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   124624篇
  免费   8242篇
  国内免费   454篇
耳鼻咽喉   1630篇
儿科学   3295篇
妇产科学   2070篇
基础医学   15964篇
口腔科学   2371篇
临床医学   12551篇
内科学   26354篇
皮肤病学   1915篇
神经病学   11970篇
特种医学   4271篇
外国民族医学   4篇
外科学   18017篇
综合类   1889篇
现状与发展   1篇
一般理论   168篇
预防医学   11112篇
眼科学   2913篇
药学   8720篇
  2篇
中国医学   173篇
肿瘤学   7930篇
  2023年   511篇
  2022年   831篇
  2021年   2073篇
  2020年   1227篇
  2019年   2014篇
  2018年   2319篇
  2017年   1786篇
  2016年   1957篇
  2015年   2412篇
  2014年   3439篇
  2013年   5336篇
  2012年   7763篇
  2011年   8288篇
  2010年   4689篇
  2009年   4512篇
  2008年   7967篇
  2007年   8520篇
  2006年   8350篇
  2005年   8642篇
  2004年   8175篇
  2003年   8001篇
  2002年   7574篇
  2001年   1180篇
  2000年   930篇
  1999年   1230篇
  1998年   1704篇
  1997年   1424篇
  1996年   1162篇
  1995年   1149篇
  1994年   942篇
  1993年   960篇
  1992年   754篇
  1991年   705篇
  1990年   670篇
  1989年   623篇
  1988年   576篇
  1987年   543篇
  1986年   544篇
  1985年   662篇
  1984年   832篇
  1983年   830篇
  1982年   1162篇
  1981年   1054篇
  1980年   950篇
  1979年   464篇
  1978年   575篇
  1977年   547篇
  1976年   449篇
  1975年   408篇
  1974年   365篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
101.
102.
103.
Monoclonal antibodies against human and bovine 2′:3′-cyclic nucleotide 3′-phosphodiesterase (CNPase) were generated by fusing FOX-NY myeloma cells with spleen cells from RBF/Dn mice previously immunized with the purified brain antigens. The enzyme isolated from bovine brain was quite basic, with an isoelectric point of 9.71 and both the bovine and human enzymes consisted of a closely spaced doublet at approximately 44 and 46 kDa on SDS-PAGE. Six monoclonals were identified as strongly recognizing the enzyme on both ELISA plates and on immunoblots of whole brain protein. Four monoclonals very weakly cross-reacted with guinea pig myelin basic protein. In contrast with two previous reports, some of our monoclonal antibodies did immunostain 2 or 3 protein bands in peripheral nerve, two bands closely corresponding to those immunostained in central nervous system (CNS) myelin, the Wolfgram protein fraction and in acetone powders of whole brain. Each of the 6 monoclonals reacting strongly on immunoblots recognized the enzyme in from 2 to 5 of the species examined (human, bovine, rat, mouse and rabbit). In addition, all 6 monoclonals that immunostained the enzyme in whole brain, myelin and Wolfgram protein immunoblots recognized both CNP1 (44 kDa) and CNP2 (46 kDa). The two closely spaced protein bands observed on SDS-PAGE and previously stained on immunoblots of CNS CNPase using polyvalent rabbit anti-bovine CNPase antisera, and now different monoclonal antibodies, appear to be immunologically related and to contain highly conserved sequences.  相似文献   
104.
105.
Vitamin E biokinetics, oxidative stress and cigarette smoking.   总被引:2,自引:0,他引:2  
Vitamin E is comprised of four tocopherols and four tocotrienols, and functions as a lipophilic chain-breaking antioxidant that prevents lipid peroxidation. Although it is well recognized that cigarette smoke is source of oxidative stress, relatively little is known regarding how oxidative stress alters vitamin E utilization in humans. Therefore, this review will highlight the recent knowledge regarding how cigarette smoking alters vitamin E (as alpha- and gamma-tocopherols) utilization in humans. Specifically, we will discuss the mechanisms by which cigarette smoking increases the turnover of plasma vitamin E, decreases the P450-mediated metabolism of vitamin E, and increases the nitration of gamma-tocopherol to result in the formation of 5-nitro-gamma-tocopherol. In addition, the interrelationship between oxidative stress and vitamin C will also be emphasized as it relates to vitamin E utilization.  相似文献   
106.
107.
Guidelines for design of clinical trials evaluating behavioral headache treatments were developed to facilitate production of quality research evaluating behavioral therapies for management of primary headache disorders. These guidelines were produced by a Workgroup of headache researchers under auspices of the American Headache Society. The guidelines are complementary to and modeled after guidelines for pharmacological trials published by the International Headache Society, but they address methodologic considerations unique to behavioral and other nonpharmacological treatments. Explicit guidelines for evaluating behavioral headache therapies are needed as the optimal methodology for behavioral (and other nonpharmacologic) trials necessarily differs from the preferred methodology for drug trials. In addition, trials comparing and integrating drug and behavioral therapies present methodological challenges not addressed by guidelines for pharmacologic research. These guidelines address patient selection, trial design for behavioral treatments and for comparisons across multiple treatment modalities (eg, behavioral vs pharmacologic), evaluation of results, and research ethics. Although developed specifically for behavioral therapies, the guidelines may apply to the design of clinical trials evaluating many forms of nonpharmacologic therapies for headache.  相似文献   
108.
Background There is a high rate of physical violence in populations with intellectual disabilities, and this has been linked to problems for the victim, the assailant, members of staff and services. Despite the clinical significance of this behaviour, few studies have assessed methods of predicting its occurrence. The present study examined clinical and actuarial methods of predicting violence in a forensic intellectual disability hospital. Methods The sample for the study consisted of people resident in the hospital during a 1‐year period (n = 124). Clinical prediction used a risk rating made by members of the person's clinical team, whereas actuarial prediction used the number of violent incidents in the 6‐months before the date of the clinical risk assessment. Computerized hospital records of violence in the 6 months after the assessment were used to examine the predictive accuracy of the two methods. Results The clinical method produced an area under the curve of 0.74 (95% CI: 0.65–0.83) in a receiver–operating characteristic curve analysis. The value for the actuarial method was 0.77 (95% CI: 0.69–0.86). Both methods performed at levels significantly above chance, but no one method was found to be superior to the other. Conclusions These findings suggest that it is possible to predict who is at risk of violence in forensic populations with intellectual disabilities. Here, the authors discuss the clinical implications of these findings and the clinical application of risk prediction within clinical services.  相似文献   
109.
The second part of this review addresses the treatment and prognosis of the vasculitides Wegener's granulomatosis, microscopic polyangiitis, Churg–Strauss syndrome and polyarteritis nodosa. Treatment regimens consist of an initial remission phase with aggressive immunosuppression, followed by a more prolonged maintenance phase using less toxic agents and doses. This review focuses on the initial treatment of fulminant vasculitis, the mainstay of which remains immunosuppression with steroids and cyclophosphamide. For Wegener's granulomatosis and microscopic polyangiitis plasma exchange can be considered for first-line therapy in patients with acute renal failure and/or pulmonary haemorrhage. Refractory disease is rare and is usually due to inadequate treatment. The vasculitides provide a particular challenge for the critical care team. Particular aspects of major organ support related to these conditions are discussed. Effective treatment has revolutionized the prognosis of these conditions. However, mortality is still approximately 50% for those requiring admission to intensive care unit. Furthermore, there is a high morbidity associated with both the diseases themselves and the treatment.  相似文献   
110.
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