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21.
The molecular mechanisms of toxicity associated with cytoplasmic accumulation of TAR DNA binding protein-43(TDP-43),a pathological feature of many neurodegenera... 相似文献
22.
23.
The Drosophila peptidoglycan recognition protein PGRP-LF blocks PGRP-LC and IMD/JNK pathway activation 总被引:1,自引:0,他引:1
Eukaryotic peptidoglycan recognition proteins (PGRPs) are related to bacterial amidases. In Drosophila, PGRPs bind peptidoglycan and function as central sensors and regulators of the innate immune response. PGRP-LC/PGRP-LE constitute the receptor complex in the immune deficiency (IMD) pathway, which is an innate immune cascade triggered upon Gram-negative bacterial infection. Here, we present the functional analysis of the nonamidase, membrane-associated PGRP-LF. We show that PGRP-LF acts as a specific negative regulator of the IMD pathway. Reduction of PGRP-LF levels, in the absence of infection, is sufficient to trigger IMD pathway activation. Furthermore, normal development is impaired in the absence of functional PGRP-LF, a phenotype mediated by the JNK pathway. Thus, PGRP-LF prevents constitutive activation of both the JNK and the IMD pathways. We propose a model in which PGRP-LF keeps the Drosophila IMD pathway silent by sequestering circulating peptidoglycan. 相似文献
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Julien M Verrier B Cerutti M Chappe V Gola M Devauchelle G Becq F 《The Journal of membrane biology》1999,168(3):229-239
Increasing evidence is now accumulating for the involvement of the cystic fibrosis transmembrane conductance regulator (CFTR)
in the control of the outwardly rectifying chloride channel (ORCC). We have examined the sensitivity of ORCC to the sulfonylurea
drug glibenclamide in Hi-5 (Trichoplusia ni) insect cells infected with recombinant baculovirus expressing either wild-type CFTR, ΔF508-CFTR or E. coliβ galactosidase cDNA and in control cells either infected with virus alone or uninfected. Iodide efflux and single channel
patch-clamp experiments confirmed that forskolin and 1-methyl-3-isobutyl xanthine (IBMX) or 7-methyl-1,3 dipropyl xanthine
(DPMX) activate CFTR channels (unitary conductance: 9.1 ± 1.6 pS) only in cells expressing CFTR. In contrast, we identified
4-acetamido-4′-isothiocyanatostilbene-2,2′-disulfonic acid (SITS)-sensitive ORCC in excised membrane patches in any of the
cells studied, with similar conductance (22 ± 2.5 pS at −80 mV; 55 ± 4.1 pS at +80 mV) and properties. In the presence of
500 μm SITS, channel open probability (P
o
) of ORCC was reversibly reduced to 0.05 ± 0.01 in CFTR-cells, to 0.07 ± 0.02 in non-CFTR expressing cells and to 0.05 ± 0.02
in ΔF508-cells. In Hi-5 cells that did not express CFTR, glibenclamide failed to inhibit ORCC activity even at high concentrations
(100 μm), whereas 500 μm SITS reversibly inhibited ORCC. In contrast in cells expressing CFTR or ΔF508, glibenclamide dose dependently (IC50= 17 μm, Hill coefficient 1.2) and reversibly inhibited ORCC. Cytoplasmic application of 100 μm glibenclamide reversibly reduced P
o
from 0.88 ± 0.03 to 0.09 ± 0.02 (wash: P
o
= 0.85 ± 0.1) in CFTR cells and from 0.89 ± 0.05 to 0.08 ± 0.05 (wash: P
o
= 0.87 ± 0.1) in ΔF508 cells. In non-CFTR expressing cells, glibenclamide (100 μm) was without effect on P
o
(control: P
o
= 0.89 ± 0.09, glib.: P
o
= 0.86 ± 0.02; wash: P
o
= 0.87 ± 0.05). These data strongly suggest that the expression of CFTR confers glibenclamide sensitivity to the ORCC in Hi-5
cells.
Received: 23 October 1998/Revised: 29 December 1998 相似文献
26.
Garcia A Cayla X Guergnon J Dessauge F Hospital V Rebollo MP Fleischer A Rebollo A 《Biochimie》2003,85(8):721-726
The reversible phosphorylation of proteins controlled by protein kinases and protein phosphatases is a major mechanism that regulates a wide variety of cellular processes. In contrast to C. elegans, recent studies in mammalian cells have highlighted a major role of serine/threonine protein phosphorylation in apoptosis. To illustrate the importance of dephosphorylation processes in apoptosis, this review will focus on recent studies suggesting that the interaction of the serine/threonine protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) with certain regulators of the Bcl-2 family is critically involved in the control of apoptosis. 相似文献
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Abstract Using plasma glycoprotein glycans, a correlation was established between their inhibitory capacity of sheep mannose-resistant haemagglutination (MRHA) properties of bovine enterotoxigenic Escherichia coli (ETEC) and their monosaccharide content. Sialic acid seems to be the major component of the inhibitors of adherence of calf ETEC. 相似文献
29.
Julien Cappelle Delong Zhao Marius Gilbert Martha I. Nelson Scott H. Newman John Y. Takekawa Nicolas Gaidet Diann J. Prosser Ying Liu Peng Li Yuelong Shu Xiangming Xiao 《EcoHealth》2014,11(1):109-119
For decades, southern China has been considered to be an important source for emerging influenza viruses since key hosts live together in high densities in areas with intensive agriculture. However, the underlying conditions of emergence and spread of avian influenza viruses (AIV) have not been studied in detail, particularly the complex spatiotemporal interplay of viral transmission between wild and domestic ducks, two major actors of AIV epidemiology. In this synthesis, we examine the risks of avian influenza spread in Poyang Lake, an area of intensive free-ranging duck production and large numbers of wild waterfowl. Our synthesis shows that farming of free-grazing domestic ducks is intensive in this area and synchronized with wild duck migration. The presence of juvenile domestic ducks in harvested paddy fields prior to the arrival and departure of migrant ducks in the same fields may amplify the risk of AIV circulation and facilitate the transmission between wild and domestic populations. We provide evidence associating wild ducks migration with the spread of H5N1 in the spring of 2008 from southern China to South Korea, Russia, and Japan, supported by documented wild duck movements and phylogenetic analyses of highly pathogenic avian influenza H5N1 sequences. We suggest that prevention measures based on a modification of agricultural practices may be implemented in these areas to reduce the intensity of AIV transmission between wild and domestic ducks. This would require involving all local stakeholders to discuss feasible and acceptable solutions. 相似文献
30.
Julien Foucaud Céline Moreno Marta Pascual Enrico L. Rezende Luis E. Castañeda Patricia Gibert Frederic Mery 《Ecology and evolution》2016,6(6):1725-1736
The success of invasive species is tightly linked to their fitness in a putatively novel environment. While quantitative components of fitness have been studied extensively in the context of invasive species, fewer studies have looked at qualitative components of fitness, such as behavioral plasticity, and their interaction with quantitative components, despite intuitive benefits over the course of an invasion. In particular, learning is a form of behavioral plasticity that makes it possible to finely tune behavior according to environmental conditions. Learning can be crucial for survival and reproduction of introduced organisms in novel areas, for example, for detecting new predators, or finding mates or oviposition sites. Here we explored how oviposition performance evolved in relation to both fecundity and learning during an invasion, using native and introduced Drosophila subobscura populations performing an ecologically relevant task. Our results indicated that, under comparable conditions, invasive populations performed better during our oviposition task than did native populations. This was because invasive populations had higher fecundity, together with similar cognitive performance when compared to native populations, and that there was no interaction between learning and fecundity. Unexpectedly, our study did not reveal an allocation trade‐off (i.e., a negative relationship) between learning and fecundity. On the contrary, the pattern we observed was more consistent with an acquisition trade‐off, meaning that fecundity could be limited by availability of resources, unlike cognitive ability. This pattern might be the consequence of escaping natural enemies and/or competitors during the introduction. The apparent lack of evolution of learning may indicate that the introduced population did not face novel cognitive challenges in the new environment (i.e., cognitive “pre‐adaptation”). Alternatively, the evolution of learning may have been transient and therefore not detected. 相似文献