全文获取类型
收费全文 | 71580篇 |
免费 | 2858篇 |
国内免费 | 20篇 |
专业分类
74458篇 |
出版年
2019年 | 900篇 |
2018年 | 1176篇 |
2017年 | 1194篇 |
2016年 | 1282篇 |
2015年 | 918篇 |
2014年 | 1136篇 |
2013年 | 5400篇 |
2012年 | 2072篇 |
2011年 | 2280篇 |
2010年 | 1400篇 |
2009年 | 1411篇 |
2008年 | 2006篇 |
2007年 | 2028篇 |
2006年 | 1891篇 |
2005年 | 1631篇 |
2004年 | 1553篇 |
2003年 | 1456篇 |
2002年 | 1547篇 |
2001年 | 2254篇 |
2000年 | 2280篇 |
1999年 | 1703篇 |
1998年 | 844篇 |
1997年 | 740篇 |
1996年 | 739篇 |
1995年 | 664篇 |
1993年 | 661篇 |
1992年 | 1432篇 |
1991年 | 1334篇 |
1990年 | 1319篇 |
1989年 | 1213篇 |
1988年 | 1198篇 |
1987年 | 1130篇 |
1986年 | 1217篇 |
1985年 | 1240篇 |
1984年 | 1029篇 |
1983年 | 957篇 |
1982年 | 693篇 |
1981年 | 685篇 |
1979年 | 1125篇 |
1978年 | 836篇 |
1975年 | 918篇 |
1974年 | 1001篇 |
1973年 | 1110篇 |
1972年 | 930篇 |
1971年 | 874篇 |
1970年 | 760篇 |
1969年 | 819篇 |
1968年 | 1038篇 |
1967年 | 956篇 |
1966年 | 801篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
201.
202.
Through school-sponsored health fairs, 398 adolescents (153 males and 245 females) between the ages of 14 and 18 completed a questionnaire on their compliance with six of the U.S. Dietary Guidelines. Results indicated that adolescents report highest compliance on "eat a variety of foods" and "eat foods with adequate starch and fiber." Conversely, they indicated low compliance on "reduce sugar intake" and "reduce fat, saturated fat and cholesterol intake." Sex differences were noted on two dietary guidelines. Females reported lower compliance with respect to "maintain desirable body weight." Males, on the other hand, reported lower compliance than females on "reduce salt intake." Given the fact that the dietary guidelines of "reduce fat, saturated fat and cholesterol," "maintain desirable body weight," and "reduce salt intake" are all aimed at reducing cardiovascular risk, the low compliance reported by adolescents may have long-range health implications. 相似文献
203.
204.
205.
206.
Context and structure in conceptual combination 总被引:8,自引:0,他引:8
207.
208.
Connectionism and cognitive architecture: a critical analysis 总被引:54,自引:0,他引:54
209.
A precursor of language acquisition in young infants 总被引:6,自引:0,他引:6
210.
H. O. F. Veiel G. Brill H. Hafner R. Welz 《American journal of community psychology》1988,16(6):839-861
The social support patterns of a sample of 101 suicide attempters were compared with the patterns of a control sample on the basis of structured interview data. Network characteristics and the extent of support in different functional categories were examined as to their absolute and relative power to discriminate between the suicide attempters and the controls. A clear separation of the functions of kin and of friends/acquaintances emerged. The crucial difference between the attempters and the controls lay in the number of friends with whom the subjects had agreeable everyday interactions and in the number of kin that provided crisis support, both psychological and instrumental. Other support differences between the two groups were of secondary importance. While there was no overall difference in the frequency of social interactions between the two groups, the size of the social network differed greatly. Consequences for the conceptualization and measurement of social support as well as for the prevention of suicidal behavior are discussed. 相似文献