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991.
The macrophytes Fucus serratus and Zostera marina form similar substrates for associated flora and fauna in shallow waters in Norway. While F. serratus forms a more or less continuous belt on rocky substrate along the coast, Z. marina forms disjunct populations on sandy or muddy bottoms. This study focused on the organisms associated with these two macrophytes in two localities in the Skagerrak region. In total, 130 taxa of epiphytic organisms were identified: 22 green algae, 41 red algae, 32 brown algae, eight diatoms and 27 sessile animals. One hundred and twenty-seven taxa of mobile macrofauna were registered. The dominant group was crustaceans, with amphipods as the order containing most species. Many species of both plants and animals preferred one or the other habitat. It is concluded that coastal macrophyte systems have high species diversity. 相似文献
992.
Dmitri V Krysko Tom Vanden Berghe Katharina D'Herde Peter Vandenabeele 《Methods (San Diego, Calif.)》2008,44(3):205-221
Three major morphologies of cell death have been described: apoptosis (type I), cell death associated with autophagy (type II) and necrosis (type III). Apoptosis and cell death associated with autophagy can be distinguished by certain biochemical events. However, necrosis is characterized mostly in negative terms by the absence of caspase activation, cytochrome c release and DNA oligonucleosomal fragmentation. A particular difficulty in defining necrosis is that in the absence of phagocytosis apoptotic cells become secondary necrotic cells with many morphological features of primary necrosis. In this review, we present a selection of techniques that can be used to identify necrosis and to discriminate it from apoptosis. These techniques rely on the following cell death parameters: (1) morphology (time-lapse and transmission electron microscopy and flow fluorocytometry); (2) cell surface markers (phosphatidylserine exposure versus membrane permeability by flow fluorocytometry); (3) intracellular markers (oligonucleosomal DNA fragmentation by flow fluorocytometry, caspase activation, Bid cleavage and cytochrome c release by western blotting); (4) release of extracellular markers in the supernatant (caspases, HMGB-1 and cytokeratin 18). Finally, we report on methods that can be used to examine interactions between dying cells and phagocytes. We illustrate a quantitative method for detecting phagocytosis of dying cells by flow fluorocytometry. We also describe a recently developed approach based on the use of fluid phase tracers and different kind of microscopy, transmission electron and fluorescence microscopy, to characterize the mechanisms used by phagocytes to internalize dying cells. 相似文献
993.
We studied the serum bactericidal activity (SBA) of moxifloxacin and levofloxacin against common pathogens associated with complicated intra-abdominal infections. Ten healthy volunteers received a single dose of moxifloxacin (400 mg) and levofloxacin (750 mg) and serum samples were collected at 2, 4, 8, 12, and 24h after the dose of each drug. Bactericidal titers in serum over time were determined for aerobic gram-negative bacilli (Escherichia coli, Klebseilla pneumoniae, and Enterobacter cloacae) and anaerobic bacteria (Bacteroides fragilis, Bacteroides thetaiotaomicron, Prevotella bivia, and Finegoldia magna). Both fluoroquinolones provided rapid (2h) attainment and prolonged (24h) SBA (titers > or = 1:8) against each of the aerobic bacilli studied. SBA was observed for at least 12h against B. fragilis strains with MICs < or = 2 microg/ml to moxifloxacin and < or = 4 microg/ml to levofloxacin. Prolonged (12h) SBA (titers > or = 1:2) was also observed against isolates of B. thetaiotaomicron, P. bivia, and F. magna with moxifloxacin < or = MICs 2 microg/ml. 相似文献
994.
Patnaik D Jun Xian Glicksman MA Cuny GD Stein RL Higgins JM 《Journal of biomolecular screening》2008,13(10):1025-1034
Haspin/Gsg2 is a kinase that phosphorylates histone H3 at Thr-3 (H3T3ph) during mitosis. Its depletion by RNA interference results in failure of chromosome alignment and a block in mitosis. Haspin, therefore, is a novel target for development of antimitotic agents. We report the development of a high-throughput time-resolved fluorescence resonance energy transfer (TR-FRET) kinase assay for haspin. Histone H3 peptide was used as a substrate, and a europium-labeled H3T3ph phosphospecific monoclonal antibody was used to detect phosphorylation. A library of 137632 small molecules was screened at K(m) concentrations of ATP and peptide to allow identification of diverse inhibitor types. Reconfirmation of hits and IC( 50) determinations were carried out with the TR-FRET assay and by a radiometric assay using recombinant histone H3 as the substrate. A preliminary assessment of specificity was made by testing inhibition of 2 unrelated kinases. EC( 50) values in cells were determined using a cell-based ELISA of H3T3ph. Five compounds were selected as leads based on potency and chemical structure considerations. These leads form the basis for the development of specific inhibitors of haspin that will have clear utility in basic research and possible use as starting points for development of antimitotic anticancer therapeutics. 相似文献
995.
To reveal mechanisms of DNA damage checkpoint initiation, we structurally and biochemically analyzed DisA, a protein that controls a Bacillus subtilis sporulation checkpoint in response to DNA double-strand breaks. We find that DisA forms a large octamer that consists of an array of an uncharacterized type of nucleotide-binding domain along with two DNA-binding regions related to the Holliday junction recognition protein RuvA. Remarkably, the nucleotide-binding domains possess diadenylate cyclase activity. The resulting cyclic diadenosine phosphate, c-di-AMP, is reminiscent but distinct from c-di-GMP, an emerging prokaryotic regulator of complex cellular processes. Diadenylate cyclase activity is unaffected by linear DNA or DNA ends but strongly suppressed by branched nucleic acids such as Holliday junctions. Our data indicate that DisA signals DNA structures that interfere with chromosome segregation via c-di-AMP. Identification of the diadenylate cyclase domain in other eubacterial and archaeal proteins implies a more general role for c-di-AMP in prokaryotes. 相似文献
996.
Krysko DV Diez-Fraile A Criel G Svistunov AA Vandenabeele P D'Herde K 《Apoptosis : an international journal on programmed cell death》2008,13(9):1065-1087
The vertebrate ovary is an extremely dynamic organ in which excessive or defective follicles are rapidly and effectively eliminated
early in ontogeny and thereafter continuously throughout reproductive life. More than 99% of follicles disappear, primarily
due to apoptosis of granulosa cells, and only a minute fraction of the surviving follicles successfully complete the path
to ovulation. The balance between signals for cell death and survival determines the destiny of the follicles. An abnormally
high rate of cell death followed by atresia can negatively affect fertility and eventually lead irreversibly to premature
ovarian failure. In this review we provide a short overview of the role of programmed cell death in prenatal differentiation
of the primordial germ cells and in postnatal folliculogenesis. We also discuss the issue of neo-oogenesis. Next, we highlight
molecules involved in regulation of granulosa cell apoptosis. We further discuss the potential use of scores for apoptosis
in granulosa cells and characteristics of follicular fluid as prognostic markers for predicting the outcome of assisted reproduction.
Potential therapeutic strategies for combating premature ovarian failure are also addressed. 相似文献
997.
The Generic Model Organism Database (GMOD) initiative provides species-agnostic data models and software tools for representing
curated model organism data. Here we describe GMODWeb, a GMOD project designed to speed the development of model organism
database (MOD) websites. Sites created with GMODWeb provide integration with other GMOD tools and allow users to browse and
search through a variety of data types. GMODWeb was built using the open source Turnkey web framework and is available from
. 相似文献
998.
Blm10 is bound to the yeast proteasome core particle, a crucial protease of eukaryotic cells [corrected]. Two gates, at both ends of the CP, control the access of protein substrates to the catalytic cavity of the CP. Normally, substrate access is auto-inhibited by a closed gate conformation unless regulatory complexes are bound to the CP and translocate protein substrates in an ATP-dependent manner. Here, we provide evidence that Blm10 recognizes pre-activated open gate CPs, which are assumed to exist in an equilibrium with inactive closed gate CP. Consequently, single-capped Blm10-CP shows peptide hydrolysis activity. Under conditions of disturbed CP assembly, as well as in open gate mutants, pre-activated CP or constitutively active CP, respectively, prevail. Then, Blm10 sequesters disordered and open gate CP by forming double-capped Blm10(2)-CP in which peptide hydrolysis activity is repressed. We conclude that Blm10 distinguishes between gate conformations and regulates the activation of CP. 相似文献
999.
Stein LD 《Nature reviews. Genetics》2008,9(9):678-688
Biology is an information-driven science. Large-scale data sets from genomics, physiology, population genetics and imaging are driving research at a dizzying rate. Simultaneously, interdisciplinary collaborations among experimental biologists, theorists, statisticians and computer scientists have become the key to making effective use of these data sets. However, too many biologists have trouble accessing and using these electronic data sets and tools effectively. A 'cyberinfrastructure' is a combination of databases, network protocols and computational services that brings people, information and computational tools together to perform science in this information-driven world. This article reviews the components of a biological cyberinfrastructure, discusses current and pending implementations, and notes the many challenges that lie ahead. 相似文献
1000.