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71.
72.
Perception of edges and visual texture in the camouflage of the common cuttlefish, Sepia officinalis
Zylinski S Osorio D Shohet AJ 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1516):439-448
The cuttlefish, Sepia officinalis, provides a fascinating opportunity to investigate the mechanisms of camouflage as it rapidly changes its body patterns in response to the visual environment. We investigated how edge information determines camouflage responses through the use of spatially high-pass filtered 'objects' and of isolated edges. We then investigated how the body pattern responds to objects defined by texture (second-order information) compared with those defined by luminance. We found that (i) edge information alone is sufficient to elicit the body pattern known as Disruptive, which is the camouflage response given when a whole object is present, and furthermore, isolated edges cause the same response; and (ii) cuttlefish can distinguish and respond to objects of the same mean luminance as the background. These observations emphasize the importance of discrete objects (bounded by edges) in the cuttlefish's choice of camouflage, and more generally imply that figure-ground segregation by cuttlefish is similar to that in vertebrates, as might be predicted by their need to produce effective camouflage against vertebrate predators. 相似文献
73.
Fernando G. Osorio Álvaro J. Obaya Carlos López-Otín José M. P. Freije 《Transgenic research》2009,18(1):7-15
Ageing research benefits from the study of accelerated ageing syndromes such as Hutchinson-Gilford progeria syndrome (HGPS),
characterized by the early appearance of symptoms normally associated with advanced age. Most HGPS cases are caused by a mutation
in the gene LMNA, which leads to the synthesis of a truncated precursor of lamin A known as progerin that lacks the target sequence for the
metallopotease FACE-1/ZMPSTE24 and remains constitutively farnesylated. The use of Face-1/Zmpste24-deficient mice allowed
us to demonstrate that accumulation of farnesylated prelamin A causes severe abnormalities of the nuclear envelope, hyper-activation
of p53 signalling, cellular senescence, stem cell dysfunction and the development of a progeroid phenotype. The reduction
of prenylated prelamin A levels in genetically modified mice leads to a complete reversal of the progeroid phenotype, suggesting
that inhibition of protein farnesylation could represent a therapeutic option for the treatment of progeria. However, we found
that both prelamin A and its truncated form progerin can undergo either farnesylation or geranylgeranylation, revealing the
need of targeting both activities for an efficient treatment of HGPS. Using Face-1/Zmpste24-deficient mice as model, we found that a combination of statins and aminobisphosphonates inhibits both types of modifications
of prelamin A and progerin, improves the ageing-like symptoms of these mice and extends substantially their longevity, opening
a new therapeutic possibility for human progeroid syndromes associated with nuclear-envelope defects. We discuss here the
use of this and other animal models to investigate the molecular mechanisms underlying accelerated ageing and to test strategies
for its treatment. 相似文献
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75.
Sylvanne M Daniels Carlos E Melendez-Peña Robert J Scarborough Aïcha Daher Helen S Christensen Mohamed El Far Damian FJ Purcell Sébastien Lainé Anne Gatignol 《BMC molecular biology》2009,10(1):38-13
Background
Dicer, Ago2 and TRBP are the minimum components of the human RNA-induced silencing complex (RISC). While Dicer and Ago2 are RNases, TRBP is the double-stranded RNA binding protein (dsRBP) that loads small interfering RNA into the RISC. TRBP binds directly to Dicer through its C-terminal domain. 相似文献76.
The cellular prion protein (PrPC) is a membrane-bound glycoprotein especially abundant in the central nervous system (CNS). The scrapie prion protein (PrPSc, also termed prions) is responsible of transmissible spongiform encephalopathies (TSE), a group of neurodegenerative diseases which affect humans and other mammal species, although the presence of PrPC is needed for the establishment and further evolution of prions.The present work compares the expression and localization of PrPC between healthy human brains and those suffering from Alzheimer disease (AD).In both situations we have observed a rostrocaudal decrease in the amount of PrPC within the CNS, both by immunoblotting and immunohistochemistry techniques. PrPC is higher expressed in our control brains than in AD cases. There was a neuronal loss and astogliosis in our AD cases. There was a tendency of a lesser expression of PrPC in AD cases than in healthy ones. And in AD cases, the intensity of the expression of the unglycosylated band is higher than the di- and monoglycosylated bands.With regards to amyloid plaques, those present in AD cases were positively labeled for PrPC, a result which is further supported by the presence of PrPC in the amyloid plaques of a transgenic line of mice mimicking AD.The work was done according to Helsinki Declaration of 1975, and approved by the Ethics Committee of the Faculty of Medicine of the University of Navarre.Key words: cellular prion protein, Alzheimer disease, transgenic mice 相似文献
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78.
Christina L. Hutson Jason A. Abel Darin S. Carroll Victoria A. Olson Zachary H. Braden Christine M. Hughes Michael Dillon Consuelo Hopkins Kevin L. Karem Inger K. Damon Jorge E. Osorio 《PloS one》2010,5(1)
Although monkeypox virus (MPXV) studies in wild rodents and non-human primates have generated important knowledge regarding MPXV pathogenesis and inferences about disease transmission, it might be easier to dissect the importance of virulence factors and correlates of protection to MPXV in an inbred mouse model. Herein, we compared the two clades of MPXV via two routes of infection in the BALB/c and C57BL/6 inbred mice strains. Our studies show that similar to previous animal studies, the Congo Basin strain of MPXV was more virulent than West African MPXV in both mouse strains as evidenced by clinical signs. Although animals did not develop lesions as seen in human MPX infections, localized signs were apparent with the foot pad route of inoculation, primarily in the form of edema at the site of inoculation; while the Congo Basin intranasal route of infection led to generalized symptoms, primarily weight loss. We have determined that future studies with MPXV and laboratory mice would be very beneficial in understanding the pathogenesis of MPXV, in particular if used in in vivo imaging studies. Although this mouse model may not suffice as a model of human MPX disease, with an appropriate inbred mouse model, we can unravel many unknown aspects of MPX pathogenesis, including virulence factors, disease progression in rodent hosts, and viral shedding from infected animals. In addition, such a model can be utilized to test antivirals and the next generation of orthopoxvirus vaccines for their ability to alter the course of disease. 相似文献
79.