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   2589168篇
  免费   211719篇
  国内免费   8384篇
耳鼻咽喉   37951篇
儿科学   87671篇
妇产科学   69276篇
基础医学   360292篇
口腔科学   69855篇
临床医学   252276篇
内科学   520464篇
皮肤病学   58700篇
神经病学   214827篇
特种医学   98023篇
外国民族医学   913篇
外科学   387313篇
综合类   52323篇
现状与发展   74篇
一般理论   868篇
预防医学   207902篇
眼科学   57187篇
药学   183569篇
  7篇
中国医学   5470篇
肿瘤学   144310篇
  2021年   22775篇
  2019年   23150篇
  2018年   35693篇
  2017年   28445篇
  2016年   31785篇
  2015年   34793篇
  2014年   51491篇
  2013年   71987篇
  2012年   86087篇
  2011年   91186篇
  2010年   59113篇
  2009年   58408篇
  2008年   84655篇
  2007年   88052篇
  2006年   89665篇
  2005年   84597篇
  2004年   80763篇
  2003年   76691篇
  2002年   74354篇
  2001年   112979篇
  2000年   116315篇
  1999年   98485篇
  1998年   30729篇
  1997年   27768篇
  1996年   27543篇
  1995年   26127篇
  1994年   23788篇
  1993年   21942篇
  1992年   77075篇
  1991年   75537篇
  1990年   72962篇
  1989年   69746篇
  1988年   64391篇
  1987年   63111篇
  1986年   59604篇
  1985年   56895篇
  1984年   43078篇
  1983年   36503篇
  1982年   21866篇
  1981年   19671篇
  1979年   38585篇
  1978年   27349篇
  1977年   22918篇
  1976年   21877篇
  1975年   23010篇
  1974年   27376篇
  1973年   26649篇
  1972年   24581篇
  1971年   22579篇
  1970年   21232篇
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
11.
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   
12.
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   
13.
14.
15.
16.

The exercise pressor reflex is a feedback mechanism engaged upon stimulation of mechano- and metabosensitive skeletal muscle afferents. Activation of these afferents elicits a reflex increase in heart rate, blood pressure, and ventilation in an intensity-dependent manner. Consequently, the exercise pressor reflex has been postulated to be one of the principal mediators of the cardiorespiratory responses to exercise. In this updated review, we will discuss classical and recent advancements in our understating of the exercise pressor reflex function in both human and animal models. Particular attention will be paid to the afferent mechanisms and pathways involved during its activation, its effects on different target organs, its potential role in the abnormal cardiovascular response to exercise in diseased states, and the impact of age and biological sex on these responses. Finally, we will highlight some unanswered questions in the literature that may inspire future investigations in the field.

  相似文献   
17.
18.
19.
20.
Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid malignancy with high mortality rate. This malignancy arises in thyroid follicular cells either denovo or with an associated differentiated thyroid carcinoma component. Clinically, it usually presents as a rapidly enlarging mass, pain and locally compressive symptoms. Histopathologic variability and heterogeneity often pose diagnostic challenges, especially in scant and paucicellular specimens. This article describes the clinical, histopathologic and molecular features of ATC and also addresses the associated diagnostic limitations and challenges.  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