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   678篇
  免费   19篇
  国内免费   68篇
耳鼻咽喉   5篇
儿科学   30篇
妇产科学   10篇
基础医学   92篇
口腔科学   9篇
临床医学   91篇
内科学   127篇
皮肤病学   17篇
神经病学   34篇
特种医学   141篇
外科学   34篇
综合类   26篇
预防医学   37篇
眼科学   1篇
药学   75篇
肿瘤学   36篇
  2022年   7篇
  2021年   7篇
  2020年   8篇
  2018年   6篇
  2016年   7篇
  2015年   10篇
  2014年   11篇
  2013年   22篇
  2012年   24篇
  2011年   21篇
  2010年   40篇
  2009年   33篇
  2008年   24篇
  2007年   69篇
  2006年   20篇
  2005年   24篇
  2004年   13篇
  2003年   18篇
  2002年   8篇
  2001年   9篇
  2000年   16篇
  1999年   11篇
  1998年   23篇
  1997年   34篇
  1996年   25篇
  1995年   24篇
  1994年   22篇
  1993年   20篇
  1992年   11篇
  1991年   12篇
  1990年   14篇
  1989年   16篇
  1988年   21篇
  1987年   13篇
  1986年   11篇
  1985年   14篇
  1984年   7篇
  1983年   5篇
  1982年   10篇
  1981年   6篇
  1980年   10篇
  1979年   3篇
  1978年   7篇
  1977年   9篇
  1976年   7篇
  1975年   9篇
  1972年   6篇
  1971年   2篇
  1969年   2篇
  1966年   2篇
排序方式: 共有765条查询结果,搜索用时 62 毫秒
21.
22.

Background  

There is currently an unprecedented expressed need and demand for estimates of maternal mortality in developing countries. This has been stimulated in part by the creation of a Millennium Development Goal that will be judged partly on the basis of reductions in maternal mortality by 2015.  相似文献   
23.

Background

Uncomplicated chronic rachialgia is a highly prevalent complaint, and one for which therapeutic results are contradictory. The aim of the present study is to evaluate the effectiveness and safety of treatment with auriculopressure, in the primary healthcare sector, carried out by trained healthcare professionals via a 30-hour course.

Methods/Design

The design consists of a multi-centre randomized controlled trial, with placebo, with two parallel groups, and including an economic evaluation. Patients with chronic uncomplicated rachialgia, whose GP is considering referral for auriculopressure sensory stimulation, are eligible for inclusion. Sampling will be by consecutive selection, and randomised allocation to one of the two study arms will be determined using a centralised method, following a 1:1 plan (true auriculopressure; placebo auriculopressure). The implants (true and placebo) will be replaced once weekly, and the treatment will have a duration of 8 weeks. The primary outcome measure will be the change in pain intensity, measured on a visual analogue scale (VAS) of 100 mm, at 9 weeks after beginning the treatment. A follow up study will be performed at 6 months after beginning treatment. An assessment will also be made of the changes measured in the Spanish version of the McGill Pain Questionnaire, of the changes in the Lattinen test, and of the changes in quality of life (SF-12). Also planned is an analysis of cost-effectiveness and also, if necessary, a cost-benefit analysis.

Discussion

This study will contribute to developing evidence on the use of auriculotherapy using Semen vaccariae [wang bu liu xing] for the treatment of uncomplicated chronic rachialgia.

Trial registration

Current Controlled Trials ISRCTN01897462.  相似文献   
24.
Objective: Physical inactivity is associated with elevated inflammatory markers, but little is known about the time trajectories of reduced physical activity and inflammatory markers. Changes in inflammatory markers in response to withholding regular aerobic exercise were prospectively examined and correlated with increased negative mood symptoms and fatigue that accompany exercise withdrawal. Methods: Participants with regular exercise habits (N = 40, mean age of 31.3 ± 7.5 years, 55% women) were randomized to aerobic exercise withdrawal or to continue regular exercise for 2 weeks. Protocol adherence was documented using ambulatory actigraphy. Inflammatory markers (interleukin-6, C-reactive protein, fibrinogen and soluble intercellular adhesion molecule-1) were assessed at weekly intervals. Negative mood was measured with the Profile of Mood States (POMS) and the Beck Depression Inventory (BDI), and fatigue with the Multidimensional Fatigue Inventory (MFI). Autonomic nervous system activity was examined using heart rate variability-based indices. Results: Changes in inflammatory markers did not differ between exercise withdrawal and control groups (multivariate p interaction = 0.25). Exercise withdrawal resulted in increased negative mood symptoms and fatigue from baseline to day 14 compared to controls (p ΔPOMS = 0.008, p ΔBDI = 0.002; p ΔMFI = 0.003), but these responses were not associated with changes in inflammatory markers (p-values >0.10). Inflammatory markers were also not correlated with autonomic nervous system dysregulation (p-values >0.10). Conclusion: Inflammatory markers were not increased following 2 weeks of exercise withdrawal. Negative mood symptoms and fatigue were not accounted for by changes in inflammatory markers. Compensatory feedback mechanisms may operate among healthy individuals to promote resilience from the effects of reduced exercise.  相似文献   
25.
Current methods using a single PET scan to detect voxel-level transient dopamine release—using F-test (significance) and cluster size thresholding—have limited detection sensitivity for clusters of release small in size and/or having low release levels. Specifically, simulations show that voxels with release near the peripheries of such clusters are often rejected—becoming false negatives and ultimately distorting the F-distribution of rejected voxels. We suggest a Monte Carlo method that incorporates these two observations into a cost function, allowing erroneously rejected voxels to be accepted under specified criteria. In simulations, the proposed method improves detection sensitivity by up to 50% while preserving the cluster size threshold, or up to 180% when optimizing for sensitivity. A further parametric-based voxelwise thresholding is then suggested to better estimate the release dynamics in detected clusters. We apply the Monte Carlo method to a pilot scan from a human gambling study, where additional parametrically unique clusters are detected as compared to the current best methods—results consistent with our simulations.  相似文献   
26.
27.
28.
Between 1978 and 1981, 74 women with nonpalpable breast cancer underwent surgery after localization guides were placed. In 72 patients, guides were introduced parallel to the chest wall; in two the needle was positioned anteroposteriorly under computed tomographic guidance. Fifty-six cases (76%) were infiltrating cancer; 13 (17%), intraductal cancers; two (3%), inflammatory; and three (4%), lobular carcinoma in situ. Surgery was not used to treat the latter five patients. In the remaining 69 women, 42 (61%) were treated by means of modified radical mastectomy; six (9%), total mastectomy; 12 (17%), local excision and radiation therapy; and seven (10%), local excision alone; exact therapy for two women (3%) was unknown. At a minimum follow-up of 5 years, none of the 67 women in whom the parallel approach was used had a local recurrence. The authors conclude that preoperative placement of guides parallel to the chest wall does not appear to increase the risk of local breast cancer recurrence.  相似文献   
29.
Impact of clinical history on fracture detection with radiography   总被引:3,自引:0,他引:3  
The effect of knowledge of localizing symptoms and signs in the detection of fractures was studied. Forty radiographs of the extremities were examined twice by seven radiologists; the sessions were separated by 4 months. In 26 cases, a subtle fracture was present; 14 cases were normal. In half of the cases at each session, the precise location of pain, tenderness, or swelling was provided. The observer was asked to determine if the case was normal or abnormal (provide the exact location of the fracture) and to indicate the degree of confidence in the diagnosis. Responses were converted to a numeric scale for analysis. Analysis of receiver operator characteristic parameters indicates that clues regarding location of trauma facilitate detection of fractures. The improvement is based largely on an increased true-positive rate without an increased false-positive rate, regardless of the decision criteria of the radiologist (overall willingness to "overread" or "underread"). This has direct clinical applicability and reinforces the plea of radiologists for precise clinical information.  相似文献   
30.

Introduction

Stomas often have to be sited in emergencies by trainees who may have had little training in this. Emergency stomas and stomas where the site has not been marked preoperatively by a stoma therapist are more prone to complications. These complications may severely affect a patient’s quality of life. Advice in the literature on how to best site stomas is conflicting. We compared two easy anatomical methods of siting stomas to sites chosen by a stoma therapist and looked at how this site was affected by the patients’ body mass index (BMI).

Methods

Patients undergoing elective colorectal surgery were seen either pre or postoperatively. Each patient’s BMI was recorded and the positions of three different potential stoma positions (site G: the gold standard, marked by a stoma therapist; site S: marked using a pair of scissors against the umbilicus; site H: halfway between the umbilicus and anterior superior iliac spine) were compared.

Results

The two fixed anatomical methods described (method S and method H) both gave poor results. The most common reason for poor siting was the proximity of a skin crease. There was a statistically significant correlation between the patient’s BMI and the laterality of the gold standard site.

Conclusions

The two simple anatomical methods described here do not provide a shortcut to effective siting. A more effective method may be calculating the laterality of the site using the patient’s BMI, and then moving up/down to avoid a skin crease and improve the patient’s view for changing the bag. This deserves further study.  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