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   6454篇
  免费   191篇
  国内免费   73篇
耳鼻咽喉   156篇
儿科学   171篇
妇产科学   41篇
基础医学   521篇
口腔科学   373篇
临床医学   445篇
内科学   198篇
皮肤病学   11篇
神经病学   729篇
特种医学   389篇
外科学   2085篇
综合类   704篇
预防医学   113篇
眼科学   398篇
药学   252篇
  1篇
中国医学   63篇
肿瘤学   68篇
  2024年   19篇
  2023年   123篇
  2022年   213篇
  2021年   253篇
  2020年   200篇
  2019年   178篇
  2018年   223篇
  2017年   215篇
  2016年   241篇
  2015年   200篇
  2014年   472篇
  2013年   439篇
  2012年   372篇
  2011年   374篇
  2010年   267篇
  2009年   320篇
  2008年   315篇
  2007年   304篇
  2006年   264篇
  2005年   184篇
  2004年   190篇
  2003年   183篇
  2002年   122篇
  2001年   121篇
  2000年   114篇
  1999年   97篇
  1998年   86篇
  1997年   75篇
  1996年   73篇
  1995年   64篇
  1994年   52篇
  1993年   36篇
  1992年   36篇
  1991年   36篇
  1990年   23篇
  1989年   22篇
  1988年   23篇
  1987年   20篇
  1986年   24篇
  1985年   35篇
  1984年   18篇
  1983年   14篇
  1982年   9篇
  1981年   8篇
  1980年   7篇
  1979年   12篇
  1978年   16篇
  1977年   8篇
  1976年   9篇
  1974年   4篇
排序方式: 共有6718条查询结果,搜索用时 15 毫秒
81.
82.
《The surgeon》2021,19(5):268-278
ObjectiveTo compare clinical and imaging findings between extreme lateral lumbar interbody fusion (XLIF) and posterior fusion (PF) via meta-analysis for the treatment of lumbar degenerative diseases.MethodsEnglish papers reporting clinical and imaging findings for the treatment of lumbar degenerative diseases with XLIF and PF published electronically in the PubMed, Embase, Cochrane Library, and Web of Science databases from January 2006 to August 2019 were retrieved. Two authors independently extracted data and evaluated the quality of the included literature. Meta-analysis of outcome measures was performed using Stata 14 and RevMan 5.3 software.ResultsThis meta-analysis included 744 patients from nine studies, two of which were prospective studies, while the others were retrospective studies. The quality of each study was determined to be high. The meta-analysis showed no significant differences in the operative time, length of hospital stay, clinical effectiveness, and improvement in postoperative global sagittal alignment between two approaches (P > 0.05). However, XLIF was significantly better than PF in reducing intraoperative blood loss and recovery of local sagittal alignment (P < 0.05). Moreover, the high incidence of postoperative complications were detected in XLIF group (P < 0.05).ConclusionsBoth surgical approaches have equally promising clinical effectiveness for the treatment of lumbar degenerative diseases. Although XLIF can reduce intraoperative blood loss and obtain better postoperative local sagittal alignment than PF, the high incidence of postoperative complications should prompt us to consider why XLIF procedure is still being offered to our patients and how we can reduce these complications. In addition, any conclusions should be taken with caution because of the mix of prospective and retrospective studies, and the high heterogeneity and bias.  相似文献   
83.
Summary An anatomic study was undertaken to establish whether positioning of the leg and surgical approaches for total hip replacement (THR) cause changes in the femoral v. which may contribute to the development of deep vein thrombosis (DVT). The patency of 32 femoral vv. of 18 cadavers was inspected at different levels during simulated THR. Before and after removal of the femoral head through a transgluteal or posterior approach, a wide-angle endoscope was inserted into the femoral v. via the external iliac v. Blood flow was simulated by proximal irrigation with saline through the popliteal v. After removal of the femoral head distinct changes were observed in both approaches. In the transgluteal approach the changes were dependent on the degree of adduction and the body build of the cadaver. Initially, an oval form was seen in a constricted lumen with an increasingly oblique oval deformation and a final facet-like closure, usually at about 5 to 7.5 cm below the inguinal ligament. In total adduction this stenosis occured regardless of build. Using a posterior approach, the necessary internal rotation caused a closure of the vein in 50% of cases. In combination with flexion and adduction there was stenosis in all cadavers regardless of body build. Our results indicate that the duration of the adducted position of the thigh during THR via a transgluteal approach should be minimised, as there is a reduction in blood flow with even minor degrees of adduction. In the posterior approach the stenosis occurs earlier, and is independent of the build of the cadaver.
Étude anatomique de la sténose de la veine fémorale au cours des arthroplasties totales de hanche
Résumé L'étude anatomique a été réalisée pour établir la relation entre les différentes positions du membre inférieur au cours des arthroplasties totales de hanche et la survenue d'une thrombose veineuse profonde. Cette étude a été réalisée sur 18 cadavres, dont 32 vv. fémorales ont pu être examinées à différents temps de l'arthroplastie totale de hanche, avant et après ablation de la tête fémorale, par voie trans-glutéale ou par voie postérieure. Un endoscope (grand angle) a été introduit dans la v. fémorale par la v. iliaque externe. Le flux sanguin a été simulé par irrigation antérograde avec du sérum salé à travers la v. poplitée. Après l'ablation de la tête fémorale, il a été noté des différences significatives entre la voie d'abord trans-glutéale et la voie d'abord postérieure pour ce qui concerne l'aspect de la lumière de la v. fémorale et le flux sanguin. En ce qui concerne la voie trans-glutéale, ces modifications dépendaient du degré d'adduction et de la corpulence du cadavre. L'aspect de la lumière de la v. fémorale était initialement ovale, puis évoluait progressivement vers la sténose complète qui se situait à peu près entre 5 et 7,5 cm audessous du ligament inguinal. En adduction complète de la cuisse, la sténose se produisait, quelle que soit la corpulence du cadavre. En ce qui concerne la voie d'abord postérieure, la rotation médiale, indispensable à l'accès pour la mise en place de l'élément prothétique fémoral, causait une sténose de la v. fémorale dans 50% des cas. En ce qui concerne la combinaison des mouvements d'adduction et de flexion de la hanche, elle était responsable d'une sténose de la v. fémorale dans tous les cas, et ceci quelle que soit la corpulence du cadavre. Nos résultats indiquent que le durée de la position d'adduction de la cuisse durant l'arthroplastie totale de hanche par voie transglutéale devrait être diminuée car la réduction du flux sanguin dans la v. fémorale survient, même pour des petits degrés d'adduction. Dans la voie d'abord postérieure, la sténose survient plus tôt, elle ne dépend pas de la corpulence du cadavre.
  相似文献   
84.
The flexibility of the scoliotic spine is an important biomechanical parameter to take into account in the planning of surgical instrumentation. The objective of the paper was to develop a method to characterisein vivo the mechanical properties of the scoliotic spine using a flexible multi-body model. Vertebrae were represented as rigid bodies, and intervertebral elements were defined at every level using a spherical joint and three torsion springs. The initial mechanical properties of motion segments were defined fromin vitro experimental data reported in the literature. They were adjusted using an optimisation algorithm to reduce the discrepancy between the simulated and the measured Ferguson angles in lateral bending of three spine segments (major or compensatory left thoracic, right thoracic and left lumbar scoliosis curves). The flexural rigidity of the spine segments was defined in three categories (flexible, nominal, rigid) according to the estimated mechanical factors (α). This approach was applied with ten scoliotic patients under-going spinal correction. Personalisation of the model resulted in an increase of the initial flexural rigidity for seven of the ten lumbar segments (1.38≤α≤10.0) and four of the ten right thoracic segments (1.74≤α≤5.18). The adjustment of the mechanical parameters based on the lateral bending tests improved the model's ability to predict the spine shape change described by the Ferguson angles by up to 50%. The largest differences after personalisation were for the left lumbar segments in left bending (40±30). Thein vivo identification of the mechanical properties of the scoliotic spine will improve the ability of biomechanical models adequately to predict the surgical correction, which should help clinicians in the planning of surgical instrumentation manoeuvres.  相似文献   
85.
A new method of posterior C1-2 arthrodesis, derived from the W. V. Cone and G. Bertrand, technique (Montreal, 1970) is described with two modifications: (1) the exact measurements of the ideal graft are determined preoperatively, using CT and a sterilized pasteboard horseshoe-shaped model; (2) in the sitting postion, single occipital block graft was cut out microsurgically, using the preoperative model. After decortication of the graft, posterior arches of C1 and 2, and microsurgical excision of the cartilage of the C1-2 lateral joints, the graft was imbedded into the entire C1-2 space, fixed, and tightened using a braid of nylacap yarn. A case report of rotatory luxation and associated atlantoaxial instability in a 10-year-old girl illustrates the excellent functional results of this technique.Presented at the XVII Annual Meeting of the International Society for Pediatric Neurosurgery, Bombay 1989  相似文献   
86.
目的:探讨后囊混浊性白内障超声乳化摘除术的临床效果。方法:采用前囊连续环形撕囊,超声乳化晶体核,后囊同样连续环形撕囊,人工晶体囊袋内植入。结果:54例眼中视力≥0.8者25眼,0.6-0.7者23眼,0.3-0.5者6眼。结论:本结果提示前后囊连续环形撕囊,呈同心圆,囊袋内植入人工晶体术,对治疗后囊混浊性白内障,效果良好,值得在临床推广。  相似文献   
87.
评价沈氏经椎弓根内固定装置的生物力学稳定性。方法采用5具新鲜尸体脊柱标本,制造L1损伤模型,测量并比较标本在完整状态,损伤状态、沈氏装置固定、沈氏装置疲劳及CD装置固定下的T12和L2之间的三维运动范围,并将沈装置与CD装置固定下的运动范围进行,经统计学处理,评价沈氏装置的稳定性。  相似文献   
88.
Objective. To observe the clinical outcomes of using a new imtnunentafion SOCON system in the treatment of degenerative spondylolisthesis. Methods. Retrospective clinical and roentgenograph review of 21 patients who suffered from degenerative spondylolisthesis with spinal stenosis treated by decompression, posterolateral intertransverse arthrodesis, and with transpedicle instrumentation of SOCON system. Results. Nineteen of 21 patients were completely recovery from their preoperative symptoms, 17 of 18 cases with grade one slippage reduced to normal spine alignment, 2 cases of grade two slippage fully reduced, and one case of grade two spondylolisthesis got 70% reduction. Post-operative satisfactory rate was 90.5%. Pain relief was 90.5%.Neither infection nor neurologic complication occurred in this series. Conclusion. Our short time follow-up and limited cases showed satisfactory preliminary result of surgical treatment of spondylolisthesis with SOCON instrumentation.  相似文献   
89.
This study presents a new technique for visceral anastomosis. The principle consists of connecting the two parts to be anastomosed around a reabsorbable stent which is transluminally introduced into a small-diameter viscus, where it is fixed. Advancing a larger tube along the axis of the machine, the larger, perforated viscus is inverted and pulled over the stent, and finally a rubber band pops off the machine endoluminally in order to fix the intestinal walls in seroserosal contact onto the stent. To evaluate this micro anastomosis, a biliary bypass (choledochojejunostomy and roux-en-y-loop) was performed in ten pigs. Nine of ten animals showed biliary bypass with good runoff in contrast radiography and completely reabsorbed stent after a 3-month follow-up. Weight gain, bilirubin, and alkaline phosphatase were normal. This technology demonstrates a safe and quick way to perform instrumental micro anastomosis without remnant foreign material.Presented as a poster at the annual meeting of the Society of American Gastrointestinal Endoscopic Surgeons (SAGES), Nashville, TN, USA, 18–19 April 1994  相似文献   
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