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   23145篇
  免费   1339篇
  国内免费   210篇
耳鼻咽喉   178篇
儿科学   1317篇
妇产科学   354篇
基础医学   2737篇
口腔科学   472篇
临床医学   1474篇
内科学   4152篇
皮肤病学   458篇
神经病学   1522篇
特种医学   843篇
外国民族医学   5篇
外科学   3176篇
综合类   905篇
一般理论   1篇
预防医学   1547篇
眼科学   1152篇
药学   2231篇
  5篇
中国医学   319篇
肿瘤学   1846篇
  2023年   124篇
  2022年   301篇
  2021年   479篇
  2020年   326篇
  2019年   356篇
  2018年   448篇
  2017年   382篇
  2016年   434篇
  2015年   492篇
  2014年   704篇
  2013年   958篇
  2012年   1308篇
  2011年   1331篇
  2010年   804篇
  2009年   656篇
  2008年   1099篇
  2007年   1130篇
  2006年   1016篇
  2005年   965篇
  2004年   862篇
  2003年   856篇
  2002年   796篇
  2001年   644篇
  2000年   649篇
  1999年   590篇
  1998年   308篇
  1997年   277篇
  1996年   244篇
  1995年   218篇
  1994年   184篇
  1993年   196篇
  1992年   372篇
  1991年   402篇
  1990年   378篇
  1989年   427篇
  1988年   319篇
  1987年   335篇
  1986年   263篇
  1985年   277篇
  1984年   245篇
  1983年   220篇
  1982年   142篇
  1981年   132篇
  1979年   192篇
  1978年   127篇
  1975年   141篇
  1974年   146篇
  1973年   141篇
  1972年   128篇
  1971年   144篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.

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   
4.
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.
A 17-year-old man presented with signs of peritonitis. Laparotomy revealed gangrene of the stomach without obvious cause. The patient underwent total gastrectomy with esophago-jejunal anastomosis with formation of jejunal pouch. Bacterial culture of the peritoneal fluid grew Strept. pyogenes and E. coli. The patient was discharged on day 21 after a stormy postoperative course.  相似文献   
9.
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   
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