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   1933128篇
  免费   167635篇
  国内免费   5118篇
耳鼻咽喉   28725篇
儿科学   63694篇
妇产科学   52478篇
基础医学   259035篇
口腔科学   53264篇
临床医学   180793篇
内科学   398931篇
皮肤病学   46228篇
神经病学   160800篇
特种医学   76028篇
外国民族医学   558篇
外科学   304608篇
综合类   40754篇
现状与发展   75篇
一般理论   598篇
预防医学   147398篇
眼科学   43465篇
药学   136090篇
  3篇
中国医学   3563篇
肿瘤学   108793篇
  2021年   15797篇
  2019年   15730篇
  2018年   27671篇
  2017年   22320篇
  2016年   24345篇
  2015年   26997篇
  2014年   39365篇
  2013年   53064篇
  2012年   61421篇
  2011年   63603篇
  2010年   42456篇
  2009年   43206篇
  2008年   60155篇
  2007年   61648篇
  2006年   63658篇
  2005年   59778篇
  2004年   57714篇
  2003年   53864篇
  2002年   52530篇
  2001年   83572篇
  2000年   85626篇
  1999年   73369篇
  1998年   21736篇
  1997年   19999篇
  1996年   19802篇
  1995年   19375篇
  1994年   17207篇
  1993年   15970篇
  1992年   58936篇
  1991年   57175篇
  1990年   55530篇
  1989年   53768篇
  1988年   49935篇
  1987年   49018篇
  1986年   46672篇
  1985年   44943篇
  1984年   33589篇
  1983年   28955篇
  1982年   17103篇
  1979年   31663篇
  1978年   22017篇
  1977年   18737篇
  1976年   17396篇
  1975年   18440篇
  1974年   22478篇
  1973年   21643篇
  1972年   19882篇
  1971年   18669篇
  1970年   17198篇
  1969年   16035篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
104.
105.
106.
107.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
108.
The absence of the temporary incisors could be to a genetic illness or to some multiple premature extractions. These extractions are the aftermaths of the carious lesions or some traumatisms underwent by the temporary incisors. Beyond measure the loss of the space, the premature loss some temporary incisors very often assign the relational development of the child and disturb its psychological development and the aesthetic function. Across some cases clinics, the authors show that the replacement of the temporary incisors is the therapeutic ideal solution. Indeed, the child prosthesis, replacing the temporary absent incisors, solves the psychological, aesthetic and relational problems of the child.  相似文献   
109.
BACKGROUND: Despite major improvement in surgical techniques and intensive care management, stroke remains one of the most devastating complications of coronary artery bypass grafting (CABG). We aimed to determine factors predicting the occurrence of stroke during CABG. A special interest was focused on preoperative therapies. METHODS: We prospectively enrolled 810 consecutive candidates for CABG alone in a specific database, including all pre- and perioperative data (history, clinical, therapeutic, cardiac catheterization, surgical and intensive care data). Univariate tests and then multiple logistic regression analysis were used to determine independent predictive factors. RESULTS: During the first postoperative month, stroke occurred in 11 cases and transient ischemic attack (TIA) in 4 additive cases (cumulative rate: 1.85%). After the multivariate analysis, the following factors remained significant (p<0.05) in the predictive model, with corresponding odds ratios between brackets: redo cardiac surgery (7.45), unstable cardiac status (4.74), past history of cerebrovascular disease (4.14), past history of peripheral arterial disease (3.55), whereas the presence of preoperative statins was protective (0.24, 95% IC: 0.07-0.78). The addition of perioperative data (aortic calcification, postoperative arrhythmia, on/off-pump surgery) did not change the final predictive model. CONCLUSION: To our knowledge, this is the first real-world observational report highlighting the interest of statins for the prevention of stroke in the very special situation of CABG. Even though according to randomized trials coronary patients have a benefit from these drugs, a special level of interest should be directed towards those presenting the above-mentioned risk factors.  相似文献   
110.
背景:针对糖尿病患者Lp(a)水平和冠状动脉疾病(CAD)严重程度之间关系的研究较少并且结论有争议。另外,目前尚无关于apo(a)多态性与上述疾病关系的研究。本研究旨在探讨大样本2型糖尿病患者中冠状动脉粥样硬化的程度与Lp(a)水平及apo(a)多态性的相关性。方法:连续选取227例2型糖  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