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   1542784篇
  免费   103811篇
  国内免费   3281篇
耳鼻咽喉   22456篇
儿科学   46799篇
妇产科学   42785篇
基础医学   216644篇
口腔科学   44708篇
临床医学   129079篇
内科学   307680篇
皮肤病学   35765篇
神经病学   124682篇
特种医学   59809篇
外国民族医学   529篇
外科学   234104篇
综合类   31916篇
现状与发展   6篇
一般理论   488篇
预防医学   111141篇
眼科学   35378篇
药学   114528篇
  4篇
中国医学   3608篇
肿瘤学   87767篇
  2018年   18393篇
  2017年   13936篇
  2016年   14905篇
  2015年   16748篇
  2014年   21726篇
  2013年   33460篇
  2012年   47384篇
  2011年   49285篇
  2010年   27903篇
  2009年   25559篇
  2008年   45952篇
  2007年   49832篇
  2006年   49435篇
  2005年   48060篇
  2004年   46354篇
  2003年   44371篇
  2002年   43259篇
  2001年   68689篇
  2000年   70524篇
  1999年   59997篇
  1998年   15414篇
  1997年   14093篇
  1996年   13531篇
  1995年   12768篇
  1994年   11939篇
  1992年   45409篇
  1991年   43635篇
  1990年   42834篇
  1989年   41636篇
  1988年   38963篇
  1987年   38259篇
  1986年   36658篇
  1985年   34670篇
  1984年   25994篇
  1983年   22050篇
  1982年   13238篇
  1981年   12019篇
  1979年   24924篇
  1978年   17779篇
  1977年   15496篇
  1976年   13924篇
  1975年   15922篇
  1974年   18899篇
  1973年   18421篇
  1972年   17612篇
  1971年   16528篇
  1970年   15670篇
  1969年   15148篇
  1968年   14165篇
  1967年   12611篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
71.
目的:评价东部身体-智力-精神(EBMS)群体干预对进行体外受精(IVF)的中国妇女焦虑缓解的作用。设计:随机对照研究。机构:三级辅助生殖机构。受试者:227例接受第1个IVF周期治疗的妇女。干预:干预组(n=69)接受4次EBMS群体咨询,而对照组(n=115)无任何干预。主要观察指标:状态-特质焦虑问卷。结果:与对照组相比,干预组在干预后状态焦虑平均分显著下降。每组移植同样数目的卵子,但干预组没有明显更高妊娠率的倾向。  相似文献   
72.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
73.
Severe adverse effects during the use of ovulation inhibitors occur mostly in women who have an elevated risk for the development of certain diseases owing to hereditary or acquired factors. By means of a careful personal or family history analysis as well as specific laboratory examinations, an existing predisposition may frequently be diagnosed and the individual risk associated with the use of oral contraceptive inhibitors may be estimated. The present contribution describes the potential effects of treatment with ovulation inhibitors on women with thrombophilia, cardiovascular disease, diabetes mellitus, dyslipidemia, overweight or underweight, tumors, psychiatric and neurological diseases and autoimmune disease. The hormonal methods and non-hormonal alternatives available for contraception are elucidated according to existing lesions and risk factors and the advantages and disadvantages are discussed.  相似文献   
74.
The new treatment strategy for Peritoneal Surface Malignancy combines a cytoreductive surgery and perioperative intraperitoneal chemotherapy. Cytoreduction removes all macroscopic tumor. Intraperitoneal chemotherapy avoids implantation of microscopic residual tumor cells on intra-abdominal surfaces when it is administered intraoperatively and/or early in the postoperative period. Delivering cytotoxic drugs directly into the peritoneal cavity maximizes dose intensity and minimizes systemic toxicity. Hyperthermia is selectively cytotoxic for malignant cells and potentiates the effect of chemotherapy. Implementation of this procedure makes the perioperative personnel to face a risk of exposure to cytotoxic agents. Furthermore, peritonectomies and electro-evaporation of tumor nodules are performed with high voltage electrocautery, generating a large amount of surgical smoke during several hours. Inhalation of these fumes may be also a risk for healthcare workers. In this article, we analyse in depth these new risks of the operating room personnel, we review the literature, and we give guidelines for secure performance of cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy, as well as for early postoperative intraperitoneal chemotherapy administration. These new procedures are safe techniques for patients and healthcare workers provided adequate policies are adopted to avoid occupational exposure.  相似文献   
75.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
76.
77.
78.
79.
80.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  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