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   1133篇
  免费   67篇
  国内免费   15篇
耳鼻咽喉   3篇
儿科学   9篇
妇产科学   8篇
基础医学   216篇
口腔科学   15篇
临床医学   89篇
内科学   150篇
皮肤病学   16篇
神经病学   89篇
特种医学   94篇
外国民族医学   1篇
外科学   60篇
综合类   142篇
预防医学   125篇
眼科学   19篇
药学   97篇
中国医学   22篇
肿瘤学   60篇
  2024年   1篇
  2023年   12篇
  2022年   15篇
  2021年   27篇
  2020年   17篇
  2019年   59篇
  2018年   65篇
  2017年   35篇
  2016年   28篇
  2015年   21篇
  2014年   82篇
  2013年   64篇
  2012年   48篇
  2011年   99篇
  2010年   64篇
  2009年   65篇
  2008年   102篇
  2007年   67篇
  2006年   68篇
  2005年   44篇
  2004年   31篇
  2003年   26篇
  2002年   22篇
  2001年   20篇
  2000年   7篇
  1999年   9篇
  1998年   9篇
  1997年   16篇
  1996年   13篇
  1995年   7篇
  1994年   4篇
  1993年   6篇
  1992年   11篇
  1991年   6篇
  1990年   8篇
  1989年   3篇
  1988年   3篇
  1987年   1篇
  1986年   3篇
  1985年   11篇
  1984年   2篇
  1983年   6篇
  1980年   4篇
  1979年   2篇
  1977年   1篇
  1975年   1篇
排序方式: 共有1215条查询结果,搜索用时 656 毫秒
1.
2.
CR、CT、MRI在骨肿瘤诊断中的临床价值   总被引:13,自引:6,他引:7  
[目的]评价计算机X线摄影(CR)、CT、磁共振成像(MRl)在骨肿瘤诊断中的临床价值。[方法]回顾分析55例经病理证实的影像学资料,其中55例均有CR平片,21例CT扫描,20例做了MRI检查。[结果]55例中51例CR片清晰显示骨质改变,40例CR片清晰显示病灶边界,20例CR片清晰显示骨膜反应,19例CR片清晰显示病灶内有大小不一钙化。21例行CT扫描病例均清晰显示骨质改变、病灶边界、病灶内有大小不一钙化,8例清晰显示骨膜反应。20例做了MRI检查病例均清晰显示病灶边界及软组织肿块,8例显示相应骨髓水肿。[结论]CR片仍为骨肿瘤的首选检查方法,CT较好显示了肿瘤的范围及细微结构,MRI对显示肿瘤的范围、软组织肿块及相应骨髓水肿有明显优势。三者相结合有助于骨肿瘤的诊断。  相似文献   
3.
目的:讨论IP板及暗盒的使用与维护。方法:通过对我科IP板的使用、维护及新旧IP板的对比分析,总结出一些维护方法及经验。结果:IP板及暗盒在运动中受损以至无法正常工作是其被淘汰的主要原因,加强对IP板及暗盒的日常维护,有利于减少对IP板及暗盒的损伤,延长其使用寿命,提高图像质量。结论:应用CR系统必须重视对IP板及暗盒的维护。  相似文献   
4.
5.
Digital mammography using storage phosphor CR is still in the investigational stage. It is the only digital mammography system that has been tested in preliminary clinical trials with promising early results. Further clinical studies are needed to assess the impact of the limited spatial resolution of storage phosphor technology on its application as a digital screening mammography system. Further studies also are needed to determine the optimum image processing parameters needed in digital mammography.  相似文献   
6.
CR、CT、MRI在脊柱结核诊断中的临床价值   总被引:3,自引:2,他引:1  
[目的]评价计算机X线摄影(CR)、计算机断层成像(CT)、磁共振成像(MRI)在脊柱结核诊断中的临床价值。[方法]回顾分析经病理证实的41例脊柱结核的影像学资料。41例做了CR,22例做了CT,31例均做了MRI。[结果]41例中38例CR片清晰显示骨质改变及椎间隙狭窄或消失,30例CR片可看到软组织阴影。22例CT均清晰显示了钙化,22例CT检查附件均未见明显异常,21例CT清晰显示椎体骨质改变,20例CT显示了软组织阴影。31例MRI均显示软组织均受累,附件均未见受累,其中29例椎间隙狭窄或消失。病变T1WI均以低信号为主,T2WI均以高信号为主。[结论]CR片仍为脊柱结核的基本检查方法,CT较好显示了结核的破坏范围及细微钙化,MRI对显示结核的侵犯范围、软组织异常及椎间盘异常有明显优势。三者相结合有助于脊柱结核的诊断。  相似文献   
7.
CR、DR的工作原理及选择应用   总被引:2,自引:0,他引:2  
数字化是当前医学影像技术发展的主流,合理地选择CR、DR符合医院的发展要求,对CR、DR的工作原理、配置构成及基本技术参数进行分析,对目前医疗单位的放射设备的选择采购有一定的参考意义。  相似文献   
8.
We investigated the effects of suppression of complement activation at C3 level and inhibition of C5a on acute synovitis in rats. Acute synovitis was induced in Wistar rats by intra-articular (i.a.) injection into one knee of 0.3 mg of MoAb 6D1 (anti-rat CD59 antibody). In the treatment groups, soluble CR1 (sCR1) or C5a receptor (C5aR) antagonist was administered intra-articularly or intravenously and effects on the course of the acute synovitis were monitored. Synovitis induced by 6D1 was characterized by joint swelling, thickening of synovial tissue, cellular infiltration and deposition of membrane attack complex (MAC) on the synovial surface. Neither inflammatory change nor MAC deposition was found in rats which received an i.a. injection of sCR1 to suppress complement activity in the joint. Intra-articular injection of sCR1 did not reduce plasma complement activity. Intravenous administration of sCR1 suppressed plasma complement activity but had no effect on the course of the arthritis and synovitis with MAC deposition was observed. Neither i.a. nor i.v. injection of C5aR antagonist had any suppressive effects on inflammatory change or MAC deposition in synovium. The data show that inflammatory change induced by 6D1 was mediated by local complement activation and was not accompanied by systemic complement activation. C5a generation was not responsible for the observed inflammation, suggesting that other complement activation products, possibly MAC, mediate the inflammatory change observed in this model of acute synovitis in rats.  相似文献   
9.
Mouse monoclonal antibodies to the human C3b receptor   总被引:7,自引:0,他引:7  
Mouse monoclonal antibodies were raised against the human C3b receptor (CR1) molecule that had been purified from solubilized erythrocytes membranes. Four hybridomas were selected, cloned and expanded because their supernatants reacted strongly with insolubilized CR1 by ELISA and intensely stained B-dependent areas of the spleen and glomerular podocytes by indirect immunofluorescence. The four monoclonal antibodies, named J3D3, J8B10, J3B11 and J7C2, were IgG1 immunoglobulins. J3D3 immunoprecipitated two protein bands of apparent mol. wts 200,000 and 220,000 from 125I-surface-labeled human erythrocytes, which correspond to the two major allotypic forms of CR1. By indirect immunofluorescence, monoclonal antibodies stained polymorphonuclear leucocytes (PMN), most peripheral blood B-cells and a small subset of peripheral blood T-cells. J3D3 bound to CR1 on erythrocytes, PMN and lymphocytes with an affinity of 1-3 X 10(9) M-1 and recognized 170-1330 antigenic CR1 sites with an average of 740 sites/erythrocyte in 100 healthy individuals, approx. 50,000 sites/PMN and 15,000 sites/lymphocyte. There was a bimodal distribution of CR1 numbers on erythrocyte in the normal population. The four monoclonal antibodies similarly inhibited CR1-mediated decay of preformed cell-bound alternative- and classical-pathway C3 convertase sites. Two antibodies, J3D3 and J3B11, inhibited C3b-dependent rosette formation with lymphocytes, although much less efficiently than F(ab')2 polyclonal anti-CR1 antibody. Differences that were observed in the relative capacity of the antibodies to inhibit some of the functions of CR1 and in their ability to compete for binding of 125I-J3D3 to CR1 on erythrocytes, suggested that they are directed against different epitopes on CR1. Monoclonal antibodies provide useful means to assess and analyze the biological and immunoregulatory functions of the C3b receptor.  相似文献   
10.
胃肠道癌患者血清中抗癌胚抗原(CEA)抗体的检测及意义   总被引:1,自引:0,他引:1  
目的:探讨循环中抗癌胚抗原(CEA)特异性抗体的情况,评价CEA及抗体的联合检测在胃肠道癌诊断中的作用。方法:用放免法检测血清中 CEA含量,用酶联免疫吸附法(ELISA)检测抗 CEA IgG抗体,用竞争抑制法检测抗体的特异性。结果:胃肠道癌患者血清 CEA含量升高者(≥15 ng/ml)为 30.9%(21/68),抗 CEA IgG抗体阳性者为35.3%(24/68),CFA及抗 CEA抗体的联合检测可使阳性率提高到54.3%(37/68);胃肠道良性疾病患者(多发性息肉、溃疡、胰腺炎等)血清CEA升高者为3.3%(1/30),抗 CEA IgG抗体阳性者为 3.3%(1/30);健康对照组血清 CEA升高者为 0,抗 CEA IgG抗体阳性者为 2.5%(1/40)。结论:胃肠道癌患者血清中抗癌胚抗原(CEA)抗体的检出率较高,这些抗体可作为胃肠道癌的一种肿瘤标志物。  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