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排序方式: 共有501条查询结果,搜索用时 12 毫秒
81.
82.
Hayakawa A Kawamoto Y Nakajima H Sakai J Takasawa R Nakashima I Magae J Tanuma S 《Apoptosis : an international journal on programmed cell death》2008,13(4):523-530
Vinorelbine is a chemotherapeutic vinca alkaloid clinically prescribed for non-small cell lung cancer and breast cancer. Here we studied the mechanism for vinorelbine-induced
apoptosis in a human T-cell lymphoma. Although vinorelbine induces DNA fragmentation that is inhibited by specific peptide
inhibitors for caspases-9 and -3 in Jurkat cells, caspase-8 deficiency retards vinorelbine-induced apoptosis. Activation of
caspase-8 is also observed in vinorelbine-treated cells, and the activity is diminished when the caspase-3 activity is blocked
by a specific peptide inhibitor, Ac-DNLC-CHO. Blocking of the Fas receptor with an antagonistic anti-Fas antibody does not
affect vinorelbine-induced DNA fragmentation. These results suggest that vinorelbine-induced apoptosis is enhanced by the
activation of caspase-8 via caspase-9-mediated activation of caspase-3, but not through a Fas-triggered signal. Western blotting
suggests that vinorelbine cleaves caspase-3, -9 and -8 and reduces the amount of mitochondrial cytochrome c. Caspase-8 deficiency suppresses all of these events. A downstream substrate for caspase-8, Bid, is also cleaved in vinorelbine-treated
cells, but the Bid truncation is also observed in caspase-8-deficient Jurkat cells. Importantly, recombinant caspases-3 and
-9, as well as caspase-8, directly cleaves recombinant Bid in vitro. These results suggest that caspases-3 and -9 participate
in Bid truncation, indicating a new mechanism for vinorelbine-induces apoptosis. 相似文献
83.
Caterina Minelli Akemi Kikuta Nataliya Tsud Michael D Ball Akiko Yamamoto 《Journal of nanobiotechnology》2008,6(1):3
Background
Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction. 相似文献84.
Bacteria living in soil collected from a rice paddy in Fukuoka, Japan, were examined by electron microscopy using a freeze-substitution fixation method. Most of the observed bacteria could be categorized, based on the structure of the cell envelope and overall morphology, into one of five groups: (i) bacterial spore; (ii) Gram-positive type; (iii) Gram-negative type; (iv) Mycobacterium like; and (v) Archaea like. However, a few of the bacteria could not be readily categorized into one of these groups because they had unique cell wall structures, basically resembling those of Gram-negative bacteria, but with the layer corresponding to the peptidoglycan layer in Gram-negative bacteria being extremely thick, like that of the cortex of a bacterial spore. The characteristic morphological features found in many of these uncultured, soil-dwelling cells were the nucleoid being in a condensed state and the cytoplasm being shrunken. We were able to produce similar morphologies in vitro using a Salmonella sp. by culturing under low-temperature, low-nutrient conditions, similar to those found in some natural environments. These unusual morphologies are therefore hypothesized to be characteristic of bacteria in resting or dormant stages. 相似文献
85.
Fujibayashi A Taguchi T Misaki R Ohtani M Dohmae N Takio K Yamada M Gu J Yamakami M Fukuda M Waguri S Uchiyama Y Yoshimori T Sekiguchi K 《Cell structure and function》2008,33(1):35-50
RME-8 is a DnaJ-domain-containing protein that was first identified in Caenorhabditis elegans as being required for uptake of yolk proteins. RME-8 has also been identified in other species, including flies and mammals, and the phenotypes of their RME-8 mutants suggest the importance of this protein in endocytosis. In the present study, we cloned human RME-8 (hRME-8) and characterized its biochemical properties and functions in endocytic pathways. hRME-8 was found to be a peripheral protein that was tightly associated with the membrane via its N-terminal region. It partially colocalized with several early endosomal markers, but not with late endosomal markers, consistent with observations by immunoelectron microscopy. When cells were transfected with a panel of dominant-active Rab proteins, hRME-8 was confined to large vacuoles induced by expression of Rab5aQ79L, but not by Rab7Q67L. Expression of C-terminally-truncated hRME-8 mutants led to the formation of large puncta and vacuoles, and compromised endocytic pathways through early endosomes, i.e., recycling of transferrin and degradation of epidermal growth factor. Taken together, these results indicate that hRME is primarily involved in membrane trafficking through early endosomes, but not through degradative organelles, such as multivesicular bodies and late endosomes. 相似文献
86.
Some sensors of extracellular signaling molecules such as Notch and sterol response element binding protein (SREBP) receive ligand-induced intra-membrane proteolysis followed by nuclear translocation of their cytoplasmic domains to regulate gene expression programs in the nucleus. It has not been extensively examined whether ligand-induced intra-membrane proteolysis of type I cytokine receptors and nuclear translocation of cytoplasmic domains occur. Here, by using a sensitive reporter system, we examined this possibility for the interleukin-2 (IL-2) receptor (IL-2R) β-chain (IL-2Rβ) and the IL-15 receptor (IL-15R) α-chain (IL-15Rα). Flowcytometric analysis revealed that ligand stimulation does not induce nuclear translocation of their cytoplasmic domains. In addition, overexpression of the cytoplasmic domain of the common cytokine receptor γ-chain (γc) in an IL-2R-reconstituted Ba/F3-derived cell line did not affect any biological responses including cell survival, disproving potential roles of the cleaved cytoplasmic domain of γc as a signal transducer. Collectively, these results indicated that potential nuclear function of cleaved type I cytokine receptor subunits is not plausible. 相似文献
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89.
Sumiyo Morita Akemi Hara Itaru Kojima Takuro Horii Mika Kimura Tadahiro Kitamura Takahiro Ochiya Katsumi Nakanishi Ryo Matoba Kenichi Matsubara Izuho Hatada 《PloS one》2009,4(1)
Dicer1, an essential component of RNA interference and the microRNA pathway, has many important roles in the morphogenesis of developing tissues. Dicer1 null mice have been reported to die at E7.5; therefore it is impossible to study its function in adult tissues. We previously reported that Dicer1-hypomorphic mice, whose Dicer1 expression was reduced to 20% in all tissues, were unexpectedly viable. Here we analyzed these mice to ascertain whether the down-regulation of Dicer1 expression has any influence on adult tissues. Interestingly, all tissues of adult (8–10 week old) Dicer1-hypomorphic mice were histologically normal except for the pancreas, whose development was normal at the fetal and neonatal stages; however, morphologic abnormalities in Dicer1-hypomorphic mice were detected after 4 weeks of age. This suggested that Dicer1 is important for maintaining the adult pancreas. 相似文献
90.