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   3950772篇
  免费   330997篇
  国内免费   14734篇
耳鼻咽喉   55399篇
儿科学   127847篇
妇产科学   106663篇
基础医学   611106篇
口腔科学   107705篇
临床医学   353971篇
内科学   708920篇
皮肤病学   101506篇
神经病学   334460篇
特种医学   157108篇
外国民族医学   797篇
外科学   611864篇
综合类   119073篇
一般理论   2481篇
预防医学   327220篇
眼科学   92122篇
药学   275761篇
  17篇
中国医学   11023篇
肿瘤学   191460篇
  2021年   46828篇
  2020年   35406篇
  2019年   58325篇
  2018年   72354篇
  2017年   54847篇
  2016年   60541篇
  2015年   74409篇
  2014年   108762篇
  2013年   174249篇
  2012年   112176篇
  2011年   115563篇
  2010年   121910篇
  2009年   124986篇
  2008年   101975篇
  2007年   107870篇
  2006年   117153篇
  2005年   112749篇
  2004年   113721篇
  2003年   103969篇
  2002年   93237篇
  2001年   141907篇
  2000年   136113篇
  1999年   126148篇
  1998年   63571篇
  1997年   60390篇
  1996年   58144篇
  1995年   58892篇
  1994年   52934篇
  1993年   49235篇
  1992年   90897篇
  1991年   86435篇
  1990年   82331篇
  1989年   80181篇
  1988年   74154篇
  1987年   72709篇
  1986年   68942篇
  1985年   67882篇
  1984年   58643篇
  1983年   52585篇
  1982年   44954篇
  1981年   41807篇
  1980年   39368篇
  1979年   49527篇
  1978年   41380篇
  1977年   36809篇
  1976年   34145篇
  1975年   33427篇
  1974年   36223篇
  1973年   34993篇
  1972年   32929篇
排序方式: 共有10000条查询结果,搜索用时 31 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