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651.
Expression and activation of the vacuolar processing enzyme in Saccharomyces cerevisiae 总被引:1,自引:0,他引:1
Nagako Hiraiwa Mikio Nishimura Ikuko Hara-Nishimura 《The Plant journal : for cell and molecular biology》1997,12(4):819-829
Vacuolar processing enzymes (VPEs) are cysteine proteinases responsible for maturation of various vacuolar proteins in plants. A larger precursor to VPE synthesized on rough endoplasmic reticulum is converted to an active enzyme in the vacuoles. In this study, a precursor to castor bean VPE was expressed in a pep4 strain of the yeast Saccharomyces cerevisiae to examine the mechanism of activation of VPE. Two VPE proteins of 59 and 46 kDa were detected in the vacuoles of the transformant. They were glycosylated in the yeast cells, although VPE is not glycosylated in plant cells in spite of the presence of two N-linked glycosylation sites. During the growth of the transformant, the level of the 59 kDa VPE increased slightly until a rapid decrease occurred after 9 h. By contrast, the 46 kDa VPE appeared simultaneously with the disappearance of the 59 kDa VPE. Vacuolar processing activity increased with the accumulation of the 46 kDa VPE, but not of the 59 kDa VPE. The specific activity of the 46 kDa VPE was at a similar level to that of VPE in plant cells. The 46 kDa VPE instead of proteinase A mediated the conversion of procarboxypeptidase Y to the mature form. This indicates that proteinase A responsible for maturation of yeast vacuolar proteins can be replaced functionally by plant VPE. These findings suggest that an inactive VPE precursor synthesized on the endoplasmic reticulum is transported to the vacuoles in the yeast cells and then processed to make an active VPE by self-catalytic proteolysis within the vacuoles. 相似文献
652.
Takuo Nishida Hiroaki Matsumae Ikuko Machida Takeji Shibatani 《Biocatalysis and Biotransformation》1995,12(3):205-214
As a result of screening of microorganisms, Mucor ambiguus IFO 6742 was found to reduce methyl 2-chloro-3-(4-methoxyphenyl)-3-oxopropionate (2) to give methyl (2S,3R)-2-chloro-3-hydroxy-3-(4-methoxyphenyl)propionate [(2S,3R)-3] in good yield with high enantioselectivity. The resulting (2S, 3R)-3 was converted into methyl (2S,3R)-3-(4-methoxyphenyl)glycidate [(2S,3R)-4] by treatment with sodium methoxide. On the other hand, its enantiomer, (2R,3S)-4 was obtained by the Mitsunobu esterification of (2S,3R)-3 and subsequent treatment with sodium methoxide. Also (2R,3S)-4 was obtained by the treatment of (2RS,3S)-3, which was obtained from 2 by Trichoderma viride OUT 4642, with sodium methoxide. 相似文献
653.
Ikuko Yazaki 《Development, growth & differentiation》1993,35(6):671-682
A new substance (ES-1) which localizes on the ectodermal and espophageal epithelia of sea urchin embryos was identified by a monoclonal antibody, McA ES-1. McA ES-1 recognized a 175 KDa protein of fertilized and 200 KDa in proteins of unfertilized egg-cortices. By indirect fluorescent antibody staining, ES-1 was found on the plasma membrane of fertilized eggs and in the cortical region of unfertilized eggs. ES-1 was not contained in the cortical granules and remained fixed in the cortex after centrifugation of unfertilized eggs for 30 min at 20,000 g. The polarized localization of ES-1 on the apical surface of ectodermal epithelial cells continued to the metamorphosis. It disappeared from mesenchyme cells and other migrating cells of the gastrula, while ES-1 was reexpressed in the presumptive esophagus to be connected with ectodermal epithelium. This may suggest a functional significance of ES-1 in establishment of cell polarity in the epithelium of larvae. In metamorphosing larvae and adults, the apical localization of ES-1 could no longer be found, and it was found in coelomocytes. From these findings, it is concluded that ES-1 was a novel surface substance of embryos and is probably phagocytosed at metamorphosis. 相似文献
654.
Dense vesicles mediate the final step in the delivery of seedproteins to vacuoles in developing pumpkin (Cucurbita sp.) cotyledons.To explore the vesicle-mediated transport system that is targetedto vacuoles in plant cells, we isolated the dense vesicles andexamined then for the presence of guanine nucleotide-bindingproteins. GTP-binding proteins of 25 kDa and 27 kDa were detectedon the isolated vesicles. The 25-kDa protein had dithiothreitol-dependentGTP-binding activity, but binding of GTP by the 27-kDa proteinshowed no such dependence. Binding of [ 相似文献
655.
Sixty-seven isolates of the southern blight fungus from Japan were divided into five groups based on ITS-RFLP analysis of
nuclear rDNA. Morphological characters of sclerotia varied between groups. Three groups were reidentified asSclerotium rolfsii, and two resembledS. delphinii in RFLP patterns and/or in having large sclerotia and relatively low optimal growth temperature (28°C). Sclerotia of the
latter, however, varied in size according to temperature and became indistinguishable from those ofS. rolfsii at high temperatures. Hyphal anastomosis (imperfect fusion) was observed between different ITS-RFLP groups, as well as between
different isolates belonging to the same groups. These results indicate that populations of this fungus in Japan consists
of several different subgroups, although morphological differences are not always evident. 相似文献
656.
Induction of avascular yolk sac due to reduction of basic fibroblast growth factor by retinoic acid in mice 总被引:3,自引:0,他引:3
657.
We studied the ionic balance during diurnal changes in the levelsof accumulated malic acid and hydrogen ion in the vacuoles ofGraptopetalum paraguayense, a crassulacean acid metabolism (CAM)plant. There was a clear diurnal rhythm of the pH and the totalmalic acid content, but the amount of negative charges due tothe unprotonated carboxyl groups of malic acid remained approximatelyconstant. The negative charges were balanced by the positivecharges of cations, which were also constant throughout thediurnal CAM rhythm. The results gave evidence for the electroneutralityof the translocation of the malic acid and protons across thetonoplast membrane. (Received July 30, 1987; Accepted March 17, 1988) 相似文献
658.
Akira Sano Noriko Yamauchi Yasuo Kakimoto Osamu Komure Jun Kawai Fumitada Hazama Kazuyo Kuzume Nozomi Sano Ikuko Kondo 《Human genetics》1994,93(6):699-702
Anticipation refers to the progressively earlier onset and increase in disease severity in successive generations. We studied four families with hereditary dentatorubral-pallidoluysian atrophy (DRPLA), a neurodegenerative disease, and anticipation was present in the mode of inheritance. In subsequent generations DRPLA shows an earlier onset and more severe as well as additional symptoms. Older onset patients suffer from cerebellar ataxia with or without dementia, whereas younger onset patients present as progressive myoclonus epilepsy syndrome, which consists of mental retardation, dementia, and cerebellar ataxia as well as epilepsy and myoclonus. Anticipation with paternal transmission was significantly greater than with maternal transmission. 相似文献
659.
Autoantibodies recognizing proteins copurified with PCNA in patients with connective tissue diseases
Ken Takeuchi Kazuhiko Kaneda Ikuko Kawakami Yoshinari Takasaki Hiroshi Hashimoto 《Molecular biology reports》1996,23(3-4):243-246
Objective. Proliferating cell nuclear antigen (PCNA), one of the target antigen recognized by lupus sera, has been reported to be present as a subnuclear multi-peptide complex. But autoantibodies reacting with components of PCNA complex are poorly understood. To study the specificity of those autoantibodies, immunoreactivities of autoimmune sera against purified PCNA antigen were studied. Methods. PCNA antigens were purified from rabbit thymus extract by affinity column using murine monoclonal antibodies (mAbs) to PCNA, TOB7, TO17 and TO30. Immunoreactivities of autoimmune sera against purified PCNA were analyzed by WB. Results. PCNA antigen purified by serum AK predominantly showed a 34 kD band specific for PCNA in SDS-PAGE. When antigens were purified by anti-PCNA mAb TOB7 and TO30 which are known to be targeting different epitopes on PCNA antigen, SDS-PAGE analysis showed various mol. wt of proteins in addition to the 34 kD PCNA while both AK and mAbs reacted only with 34 kD PCNA in WB. In WB using PCNA purified by TOB7, various immunoreactivities were observed at 150, 66, 58, 48, 45, 37, 32 and 16 kDa in sera from patients with connective tissue diseases. Conclusions. These results suggested that many of the proteins copurified with PCNA were also targets of autoimmune responses and these autoantibody experssion may be induced through antigen-driven mechanisms.Abbreviations mAb
monoclonal antibody
- PCNA
proliferating cell nuclear antigen
- PCNA/AK
PCNA affinity purified by antibodies from patient serum AK
- PCNA/TO30
PCNA purfied by mAb TO30
- PCNA/TOB7
PCNA purified by mAb TOB7
- SLE
systemic lupus erythematosus 相似文献
660.
Yumi Sugimoto Jun Yamada Ikuko Kimura Yoshiko Watanabe Kazuyoshi Horisaka 《Neurochemical research》1994,19(1):19-22
Effects of tryptamine on tolbutamide-induced hypoglycemia were investigated in mice. Tryptamine significantly inhibited hypoglycemia elicited by tolbutamide. The inhibitory effects of tryptamine were strongly blocked by the 5-HT1 and 5-HT2 receptor antagonist methysergide and the 5-HT2 receptor antagonist ketanserin, while the 5-HT3 receptor antagonist ICS 205–930 was without effect. Tryptamine induced hyperglucagonemia in tolbutamide-treated mice, and this effect elicited by tryptamine was strongly inhibited by the 5-HT2 receptor antagonist ketanserin. These results suggest that the inhibitory effects of tryptamine on tolbutamide-induced hypoglycemia are mediated by 5-HT2 receptors and that tryptamine is involved in glucagon release. 相似文献