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   3469954篇
  免费   297419篇
  国内免费   15866篇
耳鼻咽喉   47610篇
儿科学   111703篇
妇产科学   92039篇
基础医学   550902篇
口腔科学   94769篇
临床医学   321461篇
内科学   606942篇
皮肤病学   91228篇
神经病学   298611篇
特种医学   135749篇
外国民族医学   392篇
外科学   528984篇
综合类   106245篇
现状与发展   23篇
一般理论   2326篇
预防医学   298251篇
眼科学   79371篇
药学   240892篇
  22篇
中国医学   10119篇
肿瘤学   165600篇
  2021年   50323篇
  2020年   35631篇
  2019年   58748篇
  2018年   72616篇
  2017年   55089篇
  2016年   60759篇
  2015年   74691篇
  2014年   109214篇
  2013年   175190篇
  2012年   102028篇
  2011年   103496篇
  2010年   120250篇
  2009年   123547篇
  2008年   88765篇
  2007年   92389篇
  2006年   102281篇
  2005年   97405篇
  2004年   98393篇
  2003年   88437篇
  2002年   77513篇
  2001年   106896篇
  2000年   99819篇
  1999年   97232篇
  1998年   60050篇
  1997年   57830篇
  1996年   55446篇
  1995年   56357篇
  1994年   50643篇
  1993年   47189篇
  1992年   70442篇
  1991年   67867篇
  1990年   64333篇
  1989年   62699篇
  1988年   58219篇
  1987年   56883篇
  1986年   54285篇
  1985年   54208篇
  1984年   49004篇
  1983年   44514篇
  1982年   41644篇
  1981年   39211篇
  1980年   36823篇
  1979年   40450篇
  1978年   35634篇
  1977年   32098篇
  1976年   29983篇
  1975年   28280篇
  1974年   29823篇
  1973年   28761篇
  1972年   26983篇
排序方式: 共有10000条查询结果,搜索用时 16 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