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   4220篇
  免费   316篇
  国内免费   17篇
耳鼻咽喉   61篇
儿科学   122篇
妇产科学   66篇
基础医学   753篇
口腔科学   118篇
临床医学   405篇
内科学   779篇
皮肤病学   112篇
神经病学   612篇
特种医学   138篇
外科学   431篇
综合类   18篇
一般理论   2篇
预防医学   262篇
眼科学   94篇
药学   277篇
中国医学   8篇
肿瘤学   295篇
  2024年   3篇
  2023年   33篇
  2022年   50篇
  2021年   136篇
  2020年   74篇
  2019年   106篇
  2018年   111篇
  2017年   116篇
  2016年   147篇
  2015年   176篇
  2014年   205篇
  2013年   233篇
  2012年   380篇
  2011年   347篇
  2010年   221篇
  2009年   194篇
  2008年   286篇
  2007年   301篇
  2006年   328篇
  2005年   249篇
  2004年   223篇
  2003年   183篇
  2002年   145篇
  2001年   50篇
  2000年   23篇
  1999年   39篇
  1998年   39篇
  1997年   23篇
  1996年   11篇
  1995年   12篇
  1994年   6篇
  1993年   8篇
  1992年   15篇
  1991年   7篇
  1990年   9篇
  1989年   6篇
  1988年   6篇
  1987年   6篇
  1986年   8篇
  1985年   2篇
  1984年   5篇
  1983年   3篇
  1982年   2篇
  1979年   3篇
  1976年   3篇
  1971年   2篇
  1970年   2篇
  1966年   2篇
  1946年   1篇
  1933年   1篇
排序方式: 共有4553条查询结果,搜索用时 46 毫秒
91.
92.
Right ventricular (RV) failure is a common problem for adults with systemic right ventricles or volume-overloaded right ventricles. The utility of B-type natriuretic peptide (BNP) levels for diagnosis and prognosis is now well documented in adults with acquired left ventricular (LV) systolic dysfunction, but not in the setting of RV failure. BNP levels were evaluated in adults with RV failure due to congenital heart disease and compared with levels in adults with acquired LV dysfunction and adults without structural heart disease.  相似文献   
93.
Atherosclerotic carotid artery stenosis is a major cause of disabling stroke or death. Although carotid endarterectomy (CEA) is currently considered to be the standard of care for patients with a severe symptomatic stenosis and selected patients with an asymptomatic carotid stenosis, carotid angioplasty and stenting (CAS) is increasingly being used as an alternative treatment modality. This article briefly summarizes the current trial data on CEA and CAS. More importantly, potential risk factors for CEA and CAS are reviewed and the complementary role of these techniques in the management of the individual patient is discussed.  相似文献   
94.
95.
Digestive Diseases and Sciences - Little is known about patient choice in treatment of eosinophilic esophagitis (EoE). Determine motivators and barriers to using common EoE therapies and describe...  相似文献   
96.
97.
The Arrhenius parameters of the propagation rate coefficient, kp, are determined via the pulsed laser polymerization—size exclusion chromatography (PLP‐SEC) method for five branched acrylates (tert‐butyl (tBA), isobornyl (iBoA), benzyl (BnA), 2‐ethylhexyl (EHA), and 2‐propylheptyl acrylate (PHA)) in 1 m solution in butyl acetate (BuAc) to complete the series, published by Haehnel et al. in 2014, of branched acrylates (isononyl (INA‐A), tridecyl (TDA‐A and TDN‐A), heptadecyl (C17A), and henicosyl acrylate (C21A)) in solution that do not show a trend in kp. Furthermore, the propagation rate coefficients of the branched acrylates in 1 m solution are critically compared with the branched acrylates in bulk as well as branched methacrylates. A summary of the trends and family‐type behavior for the linear and branched (meth)acrylates as well as methacrylates with cyclic ester side chains is provided. For the branched acrylates in 1 m solution, no clear trends of the propagation rate coefficients, kp, or Arrhenius parameters A and EA are detectable and—in contrast to the corresponding methacrylates—there is no family‐type behavior observed in solution as well as in bulk.

  相似文献   

98.
Glasses in the system BaO/SrO/ZnO/SiO2 containing 0.01 and 0.1 mol% gold were used to study the formation of gold nanoparticles with the aim to use them as nucleation agents. In order to promote gold clustering, the glasses were additionally doped with 0.5 mol% Sb2O3. Depending on the heat treatment schedule, Au particle sizes were in the range from 6 to above 50 nm. In contrast to many other gold ruby glass systems, the clustering is completely prevented by the absence of antimony; then the glasses remain colorless. Surprisingly, at higher temperatures, a re-dissolution of gold clusters was also observed, which now allows the formulation of a more comprehensive model concerning the redox and clustering behavior. This growth model is completed by the fact that a high gold concentration enables the stabilization of much smaller Au clusters. Mie theory with the aid of quantum confined size-dependent dielectric functions was successfully used to describe the optical behavior of the gold nanoparticles also for sizes below 10 nm. These results were confirmed using high resolution scanning transmission electron microscopy, including energy dispersive X-ray spectroscopy. It could also be shown that small gold particles up to a size of 50 nm are not effective as nucleating agents.

Glasses in the system BaO/SrO/ZnO/SiO2 containing 0.01 and 0.1 mol% gold were used to study the formation of gold nanoparticles with the aim to use them as nucleation agents.  相似文献   
99.
It has been shown previously that cryopreservation, using an ice‐free cryopreservation method with the cryoprotectant formulation VS83, beneficially modulated immune reactions in vivo and in vitro when compared with conventionally frozen tissues. In this study, we assessed the impact of a VS83 post‐treatment of previously conventionally frozen human tissue on responses of human immune cells in vitro. Tissue punches of treated and non‐treated (control) aortic heart valve tissue (leaflets and associated aortic root) were co‐cultured for 7 days with peripheral blood mononuclear cells or enriched CD14+ monocytes. Effects on cellular activation markers, cytokine secretion and immune cell proliferation were analysed by flow cytometry. Flow cytometry studies showed that VS83 treatment of aortic root tissue promoted activation and differentiation of CD14+ monocytes, inducing both up‐regulation of CD16 and down‐regulation of CD14. Significantly enhanced expression levels for the C‐C chemokine receptor (CCR)7 and the human leukocyte antigen (HLA)‐DR on monocytes co‐cultured with VS83‐treated aortic root tissue were measured, while the interleukin (IL)‐6 and monocyte chemoattractant protein (MCP)‐1 release was suppressed. However, the levels of interferon (IFN)γ and tumour necrosis factor (TNF)α remained undetectable, indicating that complete activation into pro‐inflammatory macrophages did not occur. Similar, but non‐significant, changes occurred with VS83‐treated leaflets. Additionally, in co‐cultures with T cells, proliferation and cytokine secretion responses were minimal. In conclusion, post‐treatment of conventionally cryopreserved human heart valve tissue with the VS83 formulation induces changes in the activation and differentiation characteristics of human monocytes, and thereby may influence long‐term performance following implantation. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
100.

Background

The EINSTEIN-Jr program will evaluate rivaroxaban for the treatment of venous thromboembolism (VTE) in children, targeting exposures similar to the 20 mg once-daily dose for adults. A physiologically based pharmacokinetic (PBPK) model for pediatric rivaroxaban dosing has been constructed.

Methods

We quantitatively assessed the pharmacokinetics (PK) of a single rivaroxaban dose in children using population pharmacokinetic (PopPK) modelling and assessed the applicability of the PBPK model. Plasma concentration–time data from the EINSTEIN-Jr phase I study were analysed by non-compartmental and PopPK analyses and compared with the predictions of the PBPK model. Two rivaroxaban dose levels, equivalent to adult doses of rivaroxaban 10 mg and 20 mg, and two different formulations (tablet and oral suspension) were tested in children aged 0.5–18 years who had completed treatment for VTE.

Results

PK data from 59 children were obtained. The observed plasma concentration–time profiles in all subjects were mostly within the 90% prediction interval, irrespective of dose or formulation. The PopPK estimates and non-compartmental analysis-derived PK parameters (in children aged ≥6 years) were in good agreement with the PBPK model predictions.

Conclusions

These results confirmed the applicability of the rivaroxaban pediatric PBPK model in the pediatric population aged 0.5–18 years, which in combination with the PopPK model, will be further used to guide dose selection for the treatment of VTE with rivaroxaban in EINSTEIN-Jr phase II and III studies.

Trial registration

ClinicalTrials.gov number, NCT01145859; registration date: 17 June 2010.
  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