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961.
Jessica?L.?Dunne Adam?P.?Goobic Scott?T.?Acton Klaus?LeyEmail author 《Biological procedures online》2004,6(1):173-179
Leukocyte endothelial cell interaction is a fundamentally important process in many disease states. Current methods to analyze
such interactions include the parallel-plate flow chamber and intravital microscopy. Here, we present an improvement of the
traditional intravital microscopy that allows leukocyte-endothelial cell interaction to be studied from the time the leukocyte
makes its initial contact with the endothelium until it adheres to or detaches from the endothelium. The leukocyte is tracked
throughout the venular tree with the aid of a motorized stage and the rolling and adhesive behavior is measured off-line.
Because this method can involve human error, methods to automate the tracking procedure have been developed. This novel tracking
method allows for a more detailed examination of leukocyte-endothelial cell interactions.
Published: August 27, 2004. 相似文献
962.
Syka JE Marto JA Bai DL Horning S Senko MW Schwartz JC Ueberheide B Garcia B Busby S Muratore T Shabanowitz J Hunt DF 《Journal of proteome research》2004,3(3):621-626
We describe the design and performance of a prototype high performance hybrid mass spectrometer. This instrument consists of a linear quadrupole ion trap (QLT) coupled to a Fourier transform ion cyclotron resonance mass analyzer (FTMS). This configuration provides rapid and automated MS and MS/MS analyses, similar to the "data dependent scanning" found on standard 3-D Paul traps, but with substantially improved internal scan dynamic range, mass measurement accuracy, mass resolution, and detection limits. Sequence analysis of peptides at the zeptomole level is described. The recently released, commercial version of this instrument operates in the LC/MS mode (1 s/scan) with a mass resolution of 100 000 and is equipped with automatic gain control to provide mass measurement accuracy of 1-2 ppm without internal standard. Methodology is described that uses this instrument to compare the post-translational modifications present on histone H3 isolated from asynchronously growing cells and cells arrested in mitosis. 相似文献
963.
Wang QT Piotrowska K Ciemerych MA Milenkovic L Scott MP Davis RW Zernicka-Goetz M 《Developmental cell》2004,6(1):133-144
The preimplantation development of the mammalian embryo encompasses a series of critical events: the transition from oocyte to embryo, the first cell divisions, the establishment of cellular contacts, the first lineage differentiation-all the first subtle steps toward a future body plan. Here, we use microarrays to explore gene activity during preimplantation development. We reveal robust and dynamic patterns of stage-specific gene activity that fall into two major phases, one up to the 2-cell stage (oocyte-to-embryo transition) and one after the 4-cell stage (cellular differentiation). The mouse oocyte and early embryo express components of multiple signaling pathways including those downstream of Wnt, BMP, and Notch, indicating that conserved regulators of cell fate and pattern formation are likely to function at the earliest embryonic stages. Overall, these data provide a detailed temporal profile of gene expression that reveals the richness of signaling processes in early mammalian development. 相似文献
964.
To further our knowledge of intracellular copper transport, we used a proteomics strategy to search for hepatic proteins with copper-binding ability. Hep G2 cytosolic and microsomal fractions were applied to a copper(II)-loaded immobilized metal-affinity chromatography (IMAC) column. Protein identification was performed with 2-D gel electrophoresis and mass spectrometry. We identified 48 cytosolic proteins and 19 microsomal proteins displaying copper-binding ability. These proteins are diverse in function. Fifty-two of the 67 proteins contain putative metal-binding domains. We have identified many components of the Hep G2 copper metalloproteome including a large number of proteins not previously known to bind copper. 相似文献
965.
966.
967.
968.
BACKGROUND: The localization of glutamate receptors is essential for the formation and plasticity of excitatory synapses. These receptors cluster opposite neurotransmitter release sites of glutamatergic neurons, but these release sites have heterogeneous structural and functional properties. At the Drosophila neuromuscular junction, receptors expressed in a single postsynaptic cell are confronted with an array of hundreds of apposed active zones. Hence, this is an ideal preparation for the investigation of whether receptor clustering is sensitive to the morphological and physiological properties of the apposed active zones. RESULTS: To investigate the relationship between the localization of glutamate receptors and the properties of the apposed active zones, we investigated receptor localization in mutants in which receptors are limited. We find that receptors are not uniformly distributed opposite the full array of active zones but that some active zones have a disproportionately large share of receptors as assayed by receptor levels and response to transmitter. The active zones at which receptors preferentially cluster are larger and have a higher neurotransmitter release probability than the average active zone. We find a similar relationship between glutamate receptor clusters and active-zone size at wild-type synapses. CONCLUSIONS: When confronted with an array of active zones, glutamate receptors preferentially cluster opposite the largest and most physiologically active sites. These results suggest an activity-dependent matching of pre- and postsynaptic function at the level of a single active zone. 相似文献
969.
Based on simulation modelling, Kaitala and Ranta (2001 Proc. R. Soc. Lond. B 268, 1769-1774) have argued that detecting the statistical relationships between environmental variability and population fluctuations will be difficult. However, their study was limited in that only one pattern of density dependence and one detection method were used. Here, we show that their conclusion is in part a consequence of their choice of population model and in part a consequence of using relatively weak or inappropriate statistical methods. Other patterns of density dependence respond differently to environmental fluctuations, and the impact of the disturbance on these is clearly visible using their methods. For some patterns of population dynamics, environmental impacts are more readily detectable by correlating running-average environmental conditions with the population time-series or by correlating the first differences of the population time-series with environmental noise. When more appropriate statistical methods are used, environmental forcing is detectable in the majority of cases used by Kaitala and Ranta. The interplay between environmental stochasticity and density-dependent population growth means that there is no single best method to detect the influence of environmental forcing, even when population dynamics are approximately linear. But environmental forcing will often be detectable, contrary to Kaitala and Ranta's assertions. 相似文献
970.
Animal origins of SARS coronavirus: possible links with the international trade in small carnivores 总被引:5,自引:0,他引:5
Bell D Roberton S Hunter PR 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2004,359(1447):1107-1114
The search for animal host origins of severe acute respiratory syndrome (SARS) coronavirus has so far remained focused on wildlife markets, restaurants and farms within China. A significant proportion of this wildlife enters China through an expanding regional network of illegal, international wildlife trade. We present the case for extending the search for ancestral coronaviruses and their hosts across international borders into countries such as Vietnam and Lao People's Democratic Republic, where the same guilds of species are found on sale in similar wildlife markets or food outlets. The three species that have so far been implicated, a viverrid, a mustelid and a canid, are part of a large suite of small carnivores distributed across this region currently overexploited by this international wildlife trade. A major lesson from SARS is that the underlying roots of newly emergent zoonotic diseases may lie in the parallel biodiversity crisis of massive species loss as a result of overexploitation of wild animal populations and the destruction of their natural habitats by increasing human populations. To address these dual threats to the long-term future of biodiversity, including man, requires a less anthropocentric and more interdisciplinary approach to problems that require the combined research expertise of ecologists, conservation biologists, veterinarians, epidemiologists, virologists, as well as human health professionals. 相似文献