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   1799825篇
  免费   132950篇
  国内免费   2989篇
耳鼻咽喉   26053篇
儿科学   55516篇
妇产科学   49823篇
基础医学   257404篇
口腔科学   51991篇
临床医学   159234篇
内科学   340516篇
皮肤病学   38734篇
神经病学   140812篇
特种医学   71887篇
外国民族医学   370篇
外科学   277394篇
综合类   43318篇
现状与发展   3篇
一般理论   508篇
预防医学   133386篇
眼科学   42374篇
药学   140663篇
  7篇
中国医学   4075篇
肿瘤学   101696篇
  2018年   17337篇
  2016年   15462篇
  2015年   17613篇
  2014年   24601篇
  2013年   36543篇
  2012年   49688篇
  2011年   52390篇
  2010年   30689篇
  2009年   28828篇
  2008年   48899篇
  2007年   52710篇
  2006年   53173篇
  2005年   51329篇
  2004年   49696篇
  2003年   47757篇
  2002年   46128篇
  2001年   86891篇
  2000年   88993篇
  1999年   74761篇
  1998年   20083篇
  1997年   18051篇
  1996年   17989篇
  1995年   16930篇
  1994年   15762篇
  1993年   14917篇
  1992年   59316篇
  1991年   57515篇
  1990年   56531篇
  1989年   54582篇
  1988年   50141篇
  1987年   49076篇
  1986年   46442篇
  1985年   44257篇
  1984年   32988篇
  1983年   28167篇
  1982年   16559篇
  1981年   14799篇
  1979年   31513篇
  1978年   21977篇
  1977年   19151篇
  1976年   17057篇
  1975年   19024篇
  1974年   22879篇
  1973年   22005篇
  1972年   21007篇
  1971年   19635篇
  1970年   18419篇
  1969年   17889篇
  1968年   16007篇
  1967年   14538篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
941.
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   
942.
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   
943.
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   
944.
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   
945.
Although many studies as well as conventional wisdom suggest that increases in income result in improved diet and nutritional status in rural areas of developing countries, several recent studies have failed to demonstrate such a relationship. In this paper the relationships between material wealth and income and dietary strategies are examined for an agricultural community in rural Mexico. A superficial examination focusing on summary indices of dietary adequacy frequently cited in the literature and indices of wealth and income demonstrates a positive relationship between them in this community. However, an examination of the same data emphasizing alternative dietary strategies to achieve nutritional adequacy shows a more complex picture. Increasing income is associated with consumption of purchased foods especially foods of animal origin, and is not associated with the consumption of staple foods produced within the household. Diets dependent on purchased foods do not necessarily meet nutritional needs more adequately than diets which rely on agricultural products and gathered foods. Among the implications of this research are a need for a method of analysis which focuses on alternative nutritional strategies available in particular settings, and a need to reassess the relative importance of income generating activities and subsistence agriculture in areas undergoing agricultural change.  相似文献   
946.
947.
948.
Seventy seven antral biopsies were collected from patients attending endoscopy clinic at King Khalid University Hospital, Riyadh, Saudi Arabia during a period of six months between December 1988 to May 1989. Of these 69 (89.6%) showed chronic gastritis as well as Helicobacter-like organisms (HLOs) in the biopsy specimens while 63 (81.8%) of biopsies grew Helicobacter pylori on culture. These findings indicate a good correlation between the histological diagnosis of chronic gastritis and isolation of H. pylori on culture.  相似文献   
949.
To measure prefrontal and subcortical activity during a cognitive task, we examined 19 newly diagnosed schizophrenics and patients with schizophreniform psychosis. Seven healthy volunteers served as controls. The patients were drug naive or had received neuroleptics for a few days only. Cerebral blood flow distribution was depicted by single photon emission computed tomography at rest and during activation with the Wisconsin Card Sorting Test. A significant relative activation deficit in the left inferior-prefrontal region was revealed during the Wisconsin Card Sorting Test in the patient group. Furthermore, the patients had impaired striatal suppression on the left side during the cognitive task. The test performance was significantly impaired in the patients. The inability to reduce striatal activity may be due to a lack of corticostriatal feedback during prefrontal activation.  相似文献   
950.
Blood bank staff, 8 out of 25 (32%) have been exposed to hepatitis B virus (HBV) and the prevalence of HBV markers in blood bank employees handling high risk subjects show hepatitis B surface antigen (n = 1), hepatitis B surface antibody (n = 7), hepatitis B core antibody (n = 6) and combined hepatitis B surface antibody and hepatitis B core antibody (n = 6) seropositivity but all are negative to human immunodeficiency virus (HIV). Serum alanine aminotransferase was raised in the employees than normal subjects and it is suggestive of sub-clinical hepatitis. The employees of blood bank should be trained for proper handling of test materials and must be periodically monitored for HBV and HIV. Immunisation for HBV is mandatory only for the employees of transfusion centre which handles high risk subjects.  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