全文获取类型
收费全文 | 229篇 |
免费 | 20篇 |
专业分类
249篇 |
出版年
2021年 | 1篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 3篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 20篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 23篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1974年 | 3篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有249条查询结果,搜索用时 15 毫秒
81.
Chiharu Sadakane Shuichi Muto Koji Nakagawa Shunsuke Ohnishi Yayoi Saegusa Miwa Nahata Tomohisa Hattori Masahiro Asaka Hiroshi Takeda 《Biochemical and biophysical research communications》2011,(3):506
Rikkunshito (RKT), a Japanese traditional medicine, has been shown to stimulate food intake in rats with cisplatin-induced anorexia; however, the underlying mechanisms remain unknown. In this study, we investigated whether RKT is involved in the degradation of peripheral ghrelin. RKT inhibited decreases in plasma ghrelin level and enhanced acyl- to desacyl-ghrelin (A/D) ratio in cisplatin-treated rats. Several components of RKT demonstrated inhibitory activity against ghrelin deacylating enzymes. In addition, 10-gingerol, a component of RKT, inhibited exogenous ghrelin deacylation. Therefore, RKT may enhance plasma acyl-ghrelin level, at least in part, by inhibiting the circulating ghrelin degrading enzyme. 相似文献
82.
Kazuhiko Higashida Sang Hyun Kim Su Ryun Jung Meiko Asaka John O. Holloszy Dong-Ho Han 《PLoS biology》2013,11(7)
It has been reported that feeding mice resveratrol activates AMPK and SIRT1 in skeletal muscle leading to deacetylation and activation of PGC-1α, increased mitochondrial biogenesis, and improved running endurance. This study was done to further evaluate the effects of resveratrol, SIRT1, and PGC-1α deacetylation on mitochondrial biogenesis in muscle. Feeding rats or mice a diet containing 4 g resveratrol/kg diet had no effect on mitochondrial protein levels in muscle. High concentrations of resveratrol lowered ATP concentration and activated AMPK in C2C12 myotubes, resulting in an increase in mitochondrial proteins. Knockdown of SIRT1, or suppression of SIRT1 activity with a dominant-negative (DN) SIRT1 construct, increased PGC-1α acetylation, PGC-1α coactivator activity, and mitochondrial proteins in C2C12 cells. Expression of a DN SIRT1 in rat triceps muscle also induced an increase in mitochondrial proteins. Overexpression of SIRT1 decreased PGC-1α acetylation, PGC-1α coactivator activity, and mitochondrial proteins in C2C12 myotubes. Overexpression of SIRT1 also resulted in a decrease in mitochondrial proteins in rat triceps muscle. We conclude that, contrary to some previous reports, the mechanism by which SIRT1 regulates mitochondrial biogenesis is by inhibiting PGC-1α coactivator activity, resulting in a decrease in mitochondria. We also conclude that feeding rodents resveratrol has no effect on mitochondrial biogenesis in muscle. 相似文献
83.
84.
Shigeomi Ushijima Tadanobu Nakadai Kinji Uchida 《Bioscience, biotechnology, and biochemistry》2013,77(10):2781-2786
A new breeding process for Aspergillus sojae involving protoplast fusion was studied to obtain more desirable koji-molds for soy-sauce production, especially as to their enzyme productivities. A pair of double-marker mutants with characteristic enzyme-productivities, derived from genealogically unrelated A. sojae cultures, were fused by means of the protoplast fusion technique. The fusants were UV-treated, and stable heterozygous diploids were obtained. Further improvement of their enzyme-productivities was attempted using two approaches. Through the usual mutation of the heterozygous diploids, the activities of protease and glutaminase were simultaneously improved to a certain extent. Through the haploidization of the heterozygous diploids with benomyl or p-fluorophenylalanine (FPA), some haploids considered phenotypically to be recombinants were segregated, in addition to a large number of haploids that had reverted to the original double marker mutants. On screening these haploid-recombinants, the authors obtained a few more excellent recombinants, as to their enzyme productivities, that is, strains producing as much protease as the hyper-protease producer and producing almost as much glutaminase as the hyper- glutaminase producing parent. It has been shown that mutation or especially haploidization of heterozygous diploids produced by cell-fusion could be a very useful technique for the breeding of new industrial koji-molds. 相似文献
85.
Prolactin-releasing peptide (PrRP) was first isolated from bovine hypothalamus as an orphan G-protein-coupled receptor using the strategy of reverse pharmacology. The initial studies showed that PrRP was a potent and specific prolactin-releasing factor. Morphological and physiological studies, however, indicated that PrRP may play a wide range of roles in neuroendocrinology other than prolactin release, i.e., metabolic homeostasis, stress responses, cardiovascular regulation, gonadotropin secretion, GH secretion and sleep regulation. This review will provide the current knowledge of PrRP, especially its roles in energy metabolism and stress responses. 相似文献
86.
87.
Borate-Rhamnogalacturonan II Bonding Reinforced by
Ca2+ Retains Pectic Polysaccharides in Higher-Plant Cell
Walls 下载免费PDF全文
The extent of in vitro formation of
the borate-dimeric-rhamnogalacturonan II (RG-II) complex was stimulated
by Ca2+. The complex formed in the presence of
Ca2+ was more stable than that without Ca2+. A
naturally occurring boron (B)-RG-II complex isolated from radish
(Raphanus sativus L. cv Aokubi-daikon) root contained
equimolar amounts of Ca2+ and B. Removal of the
Ca2+ by
trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic
acid induced cleavage of the complex into monomeric RG-II. These data
suggest that Ca2+ is a normal component of the B-RG-II
complex. Washing the crude cell walls of radish roots with a 1.5%
(w/v) sodium dodecyl sulfate solution, pH 6.5, released 98% of the
tissue Ca2+ but only 13% of the B and 22% of the pectic
polysaccharides. The remaining Ca2+ was associated with
RG-II. Extraction of the sodium dodecyl sulfate-washed cell walls with
50 mm
trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetic
acid, pH 6.5, removed the remaining Ca2+, 78%
of B, and 49% of pectic polysaccharides. These results suggest that
not only Ca2+ but also borate and Ca2+
cross-linking in the RG-II region retain so-called chelator-soluble
pectic polysaccharides in cell walls.Boron (B) is an essential element for higher plant growth,
although its primary function is not known (Loomis and Durst, 1992).
Determining the sites of B in cells is required to identify its
function. In cultured tobacco cells more than 80% of cellular B is in
the cell wall (Matoh et al., 1993), whereas the membrane fraction
(Kobayashi et al., 1997) and protoplasts (Matoh et al., 1992) do not
contain a significant amount of B. In radish (Raphanus
sativus L. cv Aokubi-daikon) root cell walls, B cross-links two
RG-II regions of pectic polysaccharides through a borate-diol ester
(Kobayashi et al., 1995, 1996). The association of B with RG-II has
been confirmed in sugar beet (Ishii and Matsunaga, 1996), bamboo
(Kaneko et al., 1997), sycamore and pea (O''Neill et al., 1996), and
red wine (Pellerin et al., 1996). In cultured tobacco cells the B
associated with RG-II accounts for about 80% of the cell wall B
(Kobayashi et al., 1997) and RG-II may be the exclusive carrier of B in
higher plant cell walls (Matoh et al., 1996). Germanic acid, which
partly substitutes for B in the growth of the B-deprived plants (Skok,
1957), also cross-links two RG-II chains (Kobayashi et al., 1997).
These results suggest that the physiological role of B is to cross-link
cell wall pectic polysaccharides in the RG-II region and thereby form a
pectic network.It is believed that in the cell wall pectic polysaccharides are
cross-linked with Ca2+, which binds to carboxyl
groups of the polygalacturonic acid regions (Jarvis, 1984). Thus, the
ability of B and Ca2+ to cross-link cell wall
pectic polysaccharides needs to be evaluated. In this report we
describe the B-RG-II complex of radish root and the role of B-RG-II and
Ca2+ in the formation of a pectic
network. 相似文献
88.
Hayashi T Juliet PA Miyazaki A Ignarro LJ Iguchi A 《Biochimica et biophysica acta》2007,1772(3):364-372
Atherosclerosis, an inflammatory disease, is closely associated with hyperglycemia, major sign of diabetes mellitus. Caveolae are vesicular invaginations of the plasma membrane that mediate the intracellular transport of lipids such as cholesterol. We evaluated the relationship between the expression of caveolin-1 and the number of caveolae in macrophages under conditions of high glucose concentration. Increased superoxide production, induction of inducible nitric oxide synthase (iNOS), and decreased caveolin-1 were observed in a concentration-dependent manner in THP-1 derived macrophages with high glucose concentrations. Mannitol, used as an osmotic control, showed no effects. Furthermore, co-localization of the NADPH oxidase component, p47(phox), and caveolin was confirmed by confocal microscopy. An atomic force microscopy (AFM) study showed that high glucose concentrations reduced the number and size of the caveolae. The percentage of cells with fragmented DNA was increased in cells grown in hyperglycemic media. Taken together, high glucose concentrations suppress the levels of caveolin-1 expression and reduce the number of caveolae. This might be due to the actions of superoxide via the activation of NADPH oxidase by translocation of its component and uncoupling of induced iNOS in macrophages. Furthermore, the apoptosis of macrophages might occur with high glucose concentrations, leading to the spreading of lipids from macrophages into intracellular spaces in the vessel wall. 相似文献
89.
90.
Matsuoka H Honzawa S Takahashi A Yoshikawa H Watanabe E Watanabe T Ozawa Y Yamada Y Iizuka T Uda Y 《Bioscience, biotechnology, and biochemistry》2008,72(9):2262-2268
The photostability of (E)-2-[3-(2-thioxopyrrolidin-3-ylidene)methyl]-tryptophan ((E)-TPMT), the main yellow pigment in salted radish, was studied. First we analyzed the photoproduct generated from (E)-TPMT under longwave UV irradiation. On the basis of NMR spectroscopy, the photoproduct was identified as Z-configurated TPMT, and isomerization from the Z- to the E-form was reversibly induced by Vis-light irradiation. The optimum wavelength for isomerization from the E- to the Z-form was 360-380 nm, and that for isomerization from the Z- to the E-form was 440-460 nm. The E/Z-ratios in the photostationary state under UV- and Vis-light irradiation conditions were approximately 0.95:1 and 26:1 respectively. The (Z)-isomer was more sensitive to light irradiation than the (E)-isomer in the quantum yield measurement. Yellowing was dependent on the ratio of the (Z)-isomer, because the b(*) and chroma value rose with increases in the (Z)-isomer by the colorimeters. Hence, it is possible that the formation of the (Z)-isomer contribute to the yellow color of takuan-zuke during long salting and fermentation. 相似文献