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   357453篇
  免费   33997篇
  国内免费   24710篇
耳鼻咽喉   3429篇
儿科学   3902篇
妇产科学   5284篇
基础医学   44467篇
口腔科学   6173篇
临床医学   48139篇
内科学   53012篇
皮肤病学   3635篇
神经病学   20242篇
特种医学   13955篇
外国民族医学   227篇
外科学   37013篇
综合类   56928篇
现状与发展   85篇
一般理论   26篇
预防医学   21546篇
眼科学   10518篇
药学   37044篇
  359篇
中国医学   19788篇
肿瘤学   30388篇
  2024年   346篇
  2023年   4857篇
  2022年   7795篇
  2021年   15681篇
  2020年   13340篇
  2019年   12032篇
  2018年   12701篇
  2017年   11168篇
  2016年   10716篇
  2015年   16331篇
  2014年   20230篇
  2013年   17892篇
  2012年   26411篇
  2011年   29643篇
  2010年   18782篇
  2009年   14489篇
  2008年   19703篇
  2007年   19690篇
  2006年   19488篇
  2005年   19103篇
  2004年   12446篇
  2003年   11629篇
  2002年   10021篇
  2001年   8611篇
  2000年   9108篇
  1999年   9741篇
  1998年   5787篇
  1997年   5852篇
  1996年   4545篇
  1995年   4289篇
  1994年   3483篇
  1993年   2253篇
  1992年   3051篇
  1991年   2584篇
  1990年   2254篇
  1989年   2005篇
  1988年   1668篇
  1987年   1412篇
  1986年   1187篇
  1985年   966篇
  1984年   562篇
  1983年   392篇
  1982年   266篇
  1981年   252篇
  1980年   201篇
  1979年   233篇
  1977年   97篇
  1974年   110篇
  1973年   96篇
  1972年   89篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
61.
ObjectiveTo evaluate the efficacy and safety of prompt phacoemulsification, intraocular lens implantation, visco-goniosynechialysis, combined with pseudo-pupilloplasty for refractory acute primary angle closure (APAC) with atonic dilated pupil and to describe a feasible method of pupilloplasty.MethodsA consecutive series of refractory APAC patients who had atonic dilated pupil and undergone prompt phacoemulsification combined with pseudo-pupilloplasty at our center were retrospectively analyzed. Pseudo-pupilloplasty referred to a method of pupilloplasty which included 4.5-mm capsulorhexis, postoperative opacification of anterior capsule residue, and ultimate pseudo-pupil formation. Preoperative and postoperative measurements included intraocular pressure (IOP), best corrected visual acuity (BCVA), and anterior chamber depth (ACD). Intraoperative and postoperative complications were documented. The process of pseudo-pupil formation was also observed.ResultsA total of 20 eyes of 19 APAC patients were followed up for 19.7 ± 9.8 months. IOP was lowered from preoperative 44.0 ± 9.8 mmHg to 15.5 ± 2.6 mmHg at final visit (t = 11.945, P < 0.001). ACD was deepened from preoperative 1.77 ± 0.21 mm to 3.40 ± 0.20 mm at final visit (t = –27.711, P < 0.001). Twelve of 20 eyes had residual angle synechiae, whereas only 3 eyes needed anti-glaucoma medications. No severe complication was observed. All eyes had pseudo-pupil gradually formed within 3 months, accompanied with the gradual improvement of BCVA from preoperative 1.18 ± 0.55 to 0.58 ± 0.22, 0.26 ± 0.09, 0.11 ± 0.09, and 0.11 ± 0.09 at postoperative day 1, month 1, month 3, and last visit.ConclusionsPrompt phacoemulsification-goniosynechialysis is effective and safe for refractory APAC with atonic dilated pupil. Pseudo-pupilloplasty is a feasible procedure for pupil reconstruction.  相似文献   
62.
63.
Cantharidin (CTD) is an effective antitumor agent. However, it exhibits significant hepatotoxicity, the mechanism of which remains unclear. In this study, biochemical and histopathological analyses complemented with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS)-based targeted metabolomic analysis of bile acids (BAs) were employed to investigate CTD-induced hepatotoxicity in rats. Sixteen male and female Sprague–Dawley rats were randomly divided into two groups: control and CTD (1.0 mg/kg) groups. Serum and liver samples were collected after 28 days of intervention. Biochemical, histopathological, and BA metabolomic analyses were performed for all samples. Further, the key biomarkers of CTD-induced hepatotoxicity were identified via multivariate and metabolic pathway analyses. In addition, metabolite–gene–enzyme network and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to identify the signaling pathways related to CTD-induced hepatotoxicity. The results revealed significantly increased levels of biochemical indices (alanine aminotransferase, aspartate aminotransferase, and total bile acid). Histopathological analysis revealed that the hepatocytes were damaged. Further, 20 endogenous BAs were quantitated via UHPLC-MS/MS, and multivariate and metabolic pathway analyses of BAs revealed that hyocholic acid, cholic acid, and chenodeoxycholic acid were the key biomarkers of CTD-induced hepatotoxicity. Meanwhile, primary and secondary BA biosynthesis and taurine and hypotaurine metabolism were found to be associated with the mechanism by which CTD induced hepatotoxicity in rats. This study provides useful insights for research on the mechanism of CTD-induced hepatotoxicity.  相似文献   
64.
65.
目的分析超长住院患者分布及影响因素,探讨减少超长住院日的措施。方法从江苏省某三甲医院病案管理系统中调取2020年1月1日-2020年12月31日134016例出院患者的住院病案首页资料,对住院时间≥30天的1401例超长住院患者的分布特征进行统计描述,采用Logistic回归模型分析超长住院日的影响因素。结果2020年全院平均住院日为7.13天,其中超长住院患者平均住院日为41.85天。超长住院患者以60岁以上年龄组最多(39.61%);出院科室主要分布在血液科(42.18%)、普通外科(11.85%)、骨科(7.49%)等;疾病类别主要为肿瘤(47.32%)、影响健康状态和与保健机构接触的因素(10.56%)、循环系统疾病(7.07%)等;多因素Logistic回归结果显示,男性(OR=1.188)、离院方式为非医嘱离院或其他(OR=2.046)和死亡病例(OR=3.362)是超长住院的危险因素。结论控制超长住院日对平均住院日影响显著,医院应加强重点人群、重点科室和重点病种管理提高诊疗管理水平,缩短平均住院日。  相似文献   
66.
目的:比较急性缺血性卒中患者卒中后认知障碍的发生与软脑膜侧支循环的代偿程度及是否接受静脉溶栓治疗的相关性。方法:前瞻性收集2019年1月至2021年3月在石河子市人民医院住院的急性前循环脑梗死患者161例,获取患者入院时人口学资料,包括是否溶栓、性别、合并症等;通过蒙特利尔认知评估量表(Montreal cognitive assessment,MoCA)评分、简易精神状态检查量表(mini mental state examination,MMSE)评分评估患者认知功能;入院时美国国立卫生院卒中量表(National Institute of Health Stroke Scale,NIHSS)评分获取患者神经功能缺损症状;通过Blessed行为量表(Blessed behavior scale,BBS)评分评估患者的日常生活能力;通过区域软脑膜评分(regional leptomeningeal collateral score,rLMC)获取患者软脑膜侧支循环;根据卒中后6个月是否合并认知障碍分为认知障碍组和非认知障碍组,采用logistic多因素回归方法进行统计比较,分析2组患...  相似文献   
67.
重楼是我国传统的名贵中药,七叶一枝花为历版《中国药典》收载的重楼药材两个基原植物之一,具有清热解毒、消肿止痛、活血化瘀等功效,其主要活性成分为甾体皂苷类物质。由于重楼市场需求量剧增和七叶一枝花成药时间较长,导致大量依靠人工种植。然而,人工种植过程中产地、采收年限和采收月份都会影响七叶一枝花的甾体皂苷含量。本文系统地总结了七叶一枝花中主要活性成分甾体皂苷的种类,以及不同产地、不同生长年限及不同采收月份的七叶一枝花根茎中甾体皂苷含量差异的研究现状,以期为进一步研究七叶一枝花品质差异、野生资源驯化及规范化种植提供参考。  相似文献   
68.
目的 探讨糖尿病前期的中医证型及证素分布特点。方法 检索中国知网、万方及维普三大数据库中收录的自建库以来有关糖尿病前期证型的临床研究文献,对中医证型进行规范整理,建立数据库,提取证素,运用数据挖掘技术中的关联分析、聚类分析探究证素分布规律。结果 共纳入10篇文献,总有效病例1620例,证型经规范处理后整理为18个,主要证型为脾虚痰湿证。共提取证素13个,主要病位证素为脾,主要病性证素为气虚、湿和痰,关联分析显示脾—湿支持度和置信度最高,聚类分析结果可得到3个聚类组。结论 糖尿病前期病位在脾,气虚、脾、痰、湿是常见证素,临床诊治糖尿病前期应注重从脾论治,需辨证施治。  相似文献   
69.
The objective of the current study was to develop and evaluate a DEep learning-based rapid Spiral Image REconstruction (DESIRE) technique for high-resolution spiral first-pass myocardial perfusion imaging with whole-heart coverage, to provide fast and accurate image reconstruction for both single-slice (SS) and simultaneous multislice (SMS) acquisitions. Three-dimensional U-Net–based image enhancement architectures were evaluated for high-resolution spiral perfusion imaging at 3 T. The SS and SMS MB = 2 networks were trained on SS perfusion images from 156 slices from 20 subjects. Structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), and normalized root mean square error (NRMSE) were assessed, and prospective images were blindly graded by two experienced cardiologists (5: excellent; 1: poor). Excellent performance was demonstrated for the proposed technique. For SS, SSIM, PSNR, and NRMSE were 0.977 [0.972, 0.982], 42.113 [40.174, 43.493] dB, and 0.102 [0.080, 0.125], respectively, for the best network. For SMS MB = 2 retrospective data, SSIM, PSNR, and NRMSE were 0.961 [0.950, 0.969], 40.834 [39.619, 42.004] dB, and 0.107 [0.086, 0.133], respectively, for the best network. The image quality scores were 4.5 [4.1, 4.8], 4.5 [4.3, 4.6], 3.5 [3.3, 4], and 3.5 [3.3, 3.8] for SS DESIRE, SS L1-SPIRiT, MB = 2 DESIRE, and MB = 2 SMS-slice-L1-SPIRiT, respectively, showing no statistically significant difference (p = 1 and p = 1 for SS and SMS, respectively) between L1-SPIRiT and the proposed DESIRE technique. The network inference time was ~100 ms per dynamic perfusion series with DESIRE, while the reconstruction time of L1-SPIRiT with GPU acceleration was ~ 30 min. It was concluded that DESIRE enabled fast and high-quality image reconstruction for both SS and SMS MB = 2 whole-heart high-resolution spiral perfusion imaging.  相似文献   
70.
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