全文获取类型
收费全文 | 530篇 |
免费 | 30篇 |
出版年
2023年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 10篇 |
2015年 | 19篇 |
2014年 | 21篇 |
2013年 | 33篇 |
2012年 | 34篇 |
2011年 | 38篇 |
2010年 | 18篇 |
2009年 | 13篇 |
2008年 | 43篇 |
2007年 | 26篇 |
2006年 | 25篇 |
2005年 | 26篇 |
2004年 | 38篇 |
2003年 | 25篇 |
2002年 | 29篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 2篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1931年 | 2篇 |
排序方式: 共有560条查询结果,搜索用时 140 毫秒
71.
Margit Bak Jensen Merete Studnitz Ulrich Halekoh Lene Juul Pedersen Erik Jrgensen 《Applied animal behaviour science》2008,112(3-4):270-283
The aim of this experiment was to investigate pigs’ preferences for rooting materials. Eighteen materials were allocated to six categories each of which consisted of three similar materials based on characteristics such as structure, size of particles, complexity, destructibility and digestibility. Twelve pairs of pigs chose among the three materials of each of the six categories in a balanced design. Within each category each pair was given four instantaneous choices among the three materials in a three-armed maze. ‘No choice’ was scored if the pigs did not enter one of the maze-arms within 90 s. Thus there were four options in each choice situation. The results were analysed using a random utility model incorporating random intercepts to account for the repeated testing of the same animals. The pigs expressed clear preferences within the category EARTH, where compost and peat were preferred to wood-shavings and no choice. In the category CHIP the most probable rank-order was spruce chip, willow chip, fir chip and no choice, while in the category ROUGH the most probable rank-order was maize-silage, grass silage, sugar beets and no choice. However, in these two categories none of the probabilities were sufficiently large to signify a preference for any of the three materials although the probabilities of the ‘no choice’ option were low. The pigs expressed no preferences among any of the four options including ‘no choice’ in the categories TOY (sisal robe, Bite-Rite, wooden beam), HAY (alfalfa hay mixed with straw, seed grass hay, barley straw with under-seed), and STRAW (long straw, chopped straw and straw pellets). 相似文献
72.
Petersen BO Sára M Mader C Mayer HF Sleytr UB Pabst M Puchberger M Krause E Hofinger A Duus JØ Kosma P 《Carbohydrate research》2008,343(8):1346-1358
The secondary cell wall polymer (SCWP) from Geobacillus stearothermophilus PV72/p2, which is involved in the anchoring of the surface-layer protein to the bacterial cell wall layer, is composed of 2-amino-2-deoxy- and 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-mannose, and 2-acetamido-2-deoxy-D-mannuronic acid. The primary structure of the acid-degraded polysaccharide--liberated by HF-treatment from the cell wall--was determined by high-field NMR spectroscopy and mass spectrometry using N-acetylated and hydrolyzed polysaccharide derivatives as well as Smith-degradation. The polysaccharide was shown to consist of a tetrasaccharide repeating unit containing a pyruvic acid acetal at a side-chain 2-acetamido-2-deoxy-alpha-D-mannopyranosyl residue. Substoichiometric substitutions of the repeating unit were observed concerning the degree of N-acetylation of glucosamine residues and the presence of side-chain linked 2-acetamido-2-deoxy-beta-D-glucopyranosyl units: [Formula: see text]. 相似文献
73.
Tazreiter M Leitsch D Hatzenbichler E Mair-Scorpio GE Steinborn R Schreiber M Duchêne M 《Experimental parasitology》2008,120(4):403-410
Entamoeba histolytica remains a cause of significant morbidity and mortality in many countries. Although metronidazole has been used for the treatment of amoebiasis for several decades, little is known on how the amoebae react to this challenge on the levels of mRNA and protein expression. In this study, we examined their response using a focused microarray, quantitative RT-PCR, and two-dimensional gel electrophoresis (2DE). The amoebae modestly increased the levels of mRNA coding for superoxide dismutase, peroxiredoxin, ferredoxin, thioredoxin reductase, and the galactose/N-acetylgalactosamine specific lectin light and heavy chains. The mRNAs encoding actin and the 70 kDa and 101 kDa heat shock proteins were decreased. All the changes occured within 1 h of exposition, with very little further changes. In addition, the proteome revealed only very few changes. Taken together, E. histolytica appears to make only modest mRNA and protein expression changes when confronted with an unknown chemical stress. 相似文献
74.
Margit A Huber Andrea Denk Ralf U Peter Lutz Weber Norbert Kraut Thomas Wirth 《The Journal of biological chemistry》2002,277(2):1268-1275
Tumor necrosis factor (TNF)-alpha-induced phosphorylation of the IkappaB proteins by the IkappaB kinase (IKK) complex containing IKK-2 and subsequent degradation of the IkappaB proteins are prerequisites for NF-kappaB activation, resulting in the stimulation of a variety of pro-inflammatory target genes. The C-C chemokine eotaxin-1 is a potent chemoattractant for eosinophils and Th2 lymphocytes, may play an important role in the pathogenesis of atopic dermatitis, and acts via binding to its receptor CCR3. To investigate the role of NF-kappaB signaling in the regulation of these genes, we stably expressed a transdominant mutant of IkappaBalpha and a constitutively active mutant of IKK-2 in mouse NIH3T3 fibroblasts. The transdominant IkappaBalpha mutant completely inhibited TNF-alpha-mediated induction of both eotaxin-1 and CCR3, whereas expression of constitutively active IKK-2 was sufficient to drive almost full expression of these two genes in the absence of TNF-alpha. Moreover, we observed elevated expression levels of CCR3 and eotaxin-1 protein levels in the skin of IkappaBalpha-deficient mice characterized by a widespread dermatitis. Finally, using dermal fibroblasts derived from IkappaBalpha-deficient mice, we observed elevated basal expression, enhanced inducibility by TNF-alpha, and attenuated down-regulation upon TNF-alpha withdrawal of both CCR3 and eotaxin-1 mRNA levels. These results demonstrate that the IKK-2/IkappaBalpha/NF-kappaB pathway plays a critical role for CCR3 and eotaxin-1 expression in fibroblasts and suggests a critical link to the pathogenesis of atopic dermatitis. 相似文献
75.
Ocular retardation is a recessive murine mutation whose phenotypic expression is greatly affected by genetic background effects.
Mice of the inbred 129/SvJ background that are homozygous for the Chx10or-J mutation are blind and have a thin, poorly differentiated retina and no optic nerve. A backcross between 129/SvJ and Mus musculus castaneus (CASA/Rk) produced animals that were homozygous for the Chx10or-J mutation, yet showed a much milder phenotype. Such animals, when brother-sister mated and selected for mild phenotype for
several generations, resulted in partial recovery of visual function, including presence of an optic nerve and pupillary response.
In this article we report a genome scan of phenotypic extremes of the backcross to identify the genetic loci affecting this
phenotype modification. Our scan revealed significant loci on Chromosomes 6 and 14 where the CASA/Rk alleles are maintained
selectively. Markers were developed near candidate genes, but no candidate gene could be identified unequivocally.
Electronic Supplementary Material Electronic Supplementary material is available for this article at and accessible for authorised users. 相似文献
76.
77.
Foliar and soil application in concentrations below the recommended rate of the herbicide 3-amino-1,2,4-triazole to the host plantPhaseolus vulgaris L. results in structural alterations of the protein-synthesizing apparatus of midgut and salivary-gland cells of the phytophagous spider miteTetranychus urticae Koch (Acari: Tetranychidae) independent of its mode of application. With prolonged incubation times cytological defects become more intense, and spread to more cells and tissues. Resultant effects on yolk and egg formation were expressed as an inhibition of egg deposition that led to a decrease in the reproduction rate ofT. urticae.Consequences of 3-amino-1,2,4-triazole action onT. urticae are discussed with regard to its value to a host-plant/parasite model, agricultural practices and environmental impacts. 相似文献
78.
A. Bresinsky Margit Jarosch M. Fischer Ines Schönberger Birgit Wittmann-Bresinsky 《Plant biology (Stuttgart, Germany)》1999,1(3):327-333
Abstract: This study aimed to test the monophyly and present a generic concept of Paxillus s. I. Of special interest were the Southern hemisphere representatives of this genus. Using the primer combination LR0R-LR5, DNA sequence data were generated from the nuclear encoded 28S gene. A data set containing 900 bases was created for 30 different species. Phylogenetic analysis showed 3 main monophyletic groups, also supported by morphological, anatomical, ecological and chemical data. Taxonomic interpretation of these clearly differentiated groups corresponded to the genera PaxilIus s. str. and Tapinella and lead to the proposal of a new Southern hemisphere genus, Austro-paxillus , mycorrhizal with Nothofagus . New combinations are proposed. 相似文献
79.
Anna Andersson Omid Rasool Margit Schmidt Rimantas Kodzius Sabine Flückiger Arezou Zargari Reto Crameri Annika Scheynius 《European journal of biochemistry》2004,271(10):1885-1894
Malassezia sympodialis is an opportunistic yeast that colonizes human skin and may induce IgE and T cell reactivity in patients with atopic eczema/dermatitis syndrome (AEDS). Previously, we have cloned and expressed six recombinant allergens (rMala s 1 and rMala s 5 to rMala s 9) from this yeast. By combining high throughput screening and phage surface display techniques, 27 complete and partial IgE-binding clones of M. sympodialis have been identified. Here we enlarged the panel of recombinant M. sympodialis allergens by RACE-PCR, cloning and nucleotide sequencing to obtain the coding sequences of two new IgE-binding clones. The coding sequences of one of the clones showed similarity to the heat shock protein (HSP) family and the other to manganese superoxide dismutase (MnSOD), and both had a high degree of homology to human counterparts. The coding sequences were expressed in Escherichia coli as six-histidine tagged recombinant proteins and generated products with molecular masses of 86.1 kDa for HSP and 22.4 kDa for MnSOD. Their IgE-binding frequencies were shown to be 69% and 75%, respectively, to 28 sera from AEDS patients with serum IgE to M. sympodialis extract, indicating that HSP and MnSOD are major M. sympodialis allergens. In inhibition immunoblotting, M. sympodialis extract could inhibit the binding of serum IgE from AEDS patients to rHSP and rMnSOD in a concentration-dependent manner. The high frequency of sera from AEDS patients, showing IgE binding to both HSP and MnSOD, indicates that these allergens, designated Mala s 10 and Mala s 11, could play a role in AEDS. 相似文献
80.
Molecular Characterization of the S-Layer Gene, sbpA, of Bacillus sphaericus CCM 2177 and Production of a Functional S-Layer Fusion Protein with the Ability To Recrystallize in a Defined Orientation while Presenting the Fused Allergen 下载免费PDF全文
Nicola Ilk Christine Vllenkle Eva M. Egelseer Andreas Breitwieser Uwe B. Sleytr Margit Sra 《Applied microbiology》2002,68(7):3251-3260
The nucleotide sequence encoding the crystalline bacterial cell surface (S-layer) protein SbpA of Bacillus sphaericus CCM 2177 was determined by a PCR-based technique using four overlapping fragments. The entire sbpA sequence indicated one open reading frame of 3,804 bp encoding a protein of 1,268 amino acids with a theoretical molecular mass of 132,062 Da and a calculated isoelectric point of 4.69. The N-terminal part of SbpA, which is involved in anchoring the S-layer subunits via a distinct type of secondary cell wall polymer to the rigid cell wall layer, comprises three S-layer-homologous motifs. For screening of amino acid positions located on the outer surface of the square S-layer lattice, the sequence encoding Strep-tag I, showing affinity to streptavidin, was linked to the 5′ end of the sequence encoding the recombinant S-layer protein (rSbpA) or a C-terminally truncated form (rSbpA31-1068). The deletion of 200 C-terminal amino acids did not interfere with the self-assembly properties of the S-layer protein but significantly increased the accessibility of Strep-tag I. Thus, the sequence encoding the major birch pollen allergen (Bet v1) was fused via a short linker to the sequence encoding the C-terminally truncated form rSpbA31-1068. Labeling of the square S-layer lattice formed by recrystallization of rSbpA31-1068/Bet v1 on peptidoglycan-containing sacculi with a Bet v1-specific monoclonal mouse antibody demonstrated the functionality of the fused protein sequence and its location on the outer surface of the S-layer lattice. The specific interactions between the N-terminal part of SbpA and the secondary cell wall polymer will be exploited for an oriented binding of the S-layer fusion protein on solid supports to generate regularly structured functional protein lattices. 相似文献