全文获取类型
收费全文 | 287篇 |
免费 | 29篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 11篇 |
2017年 | 11篇 |
2016年 | 15篇 |
2015年 | 29篇 |
2014年 | 32篇 |
2013年 | 28篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 9篇 |
2009年 | 16篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 13篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 3篇 |
1995年 | 5篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有316条查询结果,搜索用时 15 毫秒
121.
Minela Haskovic Britt Derks Liesbeth van der Ploeg Jorn Trommelen Jean Nyakayiru Luc J. C. van Loon Sabrina Mackinnon Wyatt W. Yue Roy W. A. Peake Li Zha Didem Demirbas Wanshu Qi Xiaoping Huang Gerard T. Berry Jelle Achten Jörgen Bierau M. Estela Rubio-Gozalbo Ana I. Coelho 《Orphanet journal of rare diseases》2018,13(1):212
Background
Classic galactosemia is a rare genetic metabolic disease with an unmet treatment need. Current standard of care fails to prevent chronically-debilitating brain and gonadal complications.Many mutations in the GALT gene responsible for classic galactosemia have been described to give rise to variants with conformational abnormalities. This pathogenic mechanism is highly amenable to a therapeutic strategy based on chemical/pharmacological chaperones. Arginine, a chemical chaperone, has shown beneficial effect in other inherited metabolic disorders, as well as in a prokaryotic model of classic galactosemia.The p.Q188R mutation presents a high prevalence in the Caucasian population, making it a very clinically relevant mutation. This mutation gives rise to a protein with lower conformational stability and lower catalytic activity. The aim of this study is to assess the potential therapeutic role of arginine for this mutation.Methods
Arginine aspartate administration to four patients with the p.Q188R/p.Q188R mutation, in vitro studies with three fibroblast cell lines derived from classic galactosemia patients as well as recombinant protein experiments were used to evaluate the effect of arginine in galactose metabolism. This study has been registered at https://clinicaltrials.gov (NCT03580122) on 09 July 2018. Retrospectively registered.Results
Following a month of arginine administration, patients did not show a significant improvement of whole-body galactose oxidative capacity (p =?0.22), erythrocyte GALT activity (p =?0.87), urinary galactose (p =?0.52) and urinary galactitol levels (p =?0.41). Patients’ fibroblasts exposed to arginine did not show changes in GALT activity. Thermal shift analysis of recombinant p.Q188R GALT protein in the presence of arginine did not exhibit a positive effect.Conclusions
This short pilot study in four patients homozygous for the p.Q188R/p.Q188R mutation reveals that arginine has no potential therapeutic role for galactosemia patients homozygous for the p.Q188R mutation.122.
Lazaros Neokosmidis Thomas Tscheulin Jelle Devalez Theodora Petanidou 《Insect Science》2018,25(1):172-182
The majority of studies investigating the effects of landscape composition and configuration on bee populations have been conducted in regions of intensive agricultural production, ignoring regions which are dominated by seminatural habitats, such as the islands of the Aegean Archipelago. In addition, research so far has focused on the landscape impacts on bees sampled in cropped fields while the landscape effects on bees inhabiting seminatural habitats are understudied. Here, we investigate the impact of the landscape on wild bee assemblages in 66 phryganic (low scrubland) communities on 8 Aegean islands. We computed landscape metrics (total area and total perimeter–area ratio) in 4 concentric circles (250, 500, 750, and 1000 m) around the center of each bee sampling site including 3 habitat groups (namely phrygana, cultivated land, and natural forests). We further measured the local flower cover in 25 quadrats distributed randomly at the center of each sampling site. We found that the landscape scale is more important than the local scale in shaping abundance and species richness of bees. Furthermore, habitat configuration was more important than the total area of habitats, probably because it affects bees’ movement across the landscape. Phrygana and natural forests had a positive effect on bee demographics, while cultivated land had a negative effect. This demonstrates that phryganic specialists drive bee assemblages in these seminatural landscapes. This finding, together with the shown importance of landscape scale, should be considered for the management of wild bees with special emphasis placed on the spatial configuration of seminatural habitats. 相似文献
123.
Isolation of protein complexes from the model legume Medicago truncatula by tandem affinity purification in hairy root cultures 下载免费PDF全文
124.
Paola F. Borroni Jelle Atema 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1988,164(1):67-74
1. | The self-adapting effects of chemical backgrounds on the response of primary chemoreceptor cells to superimposed stimuli were studied using lobster (Homarus americanus) NH4 receptor cells. |
2. | These receptors responded for several seconds to the onset of the backgrounds, and then returned to their initial level of spontaneous activity (usually zero). The strongest response always occurred only during the steepest concentration change; the response then decayed back to zero or to the earlier spontaneous firing level, while the background concentration was still rising, and remained silent during the entire time that the background was maintained constant (20–30 min) (Fig. 2). |
3. | Exposure to constant self-adapting backgrounds eliminated the responses of NH4 receptor cells to stimuli of concentration lower than the background, and reduced the responses to all higher stimulus concentrations tested by a nearly equal amount. This resulted in a parallel shift of the stimulus-response function to the right along the abscissa (Figs. 3 and 4). |
4. | Since the response threshold was completely re-set by adaptation to backgrounds, NH4 receptors seem to function mostly as detectors of relative rather than absolute stimulus intensity across their entire dynamic range: the response to a given stimulus-to-background ratio remained the same over 3 log step increases of background concentration (Fig. 6). |
5. | As in other sensory modalities, a parallel shift of response functions appears to be an important property of chemoreceptor cells, allowing for this sensory system to function over a wider stimulus intensity range than the instantaneous dynamic range of individual receptor cells. |
125.
126.
Aranka M. van der Burgh Jelle Postma Silke Robatzek Matthieu H. A. J. Joosten 《Molecular Plant Pathology》2019,20(3):410-422
Leucine-rich repeat-receptor-like proteins (LRR-RLPs) and LRR-receptor-like kinases (LRR-RLKs) trigger immune signalling to promote plant resistance against pathogens. LRR-RLPs lack an intracellular kinase domain, and several of these receptors have been shown to constitutively interact with the LRR-RLK Suppressor of BIR1-1/EVERSHED (SOBIR1/EVR) to form signalling-competent receptor complexes. Ligand perception by LRR-RLPs initiates recruitment of the co-receptor BRI1-Associated Kinase 1/Somatic Embryogenesis Receptor Kinase 3 (BAK1/SERK3) to the LRR-RLP/SOBIR1 complex, thereby activating LRR-RLP-mediated immunity. We employed phosphorylation analysis of in planta-produced proteins, live cell imaging, gene silencing and co-immunoprecipitation to investigate the roles of SOBIR1 and BAK1 in immune signalling. We show that Arabidopsis thaliana (At) SOBIR1, which constitutively activates immune responses when overexpressed in planta, is highly phosphorylated. Moreover, in addition to the kinase activity of SOBIR1 itself, kinase-active BAK1 is essential for AtSOBIR1-induced constitutive immunity and for the phosphorylation of AtSOBIR1. Furthermore, the defence response triggered by the tomato LRR-RLP Cf-4 on perception of Avr4 from the extracellular pathogenic fungus Cladosporium fulvum is dependent on kinase-active BAK1. We argue that, in addition to the trans-autophosphorylation of SOBIR1, it is likely that SOBIR1 and BAK1 transphosphorylate, and thereby activate the receptor complex. The signalling-competent cell surface receptor complex subsequently activates downstream cytoplasmic signalling partners to initiate RLP-mediated immunity. 相似文献
127.
Jelle S. Zijlstra Donald A. McFarlane Lars W. Van Den Hoek Ostende Joyce Lundberg 《Palaeontology》2014,57(5):895-908
Cordimus, a new genus of cricetid rodent, is described from Neogene deposits on the islands of Curaçao and Bonaire, Dutch Antilles. The genus is characterized by strongly cuspidate molars, the presence of mesolophs in most upper molars and the absence of mesolophids in lower molars. Similarities with the early cricetid Copemys from the Miocene of North America coupled with apparent derived characters shared with the subfamily Sigmodontinae suggest that Cordimus may be close to the root of the sigmodontine lineage, a possibility that remains to be tested through explicit phylogenetic analysis. Three species are recognized on the basis of size and details of molar morphology. Cordimus hooijeri sp. nov. is described from Bonaire on the basis of Holocene owl pellet material that consists of dentaries and postcranial material only. This species is presumed to be extinct, but focused surveys are needed to confirm this hypothesis. Cordimus debuisonjei sp. nov. and Cordimus raton sp. nov. are described from deposits on Tafelberg Santa Barbara in Curaçao. Although the age of these deposits is not known, they are most likely of late Pliocene or early Pleistocene age. Both are represented by numerous isolated molars and some osteological material. 相似文献
128.
Joachim Vansteenkiste Jelle Van Loon Sarah Garré Loïc Pagès Eddie Schrevens Jan Diels 《Plant and Soil》2014,375(1-2):75-88
Background and aims
Root length density (RLD) is a parameter that is difficult to measure, but crucial to estimate water and nutrient uptake by plants. In this study a novel approach is presented to characterize the 3-D root length distribution by supplementing data of the 3-D distribution of root intersections with data of root length density from a limited number of soil cores.Methods
The method was evaluated in a virtual experiment using the RootTyp model and a field experiment with cauliflower (Brassica oleracea L. botrytis) and leek (Allium porrum, L.).Results
The virtual experiment shows that total root length and root length distribution can be accurately estimated using the novel approach. Implementation of the method in a field experiment was successful for characterizing the growth of the root distribution with time both for cauliflower and leek. In contrast with the virtual experiment, total root length could not be estimated based upon root intersection measurements in the field.Conclusions
The novel method of combining root intersection data with root length density data from core samples is a powerful tool to supply root water uptake models with root system information. 相似文献129.
Nathalie Fieremans Marijke Bauters Stefanie Belet Jelle Verbeeck Anna C. Jansen Sara Seneca Filip Roelens Elfride De Baere Peter Marynen Guy Froyen 《Human genetics》2014,133(11):1359-1367
Xq28 microduplications of MECP2 are a prominent cause of a severe syndromic form of intellectual disability (ID) in males. Females are usually unaffected through near to complete X-inactivation of the aberrant X chromosome (skewing). In rare cases, affected females have been described due to random X-inactivation. Here, we report on two female patients carrying de novo MECP2 microduplications on their fully active X chromosomes. Both patients present with ID and additional clinical features. Mono-allelic expression confirmed complete skewing of X-inactivation. Consequently, significantly enhanced MECP2 mRNA levels were observed. We hypothesize that the cause for the complete skewing is due to a more harmful mutation on the other X chromosome, thereby forcing the MECP2 duplication to become active. However, we could not unequivocally identify such a second mutation by array-CGH or exome sequencing. Our data underline that, like in males, increased MECP2 dosage in females can contribute to ID too, which should be taken into account in diagnostics. 相似文献