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   21477篇
  免费   1240篇
  国内免费   187篇
耳鼻咽喉   141篇
儿科学   1240篇
妇产科学   325篇
基础医学   2604篇
口腔科学   393篇
临床医学   1316篇
内科学   3738篇
皮肤病学   420篇
神经病学   1331篇
特种医学   1108篇
外国民族医学   5篇
外科学   2858篇
综合类   832篇
一般理论   1篇
预防医学   1434篇
眼科学   1078篇
药学   2060篇
  6篇
中国医学   307篇
肿瘤学   1707篇
  2022年   272篇
  2021年   411篇
  2020年   281篇
  2019年   307篇
  2018年   374篇
  2017年   308篇
  2016年   373篇
  2015年   423篇
  2014年   618篇
  2013年   805篇
  2012年   1125篇
  2011年   1150篇
  2010年   699篇
  2009年   589篇
  2008年   952篇
  2007年   979篇
  2006年   906篇
  2005年   863篇
  2004年   770篇
  2003年   774篇
  2002年   715篇
  2001年   633篇
  2000年   643篇
  1999年   585篇
  1998年   320篇
  1997年   296篇
  1996年   274篇
  1995年   247篇
  1994年   183篇
  1993年   211篇
  1992年   367篇
  1991年   397篇
  1990年   371篇
  1989年   442篇
  1988年   334篇
  1987年   352篇
  1986年   296篇
  1985年   335篇
  1984年   266篇
  1983年   235篇
  1982年   156篇
  1981年   146篇
  1980年   143篇
  1979年   192篇
  1978年   141篇
  1977年   129篇
  1975年   154篇
  1974年   143篇
  1973年   136篇
  1971年   142篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Isolated patellofemoral arthritis is an increasingly recognized entity, and is usually associated with previous patellofemoral dysplasia or instability. Patellofemoral arthroplasty (PFA) has evolved significantly in recent years, both in terms of implant design and importantly in the understanding of appropriate patient selection. This review outlines the indications and investigations for PFA, provides a brief history of the development of contemporary implants, and presents the clinical outcomes for the prostheses most commonly used in the UK. In addition, it provides a detailed surgical technique for implantation of an onlay implant, with tips on how to optimize patellofemoral biomechanics and thus achieve a consistently good outcome.  相似文献   
2.
3.
4.

Objective

Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.

Methods

Heart transplants were performed after 6 hours of cold ischemic storage. Recipient pigs were randomized to treatment with or without HTS (7.5% NaCl) before cardiopulmonary bypass (CPB). Using a myograft apparatus, coronary artery endothelial-dependent (Edep) and -independent (Eind) relaxation was assessed. LV performance was determined using pressure-volume loop analysis. Pulmonary interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α expression was measured.

Results

Weaning from CPB and LV performance after transplantation were improved in HTS-treated animals. Successful weaning from CPB was greater in the HTS-treated hearts (8 of 8 vs 2 of 8; P < .05). Mean LV functional recovery was improved in the HTS-treated animals, as assessed by preload recruitable stroke work (65 ± 10% vs 27 ± 10%; P < .001) and end-systolic elastance (55 ± 7% vs 37 ± 4%; P < .001). Treatment with HTS resulted in improved Edep (mean maximum elastance [Emax], 56 ± 5% vs 37 ± 7%; P < .001) and Eind (mean Emax%, 77 ± 6% vs 52 ± 4%; P < .001) vasorelaxation compared with control. Pulmonary expression of IL-2, IL-6, and TNF-α increased following transplantation, whereas HTS therapy attenuated IL production (P < .001). Transplantation increased plasma TNF-α levels and LV TNF-α expression, whereas HTS prevented this up-regulation (P < .001).

Conclusions

Recipient HTS pretreatment preserves allograft vasomotor and LV function, and HTS therapy limits CPB-induced injury. HTS may be a novel recipient intervention to prevent graft dysfunction.  相似文献   
5.
6.
Endoscopic clips have been used mainly for control of gastrointestinal (GI) bleeding and occasionally for closure of GI perforations. However, closure of spontaneous esophageal perforation (Boerhaave's syndrome) by clipping has not been reported. We described successful non-surgical closure of spontaneous esophageal perforation by endoscopic clipping in a patient with bilateral pyopneumothorax and septicemia.  相似文献   
7.
Both ultrashort echo-time STEAM and MEGA-PRESS-edited spectroscopy were used to validate noninvasive quantification of vitamin C (ascorbate) in the developing rat brain, where changes in ascorbate concentration have been reported. Despite strong overlap with resonances from glutamine, glutamate, glutathione, and macromolecules, reliable quantification of ascorbate (Cramer-Rao lower bounds<0.2 micromol/g) by LCModel analysis of STEAM (TE=2 ms) spectra was possible at 9.4 T. Ascorbate concentrations quantified from the STEAM spectra were in very good agreement with concentrations calculated from fully resolved ascorbate resonances in MEGA-PRESS-edited spectra measured from identical volumes of interest. Ascorbate concentrations measured using STEAM decreased with increasing postnatal rat age, in agreement with published brain ascorbate concentrations measured in vitro using high-performance liquid chromatography (HPLC).  相似文献   
8.
BACKGROUND: Abnormalities in calcium and vitamin D metabolism have been reported after bariatric surgery. The purpose of this study was to evaluate vitamin D nutritional status among morbidly obese patients before gastric bypass surgery. METHODS: We prospectively studied 279 morbidly obese patients seeking gastric bypass surgery for vitamin D nutritional status as assessed by serum 25-hydroxyvitamin D level. In addition, serum samples were analyzed for calcium, alkaline phosphatase (AP), intact parathyroid hormone (PTH), and 1,25-dihydroxyvitamin D. RESULTS: Mean patient age was 43 +/- 9 years; 87% of the study patients were women, and 72% were white. Serum calcium and AP levels were normal in 88% and 89% of the patients, respectively. Vitamin D depletion, defined as serum 25-hydroxyvitamin D level 相似文献   
9.
10.
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