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   5452篇
  免费   553篇
  国内免费   133篇
耳鼻咽喉   42篇
儿科学   132篇
妇产科学   247篇
基础医学   705篇
口腔科学   67篇
临床医学   600篇
内科学   1083篇
皮肤病学   92篇
神经病学   431篇
特种医学   346篇
外科学   728篇
综合类   126篇
预防医学   328篇
眼科学   102篇
药学   430篇
中国医学   27篇
肿瘤学   652篇
  2023年   32篇
  2022年   53篇
  2021年   126篇
  2020年   99篇
  2019年   181篇
  2018年   183篇
  2017年   124篇
  2016年   141篇
  2015年   186篇
  2014年   217篇
  2013年   328篇
  2012年   371篇
  2011年   375篇
  2010年   263篇
  2009年   207篇
  2008年   283篇
  2007年   323篇
  2006年   258篇
  2005年   276篇
  2004年   248篇
  2003年   217篇
  2002年   208篇
  2001年   176篇
  2000年   152篇
  1999年   152篇
  1998年   58篇
  1997年   48篇
  1996年   39篇
  1995年   34篇
  1994年   28篇
  1993年   35篇
  1992年   86篇
  1991年   83篇
  1990年   55篇
  1989年   56篇
  1988年   57篇
  1987年   51篇
  1986年   45篇
  1985年   48篇
  1984年   41篇
  1983年   23篇
  1982年   21篇
  1981年   13篇
  1980年   13篇
  1979年   12篇
  1978年   16篇
  1977年   12篇
  1975年   12篇
  1974年   11篇
  1969年   9篇
排序方式: 共有6138条查询结果,搜索用时 31 毫秒
101.
In March 2018, an abortion storm caused by porcine reproductive and respiratory syndrome virus was confirmed in a farrow‐to‐finish pig herd in Taiwan. Open reading frame 5 and non‐structural protein 2 of the virus confirmed that the virus is closely related to the virulent strains circulating in the United States.  相似文献   
102.
103.
104.
105.
106.
107.
108.
Background: Spontaneous bacterial empyema (SBE) is a complication of cirrhotic patients in which a pre‐existing pleural effusion becomes infected. This retrospective study was designed to investigate the bacteriology and outcome predictors of SBE in cirrhotic patients. Methods: Medical records of cirrhotic patients treated in a tertiary care university hospital from December 2004 to December 2008 were retrospectively reviewed. Results: Of 3390 cirrhotic patients seen during the study period, 81 cases of SBE were diagnosed. The incidence of SBE was 2.4% (81/3390) in cirrhotic patients and 16% (81/508) in patients with cirrhosis with hydrothorax. There were 46 monomicrobial infections found in 46 SBE patients. Aerobic Gram‐negative organisms were the predominant pathogens (n=29, 63%), and Escherichia coli (n=9, 20%) was the most frequently isolated sole pathogen. The mortality rate of SBE was 38% (31/81). Univariate analysis showed that Child–Pugh score, model for end‐stage liver disease (MELD)–Na score, concomitant bacteraemia, concomitant spontaneous bacterial peritonitis, initial intensive care unit (ICU) admission and initial antibiotic treatment failure were predictors of poor outcomes. Multivariate regression analysis demonstrated that the independent factors related to a poor outcome were initial ICU admission [odds ratio (OR): 4.318; 95% confidence interval 1CI) 1.09–17.03; P=0.037], MELD–Na score (OR: 1.267; 95% CI 1.08–1.49; P=0.004) and initial antibiotic treatment failure (OR: 13.10; 95% CI 2.60–66.03). Conclusion: Spontaneous bacterial empyema in cirrhotic patients is a high mortality complication. The independent factors related to poor outcome are high MELD–Na score, initial ICU admission and initial antibiotic treatment failure. High MELD–Na score may be a useful mortality predictor of SBE in cirrhotic patients.  相似文献   
109.
The acinus-mimicking microfluidic chip, which simulates the in vivo condition of the liver, was developed and reported in this paper. The gradient microenvironment of the liver acinus is replicated within this proposed microfluidic chip. The advantage of this acinus-mimicking chip is capable of adjusting the concentration gradient in a relatively short period of time at around 10 s. At the same instance the non-linear concentration gradient can be presented in the various zones within this microfluidic chip. The other advantage of this proposed design is in the convenience of allowing the direct injection of the cells into the chip. The environment within the chip is multi-welled and gel-free with high cell density. The multi-row pillar microstructure located at the entrance of the top and bottom flow channels is designed to be able to balance the pressure of the perfusion medium. Through this mechanism the shear stress experienced by the cultured cells can be minimized to reduce the potential damage flow from the perfusion process. (3)The fluorescence staining and the observations of the cell morphology verify the life and death of the cells. The shear stress experienced by the cells in the various zones within the chip can be effectively mapped. The serum glutamic oxaloacetic transaminase (SGOT) collected from the supernatants was used to determine the effects of the degassing process and the shear stress of the medium flow on the cultured cells.  相似文献   
110.
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