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   2427357篇
  免费   189024篇
  国内免费   8601篇
耳鼻咽喉   33640篇
儿科学   80729篇
妇产科学   67761篇
基础医学   344026篇
口腔科学   65393篇
临床医学   219511篇
内科学   477906篇
皮肤病学   54126篇
神经病学   194730篇
特种医学   94207篇
外国民族医学   1103篇
外科学   364468篇
综合类   61840篇
现状与发展   23篇
一般理论   784篇
预防医学   188653篇
眼科学   55343篇
药学   177602篇
  65篇
中国医学   8004篇
肿瘤学   135068篇
  2021年   19855篇
  2019年   20236篇
  2018年   28139篇
  2017年   21512篇
  2016年   23825篇
  2015年   27330篇
  2014年   38107篇
  2013年   55239篇
  2012年   76006篇
  2011年   80804篇
  2010年   47959篇
  2009年   45114篇
  2008年   74289篇
  2007年   78916篇
  2006年   79556篇
  2005年   77421篇
  2004年   73833篇
  2003年   70777篇
  2002年   68830篇
  2001年   117450篇
  2000年   121032篇
  1999年   102103篇
  1998年   29047篇
  1997年   26253篇
  1996年   26432篇
  1995年   25097篇
  1994年   23106篇
  1993年   21460篇
  1992年   78323篇
  1991年   75578篇
  1990年   72996篇
  1989年   69582篇
  1988年   64004篇
  1987年   62726篇
  1986年   58602篇
  1985年   56010篇
  1984年   42460篇
  1983年   35810篇
  1982年   21376篇
  1981年   19194篇
  1979年   37794篇
  1978年   26465篇
  1977年   22141篇
  1976年   20853篇
  1975年   22088篇
  1974年   26214篇
  1973年   25292篇
  1972年   23473篇
  1971年   21305篇
  1970年   20232篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Levels of the soluble form of the triggering receptor expressed on myeloid cells (sTREM)-1 are elevated in severe sepsis. However, it is not known whether sTREM-1 measurements can distinguish milder bacterial infections from noninfectious inflammation. The present authors studied whether serum sTREM-1 levels differ in community-acquired pneumonia, exacerbations of chronic obstructive pulmonary disease (COPD), asthma and controls, and whether sTREM-1 may be used as a surrogate marker for the need for antibiotics. Serum sTREM-1 levels in 150 patients with pneumonia, COPD and asthma exacerbations and 62 healthy controls were measured. Serum sTREM-1 levels were significantly elevated in pneumonia (median 295.2 ng x mL(-1)), COPD (280.3 ng x mL(-1)) and asthma exacerbations (184.0 ng x mL(-1)) compared with controls (83.1 ng x mL(-1)). Levels were higher in pneumonia and Anthonisen type 1 COPD exacerbations than in type 2 and 3 COPD and asthma exacerbations. The area under the receiver operating characteristics curve for sTREM-1 as a surrogate marker for the need for antibiotics was 0.77. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 were elevated predominantly in pneumonia and Anthonisen type 1 COPD exacerbations versus type 2 and 3 chronic obstructive pulmonary disease exacerbations, asthma and controls. Serum levels of the soluble form of the triggering receptor expressed on myeloid cells-1 has moderate but insufficient accuracy as a surrogate marker for the need for antibiotics in lower respiratory tract infections.  相似文献   
72.
Ninety-seven inpatients with tardive dyskinesia (average AIMS score = 13), the majority of whom were schizophrenic, were studied. Forty patients were Caucasian, and 57 were African-American. The APOE genotypes of these patients were compared to previously published genotypes of controls and with previously published studies of APOE genotypes in patients with schizophrenia. There were no significant differences in APOE allele frequencies comparing the African-American tardive dyskinesia population and the African-American control groups. In contrast, significant (< 0.05) P values were obtained comparing the Caucasian tardive dyskinesia population to the Caucasian controls, when comparing allele frequencies and genotypic frequencies. This study suggests that Caucasians bearing an APOE2 allele are at increased risk of developing tardive dyskinesia, whereas African-Americans are not. APOE genotype-specific risks of both tardive dyskinesia and Alzheimer's disease that vary across populations could be due to recruitment of patients or controls or could be due to modifying effects of differing genetic or environmental backgrounds. The mechanism by which the APOE2 allele increases risk of tardive dyskinesia is not known. Further information about the mechanisms of increased risk of tardive dyskinesia could result in stratification of prescribing practices weighing the costs of medications against the relative risk of side effects.  相似文献   
73.
74.
75.
Choledochojejunostomy (CJS) is commonly used for biliary reconstruction in liver transplantation for primary sclerosing cholangitis (PSC). We alternatively performed choledochoduodenostomy (CDS) and side-to-side choledochodocholedochstomy in a large cohort of patients. Fifty-one patients with PSC, transplanted between 1988 and 2000, were analyzed retrospectively. Biliary reconstruction was CDS in 25 (49%), CJS in 20 (39%) and CC in 6 transplantations (12%). Biliary leaks occurred in the early follow-up (< or =41 days) only in CDS patients (20%). However, in the late follow-up (>4 months), stricturing of anastomosis was found once in CDS (4%) and CJS (5%). Later (>9 months), intrahepatic bile duct strictures were diagnosed in four CDS (16%), one CJS (5%) and one CC (17%) patient(s). In 48% of CDS (12/25), 60% of CJS (12/20) and 17% of CC (1/6) at least one incidence of cholangitis was observed. Overall, biliary complication rates were significantly higher in CDS (40%) than CJS (10%) and CC (17%); of those none in CC and 12% in CDS were anastomosis-related. Graft/patient survival showed no significant differences among groups. Based on our results we consider CJS the standard method for biliary reconstruction in PSC; however, in selected cases where CJS is difficult to accomplish because of previous surgery or for retransplantation, CDS may present an alternative technique.  相似文献   
76.
77.
78.
79.
80.
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