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   9028篇
  免费   517篇
  国内免费   28篇
耳鼻咽喉   127篇
儿科学   512篇
妇产科学   152篇
基础医学   991篇
口腔科学   228篇
临床医学   709篇
内科学   2050篇
皮肤病学   180篇
神经病学   577篇
特种医学   362篇
外国民族医学   1篇
外科学   1348篇
综合类   283篇
一般理论   8篇
预防医学   498篇
眼科学   201篇
药学   782篇
中国医学   38篇
肿瘤学   526篇
  2023年   65篇
  2022年   110篇
  2021年   298篇
  2020年   170篇
  2019年   206篇
  2018年   270篇
  2017年   199篇
  2016年   224篇
  2015年   248篇
  2014年   333篇
  2013年   454篇
  2012年   599篇
  2011年   644篇
  2010年   412篇
  2009年   308篇
  2008年   492篇
  2007年   510篇
  2006年   444篇
  2005年   397篇
  2004年   342篇
  2003年   291篇
  2002年   255篇
  2001年   194篇
  2000年   217篇
  1999年   182篇
  1998年   84篇
  1997年   51篇
  1996年   53篇
  1995年   50篇
  1994年   46篇
  1993年   33篇
  1992年   94篇
  1991年   94篇
  1990年   86篇
  1989年   108篇
  1988年   85篇
  1987年   69篇
  1986年   64篇
  1985年   71篇
  1984年   65篇
  1983年   64篇
  1982年   35篇
  1979年   47篇
  1978年   32篇
  1976年   32篇
  1975年   31篇
  1974年   38篇
  1973年   38篇
  1972年   31篇
  1969年   37篇
排序方式: 共有9573条查询结果,搜索用时 343 毫秒
11.
Molecular characterization of Wuchereria bancrofti is essential to develop suitable anti-filarial drugs and vaccines. We describe here isolation, sequence analysis and cloning of a partial cDNA of an enzyme superoxide dismutase from this parasite. The immunoscreening of a lambda zap W. bancrofti microfilarial (Mf) cDNA library with microfilaremic sera had resulted in the isolation of several seroreactive clones including, WbSOD. This clone contained a 309 bp insert and showed significant nucleotide and deduced amino acid sequence homologies to the superoxide dismutases of other nematode parasites. The antioxidant property of this enzyme may have important contribution in the defense mechanism of the parasite against host immune response.  相似文献   
12.
Brain tissues from 38 patients with a clinical suspicion of encephalitis or encephalopathy were examined by two immunoenzymatic techniques for the detection of arboviral antigen. Group B arboviral antigen was identified in 23 of these tissues. This simple method could be used for the diagnosis of the causal agent of encephalitis.  相似文献   
13.
The presence of accessory channels between the liver and extrahepatic bile ducts has long been recognised by anatomists and the division of such ducts may be a cause of bile leakage following cholecystectomy. However, visualisation of accessory bile ducts at operation is difficult as they are often small and sometimes less than 1 mm in diameter. Cholangiography has been used to help in the identification of accessory ducts in 50 patients included in a prospective trial. X-rays were taken after dissection of the gall bladder from its bed and extravasation of contrast was seen on five occasions (10%) suggesting leakage from divided accessory ducts. The identification of damage to accessory bile ducts in 10% of patients suggests that this may occur more frequently than previously supposed.  相似文献   
14.
We thank Coceani and L'Abbate for their comments on our paper.We concur that ‘pathophysiology cannot be inferred fromcoronary lumenography alone’, and this was one of thekey motivations in conducting the present study.  相似文献   
15.
16.
Congenital thoracic ectopic kidney is a very rare developmental anomaly and the rarest form of all ectopic kidneys. It is usually asymptomatic and discovered incidentally on routine chest radiography. Herein we reported the first case of staghorn stone in a thoracic kidney managed successfully by percutaneous nephrolithotomy.  相似文献   
17.
The rising incidence of hepatocellular carcinoma (HCC) in western countries, along with the poor prognosis offered by present-day treatment modalities, makes novel therapies for this disease necessary. Oncolytic herpes simplex viruses (HSV) are replication-competent viruses that are highly effective in the treatment of a wide variety of experimental models of human malignancies. This study seeks to investigate the effectiveness of oncolytic herpes viruses in the treatment of primary HCC cell lines. Sixteen commercially available human HCC cell lines were studied. G207 is an attenuated, replication-competent, oncolytic HSV engineered to selectively replicate within cancer cells. Cell lines were tested for viral sensitivity to G207 and their ability to support viral replication using standard cytotoxicity and viral replication assays. Eleven of 16 cell lines were moderately to highly sensitive to G207 viral oncolysis. HCC cell lines additionally demonstrated the ability to support viral replication in vitro with as high as 800-fold amplification of the administered viral dose observed. G207 is cytotoxic to, and efficiently replicates within, HCC cell lines in vitro. From these data, we suggest that oncolytic HSV therapy may have a role in the treatment of HCC, and in vivo studies are warranted. Presented in part at the 2005 American Hepato-Pancreato-Biliary Association Congress, Hollywood, Florida, April 14–17, 2005. Supported by grants R01CA75461 and R01CA72632 from the National Institutes of Health, and by grant MBC-99366 from the American Cancer Society (Yuman Fong).  相似文献   
18.
Growth retardation is seen in experimental animals as a result of severe dietary restriction of several essential trace elements. However, in humans, the effect of zinc deficiency is most pronounced. Growth failure and hypogonadism in males, related to a deficiency of zinc, have been recognized in many developing countries. A mild deficiency of zinc, affecting growth and development in children and adolescents, has been reported from developed countries as well. Zinc deficiency in humans may manifest as severe, moderate, or mild. The manifestations of severe zinc deficiency include bullous pustular dermatitis, alopecia, diarrhea, emotional disorder, weight loss, intercurrent infections due to cell-mediated immune dysfunctions, hypogonadism in males, neurosensory disorders, and problems with healing of ulcers. This condition can be fatal. A moderate level of zinc deficiency has been reported in a variety of conditions. Clinical manifestations include growth retardation and male hypogonadism in adolescence, rough skin, poor appetite, mental lethargy, delayed wound healing, cell-mediated immune dysfunctions, and abnormal neurosensory changes. A mild level of zinc deficiency may manifest with decreased serum testosterone level and oligospermia in males, decreased lean body mass, hyper-ammonemia, neurosensory changes, anergy, decreased serum thymulin activity, and decreased IL-2 activity. Although the clinical aspects of severe and moderate levels of zinc deficiency are well known, the recognition of mild levels of zinc deficiency has been difficult. Currently plasmas zinc appears to be the most widely used parameter for assessment of human zinc status, and it is known to be decreased in cases of severe and moderate deficiency of zinc.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
19.
20.
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