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   4739篇
  免费   401篇
  国内免费   341篇
  2024年   15篇
  2023年   235篇
  2022年   211篇
  2021年   401篇
  2020年   303篇
  2019年   251篇
  2018年   251篇
  2017年   158篇
  2016年   176篇
  2015年   200篇
  2014年   270篇
  2013年   243篇
  2012年   221篇
  2011年   239篇
  2010年   178篇
  2009年   255篇
  2008年   253篇
  2007年   186篇
  2006年   145篇
  2005年   125篇
  2004年   106篇
  2003年   129篇
  2002年   81篇
  2001年   73篇
  2000年   89篇
  1999年   67篇
  1998年   61篇
  1997年   51篇
  1996年   69篇
  1995年   35篇
  1994年   38篇
  1993年   44篇
  1992年   45篇
  1991年   39篇
  1990年   26篇
  1989年   26篇
  1988年   22篇
  1987年   18篇
  1986年   25篇
  1985年   34篇
  1984年   17篇
  1983年   17篇
  1982年   19篇
  1981年   9篇
  1980年   8篇
  1979年   5篇
  1978年   3篇
  1976年   3篇
  1975年   2篇
  1973年   2篇
排序方式: 共有5481条查询结果,搜索用时 0 毫秒
1.
2.
Patterns of conflict and cooperation both within and between societies may be related to the degree of cultural similarity within and between the same societies. A simple model of social learning is used to predict patterns of conflict and cooperation in hypothetical societies that differ in the roles of relatives and nonrelatives in the enculturation of children. The model is illustrated by comparing its predictions to known differences in the patterns of conflict between males inpatrilocal and matrilocal societies.  相似文献   
3.
Although the opportunity for errors in social learning is widely recognised, as yet little research has been directed towards understanding specific inaccuracies, biases and limitations in social learning and the mechanisms that give rise to them. In two experiments I ask how starlings, Sternus vulgaris, identify exemplars of novel feeders previously learned about socially. I find that starlings have a stronger response to feeders in the same context as that in which social learning took place, compared to identical and nonidentical feeders in a different context. Within a context that matches where social learning took place, starlings prefer feeders that show the same location and colour as the feeder demonstrated by the demonstrator starling, and show no preference when colour and location cues are dissociated. This suggests that starlings are relatively accurate social learners, since they show strong responses to novel foraging options only if they match the context, colour and location of options learned about socially, and they do so after very few trials. Furthermore, the responses of the subjects were compatible with conditioned learning-like mechanisms, which provide a useful basis for the further investigation of the origins and implications of errors in social learning.  相似文献   
4.
Since the first revelation of proteins functioning as macromolecular machines through their three dimensional structures, researchers have been intrigued by the marvelous ways the biochemical processes are carried out by proteins. The aspiration to understand protein structures has fueled extensive efforts across different scientific disciplines. In recent years, it has been demonstrated that proteins with new functionality or shapes can be designed via structure-based modeling methods, and the design strategies have combined all available information — but largely piece-by-piece — from sequence derived statistics to the detailed atomic-level modeling of chemical interactions. Despite the significant progress, incorporating data-derived approaches through the use of deep learning methods can be a game changer. In this review, we summarize current progress, compare the arc of developing the deep learning approaches with the conventional methods, and describe the motivation and concepts behind current strategies that may lead to potential future opportunities.  相似文献   
5.
6.
7.
8.
9.
Of two native Australian fishes naïve to the introduced toad Bufo marinus most barramundi Lates calcarifer rapidly learned to avoid B. marinus tadpoles, while sooty grunter Hephaestus fuliginosus exhibited considerable intraspecific variation in their learning ability. Some sooty grunter learned to avoid tadpoles after only a few attacks, while other individuals continued to attack and reject tadpoles throughout the entire laboratory trials. Individuals of both species recognized and avoided tadpoles 1 day after their previous encounter. None of the fishes died during the trials. The observed variation in behavioural responses of fishes to B. marinus may be due to differences in (1) learning ability, (2) fish hunger levels, and or (3) tadpole palatability and toxicity. The results demonstrate that most barramundi and sooty grunter learn to avoid B. marinus tadpoles with minimal trauma. Consequently, it is anticipated that the toads are unlikely to have a significant negative impact on wild populations of these fishes through direct toxic effects.  相似文献   
10.
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