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   2344437篇
  免费   171752篇
  国内免费   5790篇
耳鼻咽喉   32175篇
儿科学   77570篇
妇产科学   66865篇
基础医学   343605篇
口腔科学   65374篇
临床医学   215723篇
内科学   451908篇
皮肤病学   47878篇
神经病学   189519篇
特种医学   87804篇
外国民族医学   696篇
外科学   342137篇
综合类   51071篇
现状与发展   2篇
一般理论   729篇
预防医学   188472篇
眼科学   53210篇
药学   175985篇
  7篇
中国医学   5044篇
肿瘤学   126205篇
  2018年   25208篇
  2017年   18973篇
  2016年   20978篇
  2015年   24036篇
  2014年   33178篇
  2013年   51217篇
  2012年   70243篇
  2011年   74947篇
  2010年   43943篇
  2009年   40837篇
  2008年   70247篇
  2007年   74990篇
  2006年   75785篇
  2005年   73752篇
  2004年   70570篇
  2003年   67717篇
  2002年   66178篇
  2001年   103815篇
  2000年   106501篇
  1999年   90069篇
  1998年   25961篇
  1997年   23422篇
  1996年   23362篇
  1995年   22106篇
  1994年   20838篇
  1993年   19436篇
  1992年   72426篇
  1991年   71348篇
  1990年   69690篇
  1989年   67039篇
  1988年   62266篇
  1987年   60816篇
  1986年   58137篇
  1985年   55618篇
  1984年   41779篇
  1983年   35929篇
  1982年   21685篇
  1981年   19228篇
  1979年   39017篇
  1978年   27645篇
  1977年   23316篇
  1976年   22465篇
  1975年   23854篇
  1974年   28556篇
  1973年   27843篇
  1972年   26144篇
  1971年   24262篇
  1970年   22595篇
  1969年   21276篇
  1968年   20100篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Short History of Interventional Neuroradiology What about the Future?   总被引:1,自引:0,他引:1  
1 Short historical background of interventional neuroradiology Even if a number of us were among the pioneers of Interventional Neuroradiology, this specialty has now reached its period of maturity. Schematically, the era of the pioneers began forty years ago and lasted about 15 years, between 1960 and 1975. During that period, on the initiative of Fedor Serbinenko (Russia) and Ren6 Djindjian (France), "intracerebral navigation " using small balloons, which became gradually "detachable", has been invented. At the same time, we discovered how to use these balloons to occlude intracranial vascular lesions, inaccessible or hardly accessible to traditional open skull neurosurgery, for example, carotid cavernous fistulas. Very rapidly, a lot of different embolic particles were successively tested, ranging at first from pieces of muscle, to small glass or silastic beads, gelfoam and dura mater pieces... During this period, parallel progress of hyperselective catheterization and consequently of microangiography allowed to establish new classifications of main vascular pathologies (distinction between brain arteriovenous malformations and dural fistulas ... ). These new classifications allowed a better understanding of physiopathology. This first period was thus primarily devoted to development of very precise diagnosis and techniques of hyperselective endovascular occlusion.  相似文献   
42.
43.
Bernard–Soulier syndrome (BSS) is a rare autosomal recessively inherited bleeding disorder. Pregnancy in patients with BSS is characterized by ante‐, intra‐, or postpartum haemorrhage, which may be delayed and severe. There is no consensus in the management of BSS in pregnancy and so far only 16 pregnancies in nine patients have been described. We report a further three pregnancies in two women with the syndrome. We also outline our management of pregnant patients with BSS.  相似文献   
44.
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes.  相似文献   
45.
46.
47.
48.
49.
50.
OBJECTIVE: A series of nasopharyngeal appliance designs is presented that represents our evolving experience over a 20-year period in the adjunctive use of prosthetic stents in the surgical correction of nasopharyngeal stenosis. DESIGN: Retrospective assessment of effectiveness of two nasopharyngeal stenosis hollow stent designs in a consecutive series of patients for relief of nasal obstructive symptoms. SETTING: Tertiary academic medical center, Craniofacial Program at Children's Hospital. PATIENTS: Four patients with nasopharyngeal stenosis were treated with a preoperatively fabricated stent made from a clasped palatal appliance onto which hollow acrylic conduits were extended through surgically re-created pharyngeal ports. A subsequent set of four patients with nasopharyngeal stenosis were treated with intraoperatively-fashioned silastic grommets, as opposed to palatal appliances. INTERVENTIONS: Postoperative intraoral stenting of nasopharyngeal ports. MAIN OUTCOME MEASURES: Maintenance of pharyngeal port opening after 1 year, improvement in nasal airway obstructive symptoms. RESULTS: The palatal appliance stents were less well tolerated and had a lower maintenance of port patency after device removal (4 of 8, 50%). The silastic grommets provided better retention into the ports and increased patient tolerance, as well as better 1-year port maintenance (6 of 8, 75%). CONCLUSIONS: The grommet stent appliance offers numerous advantages over a conventional dental-clasped appliance for prosthetic nasopharyngeal stenting, including obviation of extensive preoperative preparation, ease of insertion and removal, and exchange of air during the stenting period. Improved nasopharyngeal patency with this device may be due to greater patient tolerance and subsequent longer use.  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