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   3094209篇
  免费   271971篇
  国内免费   13546篇
耳鼻咽喉   43570篇
儿科学   99113篇
妇产科学   81345篇
基础医学   496888篇
口腔科学   83971篇
临床医学   273525篇
内科学   540120篇
皮肤病学   85612篇
神经病学   266908篇
特种医学   124927篇
外国民族医学   361篇
外科学   492771篇
综合类   96394篇
现状与发展   23篇
一般理论   2168篇
预防医学   256565篇
眼科学   70732篇
药学   212734篇
  17篇
中国医学   8801篇
肿瘤学   143181篇
  2021年   48844篇
  2020年   34850篇
  2019年   57797篇
  2018年   70190篇
  2017年   53193篇
  2016年   58752篇
  2015年   73061篇
  2014年   107094篇
  2013年   172139篇
  2012年   84009篇
  2011年   82975篇
  2010年   114145篇
  2009年   119465篇
  2008年   70877篇
  2007年   72867篇
  2006年   83939篇
  2005年   79931篇
  2004年   81852篇
  2003年   72890篇
  2002年   62813篇
  2001年   88514篇
  2000年   80697篇
  1999年   82522篇
  1998年   57614篇
  1997年   55944篇
  1996年   53568篇
  1995年   54349篇
  1994年   48661篇
  1993年   45444篇
  1992年   58133篇
  1991年   55129篇
  1990年   52230篇
  1989年   51596篇
  1988年   48075篇
  1987年   47065篇
  1986年   45105篇
  1985年   45324篇
  1984年   42778篇
  1983年   39494篇
  1982年   39383篇
  1981年   37140篇
  1980年   35086篇
  1979年   34732篇
  1978年   31817篇
  1977年   29259篇
  1976年   26902篇
  1975年   25475篇
  1974年   26046篇
  1973年   24942篇
  1972年   23562篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Many environmental risk factors for hepatobiliary cancers are known but whether they are associated with specific cancer types is unclear. We present here a novel approach of assessing standardized incidence ratios (SIRs) of previously diagnosed comorbidities for hepatocellular carcinoma (HCC), gallbladder cancer (GBC), cholangiocarcinoma (CCA) and ampullary cancer. The 13 comorbidities included alcohol and nonalcohol related liver disease, chronic obstructive pulmonary disease, gallstone disease, viral and other kinds of hepatitis, infection of bile ducts, hepatic and other autoimmune diseases, obesity and diabetes. Patients were identified from the Swedish Inpatient Register from 1987 to 2018, and their cancers were followed from 1997 onwards. SIRs for HCC were 80 to 100 in men and women diagnosed with hepatitis C virus and they were also >10 in patients diagnosed with hepatitis B virus, other kind of hepatitis, hepatic autoimmune disease and nonalcohol related liver disease. Many of these risks, as well as alcohol related liver disease, were either specific to HCC or were shared with intrahepatic CCA. For GBC, CCA and ampullary cancer infection of bile ducts was the main risk factor. Gallstone disease, nonhepatic autoimmune diseases and diabetes were associated with all hepatobiliary cancers. The limitations of the study include inability to cover some rare risk factors and limited follow-up time. Many of the considered comorbidities are characterized by chronic inflammation and/or overt immune disturbance in autoimmune diseases. The results suggest that local chronic inflammation and a related immune disturbance is the carcinogenic trigger for all these cancers.  相似文献   
2.
3.
4.
In the last decade, the development of new radiopharmaceuticals for the imaging and therapy of prostate cancer has been a highly active and important area of research, especially focusing on the prostate-specific membrane antigen (PSMA), an antigen which is upregulated in prostate, as well as in other tumor cells. A large variety of PSMA ligands have been radiolabeled, to date. Among the various derivatives, PSMA-617 resulted to be one of the most interesting in terms of interaction with the antigen and clinical properties, and its lutetium-177 labeled version has recently been approved by regulatory agencies for therapeutic purposes. For this reasons, the radiolabeling with fluorine-18 of a PSMA-617 derivative might be of interest. Beside other methodologies to radiolabel macromolecules with fluorine-18, the “click-chemistry” approach resulted to be very useful, and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) is considered one of most efficient and reliable. This paper proposes the synthesis of a suitable precursor for the radiolabeling with fluorine-18 of a new PSMA-617 derivative. The whole radiosynthetic procedure has been fully automated, and the final product, which proved to be stable in plasma, has been obtained with radiochemical yield and purity suitable for subsequent preclinical studies.  相似文献   
5.
6.
7.
8.
9.
10.
Aristodemou  E.  Retzepi  M.  Calciolari  E.  Donos  N. 《Clinical oral investigations》2022,26(8):5223-5235
Clinical Oral Investigations - To evaluate the effect of membrane occlusiveness and experimental diabetes on early and late healing following guided bone regeneration. A total of 30 Wistar rats...  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