全文获取类型
收费全文 | 820篇 |
免费 | 62篇 |
出版年
2022年 | 2篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 62篇 |
2012年 | 29篇 |
2011年 | 41篇 |
2010年 | 21篇 |
2009年 | 29篇 |
2008年 | 47篇 |
2007年 | 62篇 |
2006年 | 55篇 |
2005年 | 45篇 |
2004年 | 53篇 |
2003年 | 58篇 |
2002年 | 47篇 |
2001年 | 13篇 |
2000年 | 15篇 |
1999年 | 27篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 13篇 |
1995年 | 9篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 19篇 |
1991年 | 19篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1987年 | 3篇 |
1986年 | 11篇 |
1985年 | 5篇 |
1984年 | 10篇 |
1983年 | 12篇 |
1982年 | 12篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 4篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1969年 | 2篇 |
1967年 | 2篇 |
排序方式: 共有882条查询结果,搜索用时 15 毫秒
31.
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
32.
The kinetics of reversible unfolding and refolding by guanidine hydrochloride of the constant fragment of the immunoglobulin light chain are described. The kinetic measurements were made at pH 7.5 and 25 °C using tryptophyl fluorescence and farultraviolet circular dichroism.The kinetics of unfolding of the constant fragment showed two phases in the conformational transition zone and a single phase above the transition zone. A double-jump experiment confirmed the presence of two forms of the unfolded molecule. These results were thoroughly explained on the basis of the three-species mechanism, U1 U2 N, where U1 and U2 are the slow-folding and fast-folding species, respectively, of unfolded protein and N is native protein. The equilibrium constant for the process of U2 to U1 was estimated to be about 10 and was independent of the conditions of denaturation. These findings were consistent with the view that the U1 U2 reaction is proline isomerization. The rates of interconversion between N and U2 changed greatly with the concentration of guanidine hydrochloride. On the other hand, the refolding kinetics below the transition zone showed behavior unexpected from the three-species mechanism. Whereas the apparent rate constant of the slow phase of refolding was independent of the refolding conditions, its amplitude decreased markedly with the decrease in the final concentration of guanidine hydrochloride. On the basis of this and other results, formation of an intermediate during refolding was ascertained and the refolding kinetics were consistently explained in terms of a more general mechanism involving a kinetic intermediate probably containing non-native proline isomers. The intermediate seemed to have a folded conformation similar to native protein. Comparison of the refolding kinetics of the constant fragment with those of other domains of the immunoglobulin molecule suggested that Pro143 is responsible for the appearance of the slow phase. 相似文献
33.
34.
Kozo Matsumoto 《Biochemical genetics》1980,18(9-10):879-887
Two new esterase polymorphisms (Es-7 and Es-8) were identified in the testis homogenate of laboratory rats, Rattus norvegicus, by using discontinuous gradient polyacrylamide gel electrophoresis. Es-7 expressed two phenotypes: ES-7A (fast) and ES-7B (slow). Es-8, which migrated in the cathodal region rather than the ES-7 region, also expressed two phenotypes: ES-8A (fast) and ES-8B (slow). Linkage tests among Es-2, Es-7, and Es-8 were made from backcross progeny of the mating (LEJ/Hkm × T/Hok)F1 × LEJ/Hkm. One recombinant in 51 progeny tested was observed between Es-2 and Es-7; however, recombination between Es-2 and Es-8 was not observed in the same progeny. In addition, we show that the esterase polymorphisms of Es-5 in liver homogenate and Es-3 in small intestine homogenate are identical. 相似文献
35.
Isao Takata Kozo Yamamoto Tetsuya Tosa Ichiro Chibata 《Applied microbiology and biotechnology》1979,7(2):161-172
Summary To develop an efficient method for continuous production of L-malic acid from fumaric acid using immobilized microbial cells, screening of microorganisms having high fumarase activity was carried out and cultural conditions of selected microorganisms were investigated. As a result of screening microorganisms belonging to the genera Brevibacterium, Proteus, Pseudomonas, and Sarcina were found to produce fumarase in high levels. Among these microorganisms Brevibacterium ammoniagenes, B. flavum, Proteus vulgaris, and Pseudomonas fluorescens were further selected for their high fumarase levels in the cultivation on several media. These 4 microorganisms were entrapped into a k-carrageenan gel lattice, and the resultant immobilized B. flavum showed the highest fumarase activity and operational stability.Cultural conditions for the fumarase formation and the operational stability of fumarase activity of immobilized B. flavum are detailed. Productivity for L-malic acid using immobilized B. flavum with k-carrageenan was 2.3 fold of that using immobilized B. ammoniagenes with polyacrylamide.Presented at the Annual Meeting of the Agricultural Chemical Society of Japan, Nagoya, April 3, 1978 相似文献
36.
Plant growth-promoting activities of alkoxycarbonylisoureas in relation to their chemical structures
Masami Ogawa Kozo Oyamada Takashi Matsui Junzo Tobitsuka Yoshio Yamazaki 《Phytochemistry》1976,15(12):1829-1835
A number of alkoxycarbonylisourea derivatives were synthesized and their plant growth-promoting activities examined by the rice (Oryza sativa) seedling test. Isourea compounds with an appropriate substituent such as a halogen atom or a methyl, ethyl or methoxy group at the para-position on a benzene ring in 1-alkoxycarbonyl-2-alkyl-3-phenylcarbamoylisoureas promoted the growth of rice seedlings and acted as a highly active gibberellic acid-synergist when used in combination with gibberellic acid. The common structural requirements of isourea derivatives applied well for a growth promoter and a gibberellic acid-synergist. 相似文献
37.
The mechanism by which dihydroconiferyl alcohol (DCA) stimulatesindole-3-acetic acid (IAA)-induced elongation of cucumber hypocotylsections was studied. Although DCA did not affect the uptakeof IAA-5-3H by hypocotyl sections, the endogenous level of IAA-5-3Hin DCA-treated sections was much higher than in DCA untreatedones. IAA-5-3H in the incubation medium was degraded in thepresence of hypocotyl sections, and this degradation of IAAwas inhibited by DCA. An in vitro experiment with horseradishperoxidase revealed that DCA inhibited the IAA degrading activityof the oxidase, as did caffeic acid and ferulic acid. Theseresults suggested that DCA enhances IAA-induced cucumber hypocotylelongation by acting as an antioxidant of IAA. (Received June 4, 1975; ) 相似文献
38.
Ming-Chih Chiu Kei Nukazawa Thaddeus Carvajal Vincent H. Resh Bin Li Kozo Watanabe 《Ecography》2020,43(12):1891-1901
Different shapes of landscape boundaries can affect the habitat networks within them and consequently the spatial genetic-patterns of a metapopulation. In this study, we used a mechanistic framework to evaluate the effects of landscape shape, through watershed elongation, on genetic divergence among populations at the metapopulation scale. Empirical genetic data from four, sympatric stream-macroinvertebrates having aerial adults were collected from streams in Japan to determine the roles of species-specific dispersal strategies on metapopulation genetics. Simulation results indicated that watershed elongation allows the formation of river networks with fewer branches and larger topographic constraints. This results in decreased interpopulation connectivity but a lower level of spatial isolation of distal populations (e.g. those found in headwaters) occurring in the landscapes examined. Distal populations had higher genetic divergence when their downstream-biased dispersal (relative to upstream- and/or overland-biased dispersal) was high. This underscores the importance of distal populations influencing genetic divergence at the metapopulation scale for species having downstream-biased dispersal. In turn, lower genetic divergence was observed under watershed elongation when the genetic isolation of distal populations was decreased in such species. This strong association between landscape shape and evolutionary processes highlights the importance of natural, spatial architecture in assessing the effectiveness of conservation and management strategies. 相似文献
39.
Ryotaro Koike Mutsuki Amano Kozo Kaibuchi Motonori Ota 《Protein science : a publication of the Protein Society》2020,29(2):564-571
Phosphorylation is a major post‐translational modification that plays a central role in signaling pathways. Protein kinases phosphorylate substrates (phosphoproteins) by adding phosphate at Ser/Thr or Tyr residues (phosphosites). A large amount of data identifying and describing phosphosites in phosphoproteins has been reported but the specificity of phosphorylation is not fully resolved. In this report, data of kinase‐substrate pairs identified by the Kinase‐Interacting Substrate Screening (KISS) method were used to analyze phosphosites in intrinsically disordered regions (IDRs) of intrinsically disordered proteins. We compared phosphorylated and nonphosphorylated IDRs and found that the phosphorylated IDRs were significantly longer than nonphosphorylated IDRs. The phosphorylated IDR is often the longest IDR (71%) in a phosphoprotein when only a single phosphosite exists in the IDR, and when the phosphoprotein has multiple phosphosites in an IDR(s), the phosphosites are primarily localized in a single IDR (78%) and this IDR is usually the longest one (81%). We constructed a stochastic model of phosphorylation to estimate the effect of IDR length. The model that accounted for IDR length produced more realistic results when compared with a model that excluded the IDR length. We propose that the IDR length is a significant determinant for locating kinase phosphorylation sites in phosphoproteins. 相似文献
40.
Motoyuki Nakamura Yorihiko Koeda Fumitaka Tanaka Toshiyuki Onoda Kazuyoshi Itai Masaki Ohsawa Kozo Tanno Kiyomi Sakata Shinich Omama Yasuhiro Ishibashi Shinji Makita Mutsuko Ohta Kuniaki Ogasawara Takashi Komatsu Akira Okayama 《PloS one》2013,8(12)