收费全文 | 180926篇 |
免费 | 9928篇 |
国内免费 | 263篇 |
耳鼻咽喉 | 2898篇 |
儿科学 | 5872篇 |
妇产科学 | 3945篇 |
基础医学 | 26250篇 |
口腔科学 | 4971篇 |
临床医学 | 15888篇 |
内科学 | 34267篇 |
皮肤病学 | 4404篇 |
神经病学 | 18271篇 |
特种医学 | 7475篇 |
外科学 | 28279篇 |
综合类 | 1454篇 |
现状与发展 | 1篇 |
一般理论 | 79篇 |
预防医学 | 10986篇 |
眼科学 | 3580篇 |
药学 | 12284篇 |
中国医学 | 257篇 |
肿瘤学 | 9956篇 |
2023年 | 1035篇 |
2022年 | 966篇 |
2021年 | 2361篇 |
2020年 | 1793篇 |
2019年 | 2437篇 |
2018年 | 4189篇 |
2017年 | 3366篇 |
2016年 | 4221篇 |
2015年 | 3987篇 |
2014年 | 4650篇 |
2013年 | 7554篇 |
2012年 | 10428篇 |
2011年 | 11432篇 |
2010年 | 6423篇 |
2009年 | 4756篇 |
2008年 | 10943篇 |
2007年 | 11445篇 |
2006年 | 11090篇 |
2005年 | 11027篇 |
2004年 | 10231篇 |
2003年 | 10168篇 |
2002年 | 9821篇 |
2001年 | 5640篇 |
2000年 | 6981篇 |
1999年 | 4050篇 |
1998年 | 1942篇 |
1997年 | 1620篇 |
1996年 | 1275篇 |
1995年 | 1113篇 |
1994年 | 1045篇 |
1993年 | 988篇 |
1992年 | 941篇 |
1991年 | 792篇 |
1990年 | 761篇 |
1989年 | 768篇 |
1988年 | 655篇 |
1987年 | 718篇 |
1986年 | 610篇 |
1985年 | 818篇 |
1984年 | 786篇 |
1983年 | 675篇 |
1982年 | 736篇 |
1981年 | 713篇 |
1980年 | 627篇 |
1979年 | 559篇 |
1978年 | 514篇 |
1977年 | 544篇 |
1976年 | 462篇 |
1975年 | 462篇 |
1974年 | 415篇 |
Introduction
The nature of community pharmacy is changing, shifting from the preparation and distribution of medicines to the provision of cognitive pharmaceutical services (CPS); however, often the provision of traditional services leaves little time for innovative services. This study investigated the time community pharmacists spend on the tasks and activities of daily practice and to what extent they are able to implement CPS-related services in daily practice.Methods
Self-reporting work sampling was used to register the activities of community pharmacists. A smartphone application, designed specifically for this purpose, alerted participants to register their current activity five times per working day for 6 weeks. Participants also completed an online survey about baseline characteristics.Results
Ninety-one Dutch community pharmacists provided work-sampling data (7848 registered activities). Overall, 51.5% of their time was spent on professional activities, 35.4% on semi-professional activities, and 13.1% on non-professional activities. The proportion of time devoted to CPS decreased during the workweek, whereas the time spent on traditional task increased.Discussion and conclusion
This study shows it is feasible to collect work-sampling data using smartphone technology. Community pharmacists spent almost half of their time on semi-professional and non-professional activities, activities that could be delegated to other staff members. In practice, the transition to CPS is hampered by competing traditional tasks, which prevents community pharmacists from profiling themselves as pharmaceutical experts in daily practice. 相似文献Background
Lung ultrasound can accelerate the diagnosis of life-threatening diseases in adults with respiratory symptoms.Objective
Systematically review the accuracy of lung ultrasonography (LUS) for emergency diagnosis of pneumonia, acute heart failure, and exacerbation of chronic obstructive pulmonary disease (COPD)/asthma in adults.Methods
PubMed, Embase, Scopus, Web of Science, and LILACS (Literatura Latino Americana e do Caribe em Ciências da Saúde; until 2016) were searched for prospective diagnostic accuracy studies. Rutter-Gatsonis hierarchical summary receiver operating characteristic method was used to measure the overall accuracy of LUS and Reitsma bivariate model to measure the accuracy of the different sonographic signs. This review was previously registered in PROSPERO (Centre for Reviews and Dissemination, University of York, York, UK; CRD42016048085).Results
Twenty-five studies were included: 14 assessing pneumonia, 14 assessing acute heart failure, and four assessing exacerbations of COPD/asthma. The area under the summary receiver operating characteristic curve of LUS was 0.948 for pneumonia, 0.914 for acute heart failure, and 0.906 for exacerbations of COPD/asthma. In patients suspected to have pneumonia, consolidation had sensitivity of 0.82 (95% confidence interval [CI] 0.74–0.88) and specificity of 0.94 (95% CI 0.85–0.98) for this disease. In acutely dyspneic patients, modified diffuse interstitial syndrome had sensitivity of 0.90 (95% CI 0.87–0.93) and specificity of 0.93 (95% CI 0.91–0.95) for acute heart failure, whereas B-profile had sensitivity of 0.93 (95% CI 0.72–0.98) and specificity of 0.92 (95% CI 0.79–0.97) for this disease in patients with respiratory failure. In patients with acute dyspnea or respiratory failure, the A-profile without PLAPS (posterior-lateral alveolar pleural syndrome) had sensitivity of 0.78 (95% CI 0.67–0.86) and specificity of 0.94 (95% CI 0.89–0.97) for exacerbations of COPD/asthma.Conclusion
Lung ultrasound is an accurate tool for the emergency diagnosis of pneumonia, acute heart failure, and exacerbations of COPD/asthma. 相似文献Background
We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.Methods
In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).Results
After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).Conclusions
This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy. 相似文献The presence of noise, the variations in the background and the temporal variation of the fluorescence level pose serious problems in obtaining a robust registration of the retinal images. Moreover, local search strategies are not robust in the case of ICG angiograms, even if one uses a multiresolution approach.
The present work makes a systematic comparison of different optimization techniques, namely the minimization method derived from the optical flow formulation, the Nelder-Mead local search and the HCIAC ant colony metaheuristic, each optimizing a similarity criterion for the gradient images. The impact of the resolution and median filtering of gradient image is studied and the robustness of the approaches is tested through experimental studies, performed on macular fluorescein and ICG angiographies.
Our proposed optimization techniques have shown interesting results especially for high resolution difficult registration problems. Moreover, this approach seems promising for affine (6-parameter motion model) or elastical registrations. 相似文献