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   6712篇
  免费   604篇
  国内免费   165篇
耳鼻咽喉   61篇
儿科学   149篇
妇产科学   180篇
基础医学   940篇
口腔科学   263篇
临床医学   847篇
内科学   1278篇
皮肤病学   59篇
神经病学   568篇
特种医学   216篇
外科学   937篇
综合类   123篇
一般理论   9篇
预防医学   832篇
眼科学   43篇
药学   504篇
中国医学   8篇
肿瘤学   464篇
  2022年   40篇
  2021年   141篇
  2020年   95篇
  2019年   146篇
  2018年   143篇
  2017年   102篇
  2016年   129篇
  2015年   140篇
  2014年   186篇
  2013年   229篇
  2012年   387篇
  2011年   396篇
  2010年   193篇
  2009年   184篇
  2008年   318篇
  2007年   348篇
  2006年   355篇
  2005年   316篇
  2004年   318篇
  2003年   263篇
  2002年   278篇
  2001年   226篇
  2000年   232篇
  1999年   158篇
  1998年   94篇
  1997年   76篇
  1996年   50篇
  1995年   71篇
  1994年   62篇
  1993年   54篇
  1992年   112篇
  1991年   126篇
  1990年   106篇
  1989年   87篇
  1988年   62篇
  1987年   88篇
  1986年   99篇
  1985年   91篇
  1984年   70篇
  1983年   69篇
  1982年   43篇
  1981年   39篇
  1979年   65篇
  1978年   46篇
  1977年   47篇
  1975年   43篇
  1974年   49篇
  1973年   35篇
  1972年   45篇
  1969年   42篇
排序方式: 共有7481条查询结果,搜索用时 111 毫秒
1.
Graefe's Archive for Clinical and Experimental Ophthalmology - To evaluate the long-term safety and efficacy of intrastromal bevacizumab for treatment of deep corneal neovascularization in...  相似文献   
2.
3.
We have presented a rare case of primary involvement of the anterior mediastinum by osteogenic sarcoma in which CT was useful in demonstrating calcium within the mass, and in distinguishing the mass from surrounding bony structures. Although rare, extraosseous osteogenic sarcoma should be included in the differential diagnosis of a calcified anterior mediastinal mass.  相似文献   
4.
5.
6.
Contemporary discourse contains numerous examples of use of the concept of culture by social and behavioral scientists. Simple reification, where the speaker makes culture into a thing capable of action exemplifies one usage in public discourse. Some quantitative social scientists attempt to characterize people’s cultural identities by means of a single categorical variable, which often “lumps” people into categories such as “Hispanic” or “Black” that in fact have numerous culturally bounded subcategories. Approaches that emphasize cultural process are preferable to those who attempt to categorize; more complex measures of acculturation help investigators to make convincing analyses of circumstances in which health disparities occur. Examples in which investigators make appropriate use of cultural characterizations demonstrate their utility in investigating health disparities in Haitian American women, injecting and noninjecting drug users, Hispanic youth, and adult Hispanics at risk of HIV infection. Focus on culture in the study of health disparities can identify entanglements between structural factors such as poverty and lack of education and cultural factors such as beliefs about health. Qualitative methods coupled with quantitative methods have great potential to improve investigators’ grasp of cultural nuance while capturing the distribution of qualitatively derived behaviors.  相似文献   
7.
Originally described by Rosen in 1983, syringomatous nipple adenoma (SAN) is a tumor of disputed histogenesis, which can be problematic both diagnostically and therapeutically. 1 It is a benign primary tumor of breast epithelium with histology similar to that of the syringoma. In the current case, we describe a 40-year-old female with this lesion occurring within a supernumerary breast. This case represents, to our knowledge, the first such reported case, and represents a significant finding as its presence could lend some confusion as to whether or not this represents a benign primary process of breast or a potentially infiltrative tumor of the skin.  相似文献   
8.
9.
10.
Proteoglycans have been isolated and analysed from extracts of normal and chronically inflamed human gingiva in order to determine the effects of chronic inflammation on these important soft connective tissue extracellular macromolecules. The uronic acid content of glycosaminoglycans isolated by papain digestion of normal and inflamed gingiva did not differ significantly. Likewise, electrophoretic analysis revealed that the content of hyaluronic acid, heparan sulfate, dermatan sulfate and chondroitin sulfute was similar. The sulfated glycosaminoglycans from both sources eluted from a Sepharose C1-6B column with a Kav of 0.45 (approximate Mr 25,000). However, hyaluronic acid from normal gingiva was predominantly of a large size eluting in the void volume of a Sepharose. CL-6B column, while that isolated from inflamed tissue was mostly a small molecular weight species which elutccl in the included volume of a Sepharose CL-6B column. Using dissociative conditions, intact proteoglycans could be more readily extracted from inflamed tissues (90% of the total tissue uronic acid) than from normal tissues where only 80% of the total tissue uronic acid was extractable. Even though DEAE-Sephacel ion-exchange chromatography revealed no differences in charge between normal and inflamed gingival proteoglycans, Sepharose CL-4B chromatography revealed more molecular size polydispersity in samples from inflamed tissue than from normal tissue. Taken together, these results indicate that while hyaluronic acid is depolymerized in inflamed tissue, no evidence of sulfated glycosaminoglycan degradation was found. Therefore, the most likely cause for disruption to the molecular integrity of the proteoglycans is via proteolytic alteration to the proteoglycan core protein.  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