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971.
Nino Asatiani Tamar Kartvelishvili Marina Abuladze Lali Asanishvili Nelly Sapojnikova 《Biological trace element research》2011,142(3):388-397
The changes in glutathione-dependent cycle enzymes and catalase activities under Cr(VI)-induced oxidative stress were investigated
in two distinct cell lines: L-41−human epithelial-like cells and HLF−fetal human diploid lung fibroblasts, which differ in
tissue origin, proliferation, and antioxidant enzymes activities. The chromium concentrations from 1 to 5 μM cause nontoxic
effects and activate antioxidant enzymes to overcome oxidative stress. In spite of some differences in the endogenous antioxidant
activities, both cell lines reveal the same range of toxic concentrations (20–30 μM). The irreversible inhibition of glutathione-dependent
antioxidant enzymes develops under toxic concentrations and serves as a marker of toxicity. The endogenous antioxidant activity
influences time-dependent expression of Cr(VI) toxicity and the dynamics of antioxidant enzymes activity under nontoxic conditions.
The cell antioxidant defense system is an important marker of the cell adaptive capacity under nontoxic and toxic conditions. 相似文献
972.
Park SJ Park BJ Jung MY Kim SJ Chae JC Roh Y Forwick M Yoon HI Rhee SK 《Microbial ecology》2011,62(3):537-548
Increases in global temperatures have been shown to enhance glacier melting in the Arctic region. Here, we have evaluated
the effects of meltwater runoff on the microbial communities of coastal marine sediment located along a transect of Temelfjorden,
in Svalbard. As close to the glacier front, the sediment properties were clearly influenced by deglaciation. Denaturing gradient
gel electrophoresis profiles showed that the sediment microbial communities of the stations of glacier front (stations 188–178)
were distinguishable from that of outer fjord region (station 176). Canonical correspondence analysis indicated that total
carbon and calcium carbonate in sediment and chlorophyll a in bottom water were key factors driving the change of microbial
communities. Analysis of 16S rRNA gene clone libraries suggested that microbial diversity was higher within the glacier–proximal
zone (station 188) directly affected by the runoffs than in the outer fjord region. While the crenarchaeotal group I.1a dominated
at station 176 (62%), Marine Benthic Group-B and other Crenarchaeota groups were proportionally abundant. With regard to the
bacterial community, alpha-Proteobacteria and Flavobacteria lineages prevailed (60%) at station 188, whereas delta-Proteobacteria (largely sulfate-reducers) predominated (32%) at station 176. Considering no clone sequences related to sulfate-reducers,
station 188 may be more oxic compared to station 176. The distance-wise compositional variation in the microbial communities
is attributable to their adaptations to the sediment environments which are differentially affected by melting glaciers. 相似文献
973.
974.
We evaluated the changes in CD4 + CD25high regulatory T (Treg) cells and FOXP3 mRNA expression in patients with advanced esophageal cancer as well as its clinical significance.
For this purpose, the frequencies of peripheral blood Treg cells in 68 patients with advanced esophageal cancer and 40 healthy
controls were determined by flow cytometry, and FOXP3 mRNA expression in Treg cells of 40 patients was determined by RT–PCR.
The data show that Treg cell numbers were significantly higher (P < 0.01) in esophageal cancer patients (1.82 ± 0.54% of CD4 + T cells) as compared with healthy controls (1.52 ± 0.70% of
CD4+ T cells). Treg cell numbers in the patients were significantly higher (P < 0.05) before chemotherapy (1.82 ± 0.54% of CD4 + T cells) than after chemotherapy (1.66 ± 0.58% of CD4 + T cells). Expression
of the FOXP3 mRNA in the patients was significantly lower (P < 0.05) after chemotherapy (0.266 ± 0.028% of CD4 + T cells) than before chemotherapy (0.318 ± 0.027% of CD4 + T cells).
It was, therefore, concluded that Treg cell numbers as well as FOXP3 mRNA expression in advanced esophageal cancer patients
were significantly decreased after chemotherapy. Notably, FOXP3 gene may thus be involved in regulating the numbers and function
of Treg cells in advanced esophageal cancer patients receiving chemotherapy. 相似文献
975.
Guillaume Gayet Cyril Eraud Maurice Benmergui Joël Broyer François Mesleard Hervé Fritz Matthieu Guillemain 《European Journal of Wildlife Research》2011,57(5):1051-1056
A number of native and exotic animal species show dramatic population increases in terms of both numbers and geographic range.
Understanding the habitat selection processes behind such increases is crucial to implement adequate management measures.
Mute swan (Cygnus olor) populations have experienced a tremendous demographic and geographic expansion in Western Europe during the twentieth century,
colonizing a wide variety of aquatic habitats. We aimed at assessing how swans select nesting sites during the pre-laying
and laying periods on medium to large fishponds (from 10 to 50 ha) in Eastern France, while accounting for detectability biases
and testing for the effects of fishpond spatial configuration, vegetation resources, human disturbance and habitat management.
Our results demonstrate that the mute swan is a non-selective species regarding its nesting habitat among such fishponds,
using these independently from the parameters considered although fishpond characteristics varied. Although mute swan is one
of the least cryptic Anatidae, owing to its white colour and large size, detection of breeding pairs remained imperfect for
each over several sampling occasions. However, because we repeated the sampling sessions, detection of swan pairs by the end
of the monitoring period was as high as 0.94. These results are consistent with previous assertions that the mute swan is
a species of high ecological plasticity, which may partly explain its recent colonization rates. Given that even swan breeding
events were imperfectly detected on each occasion, we highlight the fact that most studies of breeding ducks (which are more
cryptic) would be considerably improved by better considering detection biases. 相似文献
976.
Mai Kanke Kohei Nishimura Masato Kanemaki Tatsuo Kakimoto Tatsuro S Takahashi Takuro Nakagawa Hisao Masukata 《BMC cell biology》2011,12(1):8
Background
Inducible inactivation of a protein is a powerful approach for analysis of its function within cells. Fission yeast is a useful model for studying the fundamental mechanisms such as chromosome maintenance and cell cycle. However, previously published strategies for protein-depletion are successful only for some proteins in some specific conditions and still do not achieve efficient depletion to cause acute phenotypes such as immediate cell cycle arrest. The aim of this work was to construct a useful and powerful protein-depletion system in Shizosaccaromyces pombe. 相似文献977.
Matthew J Christmas Julia C Jones Anna Olsson Ola Wallerman Ignas Bunikis Marcin Kierczak Valentina Peona Kaitlyn M Whitley Tuuli Larva Alexander Suh Nicole E Miller-Struttmann Jennifer C Geib Matthew T Webster 《Molecular biology and evolution》2021,38(8):3126
Evidence is accumulating that gene flow commonly occurs between recently diverged species, despite the existence of barriers to gene flow in their genomes. However, we still know little about what regions of the genome become barriers to gene flow and how such barriers form. Here, we compare genetic differentiation across the genomes of bumblebee species living in sympatry and allopatry to reveal the potential impact of gene flow during species divergence and uncover genetic barrier loci. We first compared the genomes of the alpine bumblebee Bombus sylvicola and a previously unidentified sister species living in sympatry in the Rocky Mountains, revealing prominent islands of elevated genetic divergence in the genome that colocalize with centromeres and regions of low recombination. This same pattern is observed between the genomes of another pair of closely related species living in allopatry (B. bifarius and B. vancouverensis). Strikingly however, the genomic islands exhibit significantly elevated absolute divergence (dXY) in the sympatric, but not the allopatric, comparison indicating that they contain loci that have acted as barriers to historical gene flow in sympatry. Our results suggest that intrinsic barriers to gene flow between species may often accumulate in regions of low recombination and near centromeres through processes such as genetic hitchhiking, and that divergence in these regions is accentuated in the presence of gene flow. 相似文献
978.
Jeffrey A. Pfefferkorn Meihua Tu Kevin J. Filipski Angel Guzman-Perez Jianwei Bian Gary E. Aspnes Matthew F. Sammons Wei Song Jian-Cheng Li Christopher S. Jones Leena Patel Tim Rasmusson Dongxiang Zeng Kapil Karki Michael Hamilton Richard Hank Karen Atkinson John Litchfield Robert Aiello Levenia Baker Alan Robertson 《Bioorganic & medicinal chemistry letters》2012,22(23):7100-7105
Glucokinase activators represent a promising potential treatment for patients with Type 2 diabetes. Herein, we report the identification and optimization of a series of novel indazole and pyrazolopyridine based activators leading to the identification of 4-(6-(azetidine-1-carbonyl)-5-fluoropyridin-3-yloxy)-2-ethyl-N-(5-methylpyrazin-2-yl)-2H-indazole-6-carboxamide (42) as a potent activator with favorable preclinical pharmacokinetic properties and in vivo efficacy. 相似文献
979.
Background
Community-based organizations (CBOs) are important stakeholders in health systems and are increasingly called upon to use research evidence to inform their advocacy, program planning, and service delivery efforts. CBOs increasingly turn to community-based research (CBR) given its participatory focus and emphasis on linking research to action. In order to further facilitate the use of research evidence by CBOs, we have developed a strategy for community-based knowledge transfer and exchange (KTE) that helps CBOs more effectively link research evidence to action. We developed the strategy by: outlining the primary characteristics of CBOs and why they are important stakeholders in health systems; describing the concepts and methods for CBR and for KTE; comparing the efforts of CBR to link research evidence to action to those discussed in the KTE literature; and using the comparison to develop a framework for community-based KTE that builds on both the strengths of CBR and existing KTE frameworks.Discussion
We find that CBR is particularly effective at fostering a climate for using research evidence and producing research evidence relevant to CBOs through community participation. However, CBOs are not always as engaged in activities to link research evidence to action on a larger scale or to evaluate these efforts. Therefore, our strategy for community-based KTE focuses on: an expanded model of 'linkage and exchange' (i.e., producers and users of researchers engaging in a process of asking and answering questions together); a greater emphasis on both producing and disseminating systematic reviews that address topics of interest to CBOs; developing a large-scale evidence service consisting of both 'push' efforts and efforts to facilitate 'pull' that highlight actionable messages from community relevant systematic reviews in a user-friendly way; and rigorous evaluations of efforts for linking research evidence to action.Summary
Through this type of strategy, use of research evidence for CBO advocacy, program planning, and service delivery efforts can be better facilitated and continually refined through ongoing evaluations of its impact.980.
Chien-Li Chiu Jen-Leih Wu Guor-Mour Her Yi-Li Chou Jiann-Ruey Hong 《Apoptosis : an international journal on programmed cell death》2010,15(6):653-668
Aquatic birnavirus induces post-apoptotic necrotic cell death via a newly synthesized protein-dependent pathway. However,
the involvement of viral genome-encoded protein(s) in this death process remains unknown. In the present study, we demonstrated
that the submajor capsid protein, VP3, up-regulates the pro-apoptotic protein, Bad, in fish and mouse cells. Western blot
analysis revealed that VP3 was expressed in CHSE-214 cells at 4 h post-infection (pi), indicating an early role during viral replication. We cloned
the VP3 gene and tested its function in fish and mouse cells; VP3 overexpression induced apoptotic cell death by TUNEL assay. In
addition, it up-regulated Bad gene expression in zebrafish ZLE cells by threefold at 12 h post-transfection (pt) and in mouse NIH3T3 cells by tenfold at
24 h pt. VP3 up-regulation of Bad expression altered mitochondria function, inducing mitochondrial membrane potential (MMP)
loss and activating initiator caspase-9 and effector caspase-3. Furthermore, reduced Bad expression (65% reduction), MMP loss
(up to 40%), and enhanced cell viability (up to 60%) upon expression of VP3 antisense RNA in CHSE-214 cells at 24 h post-IPNV
infection was observed. Finally, overexpression of the anti-apoptotic gene, zfBcl-xL, reduced VP3-induced apoptotic cell death and caspase-3 activation at 24 h in fish cells. Taken together, these results suggest
that aquatic birnavirus VP3 induces apoptosis via up-regulation of Bad expression and mitochondrial disruption, which activates a downstream caspase-3-mediated death pathway that is blocked by
zfBcl-xL. 相似文献