全文获取类型
收费全文 | 68433篇 |
免费 | 2573篇 |
国内免费 | 26篇 |
专业分类
71032篇 |
出版年
2020年 | 703篇 |
2019年 | 847篇 |
2018年 | 1201篇 |
2017年 | 1217篇 |
2016年 | 1296篇 |
2015年 | 923篇 |
2014年 | 1126篇 |
2013年 | 6011篇 |
2012年 | 1965篇 |
2011年 | 2001篇 |
2010年 | 1302篇 |
2009年 | 1237篇 |
2008年 | 1840篇 |
2007年 | 1771篇 |
2006年 | 1640篇 |
2005年 | 1417篇 |
2004年 | 1339篇 |
2003年 | 1314篇 |
2002年 | 1305篇 |
2001年 | 2093篇 |
2000年 | 2004篇 |
1999年 | 1541篇 |
1998年 | 712篇 |
1996年 | 777篇 |
1995年 | 761篇 |
1994年 | 752篇 |
1993年 | 716篇 |
1992年 | 1459篇 |
1991年 | 1308篇 |
1990年 | 1335篇 |
1989年 | 1186篇 |
1988年 | 1216篇 |
1987年 | 1178篇 |
1986年 | 1189篇 |
1985年 | 1124篇 |
1984年 | 1022篇 |
1983年 | 895篇 |
1982年 | 689篇 |
1979年 | 1059篇 |
1978年 | 766篇 |
1975年 | 906篇 |
1974年 | 930篇 |
1973年 | 1031篇 |
1972年 | 879篇 |
1971年 | 821篇 |
1970年 | 728篇 |
1969年 | 764篇 |
1968年 | 924篇 |
1967年 | 822篇 |
1966年 | 745篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
31.
32.
33.
34.
35.
36.
Kristine L S P McVea 《Health psychology》2006,25(5):558-562
OBJECTIVE: This report reviews the evidence that informs the role of health and mental health care providers in addressing youth smoking cessation. DESIGN: Qualitative literature review. RESULTS: Physicians do not consistently screen adolescents for tobacco use and fail to provide recommended cessation advice. Challenges to addressing smoking cessation include the need for procedures to ensure confidentiality and the existence of competing demands to provide other services. Few published studies have specifically addressed the effectiveness of clinical interventions. Interventions that require return visits or follow-up phone contacts are technically difficult to implement in this population. Successful interventions may require resources not available in nonresearch settings. Most studies have used brief clinical intervention as a control condition, making it impossible to evaluate its effectiveness. CONCLUSION: There is little evidence that supports current clinical smoking cessation guidelines for adolescents. More research is needed to develop inexpensive, efficient clinical interventions that can provide youths access to smoking cessation help. Future challenges include reorganizing clinical systems to offer greater counseling by support staff or in electronic formats and to provide effective booster messages and follow-up care in a population that is difficult to track. 相似文献
37.
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
38.
Erin M. Leddon Sandra R. Waxman Douglas L. Medin 《The British journal of developmental psychology》2011,29(3):375-395
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
39.
Carol VanZile-Tamsen Maria Testa Lisa L Harlow Jennifer A Livingston 《Health psychology》2006,25(2):249-254
The current study was designed to gain a better understanding of the nature of the relationship between substance use and sexual risk taking within a community sample of women (N = 1,004). Using confirmatory factor analysis, the authors examined the factor structure of sexual risk behaviors and substance use to determine whether they are best conceptualized as domains underlying a single, higher order, risk-taking propensity. A 2 higher order factor model (sexual risk behavior and substance use) provided the best fit to the data, suggesting that these 2 general risk domains are correlated but independent factors. Sensation seeking had large general direct effects on the 2 risk domains and large indirect effects on the 4 first-order factors and the individual indicators. Negative affect had smaller, yet still significant, effects. Impulsivity and anxiety were unrelated to sexual health risk domains. 相似文献
40.
Extensive empirical evidence confirms a depressed entitlement effect wherein women pay themselves less than men for comparable work and believe the allocation fair. The present study tests the hypothesis that status subordination linked to being female underlies at least some of this effect. A 2 × 3 design crossed 180 undergraduates' gender with a control condition, which successfully established the depressed entitlement effect, and two experimental conditions. In one, women's status was enhanced through legitimation of women's task abilities; in the other, both women's and men's status was enhanced by adding educational credentials relevant to task ability. Follow-up analyses of the significant interaction revealed that the gap in self-pay demonstrated in the control condition disappeared when women's status was enhanced such that higher-status women's self-pay equaled that of men and exceeded that of control women. Although these findings confirm that status plays a role in producing depressed entitlement in self-pay, ancillary analyses of participants' perceptions point to the persistence of shifting standards and men's resistance to status threats. 相似文献