全文获取类型
收费全文 | 74322篇 |
免费 | 3048篇 |
国内免费 | 46篇 |
出版年
2020年 | 892篇 |
2019年 | 1090篇 |
2018年 | 1507篇 |
2017年 | 1484篇 |
2016年 | 1631篇 |
2015年 | 1143篇 |
2014年 | 1377篇 |
2013年 | 6225篇 |
2012年 | 2456篇 |
2011年 | 2549篇 |
2010年 | 1673篇 |
2009年 | 1718篇 |
2008年 | 2314篇 |
2007年 | 2263篇 |
2006年 | 2033篇 |
2005年 | 1798篇 |
2004年 | 1763篇 |
2003年 | 1698篇 |
2002年 | 1674篇 |
2001年 | 2305篇 |
2000年 | 2245篇 |
1999年 | 1708篇 |
1998年 | 894篇 |
1997年 | 790篇 |
1996年 | 697篇 |
1995年 | 744篇 |
1994年 | 714篇 |
1993年 | 716篇 |
1992年 | 1401篇 |
1991年 | 1329篇 |
1990年 | 1288篇 |
1989年 | 1184篇 |
1988年 | 1161篇 |
1987年 | 1112篇 |
1986年 | 1062篇 |
1985年 | 1174篇 |
1984年 | 987篇 |
1983年 | 835篇 |
1982年 | 705篇 |
1979年 | 1020篇 |
1978年 | 782篇 |
1977年 | 737篇 |
1976年 | 705篇 |
1975年 | 838篇 |
1974年 | 920篇 |
1973年 | 967篇 |
1972年 | 789篇 |
1968年 | 790篇 |
1967年 | 701篇 |
1966年 | 728篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
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
64.
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
65.
66.
67.
68.
In this paper, we organize past and present theories and models of creativity by using a new conceptual framework—the creativity matrix—with the aim of highlighting the dimensions of creativity we know a lot about and those we tend to either ignore or find difficult to study. This matrix is formed by bringing together a developmental model of creativity (the 4 C's) and a structural one (the 5 A's). We start by briefly describing these two conceptual frameworks, and then, we proceed to exploring the matrix itself by describing how the 5 A's are dynamically organized at each “level” of the 4 C's. Importantly, our overview of the matrix is informed by existing models and concepts that address one of more of the C's and the A's. This gives us a unique opportunity to take stock of what has been studied so far and, toward the end, consider new avenues for the development of theory and research agendas within creativity studies. 相似文献
69.
70.