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   32469篇
  免费   3100篇
  国内免费   42篇
耳鼻咽喉   287篇
儿科学   997篇
妇产科学   799篇
基础医学   4656篇
口腔科学   719篇
临床医学   3824篇
内科学   6665篇
皮肤病学   493篇
神经病学   3455篇
特种医学   862篇
外科学   3827篇
综合类   641篇
一般理论   29篇
预防医学   3571篇
眼科学   511篇
药学   2549篇
  1篇
中国医学   44篇
肿瘤学   1681篇
  2022年   237篇
  2021年   583篇
  2020年   325篇
  2019年   578篇
  2018年   627篇
  2017年   485篇
  2016年   500篇
  2015年   573篇
  2014年   789篇
  2013年   1194篇
  2012年   1739篇
  2011年   1759篇
  2010年   988篇
  2009年   820篇
  2008年   1463篇
  2007年   1720篇
  2006年   1593篇
  2005年   1615篇
  2004年   1451篇
  2003年   1503篇
  2002年   1340篇
  2001年   764篇
  2000年   728篇
  1999年   645篇
  1998年   382篇
  1997年   305篇
  1996年   298篇
  1995年   308篇
  1994年   280篇
  1993年   265篇
  1992年   561篇
  1991年   510篇
  1990年   498篇
  1989年   488篇
  1988年   446篇
  1987年   447篇
  1986年   393篇
  1985年   459篇
  1984年   411篇
  1983年   315篇
  1982年   326篇
  1981年   280篇
  1980年   262篇
  1979年   361篇
  1978年   317篇
  1977年   226篇
  1976年   258篇
  1974年   283篇
  1973年   295篇
  1972年   238篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Research on physical activity (PA) by level of acculturation in Hispanic children is limited and findings have been mixed. We examined PA participation by primary language used with parents in a representative sample of 4th, 8th, and 11th grade Texas public school students. Mixed-effects regression models were conducted using cross-sectional data from the 2004–2005 School Physical Activity and Nutrition Study (n = 22,049). Self-reported PA was compared among three language-ethnic groups: Spanish-Hispanic (SH) (referent); English-Hispanic (EH); and English-Other (EO). EH and/or EO girls were generally between 1.25 and 2.58 [OR] times more likely to participate in PA across grade levels, with the largest differences found for school sports in 8th grade girls. EH and EO 8th grade boys were 1.71 (CI: 1.40, 2.10) and 2.06 (CI: 1.68, 2.51) times, respectively, more likely to participate in school sports. Findings indicate important disparities in Spanish-speaking Hispanic children’s PA participation.  相似文献   
22.
Hypoxia is related to poor prognosis because it is associated to chemo-and radioresistance. During recent years the evolution of imaging methods like PET/CT and MRI has meant the appearance of new perspectives with direct implications in radiation therapy. We discuss previous experiences in staging, planning and in the follow-up process with these techniques for measuring tumour hypoxia.  相似文献   
23.
Popliteal artery aneurysms representing 80% of peripheral artery aneurysms rarely rupture (a reported incidence of 0.1–2.8 %) and second commonest in frequency after aorto-iliac aneurysms. They usually present with pain, swelling, occlusion or distal embolisation and can cause diagnostic difficulties. We report a 78 year old man who was previously admitted to hospital with a pulmonary embolus secondary to deep venous thrombosis. He was heparinized then warfarinised and was readmitted with a ruptured popliteal aneurysm leading to a large pseudo aneurysm formation. The pulmonary embolus had been due to popliteal vein thrombosis and propagation of the clot. A thorough review of literature identified only one previously reported case of ruptured popliteal artery aneurysm and subsequent large pseudo aneurysm formation. We feel it is important to exclude a popliteal aneurysm in a patient with DVT. This may be more common than the published literature suggests.  相似文献   
24.
OBJECTIVE: To identify the possible contribution of electromyogram (EMG) to scalp electroencephalogram (EEG) rhythms at rest and induced or evoked by cognitive tasks. METHODS: Scalp EEG recordings were made on two subjects in presence and absence of complete neuromuscular blockade, sparing the dominant arm. The subjects undertook cognitive tasks in both states to allow direct comparison of electrical recordings. RESULTS: EEG rhythms in the paralysed state differed significantly compared with the unparalysed state, with 10- to 200-fold differences in the power of frequencies above 20 Hz during paralysis. CONCLUSIONS: Most of the scalp EEG recording above 20 Hz is of EMG origin. Previous studies measuring gamma EEG need to be re-evaluated. SIGNIFICANCE: This has a significant impact on measurements of gamma rhythms from the scalp EEG in unparalysed humans. It is to be hoped that signal separation methods will be able to rectify this situation.  相似文献   
25.
26.
A technique for arthrodesis of small joints of the hand is described that uses a tenon to secure apposition that has good intrinsic stability as well as a large surface area of cancellous bony contact. A minimum of postoperative immobilization is required. The tenon arthrodesis method has been employed in 85 joints. The literature shows pseudoarthrosis rates of 0 to 33%. This technique had a 2.3% failure rate that compares favorably with those in other published series.  相似文献   
27.
Plasma mianserin and desmethylmianserin concentrations were measured in 17 clinically depressed elderly patients after a single 30 mg dose of mianserin. The patients then received mianserin 30 mg daily for up to 6 weeks and the plasma concentrations were measured at weekly intervals. The relationship between concentrations of mianserin and desmethylmianserin at steady-state and at 16 and 24 hours after the single test dose was not good enough to be used for prediction of dosage requirements. Reasons for this finding are discussed.  相似文献   
28.
Linear IgA disease (LAD) is a rare acquired autoimmune bullous disorder, characterized by linear deposition of IgA along the dermoepidermal basement membrane zone. The clinical presentation of LAD consists of vesiculobullous lesions affecting the skin and mucosal surfaces. The present case report presents a rare presentation of this vesiculobullous disorder. Although more than 50% of LAD patients present with oral lesions, there are few reported cases of involvement of the mouth as the sole manifestation. A 79-year-old female presented with a sore mouth and erosions affecting the palate. The symptoms resolved following the provision of mycophenolate, an antiproliferative immunosuppressant which has not previously appeared to have been reported in the long-term successful management of linear IgA disease limited to the mouth. We found that mycophenolate is a useful adjunct to the successful treatment of oral linear IgA when the uses of other immunosuppressants are contraindicated.  相似文献   
29.
30.
Anti-S-100 Serum blocks long-term potentiation in the hippocampal slice   总被引:2,自引:0,他引:2  
S-100 is a calcium-binding, glial protein which has been shown to be involved in behavioral learning and memory tasks. Long-term potentiation (LTP) in the hippocampus is a long-lasting enhancement of synaptic efficacy evoked by repetitive afferent stimulation. When anti-S-100 serum is applied by pressure ejection onto the stratum radiatum of area CA1 of the hippocampal slice, the amplitude of the extracellularly recorded population spike is not affected. However, repetitive stimulation of the afferents during S-100 application failed to produce LTP. At a distant site in the same slice, LTP occurs normally. Preimmune normal rabbit serum had no effect on the development of LTP. It appears that S-100 protein is involved in the establishment of LTP.  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