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   3898288篇
  免费   324241篇
  国内免费   14672篇
耳鼻咽喉   56008篇
儿科学   126847篇
妇产科学   105595篇
基础医学   600940篇
口腔科学   108138篇
临床医学   345633篇
内科学   698283篇
皮肤病学   100014篇
神经病学   326196篇
特种医学   156690篇
外国民族医学   697篇
外科学   612156篇
综合类   114877篇
现状与发展   23篇
一般理论   2356篇
预防医学   320144篇
眼科学   91208篇
药学   274612篇
  18篇
中国医学   10533篇
肿瘤学   186233篇
  2021年   49699篇
  2020年   35403篇
  2019年   58521篇
  2018年   72706篇
  2017年   55162篇
  2016年   61023篇
  2015年   74777篇
  2014年   109189篇
  2013年   174667篇
  2012年   105190篇
  2011年   108128篇
  2010年   120972篇
  2009年   124216篇
  2008年   96127篇
  2007年   101706篇
  2006年   111600篇
  2005年   107432篇
  2004年   108634篇
  2003年   99376篇
  2002年   89535篇
  2001年   130672篇
  2000年   124241篇
  1999年   117990篇
  1998年   62429篇
  1997年   59295篇
  1996年   57194篇
  1995年   57911篇
  1994年   52268篇
  1993年   48546篇
  1992年   87144篇
  1991年   84131篇
  1990年   81090篇
  1989年   79404篇
  1988年   74250篇
  1987年   72551篇
  1986年   69414篇
  1985年   68514篇
  1984年   58897篇
  1983年   53072篇
  1982年   45016篇
  1981年   41882篇
  1980年   39480篇
  1979年   51002篇
  1978年   42258篇
  1977年   37848篇
  1976年   35170篇
  1975年   35348篇
  1974年   38237篇
  1973年   36826篇
  1972年   34856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