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   1741篇
  免费   106篇
  国内免费   29篇
耳鼻咽喉   13篇
儿科学   44篇
妇产科学   17篇
基础医学   123篇
口腔科学   32篇
临床医学   162篇
内科学   593篇
皮肤病学   21篇
神经病学   96篇
特种医学   60篇
外科学   299篇
综合类   25篇
一般理论   1篇
预防医学   115篇
眼科学   44篇
药学   114篇
中国医学   7篇
肿瘤学   110篇
  2021年   17篇
  2020年   9篇
  2019年   16篇
  2018年   30篇
  2017年   18篇
  2016年   24篇
  2015年   19篇
  2014年   31篇
  2013年   57篇
  2012年   62篇
  2011年   57篇
  2010年   58篇
  2009年   43篇
  2008年   71篇
  2007年   100篇
  2006年   91篇
  2005年   74篇
  2004年   81篇
  2003年   71篇
  2002年   68篇
  2001年   82篇
  2000年   52篇
  1999年   61篇
  1998年   28篇
  1997年   32篇
  1996年   29篇
  1995年   23篇
  1994年   27篇
  1993年   24篇
  1992年   45篇
  1991年   41篇
  1990年   46篇
  1989年   34篇
  1988年   32篇
  1987年   28篇
  1986年   27篇
  1985年   20篇
  1984年   21篇
  1983年   17篇
  1982年   12篇
  1981年   12篇
  1980年   8篇
  1974年   8篇
  1973年   10篇
  1970年   9篇
  1958年   14篇
  1957年   13篇
  1956年   10篇
  1955年   12篇
  1954年   15篇
排序方式: 共有1876条查询结果,搜索用时 15 毫秒
1.
Four children treated for seizures between 1980 and 1986 were diagnosed as having Landau-Kleffner syndrome (acquired aphasia with convulsive disorder), following the onset of aphasia. They received early and prolonged ACTH or corticosteroid therapy, with high initial doses. In all four cases the EEG promptly became normal, with subsequent long-lasting remission of the aphasia and improvement of seizure control. Three to six years after discontinuation of hormone therapy the children are off medication and free from seizures and language disability.  相似文献   
2.
3.
4.
To examine the relationship between demographic, clinical and psychosocial variables and diabetes self-care management in Mexican type 2 diabetic patients. Cross-sectional study of 176 consecutive patients with type 2 diabetes aged 30-75 years, attending a tertiary health-care center in Mexico City. A brief medical history and previously validated questionnaires were completed. The study group consisted of 64 males/112 females, aged 55 +/- 11 years, mean diabetes duration of 12 +/- 8 years and HbA1c of 9.0 +/- 2.0%, 78.4% reported following the correct dose of diabetes pills or insulin, 58% ate the recommended food portions, and 44.3% did exercise three or more times per week. A good adherence to these three recommendations was observed in only 26.1% of the patients. These patients considered as a group were characterized by a greater knowledge about the disease (P < 0.00001), regular home blood glucose monitoring (P < 0.01), an inner perception of better diabetes control (P = 0.007), good health (P = 0.004) and better communication with their physician (P < 0.02). A poor adherence to two or the three main diabetes care recommendations was associated with a depressive state (OR 2.38, 95% CI 1.1-4.9, P < 0.01) and a history of excessive alcohol intake (OR 4.03, 95% CI 1.1-21.0, P = 0.03). Poor adherence to standard diabetes care recommendations is frequently observed in patients with type 2 diabetes attending a specialized health care center in Mexico City. Depression must be identified and treated effectively.  相似文献   
5.
In order to explore which amino acids or which blocks of amino acids in the 29 amino acid neuropeptide galanin are important for recognition of the endogenous ligand by galanin receptor subtypes present in the jejunum and in the hypothalamus, respectively, we have carried out L-Ala substitutions of individual amino acids or of blocks of amino acids in the rat galanin sequence and examined the binding of the obtained analogs to the rat hypothalamic and jejunal galanin receptor subtypes. This study reveals that the galanin sequence YLLGPH9–14 is essential for recognition of galanin by both the rat hypothalamic and jejunal galanin receptor subtypes. Substitution of the N-terminal amino acids, GWTL1–4, leads to total loss of affinity of galanin for both hypothalamic and jejunal galanin receptors. The α-helical C-terminal amino acid (25–29) part of galanin has no greater influence on the affinity of galanin to the hypothalamic galanin receptor subtype. L-Ala substitution of the C-terminal amino acids of galanin KHGLT25–29 shows, however, that this C-terminal motif is essential for the recognition by the jejunal galanin receptor subtype, whereas amino acids in the middle portion of galanin NSAG5–8 are of importance for binding to the hypothalamic but not to the jejunal receptor. [Ala5–8] Galanin thus has a more than 100-fold higher affinity to jejunal receptor than to the hypothalamic receptor, while [Ala25–29] galanin has a more than 100-fold higher affinity for the hypothalamic than for jejunal galanin receptor subtypes. pH dependence of the galanin binding to these receptor subtypes is also different. © Munksgaard 1997.  相似文献   
6.
7.
BACKGROUND: Apical ballooning syndrome (ABS) is a poorly understood clinical entity characterized by acute, transient systolic dysfunction of the left ventricular (LV) apex in the absence of epicardial coronary artery disease and commonly associated with acute emotional stress. We report abnormal regional myocardial perfusion and glucose uptake in 4 consecutive ABS patients studied using positron emission tomography with 13N-ammonia and 18F-fluorodeoxyglucose within 72 hours of presentation with ABS. METHODS: All patients were postmenopausal females, 3 of whom had a major recent life stress event. Coronary angiography revealed no or minimal obstructive epicardial coronary artery disease. All patients exhibited reduced glucose uptake in the mid-LV and apical myocardial segments, which was out of proportion to perfusion abnormalities in half of the cases. CONCLUSION: In all 4 patients, affected regions subsequently recovered regional LV systolic function within 6 weeks.  相似文献   
8.
Administration of theophylline to asthmatic children is frequently associated with an adverse influence on their behavior. The efficacy and behavioral effects of the administration of high-dose theophylline (T) and ketotifen (K) in various combinations were evaluated prospectively in a double-blind, placebo controlled study in 55 children with moderately severe perennial asthma. During a baseline period of 2 weeks, theophylline (serum level of 10-20 μg/ml) was administered to all the children. After this period the patients were randomly allocated into four comparable groups. The children were treated during a 12-week period with: T + K-Placebo (T group); T + K (T + K group); half-dose T + K (T/ 2 + K group); or placebo of both T and K (P group). During the 12-week treatment period, as compared to the baseline period, only the three groups of children who received active therapy (T + P, T + K, T/2 + K) showed a similar reduction in the number of days with asthmatic symptomatology, improvement of the total asthmatic symptoms score, and increased PEFR. The behavioral activity of the children (assessed by the Conner's rating scale) improved significantly only in the groups receiving placebo or T/2 + K. The results of this study suggest that a combination therapy of half the recommended therapeutic dose of theophylline with ketotifen can be clinically as effective as therapy with a full dose of theophylline, but with significantly less adverse behavioral effects.  相似文献   
9.
Nonneural granular cell tumors (NNGCTs) are rare benign neoplasms originally described in 1991 by Leboit et al. Typical granular cell tumors (GCTs) are commonly encountered in the oral cavity, but NNGCTs, unlike GCTs, are S-100 negative and may display cytologic atypia, allowing for misdiagnosis as a more aggressive lesion. We report a case of a 43-year-old male with a lesion of the mandible that we believe to be the first intraoral example of an NNGCT.  相似文献   
10.
Breast screening practices among primary physicians: reality and potential   总被引:1,自引:0,他引:1  
Increased use of regular screening mammograms and clinical breast examinations (CBE) among women aged 40 years and more could have a dramatic impact on mortality from breast cancer, but patient and physician barriers to mammography impede its acceptance. We conducted a survey of 300 primary care physicians to assess their knowledge, attitudes, beliefs, and breast screening practices. Our results show that only 71 percent of the respondents ordered mammograms for all women aged 50 to 75 years, which is the recommendation by the National Cancer Institute and American Cancer Society. Approximately 46 percent of respondents performed CBE on all women patients aged 50 to 75 years. Inadequate patient insurance coverage, equivocal radiology reports, patient reluctance or worry, and patient embarrassment all appear to be barriers to physicians' utilization of breast screening.  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