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   63525篇
  免费   4180篇
  国内免费   1071篇
耳鼻咽喉   493篇
儿科学   1543篇
妇产科学   1862篇
基础医学   7208篇
口腔科学   1246篇
临床医学   5392篇
内科学   15241篇
皮肤病学   1075篇
神经病学   6216篇
特种医学   2478篇
外国民族医学   2篇
外科学   8658篇
综合类   2122篇
现状与发展   1篇
一般理论   5篇
预防医学   2963篇
眼科学   902篇
药学   4995篇
  8篇
中国医学   975篇
肿瘤学   5391篇
  2023年   613篇
  2022年   872篇
  2021年   2448篇
  2020年   1547篇
  2019年   1733篇
  2018年   2005篇
  2017年   1542篇
  2016年   1685篇
  2015年   2040篇
  2014年   2627篇
  2013年   3227篇
  2012年   4391篇
  2011年   4357篇
  2010年   2520篇
  2009年   2294篇
  2008年   3547篇
  2007年   3613篇
  2006年   3353篇
  2005年   3107篇
  2004年   2877篇
  2003年   2487篇
  2002年   2188篇
  2001年   1547篇
  2000年   1456篇
  1999年   1387篇
  1998年   597篇
  1997年   444篇
  1996年   453篇
  1995年   368篇
  1994年   326篇
  1993年   277篇
  1992年   742篇
  1991年   640篇
  1990年   573篇
  1989年   586篇
  1988年   497篇
  1987年   455篇
  1986年   439篇
  1985年   336篇
  1984年   293篇
  1983年   233篇
  1982年   138篇
  1981年   112篇
  1979年   217篇
  1978年   133篇
  1977年   112篇
  1974年   126篇
  1973年   128篇
  1972年   126篇
  1971年   112篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Wang  Di  Tao  Xiaogen  Fei  Mingming  Chen  Jian  Guo  Wei  Li  Ping  Wang  Jinquan 《Journal of neurovirology》2020,26(3):442-448

Pseudorabies virus (PRV) primarily infects swine but can infect cattle, dogs, and cats. Several studies have reported that PRV can cross the specie barrier and induce human encephalitis, but a definitive diagnosis of human PRV encephalitis is debatable due to the lack of PRV DNA detection. Here, we report a case of human PRV encephalitis diagnosed by the next-generation sequencing (NGS) of PRV sequences in the cerebrospinal fluid (CSF) of a patient. A male pork vendor developed fever and seizures for 6 days. NGS results showed PRV sequences in his CSF and blood. Sanger sequencing showed that PRV DNA in the CSF and PRV antibodies in both the CSF and blood were positive. MRI results revealed multiple inflammatory lesions in the bilateral hemisphere. Based on the clinical and laboratory data, we diagnosed the patient with PRV encephalitis. This case suggests that PRV can infect humans, causing severe viral encephalitis. People at risk of PRV infection should improve their self-protection awareness.

  相似文献   
12.
Background: Extracellular matrix molecular components, previously linked to multisystem syndromes include collagens, fibrillins and laminins. Recently, we described a novel multisystem syndrome caused by the c.9418G>A p.(V3140M) mutation in the laminin alpha-5 (LAMA5) gene, which affects connective tissues of all organs and apparatus in a three generation family. In the same family, we have also reported a myopic trait, which, however, was linked to the Prolyl 4-hydroxylase subunit alpha-2 (P4HA2) gene. Results of investigation on vitreous changes and their pathogenesis are reported in the present study.Materials and Methods: Nineteen family individuals underwent complete ophthalmic examination including best-corrected visual acuity (BCVA), fundus examination, fundus photography, intraocular pressure measurement, axial length measurement using ocular biometry, Goldmann visual field examination, standard electroretinogram, SD-OCT. Segregation analysis of LAMA5 and P4HA2 mutations was performed in enrolled members.Results: The vitreous alterations fully segregated with LAMA5 mutation in both young and adult family members. Slight reduction of retinal thickness and peripheral retinal degeneration in only two patients were reported.Conclusions: In this work we showed that PVD is a common trait of LAMA5 multisystem syndrome, therefore occurring as an age-unrelated trait. We hypothesize that the p.(V3140M) mutation results in a reduction of retinal inner limiting membrane (ILM) stability, leading to a derangement in the macromolecular structure of the vitreous gel, and PVD. Further investigations will be necessary to elucidate the role of wild type and mutated LAMA5 in the pathogenesis of PVD.  相似文献   
13.
Brain Imaging and Behavior - Motor learning is a multi-stage process, in which the involvement of different brain regions is related to the specific stage. We aimed at characterising short...  相似文献   
14.
目的评估血肌酐和尿常规的常规检测基础上联合血清胱抑素C和尿微量白蛋白检测在人类免疫缺陷病毒(HIV)感染者肾功能损伤检测中的应用价值。 方法以2019年2~5月于首都医科大学附属北京地坛医院感染一科住院的169例HIV感染者为研究对象,完善其尿常规、尿微量白蛋白、血肌酐、血清胱抑素C检测;分析尿蛋白及尿微量白蛋白的阳性检出率及其差异,血肌酐升高及血清胱抑素C升高的比例及其差异。计算应用替诺福韦酯(TDF)及合并丙型肝炎、高血压、糖尿病、肿瘤的肾功能损伤的相对危险度。 结果169例HIV感染者中尿常规示尿蛋白阳性者5例(3.0%),尿微量白蛋白升高者17例(10.1%),两者阳性检出率差异具有统计学意义(χ2 = 5.9、P = 0.007)。血肌酐升高者10例(5.9%),血清胱抑素C升高者20例(11.8%),两者阳性检出率差异具有统计学意义(χ2 = 3.0、P = 0.042)。在尿常规和血肌酐检测的基础上联合检测尿微量白蛋白和血清胱抑素C的总体阳性检出率为49例(30.0%)。CD4+ T淋巴细胞计数< 200个/μl与≥ 200个/μl组患者血清胱抑素C水平分别为0.94(0.83,1.05)mg/L、0.85(0.77,0.95)mg/L,差异具有统计学意义(Z =-3.02、P = 0.003)。应用TDF及合并丙型肝炎、高血压、糖尿病、肿瘤的肾功能损伤的相对危险度分别为1.1、1.5、1.9、2.2和1.4。 结论HIV感染者中,单纯以尿常规为依据评估有无蛋白尿,以血肌酐水平为依据评估肾小球滤过功能会低估肾功能损伤的患病率。在常规检测血肌酐和尿常规的基础上联合检测血清胱抑素C和尿微量白蛋白在提高HIV感染者肾功能损伤检出率方面具有重要的应用价值。低CD4+ T淋巴细胞计数、应用TDF及合并丙型肝炎、高血压、糖尿病、肿瘤均为肾功能损伤的危险因素。  相似文献   
15.
To evaluate the changes in alveolar contour after guided bone regeneration (GBR) with two different combinations of biomaterials in dehiscence defects arou  相似文献   
16.
Colorectal cancer (CRC) screening programs help diagnose cancer precursors and early cancers and help reduce CRC mortality. However, currently recommended tests, the fecal immunochemical test (FIT) and colonoscopy, have low uptake. There is therefore a pressing need for screening strategies that are minimally invasive and consequently more acceptable to patients, most likely blood based, to increase early CRC identification. MicroRNAs (miRNAs) released from cancer cells are detectable in plasma in a remarkably stable form, making them ideal cancer biomarkers. Using plasma samples from FIT-positive (FIT+) subjects in an Italian CRC screening program, we aimed to identify plasma circulating miRNAs that detect early CRC. miRNAs were initially investigated by quantitative real-time PCR in plasma from 60 FIT+ subjects undergoing colonoscopy at Fondazione IRCCS Istituto Nazionale dei Tumori, then tested on an internal validation cohort (IVC, 201 cases) and finally in a large multicenter prospective series (external validation cohort [EVC], 1121 cases). For each endoscopic lesion (low-grade adenoma [LgA], high-grade adenoma [HgA], cancer lesion [CL]), specific signatures were identified in the IVC and confirmed on the EVC. A two-miRNA-based signature for CL and six-miRNA signatures for LgA and HgA were selected. In a multivariate analysis including sex and age at blood collection, the areas under the receiver operating characteristic curve (95% confidence interval) of the signatures were 0.644 (0.607–0.682), 0.670 (0.626–0.714) and 0.682 (0.580–0.785) for LgA, HgA and CL, respectively. A miRNA-based test could be introduced into the FIT+ workflow of CRC screening programs so as to schedule colonoscopies only for subjects likely to benefit most.  相似文献   
17.
18.
19.
20.
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