全文获取类型
收费全文 | 5971篇 |
免费 | 569篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 77篇 |
儿科学 | 187篇 |
妇产科学 | 124篇 |
基础医学 | 855篇 |
口腔科学 | 140篇 |
临床医学 | 551篇 |
内科学 | 1355篇 |
皮肤病学 | 263篇 |
神经病学 | 462篇 |
特种医学 | 258篇 |
外国民族医学 | 3篇 |
外科学 | 893篇 |
综合类 | 48篇 |
预防医学 | 434篇 |
眼科学 | 119篇 |
药学 | 431篇 |
中国医学 | 20篇 |
肿瘤学 | 333篇 |
出版年
2023年 | 32篇 |
2022年 | 66篇 |
2021年 | 166篇 |
2020年 | 126篇 |
2019年 | 189篇 |
2018年 | 211篇 |
2017年 | 151篇 |
2016年 | 171篇 |
2015年 | 163篇 |
2014年 | 210篇 |
2013年 | 262篇 |
2012年 | 363篇 |
2011年 | 364篇 |
2010年 | 248篇 |
2009年 | 206篇 |
2008年 | 299篇 |
2007年 | 266篇 |
2006年 | 282篇 |
2005年 | 255篇 |
2004年 | 191篇 |
2003年 | 202篇 |
2002年 | 174篇 |
2001年 | 167篇 |
2000年 | 149篇 |
1999年 | 134篇 |
1998年 | 70篇 |
1997年 | 81篇 |
1996年 | 79篇 |
1995年 | 68篇 |
1994年 | 64篇 |
1993年 | 56篇 |
1992年 | 138篇 |
1991年 | 115篇 |
1990年 | 80篇 |
1989年 | 78篇 |
1988年 | 77篇 |
1987年 | 70篇 |
1986年 | 79篇 |
1985年 | 72篇 |
1984年 | 43篇 |
1983年 | 33篇 |
1982年 | 34篇 |
1981年 | 31篇 |
1979年 | 20篇 |
1978年 | 26篇 |
1976年 | 23篇 |
1974年 | 19篇 |
1971年 | 15篇 |
1970年 | 16篇 |
1969年 | 21篇 |
排序方式: 共有6553条查询结果,搜索用时 703 毫秒
991.
Mitnick CD Shin SS Seung KJ Rich ML Atwood SS Furin JJ Fitzmaurice GM Alcantara Viru FA Appleton SC Bayona JN Bonilla CA Chalco K Choi S Franke MF Fraser HS Guerra D Hurtado RM Jazayeri D Joseph K Llaro K Mestanza L Mukherjee JS Muñoz M Palacios E Sanchez E Sloutsky A Becerra MC 《The New England journal of medicine》2008,359(6):563-574
992.
993.
Kroneman A Verhoef L Harris J Vennema H Duizer E van Duynhoven Y Gray J Iturriza M Böttiger B Falkenhorst G Johnsen C von Bonsdorff CH Maunula L Kuusi M Pothier P Gallay A Schreier E Höhne M Koch J Szücs G Reuter G Krisztalovics K Lynch M McKeown P Foley B Coughlan S Ruggeri FM Di Bartolo I Vainio K Isakbaeva E Poljsak-Prijatelj M Grom AH Mijovski JZ Bosch A Buesa J Fauquier AS Hernandéz-Pezzi G Hedlund KO Koopmans M 《Journal of clinical microbiology》2008,46(9):2959-2965
The Foodborne Viruses in Europe network has developed integrated epidemiological and virological outbreak reporting with aggregation and sharing of data through a joint database. We analyzed data from reported outbreaks of norovirus (NoV)-caused gastroenteritis from 13 European countries (July 2001 to July 2006) for trends in time and indications of different epidemiology of genotypes and variants. Of the 13 countries participating in this surveillance network, 11 were capable of collecting integrated epidemiological and virological surveillance data and 10 countries reported outbreaks throughout the entire period. Large differences in the numbers and rates of reported outbreaks per country were observed, reflecting the differences in the focus and coverage of national surveillance systems. GII.4 strains predominated throughout the 5-year surveillance period, but the proportion of outbreaks associated with GII.4 rose remarkably during years in which NoV activity was particularly high. Spring and summer peaks indicated the emergence of genetically distinct variants within GII.4 across Europe and were followed by increased NoV activity during the 2002-2003 and 2004-2005 winter seasons. GII.4 viruses predominated in health care settings and in person-to-person transmission. The consecutive emergence of new GII.4 variants is highly indicative of immune-driven selection. Their predominance in health care settings suggests properties that facilitate transmission in settings with a high concentration of people such as higher virus loads in excreta or a higher incidence of vomiting. Understanding the mechanisms driving the changes in epidemiology and clinical impact of these rapidly evolving RNA viruses is essential to design effective intervention and prevention measures. 相似文献
994.
Hastings CE Fisher CA McCabe MA;National Clinical Research Nursing Consortium Allison J Brassil D Offenhartz M Browning S DeCandia E Medina R Duer-Hefele J McClary K Mullen N Ottosen M Britt S Sanchez T Turbini V 《Nursing outlook》2012,60(3):149-156.e1-3
Translational clinical research has emerged as an important priority for the national research enterprise, with a clearly stated mandate to more quickly deliver prevention strategies, treatments and cures based on scientific innovations to the public. Within this national effort, a lack of consensus persists concerning the need for clinical nurses with expertise and specialized training in study implementation and the delivery of care to research participants. This paper reviews efforts to define and document the role of practicing nurses in implementing studies and coordinating clinical research in a variety of clinical settings, and differentiates this clinical role from the role of nurses as scientists and principal investigators. We propose an agenda for building evidence that having nurses provide and coordinate study treatments and procedures can potentially improve research efficiency, participant safety, and the quality of research data. We also provide recommendations for the development of the emerging specialty of clinical research nursing. 相似文献
995.
996.
LN Barlow-Mosha DS Bagenda PK Mudiope MC Mubiru LM Butler MG Fowler PM Musoke 《African health sciences》2012,12(3):249-258
Background
Access to pediatric antiretroviral formulations is increasing in resource-limited countries, however adult FDCs are still commonly used by antiretroviral therapy (ART) programs.Objective
To describe long-term effectiveness of using adult FDC of d4T+3TC+NVP (Triomune) in children for HIV treatment.Methods
Clinical, immunologic, and virologic outcomes of HIV-infected ART-naïve children aged six months to 12 years, were evaluated up to 96 weeks post-ART initiation.Results
From March 2004 to June 2006, 104 children were followed with a median age of 5.4 years, median CD4 cell percent and HIV-1 RNA were 11.0% (IQR 6.7–13.9) and 348,846copies/mL (IQR 160,941–681,313) respectively at baseline. Using Kaplan-Meir estimates, 75% of children had undetectable viral loads (<400copies/mL) at 96weeks of ART. Children with a baseline CD4 cell percent >15% were 3 times more likely to achieve viral load <400copies/mL than those with baseline CD4 cell percent <5% after adjusting for baseline age {aHR = 3.03 (1.10–8.32), p=0.03}; no difference was found among those with CD4 cell percent >5–14.9% and <5%.Conclusion
Treatment with generic adult FDC for HIV-infected Ugandan children led to sustained clinical, immunologic and virologic response during 96 weeks of ART. Early initiation of ART is key to achieving virological success. 相似文献997.
Beatriz Lopez‐Escobar Beatriz De Felipe Jose Antonio Sanchez‐Alcazar Takako Sasaki Andrew J. Copp Patricia Ybot‐Gonzalez 《Developmental dynamics》2012,241(11):1808-1815
Background: The ventral ectodermal ridge (VER) is an important signalling centre in the mouse tail‐bud following completion of gastrulation. BMP regulation is essential for VER function, but how these signals are transmitted between adjacent tissues is unclear. Results: We investigated the idea that extracellular matrix components might be involved, using immunohistochemistry and in situ hybridisation to detect all known α, β, and γ laminin chains and their mRNAs in the early tail bud. We identified an apparently novel laminin variant, comprising α5, β3 and γ2 chains, as a major component of the VER basement membrane at E9.5. Strikingly, only the mRNAs for these chains were co‐expressed in VER cells, suggesting that lamin532 may be the sole basement membrane laminin at this stage. Since α6 integrin was also expressed in VER cells, this raises the possibility of cell‐matrix interactions regulating BMP signalling at this site of caudal morphogenesis. Conclusions: Laminin532 could interact with α6‐containing integrin to direct differentiation of the specialised VER cells from surface ectoderm. Developmental Dynamics 241:1808–1815, 2012. © 2012 Wiley Periodicals Inc. 相似文献
998.
Low vision aid in exudative macular degeneration
treated by photodynamic therapy and thermal laser
photocoagulation
下载免费PDF全文
![点击此处可从《国际眼科》网站下载免费的PDF全文](/ch/ext_images/free.gif)
To determine the efficacy of low vision rehabilitation (LVR) in patients with age-related macular degeneration (AMD) treated by photodynamic therapy (PDT) compared to those treated by thermal laser photocoagulation (TLP).
· METHODS: A retrospective study was performed examining the files of 42 patients (42 eyes) with AMD who had been treated either by TLP (Group 1) and PDT (Group 2). Once AMD was considered to be inactive they underwent visual rehabilitation in the LVR Unit in order to increase their ability for distant and near vision.
· RESULTS: Eighteen eyes had received PDT and 24 had received TLP. Average corrected visual acuity after laser therapy was 0.14 in Group 1, and 0.16 in Group 2. No statistically significant differences were found between both groups before and after laser therapy. Both groups showed improvement after LVR; however, statistically significant differences between both groups were found only for near vision.
· CONCLUSION: Our findings suggest that even though both PDT and TLP are associated to a decreased visual acuity after treatment, LVR may be more successful for near vision among patients treated by PDT 相似文献
999.
1000.
Alzheimer's disease (AD) is a complex, multifactorial progressive neurodegenerative disease. Pathologically, AD is characterized by extracellular deposits of amyloid beta (Aβ) protein and intracellular accumulation of neurofibrillary tangles (NFTs) of tau. The central role of Aβ protein in the AD etiology is well-established, and its increased deposition in AD brain is attributed to its decreased clearance from the brain. It is noteworthy that apolipoprotein E (ApoE), the most significant risk factor for late-onset AD, has been shown to play a vital role in brain Aβ clearance and the ability of ApoE to do this depends mainly upon its lipidation status. Thus, lower ApoE lipidation status leading to decreased Aβ clearance may underlie the increased Aβ deposition observed in AD brain. In addition to the pathophysiological Aβ deposits, AD is also characterized by certain metabolic changes. Among them, decreased cerebral glucose metabolism is one of the distinct characteristics of AD brain and is also observed in patients with Mild Cognitive Impairment (MCI) who subsequently develop AD. Thus, decreased cerebral glucose metabolism is an early event in AD pathology and may precede the neuropathological Aβ deposition associated with AD. In this context, we hypothesize here that the decreased glucose metabolism in pre-AD and early AD stages, may lead to lower ApoE lipidation status, which in turn may lead to decreased clearance and hence, increased deposition of Aβ protein in AD brain. 相似文献