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   5752篇
  免费   494篇
  国内免费   353篇
耳鼻咽喉   31篇
儿科学   99篇
妇产科学   113篇
基础医学   719篇
口腔科学   129篇
临床医学   769篇
内科学   1021篇
皮肤病学   83篇
神经病学   321篇
特种医学   264篇
外科学   719篇
综合类   769篇
现状与发展   2篇
一般理论   1篇
预防医学   299篇
眼科学   134篇
药学   505篇
  1篇
中国医学   202篇
肿瘤学   418篇
  2024年   16篇
  2023年   83篇
  2022年   193篇
  2021年   234篇
  2020年   183篇
  2019年   158篇
  2018年   201篇
  2017年   165篇
  2016年   178篇
  2015年   227篇
  2014年   286篇
  2013年   257篇
  2012年   401篇
  2011年   454篇
  2010年   254篇
  2009年   236篇
  2008年   297篇
  2007年   316篇
  2006年   257篇
  2005年   275篇
  2004年   209篇
  2003年   186篇
  2002年   150篇
  2001年   144篇
  2000年   139篇
  1999年   158篇
  1998年   117篇
  1997年   102篇
  1996年   85篇
  1995年   84篇
  1994年   62篇
  1993年   51篇
  1992年   50篇
  1991年   44篇
  1990年   42篇
  1989年   41篇
  1988年   36篇
  1987年   30篇
  1986年   35篇
  1985年   25篇
  1984年   24篇
  1983年   12篇
  1982年   13篇
  1981年   13篇
  1980年   7篇
  1979年   16篇
  1977年   9篇
  1976年   10篇
  1970年   7篇
  1969年   6篇
排序方式: 共有6599条查询结果,搜索用时 15 毫秒
41.
良性前列腺增生细胞因子变化的研究   总被引:1,自引:0,他引:1  
目的 探讨与细胞增生有关的细胞因子与BPH发生的相关性。方法 人前列腺分对照组 (正常前列腺 )和实验组 (良性前列腺增生 )。常规组织学染色观察组织形态的变化 ,免疫组织化学方法观察bFGF ,VEGF和EGFR在BPH中的改变。结果 BPH的病理变化呈多类型化。BPH的组织中bFGF和VEGF在间质中明显增加 ;EGFR在腺上皮和间质细胞中都增加明显。结论 在BPH的组织异常增殖中 ,间质的增殖可能与bFGF和VEGF的分泌增多关系密切 ,而EGFR与间质和腺上皮的异常增殖均有关。  相似文献   
42.
BACKGROUND: Until recently, there has been no practical alternative to the use of calcineurin inhibitors (CIs) as primary immunosuppressants in lung transplantation (LTx) and heart transplantation (HTx). Sirolimus (SRL) is a novel powerful immunosuppressant without renal toxicity, a common post-transplant problem associated with CI therapy. METHODS: SRL was used in 20 LTx and 5 HTx recipients >90 days post-transplant, where serious renal impairment was limiting CI dosing. Patients started on 2 to 5 mg/day orally at a median of 1,185 days post-transplant. Dosage adjustments were made according to trough levels, toxicity and perceived efficacy. With SRL initiation, 48% ceased CI therapy and the remainder decreased their dose substantively. RESULTS: After 30 days, 4 of 5 dialyzed patients ceased dialysis and 15 of 20 patients with an elevated serum creatinine (Cr) (mean Cr 0.29 mmol/liter) improved their Cr. The direction of change in Cr at 30 days predicted longer term Cr. The starting Cr did not predict the 30-day or long-term value. There were two bouts of acute and one bout of chronic rejection. There were 35 infectious complications in 16 patients and 24 episodes of potential SRL-related toxicity in 17 patients. These events generally responded to dose reduction or temporary cessation and were level-related. Fifteen recipients presently remain on the drug. None of the 7 deaths could be directly related to toxicity. CONCLUSION: SRL is a useful alternative immunosuppressant, allowing significant CI withdrawal in transplant recipients with renal impairment. Whether the resulting improvement in Cr can be maintained in the long term probably depends on the balance between the extent of acute and chronic renal damage.  相似文献   
43.
心形吻合术治疗先天性巨结肠的远期效果   总被引:15,自引:0,他引:15  
Wang G  Weng Y  Wei M  Sun X 《中华外科杂志》2002,40(5):344-346
目的 总结心形吻合术治疗巨结肠的经验。方法 回顾11年来心形吻合术治疗巨结肠的疗效,技术操作及改进,并发症的发生率和防治。结果 193例手术患者得到随访者152例,早期术后并发症15例,其中尿潴留2例,肠炎10例,吻合口狭窄1例,肠梗阻2例。晚期并发症22例,其中肠梗阻2例,便秘5例,切口疝2例,肠炎6例,7例偶有污粪,无盆腔、腹腔伤口感染、肛门失禁和死亡。结论 心形吻合术能明显减少术后并发症,提高疗效。  相似文献   
44.
Cultured human skin fibroblasts were irradiated twice successively with the 1.5 J/cm2 of 532-nm and 1,064-nm lasers, respectively. The mRNA of procollagen, matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), heat-shock protein 70 (Hsp70), interleukin-6 (IL-6) and transforming growth factor beta (TGF-β) were analyzed at 24 and 48 h post-irradiation by using RT-PCR. Both lasers significantly increased the expression of type I and III procollagen, TIMP1, and TIMP2, but decreased MMP1 and MMP2 expression. The 1,064-nm laser initiated TGF-β expression while the 532-nm laser elicited the increase of Hsp70 and IL-6. The increase/decrease rates of procollagen, TIMPs and MMPs for the 1,064-nm laser were higher than that of the 532-nm laser. Thus, both lasers effectively accelerated collagen synthesis and inhibited collagen degradation. Collagen synthesis induced by the 1,064-nm laser might be partly due to the upregulation of TGF-β expression, while the increase of Hsp70 and IL-6 might be partly responsible for collagen synthesis stimulated by the 532-nm laser. With the parameters used in this study, the 1,064-nm infrared laser is more effective in promoting the beneficial molecular activities than the 532-nm visible laser.  相似文献   
45.
"分段切开,多重挂线术"治疗高位复杂性肛瘘临床研究   总被引:4,自引:0,他引:4  
目的:观察"分段切开,多重挂线术"治疗高位复杂性肛瘘的临床疗效。方法:将60例高位复杂性肛瘘随机分为治疗组40例,采用"分段切开,多重挂线术";对照组20例,采用传统切开挂线术进行对比观察。结果:显示治疗组与对照组显愈率分别为95%和90%,无明显差异(P>0.05),但两组间的术后疼痛程度、创口愈合时间、肛门功能情况存在显著差异(P<0.05)。结论:在治疗高位复杂性肛瘘时,"分段切开,多重挂线术"与传统切开挂线术相比,具有手术操作简单,对组织损伤小,痛苦小、疗程短、肛门功能保护好等优点,该术式的应用,使得高位复杂性肛瘘治疗更加安全、有效。  相似文献   
46.
目的研究TKA患者膝关节胫骨平台冠状位倾斜度与临床结果之间的关系。方法回顾性分析我科自2004年1月至2005年2月期间TKA的骨关节炎病例261例。按术后胫骨平台假体内外翻情况分为3组:A组(外翻组)、B组(中立组)和C组(内翻组)。结果 A、B、C三组间在患者性别比例、年龄、体重指数、止血带时间、术后引流量、术后住院时间方面无显著差异。术前膝关节畸形情况各组间无显著差异。各组间术前ROM及HSS评分无显著差异。在术后2周时的膝关节活动度方面,A组与B、C两组间均存在显著差异(P〈0.01),B组与C组间存在显著差异(P〈0.05)。术后2周时HSS评分,A组与B、C两组间均存在显著差异(P〈0.05),但B组与C组间无显著差异。术后2年HSS评分A、B、C三组间无显著差异。A组中有1例、B组中有2例,C组中有2例伤口脂肪液化;B组中有3例、C组中有1例术后出现患肢小腿肌间静脉血栓。结论 TKA术后冠状位倾斜度与术前因素、手术因素及手术并发症之间无显著相关性。TKA术后力线对近期临床结果可能有显著影响。通过进一步康复锻炼可弥补力线对长期临床结果的影响。  相似文献   
47.
OBJECTIVE: We investigated outcomes after surgical therapy in patients with active infective endocarditis (AIE) with regard to survival in relation to surgical urgency, valve position, number of valves implanted and abscess formation. We aimed to identify independent risk factors for early mortality. METHODS AND RESULTS: Two hundred and fifty-five patients received Shelhigh bioprostheses between February 2000 and March 2007. A total of 74.1% had native and 25.9% prosthetic AIE. Surgery was regarded as urgent in 57.3% and as an emergency procedure in 38.4%. There was a highly significant difference in survival rate between patients who were operated on urgently versus in an emergency (p<0.0001), between single and double valve replacement (p=0.0206) and between patients with and without abscess formation (p=0.0245). There were two cases of early reinfection (0.78%) and six of late reinfection (2.35%) leading to re-operation. CONCLUSIONS: The survival of patients differs significantly in dependence on their surgical urgency. Better outcome could have been achieved if patients had been referred earlier for surgery and operated upon before heart failure or septic shock developed. Long-term survival was better in patients without abscess formation. The low reinfection rate of Shelhigh bioprostheses in AIE is promising and the early and mid-term results achieved need to be verified in the long-term course.  相似文献   
48.
目的 建立实时荧光定量逆转录聚合酶链反应(FQ-RT-PCR)检测AMACR mRNA的方法学并检测其在前列腺癌(PCa)组织中的表达.方法 在AMACR基因的2、3外显子之间设计一对引物及MGB探针,将PCR扩增产物与pMD18-T载体连接,构建重组质粒作为定量检测的标准品,建立实时荧光定量RT-PCR方法,然后对32例PCa、60例良性前列腺增生(BPH)及34例其它肿瘤组织进行AMACR mRNA的定量检测.结果 重组质粒经PCR扩增及序列测定,表明克隆成功,该方法灵敏度高,线性范围为5~5×108copies/reaction.AMACR mRNA在PCa组织中表达量显著高于BPH组织(P<0.01)及其他类型肿瘤组(P<0.01).ROC曲线分析结果显示,曲线下面积(AUC-ROC)为0.890,AMACR mRNA诊断前列腺癌的敏感度和特异度分别为81.3%和86.7%.PCa组织中AMACR mRNA表达量及检测阳性率与不同临床分期和病理分级之间的差异尚不具有统计学意义(P值均>0.05).结论 实时荧光定量RT-PCR检测AMACR mRNA的方法具有敏感、特异、准确、重复性好等特点.AMACR mRNA在前列腺组织中的表达对PCa的诊断具有一定的临床应用价值.  相似文献   
49.

Background  

In idiopathic scoliosis patients, after anterior spinal fusion and instrumentation, the discs (interspace angle) between the lowest instrumented vertebra (LIV) and the next caudal vertebra became more wedged. We reviewed these patients and analyzed the changes of the angle.  相似文献   
50.
OBJECTIVE: Due to the shortage of donor hearts, the criteria for organ acceptability have been considerably extended and donor grafts with coronary atherosclerosis are among those offered. This study evaluated whether and to what degree pre-existing coronary atherosclerosis may be acceptable. METHODS: A total of 1253 consecutive HTx recipients were investigated retrospectively for donor-transmitted coronary atherosclerosis (DCAS). Donor-transmitted coronary atherosclerosis was defined as focal atherosclerosis with stenosis of at least 50%. Inclusion criteria were absence of pre-HTx angiogram but performance of angiogram or autopsy within 6 months after heart transplantation. Kaplan-Meier analysis and log-rank test were used. RESULTS: Eighty-five out of 1253 (6.8%) cases were excluded, since coronary evaluation was not performed within 6 months (n=45) or hearts had undergone pre-transplant angiography (n=40). In 1086 patients no donor-transmitted coronary atherosclerosis was found (NDCAS group) and in 82 patients (7%) donor-transmitted coronary atherosclerosis was diagnosed by angiography (n=49) or autopsy (n=33). Single-vessel donor-transmitted coronary atherosclerosis was found in 53/82 patients (DCAS1 group) and double- or triple-vessel donor-transmitted coronary atherosclerosis in 26/82 patients (DCAS2/3 group). Three of the 82 patients with donor-transmitted coronary atherosclerosis were excluded since the autopsy report was unclear regarding degree of atherosclerosis. Early after heart transplantation the 30-day mortality in the NDCAS and DCAS1 groups was 12.2% versus 13.2% whereas in the DCAS2/3 group it was 61.5%. Beyond the first year the annual decrease with and without donor-transmitted coronary atherosclerosis (single-vessel disease) is comparable. CONCLUSIONS: Donor screening without coronary angiogram overlooks significant atherosclerotic lesions in a considerable number of cases (7.0%). Therefore, angiographic donor screening should be performed. Donor grafts with single-vessel coronary atherosclerosis may be accepted as marginal hearts; however, in our opinion, revascularisation (CABG, PTCA) should be considered. Grafts with two- or even three-vessel coronary atherosclerosis seem to have a serious risk for early graft failure. Beyond the first year the outcome of healthy grafts and grafts with donor-transmitted coronary atherosclerosis seems to be comparable.  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