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   9282篇
  免费   482篇
  国内免费   22篇
耳鼻咽喉   128篇
儿科学   615篇
妇产科学   138篇
基础医学   818篇
口腔科学   178篇
临床医学   751篇
内科学   2523篇
皮肤病学   235篇
神经病学   503篇
特种医学   239篇
外科学   1271篇
综合类   205篇
预防医学   405篇
眼科学   349篇
药学   556篇
中国医学   16篇
肿瘤学   856篇
  2023年   45篇
  2022年   100篇
  2021年   288篇
  2020年   138篇
  2019年   187篇
  2018年   274篇
  2017年   146篇
  2016年   163篇
  2015年   191篇
  2014年   284篇
  2013年   350篇
  2012年   534篇
  2011年   555篇
  2010年   313篇
  2009年   222篇
  2008年   426篇
  2007年   488篇
  2006年   458篇
  2005年   407篇
  2004年   400篇
  2003年   335篇
  2002年   331篇
  2001年   267篇
  2000年   239篇
  1999年   217篇
  1998年   101篇
  1997年   54篇
  1996年   47篇
  1995年   63篇
  1993年   43篇
  1992年   168篇
  1991年   172篇
  1990年   169篇
  1989年   151篇
  1988年   141篇
  1987年   129篇
  1986年   112篇
  1985年   106篇
  1984年   105篇
  1983年   74篇
  1982年   51篇
  1981年   42篇
  1980年   39篇
  1979年   84篇
  1978年   40篇
  1977年   62篇
  1974年   49篇
  1972年   48篇
  1970年   43篇
  1969年   38篇
排序方式: 共有9786条查询结果,搜索用时 15 毫秒
91.
A case is described of psychotic depression that worsened during a course of three bilateral ECTs per week, but responded to administration of two bilateral ECTs three times per week. For some patients, ECTs may need to be given more than three times per week to obtain remission.  相似文献   
92.
Neurosurgical Review - Unruptured intracranial saccular aneurysms occur in 3–5% of the general population. As the use of diagnostic medical imaging has steadily increased over the past few...  相似文献   
93.
94.
Desensitization has enabled incompatible living donor kidney transplantation (ILDKT) across HLA/ABO barriers, but added immunomodulation might put patients at increased risk of infections. We studied 475 recipients from our center from 2010 to 2015, categorized by desensitization intensity: none/compatible (n = 260), low (0-4 plasmaphereses, n = 47), moderate (5-9, n = 74), and high (≥10, n = 94). The 1-year cumulative incidence of infection was 50.1%, 49.8%, 66.0%, and 73.5% for recipients who received none, low, moderate, and high-intensity desensitization (P < .001). The most common infections were UTI (33.5% of ILDKT vs. 21.5% compatible), opportunistic (21.9% vs. 10.8%), and bloodstream (19.1% vs. 5.4%) (P < .001). In weighted models, a trend toward increased risk was seen in low (wIRR = 0.771.402.56,P = .3) and moderately (wIRR = 0.881.352.06,P = .2) desensitized recipients, with a statistically significant 2.22-fold (wIRR = 1.332.223.72,P = .002) increased risk in highly desensitized recipients. Recipients with ≥4 infections were at higher risk of prolonged hospitalization (wIRR = 2.623.574.88, P < .001) and death-censored graft loss (wHR = 1.154.0113.95,P = .03). Post–KT infections are more common in desensitized ILDKT recipients. A subset of highly desensitized patients is at ultra-high risk for infections. Strategies should be designed to protect patients from the morbidity of recurrent infections, and to extend the survival benefit of ILDKT across the spectrum of recipients.  相似文献   
95.
Recent studies have established that mucosal butyrate stimulates electroneutral sodium-chloride (NaCl) absorption in the distal colon of the rat and a model in which Na-hydrogen (H) and Cl-butyrate exchanges are coupled has been proposed as the mechanism of butyrate-dependent electroneutral Na-Cl absorption. These studies were designed to examine butyrate-dependent electroneutral Na-Cl absorption in experimental conditions in which HCO3-dependent electroneutral Na-Cl absorption is inhibited: in Na-depleted (aldosterone-treated) animals and in the presence of increased mucosal cyclic adenosine monophosphate (AMP). Butyrate-dependent electroneutral Na-Cl absorption was markedly reduced in Na-depleted rats. In contrast, the inhibition of both net Na and net Cl absorption by 5 mM serosal theophylline was significantly less in butyrate-containing, HCO3-free Ringer solution than in butyrate-free-HCO3-containing Ringer solution. These studies indicate that cyclic AMP does not inhibit butyrate-dependent electroneutral Na-Cl absorption and we propose that the mechanism of cyclic AMP inhibition of HCO3-dependent electroneutral Na-Cl absorption may be a result of its inhibition of Cl-HCO3, not Na-H exchange.  相似文献   
96.
97.
Retropharyngeal cystic hygroma is a rare condition and needs to be differentiated from common clinical condition of retropharyngeal abscess. Two such cases are discussed in the present report.  相似文献   
98.
99.
100.
Epidermal growth factor (EGF) is considered to be mitogenic for proliferation of mammary glands in animals. The action of EGF is mediated by specific EGF receptors (EFG-R). In the present study, we investigated distribution of EGF receptors during various physiological stages of mammary glands, N-methyl-N-nitrosourea (MNU)-induced mammary tumors in rats and human breast cancer samples. EGF receptor concentrations were determined by Scatchard analyses in the membrane fraction of the tissues. Results showed increased EGF receptor levels in the structurally differentiated mammary tissues from pregnant rats; whereas lower concentrations were observed in the functionally differentiated glands from lactating rats. EGF receptors were absent in the majority of the tumors induced by MNU. The loss of EGF receptor was not observed during the first 20 days post carcinogen treatment, but appeared to be correlated with the onset of the tumor. Consistent with the literature, the majority of the steroid receptor positive human breast cancer samples were EGF receptor negative, whereas steroid receptor negative samples contained EGF receptors. These results suggest that the loss of EGF receptors in ovarian hormone dependent mammary tumors does not occur gradually during carcinogenesis but appears to be a characteristic of hormone dependent mammary tumor cells.  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