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   1687篇
  免费   157篇
  国内免费   38篇
耳鼻咽喉   17篇
儿科学   33篇
妇产科学   14篇
基础医学   291篇
口腔科学   71篇
临床医学   190篇
内科学   146篇
皮肤病学   117篇
神经病学   178篇
特种医学   86篇
外科学   335篇
综合类   161篇
预防医学   21篇
眼科学   75篇
药学   41篇
中国医学   16篇
肿瘤学   90篇
  2024年   5篇
  2023年   38篇
  2022年   69篇
  2021年   83篇
  2020年   94篇
  2019年   67篇
  2018年   70篇
  2017年   82篇
  2016年   69篇
  2015年   60篇
  2014年   107篇
  2013年   101篇
  2012年   98篇
  2011年   82篇
  2010年   76篇
  2009年   61篇
  2008年   68篇
  2007年   82篇
  2006年   80篇
  2005年   37篇
  2004年   41篇
  2003年   41篇
  2002年   27篇
  2001年   28篇
  2000年   22篇
  1999年   35篇
  1998年   28篇
  1997年   22篇
  1996年   15篇
  1995年   13篇
  1994年   18篇
  1993年   28篇
  1992年   20篇
  1991年   12篇
  1990年   10篇
  1989年   8篇
  1988年   11篇
  1987年   12篇
  1986年   11篇
  1985年   7篇
  1984年   13篇
  1983年   4篇
  1982年   7篇
  1981年   4篇
  1980年   4篇
  1979年   5篇
  1978年   3篇
  1977年   1篇
  1976年   2篇
  1971年   1篇
排序方式: 共有1882条查询结果,搜索用时 858 毫秒
1.
2.
S. G. Brearley  S. Varey  A. Krige 《Anaesthesia》2023,78(10):1249-1255
Adequate postoperative analgesia is a key element of enhanced recovery programmes. Thoracic epidural analgesia is associated with superior postoperative analgesia but can lead to complications. Rectus sheath catheter analgesia may provide an alternative. In a nested qualitative study (within a two-year randomised controlled trial) focussing on the acceptability, expectations and experiences of receiving the interventions, participants (n = 20) were interviewed 4 weeks post-intervention using a grounded theory approach. Constant comparative analysis, with patient and public involvement, enabled emerging findings to be pursued through subsequent data collection. We found no notable differences regarding postoperative acceptability or the experience of pain management. Pre-operatively, however, thoracic epidural analgesia was a source of anticipatory fear and anxiety. Both interventions resulted in some experienced adverse events (proportionately more with thoracic epidural analgesia). Participants had negative experiences of the insertion of thoracic epidural analgesia; others receiving the rectus sheath catheter lacked confidence in staff members' ability to manage the local anaesthetic infusion pump. The anticipation of the technique of thoracic epidural analgesia, and concerns about its impact on mobility, represented an additional, unpleasant experience for patients already managing an illness experience, anticipating a life-changing operation and dealing with concerns about the future. The anticipation of rectus sheath catheter analgesia was not associated with such anxieties. Patients' experiences start far earlier than the experience of the intervention itself through anticipatory anxieties and fears about receiving a technique and its potential implications. Complex pain packages can take on greater meaning than their actual efficacy in relieving postoperative pain. Future research into patient acceptability and experience should not focus solely on efficacy of pain relief but should include anticipatory fears, anxieties and experiences.  相似文献   
3.
This study deals with a series of operations to isolate the micro-cellulose from the palm tree spathe sheath by using a modified chemical method to take into account the low cost and the completion speed and its characterization using X-ray diffraction technique (XRD), infrared spectroscopy (FTIR) and scanning electron microscope coupled with element analyzer (SEM/EDX). The results showed that the extraction method succeeded in obtaining very pure microscopic fibers with a width of 2–10 μm with a crystallinity index equal to 79.21%, containing the two cellulose features Iβ and II, that, the conversion ratio of the first to the second was estimated at 32, 87%.  相似文献   
4.
Placement of tunnelled dialysis lines is effective using ultrasoundand fluoroscopic guidance [1] and has a higher success ratethan ‘blind’ insertion [2]. After the ultrasound guided access into a neck vein, wires andcatheters are guided in to a suitable position in the  相似文献   
5.
经皮冠状动脉腔内成形术(PTCA)是近30年来治疗冠心病的主要技术之一,其相应的护理技术在过去近10年里有着明显的改进。本文以穿刺股动脉途径为重点综述国外PTCA术后留置动脉鞘管的护理进展:动脉外鞘管拔除责任者、拔除时间、拔管后局部压迫方法等内容,旨在提升PTCA术后的护理质量。  相似文献   
6.
The central-peripheral transitional zones of rat dorsolateral vagal rootlets are highly complex. Peripheral nervous tissue extends centrally for up to several hundred micrometers deep to the brainstem surface along these rootlets. In some instances this peripheral nervous tissue lacks continuity with the peripheral nervous system (PNS) and so forms an island within the central nervous system (CNS). In conformity with the resulting complexity of the CNS-PNS interface, segments of vagal axons lying deep to the brainstem surface are myelinated by one or more intercalated Schwann cells, contained in peripheral tissue insertions or islands, at either end of which they traverse an astroglial barrier. Intercalated Schwann cells are thus isolated from contact or contiguity with the Schwann cells of the PNS generally. They are short, having a mean internodal length of around 60% of that of the most proximal Schwann cells of the PNS proper, which lie immediately distal to the CNS-PNS interface and which are termed transitional Schwann cells. The thickness of the myelin sheaths produced by intercalated Schwann cells is intermediate between that of transitional Schwann cells and that of oligodendrocytes myelinating vagal axons of the same calibre distribution. This is not due to limited blood supply or to insufficient numbers of intercalated Schwann cells, the density of which is greater than that of transitional Schwann cells. These factors are unlikely to restrict expression of their myelinogenic potential. Nevertheless, the regression data show that the setting of the myelin-axon relationship differs significantly between the two categories of Schwann cell. Thus, the myelinogenic response of Schwann cells to stimuli emanating from the same axons may differ between levels along one and the same nerve bundle. Mean myelin periodicity was found to differ between sheaths produced by intercalated and by transitional Schwann cells.  相似文献   
7.
Neurosarcoma is a rare tumour originating from the sheath of peripheral nerves. Facial lesions have been reported in about 20 patients. We describe the MRI appearances of neurosarcoma with histological correlation in three patients. The lesions lay in the submandibular region, the left parapharyngeal space and the right orbit. MRI showed a well-defined mass with mixed components. The lesions were moderately heterogeneous on T1-weighted images in two cases and on T2-weighted images in all cases. Gadolinium enhancement occurred in all cases to variable degrees. In two cases, small high signal foci were seen on T2-weighted sequences. MRI appearances of neurosarcoma are not specific. Received: 3 September 1996 Accepted: 26 November 1996  相似文献   
8.
目的 探索手指屈肌腱在近节指骨段不同范围损伤时对屈指肌腱功能的影响。方法 采用12只成人尸体手指。实验分为:第一阶段屈指肌腱完整,以后四个阶段依次沿近节指骨掌侧小线闭开小央1/4、1/2、3/4及全长。在掌指关节被动屈80°和掌指关节屈80°同时近侧指关节屈100°时,测量指浅屈肌腱(FDS)和指深屈肌腱(FDP)的滑动距离。根据肌腱力臂和滑动距离的关系,得出屈指肌腱在掌指关节处和近侧指间关节及肌腱在近节指骨段的弓弦畸形程度。结果 腱鞘中央1/4切开时,指屈肌腱的滑动距离、力臂均无显著变化;1/2切开后,单纯屈曲掌指关节时的FDS腱和掌指、近节指间关节屈曲时的FDS、HDP腱的滑动距离和力臂较腱鞘完整时显苫增大(P<0.05);切开3/4长度后,FDS、FDP腱滑动距离均有统计学意义变化,FDS、FDP腱力臂平均增加8~9%;全切开腱鞘,FDS、FDP腱滑动距离变化正统计学上有高度显著性(P<0.01),两腱力臂分别增加16%和15%。随腱鞘切开范围增大,FDS、FDP在近节指骨段的弓弦畸形程度也越来越大。结论 从肌腱的生物力学变化可见,近节指骨段腱鞘的小范围损伤如中间1/4以内损伤时,对肌腱功能影响小,可以不予修复;若损伤超过1/2长度,尤其对腱鞘全长损伤,应予以修复以恢复肌腱功能。  相似文献   
9.
Thedevelopmentinmicrosurgicaltechniqueshasgreatlyimprovednervefunctionalrecovery .However ,owingtotheinabilitytocoaptateandsuturethousandsofnervefiberstotheirfunctionallysimilarnervefibersandinaccuratesutureofthenervestumps ,regeneratednervefiberspartiallylosethechancetoselectivelyregrowintotheirtargetendoneurialtubes,1 4whichresultsinaninevitablemismatchofmotorandsensorynervefibers .Thus,thecontact guidance basedmicrosurgicalnerverepairhasfailedtoachieveconsistentsatisfactoryfunctionalrecover…  相似文献   
10.
目的探讨体内可降解生物材料人发角蛋白(HHK)植入急性冲击性损伤脊髓后,对神经再生过程中少突胶质细胞增殖分化效应的影响。方法采用改制Ⅱ型NYU装置,在建立大鼠急性冲击性脊髓损伤模型基础上,将经过特殊处理后能在体内降解的HHK植入大鼠脊髓损伤部位,对植入后1、4、12、26周损伤脊髓组织进行光学和电镜结构观察。结果第1周时,损伤部位可见少突胶质细胞散在分布于大量浸润的炎症细胞中;第4周时,通过Mallory's磷乌酸苏木素染色,显示HHK周边呈层包绕的增生少突胶质细胞;第12和26周主要为神经再生和髓鞘重建过程,重建中的少突胶质细胞髓鞘内出现较大的空腔,髓鞘层状分离,并形成大小不一的髓鞘小体,重建髓鞘周边可见新生的少突胶质细胞。结论在急性冲击性脊髓损伤后神经再生过程中,HHK对少突胶质细胞的增殖分化及髓鞘再生修复有积极作用,为进一步综合研究HHK对脊髓损伤修复的作用提供了实验依据。  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