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   1182篇
  免费   81篇
  国内免费   9篇
耳鼻咽喉   15篇
儿科学   76篇
妇产科学   11篇
基础医学   96篇
口腔科学   31篇
临床医学   124篇
内科学   277篇
皮肤病学   21篇
神经病学   30篇
特种医学   265篇
外科学   80篇
综合类   59篇
预防医学   62篇
眼科学   29篇
药学   51篇
中国医学   9篇
肿瘤学   36篇
  2023年   2篇
  2021年   5篇
  2020年   9篇
  2019年   11篇
  2018年   15篇
  2017年   13篇
  2016年   10篇
  2015年   22篇
  2014年   41篇
  2013年   63篇
  2012年   35篇
  2011年   37篇
  2010年   39篇
  2009年   63篇
  2008年   39篇
  2007年   53篇
  2006年   33篇
  2005年   33篇
  2004年   24篇
  2003年   21篇
  2002年   25篇
  2001年   16篇
  2000年   15篇
  1999年   19篇
  1998年   78篇
  1997年   53篇
  1996年   64篇
  1995年   44篇
  1994年   49篇
  1993年   44篇
  1992年   10篇
  1991年   6篇
  1990年   11篇
  1989年   41篇
  1988年   27篇
  1987年   25篇
  1986年   20篇
  1985年   14篇
  1984年   17篇
  1983年   15篇
  1982年   14篇
  1981年   20篇
  1980年   13篇
  1979年   9篇
  1978年   10篇
  1977年   18篇
  1976年   8篇
  1975年   12篇
  1973年   2篇
  1910年   1篇
排序方式: 共有1272条查询结果,搜索用时 15 毫秒
71.
Fructosamine and glycated haemoglobin were measured simultaneously in 147 children with diabetes. If glycated haemoglobin is considered as the 'gold standard' for long term glycaemic control, then fructosamine is a poor indicator of actual glycated haemoglobin values, with wide 95% confidence (fiducial) limits. This shows that it is impossible to accurately predict glycated haemoglobin concentrations and therefore, by implication, longer term glycaemic control, from measurements of fructosamine. As the major studies on the prevention of microvascular complications in diabetes have used glycated haemoglobin levels to assess glycaemic control, it is suggested that this measurement should be used in all children with diabetes in preference to the measurement of fructosamine.  相似文献   
72.
Abstract: Excessive distension of venous grafts due to arterial pressure enhances the convective water transport (filtration flow) through the vessel wall, and thus might affect the infiltration of macromolecules such as lipoproteins. In this paired experimental study, filtration velocities were measured at 100 mm Hg for canine jugular veins with or without external supports of expanded poly-tetrafluoroethylene (ePTFE) arterial prostheses. In addition, to assess the effect of filtration velocity on lipid infiltration or uptake, canine jugular veins were wrapped over half of their lengths with ePTFE arterial prostheses and perfused with dog serum containing 3H-cholesterol at a pressure of 100 mm Hg. At 100 mm Hg, the average filtration velocity of the wrapped jugular veins was 7.9 ± 1.3 ± 10-6 cm/s whereas the average filtration velocity of the unwrapped veins was 27.3 ± 2.7 ± 10-6 cm/s (p < 0.005). Moreover, the unwrapped veins had a significantly higher uptake rate of labeled cholesterol than the wrapped veins (10.9 ± 7.3 ± 10-4 cm/h and 5.0 ± 1.6 ± 10-4 cm/h, respectively, p < 0.005). In conclusion, under arterial pressure, veins experience excessive distention, which leads to significant increases in both filtration flow and cholesterol uptake. An external wrap or support of ePTFE material protects veins from excessive distension and thus may prevent atherosclerosis in venous grafts by reducing cholesterol uptake.  相似文献   
73.
74.
75.
76.
PURPOSE: To develop a spinal functional MRI (fMRI) method with three-dimensional coverage of a large extent of the spinal cord with minimal partial volume effects MATERIALS AND METHODS: fMRI data of the cervical spinal cord were obtained at 1.5 T with a single-shot fast spin-echo imaging method, from thin contiguous sagittal slices spanning the cord. Thermal stimulation was applied to the palm of the hand in a block pattern with 15 degrees C for stimulation and 32 degrees C during baseline periods. Prior to analysis, the image data at each time point were reformatted into three-dimensional volumes and resliced perfectly transverse to the spinal cord. Smoothing was applied only in the superior-inferior (S/I) direction across uniform tissue types. Active voxels were then identified by means of a correlation to a model paradigm. RESULTS: The resulting activity maps demonstrate activity primarily in ipsilateral sensory areas and in some motor areas, consistent with the spinal cord neuroanatomy. These data also demonstrate detail of the subsegmental organization of the spinal cord, as well as anatomical detail of the spinous processes and positions of nerve roots. CONCLUSION: The spinal fMRI method described enables large volume coverage of the spinal cord in three dimensions, with reliable and reproducible results.  相似文献   
77.
78.

Background

In 2002, the World Health Organization published a health system performance ranking for 191 member countries. The ranking was based on five indicators, with fixed weights common to all countries.

Methods

We investigate the feasibility and desirability of using mathematical programming techniques that allow weights to vary across countries to reflect their varying circumstances and objectives.

Results

By global distributional measures, scores and ranks are found to be not very sensitive to changes in weights, although differences can be large for individual countries.

Conclusions

Building the flexibility of variable weights into calculation of the performance index is a useful way to respond to the debates and criticisms appearing since publication of the ranking.  相似文献   
79.
Ventral hernia repair: a study of current practice   总被引:5,自引:5,他引:0  
Ventral wall hernias are common; despite this, there are no guidelines on the best surgical management. The aim of this study was to examine the types of repair in use for abdominal wall hernias in the West of Scotland over a 3-month period. Data were gathered on 120 patients. There were 60 incisional, 32 umbilical, and 28 epigastric hernias. The main indication for repair was pain (78%), while 12 patients (10%), presented acutely with incarceration or strangulation. The most common method of repair was sutured (55%), followed by mesh (29%) and Mayo repair (16%). There was no correlation between use of mesh and hernia size or whether repair was for a recurrent hernia. Surgical practice varies widely in the repair of ventral wall hernias. Clinical trials are required to establish the best method of repair for this common condition. Electronic Publication  相似文献   
80.
OBJECTIVE: To determine whether topical administration of a corticosteroid improves resolution of acute tympanostomy tube otorrhea when combined with topical antibiotic drops. STUDY DESIGN: Randomized, patient-masked, parallel-group, multicenter trial of topical otic ciprofloxacin/dexamethasone versus topical ciprofloxacin alone in 201 children aged 6 months to 12 years with acute otitis media with tympanostomy tubes (AOMT) of less than or equal to 3 weeks' duration and visible otorrhea. METHODS: Eligible patients were randomized to receive three drops of either ciprofloxacin 0.3%/dexamethasone 0.1% or ciprofloxacin 0.3% into the affected ear or ears twice daily for 7 days. Clinical signs and symptoms of AOMT were evaluated on days 1 (baseline), 3, 8 (end-of-therapy), and 14 (test-of-cure), and twice-daily assessments of otorrhea were recorded in patient diaries. RESULTS: The mean time to cessation of otorrhea in the microbiologically culture-positive patient population (n = 167) was significantly shorter with topical ciprofloxacin/dexamethasone than with ciprofloxacin alone (4.22 vs. 5.31 days; P =.004). This resulted in significantly better clinical responses on days 3 and 8 (P <.0001 and P =.0499, respectively). However, there were no significant differences between the two treatment groups in either the clinical response or the microbial eradication rate by day 14. CONCLUSIONS: Topical otic treatment with ciprofloxacin/dexamethasone is superior to treatment with ciprofloxacin alone and results in a faster clinical resolution in children with AOMT. The contribution of the corticosteroid in achieving a 20% reduction (1.1 day) in time to cessation of otorrhea is clinically meaningful and represents an important advance over single-agent antibiotic therapy.  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