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   16610篇
  免费   1420篇
  国内免费   1265篇
耳鼻咽喉   170篇
儿科学   189篇
妇产科学   139篇
基础医学   2161篇
口腔科学   259篇
临床医学   2135篇
内科学   2624篇
皮肤病学   119篇
神经病学   1004篇
特种医学   598篇
外国民族医学   15篇
外科学   1664篇
综合类   2711篇
现状与发展   1篇
一般理论   2篇
预防医学   1213篇
眼科学   535篇
药学   1558篇
  22篇
中国医学   739篇
肿瘤学   1437篇
  2024年   44篇
  2023年   255篇
  2022年   595篇
  2021年   847篇
  2020年   614篇
  2019年   522篇
  2018年   560篇
  2017年   539篇
  2016年   488篇
  2015年   786篇
  2014年   853篇
  2013年   787篇
  2012年   1183篇
  2011年   1356篇
  2010年   805篇
  2009年   696篇
  2008年   959篇
  2007年   963篇
  2006年   881篇
  2005年   975篇
  2004年   577篇
  2003年   509篇
  2002年   447篇
  2001年   360篇
  2000年   424篇
  1999年   403篇
  1998年   277篇
  1997年   235篇
  1996年   177篇
  1995年   178篇
  1994年   156篇
  1993年   135篇
  1992年   124篇
  1991年   122篇
  1990年   89篇
  1989年   82篇
  1988年   66篇
  1987年   64篇
  1986年   51篇
  1985年   40篇
  1984年   15篇
  1983年   12篇
  1982年   9篇
  1981年   8篇
  1980年   3篇
  1979年   9篇
  1974年   2篇
  1973年   4篇
  1972年   2篇
  1965年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
BackgroudPatients experiencing acute trauma have limited time for their involvement in shared decision making, which may lead to decisional conflict. The purpose of this study was to evaluate whether providing audiovisual surgical information can reduce decisional conflict when deciding between surgical and nonsurgical treatment in patients with distal radius fractures (DRFs) and to evaluate factors that may affect decisional conflict.MethodsWe prospectively enrolled 50 consecutive patients who presented with acute DRFs and chose to undergo surgery, for which volar plate fixation was recommended. We randomized these patients into 2 groups. The test group was given a video clip of audiovisual surgical information in addition to regular information while the control group was only given regular information. The video clip consisted of the purpose, procedure, and effect of the surgery, precautions and complications after the operation, and other treatment options that could be performed if operation was not performed. At 2 weeks after the surgery, we evaluated patients'' decisional conflict using a decisional conflict scale (DCS). In addition, we evaluated factors that might affect decisional conflict, such as age, dominant hand, comorbidities, history of previous operations, perceived disability, and provision of the video clip.ResultsThe test group showed significantly lower DCS scores than the control group (19.6 vs. 32.1, p = 0.001). In multivariate analysis, younger age and provision of the video clip were associated with lower DCS scores.ConclusionsThis study has demonstrated that providing information through audiovisual media such as video clips could reduce decisional conflict in patients who chose to undergo plate fixation for DRFs. This study also suggests that older patients may need more careful doctor-patient communication as they have more decisional conflict than younger patients.  相似文献   
42.
43.
淋巴因子激活的NK细胞杀伤肿瘤细胞的免疫电镜观察   总被引:3,自引:0,他引:3  
龚伊红  郭晰 《中华病理学杂志》1994,23(1):17-19,T005
用胶体金标记的扫描与透射免疫电镜术观察CD16^+淋巴因子激活的杀伤细胞杀伤肺腺癌细胞系LTEPa2或人红白血病细胞K562的过程。发现CD16^+LAK细胞能伸出分支的指状突起较深地插入肿瘤细胞浆内,造成靶细胞表面大小深浅不等的隐窝,及陷窝内局部细胞膜损伤,在CD16^+LAK细胞这种指状突起基底部附近的浆内,有大量胞浆颗粒与囊泡聚集。靶细胞被攻击后常发生凋落型死亡。同时可见坏死型死亡。说明CD  相似文献   
44.
冷冻同种异体骨段移植修复股骨近段大块骨缺损   总被引:1,自引:0,他引:1  
为观察大块冷冻同种异体骨移植后免疫功能的改变及预后,对13例恶性骨肿瘤瘤段切除后的骨缺损10.8~19.4cm(平均为14.6cm),分别采用冻冷异体松质骨段移植的髋关节加压融合术(6例)和异体股骨近段半关节移植成形术(7例)修复.10例分别于术前4天及术后14和28天检测其空腹外周血各项免疫学指标,以及术后3、6、9、12、24、48个月进行99mSPECT骨扫描(5例)和X-线片检查(12例),以观察宿主的免疫反应和异体骨愈合情况.结果:①外周血T淋巴细胞亚群(OKT3+,OKT4+,OKT8+)及血清补体(C3,C4)和循环免疫复合物(CiC)手术前后比较无显著性差异(P>0.05).②99mTe SPECT骨扫描显示:术后3~6个月移植的异体骨两端及髓腔内同位素浓集明显低于正常,而异体骨两端所对应的自体骨端同位素浓集明显高于正常,此现象于植入后9个月开始减弱,可达数年.X线片显示:异体骨愈合率为92.3%(12/13),2例移植的异体松质骨段于术后4~6年完全成活替代.以上可见:①冻冷异体骨段移植后宿主的全身免疫机能改变不明显,其反应是以局部炎症为主的细胞免疫过程;②异体骨可做为修复大块骨缺损的良好材料.  相似文献   
45.
二尖瓣脱垂的外科治疗   总被引:1,自引:0,他引:1  
报道57例二尖瓣脱垂(MVP0不同术式的外科治疗效果。手术随机分为3组;传统的二尖瓣成形组,Gore-Tex线人工腱索替换组和瓣膜置换组。结果显示,Ⅱ组和Ⅲ组术后每搏二尖瓣返流量明显少于Ⅰ组。各组术后长期随访机能状况均明显改善。MVP的外科治疗应首选二尖瓣成形;而Gore-Tex线人工腱索替换和人造瓣环盛开有方法安全可靠,其效果优于传统的腱索成形,并可避免瓣膜置换术后长期抗凝的并发症。  相似文献   
46.
P53与ras癌基因产物对直肠癌的诊断价值   总被引:3,自引:0,他引:3  
目的提高直肠癌术前活检的诊断率。方法5年来手术治疗的168例直肠癌病人中,有20例(11.9%)第一次手术前活检不能明确诊断。对其中17例患者的活检组织石蜡标本(实验组)和10例正常肠粘膜活检标本(对照组)进行常规病理、P53与ras癌基因产物检测。结果实验组中P53与ras基因表达阳性率分别为71%与47%,阳性率均高于常规病理,有显著性差异。17例标本中,11例为不典型增生,5例仅有慢性炎症。不典型增生的P53与ras基因表达分别为11例和7例,而慢性炎症则全部为阴性。二者之间,两种基因表达阳性率均有显著差异。实验结果还显示P53与ras基因表达有较好的一致性。对照组的10例正常肠粘膜的活检标本P53与ras基因检测结果均阴性,与实验组比较,P53阳性率有显著差异。结论P53与ras基因表达检测,可以作为常规病理的补充,提高直肠良恶性病变的鉴别力。  相似文献   
47.
Adams LD  Gong W  Vechia SD  Hunter RG  Kuhar MJ 《Brain research》1999,848(1-2):137-140
CART was identified as a novel mRNA regulated by psychostimulant drugs. CART peptides appear to be neurotransmitters involved in a variety of functions such as feeding. The mouse gene has been characterized and localized to Chromosome 13. The processing of CART peptides is evident in Western blotting studies.  相似文献   
48.
Our previous studies have demonstrated that overexpression of recombinant human interleukin-1 receptor antagonist protein (IL-1ra) via gene transfer can reduce ischemic brain injury. However, the mechanism of action of IL-1ra in ischemia is unclear. Since interleukin-1 can up-regulate intercellular adhesion molecules in endothelium, the present study was designed to determine whether overexpression of the IL-1ra can reduce the expression of intercellular adhesion molecule-1 (ICAM-1) after ischemic injury. Normal saline or adenovirus vector (1x109 particles) encoding the human IL-1ra gene (Ad.RSVIL-1ra) or the Escherichia coli LacZ gene (Ad.RSVlacZ) was injected into the right lateral cerebral ventricle of adult CD-1 mice. After five days, permanent middle cerebral artery occlusion (MCAO) was achieved for 24 h using an intraluminal suture. Cerebral blood flow was monitored by transcranial laser Doppler flowmetry to verify the occlusion. ICAM-1 protein was quantified using Western blot analysis and localized using immunohistochemistry. After MCAO, surface blood flow in the ischemic hemisphere was decreased to 9-11% of the baseline. There were fewer ICAM-1 positive vessels in the ischemic cortex of the Ad.RSVIL-1ra transfected mice than in the Ad.RSVlacZ transfected and saline treated mice (138+/-19 vs. 249+/-25, 284+/-22, p<0.05). Western blot analysis shows that ICAM-1 protein decreased 50-60% in the Ad. RSVIL-1ra group compared to the other two groups. There were no significant differences in the numbers of positive vessels in the ischemic basal ganglia and contralateral hemisphere among the three groups. Our studies suggest that IL-1ra overexpression can down-regulate the expression of ICAM-1 in the ipsilateral cortex in ischemic mice. Interleukin-1 may play an important role in the activation of inflammatory reaction during focal cerebral ischemia by promoting leukocyte adhesion on the endothelium cells.  相似文献   
49.
目的观察和研究敏感期内、末不同时限单眼斜视(monocularstrabismus,MS)和单眼剥夺(monoculardeprivation,MD)幼猫视皮质、外侧膝状体的脑源性神经营养因子(brainderivedneurotrophicfactor,BDNF)的可塑性变化。从形态学、分子神经生物学角度探讨不同时限MS和MD幼猫视  相似文献   
50.
The effects of repeated hyperbaric exposures on inner ear function and morphology in guinea pigs were investigated with auditory electrophysiological testing, histopathological and electron microscopic techniques associated with enzyme histochemical method. The results showed that repeated hyperbaric exposures, though considered "safe," did cause damage to the cochlear system. Possible causes of the pathology include direct effects of repeated compression and decompression on the ear, and the possibility of inner ear decompression sickness and barotrauma cannot be excluded.  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