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991.
Veeramah KR O'Brien JE Meisler MH Cheng X Dib-Hajj SD Waxman SG Talwar D Girirajan S Eichler EE Restifo LL Erickson RP Hammer MF 《American journal of human genetics》2012,90(3):502-510
Individuals with severe, sporadic disorders of infantile onset represent an important class of disease for which discovery of the underlying genetic architecture is not amenable to traditional genetic analysis. Full-genome sequencing of affected individuals and their parents provides a powerful alternative strategy for gene discovery. We performed whole-genome sequencing (WGS) on a family quartet containing an affected proband and her unaffected parents and sibling. The 15-year-old female proband had a severe epileptic encephalopathy consisting of early-onset seizures, features of autism, intellectual disability, ataxia, and sudden unexplained death in epilepsy. We discovered a de novo heterozygous missense mutation (c.5302A>G [p.Asn1768Asp]) in the voltage-gated sodium-channel gene SCN8A in the proband. This mutation alters an evolutionarily conserved residue in Nav1.6, one of the most abundant sodium channels in the brain. Analysis of the biophysical properties of the mutant channel demonstrated a dramatic increase in persistent sodium current, incomplete channel inactivation, and a depolarizing shift in the voltage dependence of steady-state fast inactivation. Current-clamp analysis in hippocampal neurons transfected with p.Asn1768Asp channels revealed increased spontaneous firing, paroxysmal-depolarizing-shift-like complexes, and an increased firing frequency, consistent with a dominant gain-of-function phenotype in the heterozygous proband. This work identifies SCN8A as the fifth sodium-channel gene to be mutated in epilepsy and demonstrates the value of WGS for the identification of pathogenic mutations causing severe, sporadic neurological disorders. 相似文献
992.
Cells use molecular motors, such as myosins, to move, position and segregate their organelles. Class V myosins possess biochemical and structural properties that should make them ideal actin-based cargo transporters. Indeed, studies show that class V myosins function as cargo transporters in yeast, moving a range of organelles, such as the vacuole, peroxisomes and secretory vesicles. There is also increasing evidence in vertebrate cells that class V myosins not only tether organelles to actin but also can serve as short-range, point-to-point organelle transporters, usually following long-range, microtubule-dependent organelle transport. 相似文献
993.
994.
Jemanesh K. Haile Miloudi M. Nachit Karl Hammer Ayele Badebo Marion S. R?der 《Molecular breeding : new strategies in plant improvement》2012,30(3):1479-1493
Stem rust caused by Puccinia graminis f. sp. tritici was historically one of the most destructive diseases of wheat worldwide. The evolution and rapid migration of race TTKSK (Ug99) and derivatives, first detected in Uganda in 1999, are of international concern due to the virulence of these races to widely used stem rust resistance genes. In attempts to identify quantitative trait loci (QTL) linked with resistance to stem rust race Ug99, 95 recombinant inbred lines that were developed from a cross between two durum wheat varieties, Kristal and Sebatel, were evaluated for reaction to stem rust. Seven field trials at two locations were carried out in main and off seasons. In addition to the natural infection, the nursery was also artificially inoculated with urediniospores of stem rust race Ug99 and a mixture of locally collected stem rust urediniospores. A genetic map was constructed based on 207 simple sequence repeat (SSR) and two sequence tagged site loci. Using composite interval mapping, nine QTL for resistance to stem rust were identified on chromosomes 1AL, 2AS, 3BS, 4BL, 5BL, 6AL 7A, 7AL and 7BL. These results suggest that durum wheat resistance to stem rust is oligogenic and that there is potential to identify previously uncharacterized resistance genes with minor effects. The SSR markers that are closely linked to the QTL can be used for marker-assisted selection for stem rust resistance in durum wheat. 相似文献
995.
Krille L Zeeb H Jahnen A Mildenberger P Seidenbusch M Schneider K Weisser G Hammer G Scholz P Blettner M 《Radiation and environmental biophysics》2012,51(2):103-111
Radiation protection is a topic of great public concern and of many scientific investigations, because ionizing radiation
is an established risk factor for leukaemia and many solid tumours. Exposure of the public to ionizing radiation includes
exposure to background radiation, as well as medical and occupational exposures. A large fraction of the exposure from diagnostic
procedures comes from medical imaging. Computed tomography (CT) is the major single contributor of diagnostic radiation exposure.
An increase in the use of CTs has been reported over the last decades in many countries. Children have smaller bodies and
lower shielding capacities, factors that affect the individual organ doses due to medical imaging. Several risk models have
been applied to estimate the cancer burden caused by ionizing radiation from CT. All models predict higher risks for cancer
among children exposed to CT as compared to adults. However, the cancer risk associated with CT has not been assessed directly
in epidemiological studies. Here, plans are described to conduct an historical cohort study to investigate the cancer incidence
in paediatric patients exposed to CT before the age of 15 in Germany. Patients will be recruited from radiology departments
of several hospitals. Their individual exposure will be recorded, and time-dependent cumulative organ doses will be calculated.
Follow-up for cancer incidence via the German Childhood Cancer Registry will allow computation of standardized incidence ratios
using population-based incidence rates for childhood cancer. Dose–response modelling and analyses for subgroups of children
based on the indication for and the result of the CT will be performed. 相似文献
996.
Addressing Research Bottlenecks to Crop Productivity 总被引:2,自引:0,他引:2
Matthew Reynolds Owen K. Atkin Malcolm Bennett Mark Cooper Ian C. Dodd M. John Foulkes Claus Frohberg Graeme Hammer Ian R. Henderson Bingru Huang Viktor Korzun Susan R. McCouch Carlos D. Messina Barry J. Pogson Gustavo A. Slafer Nicolas L. Taylor Peter E. Wittich 《Trends in plant science》2021,26(6):607-630
997.
Hammer G Cooper M Tardieu F Welch S Walsh B van Eeuwijk F Chapman S Podlich D 《Trends in plant science》2006,11(12):587-593
Progress in breeding higher-yielding crop plants would be greatly accelerated if the phenotypic consequences of making changes to the genetic makeup of an organism could be reliably predicted. Developing a predictive capacity that scales from genotype to phenotype is impeded by biological complexities associated with genetic controls, environmental effects and interactions among plant growth and development processes. Plant modelling can help navigate a path through this complexity. Here we profile modelling approaches for complex traits at gene network, organ and whole plant levels. Each provides a means to link phenotypic consequence to changes in genomic regions via stable associations with model coefficients. A unifying feature of the models is the relatively coarse level of granularity they use to capture system dynamics. Much of the fine detail is not directly required. Robust coarse-grained models might be the tool needed to integrate phenotypic and molecular approaches to plant breeding. 相似文献
998.
The plus-end of the microtubule has a central role in the interactions that occur between the microtubule and actin cytoskeletons. The recent identification of a family of proteins that congregate at the plus-end is enabling an increased mechanistic understanding of how this cross talk is accomplished. These proteins, termed plus-end tracking proteins because they appear to associate with the plus-end as it grows, have already been shown to regulate microtubule dynamics and to facilitate the formation of connections between the plus-end and the actin-rich cortex. Several motor proteins, including an actin-based motor, microtubule-based motors that move towards either end of the microtubule and microtubule motors that depolymerize microtubule ends, can now be added to the list of plus-end tracking proteins. Here, we discuss how the presence of these motors at the plus-end seems to drive several fundamental cellular processes involving force generation at the interface between microtubule ends and the cortex, vesicle translocation following search and capture, microtubule disassembly and the delivery of signals to the cortex that govern actin assembly and cell polarity. 相似文献
999.
Summary. We have studied the enzymatic derivatization of amino acids by use of the polyphenol oxidase laccase. Derivatization of L-tryptophan
was achieved by enzymatic crosslinking with the laccase substrate 2,5-dihydroxy-N-(2-hydroxyethyl)-benzamide. The main product
(yield up to 70%) was identified as the quinoid compound 2-[2-(2-hydroxy-ethylcarbamoyl)-3,6-dioxo-cyclohexa-1,4-dienylamino]-3-(1H-indol-3-yl)-
propionic acid and demonstrates that laccase-catalyzed C–N-coupling occurred on the amino group of the aliphatic side chain.
These enzyme based reactions provide a simple and fast method for the derivatization of unprotected amino acids. 相似文献
1000.
Beffert U Nematollah Farsian F Masiulis I Hammer RE Yoon SO Giehl KM Herz J 《Current biology : CB》2006,16(24):2446-2452
A central pathogenic feature of neurodegenerative diseases and neurotrauma is the death of neurons. A mechanistic understanding of the factors and conditions that induce the dysfunction and death of neurons is essential for devising effective treatment strategies against neuronal loss after trauma or during aging. Because Apolipoprotein E (ApoE) is a major risk factor for several neurodegenerative diseases, including Alzheimer's disease , a direct or indirect role of ApoE receptors in the disease process is likely. Here we have used gene targeting in mice to investigate possible roles of ApoE receptors in the regulation of neuronal survival. We demonstrate that a differentially spliced isoform of an ApoE receptor, ApoE receptor 2 (Apoer2), is essential for protection against neuronal cell loss during normal aging. Furthermore, the same splice form selectively promotes neuronal cell death after injury through mechanisms that may involve serine/threonine kinases of the Jun N-terminal kinase (JNK) family. These findings raise the possibility that ApoE and its receptors cooperatively regulate common mechanisms that are essential to neuronal survival in the adult brain. 相似文献