全文获取类型
收费全文 | 784篇 |
免费 | 26篇 |
国内免费 | 3篇 |
出版年
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 12篇 |
2016年 | 21篇 |
2015年 | 24篇 |
2014年 | 20篇 |
2013年 | 47篇 |
2012年 | 44篇 |
2011年 | 34篇 |
2010年 | 19篇 |
2009年 | 24篇 |
2008年 | 49篇 |
2007年 | 43篇 |
2006年 | 40篇 |
2005年 | 54篇 |
2004年 | 42篇 |
2003年 | 44篇 |
2002年 | 37篇 |
2001年 | 9篇 |
2000年 | 14篇 |
1999年 | 14篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 17篇 |
1994年 | 6篇 |
1993年 | 10篇 |
1992年 | 15篇 |
1991年 | 13篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 7篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1968年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有813条查询结果,搜索用时 15 毫秒
21.
Hiroyoshi Ohashi 《Journal of plant research》1978,91(4):291-294
The taxonomic position ofEuchresta trifoliolata is discussed, and it is concluded that it is identical withE. japonica. Consequently,E. japonica can be considered to be discontinuously distributed between SW. Japan and S. China and represents a unique pattern of distribution,
which has not been known for the flora of Japan and China.E. japonica is also considered to represent a relic distribution pattern. 相似文献
22.
Hiroyoshi Hoshi Yuji Takagi Keizo Kobayashi Masakazu Onodera Taneaki Oikawa 《In vitro cellular & developmental biology. Animal》1991,27(7):578-584
Summary We have developed an improved serum-free medium to optimize the cell growth of bovine granulosa cells. The cells on collagen-coated
culture plates proliferated extensively in a nutrient medium supplemented with insulin, heparin binding growth factor-2 (HBGF-2),
lipoprotein, and bovine serum albumin (BSA). The cell doubling time at logarithmic phase and final cell density at confluent
cultures were equal to those of cultures grown in the presence of medium supplemented with optimal concentration (10%) of
fetal bovine serum (FBS). Whereas HBGF-2 or insulin alone had a small mitogenic effect of granulosa cells, lipoprotein or
BSA did not. When lipoprotein, BSA, or insulin was added together with HBGF-2, synergistic cell proliferation was observed
in all combinations. Insulin or lipoprotein had an additive mitogenic stimulation of these cells in the presence of BSA. After
granulosa cells were subcultivated in a serum-containing medium until three generations [8.5 cumulative population doubling
level (CPDL)], subsequent subcultivation of the cells in a complete serum-free medium could be achieved up to six generations
(14.4 CPDL). These results demonstrate that this serum-free medium can support the optimal cell growth and long-term subcultivation
of bovine granulosa cells. 相似文献
23.
Based on statistical variance as an index of electroencephalogram (EEG) parameters, we monitored slow-wave sleep in both humans and rats in real time and on-line with a widely used personal computer. This EEG variance method may be a useful tool to carry out biological rhythm research, including sleep studies. 相似文献
24.
Purification and characterization of a novel GTP-binding protein with a Mr value of 24,000 from rat liver 总被引:2,自引:0,他引:2
T Ohmori Y Takeyama T Ueda M Hiroyoshi H Nakanishi H Ohyanagi Y Saitoh Y Takai 《Biochemical and biophysical research communications》1990,169(2):816-823
About 15% of the total GTP-binding proteins (G proteins) of rat liver homogenate was found in the microsomes-Golgi complex fraction. From this fraction, we purified to near homogeneity and characterized a G protein with a Mr value of 24,000 (24K G). 24K G specifically bound guanosine 5'-(3-Q-thio) triphosphate (GTP gamma S), GTP and GDP with a Kd value for GTP gamma S of about 30 nM. 24K G bound maximally about 0.7 mol of GTP gamma S/mol of protein. 24K G hydrolyzed GTP to liberate Pi with a turnover number of about 0.008 min-1. 24K G was not copurified with the beta gamma subunit of heterotrimeric G proteins. The partial amino acid sequences of 24K G revealed that this protein was a novel small G protein. 相似文献
25.
Purification and characterization from bovine brain cytosol of proteins that regulate the GDP/GTP exchange reaction of smg p21s, ras p21-like GTP-binding proteins 总被引:16,自引:0,他引:16
T Yamamoto K Kaibuchi T Mizuno M Hiroyoshi H Shirataki Y Takai 《The Journal of biological chemistry》1990,265(27):16626-16634
Novel regulatory proteins for smg p21A and -B, ras p21-like GTP-binding proteins (G proteins) having the same putative effector domain as ras p21s, were purified to near homogeneity from bovine brain cytosol and characterized. These regulatory proteins, designated as GDP dissociation stimulator (GDS) 1 and -2, stimulated the dissociation of both [3H]GDP and [35S] guanosine 5'-(3-O-thio)triphosphate (GTP gamma S) from smg p21s to the same extent. smg p21 GDS1 and -2 also stimulated the binding of [35S]GTP gamma S to the GDP-bound form of smg p21s but not that to the guanine nucleotide-free form. These actions of smg p21 GDS1 and -2 were specific for smg p21s and inactive for other ras p21/ras p21-like G proteins including c-Ha-ras p21, rhoB p20, and smg p25A. Neither smg p21 GDS1 nor -2 stimulated the GTPase activity of smg p21s and by itself showed [35S]GTP gamma S-binding or GTPase activity. smg p21 GDS1 and -2 showed very similar physical and kinetic properties and were indistinguishable by peptide map analysis. The Mr values of smg p21 GDS1 and -2 were estimated to be about 53,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and from the S values, indicating that smg p21 GDS1 and -2 are composed of a single polypeptide without a subunit structure. smg p21 GDS1 and -2 were distinguishable from GTPase activating proteins (GAPs) for the ras and rho proteins, and smg p21B, and GDP dissociation inhibitors for smg p25A and the rho proteins previously identified in bovine brain cytosol. These results indicate that bovine brain contains regulatory proteins for smg p21s that stimulate the dissociation of GDP from and thereby the subsequent binding of GTP to smg p21s in addition to smg p21 GAP. It is likely that the conversion from the GDP-bound inactive form of smg p21s to the GTP-bound active form is regulated by smg p21 GDS and that its reverse reaction is regulated by smg p21 GAP. 相似文献
26.
Blood group H-active polysaccharide has been prepared from “smooth” strain Escherichia coli 2B-V by Freeman's method. a-Fucosidase derived from Bacillus fulminans caused the liberation of fucose from this polysaccharide, together with concomitant loss of blood group H activity. The results of quantitative microanalysis, borohydride reduction, the Morgan-Elson reaction and enzymic hydrolysis with β-galactosidase using isolated oligosaccharides obtained by partial acid hydrolysis indicated that the O-specific side chain of the polysaccharide has a pentasaccharide unit which is β-d-Gal-(1→3)-d-GalNAc-(1→3)-d-GalNAc-Fuc with a D -glucose residue bound at some undetermined point on this structure. It was considered that terminal non-reducing fucose of the polysaccharide was liberated by partial acid hydrolysis. 相似文献
27.
One of the constituents of polyoxin J, 2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid (3), has been synthesized stereoselectively from l-sorbopyranose. The amino acid function of 3 was formed in the final stage of the synthesis by reduction of the corresponding α-azido carboxylic acid. 相似文献
28.
Blood group H-active polysaccharide has been prepared from "smooth" strain Escherichia coli 2B-V by Freeman's method, alpha-Fucosidase derived from Bacillus fluminans caused the liberation of fucose from this polysaccharide, together with concomitant loss of blood group H activity. The results of quantitative microanalysis, borohydride reduction, the Morgan-Elson reaction and enzymic hydrolysis with betagalactosidase using isolated oligosaccharides obtained by partial acid hydrolysis indicated that the O-specific side chain of the polysaccharide has a pentassaccharide unit which is beta-D-Gal-(1 leads to 3)-D-GalNAc-(1 leads to 3)-D-GalNAc-Fuc with a D-glucose residue bound at some undetermined point on this structure. It was considered that terminal non-reducing fucose of the polysaccharide was liberated by partial acid hydrolysis. 相似文献
29.
Yoshikazu Hashida Katsuaki Takechi Tomomi Abiru Noriyuki Yabe Hiroaki Nagase Koro Hattori Susumu Takio Yoshikatsu Sato Mitsuyasu Hasebe Hirokazu Tsukaya Hiroyoshi Takano 《The Plant journal : for cell and molecular biology》2020,101(6):1318-1330
In Arabidopsis thaliana the ANGUSTIFOLIA (AN) gene regulates the width of leaves by controlling the diffuse growth of leaf cells in the medio‐lateral direction. In the genome of the moss Physcomitrella patens, we found two normal ANs (PpAN1‐1 and 1‐2). Both PpAN1 genes complemented the A. thaliana an‐1 mutant phenotypes. An analysis of spatiotemporal promoter activity of each PpAN1 gene, using transgenic lines that contained each PpAN1‐promoter– uidA (GUS) gene, showed that both promoters are mainly active in the stems of haploid gametophores and in the middle to basal region of the young sporophyte that develops into the seta and foot. Analyses of the knockout lines for PpAN1‐1 and PpAN1‐2 genes suggested that these genes have partially redundant functions and regulate gametophore height by controlling diffuse cell growth in gametophore stems. In addition, the seta and foot were shorter and thicker in diploid sporophytes, suggesting that cell elongation was reduced in the longitudinal direction, whereas no defects were detected in tip‐growing protonemata. These results indicate that both PpAN1 genes in P. patens function in diffuse growth of the haploid and diploid generations but not in tip growth. To visualize microtubule distribution in gametophore cells of P. patens, transformed lines expressing P. patens α‐tubulin fused to sGFP were generated. Contrary to expectations, the orientation of microtubules in the tips of gametophores in the PpAN1‐1/1‐2 double‐knockout lines was unchanged. The relationships among diffuse cell growth, cortical microtubules and AN proteins are discussed. 相似文献
30.
Abstract (1′R, 3′S and R, 5′S)-4′-Oxo-2′-oxabicyclo[3.1.0]hexan-3′-yl pyrimidines and purines were synthesized from ribonucleosides in 2-5 steps. The configurations of the base moieties in the cyclopropano keto-nucleosides were determined by NOE difference spectroscopy. 相似文献