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991.
Fabienne Jung Klaas Enno Stephan Heiko Backes Rosalyn Moran Markus Gramer Tetsuya Kumagai Rudolf Graf Heike Endepols Marc Tittgemeyer 《PloS one》2013,8(4)
Detecting sudden environmental changes is crucial for the survival of humans and animals. In the human auditory system the mismatch negativity (MMN), a component of auditory evoked potentials (AEPs), reflects the violation of predictable stimulus regularities, established by the previous auditory sequence. Given the considerable potentiality of the MMN for clinical applications, establishing valid animal models that allow for detailed investigation of its neurophysiological mechanisms is important. Rodent studies, so far almost exclusively under anesthesia, have not provided decisive evidence whether an MMN analogue exists in rats. This may be due to several factors, including the effect of anesthesia. We therefore used epidural recordings in awake black hooded rats, from two auditory cortical areas in both hemispheres, and with bandpass filtered noise stimuli that were optimized in frequency and duration for eliciting MMN in rats. Using a classical oddball paradigm with frequency deviants, we detected mismatch responses at all four electrodes in primary and secondary auditory cortex, with morphological and functional properties similar to those known in humans, i.e., large amplitude biphasic differences that increased in amplitude with decreasing deviant probability. These mismatch responses significantly diminished in a control condition that removed the predictive context while controlling for presentation rate of the deviants. While our present study does not allow for disambiguating precisely the relative contribution of adaptation and prediction error processing to the observed mismatch responses, it demonstrates that MMN-like potentials can be obtained in awake and unrestrained rats. 相似文献
992.
Ulla Renne Martina Langhammer Julia Brenmoehl Christina Walz Anja Zeissler Armin Tuchscherer Marion Piechotta Rudolf J. Wiesner Maximilian Bielohuby Andreas Hoeflich 《PloS one》2013,8(11)
Aims/Hypothesis
Visceral obesity holds a central position in the concept of the metabolic syndrome characterized by glucose intolerance in humans. However, until now it is unclear if obesity by itself is responsible for the development of glucose intolerance.Methods
We have used a novel polygenic mouse model characterized by genetically fixed obesity (DU6) and addressed age- and high fat diet-dependent glucose tolerance.Results
Phenotype selection over 146 generations increased body weight by about 2.7-fold in male 12-week DU6 mice (P<0.0001) if compared to unselected controls (Fzt:DU). Absolute epididymal fat mass was particularly responsive to weight selection and increased by more than 5-fold (P<0.0001) in male DU6 mice. At an age of 6 weeks DU6 mice consumed about twice as much food if compared to unselected controls (P<0.001). Absolute food consumption was higher at all time points measured in DU6 mice than in Fzt:DU mice. Between 6 and 12 weeks of age, absolute food intake was reduced by 15% in DU6 mice (P<0.001) but not in Fzt:DU mice. In both mouse lines feeding of the high fat diet elevated body mass if compared to the control diet (P<0.05). In contrast to controls, DU6 mice did not display high fat diet-induced increases of epididymal and renal fat. Control mice progressively developed glucose intolerance with advancing age and even more in response to the high fat diet. In contrast, obese DU6 mice did neither develop a glucose intolerant phenotype with progressive age nor when challenged with a high fat diet.Conclusions/Interpretation
Our results from a polygenic mouse model demonstrate that genetically pre-determined and life-long obesity is no precondition of glucose intolerance later in life. 相似文献993.
Ines S. Jaeger Ines Kretzschmar Jana Körner Armin A. Weiser Carsten C. Mahrenholz Ajish Potty Katerina Kourentzi Richard C. Willson Rudolf Volkmer Robert Preissner 《Journal of molecular recognition : JMR》2013,26(1):23-31
To perform their various functions, protein surfaces often have to interact with each other in a specific way. Usually, only parts of a protein are accessible and can act as binding sites. Because proteins consist of polypeptide chains that fold into complex three‐dimensional shapes, binding sites can be divided into two different types: linear sites that follow the primary amino acid sequence and discontinuous binding sites, which are made up of short peptide fragments that are adjacent in spatial proximity. Such discontinuous binding sites dominate protein–protein interactions, but are difficult to identify. To meet this challenge, we combined a computational, structure‐based approach and an experimental, high‐throughput method. SUPERFICIAL is a program that uses protein structures as input and generates peptide libraries to represent the protein's surface. A large number of the predicted peptides can be simultaneously synthesised applying the SPOT technology. The results of a binding assay subsequently help to elucidate protein–protein interactions; the approach is applicable to any kind of protein. The crystal structure of the complex of hen egg lysozyme with the well‐characterised murine IgG1 antibody HyHEL‐5 is available, and the complex is known to have a discontinuous binding site. Using SUPERFICIAL, the entire surface of lysozyme was translated into a peptide library that was synthesised on a cellulose membrane using the SPOT technology and tested against the HyHEL‐5 antibody. In this way, it was possible to identify two peptides (longest common sequence and peptide 19) that represented the discontinuous epitope of lysozyme. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
994.
995.
Claudia?Rudolf von RohrEmail author Judith?M.?Burkart Carel?P.?van?Schaik 《Biology & philosophy》2011,26(1):1-30
Moral behaviour, based on social norms, is commonly regarded as a hallmark of humans. Hitherto, humans are perceived to be
the only species possessing social norms and to engage in moral behaviour. There is anecdotal evidence suggesting their presence
in chimpanzees, but systematic studies are lacking. Here, we examine the evolution of human social norms and their underlying
psychological mechanisms. For this, we distinguish between conventions, cultural social norms and universal social norms.
We aim at exploring whether chimpanzees possess evolutionary precursors of universal social norms seen in humans. Chimpanzees
exhibit important preconditions for their presence and enforcement: tolerant societies, well-developed social-cognitive skills
and empathetic competence. Here, we develop a theoretical framework for recognizing different functional levels of social
norms and distinguish them from mere statistical behavioural regularities. Quasi social norms are found where animals behave
functionally moral without having moral emotions. In proto social norms, moral emotions might be present but cannot be collectivized
due to the absence of a uniquely human psychological trait, i.e. shared intentionality. Human social norms, whether they are
universal or cultural, involve moral emotions and are collectivized. We will discuss behaviours in chimpanzees that represent
potential evolutionary precursors of human universal social norms, with special focus on social interactions involving infants.
We argue that chimpanzee infants occupy a special status within their communities and propose that tolerance towards them
might represent a proto social norm. Finally, we discuss possible ways to test this theoretical framework. 相似文献
996.
Regulatory and metabolic network of rhamnolipid biosynthesis: Traditional and advanced engineering towards biotechnological production 总被引:1,自引:0,他引:1
During the last decade, the demand for economical and sustainable bioprocesses replacing petrochemical-derived products has
significantly increased. Rhamnolipids are interesting biosurfactants that might possess a broad industrial application range.
However, despite of 60 years of research in the area of rhamnolipid production, the economic feasibility of these glycolipids
is pending. Although the biosynthesis and regulatory network are in a big part known, the actual incidents on the cellular
and process level during bioreactor cultivation are not mastered. Traditional engineering by random and targeted genetic alteration,
process design, and recombinant strategies did not succeed by now. For enhanced process development, there is an urgent need
of in-depth information about the rhamnolipid production regulation during bioreactor cultivation to design knowledge-based
genetic and process engineering strategies. Rhamnolipids are structurally comparable, simple secondary metabolites and thus
have the potential to become instrumental in future secondary metabolite engineering by systems biotechnology. This review
summarizes current knowledge about the regulatory and metabolic network of rhamnolipid synthesis and discusses traditional
and advanced engineering strategies performed for rhamnolipid production improvement focusing on Pseudomonas aeruginosa. Finally, the opportunities of applying the systems biotechnology toolbox on the whole-cell biocatalyst and bioprocess level
for further rhamnolipid production optimization are discussed. 相似文献
997.
Abd-El-Karem Y Elbers T Reichelt R Steinbüchel A 《Applied microbiology and biotechnology》2011,89(4):1177-1192
Sinorhizobium meliloti infects leguminous plants resulting in a nitrogen-fixing symbiosis. Free living cells accumulate poly(3-hydroxybutyrate)
(PHB) as carbon and energy source under imbalanced growth conditions. The cphA1
7120 gene encoding a cyanophycin (CGP) synthetase of Anabaena sp. PCC7120 in plasmids pVLT31::cphA1
7120 and pBBR1MCS-3::cphA1
7120 was expressed in the wild-type S. meliloti 1021 and in a phbC-negative mutant generated in this study. Expression of cphA1
7120 and accumulation of CGP in cells were studied in various media. Yeast mannitol broth (YMB) and pBBR1MCS-3::cphA1
7120 yielded the highest CGP contents in both S. meliloti 1021 strains. Supplying the YMB medium with isopropyl-β-D-thiogalactopyranoside, aspartic acid, and arginine enhanced CGP
contents about 2.5- and 2.8-fold in S. meliloti 1021 (pBBR1MCS-3::cphA1
7120) and S. meliloti 1021 phbCΩKm (pBBR1MCS-3::cphA1
7120), respectively. Varying the nitrogen-to-carbon ratio in the medium enhanced the CGP content further to 43.8% (w/w) of cell dry weight (CDW) in recombinant cells of S. meliloti 1021 phbCΩKm (pBBR1MCS-3::cphA1
7120). Cells of S. meliloti 1021 (pBBR1MCS-3::cphA1
7120) accumulated CGP up to 39.6% in addition to 12.1% PHB (w/w, of CDW). CGP from the S. meliloti strains consisted of equimolar amounts of aspartic acid and arginine and contained no other amino acids even if the medium
was supplemented with glutamic acid, citrulline, ornithine, or lysine. CGP isolated from cells of S. meliloti 1021 (pBBR1MCS-3::cphA1
7120) and S. meliloti 1021 phbCΩKm (pBBR1MCS-3::cphA1
7120) exhibited average molecular weights between 20 and 25 kDa, whereas CGP isolated from Escherichia coli S17-1 (pBBR1MCS-3::cphA1
7120) exhibited average molecular weight between 22 and 30 kDa. Co-expression of cyanophycinase from Anabaena sp. PCC7120 encoded by cphB1
7120 in cphA1
7120-positive E. coli S17-1, S. meliloti 1021, and its phbC-negative mutant gave cyanophycinase activities in crude extracts, and no CGP granules occurred. A higher PHB content in S. meliloti 1021 (pBBR1MCS-3::cphB1
7120::cphA1
7120) in comparison to the control indicated that the cells used CGP degradation product (β-aspartate-arginine dipeptide) to fuel
PHB biosynthesis. 相似文献
998.
Gaurav Vaidya Rudolf Meier 《Cladistics : the international journal of the Willi Hennig Society》2011,27(2):171-180
We present SequenceMatrix, software that is designed to facilitate the assembly and analysis of multi‐gene datasets. Genes are concatenated by dragging and dropping FASTA, NEXUS, or TNT files with aligned sequences into the program window. A multi‐gene dataset is concatenated and displayed in a spreadsheet; each sequence is represented by a cell that provides information on sequence length, number of indels, the number of ambiguous bases (“Ns”), and the availability of codon information. Alternatively, GenBank numbers for the sequences can be displayed and exported. Matrices with hundreds of genes and taxa can be concatenated within minutes and exported in TNT, NEXUS, or PHYLIP formats, preserving both character set and codon information for TNT and NEXUS files. SequenceMatrix also creates taxon sets listing taxa with a minimum number of characters or gene fragments, which helps assess preliminary datasets. Entire taxa, whole gene fragments, or individual sequences for a particular gene and species can be excluded from export. Data matrices can be re‐split into their component genes and the gene fragments can be exported as individual gene files. SequenceMatrix also includes two tools that help to identify sequences that may have been compromised through laboratory contamination or data management error. One tool lists identical or near‐identical sequences within genes, while the other compares the pairwise distance pattern of one gene against the pattern for all remaining genes combined. SequenceMatrix is Java‐based and compatible with the Microsoft Windows, Apple MacOS X and Linux operating systems. The software is freely available from http://code.google.com/p/sequencematrix/ . © The Willi Hennig Society 2010. 相似文献
999.
1000.
Mueller R Rachwal S Tedder ME Li YX Zhong S Hampson A Ulas J Varney M Nielsson L Rogers G 《Bioorganic & medicinal chemistry letters》2011,21(13):3927-3930
AMPA receptors (AMPARs) are an important therapeutic target in the CNS. A series of substituted benzoxazinone derivatives with good to very good in vitro activity as positive allosteric AMPAR modulators was synthesized and evaluated. The appropriate substituent choice on the benzoxazinone fragment improved the affinity towards the AMPA receptor significantly in comparison to our lead molecule CX614. 相似文献