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   900830篇
  免费   63860篇
  国内免费   2496篇
耳鼻咽喉   12487篇
儿科学   28690篇
妇产科学   26190篇
基础医学   126931篇
口腔科学   24719篇
临床医学   75014篇
内科学   183295篇
皮肤病学   19011篇
神经病学   71608篇
特种医学   36544篇
外国民族医学   337篇
外科学   142338篇
综合类   19575篇
现状与发展   1篇
一般理论   247篇
预防医学   64616篇
眼科学   20185篇
药学   64111篇
  4篇
中国医学   2016篇
肿瘤学   49267篇
  2018年   9149篇
  2017年   7275篇
  2016年   7786篇
  2015年   8885篇
  2014年   12550篇
  2013年   19365篇
  2012年   25878篇
  2011年   27487篇
  2010年   16754篇
  2009年   15907篇
  2008年   26239篇
  2007年   27844篇
  2006年   28024篇
  2005年   27591篇
  2004年   26366篇
  2003年   25542篇
  2002年   25140篇
  2001年   41433篇
  2000年   42623篇
  1999年   36351篇
  1998年   10017篇
  1997年   9201篇
  1996年   9130篇
  1995年   8488篇
  1994年   8108篇
  1993年   7599篇
  1992年   28226篇
  1991年   27000篇
  1990年   26426篇
  1989年   25373篇
  1988年   23578篇
  1987年   23182篇
  1986年   22267篇
  1985年   21178篇
  1984年   15819篇
  1983年   13486篇
  1982年   8091篇
  1979年   14593篇
  1978年   10210篇
  1977年   8628篇
  1976年   8147篇
  1975年   8959篇
  1974年   10697篇
  1973年   10182篇
  1972年   9662篇
  1971年   8917篇
  1970年   8585篇
  1969年   8026篇
  1968年   7684篇
  1967年   7086篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Kinase alterations are increasingly recognised as oncogenic drivers in mesenchymal tumours. Infantile fibrosarcoma and the related renal tumour, congenital mesoblastic nephroma, were among the first solid tumours shown to harbour recurrent tyrosine kinase fusions, with the canonical ETV6::NTRK3 fusion identified more than 20 years ago. Although targeted testing has long been used in diagnosis, the advent of more robust sequencing techniques has driven the discovery of kinase alterations in an array of mesenchymal tumours. As our ability to identify these genetic alterations has improved, as has our recognition and understanding of the tumours that harbour these alterations. Specifically, this study will focus upon mesenchymal tumours harbouring NTRK or other kinase alterations, including tumours with an infantile fibrosarcoma-like appearance, spindle cell tumours resembling lipofibromatosis or peripheral nerve sheath tumours and those occurring in adults with a fibrosarcoma-like appearance. As publications describing the histology of these tumours increase so, too, do the variety kinase alterations reported, now including NTRK1/2/3, RET, MET, RAF1, BRAF, ALK, EGFR and ABL1 fusions or alterations. To date, these tumours appear locally aggressive and rarely metastatic, without a clear link between traditional features used in histological grading (e.g. mitotic activity, necrosis) and outcome. However, most of these tumours are amenable to new targeted therapies, making their recognition of both diagnostic and therapeutic import. The goal of this study is to review the clinicopathological features of tumours with NTRK and other tyrosine kinase alterations, discuss the most common differential diagnoses and provide recommendations for molecular confirmation with associated treatment implications.  相似文献   
2.
3.
社会力量具备相应的经济基础和技术条件,对于公立互联网医院体系建设具有积极的促进作用。但是实践中仍然存在商业模式不完善、监管制度不健全等问题。基于经济学契约理论要义,提出在坚持激励与约束机制并举、平衡公私益关系的前提下,通过完善医保政策、构建互联网医疗服务价格分类管理机制来促进社会力量向医疗服务公益性目标回归,并通过构建完善的监督体制来约束部分社会力量的盲目逐利性行为。  相似文献   
4.
5.
6.
7.
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.  相似文献   
8.
Journal of Immigrant and Minority Health - COVID-19 has disproportionally affected underrepresented minorities (URM) and low-income immigrants in the United States. The aim of the study is to...  相似文献   
9.
10.
In this paper we present a coupled Finite Element Method – Boundary Element Method (FEM-BEM) approach for the solution of the free-boundary axi-symmetric plasma equilibrium problem. The proposed method, obtained from an improvement of the Hagenow-Lackner coupling method, allows to efficiently model the equilibrium problem in unbounded domains by discretizing only the plasma region; the external conductors can be modelled either as 2D or 3D models, according to the problem of interest. The paper explores different iterative methods for the solution of the nonlinear Grad-Shafranov equation, such as Picard, Newton-Raphson and Newton-Krylov, in order to provide a robust and reliable tool, able to handle large-scale problems (e.g. high resolution equilibria). This method has been implemented in the FRIDA code (FRee-boundary Integro-Differential Axisimmetric – https://github. om/matteobonotto/ FRIDA), together with a suitable Adaptive Integration Technique (AIT) for the computation of the source term. FRIDA has been successfully tested and validated against experimental data from RFX-mod device, and numerical equilibria of an ITER-like device.  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