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991.
Sai Kishore N Visarada KB Aravinda Lakshmi Y Pashupatinath E Rao SV Seetharama N 《Plant cell reports》2006,25(3):174-182
Twenty-four diverse genotypes of sorghum were evaluated for response to callus induction and plant regeneration with two media
viz., MS and NBKNB using shoot tips as the start material to identify a model genotype. None of the genotypes tested showed
promising results. Therefore, alternative methods of in vitro pathways using shoot meristem isolated from shoot tips were
explored. Shoot apical meristems were isolated and were induced to multiple shoots or multiple shoot buds pathway by manipulation
of thidiazuron (TDZ), 6-benzyl adenine (BAP) and 2, 4-dichlorophenoxy acetic acid (2, 4-D). Choice of the pathway whether
large-scale multiplication of shoots or production of target tissues for transformation can be exercised based on the needs
and applications. A simple procedure, for large scale handling of shoot tips is described in detail. Electron microscopic
studies revealed that meristems isolated from 7-day-old seedlings are superior because of possessing greater number of transformation
competent cells. 相似文献
992.
Pignatari GC Rozenfeld R Ferro ES Oliveira L Paiva AC Devi LA 《Biological chemistry》2006,387(3):269-276
Several studies have proposed that angiotensin II (Ang II) binds to its receptor AT1 through interactions with residues in helices V and VI, suggesting that the distance between these helices is crucial for ligand binding. Based on a 3D model of AT1 in which the C-terminus of Ang II is docked, we identified the hydrophobic residues of TM V and VI pointing towards the external face of the helices, which may play a role in the structure of the binding pocket and in the structural integrity of the receptor. We performed a systematic mutagenesis study of these residues and examined the binding, localization, maturation, and dimerization of the mutated receptors. We found that mutations of hydrophobic residues to alanine in helix V do not alter binding, whereas mutations to glutamate lead to loss of binding without a loss in cell surface expression, suggesting that the external face of helix V may not directly participate in binding, but may rather contribute to the structure of the binding pocket. In contrast, mutations of hydrophobic residues to glutamate in helix VI lead to a loss in cell surface expression, suggesting that the external surface of helix VI plays a structural role and ensures correct folding of the receptor. 相似文献
993.
Electronic Nose based ENT bacteria identification in hospital environment is a classical and challenging problem of classification.
In this paper an electronic nose (e-nose), comprising a hybrid array of 12 tin oxide sensors (SnO2) and 6 conducting polymer sensors has been used to identify three species of bacteria, Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Pseudomonas aeruginosa (P. aeruginosa) responsible for ear nose and throat (ENT) infections when collected as swab sample from infected patients and kept in ISO
agar solution in the hospital environment. In the next stage a sub-classification technique has been developed for the classification
of two different species of S. aureus, namely Methicillin-Resistant S. aureus (MRSA) and Methicillin Susceptible S. aureus
(MSSA). An innovative Intelligent Bayes Classifier (IBC) based on "Baye's theorem" and "maximum probability rule" was developed
and investigated for these three main groups of ENT bacteria. Along with the IBC three other supervised classifiers (namely,
Multilayer Perceptron (MLP), Probabilistic neural network (PNN), and Radial Basis Function Network (RBFN)) were used to classify
the three main bacteria classes. A comparative evaluation of the classifiers was conducted for this application. IBC outperformed
MLP, PNN and RBFN. The best results suggest that we are able to identify and classify three bacteria main classes with up
to 100% accuracy rate using IBC. We have also achieved 100% classification accuracy for the classification of MRSA and MSSA
samples with IBC. We can conclude that this study proves that IBC based e-nose can provide very strong and rapid solution
for the identification of ENT infections in hospital environment. 相似文献
994.
An integrated strategy for analyzing the unique developmental programs of different myoblast subtypes 下载免费PDF全文
Estrada B Choe SE Gisselbrecht SS Michaud S Raj L Busser BW Halfon MS Church GM Michelson AM 《PLoS genetics》2006,2(2):e16
An important but largely unmet challenge in understanding the mechanisms that govern the formation of specific organs is to decipher the complex and dynamic genetic programs exhibited by the diversity of cell types within the tissue of interest. Here, we use an integrated genetic, genomic, and computational strategy to comprehensively determine the molecular identities of distinct myoblast subpopulations within the Drosophila embryonic mesoderm at the time that cell fates are initially specified. A compendium of gene expression profiles was generated for primary mesodermal cells purified by flow cytometry from appropriately staged wild-type embryos and from 12 genotypes in which myogenesis was selectively and predictably perturbed. A statistical meta-analysis of these pooled datasets—based on expected trends in gene expression and on the relative contribution of each genotype to the detection of known muscle genes—provisionally assigned hundreds of differentially expressed genes to particular myoblast subtypes. Whole embryo in situ hybridizations were then used to validate the majority of these predictions, thereby enabling true-positive detection rates to be estimated for the microarray data. This combined analysis reveals that myoblasts exhibit much greater gene expression heterogeneity and overall complexity than was previously appreciated. Moreover, it implicates the involvement of large numbers of uncharacterized, differentially expressed genes in myogenic specification and subsequent morphogenesis. These findings also underscore a requirement for considerable regulatory specificity for generating diverse myoblast identities. Finally, to illustrate how the developmental functions of newly identified myoblast genes can be efficiently surveyed, a rapid RNA interference assay that can be scored in living embryos was developed and applied to selected genes. This integrated strategy for examining embryonic gene expression and function provides a substantially expanded framework for further studies of this model developmental system. 相似文献
995.
996.
Luu RA Gurnani K Dudani R Kammara R van Faassen H Sirard JC Krishnan L Sad S 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(3):1516-1525
Ag presentation to CD8(+) T cells often commences immediately after infection, which facilitates their rapid expansion and control of infection. Subsequently, the primed cells undergo rapid contraction. We report that this paradigm is not followed during infection with virulent Salmonella enterica, serovar Typhimurium (ST), an intracellular bacterium that replicates within phagosomes of infected cells. Although susceptible mice die rapidly (approximately 7 days), resistant mice (129 x 1SvJ) harbor a chronic infection lasting approximately 60-90 days. Using rOVA-expressing ST (ST-OVA), we show that T cell priming is considerably delayed in the resistant mice. CD8(+) T cells that are induced during ST-OVA infection undergo delayed expansion, which peaks around day 21, and is followed by protracted contraction. Initially, ST-OVA induces a small population of cycling central phenotype (CD62L(high)IL-7Ralpha(high)CD44(high)) CD8(+) T cells. However, by day 14-21, majority of the primed CD8(+) T cells display an effector phenotype (CD62L(low)IL-7Ralpha(low)CD44(high)). Subsequently, a progressive increase in the numbers of effector memory phenotype cells (CD62L(low)IL-7Ralpha(high)CD44(high)) occurs. This differentiation program remained unchanged after accelerated removal of the pathogen with antibiotics, as majority of the primed cells displayed an effector memory phenotype even at 6 mo postinfection. Despite the chronic infection, CD8(+) T cells induced by ST-OVA were functional as they exhibited killing ability and cytokine production. Importantly, even memory CD8(+) T cells failed to undergo rapid expansion in response to ST-OVA infection, suggesting a delay in T cell priming during infection with virulent ST-OVA. Thus, phagosomal lifestyle may allow escape from host CD8(+) T cell recognition, conferring a survival advantage to the pathogen. 相似文献
997.
Noura S. Abul‐Husn Ittai Bushlin José A. Morón Sherry L. Jenkins Georgia Dolios Rong Wang Ravi Iyengar Avi Ma'ayan Lakshmi A. Devi 《Proteomics》2009,9(12):3303-3315
The application of proteomic techniques to neuroscientific research provides an opportunity for a greater understanding of nervous system structure and function. As increasing amounts of neuroproteomic data become available, it is necessary to formulate methods to integrate these data in a meaningful way to obtain a more comprehensive picture of neuronal subcompartments. Furthermore, computational methods can be used to make biologically relevant predictions from large proteomic data sets. Here, we applied an integrated proteomics and systems biology approach to characterize the presynaptic (PRE) nerve terminal. For this, we carried out proteomic analyses of presynaptically enriched fractions, and generated a PRE literature‐based protein–protein interaction network. We combined these with other proteomic analyses to generate a core list of 117 PRE proteins, and used graph theory‐inspired algorithms to predict 92 additional components and a PRE complex containing 17 proteins. Some of these predictions were validated experimentally, indicating that the computational analyses can identify novel proteins and complexes in a subcellular compartment. We conclude that the combination of techniques (proteomics, data integration, and computational analyses) used in this study are useful in obtaining a comprehensive understanding of functional components, especially low‐abundance entities and/or interactions in the PRE nerve terminal. 相似文献
998.
Ascorbate peroxidase,a haem protein (EC 1.11.1.11),efficiently scavenges hydrogen peroxide (H2O2) in cytosol and chloroplasts of plants.In this study,a fulllength coding sequence of thylakoid-bound ascorbate peroxidase cDNA (TatAPX) was cloned from a drought tolerant wheat cultivar C306.Homology modeling of the TatAPX protein was performed by using the template crystal structure of chloroplastic ascorbate peroxidase from tobacco plant (PDB: 1IYN).The model structure was further refined by molecular mechanic... 相似文献
999.
1000.
Lahiri S Basu A Sengupta S Banerjee S Dutta T Soren D Chattopadhyay K Ghosh AK 《Archives of biochemistry and biophysics》2012,522(2):90-99
Trehalose and sucrose, two important anti-stress non-reducing natural disaccharides, are catabolized by two enzymes, namely trehalase and invertase respectively. In this study, a 175 kDa enzyme protein active against both substrates was purified from wild type Candida utilis and characterized in detail. Substrate specificity assay and activity staining revealed the enzyme to be specific for both sucrose and trehalose. The ratio between trehalase and invertase activity was found to be constant at 1:3.5 throughout the entire study. Almost 40-fold purification and 30% yield for both activities were achieved at the final step of purification. The presence of common enzyme inhibitors, thermal and pH stress had analogous effects on its trehalase and invertase activity. Km values for two activities were similar while Vmax and Kcat also differed by a factor of 3.5. Competition plot for both substrates revealed the two activities to be occurring at the single active site. N-terminal sequencing and MALDI-TOF data analysis revealed higher similarity of the purified protein to previously known neutral trehalases. While earlier workers mentioned independent purification of neutral trehalase or invertase from different sources, the present study reports the purification of a single protein showing dual activity. 相似文献