全文获取类型
收费全文 | 20443篇 |
免费 | 247篇 |
国内免费 | 14篇 |
专业分类
教育 | 14952篇 |
科学研究 | 1599篇 |
各国文化 | 193篇 |
体育 | 1617篇 |
综合类 | 11篇 |
文化理论 | 199篇 |
信息传播 | 2133篇 |
出版年
2021年 | 177篇 |
2020年 | 324篇 |
2019年 | 455篇 |
2018年 | 581篇 |
2017年 | 620篇 |
2016年 | 586篇 |
2015年 | 363篇 |
2014年 | 477篇 |
2013年 | 3958篇 |
2012年 | 481篇 |
2011年 | 568篇 |
2010年 | 389篇 |
2009年 | 379篇 |
2008年 | 518篇 |
2007年 | 417篇 |
2006年 | 461篇 |
2005年 | 370篇 |
2004年 | 325篇 |
2003年 | 317篇 |
2002年 | 339篇 |
2001年 | 413篇 |
2000年 | 403篇 |
1999年 | 329篇 |
1998年 | 194篇 |
1997年 | 245篇 |
1996年 | 256篇 |
1995年 | 237篇 |
1994年 | 215篇 |
1993年 | 222篇 |
1992年 | 307篇 |
1991年 | 274篇 |
1990年 | 274篇 |
1989年 | 296篇 |
1988年 | 300篇 |
1987年 | 247篇 |
1986年 | 254篇 |
1985年 | 276篇 |
1984年 | 246篇 |
1983年 | 282篇 |
1982年 | 213篇 |
1981年 | 197篇 |
1980年 | 199篇 |
1979年 | 272篇 |
1978年 | 224篇 |
1977年 | 193篇 |
1976年 | 171篇 |
1975年 | 149篇 |
1974年 | 139篇 |
1973年 | 133篇 |
1971年 | 115篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
171.
172.
Tolar TD Lederberg AR Gokhale S Tomasello M 《Journal of deaf studies and deaf education》2008,13(2):225-240
Early developmental psychologists viewed iconic representation as cognitively less complex than other forms of symbolic thought. It is therefore surprising that iconic signs are not acquired more easily than arbitrary signs by young language learners. One explanation is that children younger than 3 years have difficulty interpreting iconicity. The current study assessed hearing children's ability to interpret the meaning of iconic signs. Sixty-six 2.5- to 5-year-olds who had no previous exposure to signs were required to match iconic signs to pictures of referents. Whereas few of the 2.5-year-olds recognized the meaning of the iconic signs consistently, more than half of the 3.0-year-olds and most of 3.5-year-olds performed above chance. Thus, the ability to recognize the meaning of iconic signs gradually develops during the preschool years. Implications of these findings for sign language development, receptive signed vocabulary tests, and the development of the ability to interpret iconic symbols are discussed. 相似文献
173.
Michael West 《European Journal of Psychology of Education - EJPE》1987,2(4):327-336
Student drug use has been investigated in many countries and a standard method of conducting such surveys is described here. Using an adapted World Health Organization questionnaire patterns of drug use were investigated among the population of secondary school students in Bermuda (N=3,930). The prevalence of use of alcohol and eight illicit drugs is described and related to students’ attitudes, life-styles and demographic characteristics. Factors such as age, sex, race, parental use of alcohol, leisure time activities, allowances and beliefs about drugs all emerge (as they have in other studies) as strongly related to drug use. It is concluded that though these cross cultural similarities exist, there are important sub-cultural differences in drug use patterns which reflect social dynamics and characteristics within communities. It is suggested that a focus on sub-cultural differences may be particularly valuable in future research. 相似文献
174.
175.
176.
177.
1 Introduction Duringthe past several decades ,considerable atten-tion has been given to devising methods for solvingconstrained opti mization problemsviaunconstrainedmini mization techniques and a number of researchwork in the area of nonlinear programmi… 相似文献
178.
179.
180.