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   27024篇
  免费   2206篇
  国内免费   38篇
耳鼻咽喉   418篇
儿科学   810篇
妇产科学   776篇
基础医学   3621篇
口腔科学   651篇
临床医学   3360篇
内科学   4617篇
皮肤病学   216篇
神经病学   2022篇
特种医学   927篇
外科学   3906篇
综合类   566篇
一般理论   19篇
预防医学   3170篇
眼科学   466篇
药学   1879篇
中国医学   47篇
肿瘤学   1797篇
  2021年   403篇
  2020年   242篇
  2019年   406篇
  2018年   461篇
  2017年   347篇
  2016年   339篇
  2015年   420篇
  2014年   544篇
  2013年   853篇
  2012年   1283篇
  2011年   1298篇
  2010年   726篇
  2009年   621篇
  2008年   1178篇
  2007年   1284篇
  2006年   1124篇
  2005年   1115篇
  2004年   1154篇
  2003年   1035篇
  2002年   1002篇
  2001年   890篇
  2000年   883篇
  1999年   731篇
  1998年   381篇
  1997年   351篇
  1996年   333篇
  1995年   319篇
  1994年   225篇
  1993年   204篇
  1992年   611篇
  1991年   528篇
  1990年   512篇
  1989年   498篇
  1988年   483篇
  1987年   433篇
  1986年   472篇
  1985年   466篇
  1984年   367篇
  1983年   308篇
  1982年   218篇
  1981年   202篇
  1980年   229篇
  1979年   357篇
  1978年   248篇
  1977年   229篇
  1975年   192篇
  1974年   230篇
  1973年   210篇
  1972年   207篇
  1969年   201篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
Using Syva EMIT reagents and a Cobas Bio centrifugal analyser we have developed a cost-effective assay for the detection of cannabinoids in urine. With this method, up to 1500 samples can be assayed with a single 100 test kit while maintaining acceptable precision. A mean CV of 6.1% was obtained for the concentration range 80-130 micrograms/l. The method is suitable for high-risk urines since heart treatment may be performed prior to analysis. There was no significant change in the measured concentration of cannabinoids in urine samples on storage in plastic containers, refrigerated or frozen, for up to seven weeks.  相似文献   
23.
24.
25.
Despite extensive investigation, the pathogenesis of the adult respiratory distress syndrome (ARDS) remains uncertain. As yet, there is no clear explanation of why some patients at risk for ARDS develop the syndrome, whereas others do not. Neutrophils and complement fragments have been implicated in the acute lung injury, but it is clear from published data that evidence of complement activation alone predicts neither the development nor the severity of ARDS. We investigated whether the combination of endotoxin, a leukocyte-priming agent, and complement fragments, leukocyte-stimulating agents, was associated with the development of ARDS. Ninety-eight patients were identified as being either at risk for the development of ARDS or having ARDS, and serial blood samples were obtained. There was no correlation between C5 fragments and the development of ARDS. C3 fragment levels were increased in 89% of the patients with ARDS, but they were also increased in 62% of patients at risk. Endotoxin was detected in 74% of the plasma samples obtained from patients at risk who subsequent developed ARDS and in 64% of the plasma samples obtained from the patients with ARDS. In contrast, only 22% of the plasma samples obtained from the patients at risk who did not develop ARDS had measurable endotoxin. We suggest that the combination of endotoxin and complement fragments may be one mechanism involved in the development of ARDS.  相似文献   
26.
27.
The immunologic risk associated with donor-specific antibodies (DSA) against Class II human leukocyte antigens (HLA) in kidney transplant (KTx) recipients is unclear. The aim of this study was to determine the outcome of KTx when DSA was detected only against HLA Class II. To isolate the impact of anti-Class II DSA, we retrospectively analyzed 12 KTx recipients who at baseline had a positive B-cell flow cytometric crossmatch (FXM) and a negative T-cell FXM. Using alloantibody specification analysis, 58.3% (7/12) had DSA against donor Class II and 41.7% had no demonstrable DSA. Biopsy-proven AMR occurred in 57% (4/7) in the Class II(+) group and 0% in the Class II(-) group (p > 0.05). Peritubular capillaries stained positive for C4d in 86% (6/7) of the Class II(+) patients and in 40% (2/5) of the Class II(-) patients (p > 0.05). One patient in the Class II(+) group lost their graft at 3 months to accelerated transplant glomerulopathy, while all other grafts were functioning 3-37 months posttransplant despite the persistence of anti-Class II DSA. We conclude that KTx recipients with clearly defined anti-Class II DSA are at risk for humoral rejection suggesting that desensitization and/or close posttransplant monitoring may be needed to prevent AMR.  相似文献   
28.
Fibromyalgia (FM) is a chronic, potentially disabling, cluster of symptoms that manifests as pain for 3 months or more and pain with pressure on 11 of 18 tender points throughout the body. Because there is no known cause, and therefore, no cure, treatment focuses on the control or relief of symptoms. Many patients are referred to rehabilitation settings for physical or exercise therapy. While exercise is helpful in the control of the pain, stiffness, fatigue, sleep disorders, and mood changes, a holistic approach to treatment is more effective. Rehabilitation nurses provide major support for patients with FM. Validation of the patients' experiences is essential for achieving quality of life. Many patients have a history of being undertreated because of a lack of credibility and invisibility of the illness. This article provides background information about FM, summarizes the FM trajectory, reviews approaches to management, and discusses the role of rehabilitation nurses in a holistic approach to care of clients with FM.  相似文献   
29.
30.
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