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   1032篇
  免费   92篇
  国内免费   19篇
耳鼻咽喉   7篇
儿科学   35篇
妇产科学   5篇
基础医学   219篇
口腔科学   13篇
临床医学   132篇
内科学   56篇
皮肤病学   6篇
神经病学   118篇
特种医学   29篇
外科学   194篇
综合类   74篇
预防医学   147篇
眼科学   3篇
药学   41篇
中国医学   21篇
肿瘤学   43篇
  2023年   11篇
  2022年   39篇
  2021年   40篇
  2020年   32篇
  2019年   45篇
  2018年   33篇
  2017年   42篇
  2016年   37篇
  2015年   39篇
  2014年   43篇
  2013年   83篇
  2012年   49篇
  2011年   45篇
  2010年   48篇
  2009年   57篇
  2008年   51篇
  2007年   37篇
  2006年   38篇
  2005年   34篇
  2004年   30篇
  2003年   33篇
  2002年   29篇
  2001年   19篇
  2000年   18篇
  1999年   21篇
  1998年   13篇
  1997年   14篇
  1996年   15篇
  1995年   9篇
  1994年   14篇
  1993年   9篇
  1992年   7篇
  1991年   10篇
  1990年   12篇
  1989年   13篇
  1988年   9篇
  1987年   7篇
  1986年   6篇
  1985年   10篇
  1984年   10篇
  1983年   3篇
  1982年   9篇
  1981年   7篇
  1980年   3篇
  1979年   2篇
  1978年   4篇
  1977年   2篇
  1973年   1篇
  1969年   1篇
排序方式: 共有1143条查询结果,搜索用时 15 毫秒
1.
2.
目的 评价NITI悬臂梁在矫正舌倾下颌磨牙中的临床效果。方法 选择16例单侧下颌第二磨牙舌倾的病例为研究对象,带垫铸造支架连接双侧下颌后牙,提供颌内支抗、解除咬合锁结,0.018英寸×0.025英寸或0.019英寸×0.025英寸NITI悬臂梁提供颊向旋转力矩和压低力。采用Graphpad Prism 6.0 软件对治疗前、后所测数据进行配对 t 检验。结果 所有患牙均获得直立,牙轴变化24°±1.2°(P<0.01),近中舌尖到正中矢状面垂直距离变化(3±0.8) mm(P<0.05),牙周状况良好,咬合关系稳定。结论 铸造支架联合NITI 悬臂梁可提供有效力学机制,矫正舌倾下颌磨牙。  相似文献   
3.
The author describes his surgical approach to the problems of the aging upper arm and elbow region. Surgery at an appropriate age can prevent the progressive wrinkling of the elbow which is further aggravated by aging of the upper arm. The author's operation is aimed at correcting both portions of the arm anatomy at the same time.  相似文献   
4.
目的 评估镍钛记忆合金锁骨钩环抱器治疗新鲜重度肩锁关节脱位的临床疗效。方法 选择16例新鲜重度肩锁关节脱位患者,其中3例合并锁骨远端骨折,应用镍钛记忆合金锁骨钩环抱器治疗并进行临床疗效观察。随访6~12个月,平均7.6个月。结果 所有患者肩关节肌肉无萎缩,外观正常,肩关节活动范围正常,x线片示无再脱位征象。采用Karlsson术后疗效分级:A级15例,B级1例。结论 镍钛记忆合金锁骨钩环抱器治疗新鲜重度肩锁关节脱位创伤小,简便易行,疗效好,对合并锁骨远端骨折病人更具有独特优点,具有临床推广应用价值。  相似文献   
5.
The effects of haloperidol on motor and functioning and cognitive functioning were studied in young (3-5 months old) and aged (20-22 months old) male mice by examining haloperidol-induced catalepsy and haloperidol-induced decrements in performance on a radial arm maze. The aged mice were much more sensitive to these adverse effects of haloperidol than were the young mice. Studies of the distribution of radioactivity from [3H]haloperidol to the brain indicated that the differences in sensitivity to this drug were not due to pharmacokinetic differences. The results demonstrate that mice are suitable for studies of aging-induced changes in the behavioral effects of neuroleptic agents.  相似文献   
6.
The activity of single neurons in the superior colliculus was recorded while a rhesus monkey made arm movements to visual targets located on a screen in front of him. It was found that the activity of a subpopulation of cells was clearly related to these arm movements. The neurons began to discharge either with the onset of the movement, during the movement period, or well before the onset of electromyogram (EMG) activity and movement, and could be active for the entire duration of EMG activity. While the discharge pattern of some of these'reach'neurons was not different for movements to different target positions, other cells showed graded changes in activity depending on the direction of movement. The peak discharge rate could rise to > 100 impulses/s. Some units received somatosensory input; other reach cells exhibited a visual response and/or presaccadic activity. It is likely that the primate superior colliculus is not only involved in the initiation and control of orientating movements of the eyes but also in reaching movements of the arms.  相似文献   
7.
火器伤后胸心异物存留   总被引:8,自引:0,他引:8  
目的:探讨火器伤后胸心异物存留摘除的指征、时机、方法及结果。方法:回顾性分析了39例火器伤后胸心异物存留摘除者的一般资料、临床表现、不同处理方法的选择及效果。结果:19例患者早期因凝固性血胸及肺持续漏气伴异物存留或异物存留伴胸腔及心包腔化脓性感染,在开胸清创时做了异物摘除;另20例患者为胸伤伤情恢复后单纯异物存留,因异物位于肺门、心脏及大血管旁或远期并发症等,而后期开胸异物摘除。结论:火器性胸部穿透伤后,因异物本身或其他原因所致早期并发症者,应在开胸清创的同时摘除异物;胸伤伤情恢复而单纯胸心异物存留,应选择性摘除或因并发远期并发症而摘除。  相似文献   
8.
Reconstruction of skin defects of the distal third of the leg and foot is often a difficult task. Shape, resistance to shearing stresses in the weight-bearing surface and sensibility are the main features that have to be restored. For coverage of this region, the authors have used, in selected patients, the lateral arm flap (LAF) since 1994. This flap is thin, easy to dissect and has the possibility to be innervated through the posterior cutaneous nerve of the arm. Fourteen cases are presented. The drawbacks of this flap are the loss of sensibility in the forearm (partially transient) and the scar on the arm, which can be rather unsightly in young ladies and when big flaps are harvested skin graft is needed.  相似文献   
9.
This study examined the variability in movement end points in a task in which human subjects reached to targets in different locations on a horizontal surface. The primary purpose was to determine whether patterns in the variable errors would reveal the nature and origin of the coordinate system in which the movements were planned. Six subjects moved a hand-held cursor on a digitizing tablet. Target and cursor positions were displayed on a computer screen, and vision of the hand and arm was blocked. The screen cursor was blanked during movement to prevent visual corrections. The paths of the movements were straight and thus directions were largely specified at the onset of movement. The velocity profiles were bell-shaped, and peak velocities and accelerations were scaled to target distance, implying that movement extent was also programmed in advance of the movement. The spatial distributions of movement end points were elliptical in shape. The major axes of these ellipses were systematically oriented in the direction of hand movement with respect to its initial position. This was true for both fast and slow movements, as well as for pointing movements involving rotations of the wrist joint. Using principal components analysis to compute the axes of these ellipses, we found that the eccentricity of the elliptical dispersions was uniformly greater for small than for large movements: variability along the axis of movement, representing extent variability, increased markedly but nonlinearly with distance. Variability perpendicular to the direction of movement, which results from directional errors, was generally smaller than extent variability, but it increased in proportion to the extent of the movement. Therefore, directional variability, in angular terms, was constant and independent of distance. Because the patterns of variability were similar for both slow and fast movements, as well as for movements involving different joints, we conclude that they result largely from errors in the planning process. We also argue that they cannot be simply explained as consequences of the inertial properties of the limb. Rather they provide evidence for an organizing mechanism that moves the limb along a straight path. We further conclude that reaching movements are planned in a hand-centered coordinate system, with direction and extent of hand movement as the planned parameters. Since the factors which influence directional variability are independent of those that influence extent errors, we propose that these two variables can be separately specified by the brain.  相似文献   
10.
Ultrastructural abnormalities of spermatozoa and respiratory cilia have been reported in a male patient with Kartagener's syndrome and infertility.

In this patient both respiratory cilia and sperm tails showed defects in radial spokes and dynein arms. Such defects are heretofore undescribed in the same subject with immotile cilia syndrome.

Absence of both inner and outer dynein arms and absence of the inner dynein arms only were detected in spermatozoa and in respiratory tract cilia, respectively. Moreover, total absence of axoneme was seen in several sperm tails from this patient.

The possibility that the features described are of genetic origin is discussed.  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