全文获取类型
收费全文 | 310篇 |
免费 | 42篇 |
国内免费 | 1篇 |
出版年
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 5篇 |
2019年 | 8篇 |
2018年 | 7篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 12篇 |
2013年 | 9篇 |
2012年 | 22篇 |
2011年 | 13篇 |
2010年 | 21篇 |
2009年 | 15篇 |
2008年 | 10篇 |
2007年 | 13篇 |
2006年 | 7篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 8篇 |
2002年 | 5篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1994年 | 2篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1975年 | 7篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1969年 | 3篇 |
1968年 | 2篇 |
1967年 | 4篇 |
1965年 | 2篇 |
1948年 | 1篇 |
排序方式: 共有353条查询结果,搜索用时 46 毫秒
91.
A Vernay S Schaub I Guillas M Bassilana RA Arkowitz 《The Journal of cell biology》2012,198(4):711-730
Membrane lipids have been implicated in many critical cellular processes, yet little is known about the role of asymmetric lipid distribution in cell morphogenesis. The phosphoinositide bis-phosphate PI(4,5)P(2) is essential for polarized growth in a range of organisms. Although an asymmetric distribution of this phospholipid has been observed in some cells, long-range gradients of PI(4,5)P(2) have not been observed. Here, we show that in the human pathogenic fungus Candida albicans a steep, long-range gradient of PI(4,5)P(2) occurs concomitant with emergence of the hyphal filament. Both sufficient PI(4)P synthesis and the actin cytoskeleton are necessary for this steep PI(4,5)P(2) gradient. In contrast, neither microtubules nor asymmetrically localized mRNAs are critical. Our results indicate that a gradient of PI(4,5)P(2), crucial for filamentous growth, is generated and maintained by the filament tip-localized PI(4)P-5-kinase Mss4 and clearing of this lipid at the back of the cell. Furthermore, we propose that slow membrane diffusion of PI(4,5)P(2) contributes to the maintenance of such a gradient. 相似文献
92.
van Loo KM Schaub C Pernhorst K Yaari Y Beck H Schoch S Becker AJ 《The Journal of biological chemistry》2012,287(19):15489-15501
93.
Thomas S. Reichlin Michael Schaub Myles H. M. Menz Murielle Mermod Patricia Portner Rapha?l Arlettaz Lukas Jenni 《Journal of Ornithology》2009,150(2):393-400
For many bird species, recovery of ringed individuals remains the best source of information about their migrations. In this
study, we analyzed the recoveries of ringed European Hoopoe (Upupa epops) and the Eurasian Wryneck (Jynx torquilla) from 1914 to 2005 from all European ringing schemes. The aim was to define general migration directions and to make inferences
about the winter quarters, knowing that hardly any recoveries are available from sub-Saharan Africa. For the autumn migration,
there is evidence of a migratory divide for the Hoopoe in Central Europe, at approximately 10–12°E. Autumn migration directions
of Wrynecks gradually change from SW to SE depending on the longitude (west to east) of the ringing place. In both species,
only a few recoveries were available indicating spring migration directions, but they showed similar migration axes as for
autumn migration, and hence no evidence for loop-migration. Due to a paucity of recoveries on the African continent, we can make only limited
inferences about wintering grounds: extrapolating migration directions are only indicative of the longitude of the wintering
area. The directions of autumn migration indicate a typical pattern observed in European long-distance migrants: west-European
Hoopoes and Wrynecks are likely to winter in western Africa, while central- and east-European birds probably winter more in
the east. Due to the migratory divide, for the Hoopoe, this phenomenon is more pronounced. 相似文献
94.
In recent decades, farmland bird populations have declined strongly as a consequence of agriculture intensification. Birds
may have lost breeding sites, food supply or other crucial resources, with the role of multiple factors often remaining unclear.
The ant-eating and cavity-breeding Wryneck (Jynx torquilla) may be limited by the availability of cavities, the number of ants or their accessibility. By comparing occupied and unoccupied
breeding territories, we investigated the relative role of these factors in the decline of Wrynecks. We compared the characteristics
of known Wryneck breeding territories (availability of breeding cavities, food abundance and ground vegetation structure)
with randomly selected, fictitious territories (n = 154) in Western Switzerland. We also studied environmental factors that may affect ant nest density. The probability of
territory occupancy strongly increased with both nestbox availability and ant abundance. In addition, this probability peaked
around 50% of bare ground cover. Habitat types that harbour low ant abundance such as cropland and grassland were avoided.
Ant nest density decreased with increasing amounts of bare ground, and it was particularly high in vineyards. Our results
showed that breeding cavities, food availability and its accessibility all limit Wryneck distribution. The maintenance and
restoration of ant rich grassland, interspersed with patches of bare ground and with hollow trees or dedicated nestboxes in
the surroundings, are essential to preserve Wryneck populations. Such a habitat structure could be achieved even in intensively
farmed habitats, such as in vineyards or fruit tree plantations. 相似文献
95.
96.
Isolation and characterization of a cDNA encoding for a lysozyme from the gut of the reduviid bug Triatoma infestans 总被引:1,自引:0,他引:1
Kollien AH Fechner S Waniek PJ Schaub GA 《Archives of insect biochemistry and physiology》2003,53(3):134-145
We have isolated and characterised a Triatoma infestans cDNA encoding a lysozyme. A 174-bp fragment was amplified by PCR using degenerate oligodeoxyribonucleotide primers derived from the known amino acid sequences of lysozyme from other insects. This PCR fragment was used to screen a cDNA gut library of T. infestans. A clone containing the 3'-end of the lysozyme cDNA (219 bp) was isolated and sequenced. RACE was used to amplify the 5'-end of the lysozyme cDNA. After sequencing the complete lysozyme cDNA, the deduced 417 amino acid sequence showed high identity (40-50%) with other chicken-type lysozymes. The amino acid residues responsible for the catalytic activity and the binding of the substrate were essentially conserved. The expression pattern of the lysozyme gene in bugs at different molting and feeding states showed that this gene was upregulated in the digestive tract directly after the molt and after feeding. Additionally, this lysozyme gene was expressed differently in the different regions of the digestive tract, strongly in the cardia and stomach, the anterior regions of the midgut, and only traces of lysozyme mRNA could be detected in the small intestine, the posterior region of the midgut. 相似文献
97.
Fanconi-Bickel syndrome (FBS, OMIM 227810) is a rare type of glycogen storage disease (GSD). It is caused by homozygous or compound heterozygous mutations within GLUT2, the gene encoding the most important facilitative glucose transporter in hepatocytes, pancreatic beta-cells, enterocytes, and renal tubular cells. To date, 112 patients have been reported in the literature. Most patients have the typical combination of clinical symptoms: hepatomegaly secondary to glycogen accumulation, glucose and galactose intolerance, fasting hypoglycemia, a characteristic tubular nephropathy, and severely stunted growth. In 63 patients, mutation analysis has revealed a total of 34 different GLUT2 mutations with none of them being particularly frequent. No specific therapy is available for FBS patients. Symptomatic treatment is directed towards a stabilization of glucose homeostasis and compensation for renal losses of various solutes. In addition to the clinical and molecular genetic aspects of FBS, this review discusses the pathophysiology of the disease and compares it to recent findings in GLUT2 deficient transgenic animals. An overview is also provided on recently discovered members of the rapidly growing family of facilitative glucose transporters, which are novel candidates for congenital disorders of carbohydrate metabolism. 相似文献
98.
Quinic acid (4) was transformed into phosphitamides 6, 14, and 15, which could be readily linked to 5-O-unprotected cytidine derivative 7; ensuing oxidation of the obtained phosphite triesters with tert-butylhydroperoxide furnished the corresponding phosphate triesters 8, 16, and 17, respectively. Hydrogenolytic debenzylation of the phosphate moiety, base catalysed removal of acetyl protective groups, and basic hydrolysis of the methylester of the quinic acid moiety furnished CMP-Neu5Ac analogues 1-3. In order to measure their inhibition of sialyltransferases, a nonradioactive sialyltransferase assay [employed for (2-6)-sialyltransferase from rat liver (EC 2.4.99.1)] based on reversed-phase HPLC separation of UV-abelled acceptor 20 (p-nitrophenyl glycoside of N-acetyllactosamine) from the UV-labelled product 21 (p-nitrophenyl glycoside of sialyl (2-6)-N-acetyllactosamine) and p-nitrophenylalanine as internal standard was developed. The assay reproduced the reported KM values for CMP-Neu5Ac and N-acetyllactosamine and the Ki values for CDP. 1 and 2 turned out to be potent sialyltransferase inhibitors. © 1998 Rapid Science Ltd 相似文献
99.
Intracellular Localization of Poliovirus Plus- and Minus-Strand RNA Visualized by Strand-Specific Fluorescent In Situ Hybridization 总被引:8,自引:4,他引:4
下载免费PDF全文
![点击此处可从《Journal of virology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Roger Bolten Denise Egger Rainer Gosert Gabriela Schaub Lukas Landmann Kurt Bienz 《Journal of virology》1998,72(11):8578-8585
The time courses of poliovirus plus- and minus-strand RNA synthesis in infected HEp-2 cells were monitored separately, using a quantitative RNase assay. In parallel, viral RNA and proteins were located in situ by confocal microscopy within cells fixed by a protocol determined to retain their native size and shape. Plus- and minus-strand RNAs were visualized by fluorescent in situ hybridization (FISH) with strand-specific riboprobes. The probes were labelled with different fluorochromes to allow for the simultaneous detection of plus- and minus-strand RNA. The FISH experiments showed minus-strand RNA to be present in distinct, regularly sized, round structures throughout the viral replication cycle. Plus-strand RNA was found in the same structures and also in smaller clusters of vesicles. Association of viral RNA with membranes was demonstrated by combining FISH with immunofluorescence (IF) detection of the viral 2B- and 2C-containing P2 proteins, which are known to be markers for virus-induced membranes. At early times postinfection, the virus-induced membranous structures were distributed through most of the cytoplasm, whereas around peak RNA synthesis, both RNA-associated membranous structures migrated to the center of the cell. During this process, the plus- and minus-strand-containing larger structures stayed as recognizable entities, whereas the plus-strand-containing granules coalesced into a juxtanuclear area of membranous vesicles. An involvement of Golgi-derived membranes in the formation of virus-induced vesicles and RNA synthesis early in infection was investigated by IF with 2C- and Golgi-specific antibodies. 相似文献
100.
Pig to human xenotransplantation is considered a possible solution to the
prevailing chronic lack of human donor organs for allotransplantation. The
Galalpha1,3Gal determinant is the major porcine xenogeneic epitope causing
hyperacute rejection following human antibody binding and complement
activation. In order to characterize the tissue distribution of
Galalpha1,3Gal-containing and blood group- type glycosphingolipids in pig,
acid and nonacid glycosphingolipids were isolated from the kidney, small
intestine, spleen, salivary gland, liver, and heart of a single pig
obtained from a semi-inbred strain homozygous at the SLA locus. Glycolipids
were analyzed by thin-layer immunostaining using monoclonal antibodies, and
following ceramide glycanase cleavage as permethylated oligosaccharides by
gas chromatography, gas chromatography-mass spectrometry, and matrix-
assisted laser desorption/ionization mass spectrometry. The kidney
contained large amounts of Galalpha1,3Gal-containing penta- and
hexasaccharides having carbohydrate sequences consistent with the
Galalpha1,3nLc4and Galalpha1,3Lexstructures, respectively. The former
structure was tentatively identified in all organs by GC/MS. The presence
of extended Galalpha1,3Gal-terminated structures in the kidney and heart
was suggested by antibody binding, and GC/MS indicated the presence of a
Galalpha1,3nLc6structure in the heart. The kidney, spleen, and heart
contained blood group H pentaglycosylceramides based on type 1 (H-5-1) and
type 2 (H-5-2) chains, and H hexaglycosylceramides based on the type 4
chain (H-6-4). In the intestine H-5-1 and H-6-4 were expressed, in the
salivary gland H-5-1 and H-5-2, whereas only the H-5-1 structure was
identified in the liver. Blood group A structures were identified in the
salivary gland and the heart by antibody binding and GC/MS, indicating an
organ- specific expression of blood group AH antigens in the pig.
相似文献