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   339篇
  免费   15篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   21篇
妇产科学   4篇
基础医学   28篇
口腔科学   7篇
临床医学   37篇
内科学   53篇
皮肤病学   7篇
神经病学   8篇
特种医学   126篇
外科学   11篇
综合类   12篇
预防医学   14篇
眼科学   4篇
药学   13篇
  1篇
肿瘤学   5篇
  2023年   2篇
  2021年   6篇
  2018年   2篇
  2016年   10篇
  2015年   14篇
  2014年   5篇
  2013年   7篇
  2012年   11篇
  2011年   8篇
  2010年   7篇
  2009年   8篇
  2008年   5篇
  2007年   2篇
  2006年   2篇
  2005年   4篇
  2003年   2篇
  2002年   2篇
  2001年   2篇
  1999年   4篇
  1998年   17篇
  1997年   22篇
  1996年   21篇
  1995年   19篇
  1994年   15篇
  1993年   13篇
  1992年   4篇
  1991年   4篇
  1990年   6篇
  1989年   12篇
  1988年   18篇
  1987年   14篇
  1986年   11篇
  1985年   12篇
  1984年   3篇
  1982年   2篇
  1981年   7篇
  1979年   2篇
  1978年   6篇
  1968年   2篇
  1967年   4篇
  1966年   2篇
  1964年   2篇
  1961年   2篇
  1959年   4篇
  1958年   4篇
  1957年   3篇
  1956年   4篇
  1955年   2篇
  1954年   3篇
  1953年   2篇
排序方式: 共有355条查询结果,搜索用时 15 毫秒
81.
82.

Objectives

The aim of the study was to compare the risks of death among HIV‐infected patients on highly active antiretroviral therapy (HAART) in two proximate, yet distinct neighbourhoods: a neighbourhood with a high concentration of gay men, and a neighbourhood with a high concentration of injecting drug users.

Methods

We compared the clinical and socioeconomic characteristics of HIV‐infected patients from the two neighbourhoods entering the British Columbia Centre for Excellence in HIV/AIDS Drug Treatment Program from 1 September 1997 to 30 November 2005, using contingency table statistics. Cox survival models and Kaplan–Meier methods were used to estimate the cumulative mortality rates. Results We found significant differences between patients from the two neighbourhoods for all socioeconomic variables. Patients in the neighbourhood with a high concentration of injecting drug users were more likely to be female, have a history of injecting drug use, have a less HIV‐experienced physician and be less adherent. Patients in the neighbourhood with a high concentration of gay men were more likely to have AIDS. Mortality was significantly higher for patients in the neighbourhood with a high concentration of injecting drug users [hazard ratio (HR) 3.01; 95% confidence interval (CI) 1.73, 5.24].

Conclusions

A threefold increase was observed in the risk of death among HIV‐infected individuals on HAART in the neighbourhood with a high concentration of injecting drug users relative to the neighbourhood with a high concentration of gay men. The implications of this study should be assessed in similar HIV/AIDS epicentres.  相似文献   
83.
The present paper discusses the diagnostic challenges we faced in a 60-year-old woman with a history of schizophrenia, presenting with left unilateral facial pain for the past three months. Based on the elaborate clinical examination and diagnostic nerve blocks, the patient was diagnosed with trigeminal neuralgia (TN) and non-surgical therapy commenced. Further investigations with magnetic resonance imaging (MRI) and ultrasound-guided fine needle aspiration cytology (FNAC) revealed the presence of an extracranial schwannoma involving a branch of the maxillary nerve. The patient was symptomatically relieved after surgical excision of the benign tumor under general anesthesia. Hence, we emphasize the need for special care and attention in psychiatric patients presenting with orofacial pain.  相似文献   
84.
We compared the times necessary to perform different endotracheal drug application techniques during CPR. In a simulated CPR situation with a mannequin 28 paramedics and seven emergency physicians performed different drug instillation techniques in a randomized manner: direct injection into the upper end of the endotracheal tube (group tube), via a suction catheter placed into the bronchial system (group suction catheter), via a flexible venous catheter placed into the bronchial system (group venous catheter), using an EDGAR tube (an endotracheal tube with an injection channel within the wall of the tube (group EDGAR). We measured the time necessary to prepare the drug solution and compared the time necessary to prepare and perform each instillation method and the time the ventilation was interrupted. Comparison between groups was performed by the Kruskal-Wallis test. It took significantly longer to perform the more complicated techniques using suction catheters (26; 18 54 s) and venous catheters (30; 22-50 s) compared to the other two groups (median; min-max) (p < 0.05). No differences concerning the application time were found between the group tube (7; 5 14 s) and group EDGAR (8; 5-13 s). The time of interruption of chest compression's and ventilation: group suction tube (11; 5-19 s) and group catheter (12; 6-18 s) was significant longer than in group tube (5; 2-9 s) (p < 0.05). In group EDGAR the connection ventilator-tube remained intact due to its concept of drug application. The use of special devices such as suction catheters or venous catheters for endotracheal instillation during CPR results in significantly longer preparation and instillation times with a longer interruption of the oxygen supply and chest compression's.  相似文献   
85.
Background/aimTo investigate the histopathological effects of reabsorbable polyethylene glycol hydrogel (RPGH, Coseal) on epidural fibrosis (EF) following laminectomy in rats.Materials and methodsA total of 24 rats were equally divided into three groups. In the first group, no treatment was applied after laminectomy (control group, Group 1). In the second group, hemostasis was achieved after laminectomy, and 2 mm absorbable gelatin sponge soaked in saline was placed over the epidural space and the wound was closed (Group 2). In the third group, hemostasis was achieved following laminectomy, and 0.5 mL RPGH (Coseal, Group 3) was squeezed over the dura mater, and the wound was closed. A histopathological examination was undertaken to evaluate arachnoidal invasion and EF.ResultsThe results of EF in the Group 2 and Group 3 were significantly lower compared to the Group 1 (p = 0.023 and p = 0.002, respectively). No statistically significant difference was found between the Group 2 and Group 3 in terms of EF (p = 0.957). There was also no statistically significant difference between the mean arachnoidal invasion of the three groups (p > 0.171). However, the rate of arachnoidal invasion was the lowest in the Group 3.ConclusionIntraoperative Coseal, a polyethylene glycol polymer, tends to reduce the risk of epidural fibrosis, although this is not statistically significant.  相似文献   
86.

Objective

To formulate a simple rapid procedure for bioreduction of silver nanoparticles using aqueous leaves extract of Moringa oleifera (M. oleifera).

Methods

10 mL of leaf extract was mixed to 90 mL of 1 mM aqueous of AgNO3 and was heated at 60 - 80 °C for 20 min. A change from brown to reddish color was observed. Characterization using UV-Vis spectrophotometry, Transmission Electron Microscopy (TEM) was performed.

Results

TEM showed the formation of silver nanoparticles with an average size of 57 nm.

Conclusions

M. oleifera demonstrates strong potential for synthesis of silver nanoparticles by rapid reduction of silver ions (Ag+ to Ag0). Biological methods are good competents for the chemical procedures, which are eco-friendly and convenient.  相似文献   
87.
88.
89.
90.
BACKGROUND: Hydroxyethyl starches (HES) are known to interfere with blood coagulation according to molecular weight, the degree of substitution and the C2/C6 ratio. A recently developed low molecular hydroxyethyl starch (HES 130/0.4) was designed to reduce the blood compromising potency. METHODS: In this study, effects of a 30% in vitro haemodilution with the new HES preparation (HES 130/0.4) in comparison to HES 200/0.5, HES 450/0.7 and sodium chloride solution were investigated using intrinsic and extrinsic activated thrombelastography (TEG) and plasmatic coagulation tests. RESULTS: Whereas plasmatic tests revealed no prolongation of coagulation by HES in comparison to sodium chloride, the TEG variables clotting time, clot formation time and maximal clot firmness showed a significant (P<0.05) inhibition by all the HES preparations. The inhibition was most pronounced in HES 450 (P<0.05 vs HES 130) while HES 130 did not show a statistically significant difference in extrinsic activated maximal clot firmness when compared to sodium chloride. CONCLUSION: These in vitro results demonstrate that hydroxythyl starches especially compromise clot polymerisation. The new preparation HES 130/0.4 seems to inhibit platelet function to a lesser extent than hydroxyethyl starch preparations with a higher molecular weight and degree of substitution.  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