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   25238篇
  免费   1622篇
  国内免费   123篇
耳鼻咽喉   243篇
儿科学   679篇
妇产科学   565篇
基础医学   2866篇
口腔科学   621篇
临床医学   2079篇
内科学   5518篇
皮肤病学   415篇
神经病学   1433篇
特种医学   731篇
外国民族医学   3篇
外科学   4368篇
综合类   777篇
一般理论   22篇
预防医学   1873篇
眼科学   652篇
药学   2287篇
中国医学   257篇
肿瘤学   1594篇
  2023年   226篇
  2022年   694篇
  2021年   1027篇
  2020年   644篇
  2019年   830篇
  2018年   1026篇
  2017年   649篇
  2016年   561篇
  2015年   737篇
  2014年   1010篇
  2013年   1234篇
  2012年   1871篇
  2011年   1816篇
  2010年   1039篇
  2009年   801篇
  2008年   1390篇
  2007年   1298篇
  2006年   1234篇
  2005年   1153篇
  2004年   1034篇
  2003年   913篇
  2002年   763篇
  2001年   604篇
  2000年   534篇
  1999年   432篇
  1998年   163篇
  1997年   133篇
  1996年   131篇
  1995年   131篇
  1994年   79篇
  1993年   88篇
  1992年   224篇
  1991年   222篇
  1990年   182篇
  1989年   196篇
  1988年   154篇
  1987年   176篇
  1986年   139篇
  1985年   151篇
  1984年   126篇
  1983年   98篇
  1982年   71篇
  1981年   70篇
  1979年   112篇
  1978年   78篇
  1977年   73篇
  1975年   68篇
  1974年   66篇
  1973年   65篇
  1972年   54篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
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   
2.
Introduction: Collaborative interactions between several diverse biological processes govern the onset and progression of breast cancer. These processes include alterations in cellular metabolism, anti-tumor immune responses, DNA damage repair, proliferation, anti-apoptotic signals, autophagy, epithelial-mesenchymal transition, components of the non-coding genome or onco-mIRs, cancer stem cells and cellular invasiveness. The last two decades have revealed that each of these processes are also directly regulated by a component of the cell cycle apparatus, cyclin D1.

Area covered: The current review is provided to update recent developments in the clinical application of cyclin/CDK inhibitors to breast cancer with a focus on the anti-tumor immune response.

Expert opinion: The cyclin D1 gene encodes the regulatory subunit of a proline-directed serine-threonine kinase that phosphorylates several substrates. CDKs possess phosphorylation site selectivity, with the phosphate-acceptor residue preceding a proline. Several important proteins are substrates including all three retinoblastoma proteins, NRF1, GCN5, and FOXM1. Over 280 cyclin D3/CDK6 substrates have b\een identified. Given the diversity of substrates for cyclin/CDKs, and the altered thresholds for substrate phosphorylation that occurs during the cell cycle, it is exciting that small molecular inhibitors targeting cyclin D/CDK activity have encouraging results in specific tumors.  相似文献   

3.

Background

The objective of the study was to evaluate the outcomes of clinically localized prostate cancer treated with prostatectomy versus radiation therapy within the context of a prospective prostate cancer screening study.

Patients and Methods

Within the PLCO (Prostate, Lung, Colorectal, and Ovary) trial, patients who were diagnosed with clinically localized prostate cancer and subsequently received treatment with prostatectomy or radiation therapy (with or without hormonal treatment) were included. Univariate and multivariate Cox regression analyses were then performed to determine factors affecting overall and prostate cancer-specific survival. Factors with P < .05 in univariate analysis were included in the multivariate analysis.

Results

A total of 3953 patients were included in the current analysis. These included 2044 patients treated with prostatectomy and 1909 patients treated with radiation therapy with or without hormonal treatment. In an adjusted multivariate analysis for factors affecting overall survival, prostatectomy was associated with better overall survival compared with radiation therapy (hazard ratio, 0.548; 95% confidence interval [CI], 0.440- 681; P < .001). Likewise, in an adjusted multivariate analysis for factors affecting prostate cancer-specific survival, prostatectomy was associated with better prostate cancer-specific survival compared with radiation therapy (hazard ratio, 0.485; 95% CI, 0.286- 0.822; P = .007). Similar findings were found with propensity score matching and repeating the same analyses on the post-matching cohort.

Conclusion

Prostatectomy seems to predict better overall and prostate cancer-specific survival compared with radiation therapy among patients with clinically localized prostate cancer diagnosed within the PLCO trial.  相似文献   
4.
BACKGROUND Approximately 20% of patients with neuroendocrine tumours(NETs) develop carcinoid syndrome(CS),characterised by flushing and diarrhoea.Somatostatin analogues or telotristat can be used to control symptoms of CS through inhibition of serotonin secretion.Although CS is often the cause of diarrhoea among patients with gastroenteropancreatic NETs(GEP-NETs),other causes to consider include pancreatic enzyme insufficiency(PEI),bile acid malabsorption and small intestinal bacterial overgrowth.If other causes of diarrhoea unrelated to serotonin secretion are mistaken for CS diarrhoea,these treatments may be ineffective against the diarrhoea,risking detrimental effects to patient quality of life.AIM To identify and synthesise qualitative and quantitative evidence relating to the differential diagnosis of diarrhoea in patients with GEP-NETs.METHODS Electronic databases(MEDLINE,Embase and the Cochrane Library) were searched from inception to September 12,2018 using terms for NETs and diarrhoea.Congresses,systematic literature review bibliographies and included articles were also hand-searched.Any study designs and publication types were eligible for inclusion if relevant data on a cause(s) of diarrhoea in patients with GEP-NETs were reported.Studies were screened by two independent reviewers at abstract and full-text stages.Framework synthesis was adapted to synthesise quantitative and qualitative data.The definition of qualitative data was expanded to include all textual data in any section of relevant publications.RESULTS Forty-seven publications(44 studies) were included,comprising a variety of publication types,including observational studies,reviews,guidelines,case reports,interventional studies,and opinion pieces.Most reported on PEI on/after treatment with somatostatin analogs;9.5%-84% of patients with GEP-NETs had experienced steatorrhoea or confirmed PEI.Where reported,14.3%–50.7% of patients received pancreatic enzyme replacement therapy.Other causes of diarrhoea reported in patients with GEP-NETs included bile acid malabsorption(80%),small intestinal bacterial overgrowth(23.6%-62%),colitis(20%) and infection(7.1%).Diagnostic approaches included faecal elastase,breath tests,tauroselcholic(selenium-75) acid(Se HCAT) scan and stool culture,although evidence on the effectiveness or diagnostic accuracy of these approaches was limited.Assessment of patient history or diarrhoea characteristics was also reported as initial approaches for investigation.From the identified evidence,if diarrhoea is assumed to be CS diarrhoea,consequences include uncontrolled diarrhoea,malnutrition,and perceived ineffectiveness of CS treatment.Approaches for facilitating differential diagnosis of diarrhoea include improving patient and clinician awareness of non-CS causes and involvement of a multidisciplinary clinical team,including gastroenterologists.CONCLUSION Diarrhoea in GEP-NETs can be multifactorial with misdiagnosis leading to delayed patient recovery and inefficient resource use.This systematic literature review highlights gaps for further research on prevalence of non-CS diarrhoea and suitability of diagnostic approaches,to determine an effective algorithm for differential diagnosis of GEP-NET diarrhoea.  相似文献   
5.
6.
Dosage form is a mean used for the delivery of drug to a living body. In order to get the desired effect the drug should be delivered to its site of action at such rate and concentration to achieve the maximum therapeutic effect and minimum adverse effect. Since oral route is still widely accepted route but having a common drawback of difficulty in swallowing of tablets and capsules. Therefore a lot of research has been done on novel drug delivery systems. This review is about oral dispersible tablets a novel approach in drug delivery systems that are now a day''s more focused in formulation world, and laid a new path that, helped the patients to build their compliance level with the therapy, also reduced the cost and ease the administration especially in case of pediatrics and geriatrics. Quick absorption, rapid onset of action and reduction in drug loss properties are the basic advantages of this dosage form.  相似文献   
7.
8.
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