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   1972982篇
  免费   150389篇
  国内免费   3546篇
耳鼻咽喉   29039篇
儿科学   62562篇
妇产科学   58168篇
基础医学   286983篇
口腔科学   56619篇
临床医学   170347篇
内科学   381393篇
皮肤病学   40429篇
神经病学   156338篇
特种医学   77650篇
外国民族医学   524篇
外科学   306739篇
综合类   47200篇
现状与发展   3篇
一般理论   539篇
预防医学   148854篇
眼科学   46286篇
药学   149954篇
  1篇
中国医学   3771篇
肿瘤学   103518篇
  2018年   17918篇
  2015年   17992篇
  2014年   25193篇
  2013年   38526篇
  2012年   52555篇
  2011年   55957篇
  2010年   32863篇
  2009年   30977篇
  2008年   53779篇
  2007年   58446篇
  2006年   58697篇
  2005年   57907篇
  2004年   56038篇
  2003年   54226篇
  2002年   52947篇
  2001年   85082篇
  2000年   87316篇
  1999年   74260篇
  1998年   21759篇
  1997年   19708篇
  1996年   19757篇
  1995年   18692篇
  1994年   17798篇
  1993年   16525篇
  1992年   61381篇
  1991年   60452篇
  1990年   59492篇
  1989年   57771篇
  1988年   53915篇
  1987年   53016篇
  1986年   50627篇
  1985年   48576篇
  1984年   36905篇
  1983年   31943篇
  1982年   19517篇
  1981年   17583篇
  1980年   16369篇
  1979年   36002篇
  1978年   25622篇
  1977年   21842篇
  1976年   20475篇
  1975年   22320篇
  1974年   26943篇
  1973年   26031篇
  1972年   24717篇
  1971年   22930篇
  1970年   21619篇
  1969年   20887篇
  1968年   19363篇
  1967年   17362篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The efficacy of radiology in evaluating dysphagia was studied in 86 patients by comparison to endoscopic findings. In the 66 patients with endoscopic abnormalities radiology was correct in 54, for a sensitivity of 82%. Sensitivity of radiology improved to 95% if mild esophagitis was excluded. In the 20 patients with normal endoscopy, radiology was normal in 18 (90%). Thus radiology proved to be a reliable means of evaluating the esophagus in patients with dysphagia.  相似文献   
992.
Ranitidine influences the uptake of oral midazolam.   总被引:1,自引:0,他引:1       下载免费PDF全文
In a randomised crossover study in volunteers plasma midazolam levels were estimated for 24 h following 15 mg by mouth, either preceded by no medication or following 24 h therapy with ranitidine. Administration of the H2-receptor blocker significantly increased bioavailability of the benzodiazepine and resulted in higher plasma levels for the first 6 h after taking midazolam. This was accompanied by a greater soporific effect.  相似文献   
993.
This report describes a model for identifying sets of teaching abilities considered to be effective for medical school teaching staff, based on roles teachers assume and functions they are expected to perform as instructors. The specification of these teaching abilities was the first step in the development of a comprehensive course on Medical Instruction at the Basic Institute of Medical and Agricultural Biology of the State University of Sao Paulo, Botucatu, Brazil, where the senior author is employed. The work was based on the assumption that medical school teachers are expected to assume a variety of teaching roles and that identification and specification of the abilities that define their roles can result in more effective and efficient teaching.  相似文献   
994.
Neurogenic bladder dysfunction, characterized by hesitancy, need to strain, decreased stream, and increased duration of urination, developed in 104 (63%) of 166 employees working in the manufacture of polyurethane foam. Highest rates of illness (69%) occurred in production workers, and no illness occurred in office or warehouse workers. Onset of the epidemic coincided with introduction of a catalyst, dimethylaminopropionitrile (DMAPN), and monthly case incidence rates increased as DMAPN use increased. Outbreak ceased abruptly when DMAPN use was stopped. Of eight patients who underwent neurourologic testing during recovery, seven lacked either detrusor reflex or normal sensation of bladder filling; seven had a subclinical sensory abnormality; three had prolonged sacral-evoked responses; and two of these three had limb motor neuropathies. Dimethylaminopropionitrile is unique among known neurotoxins in producing urinary symptoms more frequently than limb nerve symptoms.  相似文献   
995.
A crossover double-blind controlled trial was performed on 36 patients with rheumatoid arthritis to assess the necessity for serum salicylate monitoring in determining optimal dosage. There was no clinically or statistically significant increase in the clinical improvement of patients associated with serum monitoring but potentially toxic serum levels occurred without tinnitus when serum monitoring was not used.  相似文献   
996.
Twenty four volunteers who had been allergic to laboratory animals for some years were examined by means of a questionnaire paying particular attention to symptoms associated with rats and by serological and skin tests with extracts of rat urine (retrospective study). Nasal and eye symptoms were reported by 21 and 16 individuals respectively: 13 had asthma. Positive skin tests and high levels of specific IgE antibody to rat urine extract were found in 17 of the more severely affected individuals and this group included 12 of those with asthma. Latent periods of work with animals before symptoms appeared varied from 0.5 to 12 years. Also 148 individuals were studied during their first year of work with animals (prospective study). Symptoms developing during the year were reported by 15%, asthma by 2%. IgE antibody levels to rat urine were raised in 40% of affected and 6% of the unaffected individuals but there was no significant correlation between symptoms and either antibody levels or positive skin tests. Allergic symptoms developing during the first year of postemployment were, on the whole, much milder than those seen in the retrospective study. A tentative conclusion is that most individuals who become allergic to laboratory animals develop the condition in a mild form during their first year of employment but it appears probable that atopic individuals, although having an equal chance of developing allergy as compared with non-atopic individuals, may eventually progress to a more severe form of the disease.  相似文献   
997.
In comparative histological and cytological studies on 270 prostatic carcinoma patients highly and moderately differentiated tumors were found to be more frequent histologically than cytologically. An early and reliable sign of response to hormone therapy proved to be reticularization and vacuolization of the nuclear chromatin. Follow-up studies by means of multiple aspiration biopsies with cytologic examinations seem to be more reliable in prognostic terms than examination of the histological tumor structure.  相似文献   
998.
999.
1000.
用两株McAb及BA—ELISA法检测肺癌患者血清中肺癌相关抗原   总被引:1,自引:1,他引:0  
肿瘤患者血清中肿瘤相关抗原含量甚微,通常需要高度敏感的测定系统方能进行检测.生物素-亲和素系统(BSA)是近年来建立的一种生物反应放大系统,由于BSA亲合力高、特异性强反应迅速,故自70年代后期引入免疫技术以来,大大改善和丰富了免疫学试验,成为新的检测系统.本实验用生物素标记两株抗人肺癌McAb——Lc86aE4和Lc86aC5,建立了BA-ELISA方法,并对肺癌患者血清中肺癌相关抗原(lung carcinoma associated antigen,LAA)进行了检测,证实BA-ELISA法具有特异、敏感及重复性好等优点.  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