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   517篇
  免费   46篇
  2024年   2篇
  2023年   4篇
  2022年   7篇
  2021年   22篇
  2020年   12篇
  2019年   16篇
  2018年   15篇
  2017年   6篇
  2016年   18篇
  2015年   29篇
  2014年   27篇
  2013年   32篇
  2012年   49篇
  2011年   44篇
  2010年   31篇
  2009年   18篇
  2008年   40篇
  2007年   25篇
  2006年   32篇
  2005年   28篇
  2004年   19篇
  2003年   17篇
  2002年   22篇
  2001年   3篇
  2000年   2篇
  1999年   7篇
  1998年   4篇
  1997年   4篇
  1996年   3篇
  1995年   4篇
  1994年   1篇
  1993年   4篇
  1988年   3篇
  1986年   1篇
  1985年   3篇
  1984年   1篇
  1982年   3篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1961年   1篇
排序方式: 共有563条查询结果,搜索用时 31 毫秒
161.

Background

Inherited ichthyoses represent a group of rare skin disorders characterized by scaling, hyperkeratosis and inconstant erythema, involving most of the tegument. Epidemiology remains poorly described. This study aims to evaluate the prevalence of inherited ichthyosis (excluding very mild forms) and its different clinical forms in France.

Methods

Capture – recapture method was used for this study. According to statistical requirements, 3 different lists (reference/competence centres, French association of patients with ichthyosis and internet network) were used to record such patients. The study was conducted in 5 areas during a closed period.

Results

The prevalence was estimated at 13.3 per million people (/M) (CI95%, [10.9 – 17.6]). With regard to autosomal recessive congenital ichthyosis, the prevalence was estimated at 7/M (CI 95% [5.7 – 9.2]), with a prevalence of lamellar ichthyosis and congenital ichthyosiform erythroderma of 4.5/M (CI 95% [3.7 – 5.9]) and 1.9/M (CI 95% [1.6 – 2.6]), respectively. Prevalence of keratinopathic forms was estimated at 1.1/M (CI 95% [0.9 – 1.5]). Prevalence of syndromic forms (all clinical forms together) was estimated at 1.9/M (CI 95% [1.6 – 2.6]).

Conclusions

Our results constitute a crucial basis to properly size the necessary health measures that are required to improve patient care and design further clinical studies.  相似文献   
162.

Objective

Medical schools struggle with large classes, which might interfere with the effectiveness of learning within small groups due to students being unfamiliar to fellow students. The aim of this study was to assess the effects of making a large class seem small on the students'' collaborative learning processes.

Design

A randomised controlled intervention study was undertaken to make a large class seem small, without the need to reduce the number of students enrolling in the medical programme. The class was divided into subsets: two small subsets (n = 50) as the intervention groups; a control group (n = 102) was mixed with the remaining students (the non-randomised group n∼100) to create one large subset.

Setting

The undergraduate curriculum of the Maastricht Medical School, applying the Problem-Based Learning principles. In this learning context, students learn mainly in tutorial groups, composed randomly from a large class every 6–10 weeks.

Intervention

The formal group learning activities were organised within the subsets. Students from the intervention groups met frequently within the formal groups, in contrast to the students from the large subset who hardly enrolled with the same students in formal activities.

Main Outcome Measures

Three outcome measures assessed students'' group learning processes over time: learning within formally organised small groups, learning with other students in the informal context and perceptions of the intervention.

Results

Formal group learning processes were perceived more positive in the intervention groups from the second study year on, with a mean increase of β = 0.48. Informal group learning activities occurred almost exclusively within the subsets as defined by the intervention from the first week involved in the medical curriculum (E-I indexes>−0.69). Interviews tapped mainly positive effects and negligible negative side effects of the intervention.

Conclusion

Better group learning processes can be achieved in large medical schools by making large classes seem small.  相似文献   
163.
164.
165.
Developing new methods for modelling infectious diseases outbreaks is important for monitoring transmission and developing policy. In this paper we propose using semi-mechanistic Hawkes Processes for modelling malaria transmission in near-elimination settings. Hawkes Processes are well founded mathematical methods that enable us to combine the benefits of both statistical and mechanistic models to recreate and forecast disease transmission beyond just malaria outbreak scenarios. These methods have been successfully used in numerous applications such as social media and earthquake modelling, but are not yet widespread in epidemiology. By using domain-specific knowledge, we can both recreate transmission curves for malaria in China and Eswatini and disentangle the proportion of cases which are imported from those that are community based.  相似文献   
166.
SUMMARY: Among classical methods for module detection, SpaCEM(3) provides ad hoc algorithms that were shown to be particularly well adapted to specific features of biological data: high-dimensionality, interactions between components (genes) and integrated treatment of missingness in observations. The software, currently in its version 2.0, is developed in C++ and can be used either via command line or with the GUI under Linux and Windows environments. AVAILABILITY: The SpaCEM(3) software, a documentation and datasets are available from http://spacem3.gforge.inria.fr/.  相似文献   
167.

Background  

Mycorrhizal fungi form intimate associations with their host plants that constitute their carbon resource and habitat. Alnus spp. (Betulaceae) are known to host an exceptional species-poor and specialized ectomycorrhizal (ECM) fungal community compared to other tree species, but the host-specificity pattern and its significance in terms of fungal diversification and speciation remain poorly documented. The degree of parallel speciation, host switching, and patterns of biogeography were explored in the historical associations between alders and three ECM taxa of Basidiomycetes: Alnicola (Agaricales), Alpova (Boletales), and Lactarius (Russulales). The aim was to develop an evolutionary framework on host specificity and diversification of Basidiomycetes in this highly specialized plant-fungus symbiosis.  相似文献   
168.
A novel series of isoindolo[2,1-a]quinoxaline and indolo[1,2-a]quinoxaline derivatives was synthesized and evaluated in vitro against various human cancer cell lines for antiproliferative activity. These new compounds displayed activity against leukemia and breast cancer cell lines in the 3- to 18-μM concentration range.  相似文献   
169.
Apoptosis is of crucial importance in the life of multicellular organisms. In holometabolous insects, particularly in Lepidoptera, apoptosis is essential in biological processes such as metamorphosis and defense against pathogens. Apoptosis is tightly regulated and involves many proteins, among them caspases, which play a central role. In mammals, almost 300 targets of caspases have been described, and the expression of more than a hundred proteins has been shown to be altered in apoptotic cells. To date, the molecular pathways controlling apoptosis are poorly understood in Lepidoptera. Here, we used a comparative approach aiming to identify candidate proteins potentially implicated in these pathways. We examined changes occurring, in the proteome of a Helicoverpa armigera-derived cell line, upon induction by actinomycin D. We identified 13 proteins for which the relative abundance was significantly altered. Among these, the abundance of procaspase-1 decreased in apoptotic cells, reflecting its processing into the active form. We characterized its properties by heterologous expression and correlated the observed substrate specificity with changes in caspase activity in HaAM1 cells after induction. We also identified three chaperones as well as several putative pro- and anti-apoptotic proteins. Altogether, these data suggest that apoptotic pathways in Lepidoptera share similarities with the ones described in mammals.  相似文献   
170.
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