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   4303篇
  免费   212篇
  国内免费   23篇
耳鼻咽喉   17篇
儿科学   102篇
妇产科学   32篇
基础医学   546篇
口腔科学   148篇
临床医学   356篇
内科学   1276篇
皮肤病学   67篇
神经病学   279篇
特种医学   257篇
外科学   526篇
综合类   26篇
预防医学   187篇
眼科学   29篇
药学   328篇
中国医学   7篇
肿瘤学   355篇
  2023年   24篇
  2022年   43篇
  2021年   86篇
  2020年   47篇
  2019年   66篇
  2018年   81篇
  2017年   69篇
  2016年   61篇
  2015年   79篇
  2014年   86篇
  2013年   113篇
  2012年   199篇
  2011年   197篇
  2010年   147篇
  2009年   124篇
  2008年   191篇
  2007年   201篇
  2006年   173篇
  2005年   182篇
  2004年   187篇
  2003年   190篇
  2002年   167篇
  2001年   142篇
  2000年   148篇
  1999年   133篇
  1998年   89篇
  1997年   88篇
  1996年   76篇
  1995年   63篇
  1994年   50篇
  1993年   40篇
  1992年   96篇
  1991年   81篇
  1990年   85篇
  1989年   88篇
  1988年   73篇
  1987年   49篇
  1986年   82篇
  1985年   58篇
  1984年   43篇
  1983年   50篇
  1982年   30篇
  1981年   20篇
  1980年   23篇
  1979年   43篇
  1978年   37篇
  1977年   21篇
  1976年   15篇
  1975年   15篇
  1973年   19篇
排序方式: 共有4538条查询结果,搜索用时 15 毫秒
61.
62.
63.
The radiologic features of ureteral and bladder hernias are poorly known. These hernias can be located in 5 compartments, being extremely rare in 2 of them--the chest and lumbar sectors, where only 2 cases are reported in literature. In the other 3 compartments--i.e., ischiatic, crural and inguinal sectors--bladder and ureteral hernias are less uncommon findings. Over a relatively short period of time, 5 bladder hernias were observed--3 ischiatic, 1 inguino-scrotal and 1 crural cases--and 1 double ureteral hernia, which was inguinal on the right-hand side and ischiatic on the left-hand side. Thus, we reviewed the main urographic and cystographic signs on the basis of a previous report by one of us. In discussing the new cases, we emphasize the importance of a few typical diagnostic signs, which follow: asymmetry and anomalous location of herniated organs, ureter protrusion beyond the pelvic bones outline, the presence of ureteral spiral ("curlicue sign"), and bladder walls indentation.  相似文献   
64.
B Salvadori  M Greco  A R Conti 《Tumori》1979,65(3):279-288
The surgical approach to minimal breast cancer is still under discussion. In fact by the term "minimal" three lesions are meant, namely "lobular carcinoma in situ", "intraductal carcinoma" and invasive "microcarcinoma". It is really difficult to indicate appropriate treatment for these tumors, also because the series reported in the literature are few and represented by a small number of cases. The present paper is a critical review of the literature on the subject. According to the most recent view lobular carcinoma in situ and intraductal carcinoma demand for radical surgery (total mastectomy) due to the high percentage of multicentricity and bilaterality of these lesions. More particularly with regard to lobular carcinoma in situ recent reports claim for a "wait and see" policy which is gaining favour, on the ground that the risk of developing invasive cancer in women with lobular carcinoma in situ is not so high and that the period of time between diagnosis of the lobular carcinoma and the development of the invasive cancer is usually very long. On the other side, for intraductal carcinoma, axillary dissection seems to be pleonastic due to the low percentage of secondary deposits in axillary lymph-nodes (1-3%) in women operated on for intraductal carcinoma. Invasive microcardinomas, less than 5 mm in diameter, should be considered as T1N0 tumors; actually there is no reason to treat them by a more conservative surgery than is done for T1N0 cancers, as they present the same involvement of the axillary lymph nodes. In a small series of 38 microcarcinoma observed at the Milan Cancer Institut N+ cases were 27%.  相似文献   
65.
66.
67.
68.
NIV indications and application in critically ill patients have considerably expanded in the last few years: the aim of this paper is to shortly review NIV main indications, on the basis of data from the current scientific literature.  相似文献   
69.
Gas conditioning in artificial respiration   总被引:1,自引:0,他引:1  
The authors review the main systems used in the clinical setting to condition inspiratory gases during mechanical ventilation. More in details, the functional principles of hot water humidifiers and heat and moisture exchangers are described.  相似文献   
70.
PURPOSE: The purpose of this study was to determine the role of functional interactions between pancreatic cancer cells and pancreatic stellate cells (PSCs) in the formation of the desmoplastic reaction (DR) in pancreatic cancer and to characterize the effect of type I collagen (the predominant component of the DR) on pancreatic cancer cell phenotype. EXPERIMENTAL DESIGN: PSCs and type I collagen were identified in sections of pancreatic cancer using immunohistochemistry, and their anatomic relationship was studied. Interactions among pancreatic cancer cell lines (MIA PaCa-2, Panc-1, and AsPC-1), primary cultures of human PSCs, and type I collagen were investigated in a series of tissue culture models. RESULTS: In vivo, the DR causes gross distortion of normal pancreas, bringing cancer cells into close contact with numerous PSCs and abundant type I collagen. In tissue culture models of pancreatic cancer, conditioned media from each cell line increased PSC [3H]thymidine incorporation up to 6.3-fold that of controls, and AsPC-1 cells also increased PSC collagen synthesis 1.3-fold. Type I collagen was observed to increase long-term survival of pancreatic cancer cells treated with 5-fluorouracil, by up to 62% in clonogenic assays. This was because type I collagen increased the proliferation of cancer cells ([3H]thymidine incorporation was up to 2.8-fold that of cells cultured on tissue culture plastic) and reduced apoptosis of AsPC-1 cells in response to 5-fluorouracil (by regulating mcl-1). CONCLUSIONS: These experiments elucidate a mechanism by which the DR in pancreatic cancer may form and, via the collagen within it, promote the malignant phenotype of pancreatic cancer cells, suggesting significant detriment to the host.  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