全文获取类型
收费全文 | 35311篇 |
免费 | 677篇 |
国内免费 | 3篇 |
专业分类
35991篇 |
出版年
2023年 | 81篇 |
2021年 | 124篇 |
2020年 | 198篇 |
2019年 | 275篇 |
2018年 | 3730篇 |
2017年 | 3112篇 |
2016年 | 2560篇 |
2015年 | 484篇 |
2014年 | 428篇 |
2013年 | 1837篇 |
2012年 | 1170篇 |
2011年 | 2950篇 |
2010年 | 2834篇 |
2009年 | 1803篇 |
2008年 | 2234篇 |
2007年 | 2668篇 |
2006年 | 543篇 |
2005年 | 749篇 |
2004年 | 704篇 |
2003年 | 633篇 |
2002年 | 581篇 |
2001年 | 300篇 |
2000年 | 284篇 |
1999年 | 250篇 |
1998年 | 259篇 |
1997年 | 238篇 |
1996年 | 195篇 |
1995年 | 191篇 |
1994年 | 169篇 |
1993年 | 201篇 |
1992年 | 189篇 |
1991年 | 167篇 |
1990年 | 183篇 |
1989年 | 144篇 |
1988年 | 145篇 |
1987年 | 151篇 |
1986年 | 141篇 |
1985年 | 167篇 |
1984年 | 208篇 |
1983年 | 209篇 |
1982年 | 201篇 |
1981年 | 176篇 |
1980年 | 146篇 |
1979年 | 144篇 |
1978年 | 188篇 |
1977年 | 168篇 |
1976年 | 168篇 |
1975年 | 145篇 |
1974年 | 164篇 |
1973年 | 112篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
Noelle Yuen Naleen Andrade Linda Nahulu George Makini John F. McDermott George Danko Ronald Johnson Jane Waldron 《Suicide & life-threatening behavior》1996,26(1):27-36
Native Hawaiian high school students, N = 1779, were surveyed for symptoms of psycho-pathology and suicide attempts in the previous 6 months. Seventy-seven (4.3%) of the students reported making a suicide attempt. There were no significant differences in prevalence rates for males and females. Depression, anxiety, aggression, substance abuse symptoms, and low family support, but not peer support, were significantly correlated with suicide attempts. On logistic regression, depression, substance abuse, and family support independently predicted attempts. The lack of gender difference may indicate a cultural characteristic of the Hawaiian population that differentiates it from mainstream American populations but likens it to the Native American population. 相似文献
35.
36.
37.
38.
39.
Subjects (N= 28) performing a complex disjunctive concept-formation task on a microcomputer were given the opportunity to seek help following failure to correctly identify concepts. The proportion of those seeking help was significantly greater when the source of help was the computer itself (86%) rather than another person (36%). Consistent with past research, those who did not ask for help gave reasons other than the potential negative social consequences of doing so. Self-report data and a systematic test for the presence of experimenter-induced demand ruled out several possible sources of confounding. The results have implications for designers of time-sharing and networked computer systems. 相似文献
40.
The individual deciding on a nuclear weapons production policy is faced with a dilemma in which a choice must be made to support one of several conflicting defense policies. In order to investigate the social-psychological variables that are related to armament policy decision making, a telephone survey was conducted in the City of St. Louis, Missouri. Adult subjects (N= 110) responded to questions concerned with cognitive, attitudinal, and emotional responses to nuclear arms. Participants were also asked to choose a weapons production policy for the United States under conditions of continued and decreased Soviet nuclear arms production. Results indicated that respondents decisions about nuclear weapons production were related to their support for deterrence, the availability of their nuclear-related images, their emotional response to nuclear war, their attributions of responsibility for the prevention of nuclear war, and their political party affiliation. Distinctions between antinuclear decision-makers and pronuclear decision-makers are discussed. 相似文献