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   45390篇
  免费   3344篇
  国内免费   135篇
耳鼻咽喉   592篇
儿科学   1140篇
妇产科学   565篇
基础医学   5665篇
口腔科学   475篇
临床医学   4760篇
内科学   9145篇
皮肤病学   481篇
神经病学   4472篇
特种医学   1777篇
外科学   8727篇
综合类   349篇
现状与发展   1篇
一般理论   56篇
预防医学   3758篇
眼科学   802篇
药学   2846篇
中国医学   34篇
肿瘤学   3224篇
  2024年   61篇
  2023年   479篇
  2022年   853篇
  2021年   2060篇
  2020年   1068篇
  2019年   1711篇
  2018年   2066篇
  2017年   1448篇
  2016年   1469篇
  2015年   1620篇
  2014年   2328篇
  2013年   2752篇
  2012年   4353篇
  2011年   4246篇
  2010年   2229篇
  2009年   1880篇
  2008年   2970篇
  2007年   3073篇
  2006年   2583篇
  2005年   2301篇
  2004年   2016篇
  2003年   1691篇
  2002年   1479篇
  2001年   169篇
  2000年   133篇
  1999年   170篇
  1998年   258篇
  1997年   201篇
  1996年   142篇
  1995年   122篇
  1994年   99篇
  1993年   75篇
  1992年   59篇
  1991年   44篇
  1990年   38篇
  1989年   39篇
  1988年   38篇
  1987年   43篇
  1986年   33篇
  1985年   38篇
  1984年   38篇
  1983年   34篇
  1982年   39篇
  1981年   27篇
  1980年   32篇
  1979年   15篇
  1978年   17篇
  1974年   19篇
  1973年   17篇
  1972年   14篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Red cell exchange (RCE) is a common procedure in adults with sickle cell disease (SCD). Implantable dual lumen Vortex (DLV) ports can be used for RCE in patients with poor peripheral venous access. We performed a retrospective cohort study of RCE procedures performed in adults with SCD. The main objective of the study was to compare the inlet speed, duration of procedures and rate of complications performed through DLV ports to those performed through temporary central venous and peripheral catheters. Twenty‐nine adults with SCD underwent a total of 318 RCE procedures. Twenty adults had DLV ports placed and 218 procedures were performed using DLV ports. Mean length of follow‐up after DLV port placement was 397 ± 263 days. Six DLV ports were removed due to infection and 1 for malfunction after a mean of 171 ± 120 days. Compared to temporary central venous and peripheral catheters, DLV port procedures had a greater rate of procedural complications, a longer duration, and a lower inlet speed (all P < 0.01). When accounting for the maximum allowable inlet speed to avoid citrate toxicity, 40% of DLV port procedures were greater than 10% below maximum speed, compared to 7 and 14% of procedures performed through temporary central venous and peripheral catheters (P < 0.0001). In conclusion, DLV ports can be used for RCE in adults with SCD, albeit with more procedural complications and longer duration. The smaller internal diameter and longer catheter of DLV ports compared to temporary central venous catheters likely accounts for the differences noted. J. Clin. Apheresis 30:353–358, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   
3.
We present a patient with both dynamic left ventricular outflow tract obstruction and valvular aortic stenosis. The aortic valve was calcified, and velocities and gradients measured by continuous‐wave Doppler met standard criteria for severe aortic stenosis. The increased subvalvular velocities invalidated assumptions of the simplified Bernoulli equation; correction using the longer form of the Bernoulli equation suggested a lower but still significant gradient. The complex shape of the subvalvular spectral Doppler envelope indicated supranormal systolic function and dynamic left ventricular outflow obstruction. Left heart catheterization with an end‐hole catheter was required to determine the subvalvular and valvular components of the obstruction.  相似文献   
4.
5.
Advancing nanomedicines from concept to clinic requires integration of new science with traditional pharmaceutical development. The medical and commercial success of nanomedicines is greatly facilitated when those charged with developing nanomedicines are cognizant of the unique opportunities and technical challenges that these products present. These individuals must also be knowledgeable about the processes of clinical and product development, including regulatory considerations, to maximize the odds for successful product registration. This article outlines these topics with a goal to accelerate the combination of academic innovation with collaborative industrial scientists who understand pharmaceutical development and regulatory approval requirements—only together can they realize the full potential of nanomedicines for patients.  相似文献   
6.
7.
Introduction: Recently, a new minimally invasive single bundle technique for anatomic ACL reconstruction has been described, called the ‘All-Inside graft-link technique’. One of the advantages of this procedure is the reduced morbidity at the donor site as the graft choice is the quadrupled semitendinosus, thus sparing the gracilis tendon. The aim of this study was to evaluate isokinetic flexion strength recovery in patients who underwent a gracilis sparing technique compared to those with a full-tibial tunnel technique using a doubled gracilis and semitendinosus tendons (DGST) graft.

Methods: Patients were divided into two groups: Group A (22 patients) who underwent ACL reconstruction performed with an All-Inside graft-link technique; Group B (22 patients) who underwent ACL reconstruction with an Out-In technique and DGST graft. At a mean follow-up of 13 months, quadriceps and hamstring isokinetic peak torque deficits were recorded.

Results: In group A, the mean side to side peak torque flexion difference between the operated and non-operated limbs was ?3% and the mean torque at 30° was ?7.5% at high angular velocity (180°/sec); the mean peak flexion torque was 7.2% and the mean torque at 30° was 3.1% at low angular velocity (60°/sec).

In group B, the mean side to side peak flexion torque was ?3.5% and the mean torque at 30° was ?7.6% at high angular velocity (180°/sec); the mean peak flexion torque was ?7.2% and the mean torque at 30° was ?11% at low angular velocity (60°/sec).

A statistically significant difference was found between the two groups at lower angular velocity both for the mean peak flexion torque and the mean torque at 30° (= 0.009), with better results in the study group.

Discussion/conclusion: Gracilis sparing technique is a minimally invasive technique for ACL reconstruction and yielded a significantly better flexion strength recovery at lower angular velocity compared to a full tibial tunnel technique with DGST for ACL reconstruction.  相似文献   

8.
9.
ABSTRACT

Purpose

New instrument-based techniques for anterior chamber (AC) cell counting can offer automation and objectivity above clinician assessment. This review aims to identify such instruments and its correlation with clinician estimates.  相似文献   
10.

Introduction

In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.

Methods

We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.

Results

A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.

Conclusion

The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department.  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