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Giora Hon Bernard R. Goldstein 《Studies in History and Philosophy of Science Part B: Studies in History and Philosophy of Modern Physics》2012,43(4):236-257
The term “analogy” stands for a variety of methodological practices all related in one way or another to the idea of proportionality. We claim that in his first substantial contribution to electromagnetism James Clerk Maxwell developed a methodology of analogy which was completely new at the time or, to borrow John North’s expression, Maxwell’s methodology was a “newly contrived analogue”. In his initial response to Michael Faraday’s experimental researches in electromagnetism, Maxwell did not seek an analogy with some physical system in a domain different from electromagnetism as advocated by William Thomson; rather, he constructed an entirely artificial one to suit his needs. Following North, we claim that the modification which Maxwell introduced to the methodology of analogy has not been properly appreciated. In view of our examination of the evidence, we argue that Maxwell gave a new meaning to analogy; in fact, it comes close to modeling in current usage. 相似文献
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B Goldstein 《Nature》1992,357(6375):255-257
Two types of developmental events can cause an embryonic cell to adopt a fate different from that of its neighbours: during a cell division particular contents may be segregated to only one daughter cell and cells may experience different external cues, commonly in the form of inductive cell interactions. Work on development in the nematode Caenorhabditis elegans suggests that most cell fates are specified without a need for cell interactions. In particular, the gut cell lineage of C. elegans has been used as a primary example of specification by differential segregation of determinants. Here I re-examine the role of induction in gut specification by isolating early blastomeres. In C. elegans, the gut derives from all the progeny of a single blastomere (E) of the eight-cell stage. When a gut precursor cell (EMS) is isolated during the first half of the four-cell stage, gut does not differentiate. Gut differentiation is rescued by recombining EMS with its posterior neighbour (P2), but not by recombining EMS with one or both of the other two cells of the four-cell stage. These results demonstrate that P2 induces EMS to form gut in C. elegans. 相似文献
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D J Goldstein M E Finbow T Andresson P McLean K Smith V Bubb R Schlegel 《Nature》1991,352(6333):347-349
The major transforming protein of bovine papillomavirus type 1, E5, is mainly associated with endomembranes, specifically binding to a cellular protein of relative molecular mass 16,000 (16K). At the same time as transformation, E5 causes the phosphorylation of tyrosine residues in epidermal and platelet-derived growth factor receptors. We show here that the 16K protein associated with E5 is the 16K component of vacuolar ATPases. This protein is known to be an integral membrane protein in endosomes, bovine chromaffin granules, synaptic vesicles, fungal and plant vacuoles and clathrin-coated vesicles, as well as a component of gap-junction-like membrane complexes. Because proton pumps are critical for the function of cellular compartments that process growth-factor receptors, the interaction of E5 with the 16K protein could explain the pleiomorphic features of cells transformed by E5. 相似文献
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Probing sporadic and familial Alzheimer's disease using induced pluripotent stem cells 总被引:1,自引:0,他引:1
Israel MA Yuan SH Bardy C Reyna SM Mu Y Herrera C Hefferan MP Van Gorp S Nazor KL Boscolo FS Carson CT Laurent LC Marsala M Gage FH Remes AM Koo EH Goldstein LS 《Nature》2012,482(7384):216-220
Our understanding of Alzheimer's disease pathogenesis is currently limited by difficulties in obtaining live neurons from patients and the inability to model the sporadic form of the disease. It may be possible to overcome these challenges by reprogramming primary cells from patients into induced pluripotent stem cells (iPSCs). Here we reprogrammed primary fibroblasts from two patients with familial Alzheimer's disease, both caused by a duplication of the amyloid-β precursor protein gene (APP; termed APP(Dp)), two with sporadic Alzheimer's disease (termed sAD1, sAD2) and two non-demented control individuals into iPSC lines. Neurons from differentiated cultures were purified with fluorescence-activated cell sorting and characterized. Purified cultures contained more than 90% neurons, clustered with fetal brain messenger RNA samples by microarray criteria, and could form functional synaptic contacts. Virtually all cells exhibited normal electrophysiological activity. Relative to controls, iPSC-derived, purified neurons from the two APP(Dp) patients and patient sAD2 exhibited significantly higher levels of the pathological markers amyloid-β(1-40), phospho-tau(Thr?231) and active glycogen synthase kinase-3β (aGSK-3β). Neurons from APP(Dp) and sAD2 patients also accumulated large RAB5-positive early endosomes compared to controls. Treatment of purified neurons with β-secretase inhibitors, but not γ-secretase inhibitors, caused significant reductions in phospho-Tau(Thr?231) and aGSK-3β levels. These results suggest a direct relationship between APP proteolytic processing, but not amyloid-β, in GSK-3β activation and tau phosphorylation in human neurons. Additionally, we observed that neurons with the genome of one sAD patient exhibited the phenotypes seen in familial Alzheimer's disease samples. More generally, we demonstrate that iPSC technology can be used to observe phenotypes relevant to Alzheimer's disease, even though it can take decades for overt disease to manifest in patients. 相似文献
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Functional corticotropin releasing factor receptors in the primate peripheral sympathetic nervous system 总被引:8,自引:0,他引:8
R Udelsman J P Harwood M A Millan G P Chrousos D S Goldstein R Zimlichman K J Catt G Aguilera 《Nature》1986,319(6049):147-150
Corticotropin releasing factor (CRF) is a key hormone in the integrated response to stress, acting both as the major regulator of pituitary adrenocorticotropic hormone (ACTH) release and as a neuropeptide in the brain. The actions of CRF are mediated by specific plasma membrane receptors in the anterior pituitary gland and in discrete brain areas including the cerebral cortex and several regions related to the limbic system. In addition to the pituitary and central actions of CRF, systemic administration of the peptide in the rat, dog, monkey and man causes hypotension and tachycardia because of a decrease in peripheral vascular resistance. These observations, in conjunction with the finding of immunoreactive and bioactive CRF in peripheral tissues, suggest that the peptide is locally released in tissues to act as a neurotransmitter or paracrine hormone. As CRF is present in the adrenal medulla and the peptide is known to modulate the central activity of the autonomic nervous system, we investigated the possibility that CRF is involved in the regulation of the peripheral autonomic nervous system. Such an action of CRF is supported by our demonstration of specific CRF receptors in the monkey adrenal medulla and sympathetic ganglia. In the adrenal medulla, these receptors are coupled to adenylate cyclase and can stimulate the secretion of catecholamines and Met-enkephalin. 相似文献
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