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   164943篇
  免费   6820篇
  国内免费   369篇
耳鼻咽喉   2198篇
儿科学   4884篇
妇产科学   3831篇
基础医学   23703篇
口腔科学   5431篇
临床医学   9438篇
内科学   36492篇
皮肤病学   4478篇
神经病学   13185篇
特种医学   4471篇
外国民族医学   1篇
外科学   19001篇
综合类   796篇
一般理论   24篇
预防医学   19715篇
眼科学   4339篇
药学   12840篇
中国医学   662篇
肿瘤学   6643篇
  2023年   820篇
  2021年   2436篇
  2020年   1378篇
  2019年   2817篇
  2018年   4978篇
  2017年   3090篇
  2016年   3094篇
  2015年   3442篇
  2014年   3753篇
  2013年   5791篇
  2012年   10066篇
  2011年   10618篇
  2010年   5275篇
  2009年   3827篇
  2008年   8711篇
  2007年   9371篇
  2006年   8989篇
  2005年   8596篇
  2004年   7969篇
  2003年   7472篇
  2002年   7121篇
  2001年   4891篇
  2000年   5490篇
  1999年   4177篇
  1998年   845篇
  1996年   575篇
  1992年   2244篇
  1991年   2011篇
  1990年   1991篇
  1989年   1741篇
  1988年   1650篇
  1987年   1558篇
  1986年   1590篇
  1985年   1501篇
  1984年   1066篇
  1983年   929篇
  1979年   1219篇
  1978年   821篇
  1977年   801篇
  1976年   765篇
  1975年   900篇
  1974年   1120篇
  1973年   1165篇
  1972年   1110篇
  1971年   1082篇
  1970年   1007篇
  1969年   1082篇
  1968年   1105篇
  1967年   977篇
  1966年   880篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Gallibacterium anatis (previously named Pasteurella haemolytica-like) is considered a normal inhabitant of genital and upper respiratory tracts of healthy chickens, but it is also associated with different pathological conditions. Secreted metalloproteases from field and reference G. anatis cultures were obtained by methanol precipitation and were characterized. Proteins of molecular mass higher than 100 kDa showing proteolytic activity were observed in 10% polyacrylamide gels copolymerized with 1% bovine casein. They were active at alkaline pH, and inhibited by ethylenediamine tetraacetic acid. Their activity was stable at 50 degrees C, but partially inhibited at 60 degrees C, and totally inhibited at higher temperatures. Secreted proteins were able to degrade chicken IgG after 24 h of incubation, and cross-reacted with a polyclonal antibody against purified protease from Actinobacillus pleuropneumoniae. Secreted metalloproteases could play a role in infections caused by G. anatis.  相似文献   
132.
BACKGROUND: In an attempt to raise the survival of an unselected and representative population of oral and oropharyngeal squamous cell cancer patients, a pilot study of an integrated four-modality treatment was conceived. Final endpoints were compliance, loco-regional control, survival (after complete 5-year follow-up), and a concept of trial assessment using the treatment-dependent prognostic index TPI. PATIENTS: Eighty-seven consecutive patients with histologically proven untreated stages I-IV disease presented in the period between 1997 and 1999 of whom 14 had to be considered uncurable and 73 were fit to be treated with the intention of achieving a cure. METHODS: All patients received one cycle of neoadjuvant intraarterial chemotherapy with 150 mg/m(2) cisplatin (systemically neutralized with sodium thiosulphate), and, if possible, by consecutive treatment applying both surgery of the primary tumour and the neck lymphatics, as well as by adjuvant radiation over 5 weeks (51.3 Gy) plus concurrent chemotherapy (weekly systemic docetaxel 25 mg/m(2)). RESULTS: Ninety per cent of all cases and 96% of the patients treated with curative intention received more than one modality due to study design. Patient non-compliance in the group treated with curative intention has been 18/73 (=25%), and protocol compliance has been 32/73 (=44%). The locoregional control rate for all cases was 71% (62/87 patients) and for the patients treated with curative intention 83.5% (61/73 patients). Thirteen/fourteen non-curable patients died after a mean period of 4 months. After a median observation time of 5 years, the final absolute survival of the unselected population was 53%, and of the patients treated with curative intention 62% (especially, 70% and 50% for patients with operable stages III and IV, respectively). CONCLUSION: The multimodality regimen as presented proved feasible and showed high objective and relative survival rates in comparison with known data from tumour registries of unselected populations. Intra-arterial chemotherapy should be considered a valuable addition to treatment. The potential of survival benefit from this multimodality regimen in comparison with the prognosis index TPI should be investigated in further studies.  相似文献   
133.
134.

Introduction  

This paper presents the results of a study on the psychometric properties of an authorized Spanish version of the McMaster Family Assessment Device, a self-report measure of family functioning.  相似文献   
135.
136.
137.
138.
139.
140.
To obtain a new model of chronic portal hypertension in the rat, two classical methods to produce portal hypertension, partial portal vein ligation and the oral administration of thioacetamide (TAA), have been combined. Male Wistar rats were divided into four groups: 1 (control; n?=?10), 2 [triple partial portal vein ligation (TPVL); n?=?9], 3 (TAA; n?=?11), and 4 (TPVL plus TAA; n?=?9). After 3 months, portal pressure, types of portosystemic collateral circulation, laboratory hepatic function tests (aspartate aminotransferase, alanine aminotransferase, bilirubin, alkaline phosphatase, and gamma-glutamyl transpeptidase) and liver histology were studied. The animals belonging to group 2 (TPVL) developed extrahepatic portosystemic collateral circulation, associated with mesenteric venous vasculopathy without hepatic destructurization or portal hypertension. Animals from group 3 (TAA) developed cirrhosis and portal hypertension but not extrahepatic portosystemic collateral circulation, or mesenteric venous vasculopathy. Finally, the animals from group 4 (TPVL?+?TAA) developed cirrhosis, portal hypertension, portosystemic collateral circulation, and mesenteric venous vasculopathy. The association of TPVL and TAA can be used to obtain a model of chronic portal hypertension in the rat that includes all the alterations that patients with hepatic cirrhosis usually have. This could, therefore, prove to be a useful tool to study the pathophysiological mechanisms involved in these alterations.  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