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   3603篇
  免费   381篇
  国内免费   196篇
耳鼻咽喉   20篇
儿科学   54篇
妇产科学   23篇
基础医学   579篇
口腔科学   32篇
临床医学   472篇
内科学   681篇
皮肤病学   72篇
神经病学   269篇
特种医学   116篇
外国民族医学   1篇
外科学   405篇
综合类   326篇
现状与发展   1篇
一般理论   1篇
预防医学   274篇
眼科学   99篇
药学   270篇
中国医学   132篇
肿瘤学   353篇
  2024年   8篇
  2023年   82篇
  2022年   168篇
  2021年   168篇
  2020年   130篇
  2019年   136篇
  2018年   133篇
  2017年   101篇
  2016年   109篇
  2015年   158篇
  2014年   182篇
  2013年   161篇
  2012年   243篇
  2011年   270篇
  2010年   158篇
  2009年   176篇
  2008年   223篇
  2007年   203篇
  2006年   218篇
  2005年   181篇
  2004年   115篇
  2003年   120篇
  2002年   102篇
  2001年   70篇
  2000年   53篇
  1999年   65篇
  1998年   58篇
  1997年   42篇
  1996年   43篇
  1995年   36篇
  1994年   22篇
  1993年   17篇
  1992年   40篇
  1991年   19篇
  1990年   28篇
  1989年   23篇
  1988年   19篇
  1987年   22篇
  1986年   14篇
  1985年   19篇
  1984年   8篇
  1983年   6篇
  1982年   3篇
  1981年   2篇
  1979年   2篇
  1978年   4篇
  1977年   3篇
  1976年   4篇
  1971年   2篇
  1966年   2篇
排序方式: 共有4180条查询结果,搜索用时 15 毫秒
11.
Some effects of urease administration on laboratory animals   总被引:2,自引:0,他引:2  
  相似文献   
12.
13.
采用反相高效液相色谱蒸发激光散射检测器测定三七中人参皂苷Rg1的含量。色谱柱为CLC-ODS(6.0mm×150mm),流动相为乙腈-水(3070),蒸发激光散射检测器。定量方法简单,准确。回收率为100.50%,RSD为1.82%。并用紫外分光光度法测定了三七中总皂苷的含量,结果和HPLC法基本一致,说明该方法定量准确,回收率为101.50%,RSD为1.44%。结论认为两方法均可以控制三七的质量。  相似文献   
14.
Residues energetically linked to the allosteric transition of thrombin from its anticoagulant slow form to the procoagulant fast form have been identified by site-directed mutagenesis. The energetics of recognition by the two forms of the enzyme were probed by using a synthetic chromogenic substrate, fibrinogen, and hirudin. The thrombin residues E39, W60d, E192, D221, and D222 are linked to the slow-->fast transition and are part of an "allosteric core" through which events originating at the Na+ binding loop propagate to other regions of the enzyme. The thrombin residues Y76, W96, W148, and R173 lie at the periphery of the allosteric core, affect recognition of fibrinogen and hirudin to the same extent in both forms, and are not linked to the slow-->fast transition.  相似文献   
15.
PURPOSE: Denileukin diftitox is a fusion protein combining diphtheria toxin and interleukin-2 (IL-2) that targets tumor cells expressing the IL-2 receptor. Its efficacy has been shown in CD25+ cutaneous T-cell lymphoma, but not in B-cell non-Hodgkin's lymphoma (NHL). A phase II study was performed to evaluate the efficacy and tolerability of denileukin diftitox for relapsed or refractory B-cell NHL. PATIENTS AND METHODS: Patients with relapsed or refractory B-cell NHL were eligible. Tumor CD25 expression was determined by immunohistochemistry or flow cytometry. Denileukin diftitox was administered intravenously at a dose of 18 microg/kg once daily for 5 days every 3 weeks, up to eight cycles. RESULTS: Of the 45 patients assessable for response, 32 (71%) were refractory to the last chemotherapy treatment, and all were previously treated with rituximab. Three complete responses (6.7%) and eight partial responses (17.8%) were observed, for an overall response rate of 24.5%. Nine patients (20%) had stable disease. Objective response rates were similar in CD25+ (22%) and CD25- histologies (29%), as were stable disease rates (22% and 18%, respectively). For responding patients, the median time to treatment failure was 7 months, with a median follow-up in survivors of 18 months (range, 9 to 28 months), and the projected progression-free survival at 20 months was 24% (95% CI, 0% to 60%). Most toxicities were low-grade and transient. CONCLUSION: Denileukin diftitox seems to be effective in relapsed or refractory, CD25+ and CD25- B-cell NHL and is well-tolerated at the dosage evaluated. Evaluation of denileukin diftitox in combination with other agents may be warranted.  相似文献   
16.
为探讨肺癌脊柱转移放射治疗的时间剂量分割方法及其疗效,将肺癌脊柱转移64例患者随机分为治疗组和对照组,治疗组每次3Gy,每周5次,共30Gy;对照组每次2Gy,每周5次,共50Gy;两组均使用6mVX线照射.分别比较疼痛缓解率、止痛起效时间、及脊髓压迫缓解率.结果显示治疗组和对照组的疼痛缓解率分别为87.5%和81.3%,无显著性差异(P>0.05);平均止痛起效时间分别为8±2.2天和15±3.2天,差异性显著(P<0.01);脊髓压迫缓解率分别为85.0%和81.8%,无显著性差异(P>0.05).结果表明放射治疗肺癌脊柱转移疗效好,起效快,建议使用30Gy/10f/2W的时间剂量分割模式.  相似文献   
17.
ObjectiveTo evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.MethodsThis prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.ResultsA total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.ConclusionsNPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids.  相似文献   
18.
19.
In this study, we aimed to evaluate the effect of Nobiletin (NOB) on the placenta of Sprague–Dawley (SD) rats that had undergone reduced uterine perfusion pressure (RUPP) surgery and to evaluate the safety of NOB intervention during pregnancy. The results showed that NOB alleviated placental hypoxia, attenuated placental cell apoptosis, and inhibited placental damage in RUPP rats. No side effect of NOB intervention during pregnancy was observed. BeWo cell lines with P53 knockdown were then constructed using lentiviral transfection, and the P53 signaling pathway was found to be essential for NOB to reduce hypoxia-induced apoptosis of the BeWo cell lines. In summary, NOB attenuated hypoxia-induced placental damage by regulating the P53 signaling pathway, and those findings may contribute some insights into the role of NOB in placental development and the prevention of placental-related diseases.  相似文献   
20.
Primary liver cancer, mainly comprising hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC), remains a major global health problem. Although ICC is clinically different from HCC, their molecular differences are still largely unclear. In this study, precision N‐glycoproteomic analysis was performed on both ICC and HCC tumors as well as paracancer tissues to investigate their aberrant site‐specific N‐glycosylation. By using our newly developed glycoproteomic methods and novel algorithm, termed ‘StrucGP’, a total of 486 N‐glycan structures attached on 1235 glycosites were identified from 894 glycoproteins in ICC and HCC tumors. Notably, glycans with uncommon LacdiNAc (GalNAcβ1‐4GlcNAc) structures were distinguished from their isomeric glycans. In addition to several bi‐antennary and/or bisecting glycans that were commonly elevated in ICC and HCC, a number of LacdiNAc‐containing, tri‐antennary, and core‐fucosylated glycans were uniquely increased in ICC. More interestingly, almost all LacdiNAc‐containing N‐glycopeptides were enhanced in ICC tumor but not in HCC tumor, and this phenomenon was further confirmed by lectin histochemistry and the high expression of β1‐4 GalNAc transferases in ICC at both mRNA and protein expression levels. The novel N‐glycan alterations uniquely detected in ICC provide a valuable resource for future studies regarding to the discovery of ICC diagnostic biomarkers, therapeutic targets, and mechanism investigations.  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