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   380460篇
  免费   14086篇
  国内免费   1620篇
耳鼻咽喉   5519篇
儿科学   13194篇
妇产科学   10670篇
基础医学   50356篇
口腔科学   12164篇
临床医学   28127篇
内科学   76253篇
皮肤病学   10369篇
神经病学   27374篇
特种医学   14917篇
外国民族医学   112篇
外科学   52362篇
综合类   3762篇
现状与发展   4篇
一般理论   46篇
预防医学   35190篇
眼科学   8281篇
药学   27427篇
  12篇
中国医学   1434篇
肿瘤学   18593篇
  2022年   2523篇
  2021年   5305篇
  2020年   3005篇
  2019年   4780篇
  2018年   9594篇
  2017年   7773篇
  2016年   7032篇
  2015年   8808篇
  2014年   9875篇
  2013年   11409篇
  2012年   21462篇
  2011年   17487篇
  2010年   9237篇
  2009年   9606篇
  2008年   12235篇
  2007年   13214篇
  2006年   13136篇
  2005年   20834篇
  2004年   21525篇
  2003年   16482篇
  2002年   11395篇
  2001年   9944篇
  2000年   7732篇
  1999年   10459篇
  1998年   1969篇
  1992年   8796篇
  1991年   8953篇
  1990年   9014篇
  1989年   8393篇
  1988年   7784篇
  1987年   7476篇
  1986年   7112篇
  1985年   6384篇
  1984年   4474篇
  1983年   3683篇
  1982年   1481篇
  1979年   4654篇
  1978年   2916篇
  1977年   2244篇
  1976年   2024篇
  1975年   3038篇
  1974年   3845篇
  1973年   3480篇
  1972年   3364篇
  1971年   3303篇
  1970年   3143篇
  1969年   3042篇
  1968年   2789篇
  1967年   2664篇
  1966年   2332篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
CD4+CD25+ regulatory T cells in irritable bowel syndrome patients   总被引:3,自引:0,他引:3  
  相似文献   
992.
993.
We report a case of transient nonketotic hyperglycinaemia in which radiography correlated closely with clinical and biochemical findings. Only 5 patients have been previously described with this transient form of nonketotic hyperglycinaemia. Among the radiographic findings, thinning of the corpus callosum is the most characteristic. Received: 26 June 1996 Accepted: 29 November 1996  相似文献   
994.
Evolution of bronchial reactivity was examined in a sample of aluminium potroom workers exposed to a variety of respiratory irritants in concentrations below the MAC values for Yugoslavia (hydrogen fluoride, particulate fluorides, sulphur dioxide). Lung function indices and bronchial reactivity were measured in 24 workers continuously employed in an aluminium plant and in nine workers who had ceased to work in the plant. Measurements took place over a two-year interval. A sustained level of bronchial reactivity was recorded in both examined groups regardless of occupational practice. Even in workers with dyspnoea and airway obstruction bronchial reactivity did not worsen in spite of continuous exposure. Avoidance of exposure to potroom fumes did not bring about any significant improvement of reactivity, moreover, bronchial reactivity deteriorated in one worker. Owing to discordance between spirometric values and bronchial reactivity, a follow-up of workers removed from harmful occupational exposure is suggested.  相似文献   
995.
Hereditary complete deficiency of the fourth component of complement (C4) is an extremely rare disorder with 17 cases reported so far. Twelve of these patients suffered from a systemic-lupus-erythematosus-like illness. The patient we here describe presented with severe Henoch-Sch?nlein purpura (HSP) at the age of 17. Immunofluorescence of a kidney biopsy showed granular deposits of IgG, IgA, IgM, C3 and fibrinogen in the mesangium and segmentally along the basement membrane. Six years later, the patient developed hypertension and nephrotic syndrome. Renal function deteriorated rapidly. He was on hemodialysis for 12 months and then received a cadaveric kidney graft. After 2 years of uncomplicated course, microhematuria and proteinuria developed. Immunofluorescence of a transplant biopsy was virtually identical to the pattern in the patient's own kidneys. We thus conclude that the patient had recurrence of his primary disease in the graft. Three and a half years after transplantation hemodialysis had to be restarted. This unique case supports the current view that deficiency of classical pathway components predisposes to the development of immune complex diseases and that the complement system is activated via the alternate pathway in HSP. Furthermore, we assume that complete C4 deficiency was the major cause for the recurrence and unfavorable outcome of HSP in the graft.  相似文献   
996.
The article deals with the results of complex study of the effect of pulmonary insufficiency on intracardiac hemodynamics and function of the heart in the immediate and late-term periods after radical correction of Fallot's tetralogy. Answers are also given to questions concerning the expediency of the use and functional adequacy of a xeno-pericardial monocusp in the closure mechanism of the pulmonary artery valve. The study showed that massive pulmonary regurgitation has a negative effect on the functional condition of the right ventricle in late-term postoperative periods. Convincing data were obtained which allow a graft with a monocusp of a bull's pericardium to be recommended for further clinical use to prevent insufficiency of the pulmonary artery valve after radical correction of Fallot's tetralogy.  相似文献   
997.
A patellar brace with a lateral pad was used in 25 patients with unilateral retropatellar pain syndrome. The patients were told to use the brace in activities that loaded the patella, and they were followed for 1 to 2 years. At follow-up, 8 patients were improved, while the symptoms were unchanged or worse in 17. The level of activity was increased in 4 patients, reduced in 3, and unchanged in the others. It is concluded that treatment with a patellar brace with a lateral pad is not likely to succeed in the majority of patients with retropatellar pain syndrome.  相似文献   
998.
Mercury exposure of different origins among dentists and dental nurses   总被引:2,自引:0,他引:2  
Mercury exposure was studied among dental personnel with the use of urinary mercury excretion rates and questionnaires. The study covered 314 dentists and dental nurses employed in public clinics and private practices in Stockholm. The obtained urinary mercury excretion rates were analyzed by stepwise regression for assigning them to different origins, such as environmental factors, number of amalgam surfaces, chewing of gum, kind of employment and profession, age, sex, amalgam handling time, and use of amalgam capsules. On the average the occupational contribution to the total urinary mercury excretion rate was small and of the same order as the contribution from their own amalgam fillings (approximately 2 micrograms of mercury/24 h). There were, however, individuals showing excretion rates close to the levels at which effects on the central nervous system and the kidneys have been reported.  相似文献   
999.
The contrast sensitivity function (CSF) and visual acuity were determined in children and adults with unilateral amblyopia due to strabismus or anisometropia with central fixation. The preschool children were examined repeatedly during occlusion treatment. All amblyopes had CSF deficits. The CSF was characterised by its peak value (the maximal sensitivity, Smax, and the spatial frequency at which Smax occurs, Frmax) calculated by a single peak least-square regression method. The two amblyopic groups showed discrepancies in relationship of both Smax and Frmax versus visual acuity both initially and during treatment. The strabismic cases had a more marked visual acuity deficit in relation to the contrast sensitivity losses, whereas these parameters are affected similarly in anisometropic amblyopes. The relationship between recovery of visual acuity and CSF during the initial month of occlusion treatment was of prognostic significance for the outcome of visual acuity improvement.  相似文献   
1000.
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