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   3888019篇
  免费   322772篇
  国内免费   14146篇
耳鼻咽喉   54665篇
儿科学   125299篇
妇产科学   104660篇
基础医学   601742篇
口腔科学   107945篇
临床医学   352118篇
内科学   694946篇
皮肤病学   99878篇
神经病学   327241篇
特种医学   154853篇
外国民族医学   606篇
外科学   599954篇
综合类   114666篇
现状与发展   24篇
一般理论   2504篇
预防医学   325507篇
眼科学   90408篇
药学   271137篇
  21篇
中国医学   10179篇
肿瘤学   186584篇
  2021年   49582篇
  2020年   35240篇
  2019年   58208篇
  2018年   72412篇
  2017年   55032篇
  2016年   60699篇
  2015年   74342篇
  2014年   108502篇
  2013年   173729篇
  2012年   108055篇
  2011年   111392篇
  2010年   121073篇
  2009年   124144篇
  2008年   98615篇
  2007年   104160篇
  2006年   112929篇
  2005年   108940篇
  2004年   110061篇
  2003年   100273篇
  2002年   89859篇
  2001年   129855篇
  2000年   123407篇
  1999年   116702篇
  1998年   61753篇
  1997年   58960篇
  1996年   57095篇
  1995年   57717篇
  1994年   52117篇
  1993年   48528篇
  1992年   85923篇
  1991年   82767篇
  1990年   79366篇
  1989年   77593篇
  1988年   72160篇
  1987年   70623篇
  1986年   67634篇
  1985年   66320篇
  1984年   57659篇
  1983年   51942篇
  1982年   44625篇
  1981年   41699篇
  1980年   39343篇
  1979年   50141篇
  1978年   42140篇
  1977年   37458篇
  1976年   34655篇
  1975年   34473篇
  1974年   37665篇
  1973年   36527篇
  1972年   34523篇
排序方式: 共有10000条查询结果,搜索用时 46 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