全文获取类型
收费全文 | 717篇 |
免费 | 35篇 |
学科分类
生物科学 | 752篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 3篇 |
2019年 | 7篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 26篇 |
2014年 | 20篇 |
2013年 | 49篇 |
2012年 | 62篇 |
2011年 | 61篇 |
2010年 | 33篇 |
2009年 | 37篇 |
2008年 | 53篇 |
2007年 | 39篇 |
2006年 | 54篇 |
2005年 | 43篇 |
2004年 | 48篇 |
2003年 | 24篇 |
2002年 | 36篇 |
2001年 | 1篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 6篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有752条查询结果,搜索用时 15 毫秒
51.
Masatomo So Yuto Kimura Keiichi Yamaguchi Toshihiko Sugiki Toshimichi Fujiwara Cesar Aguirre Kensuke Ikenaka Hideki Mochizuki Yasushi Kawata Yuji Goto 《Protein science : a publication of the Protein Society》2021,30(8):1701
Amyloid fibril formation is associated with various amyloidoses, including neurodegenerative diseases such as Alzheimer''s and Parkinson''s diseases. Amyloid fibrils form above the solubility of amyloidogenic proteins or peptides upon breaking supersaturation, followed by a nucleation and elongation mechanism, which is similar to the crystallization of solutes. Many additives, including salts, detergents, and natural compounds, promote or inhibit amyloid formation. However, the underlying mechanisms of the opposing effects are unclear. We examined the effects of two polyphenols, that is, epigallocatechin gallate (EGCG) and kaempferol‐7─O─glycoside (KG), with high and low solubilities, respectively, on the amyloid formation of α‐synuclein (αSN). EGCG and KG inhibited and promoted amyloid formation of αSN, respectively, when monitored by thioflavin T (ThT) fluorescence or transmission electron microscopy (TEM). Nuclear magnetic resonance (NMR) analysis revealed that, although interactions of αSN with soluble EGCG increased the solubility of αSN, thus inhibiting amyloid formation, interactions of αSN with insoluble KG reduced the solubility of αSN, thereby promoting amyloid formation. Our study suggests that opposing effects of polyphenols on amyloid formation of proteins and peptides can be interpreted based on the solubility of polyphenols. 相似文献
52.
Kensuke Miyamoto Toshihisa Kotake Makiko Sasamoto Marian Saniewski Junichi Ueda 《Journal of plant research》2010,123(3):363-370
The purpose of this study was to investigate the hormonal regulation of gummosis in grape hyacinth (Muscari armeniacum) bulbs, focusing especially on the chemical composition of the gums. The application of ethephon (2-chloroethylphosphonic
acid), an ethylene-releasing compound, at 1% and 2% (w/w) in lanolin as well as ethylene induced gummosis in the bulbs within
several days. Methyl jasmonate (JA-Me, 0.1–2% in lanolin) alone had no effect on gummosis. However, simultaneous application
of JA-Me and ethephon led to extreme stimulation of ethephon-induced gummosis. Ethephon-induced gummosis in the bulbs depended
on the maturation stage of the bulbs, increasing from April to July, but decreasing from August to September. Regardless of
the presence of JA-Me, the application of ethephon to the inflorescence axis of grape hyacinths did not induce gummosis. Gel
permeation chromatography analysis revealed that gums were homogenous polysaccharides with an average molecular mass of ca.
8.3 kDa. Analysis of the sugar composition of the gums after hydrolysis revealed that the molar ratio of Rha:Ara:Gal:GalA:GlcA
was 25:10:40:7:15. These results suggest that principal factors of gummosis as well as the chemical composition of gums differ
between species of bulbous plants. 相似文献
53.
54.
Casper C. Hoogenraad Ioana Popa Kensuke Futai Emma Sanchez-Martinez Phebe S. Wulf Thijs van Vlijmen Bjorn R. Dortland Viola Oorschot Roland Govers Maria Monti Albert J. R. Heck Morgan Sheng Judith Klumperman Holger Rehmann Dick Jaarsma Lukas C. Kapitein Peter van der Sluijs 《PLoS biology》2010,8(1)
The endosomal pathway in neuronal dendrites is essential for membrane receptor trafficking and proper synaptic function and plasticity. However, the molecular mechanisms that organize specific endocytic trafficking routes are poorly understood. Here, we identify GRIP-associated protein-1 (GRASP-1) as a neuron-specific effector of Rab4 and key component of the molecular machinery that coordinates recycling endosome maturation in dendrites. We show that GRASP-1 is necessary for AMPA receptor recycling, maintenance of spine morphology, and synaptic plasticity. At the molecular level, GRASP-1 segregates Rab4 from EEA1/Neep21/Rab5-positive early endosomal membranes and coordinates the coupling to Rab11-labelled recycling endosomes by interacting with the endosomal SNARE syntaxin 13. We propose that GRASP-1 connects early and late recycling endosomal compartments by forming a molecular bridge between Rab-specific membrane domains and the endosomal SNARE machinery. The data uncover a new mechanism to achieve specificity and directionality in neuronal membrane receptor trafficking. 相似文献
55.
Masato Ohtani Toshiaki Kondo Naoki Tani Saneyoshi Ueno Leong S. Lee Kevin K. S. Ng Norwati Muhammad Reiner Finkeldey Mohamad Na'iem Sapto Indrioko Koichi Kamiya Ko Harada Bibian Diway Eyen Khoo Kensuke Kawamura Yoshihiko Tsumura 《Molecular ecology》2013,22(8):2264-2279
Tropical rainforests in South‐East Asia have been affected by climatic fluctuations during past glacial eras. To examine how the accompanying changes in land areas and temperature have affected the genetic properties of rainforest trees in the region, we investigated the phylogeographic patterns of a widespread dipterocarp species, Shorea leprosula. Two types of DNA markers were used: expressed sequence tag‐based simple sequence repeats and chloroplast DNA (cpDNA) sequence variations. Both sets of markers revealed clear genetic differentiation between populations in Borneo and those in the Malay Peninsula and Sumatra (Malay/Sumatra). However, in the south‐western part of Borneo, genetic admixture of the lineages was observed in the two marker types. Coalescent simulation based on cpDNA sequence variation suggested that the two lineages arose 0.28–0.09 million years before present and that following their divergence migration from Malay/Sumatra to Borneo strongly exceeded migration in the opposite direction. We conclude that the genetic structure of S. leprosula was largely formed during the middle Pleistocene and was subsequently modified by eastward migration across the subaerially exposed Sunda Shelf. 相似文献
56.
Satoh H Shibahara K Tokunaga T Nishi A Tasaki M Hwang SK Okita TW Kaneko N Fujita N Yoshida M Hosaka Y Sato A Utsumi Y Ohdan T Nakamura Y 《The Plant cell》2008,20(7):1833-1849
Plastidial phosphorylase (Pho1) accounts for approximately 96% of the total phosphorylase activity in developing rice (Oryza sativa) seeds. From mutant stocks induced by N-methyl-N-nitrosourea treatment, we identified plants with mutations in the Pho1 gene that are deficient in Pho1. Strikingly, the size of mature seeds and the starch content in these mutants showed considerable variation, ranging from shrunken to pseudonormal. The loss of Pho1 caused smaller starch granules to accumulate and modified the amylopectin structure. Variation in the morphological and biochemical phenotype of individual seeds was common to all 15 pho1-independent homozygous mutant lines studied, indicating that this phenotype was caused solely by the genetic defect. The phenotype of the pho1 mutation was temperature dependent. While the mutant plants grown at 30 degrees C produced mainly plump seeds at maturity, most of the seeds from plants grown at 20 degrees C were shrunken, with a significant proportion showing severe reduction in starch accumulation. These results strongly suggest that Pho1 plays a crucial role in starch biosynthesis in rice endosperm at low temperatures and that one or more other factors can complement the function of Pho1 at high temperatures. 相似文献
57.
Cytochrome c-I which was involved in the decomposition of organic mercurials as an electron carrier was purified from the cell-free extract of the mercury-resistant strain, Pseudomonas K62, by means of (NH4)2SO4 precipitation and column chromatography on Sephadex G-150, DEAE-Sephadex and Sephadex G-75. The cytochrome was crystallized in a needle-like form. It showed absorption maxima at 550, 521, and 416.5 nm in the reduced form, and the pyridine ferrohemochrome had absorption maxima at 549, 520, and 413 nm, suggesting it to be a c-type cytochrome.
Cytochromes c prepared from type cultures of bacteria belonging to the genera Aeromonas, Micrococcus, Bacillus, Corynebacterium, Staphylococcus, Aerobacter, and Pseudomonas were all inactive with respect to the decomposition of phenylmercuric acetate. However, cytochrome c prepared from Pseudomonas CF, which was isolated from the activated sludge acclimatized with HgCl2 and phenylmercuric acetate, as well as the cytochrome c-I of Pseudomonas K62, were active in this respect. 相似文献
58.
59.
The potential use of alpha-cyclodextrin and its hydrophilic alpha-cyclodextrin derivatives (alpha-CyDs) as antagonists against lipopolysaccharide (LPS), which stimulates the nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) production as well as nuclear factor-kappaB (NF-kappaB) activation in macrophages was examined. Of three alpha-CyDs used in the present study, 2,6-di-O-methyl-alpha-CyD (DM-alpha-CyD) had greater inhibitory activity than did the other CyDs against NO and TNF-alpha production through an impairment of gene expression in macrophage cell lines and primary macrophages stimulated with LPS and lipid A in a concentration-dependent manner. Concomitantly, DM-alpha-CyD inhibited NF-kappaB translocation into nucleus. These inhibitory effects of DM-alpha-CyD could be attributed to the release of CD14 from lipid rafts caused by an efflux of phospholipids, but not cholesterol. These results suggest that DM-alpha-CyD may have promise as a potent and unique antagonist for excess activation of macrophages stimulated with LPS. 相似文献