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   142篇
  免费   28篇
  国内免费   7篇
儿科学   7篇
妇产科学   1篇
基础医学   44篇
口腔科学   3篇
临床医学   17篇
内科学   17篇
神经病学   2篇
特种医学   27篇
外科学   9篇
综合类   2篇
预防医学   13篇
药学   27篇
  1篇
肿瘤学   7篇
  2023年   1篇
  2021年   2篇
  2020年   2篇
  2017年   1篇
  2016年   3篇
  2015年   6篇
  2014年   4篇
  2013年   4篇
  2012年   5篇
  2011年   3篇
  2010年   4篇
  2009年   9篇
  2008年   7篇
  2007年   11篇
  2006年   3篇
  2005年   9篇
  2004年   2篇
  2003年   2篇
  2002年   3篇
  2001年   4篇
  1999年   3篇
  1998年   5篇
  1997年   4篇
  1996年   10篇
  1995年   4篇
  1994年   6篇
  1993年   3篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1989年   5篇
  1988年   9篇
  1987年   4篇
  1986年   5篇
  1985年   5篇
  1984年   4篇
  1983年   3篇
  1982年   6篇
  1981年   1篇
  1980年   2篇
  1978年   1篇
  1977年   2篇
  1975年   1篇
  1971年   1篇
  1965年   1篇
  1960年   1篇
排序方式: 共有177条查询结果,搜索用时 10 毫秒
81.
Regional wall motion (RWM) abnormalities are sensitive indicators of left ventricular (LV) dysfunction, but quantitation of RWM with gated radionuclide ventriculography (RVG) has been limited, particularly in the left anterior oblique (LAO) projection. Regional LV performance was studied in 18 patients undergoing LAO RVG immediately prior to contrast ventriculography (CVG). Wall motion was analyzed by semiautomated and visual methods using several coordinate systems. For semiautomated methods, RVG and CVG wall motion were closely related in the two 90 degrees polar sectors at the apex and posterior wall (r = .85) and in the five 45 degrees polar sectors from midseptum through posterior wall (r = .82). The basal sectors on RVG had weak relationship to CVG, due to adjacent vascular structures. Semiautomated and visual grades for polar sectors on both CVG and RVG were closely related (r = .88- .94). Measured regional wall motion on LAO RVG compared favorably with near-simultaneous CVG in nonoverlapping portions of the LV and allowed objective quantitation of regional LV performance.  相似文献   
82.
PDQ is an online database that provides information about the prognosis and treatment of all major types of cancer. It represents a major effort by the NCI to communicate advances in cancer treatment using computer technology, and serves as a major component of the Institute's program to reduce cancer mortality nationwide. PDQ utilizes a modern large-scale computer to provide processing speed, a general purpose database management system to provide retrieval and display functions, and commercial telecommunication networks to provide online access to up-to-date information on cancer treatment. A series of user-friendly menus allow searching, browsing, and displaying without having to learn a specialized search language. PDQ is accessible through the National Library of Medicine's computer system via a computer terminal or personal computer and is available to the medical community at over 2000 medical libraries and centers and through individual access codes. PDQ is also available as an online database under a special license agreement with NCI through two medical information systems produced by commercial database vendors: BRS/Saunders' COLLEAGUE and Mead Data Central's MEDIS.  相似文献   
83.

Background  

Major international differences in heart failure treatment have been repeatedly described, but the reasons for these differences remain unclear. National guideline recommendations might be a relevant factor. This study, therefore, explored variation of heart failure guideline recommendations in Europe.  相似文献   
84.
85.
The bilateral limb deficit (BLD) describes the difference in maximal or near-maximal force generating capacity of muscles when they are contracted alone and in combination with the contralateral muscles. This study examined the effects of a 6-week (three times per week) bilateral leg strength training programme on BLD in younger and older adults. Data were collected from 33 subjects during slow (45°/s) isokinetic knee extensions and flexions before and after the training programme. After training, the BLD was reduced for extension (73.3–86.9%; P<0.001) but not for flexion (67.5–71.2%; P=0.13) regardless of age and gender. This study suggests that difficulty in recruiting all muscle units during a task involving bilateral activation can be improved by training, although such an effect appears to depend on the muscle group appreciated.  相似文献   
86.
The latissimus dorsi muscle, one of the largest muscles in the human body, has gained widespread popularity in microsurgical reconstruction. Because the latissimus serves to adduct and medially rotate the upper extremity, caution in its use has been advocated in handicapped and non-ambulatory patients, although a paucity of information exists in the literature. The purpose of this reported project was to determine whether the loss of the latissimus dorsi could be documented objectively or subjectively, either in the preoperative condition or post-harvesting in the handicapped patients. Two paraplegic patients were studied. Results indicate a lack of objective functional deficit; this includes both the nerve-blocked state and the postoperative condition. In addition, both patients failed to demonstrate the need to change any activities of daily living. This evidence suggests that, although careful decisions must be made on a case-by-case basis, the use of the latissimus dorsi muscle is not necessarily contraindicated in this group of patients.  相似文献   
87.

Background

Some UK GPs are acquiring access to natriuretic peptide (NP) testing or echocardiography as diagnostic tests for heart failure. This study developed appropriateness ratings for the diagnostic application of these tests in routine general practice.

Aim

To develop appropriateness ratings for the diagnostic application of NP testing or echocardiography for heart failure in general practice.

Design and setting

An appropriateness ratings evaluation in UK general practice.

Method

Four presenting symptoms (cough, bilateral ankle swelling, dyspnoea, fatigue), three levels of risk of cardiovascular disease (low, intermediate, high), and dichotomous categorisations of cardiovascular/chest examination and electrocardiogram result, were used to create 540 appropriateness scenarios for patients in whom NP testing or echocardiography might be considered. These were rated by a 10-person expert panel, consisting of GPs and GPs with specialist interests in cardiology, in a two-round RAND Appropriateness Method.

Results

Onward referral for NP testing or echocardiography was rated as an appropriate next step in 217 (40.2%) of the 540 scenarios; in 194 (35.9%) it was rated inappropriate. The ratings also show where NP testing or echocardiography were ranked as equivalent next steps and when one test was seen as the more appropriate than the other.

Conclusion

NP testing should be the routine test for suspected heart failure where referral for diagnostic testing is considered appropriate. An abnormal electrocardiogram status makes referral to echocardiography an accompanying, or more appropriate, next step alongside NP testing, especially in the presence of dyspnoea. Abnormal NP testing should subsequently be followed up with referral for echocardiography.  相似文献   
88.
Clinical gait analysis aims to quantify and assess the mechanics of walking and identify deviations from ‘normal’ movement patterns. To facilitate the use of clinical equipment, protocols are required to process data and produce a few meaningful summary measurements which can, in turn, be used to flag gait abnormalities. Earlier work produced a one-dimensional index of gait, calculated from sagittal hip, knee and ankle rotation angle patterns. The objective of this study was to extend the original index, incorporating kinematic and kinetic data from multiple planes, while allowing for correlations between component measures. A one-dimensional index of normal gait was developed, based on normative gait data (N = 45 children, aged 3–13 years). The new one-dimensional index was calculated using correlation patterns between seven component indices, each of which has diagnostic interpretation. The effectiveness of the new index was tested using immature normative data (N = 14) and hypotonic data (N = 10). Approximately 85% of immature normative children and 100% of hypotonic children were classified as either unusual or extreme by the one-dimensional index. These data reduction protocols improve objective gait analyses in the clinical setting.  相似文献   
89.

Background

Management of pharyngitis is commonly based on features which are thought to be associated with Lancefield group A beta-haemolytic streptococci (GABHS) but it is debatable which features best predict GABHS. Non-group A strains share major virulence factors with group A, but it is unclear how commonly they present and whether their presentation differs.

Aim

To assess the incidence and clinical variables associated with streptococcal infections.

Design and setting

Prospective diagnostic cohort study in UK primary care.

Method

The presence of pathogenic streptococci from throat swabs was assessed among patients aged ≥5 years presenting with acute sore throat.

Results

Pathogenic streptococci were found in 204/597 patients (34%, 95% CI = 31 to 38%): 33% (68/204) were non-group A streptococci, mostly C (n = 29), G (n = 18) and B (n = 17); rarely D (n = 3) and Streptococcus pneumoniae (n = 1). Patients presented with similar features whether the streptococci were group A or non-group A. The features best predicting A, C or G beta-haemolytic streptococci were patient’s assessment of severity (odds ratio [OR] for a bad sore throat 3.31, 95% CI = 1.24 to 8.83); doctors’ assessment of severity (severely inflamed tonsils OR 2.28, 95% CI = 1.39 to 3.74); absence of a bad cough (OR 2.73, 95% CI = 1.56 to 4.76), absence of a coryza (OR 1.54, 95% CI = 0.99 to 2.41); and moderately bad or worse muscle aches (OR 2.20, 95% CI = 1.41 to 3.42).

Conclusion

Non-group A strains commonly cause streptococcal sore throats, and present with similar symptomatic clinical features to group A streptococci. The best features to predict streptococcal sore throat presenting in primary care deserve revisiting.  相似文献   
90.
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