全文获取类型
收费全文 | 204篇 |
免费 | 22篇 |
出版年
2021年 | 4篇 |
2020年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 11篇 |
2013年 | 7篇 |
2012年 | 14篇 |
2011年 | 12篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 10篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 8篇 |
2002年 | 13篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有226条查询结果,搜索用时 15 毫秒
171.
172.
Alexandre Dobly Jan Langeveld Lucien van Keulen Caroline Rodeghiero Stéphanie Durand Riet Geeroms Patrick Van Muylem Jessica De Sloovere Emmanuel Vanopdenbosch Stefan Roels 《BMC veterinary research》2010,6(1):26
Background
The bovine spongiform encephalopathy (BSE) epidemic presented homogeneity of the phenotype. This classical BSE (called C-type) was probably due to the contamination of the food chain by a single prion strain. However, due to the active surveillance and better techniques, two rare variants of BSE have been recently reported in different continents without a clear correlation to the BSE epidemic. These emerging types behave as different strains of BSE and were named H-type and L-type according to the high and low molecular mass of the unglycosylated fragment of their proteinase K resistant prion protein (PrPres). In these types, the proportion of the un-, mono- and di-glycosylated fragments of PrP (glycoprofile) is also atypical and represents an effective diagnostic parameter. This study evaluated the presence of such types in bovine of 7 years and older in Belgium. 相似文献173.
174.
175.
Dros J Maarsingh OR van der Windt DA Oort FJ ter Riet G de Rooij SE Schellevis FG van der Horst HE van Weert HC 《PloS one》2011,6(1):e16481
Background
The diagnostic approach to dizzy, older patients is not straightforward as many organ systems can be involved and evidence for diagnostic strategies is lacking. A first differentiation in diagnostic subtypes or profiles may guide the diagnostic process of dizziness and can serve as a classification system in future research. In the literature this has been done, but based on pathophysiological reasoning only.Objective
To establish a classification of diagnostic profiles of dizziness based on empirical data.Design
Cross-sectional study.Participants and Setting
417 consecutive patients of 65 years and older presenting with dizziness to 45 primary care physicians in the Netherlands from July 2006 to January 2008.Methods
We performed tests, including patient history, and physical and additional examination, previously selected by an international expert panel and based on an earlier systematic review. We used the results of these tests in a principal component analysis for exploration, data-reduction and finally differentiation into diagnostic dizziness profiles.Results
Demographic data and the results of the tests yielded 221 variables, of which 49 contributed to the classification of dizziness into six diagnostic profiles, that may be named as follows: “frailty”, “psychological”, “cardiovascular”, “presyncope”, “non-specific dizziness” and “ENT”. These explained 32% of the variance.Conclusions
Empirically identified components classify dizziness into six profiles. This classification takes into account the heterogeneity and multicausality of dizziness and may serve as starting point for research on diagnostic strategies and can be a first step in an evidence based diagnostic approach of dizzy older patients. 相似文献176.
N.W.J.T. Heinsman P.L.J. van der Weide A. van der Padt M.C.R. Franssen R.M. Boom K. van't Riet 《Biocatalysis and Biotransformation》2013,31(6):429-436
The bench scale Novozym 435 ® catalysed esterification of 4-methyloctanoic acid with ethanol was studied at 35°C. Esterification in a batch reactor (molar ratio of 1:8 (acid:EtOH)) resulted in the isolation of the enantiomerically enriched product (ee p =81%) and substrate (ee s =93%). In order to integrate reaction and separation, liquid-vapour equilibria calculations were performed showing that an excess of ethanol results in a very low ester fraction in the vapour phase. Since this is undesirable for an integrated process of reaction and product removal, a repeated batch reaction was performed using a molar ratio of 10:1 (acid:EtOH). After six cycles (45% conversion) the ee of 4-methyloctanoic acid ethyl ester turned out to be 80%. For different E values the ee p was calculated for batch and repeated batch reactions. It was shown that in all cases the ee p was higher for the repeated batch reaction. However, the product is not enantiopure since the E value of the reaction is rather low at the low ethanol concentration used. An alternative approach would be the continuous separation of the product during the reaction. A mathematical model was developed to describe esterification in a packed bed reactor integrated with product separation. This model shows that integration of reaction and product removal in advance is not suitable either to obtain an enantiomerically pure product. Since the optimal reaction conditions (high ethanol concentration) and the optimal separation system (low ethanol concentration) do not match in this reaction, the preference is given to the batch reaction at high ethanol concentrations because in that case the highest enantioselectivity of the enzyme is obtained. 相似文献
177.
GROWTH REGULATING FACTOR5 Stimulates Arabidopsis Chloroplast Division,Photosynthesis, and Leaf Longevity 总被引:2,自引:0,他引:2
178.
Mitochondrial type-I prohibitins of Arabidopsis thaliana are required for supporting proficient meristem development 总被引:2,自引:0,他引:2
179.
Sarah Snykers Tamara Vanhaecke Ann De Becker Peggy Papeleu Mathieu Vinken Ivan Van Riet Vera Rogiers 《BMC developmental biology》2007,7(1):24
Background
The capability of human mesenchymal stem cells (hMSC) derived of adult bone marrow to undergo in vitro hepatic differentiation was investigated. 相似文献180.
Shomari DL Zack-Williams Peter E Butler Deepak M Kalaskar 《World journal of stem cells》2015,7(1):51-64
Unlike central nervous system neurons; those in the peripheral nervous system have the potential for full regeneration after injury. Following injury, recovery is controlled by schwann cells which replicate and modulate the subsequent immune response. The level of nerve recovery is strongly linked to the severity of the initial injury despite the significant advancements in imaging and surgical techniques. Multiple experimental model shave been used with varying successes to augment the natural regenerative processes which occur following nerve injury. Stem cell therapy in peripheral nerve injury may be an important future intervention to improve the best attainable clinical results. In particular adipose derived stem cells(ADSCs) are multipotent mesenchymal stem cells similar to bone marrow derived stem cells, which are thought to have neurotrophic properties and the ability to differentiate into multiple lineages. They are ubiquitous within adipose tissue; they can form many structures resembling the mature adult peripheral nervous system. Following early in vitro work; multiple small and large animal in vivo models have been used in conjunction with conduits, autografts and allografts to successfully bridge the peripheral nerve gap. Some of the ADSC related neuroprotective and regenerative properties have been elucidated however much work remains before a model can be used successfully in human peripheral nerve injury(PNI). This review aims to provide a detailed overview of progress made in the use of ADSC in PNI, with discussion on the role of a tissue engineered approach for PNI repair. 相似文献