首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   64421篇
  免费   2465篇
  国内免费   31篇
  66917篇
  2020年   682篇
  2019年   892篇
  2018年   1207篇
  2017年   1323篇
  2016年   1284篇
  2015年   924篇
  2014年   1095篇
  2013年   5058篇
  2012年   1968篇
  2011年   2075篇
  2010年   1341篇
  2009年   1316篇
  2008年   1877篇
  2007年   1837篇
  2006年   1661篇
  2005年   1451篇
  2004年   1357篇
  2003年   1357篇
  2002年   1307篇
  2001年   2109篇
  2000年   2043篇
  1999年   1554篇
  1998年   696篇
  1997年   633篇
  1996年   607篇
  1994年   607篇
  1992年   1310篇
  1991年   1204篇
  1990年   1224篇
  1989年   1107篇
  1988年   1111篇
  1987年   1070篇
  1986年   1063篇
  1985年   1069篇
  1984年   906篇
  1983年   791篇
  1982年   603篇
  1979年   957篇
  1978年   704篇
  1977年   632篇
  1975年   797篇
  1974年   852篇
  1973年   940篇
  1972年   741篇
  1971年   669篇
  1970年   621篇
  1969年   690篇
  1968年   791篇
  1967年   717篇
  1966年   701篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Book reviews     
Arnold, M. Memory and the brain. Hillsdale, N. J.: Lawrence Erlbaum Associates. 1984. Pp. 532. ISBN 0-89859-290-9. £47.90.

Green, T. R. G., Payne, S. P. and van der Veer, G. C. (Eds.). The psychology of computer use.. London: Academic Press. 1983. Pp. 225. ISBN 0-12-2974204. $9.50.

Stunkard, A. J. and Stellar, E. (Eds.). Eating and its disorders. New York: Raven Press. 1984. Pp. 302. ISBN 0-89004-891-6. $58.50.

Spillmann, L. and Wooten, B. R. (Eds.) Sensory experience, adaptation, and perception: Festschrift for Zero Kohler. Hillsdale, N. J.: Lawrence Erlbaum Associates. 1984. Pp. xxvii + 748. ISBN 0 8985-3-218-6. £70.85.

Geschwind, N. and Galaburda, A. M. (Eds.)Cerebral dominance: The biological foundations. Cambridge, Mass.: Harvard University Press. 1984. Pp. 232. ISBN 0-674-10658-X. £24.35.

Annett, M. Left, right, hand and brain: The right shift theory. 1985. London and Hillsdale, N. J.: Lawrence Erlbaum Associates. Pp. xiii + 474. ISBN 0-86377418-5 £29.95.

Ericsson, K. A. and Simon, H. A. Protocol analysis: Verbal reports as data. Cambridge, Mass.: The M.I.T. Press. 1984. Pp. 426. ISBN 0-262-05029-3. £28.95.  相似文献   
22.
OBJECTIVE: Compare the efficacy of a multicomponent social support intervention to standard-of-care counseling on medication adherence among HIV-infected patients initiating antiretroviral therapy. DESIGN: Randomized controlled trial. Generalized estimating equations tested for differences in the percentage of participants achieving 90% adherence. MAIN OUTCOME MEASURES: Pill-taking, electronically monitored over 6 consecutive months; plasma viral load (VL), assessed at 3 and 6 months following initiation of therapy. RESULTS: Of 226 participants who were randomized and began the trial, 87 (38%) were lost to the study by 6 months. The proportion of adherent participants declined steadily over time, with no time by group interaction. Sustained adherence was associated with increased odds of achieving an undetectable VL (OR=1.78; 95% CI=1.01, 3.13). In intention-to-treat analyses, a larger proportion of the intervention group than the control group was adherent (40.15% vs. 27.59%, p=.02) and achieved an undetectable VL p=.04). However, the majority of participants who remained on study experienced some reduction in VL (>or=1-log drop or undetectable), regardless of experimental condition. CONCLUSION: The multicomponent social support intervention significantly improved medication adherence over standard-of-care counseling; evidence for improved virologic outcomes was inconsistent. Early discontinuation of care and treatment may be a greater threat to the health of HIV patients than imperfect medication-taking.  相似文献   
23.
Although perceived health risk plays a prominent role in theories of health behavior, its empirical role in risk taking is less clear. In Study 1 (N = 129), 2 measures of drivers' risk-taking behavior were found to be unrelated to self-estimates of accident concern but to be related to self-ratings of driving skill and the perceived thrill of driving. In Study 2 (N = 405), out of a wide range of potential influences, accident concern had the weakest relationship with risk taking. The authors concluded that although health risk is a key feature in many theories of health behavior and a central focus for researchers and policy makers, it may not be such a prominent factor for those actually taking the risk.  相似文献   
24.
The authors used recursive partitioning methods to identify combinations of baseline characteristics that predict 2-year physical activity success in each of 3 physical activity interventions delivered in the multisite Activity Counseling Trial. The sample consisted of 874 initially sedentary primary care patients, ages 35-75 years, who were at risk for cardiovascular disease. Predictors of 2-year success were specific to each intervention and represented a range of domains, including physiological, demographic, psychosocial, health-related, and environmental variables. The results indicate how specific patient subgroups (e.g., obese, unfit individuals; high-income individuals in stable health) may respond differently to varying levels and amounts of professional assistance and support. The methods used provide a practical first step toward identifying clinically meaningful patient subgroups for further systematic investigation.  相似文献   
25.
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.  相似文献   
26.
27.
28.
29.
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   
30.
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   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号