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   30512篇
  免费   1939篇
  国内免费   81篇
耳鼻咽喉   292篇
儿科学   779篇
妇产科学   1084篇
基础医学   4343篇
口腔科学   682篇
临床医学   2790篇
内科学   5941篇
皮肤病学   603篇
神经病学   3256篇
特种医学   1307篇
外国民族医学   3篇
外科学   4402篇
综合类   301篇
一般理论   46篇
预防医学   2046篇
眼科学   581篇
药学   2119篇
中国医学   39篇
肿瘤学   1918篇
  2021年   342篇
  2020年   219篇
  2019年   337篇
  2018年   467篇
  2017年   350篇
  2016年   409篇
  2015年   499篇
  2014年   727篇
  2013年   1065篇
  2012年   1459篇
  2011年   1598篇
  2010年   838篇
  2009年   846篇
  2008年   1330篇
  2007年   1459篇
  2006年   1537篇
  2005年   1462篇
  2004年   1365篇
  2003年   1347篇
  2002年   1305篇
  2001年   847篇
  2000年   840篇
  1999年   661篇
  1998年   405篇
  1997年   361篇
  1996年   239篇
  1995年   245篇
  1994年   204篇
  1993年   236篇
  1992年   481篇
  1991年   440篇
  1990年   441篇
  1989年   411篇
  1988年   403篇
  1987年   394篇
  1986年   388篇
  1985年   374篇
  1984年   320篇
  1983年   276篇
  1982年   239篇
  1981年   262篇
  1980年   241篇
  1979年   322篇
  1978年   221篇
  1977年   219篇
  1976年   212篇
  1975年   275篇
  1974年   277篇
  1973年   246篇
  1972年   209篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
European Surgery - Treatment of pilonidal sinus disease (PSD) requires a tailored approach. A national guideline was published in 2014. The current status of surgical PSD therapy...  相似文献   
2.
3.
4.
5.
6.
7.

Background

One approach to boost influenza vaccination coverage has been to expand immunization authority. In 2012, the province of Ontario gave community pharmacists the authority to administer the influenza vaccine.

Objective

This study investigates the perspectives of Ontario pharmacy patrons, who had not recently received this vaccine from a pharmacist, regarding this pharmacist service.

Methods

A survey was administered in six Ontario community pharmacies to pharmacy patrons who had not received an influenza vaccination from a pharmacist during the previous year. The instrument included questions about influenza vaccination, and knowledge of and attitudes toward vaccines and pharmacist-administered immunization.

Results

A total of 541 pharmacy patrons completed the survey (53.9% response rate). About one-third (30.5%) of respondents were not aware that pharmacists could give the influenza vaccine, with younger individuals being less likely to be aware (OR 0.48, 95% CI 0.29–0.77, p?<?0.05) and less likely to receive the vaccine annually (OR 0.28, 95% CI 0.19–0.42, p?<?0.05). Leading reasons respondents gave as to why they did not receive their influenza vaccine from a pharmacist included not wanting or feeling they needed to be immunized (41.6%) and being used to receiving the vaccine from a physician (16.5%). Concerns about the experience and training of pharmacists and lack of privacy in a community pharmacy were uncommon.

Conclusion

Reduced awareness of the availability of pharmacist-provided influenza vaccine is still common. Pharmacists have a significant opportunity to address lack of awareness and vaccine hesitancy issues. They can promote this service to increase influenza vaccination rates among pharmacy patrons who do not utilize this professional service.  相似文献   
8.
Motion is a major confound in diffusion‐weighted imaging (DWI) in the body, and it is a common cause of image artefacts. The effects are particularly severe in cardiac applications, due to the nonrigid cyclical deformation of the myocardium. Spin echo‐based DWI commonly employs gradient moment‐nulling techniques to desensitise the acquisition to velocity and acceleration, ie, nulling gradient moments up to the 2nd order (M2‐nulled). However, current M2‐nulled DWI scans are limited to encode diffusion along a single direction at a time. We propose a method for designing b‐tensors of arbitrary shapes, including planar, spherical, prolate and oblate tensors, while nulling gradient moments up to the 2nd order and beyond. The design strategy comprises initialising the diffusion encoding gradients in two encoding blocks about the refocusing pulse, followed by appropriate scaling and rotation, which further enables nulling undesired effects of concomitant gradients. Proof‐of‐concept assessment of in vivo mean diffusivity (MD) was performed using linear and spherical tensor encoding (LTE and STE, respectively) in the hearts of five healthy volunteers. The results of the M2‐nulled STE showed that (a) the sequence was robust to cardiac motion, and (b) MD was higher than that acquired using standard M2‐nulled LTE, where diffusion‐weighting was applied in three orthogonal directions, which may be attributed to the presence of restricted diffusion and microscopic diffusion anisotropy. Provided adequate signal‐to‐noise ratio, STE could significantly shorten estimation of MD compared with the conventional LTE approach. Importantly, our theoretical analysis and the proposed gradient waveform design may be useful in microstructure imaging beyond diffusion tensor imaging where the effects of motion must be suppressed.  相似文献   
9.
Introduction

Visible light spectroscopy (VLS) represents a sensitive, non-invasive method to quantify tissue oxygen levels and detect hypoxemia. The aim of this study was to assess the microperfusion patterns of the gastric pouch during laparoscopic Roux-en-Y gastric bypass (LRYGB) using the VLS technique.

Methods

Twenty patients were enrolled. Tissue oxygenation (StO2%) measurements were performed at three different localizations of the gastric wall, prior and after the creation of the gastric pouch, and after the creation of the gastro-jejunostomy.

Results

Prior to the creation of the gastric pouch, the lowest StO2% levels were observed at the level of the distal esophagus with a median StO2% of 43 (IQR 40.8–49.5). After the creation of the gastric pouch and after the creation of the gastro-jejunostomy, the lowest StO2% levels were recorded at the level of the His angle with median values of 29% (IQR 20–38.5) and 34.5% (IQR 19–39), respectively. The highest mean StO2 reduction was recorded at the level of the His angle after the creation of the gastric pouch, and it was 18.3% (SD ± 18.1%, p < 0.001). A reduction of StO2% was recorded at all localizations after the formation of the gastro-jejunostomy compared to the beginning of the operation, but the mean differences of the StO2% levels were statistically significant only at the resection line of the pouch and at the His angle (p = 0.044 and p < 0.001, respectively).

Conclusion

Gastric pouch demonstrates reduction of StO2% during LRYGB. VLS is a useful technique to assess microperfusion patterns of the stomach during LRYGB.

Graphical abstract
  相似文献   
10.
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