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   22378篇
  免费   2061篇
  国内免费   31篇
耳鼻咽喉   256篇
儿科学   707篇
妇产科学   665篇
基础医学   2975篇
口腔科学   347篇
临床医学   2333篇
内科学   3901篇
皮肤病学   445篇
神经病学   2197篇
特种医学   814篇
外科学   2974篇
综合类   334篇
一般理论   27篇
预防医学   3054篇
眼科学   530篇
药学   1355篇
  1篇
中国医学   17篇
肿瘤学   1538篇
  2023年   351篇
  2022年   527篇
  2021年   1048篇
  2020年   608篇
  2019年   945篇
  2018年   1010篇
  2017年   684篇
  2016年   706篇
  2015年   702篇
  2014年   891篇
  2013年   1132篇
  2012年   1631篇
  2011年   1620篇
  2010年   811篇
  2009年   735篇
  2008年   1185篇
  2007年   1099篇
  2006年   965篇
  2005年   891篇
  2004年   750篇
  2003年   650篇
  2002年   563篇
  2001年   327篇
  2000年   318篇
  1999年   271篇
  1998年   150篇
  1997年   136篇
  1996年   135篇
  1995年   144篇
  1994年   115篇
  1993年   109篇
  1992年   229篇
  1991年   206篇
  1990年   190篇
  1989年   215篇
  1988年   152篇
  1987年   189篇
  1986年   167篇
  1985年   181篇
  1984年   145篇
  1983年   123篇
  1982年   108篇
  1981年   64篇
  1980年   75篇
  1979年   117篇
  1978年   75篇
  1977年   73篇
  1976年   65篇
  1974年   75篇
  1973年   73篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
ABSTRACT: This study obtained input from Australian student smokers approximately 15 years old, which may be useful in designing school-based smoking cessation programs. The sample was analyzed by previous quitting experience and intentions to quit. The order of preference for assistance options and incentives for quitting was similar across all groups: however, those who previously attempted to quit (previous quitters) and those who intended to quit (intenders) in the future were significantly more likely than non-quitters and non-intenders to find assistance options for quitting acceptable. The potential for saving money emerged as an important variable in convincing all groups of smokers not to smoke, and using personal willpower and cutting down slowly were identified as important in actual attempts to quit. The need for programs to be free and for friends to be supportive also was evident across all groups.  相似文献   
24.

Background  

Many studies have found socioeconomic differentials in cancer survival. Previous studies have generally demonstrated poorer cancer survival with decreasing socioeconomic status but mostly used only ecological measures of status and analytical methods estimating simple survival. This study investigate socio-economic differentials in cancer survival using four indicators of socioeconomic status; three individual and one ecological. It uses a relative survival method which gives a measure of excess mortality due to cancer.  相似文献   
25.
The effects of acetazolamide, calcitonin (CT), and parathyroid hormone (PTH) on acid production in isolated osteoclasts has been investigated. Osteoclasts were isolated from the endosteum of 3-week chick tibias and were maintained under culture conditions for 5 days. The cells were treated with acetazolamide (10 x 4 M and 10(-7) M), CT (1 mU/ml and 0.31 mU/ml) and PTH (6.5 U/ml and 0.40 U/ml) for 1, 3, 6, and 18 hr. The cells were stained with acridine orange and the intensity of fluorescence measured by a light microscope photometer. Acetazolamide treatment resulted in a steady decline in intracellular acidity, suggesting that carbonic anhydrase plays a major role in acid production in isolated osteoclasts. Treatment with PTH produced a decline in acidity at 1 hr, followed by a peak at 3 hr and then a decline at 6 and 18 hr. The transient increase in acidity may be due to activation of carbonic anhydrase by PTH. Calcitonin treatment also resulted in a decline in cell acidity which was similar, but less pronounced than that resulting from acetazolamide treatment. These results indicate that calcitonin may mediate osteoclast activity by alterations in intracellular acid production.  相似文献   
26.
Gynecologists have found the argon and CO2 lasers very valuable for performance of pelviscopic surgery. Their interest was born from the complications initially seen with electrosurgical pelviscopic procedures and from the unique features of the laser for treatment of endometriosis. Laser technology was applied to laparoscopic cholecystectomy from its inception. This article reviews the arguments for laser and electrosurgical use in the many laparoscopic procedures--established and in evolution.  相似文献   
27.
K L Reuter  T Griffin  R E Hunter 《Cancer》1989,63(6):1123-1128
In 35 women with epithelial carcinoma of the ovary, the results of restaging laparotomy were compared with the preoperative abdominopelvic computed tomography (CT) findings to evaluate the accuracy of CT for determining tumor status. In the 36 studies performed, enhanced CT scans at 10-mm to 15-mm intervals had a sensitivity of 84% and a specificity of 88%; in addition, there was 86% agreement between the CT and surgical findings. These results suggest that although CT is not accurate enough to completely replace the restaging laparotomy, its high accuracy in determining residual disease after treatment is helpful for patient management.  相似文献   
28.
OBJECTIVES: The Women's Health Questionnaire (WHQ) includes 36 items assessing nine domains of physical and emotional experiences of mid-aged women. The primary aim of the current research was to examine the psychometric properties of the WHQ across linguistic versions in view of the increased need for reliable health-related quality of life (HRQL) measures in multinational studies. METHODS: In this paper, we examine the hypothesized structure of the questionnaire in a UK sample, to develop and verify a revised model to be used in multicenter, international studies. RESULTS AND CONCLUSIONS: Content analysis and evaluation of missing data led to exclusion of 'Menstrual symptoms' and 'Sexual behavior' domains, retaining these as optional modules of the core questionnaire. Additionally, item 13 was excluded because it does not investigate the same concepts as other domains and the deletion of five additional items appeared to improve the questionnaire's factor structure. The revised WHQ comprises 23 items, investigating six domains. The cross-sectional psychometric properties of the 23-item WHQ were good and better than those of the 36-item version. The 23-item WHQ was assessed with multinational data, to evaluate cross-cultural equivalence of linguistically adapted versions. In addition, its reproducibility and responsiveness need to be documented.  相似文献   
29.
30.
We describe a model of how physician assistants can be used in an academic medical center to expand radiologist productivity, and to enhance the departmental academic and educational missions. At Harborview Medical Center, following a training program and graduated responsibility under supervision, physician assistants provide initial interpretation of radiology studies, consultation to referring physicians, and perform less complicated interventional procedures. Acceptance of physician assistants by the radiologists, radiology residents, and referring physicians has been high. Although the impact of physician assistants on departmental clinical productivity is difficult to measure, our data suggest that radiologists are more efficient when physician assistants are assigned to service, both in terms of numbers of studies interpreted, and timeliness of reporting and billing. As a result of the success of our program, we believe that physician assistants can have an important role in radiology practice.  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