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   28797篇
  免费   2166篇
  国内免费   85篇
耳鼻咽喉   431篇
儿科学   831篇
妇产科学   683篇
基础医学   3670篇
口腔科学   373篇
临床医学   2857篇
内科学   5902篇
皮肤病学   539篇
神经病学   2549篇
特种医学   1440篇
外科学   4637篇
综合类   302篇
一般理论   29篇
预防医学   2138篇
眼科学   653篇
药学   2059篇
中国医学   33篇
肿瘤学   1922篇
  2023年   307篇
  2022年   585篇
  2021年   1172篇
  2020年   657篇
  2019年   997篇
  2018年   1094篇
  2017年   746篇
  2016年   784篇
  2015年   988篇
  2014年   1261篇
  2013年   1585篇
  2012年   2274篇
  2011年   2323篇
  2010年   1235篇
  2009年   1003篇
  2008年   1575篇
  2007年   1592篇
  2006年   1488篇
  2005年   1339篇
  2004年   1163篇
  2003年   1018篇
  2002年   894篇
  2001年   365篇
  2000年   296篇
  1999年   280篇
  1998年   188篇
  1997年   146篇
  1996年   146篇
  1995年   115篇
  1994年   103篇
  1993年   87篇
  1992年   194篇
  1991年   182篇
  1990年   191篇
  1989年   189篇
  1988年   153篇
  1987年   183篇
  1986年   143篇
  1985年   180篇
  1984年   140篇
  1983年   118篇
  1982年   94篇
  1981年   104篇
  1980年   72篇
  1979年   105篇
  1978年   95篇
  1977年   81篇
  1975年   71篇
  1973年   91篇
  1972年   88篇
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
41.
42.
OBJECTIVE: Intra-abdominal packing is a valuable adjunct in patients with abdominal trauma and uncontrollable bleeding but few data exist regarding early and late outcome associated with this technique in patients with ruptured abdominal aortic aneurysm (AAA). METHODS: Interrogation of a prospective vascular surgical database identified 23 patients (22 men; median age 69, range 59-82, years) with ruptured AAA who required intra-abdominal packing for control of coagulopathic haemorrhage after insertion of an aortic graft between January 1982 and December 2003. Co-morbidity, operative and outcome data were retrieved. RESULTS: Haemostasis was achieved and packs were removed within 48 h in 20 patients. In those patients who had a graft inserted, the peri-operative mortality rate was 12 of 23 (52%) patients (vs. 172 of 455 (38%) patients who were not packed, NS). Three (13%) patients developed early intra-abdominal sepsis, which was universally fatal: graft-enteric fistula, intra-abdominal abscess with necrotizing fasciitis of the abdominal wound, and infected retroperitoneal haematoma. Two of 11 (18%) survivors developed late graft-related infective complications: major aortic graft infection at 6 months and symptomatic infected para-anastomotic aortic false aneurysm at 39 months. Early and late intra-abdominal infective complications were significantly more common in patients who were packed than in those who were not (packed: five of 23, 22% vs. non-packed: five of 455, 1%; p < 0.001). CONCLUSION: These data demonstrate that intra-abdominal packing in coagulopathic patients with ruptured AAA can achieve an acceptable survival rate. However, this technique may be associated with an increased incidence of early and late intra-abdominal infective complications.  相似文献   
43.
Anesthesia in 'stone man': myositis ossificans progressiva   总被引:1,自引:0,他引:1  
Myositis ossificans progressiva is a rare disease leading to complete ossification of the muscular system. Very little information about this rare disease and its anesthetic implications has appeared in anesthetic literature. This disease is felt to have an autosomal dominant pattern of inheritance and is usually associated with anomalies of the hands and feet. Afflicted patients are frequently misdiagnosed in childhood as having a rheumatologic disorder. Later in life (as true bone is formed in striated muscle, ligaments, and fascia), the correct diagnosis becomes obvious. Although muscles of the heart, diaphragm, larynx, and sphincters are spared, those of the chest wall are not, and pulmonary function progressively deteriorates. Death frequently occurs as a result of a pulmonary infection. Specific anesthetic considerations include positioning to avoid injury, potential need for fiberoptic intubation or tracheostomy, decreased thoracic compliance with the need for increased ventilating pressures, and the ultimate in disuse atrophy contraindicating the use of succinylcholine. Myositis ossificans progressiva can present the anesthesiologist with interesting challenges. Anesthetic management will need to be individualized according to the severity of the disease.  相似文献   
44.
We have generated transgenic mouse lineages that express the influenza virus hemagglutinin in different physical forms. One kind expresses the full-length hemagglutinin molecule as a cell surface glycoprotein and can be recognized by hemagglutinin-specific B and T cells. The other expresses a truncated polypeptide corresponding to the N-terminal third of the hemagglutinin molecule. This polypeptide encodes known hemagglutinin-specific T-cell determinants; however, it contains no native B-cell epitopes, since these depend on the conformation of the fully folded protein. In each case, the hemagglutinin transgenic mice display ubiquitous expression of transgenic messenger RNA and induce T-cell tolerance to the transgene-encoded T-cell determinant site 1. Thus, the hemagglutinin is a neo-self-antigen in both kinds of hemagglutinin transgenic mice and should provide a useful system for understanding the factors and mechanisms that govern tolerance and autoimmunity to self-antigens.  相似文献   
45.
46.
47.
48.
The therapeutic value of histamine H3-receptor ligands is under current investigation. On the basis of recently described diaryl imine prodrugs of the histamine H3-receptor agonist (R)-α-methyl-histamine ( 1 ) a series of new azomethine prodrugs containing five- and six-membered heterocycles were synthesized and tested for their in vitro hydrolysis rates and in vitro activity after oral application. It was found that electron-deficient six-membered heterocycles drastically destabilized the imine double bond so that these prodrugs decomposed unsuitably fast. On the contrary, prodrugs containing five-membered heterocycles appeared to be highly effective for the CNS delivery of 1 , and a remarkable correlation between chemical structure and pharmacokinetic profile was observed. Particularly (R)-4-fluoro-2-[[N-[1-(1H-imidazol-4-yl)-2-propyl]imino](1H-pyrrol-2-yl)methyl]phenol ( 8c ), the 2-furanyl analogue 8d , and its 3-furanyl isomer 8e proved to be equipotent to the most potent of recently described halogenated diaryl imine prodrugs of 1. However, in contrast to any other azomethine prodrug, 8c exhibited an incomparably long lasting delivery of 1 in the CNS and can thus be regarded as a ‘retard’ prodrug. Assuming that a therapeutic indication of histamine H3-receptor agonists will soon be established, these highly potent heteroarylphenyl azomethine prodrugs, which already serve as valuable pharmacological tools, may also become potential drugs in clinical use.  相似文献   
49.
50.
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