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991.
992.
During early pregnancy in the rat, focal adhesions disassemble in uterine luminal epithelial cells at the time of implantation
to facilitate their removal so that the implanting blastocyst can invade into the underlying endometrial decidual cells. This
study investigated the effect of ovarian hormones on the distribution and protein expression of two focal adhesion proteins,
talin and paxillin, in rat uterine luminal and glandular epithelial cells under various hormone regimes. Talin and paxillin
showed a major distributional change between different hormone regimes. Talin and paxillin were highly concentrated along
the basal cell surface of uterine luminal epithelial cells in response to oestrogen treatment. However, this prominent staining
of talin and paxillin was absent and also a corresponding reduction of paxillin expression was demonstrated in response to
progesterone alone or progesterone in combination with oestrogen, which is also observed at the time of implantation. In contrast,
the distribution of talin and paxillin in uterine glandular epithelial cells was localised on the basal cell surface and remained
unchanged in all hormone regimes. Thus, not all focal adhesions are hormonally dependent in the rat uterus; however, the dynamics
of focal adhesion in uterine luminal epithelial cells is tightly regulated by ovarian hormones. In particular, focal adhesion
disassembly in uterine luminal epithelial cells, a key component to establish successful implantation, is predominantly under
the influence of progesterone. 相似文献
993.
Marwen Moussa Vincent Espinasse Jean-Marie Perrier-Cornet Patrick Gervais 《Applied microbiology and biotechnology》2009,85(1):165-174
We investigated the influence of cell hydration on the ability of Saccharomyces cerevisiae CBS 1171 to withstand extreme hydrostatic pressure in order to determine the mechanisms involved in cell resistance. Hydration
conditions were modified in two different ways. We first modulated the chemical potential of water by adding glycerol in cell
suspensions. Another procedure consisted in dehydrating cells aerobically and immersing them in perfluorooctane, an innocuous
hydrophobic liquid used as a pressure-transmitting medium, prior to pressure treatments. This original method made it possible
to transmit isostatic pressure to yeast powders without changing the initial water activity (a
w) level at which cells had been equilibrated. The a
w ranged between 0.11 and 0.99. Pressure treatments were applied at levels of up to 600 MPa for 10 min, 24 h, and 6 days. The
dehydration of cells was found to strongly limit, or even prevent, cell inactivation under pressure. Notably, cells suspended
in a water–glycerol mixture with a
w levels of 0.71 or below were completely protected against all pressure treatments. Moreover, cells dehydrated aerobically
survived for 6 days at 600 MPa even when a
w levels were relatively high (up to 0.94). We highlighted the crucial role of water content in determining cellular damage
under pressure. When water is available in a sufficient amount, high pressure induces membrane permeabilization, causing uncontrolled
mass transfers that could lead to death during a prolonged holding under pressure. Possible mechanisms of membrane permeabilization
are discussed. 相似文献
994.
Susumu Goto Yoshiaki Tsuda Yukihiro Koike Chunlan Lian Yuji Ide 《Ecological Research》2009,24(6):1267-1277
To evaluate the effects of landscape and demographic history on genetic variation in Picea glehnii at a regional scale we have investigated the genetic diversity and genetic differentiation of P. glehnii populations in the Furano region, central Hokkaido, Japan, using seven simple sequence repeat (SSR) markers. We found significant
correlations between elevation and genetic diversity parameters. The value of A
[46] increased and the value of F
IS decreased with increasing elevation, while F
IS values were not significantly different from 0 in any of the populations. Significant recent bottlenecks were detected for
isolated populations at low-elevation sites and for relatively large populations at moderate- and high-elevation sites. Evolutionary
events pre-dating the Holocene should be taken into consideration, as elevational gradients should be with respect to locally
adapted traits such as flowering phenology, However, the palynological data from the Holocene in this region suggest that
the distribution pattern of genetic diversity of P. glehnii detected here may have been influenced by past demographic history related to the elevation shifts in this species’ distribution
associated with climate change during this period. Population differentiation was low, with F
ST and G′ST values of 0.022 and 0.065, respectively. However, genetic boundaries were detected around one swamp population (C13). Therefore,
significant isolation by distance (IBD) was not detected when all populations were considered, but there was significant IBD
when the C13 population was excluded. Information on genetic diversity and genetic differentiation at the regional scale may
be useful for selecting seed sources for afforestation programs for P. glehnii. 相似文献
995.
Cervellati C Franzoni L Squerzanti M Bergamini CM Spinozzi F Mariani P Lanzara V Spisni A 《Amino acids》2009,36(4):633-641
Activation of tissue transglutaminase by calcium involves a conformational change which allows exposition of the active site
to the substrate via movements of domains 3 and 4 that lead to an increase of the inter-domain distance. The inhibitor GTP
counteracts these changes. Here we investigate the possible existence of non-native conformational states still compatible
with the enzyme activity produced by chemical and thermal perturbations. The results indicate that chemical denaturation is
reversible at low guanidine concentrations but irreversible at high concentrations of guanidine. Indeed, at low guanidine
concentrations tissue TG-ase exists in a non-native state which is still affected by the ligands as in the native form. In
contrast, thermal unfolding is always irreversible, with aggregation and protein self-crosslinkage in the presence of calcium.
DSC thermograms of the native protein in the absence of ligands consist of two partly overlapped transitions, which weaken
in the presence of calcium and merge together and strengthen in the presence of GTP. Overall, the present work shows, for
the first time, the reversible denaturation of a TG-ase isoenzyme and suggests the possibility that also in in vivo, the enzyme
may acquire non-native conformations relevant to its patho-physiological functions. 相似文献
996.
Senescence-Accelerated Mouse (SAM) with Special References to Neurodegeneration Models,SAMP8 and SAMP10 Mice 总被引:1,自引:0,他引:1
Toshio Takeda 《Neurochemical research》2009,34(4):639-659
The SAM strains, a group of related inbred strains consisting of senescence-prone inbred strains (SAMP) and senescence-resistant
inbred strains (SAMR), have been successfully developed by selective inbreeding of the AKR/J strain of mice donated by the
Jackson laboratory in 1968. The characteristic feature of aging common to the SAMP and SAMR is accelerated senescence and
normal aging, respectively. Furthermore, SAMP and SAMR strains of mice manifest various pathobiological phenotypes spontaneously.
Among SAMP strains, SAMP8 and SAMP10 mice show age-related behavioral deterioration such as deficits in learning and memory,
emotional disorders (reduced anxiety-like behavior and depressive behavior) and altered circadian rhythm associated with certain
pathological, biochemical and pharmacological changes. Here, the previous and recent literature on SAM mice are reviewed with
an emphasis on SAMP8 and SAMP10 mice. A spontaneous model like SAM with distinct advantages over the gene-modified model is
hoped by investigators to be used more widely as a biogerontological resource to explore the etiopathogenesis of accelerated
senescence and neurodegenerative disorders. 相似文献
997.
Demetrio Boltovskoy Alexander Karatayev Lyubov Burlakova Daniel Cataldo Vadim Karatayev Francisco Sylvester Alejandro Mariñelarena 《Hydrobiologia》2009,636(1):271-284
Since its introduction in South America around 1990, the freshwater Asian mussel Limnoperna fortunei has been shown to strongly interact with several components of the local biota. However, investigation of its ecosystem-wide
effects was hindered by (1) difficulties associated with evaluation of its densities over large spatial scales and (2) scarcity
of pre-invasion environmental data. The present survey overcomes these shortcomings and addresses the question whether Limnoperna’s impact on the ecosystem-wide scale is measurable and significant. On the basis of diver-collected bottom samples, we estimated
the overall density of this mussel in a reservoir (Embalse de Río Tercero, Argentina), where Limnoperna is present since 1998 and analyzed changes in several water-column properties before and after the invasion. The 47 km2 reservoir hosts around 45 billion mussels; at these densities, a volume equivalent to that of this water body can potentially
be filtered by the bivalves every 2–3 days. Data collected regularly since 1996 indicate that after the invasion water transparency
increased, and suspended matter, chlorophyll a, and primary production decreased significantly, with strong changes occurring in the area with highest mussel densities.
Our results indicate that the ecosystem-wide impacts of Limnoperna are generally comparable to those described in Europe and North America for another invasive mussel—Dreissena polymorpha. However, given Limnoperna’s wider tolerance limits, its influence on newly invaded water bodies, potentially including Europe and North America, will
probably be stronger. 相似文献
998.
Diane E. Darlington Chiu-Yueh Hung Jiahua Xie 《Plant Cell, Tissue and Organ Culture》2009,99(2):157-165
Agrobacterium
tumefaciens strain LBA4404 containing the plasmid pBI121, carrying the reporter gene uidA and the kanamycin resistance gene nptII, was used for gene transfer experiments in selenium (Se)-hyperaccumulator Astragalus racemosus. The effects of kanamycin on cell growth and division and acetosyringone on transformation efficiency were evaluated. The
optimal concentration of kanamycin that could effectively inhibit cell growth and division in non-transgenic tissues was 50 mg l−1 and thus all putative transgenic plants were obtained on induction medium containing 50 mg l−1 kanamycin. The verification of transformants was achieved by both histochemical GUS assay and PCR amplification of nptII gene. Southern blot analysis was performed to further confirm that transgene nptII was stably integrated into the A. racemosus genome. A transformation frequency of approximately 10% was achieved using this protocol, but no beneficial effect from the
addition of acetosyringone (50 μM) was observed. This transformation system will be a useful tool for future studies of genes
responsible for Se-accumulation in A. racemosus. 相似文献
999.
Shipan Dai Chhinder Sodhi Selma Cetin Ward Richardson Maria Branca Matthew D. Neal Thomas Prindle Congrong Ma Richard A. Shapiro Bin Li James H.-C. Wang David J. Hackam 《The Journal of biological chemistry》2010,285(7):4995-5002
Toll-like receptor-4 (TLR4) is the receptor for bacterial lipopolysaccharide, yet it may also respond to a variety of endogenous molecules. Necrotizing enterocolitis (NEC) is the leading cause of death from gastrointestinal disease in newborn infants and is characterized by intestinal mucosal destruction and impaired enterocyte migration due to increased TLR4 signaling on enterocytes. The endogenous ligands for TLR4 that lead to impaired enterocyte migration remain unknown. High mobility group box-1 (HMGB1) is a DNA-binding protein that is released from injured cells during inflammation. We thus hypothesize that extracellular HMGB1 inhibits enterocyte migration via activation of TLR4 and sought to define the pathways involved. We now demonstrate that murine and human NEC are associated with increased intestinal HMGB1 expression, that serum HMGB1 is increased in murine NEC, and that HMGB1 inhibits enterocyte migration in vitro and in vivo in a TLR4-dependent manner. This finding was unique to enterocytes as HMGB1 enhanced migration of inflammatory cells in vitro and in vivo. In seeking to understand the mechanisms involved, TLR4-dependent HMGB1 signaling increased RhoA activation in enterocytes, increased phosphorylation of focal adhesion kinase, and increased phosphorylation of cofilin, resulting in increased stress fibers and focal adhesions. Using single cell force traction microscopy, the net effect of HMGB1 signaling was a TLR4-dependent increase in cell force adhesion, accounting for the impaired enterocyte migration. These findings demonstrate a novel pathway by which TLR4 activation by HMGB1 delays mucosal repair and suggest a novel potential therapeutic target in the amelioration of intestinal inflammatory diseases like NEC. 相似文献
1000.
Guangyong Zheng ;Hong Li ;Chuan Wang ;Quanhu Sheng ;Haiwei Fan ;Shaoyou Yang ;Boshu Liu ;Jianliang Dai ;Rong Zeng ;Lu Xie 《Acta biochimica et biophysica Sinica》2009,(4):273-279
With the development of functional genomics research, large-scale proteomics studies are now widespread, presenting significant challenges for data storage, exchange, and analysis. Here we present the Integrated Proteomics Exploring Database (IPED) as a platform for managing proteomics experimental data (both process and result data). IPED is based on the schema of the Proteome Experimental Data Repository (PEDRo), and complies with the General Proteomics Standard (GPS) drafted by the Proteomics Standards Committee of the Human Proteome Organization. In our work, we developed three components for the IPED platform: the IPED client editor, IPED server software, and IPED web interface. The client editor collects experimental data and generates an extensible markup language (XML) data file compliant with PEDRo and GPS; the server software parses the XML data file and loads information into a core database; and the web interface displays experimental results, to provide a convenient graphic representation of data. Given software convenience and data abundance, IPED is a powerful platform for data exchange and presents an important resource for the proteomics community. In its current release, IPED is available at http://www. biosino.org/iped2. 相似文献