. The first two experiments used a suffix procedure in which the subject is read a list of digits with either a tone control or the word go appended to the list. For lists that exceeded the length of the subjects memory span by one digit (i.e., that avoided ceiling effects), the poor readers showed a larger decrement in the suffix condition than did the good readers. The third experiment was directed at the question of whether the duration of echoic memory is different for good and poor readers. Children shadowed words presented to one ear at a rate determined to give 75-85% shadowing accuracy. The items presented to the nonattended ear were words and an occasional digit. At various intervals after the presentation of the digit, a light signaled that the subject was to cease shadowing and attempt to recall any digit that had occurred in the nonattended ear recently. Whereas good and poor readers recalled the digit equally if tested immediately after presentation, the poor readers showed a faster decline in recall of the digit as retention interval increased. A fourth experiment was conducted to determine whether the differences in echoic memory were specific to speech stimuli or occurred at a more basic level of aural persistence. Bursts of white noise were separated by 9-400 ms of silence and the subject was to say whether there were one or two sounds presented. There were no differences in detectability functions for good and poor readers.  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