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   7039篇
  免费   490篇
  国内免费   16篇
耳鼻咽喉   43篇
儿科学   248篇
妇产科学   280篇
基础医学   976篇
口腔科学   140篇
临床医学   874篇
内科学   1122篇
皮肤病学   79篇
神经病学   588篇
特种医学   154篇
外科学   867篇
综合类   104篇
一般理论   4篇
预防医学   887篇
眼科学   149篇
药学   426篇
中国医学   12篇
肿瘤学   592篇
  2023年   49篇
  2022年   59篇
  2021年   151篇
  2020年   86篇
  2019年   135篇
  2018年   150篇
  2017年   90篇
  2016年   128篇
  2015年   115篇
  2014年   169篇
  2013年   298篇
  2012年   420篇
  2011年   456篇
  2010年   227篇
  2009年   212篇
  2008年   381篇
  2007年   413篇
  2006年   382篇
  2005年   315篇
  2004年   347篇
  2003年   290篇
  2002年   249篇
  2001年   130篇
  2000年   125篇
  1999年   107篇
  1998年   61篇
  1997年   48篇
  1996年   52篇
  1995年   62篇
  1994年   51篇
  1993年   41篇
  1992年   130篇
  1991年   115篇
  1990年   130篇
  1989年   97篇
  1988年   99篇
  1987年   112篇
  1986年   67篇
  1985年   106篇
  1984年   79篇
  1983年   73篇
  1982年   46篇
  1981年   44篇
  1980年   52篇
  1979年   88篇
  1978年   58篇
  1977年   35篇
  1972年   38篇
  1970年   45篇
  1967年   36篇
排序方式: 共有7545条查询结果,搜索用时 15 毫秒
81.
82.
83.
Forty-four patients, ASA physical status I or II, undergoing thiamylal, fentanyl, N2O/O2 anaesthesia were studied to determine the dose-response to succinylcholine (Sch) without prior defasciculation (24 pt - Group 1), or three minutes following d-tubocurarine (dTC), 0.043 mg.kg-1 (20 pt - Group 2). The individual log dose-logit response curve for each patient was determined using a cumulative dose plus infusion technique and integrated EMG monitoring of the first dorsal interosseous muscle. The mean (+/- SEM) ED50, ED90 and ED95 values for Sch in Group 1 were 0.13 +/- 0.01, 0.19 +/- 0.01 and 0.22 +- 0.01 mg.kg-1, and in Group 2 were 0.16 +/- 0.01, 0.25 +/- 0.01 and 0.29 +/- 0.02 mg.kg-1, respectively. The mean ED values in Group 2 were significantly greater than the equivalent values in Group 1 (P less than 0.05). Compared with values in Group 1, ED values in Group 2 represented mean increases of 23, 32, and 32 per cent, respectively. These pharmacodynamic data indicate that the dose of Sch needs to be increased by 32 per cent following a defasciculating dose of dTC 3 mg.70 kg-1 (0.043 mg.kg-1).  相似文献   
84.
85.
OBJECTIVES. To describe a theoretic approach and rationale for the integration of health protection and health promotion in worksite cancer prevention programs and to describe an intervention study designed to implement this integration. METHODS. Twenty-four worksites were recruited to participate in this randomized, controlled study. The theoretically based intervention model integrates health promotion and health protection through (1) joint worker-management participation in program planning and implementation, (2) consultation on worksite changes, and (3) educational programs targeting health behavior change. RESULTS. Although the primary purpose of this paper is to describe a theoretic approach to the integration of health promotion and health protection, preliminary results are also noted. In these predominantly manufacturing worksites, many workers faced the double jeopardy of exposures to occupational carcinogens and personal risks such as smoking or poor dietary habits. Production workers' job responsibilities frequently limited their full participation. Barriers to participation were identified early in the project, and strategies were developed to facilitate maximal worker involvement and worksite changes. CONCLUSIONS. Lifestyle changes such as smoking cessation or dietary changes may be more effectively promoted among blue collar audiences when programs also encourage management actions to reduce occupational exposures. Public health professionals trained in health promotion and health protection must work together to effectively address the health concerns of this population.  相似文献   
86.
87.
Rationale: A novel scheme for the synthesis of cocaine analogs from vinylcarbenoid precursors has made available compounds that have a diverse range of affinities for the DA and 5-HT transporters. These compounds were used to explore the relationship between their biochemical properties and their reinforcing effects. Objectives: The objective was to assess the reinforcing efficacy of selected cocaine analogs and compare the results with their selectivity in binding to DA and 5-HT transporters. Methods: Rats were prepared with chronically indwelling intravenous cannulae and trained to self-administer cocaine on a progressive ratio (PR) schedule. A range of doses of seven cocaine analogs were substituted for cocaine in separate groups of animals. Results: The results demonstrate a wide range of reinforcing efficacies and potencies among the seven selected drugs. Four tropane analogs (WF-11, WF-23, WF-24, WF-55) were found to support self-administration behavior on a PR schedule while three did not (WF-31, WF-54 and WF-60). The DA/5-HT selectivity ratio was found to be a better predictor of self-administration behavior than affinity at the DA transporter alone. Conclusion: These data suggest that drugs with a higher affinity for the DA versus the 5-HT transporter are more likely to be self-administered. Received: 29 October 1998 / Final version: 5 February 1999  相似文献   
88.
This article details a practice protocol for the examination and reporting of specimens removed from patients with carcinoma of the urinary bladder, ureter, renal pelvis, or urethra. It was created by a multidisciplinary task force of pathologists and oncologists established by the Cancer Committee of the College of American Pathologists. Documentation for the protocol was obtained from the previously published protocol, the medical literature, personal experience, and consultation with colleagues. After creation and review by the task force, the protocol was sent to 1000 randomly selected practicing pathologists as a survey. Their comments and suggestions were addressed in the final version. The protocol was approved by the Board of Governors of the College of American Pathologists.  相似文献   
89.
90.
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