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   530094篇
  免费   27748篇
  国内免费   494篇
耳鼻咽喉   6686篇
儿科学   16926篇
妇产科学   12547篇
基础医学   92639篇
口腔科学   12346篇
临床医学   48520篇
内科学   95463篇
皮肤病学   11870篇
神经病学   34052篇
特种医学   19774篇
外国民族医学   53篇
外科学   78072篇
综合类   7610篇
现状与发展   2篇
一般理论   107篇
预防医学   38541篇
眼科学   11938篇
药学   41422篇
  1篇
中国医学   1126篇
肿瘤学   28641篇
  2021年   3895篇
  2018年   5735篇
  2017年   4129篇
  2016年   4870篇
  2015年   5360篇
  2014年   7120篇
  2013年   10503篇
  2012年   15576篇
  2011年   17392篇
  2010年   9959篇
  2009年   8824篇
  2008年   15715篇
  2007年   17447篇
  2006年   16941篇
  2005年   16262篇
  2004年   15885篇
  2003年   15267篇
  2002年   14791篇
  2001年   22438篇
  2000年   22975篇
  1999年   18929篇
  1998年   5237篇
  1997年   4366篇
  1996年   4400篇
  1995年   4127篇
  1992年   14421篇
  1991年   15825篇
  1990年   15954篇
  1989年   15629篇
  1988年   14310篇
  1987年   14204篇
  1986年   13171篇
  1985年   12690篇
  1984年   9397篇
  1983年   8003篇
  1982年   4177篇
  1979年   8937篇
  1978年   6383篇
  1977年   5150篇
  1976年   5506篇
  1975年   6614篇
  1974年   7419篇
  1973年   7158篇
  1972年   6598篇
  1971年   6309篇
  1970年   5887篇
  1969年   5467篇
  1968年   5161篇
  1967年   4623篇
  1966年   3963篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
ObjectivesCocaine is the second most frequently used illicit drug worldwide (after cannabis), and cocaine use disorder (CUD)-related deaths increased globally by 80% from 1990 to 2013. There is yet to be a regulatory-approved treatment. Emerging preclinical evidence indicates that deep brain stimulation (DBS) of the nucleus accumbens may be a therapeutic option. Prior to expanding the costly investigation of DBS for treatment of CUD, it is important to ensure societal cost-effectiveness.AimsWe conducted a threshold and cost-effectiveness analysis to determine the success rate at which DBS would be equivalent to contingency management (CM), recently identified as the most efficacious therapy for treatments of CUDs.Materials and MethodsQuality of life, efficacy, and safety parameters for CM were obtained from previous literature. Costs were calculated from a societal perspective. Our model predicted the utility benefit based on quality-adjusted life-years (QALYs) and incremental-cost-effectiveness ratio resulting from two treatments on a one-, two-, and five-year timeline.ResultsOn a one-year timeline, DBS would need to impart a success rate (ie, cocaine free) of 70% for it to yield the same utility benefit (0.492 QALYs per year) as CM. At no success rate would DBS be more cost-effective (incremental-cost-effectiveness ratio <$50,000) than CM during the first year. Nevertheless, as DBS costs are front loaded, DBS would need to achieve success rates of 74% and 51% for its cost-effectiveness to exceed that of CM over a two- and five-year period, respectively.ConclusionsWe find DBS would not be cost-effective in the short term (one year) but may be cost-effective in longer timelines. Since DBS holds promise to potentially be a cost-effective treatment for CUDs, future randomized controlled trials should be performed to assess its efficacy.  相似文献   
52.
International Journal of Diabetes in Developing Countries -  相似文献   
53.

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   
54.
55.
56.
The current coronavirus disease (COVID‐19) outbreak, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has raised the possibility of potential neurotropic properties of this virus. Indeed, neurological sequelae of SARS‐CoV‐2 infection have already been reported and highlight the relevance of considering the neurological impact of coronavirus (CoV) from a translational perspective. Animal models of SARS and Middle East respiratory syndrome, caused by structurally similar CoVs during the 2002 and 2012 epidemics, have provided valuable data on nervous system involvement by CoVs and the potential for central nervous system spread of SARS‐CoV‐2. One key finding that may unify these pathogens is that all require angiotensin‐converting enzyme 2 as a cell entry receptor. The CoV spike glycoprotein, by which SARS‐CoV‐2 binds to cell membranes, binds angiotensin‐converting enzyme 2 with a higher affinity compared with SARS‐CoV. The expression of this receptor in neurons and endothelial cells hints that SARS‐CoV‐2 may have higher neuroinvasive potential compared with previous CoVs. However, it remains to be determined how such invasiveness might contribute to respiratory failure or cause direct neurological damage. Both direct and indirect mechanisms may be of relevance. Clinical heterogeneity potentially driven by differential host immune‐mediated responses will require extensive investigation. Development of disease models to anticipate emerging neurological complications and to explore mechanisms of direct or immune‐mediated pathogenicity in the short and medium term is therefore of great importance. In this brief review, we describe the current knowledge from models of previous CoV infections and discuss their potential relevance to COVID‐19.  相似文献   
57.
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed.  相似文献   
58.
59.
60.
OBJECTIVE: To determine if there is a diurnal pattern in the clinical symptoms of HELLP (Hemolysis, Elevated Liver enzymes, Low Platelets) syndrome. STUDY DESIGN: A retrospective study was performed in 134 pregnancies complicated by HELLP syndrome. The medical records were reviewed to describe each HELLP episode. Time of day was divided into three periods, day, evening, and night. The following parameters were categorized according to the time of day: onset of symptoms, consultation by the doctor, initial blood sampling, diagnosis and decrease of symptoms. Biochemical parameters at clinical presentation and consecutive changes within 24 h were recorded. RESULTS: In 65 pregnancies 77 HELLP episodes were well documented. Times of onset of symptoms and consultation by the doctor were significantly higher during the evening and night (p < 0.001), whereas times of diagnosis and decrease of symptoms occurred significantly more during the day (p < 0.001). In only 49.3% of the cases were diagnostic laboratory criteria met at clinical presentation. This was mainly due to platelet values in excess of 100 x 10(9)/l. Several hours later (median 8 h, range 2-23) the decrease in platelets occurred. CONCLUSIONS: A diurnal pattern exists in the clinical symptoms of HELLP syndrome that is characterized by an exacerbation during the night and recovery during the day. There is a considerable delay between the onset of symptoms and the fulfillment of diagnostic laboratory criteria.  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