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   2619篇
  免费   82篇
  国内免费   9篇
耳鼻咽喉   16篇
儿科学   50篇
妇产科学   29篇
基础医学   310篇
口腔科学   140篇
临床医学   205篇
内科学   562篇
皮肤病学   23篇
神经病学   214篇
特种医学   174篇
外科学   268篇
综合类   16篇
预防医学   276篇
眼科学   41篇
药学   211篇
中国医学   3篇
肿瘤学   172篇
  2023年   11篇
  2022年   24篇
  2021年   42篇
  2020年   25篇
  2019年   18篇
  2018年   35篇
  2017年   27篇
  2016年   41篇
  2015年   28篇
  2014年   61篇
  2013年   86篇
  2012年   138篇
  2011年   147篇
  2010年   78篇
  2009年   92篇
  2008年   142篇
  2007年   158篇
  2006年   144篇
  2005年   135篇
  2004年   129篇
  2003年   130篇
  2002年   128篇
  2001年   43篇
  2000年   56篇
  1999年   51篇
  1998年   35篇
  1997年   39篇
  1996年   25篇
  1995年   25篇
  1994年   20篇
  1993年   23篇
  1992年   30篇
  1991年   27篇
  1990年   32篇
  1989年   50篇
  1988年   22篇
  1987年   29篇
  1986年   28篇
  1985年   22篇
  1984年   21篇
  1982年   14篇
  1981年   20篇
  1980年   17篇
  1979年   12篇
  1978年   14篇
  1976年   21篇
  1975年   15篇
  1974年   15篇
  1970年   10篇
  1932年   10篇
排序方式: 共有2710条查询结果,搜索用时 0 毫秒
81.
Repetition of jumps in dance and sport training poses a potential injury risk; however, non‐contact landing injuries are more common in athletes than dancers. This study aimed to compare the lower limb stiffness characteristics of dancers and athletes during drop landings to investigate possible mechanisms of impact‐related injuries. Kinematics and kinetics were recorded as 39 elite modern and ballet dancers (19 men and 20 women) and 40 college‐level team sport athletes (20 men and 20 women) performed single‐legged drop landings from a 30‐cm platform. Vertical leg stiffness and joint stiffness of the hip, knee, and ankle were calculated using a spring‐mass model. Stiffness data, joint kinematics, and moments were compared with a group‐by‐sex 2‐way analysis of variance. Multiple linear regression was used to assess the relative contribution of hip and knee and ankle joint stiffness to variance in overall vertical leg stiffness for dancers and athletes. Dancers had lower leg (P < 0.001), knee joint (P = 0.034), and ankle joint stiffness (P = 0.043) than athletes. This was facilitated by lower knee joint moments (P = 0.012) and greater knee (P = 0.029) and ankle joint (P = 0.048) range of motion in dancers. Males had higher leg (P < 0.001) and ankle joint stiffness (P < 0.001) than females. This occurred through lower ankle range of motion (P < 0.001) and greater ankle moment (P = 0.022) compared to females. Male and female dancers demonstrated reduced lower limb stiffness compared to athletes, indicating a more pliable landing technique. Dance training techniques could potentially inform approaches to injury prevention in athletes.  相似文献   
82.
83.
84.
The deposition of the amyloid beta-protein (Abeta) is a hallmark of Alzheimer's disease (AD). One reason for Abeta-accumulation and deposition in the brain may be an altered drainage along perivascular channels. Extracellular fluid is drained from the brain towards the cervical lymph nodes via perivascular channels. The perivascular space around cerebral arteries is the morphological correlative of these drainage channels. Here, we show that Abeta is immunohistochemically detectable within the perivascular space of 25 months old wild-type and amyloid precursor protein (APP)-transgenic mice harboring the Swedish double mutation driven by a neuron specific promoter. Only small amounts of Abeta can be detected immunohistochemically in the perivascular space of wild-type mice. Cerebrovascular and parenchymal Abeta-deposits were absent. In APP-transgenic mice, large amounts of Abeta were found in the perivascular drainage channels accompanied with cerebrovascular and parenchymal Abeta-deposition. The apolipoprotein E (apoE) immunostaining within the perivascular channels did not vary between wild-type and APP-transgenic mice. Almost 100% of the area that represents the perivascular space was stained with an antibody directed against apoE. Here, Abeta co-localized with apoE indicating an involvement of apoE in the perivascular clearance of Abeta. Fibrillar congophilic amyloid was not seen in wild-type mice. In APP-transgenic animals, congophilic fibrillar amyloid material was seen in the wall of cerebral blood vessels but not in the perivascular space. In conclusion, our results suggest that non-fibrillar forms of Abeta are drained along perivascular channels and that apoE is presumably involved in this clearance mechanism. Overloading such a clearance mechanism in APP-transgenic mice appears to result in insufficient Abeta-clearance, increased Abeta-levels in the brain and the perivascular drainage channels, and finally in Abeta-deposition. In so doing, our results strengthen the hypothesis that an alteration of perivascular drainage supports Abeta-deposition and the development of AD.  相似文献   
85.
Sawatzky B, Denison I, Langrish S, Richardson S, Hiller K, Slobogean B. The Segway Personal Transporter as an alternative mobility device for people with disabilities: a pilot study.

Objectives

To determine the functional measures that best correlate with the skill levels of people with disabilities who operate a Segway Personal Transporter, and—using a qualitative analysis—to explore subjects’ experience with the Segway.

Design

A prospective study encompassing 3 training sessions with the Segway to correlate subjects’ functional ability (eg, cognition, balance, mobility, muscle strength) with their skill level on the device.

Setting

A provincial adult rehabilitation center.

Participants

Twenty-three subjects (age range, 19−65y) with a wide range of disabilities (eg, multiple sclerosis, spinal cord injury, amputation) who could walk at least 6m with or without assistance.

Interventions

Not applicable.

Main Outcome Measures

Segway Task Assessment, Berg Balance Scale, and Timed Up & Go test.

Results

No correlation was found because all participants successfully completed the final Segway Task Assessment, regardless of scores on functional assessments.

Conclusions

The Segway is a useful device for a broad range of populations with functional disabilities. Subjects found the Segway easy to use and were excited about its potential as an assistive device for use in their communities.  相似文献   
86.
A prospective study of the impact of training 41 hospice nurses in assessment skills was used to test hypotheses that blocking behaviours would be used more when patients disclosed feelings and used less when nurses perceived that they had satisfactory professional support Each nurse was asked to assess a patient's current problems before and after feedback training and 8 months later Audiotape recordings of these interviews were rated by trained raters They determined the frequency of nurses' responses which had the function of blocking patient disclosure and the emotional level of patient disclosure Before each patient assessment each nurse was interviewed and questionnaires administered to measure her perceptions of the support she received Blocking behaviours were most evident when patients disclosed their feelings (Kendalls r=0 36, P < 0 001) In interviews containing most patient disclosure of feeling, blocking was significantly less (r= - 0 24, P < 0 5) when the nurse felt that practical help would be available if needed and when the nurse felt that her direct supervisor was concerned about the nurse's own welfare (r= -0 37, P < 0 005)  相似文献   
87.

Objective

Based on the initial survey of the project “Strengthen parents for dealing with the alcohol consumption of their children” parental style was quantified. The survey addressed the following issues: 1. The parents information of the alcohol consumption of their adolescents. 2. Adequate rules when dealing with the alcohol consumption of their children. 3. Parent?s reactions to a potential intoxication of their children.

Method

2,793 parents of students in grades 8–10 were surveyed in Baden-Württemberg, Berlin, Saxony and Schleswig-Holstein. The questionnaires were passed back through the teachers. The questionnaires were collected by the teachers.

Results

The results show that parents feel well informed about alcohol related education of children. 71?% use the internet as an information source. Approx. 95?% of the parents have talked with their children about alcohol consumption, particularly adviced them of health damages and development of dependence. Those rules of behavior guaranteeing a safe way home are favored by parents. In response to rule violations the parents talk with their children first. The comparison with current youth surveys shows that parents underestimate their children?s drinking.

Conclusions

Alcohol and its consequences are a topic of conversation among parents and children. The parents need support to argue objectively and according to youth. The Internet should be used for drug prevention education activities.  相似文献   
88.
We report a case of a prenatally detected hemangioma of the umbilical cord as an early sign of diffuse neonatal hemangiomatosis (DNH). The newborn was diagnosed with multiple hemangiomas in the liver, intestines, skin, and brain. Prenatal ultrasound findings, neonatal appearance of the hemangiomas, and the associated complications are illustrated. Interdisciplinary investigations as well as operative and systemic treatment approaches proved to be challenging. This case illustrates how prenatal ultrasound with color Doppler facilitates the early diagnosis of DNH and can help through the early referral to specialized centers for appropriate treatment.  相似文献   
89.
90.
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