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121.
Marjolein Glas H. Bart van den Berg van Saparoea Stephen H. McLaughlin Winfried Roseboom Fan Liu Gregory M. Koningstein Alexander Fish Tanneke den Blaauwen Albert J. R. Heck Luitzen de Jong Wilbert Bitter Iwan J. P. de Esch Joen Luirink 《The Journal of biological chemistry》2015,290(35):21498-21509
Cell division in Escherichia coli involves a set of essential proteins that assembles at midcell to form the so-called divisome. The divisome regulates the invagination of the inner membrane, cell wall synthesis, and inward growth of the outer membrane. One of the divisome proteins, FtsQ, plays a central but enigmatic role in cell division. This protein associates with FtsB and FtsL, which, like FtsQ, are bitopic inner membrane proteins with a large periplasmic domain (denoted FtsQp, FtsBp, and FtsLp) that is indispensable for the function of each protein. Considering the vital nature and accessible location of the FtsQBL complex, it is an attractive target for protein-protein interaction inhibitors intended to block bacterial cell division. In this study, we expressed FtsQp, FtsBp, and FtsLp individually and in combination. Upon co-expression, FtsQp was co-purified with FtsBp and FtsLp from E. coli extracts as a stable trimeric complex. FtsBp was also shown to interact with FtsQp in the absence of FtsLp albeit with lower affinity. Interactions were mapped at the C terminus of the respective domains by site-specific cross-linking. The binding affinity and 1:1:1 stoichiometry of the FtsQpBpLp complex and the FtsQpBp subcomplex were determined in complementary surface plasmon resonance, analytical ultracentrifugation, and native mass spectrometry experiments. 相似文献
122.
123.
Jabari S da Silveira AB de Oliveira EC Neto SG Quint K Neuhuber W Brehmer A 《Histochemistry and cell biology》2011,135(1):47-57
One frequent chronic syndrome of Chagas’ disease is megacolon, an irreversible dilation of a colonic segment. Extensive enteric
neuron loss in the affected segment is regarded as key factor for deficient motility. Here, we assessed the quantitative balance
between cholinergic and nitrergic neurons representing the main limbs of excitatory and inhibitory colonic motor innervation,
respectively. From surgically removed megacolonic segments of four patients, each three myenteric wholemounts (from non-dilated
oral, megacolonic and non-dilated anal parts) was immunohistochemically triple-stained for choline acetyltransferase, neuronal
nitric oxide synthase (NOS) and the panneuronal human neuronal protein Hu C/D. Degenerative changes were most pronounced in
the megacolonic and anal regions, e.g. bulked, honeycomb-like ganglia with few neurons which were partly enlarged or atrophic
or vacuolated. Neuron counts from each 15 ganglia of 12 megacolonic wholemounts were compared with those of 12 age- and region-matched
controls. Extensive neuron loss, mainly in megacolonic and anal wholemounts, was obvious. In all three regions derived from
megacolonic samples, the proportion of NOS-positive neurons (control: 55%) was significantly increased: in non-dilated oral
parts to 61% (p = 0.003), in megacolonic regions to 72% (p < 0.001) and in non-dilated anal regions to 78% (p < 0.001). We suggest the chronic dilation of megacolonic specimens to be due to the preponderance of the nitrergic, inhibitory
input to the intestinal muscle. However, the observed neuronal imbalance was not restricted to the dilated regions: the non-dilated
anal parts may be innervated by ascending, cholinergic axons emerging from less affected, more anally located regions. 相似文献
124.
Biotas from all ecosystems need to respond to factors that determine habitat suitability. These factors originate from different
scales. Effects can be assumed to be hierarchical in the order large-scale geographic > regional > local > small-scale in-habitat
factors. We aimed at the identification of general patterns by comparisons between ecosystems (forest floor snails, hololimnic
stream macroinvertebrates) and across scales, and include potential seasonal effects. Sampling sites displayed signs of naturalness,
such as high levels of deadwood accumulation in the forests, or a lack of artificial stream bed fixation plus a “good” to
“high” score for the assemblage-derived Multimetric Index (MMI) in the streams. Terrestrial and aquatic assemblages of non-emergent
taxa fluctuated independent of seasonal effects. They differed in their relative correlation with environmental matrices with
quasi-concentric effects in forests, and longitudinal effects in streams. Large-scale factors, namely geographic position,
strongly influenced assemblage turnover, but the effect is based on a high covariation between geographic position and environmental
factors. We thus extracted variables that best explained species turnover after correcting for spatio-temporal effects. The
terrestrial community assembling was habitat-based and mainly responded to soil acidification, distance to disturbances, and
regional scale deforestation and deciduous/mixed forest cover. The stream assemblages were structured by regional pasture
cover, organic pollution, regional deciduous forest cover and microlithal cover. Apparently, community assembly occurs along
with changes in regional forest cover and the transport of nutrients and matter that can originate from a distance, irrespective
of ecosystem and assumed “naturalness”. 相似文献
125.
126.
Frosch Christiane Haase Peter Nowak Carsten 《European Journal of Wildlife Research》2011,57(3):679-682
Noninvasive genetic techniques have become indispensible tools in wildlife conservation and management. Here, we report the
development of the first set of microsatellite markers for the Eurasian beaver (Castor fiber). All 15 loci show considerable variation within the sampled region in southwestern Germany, with number of alleles ranging
from two to six alleles per locus. A comparison between tissue and hair samples revealed that amplification success was only
slightly lower for hair samples, making their use in noninvasive monitoring feasible. Despite some evidence for false alleles
and allelic dropout, 77% of all loci were genotyped successfully among all hair samples and loci tested. The developed markers
will be used for subspecies differentiation and reconstruction of dispersal routes, following reintroductions in Central Europe. 相似文献
127.
Li Z Vizeacoumar FJ Bahr S Li J Warringer J Vizeacoumar FS Min R Vandersluis B Bellay J Devit M Fleming JA Stephens A Haase J Lin ZY Baryshnikova A Lu H Yan Z Jin K Barker S Datti A Giaever G Nislow C Bulawa C Myers CL Costanzo M Gingras AC Zhang Z Blomberg A Bloom K Andrews B Boone C 《Nature biotechnology》2011,29(4):361-367
Conditional temperature-sensitive (ts) mutations are valuable reagents for studying essential genes in the yeast Saccharomyces cerevisiae. We constructed 787 ts strains, covering 497 (~45%) of the 1,101 essential yeast genes, with ~30% of the genes represented by multiple alleles. All of the alleles are integrated into their native genomic locus in the S288C common reference strain and are linked to a kanMX selectable marker, allowing further genetic manipulation by synthetic genetic array (SGA)-based, high-throughput methods. We show two such manipulations: barcoding of 440 strains, which enables chemical-genetic suppression analysis, and the construction of arrays of strains carrying different fluorescent markers of subcellular structure, which enables quantitative analysis of phenotypes using high-content screening. Quantitative analysis of a GFP-tubulin marker identified roles for cohesin and condensin genes in spindle disassembly. This mutant collection should facilitate a wide range of systematic studies aimed at understanding the functions of essential genes. 相似文献
128.
129.
A Hedrych-Ozimina K Behrendt Z Hao R Pofahl D Ussath R Knaup T Krieg I Haase 《Cell death and differentiation》2011,18(1):155-163
FAS/CD95/Apo-1 is a ubiquitously expressed cell-surface receptor involved in the initiation of programmed cell death. Its function in epidermal keratinocytes has been incompletely defined. Available evidence from in vitro studies points to important roles of Fas in the pathogenesis of contact dermatitis and in keratinocyte apoptosis induced by ultraviolet light. To define functions of Fas in the epidermis in vivo, we have generated mice with epidermis-specific deletion of the fas gene and tested its requirement for 2,4-dinitrofluorobenzene-induced contact dermatitis and for ultraviolet light B (UVB)-induced keratinocyte apoptosis. We report here our unexpected finding that keratinocyte apoptosis induced by both a contact allergen and UVB irradiation was significantly enhanced in Fas-negative epidermis. Expression of Fas by epidermal keratinocytes was neither necessary for the normal development of contact hypersensitivity of the skin, nor required for keratinocyte apoptosis following UVB irradiation. Our study results thus show that in the epidermis in vivo Fas exerts antiapoptotic effects that outweigh its proapoptotic role in contact hypersensitivity responses of the skin and in the tissue response of the epidermis to UVB irradiation. 相似文献
130.
Becker SL Sieto B Silué KD Adjossan L Koné S Hatz C Kern WV N'Goran EK Utzinger J 《PLoS neglected tropical diseases》2011,5(8):e1292