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   4120385篇
  免费   300205篇
  国内免费   16904篇
耳鼻咽喉   56777篇
儿科学   132990篇
妇产科学   112577篇
基础医学   585815篇
口腔科学   113806篇
临床医学   384455篇
内科学   791053篇
皮肤病学   94079篇
神经病学   331315篇
特种医学   155870篇
外国民族医学   1211篇
外科学   611606篇
综合类   101906篇
现状与发展   39篇
一般理论   1605篇
预防医学   320921篇
眼科学   96835篇
药学   307578篇
  128篇
中国医学   13797篇
肿瘤学   223131篇
  2021年   36912篇
  2019年   36023篇
  2018年   48419篇
  2017年   37232篇
  2016年   42025篇
  2015年   48607篇
  2014年   67175篇
  2013年   98182篇
  2012年   132932篇
  2011年   141490篇
  2010年   85220篇
  2009年   80099篇
  2008年   129888篇
  2007年   137722篇
  2006年   139723篇
  2005年   135065篇
  2004年   128224篇
  2003年   123545篇
  2002年   118991篇
  2001年   185418篇
  2000年   190420篇
  1999年   161685篇
  1998年   49219篇
  1997年   43476篇
  1996年   43085篇
  1995年   41348篇
  1994年   37915篇
  1993年   35328篇
  1992年   125536篇
  1991年   121627篇
  1990年   118211篇
  1989年   114478篇
  1988年   105324篇
  1987年   103184篇
  1986年   97068篇
  1985年   93011篇
  1984年   69459篇
  1983年   59132篇
  1982年   35254篇
  1979年   62955篇
  1978年   44749篇
  1977年   37779篇
  1976年   35566篇
  1975年   37987篇
  1974年   45311篇
  1973年   43168篇
  1972年   40615篇
  1971年   38151篇
  1970年   35128篇
  1969年   33808篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Quality of Life Research - The COVID-19 pandemic might add to the stressors experienced by people living with rheumatic diseases. This study aimed to examine rheumatic patients’ functional...  相似文献   
2.
Molnár  B.  Aroca  S.  Dobos  A.  Orbán  K.  Szabó  J.  Windisch  P.  Stähli  A.  Sculean  A. 《Clinical oral investigations》2022,26(12):7135-7142
Clinical Oral Investigations - To evaluate t he long-term outcomes following treatment of RT 1 multiple adjacent gingival recessions (MAGR) using the modified coronally advanced tunnel (MCAT) with...  相似文献   
3.
目的 了解我国老年人中医证候分布特征,为中医药辨治老年人提供参考依据。方法 系统检索中国知识基础设施(CNKI)、中文科技期刊数据库(CCD)、万方数据资源系统数据库(CSPD),纳入研究对象为老年人的临床流行病学调查研究文献,对其调查目的、调查疾病及调查结果等进行描述统计。结果 ①最终纳入168篇文献,其中2010至2020年之间发表138篇(82.14%);调查地区涵盖全国28个省市自治区,共纳入43948例老年人,累计覆盖340个研究中心;②主要研究结果显示,老年人中医证候阴虚阳亢证(10.05%)>血瘀证(9.5%)>痰浊(湿)证(8.91%)>阴阳两虚证(4.98%)>痰瘀互结证(4.96%);单元证分布阴虚证(14.70%)>痰证(11.22%)>气虚证(7.15%)>肾虚证(4.72%)>血瘀证(4.18%);涉及病变脏腑肾>肝>脾>肺>心。结论 根据统计结果,可以看出老年人证候分布虚证多于实证,虚证中又以阴虚证、气虚证最为多见,实证常见血瘀证、痰浊(湿)证等,且多见痰瘀互结证;老年人五脏皆损,其中又以肾、肝、脾功能失调最为突出。  相似文献   
4.

Interstitial lung disease (ILD) represents a significant cause of morbidity and mortality in systemic sclerosis (SSc). The purpose of this study was to examine recirculating lymphocytes from SSc patients for potential biomarkers of interstitial lung disease (ILD). Peripheral blood mononuclear cells (PBMCs) were isolated from patients with SSc and healthy controls enrolled in the Vanderbilt University Myositis and Scleroderma Treatment Initiative Center cohort between 9/2017–6/2019. Clinical phenotyping was performed by chart abstraction. Immunophenotyping was performed using both mass cytometry and fluorescence cytometry combined with t-distributed stochastic neighbor embedding analysis and traditional biaxial gating. This study included 34 patients with SSc-ILD, 14 patients without SSc-ILD, and 25 healthy controls. CD21lo/neg cells are significantly increased in SSc-ILD but not in SSc without ILD (15.4 ± 13.3% vs. 5.8 ± 0.9%, p = 0.002) or healthy controls (5.0 ± 0.5%, p < 0.0001). While CD21lo/neg B cells can be identified from a single biaxial gate, tSNE analysis reveals that the biaxial gate is comprised of multiple distinct subsets, all of which are increased in SSc-ILD. CD21lo/neg cells in both healthy controls and SSc-ILD are predominantly tBET positive and do not have intracellular CD21. Immunohistochemistry staining demonstrated that CD21lo/neg B cells diffusely infiltrate the lung parenchyma of an SSc-ILD patient. Additional work is needed to validate this biomarker in larger cohorts and longitudinal studies and to understand the role of these cells in SSc-ILD.

  相似文献   
5.
6.
7.
Intratumor heterogeneity is a main cause of the dismal prognosis of glioblastoma (GBM). Yet, there remains a lack of a uniform assessment of the degree of heterogeneity. With a multiscale approach, we addressed the hypothesis that intratumor heterogeneity exists on different levels comprising traditional regional analyses, but also innovative methods including computer-assisted analysis of tumor morphology combined with epigenomic data. With this aim, 157 biopsies of 37 patients with therapy-naive IDH-wildtype GBM were analyzed regarding the intratumor variance of protein expression of glial marker GFAP, microglia marker Iba1 and proliferation marker Mib1. Hematoxylin and eosin stained slides were evaluated for tumor vascularization. For the estimation of pixel intensity and nuclear profiling, automated analysis was used. Additionally, DNA methylation profiling was conducted separately for the single biopsies. Scoring systems were established to integrate several parameters into one score for the four examined modalities of heterogeneity (regional, cellular, pixel-level and epigenomic). As a result, we could show that heterogeneity was detected in all four modalities. Furthermore, for the regional, cellular and epigenomic level, we confirmed the results of earlier studies stating that a higher degree of heterogeneity is associated with poorer overall survival. To integrate all modalities into one score, we designed a predictor of longer survival, which showed a highly significant separation regarding the OS. In conclusion, multiscale intratumor heterogeneity exists in glioblastoma and its degree has an impact on overall survival. In future studies, the implementation of a broadly feasible heterogeneity index should be considered.  相似文献   
8.
Journal of Medical Ultrasonics - Chronic liver disease is still a major problem because disease progression will ultimately lead to liver cirrhosis. Portal hypertension is the hallmark in advanced...  相似文献   
9.
10.
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