全文获取类型
收费全文 | 1014篇 |
免费 | 59篇 |
国内免费 | 2篇 |
出版年
2023年 | 6篇 |
2021年 | 7篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2017年 | 9篇 |
2016年 | 18篇 |
2015年 | 30篇 |
2014年 | 30篇 |
2013年 | 34篇 |
2012年 | 35篇 |
2011年 | 57篇 |
2010年 | 34篇 |
2009年 | 27篇 |
2008年 | 47篇 |
2007年 | 48篇 |
2006年 | 30篇 |
2005年 | 48篇 |
2004年 | 43篇 |
2003年 | 51篇 |
2002年 | 46篇 |
2001年 | 49篇 |
2000年 | 31篇 |
1999年 | 25篇 |
1998年 | 16篇 |
1997年 | 9篇 |
1996年 | 6篇 |
1995年 | 9篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 30篇 |
1991年 | 25篇 |
1990年 | 30篇 |
1989年 | 26篇 |
1988年 | 18篇 |
1987年 | 15篇 |
1986年 | 14篇 |
1985年 | 18篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 14篇 |
1976年 | 6篇 |
1974年 | 6篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1969年 | 8篇 |
1965年 | 5篇 |
排序方式: 共有1075条查询结果,搜索用时 15 毫秒
21.
J Nishihira T Ishibashi M Sakai S Nishi T Kumazaki Y Hatanaka 《Biochemical and biophysical research communications》1992,189(2):1243-1251
1-Anilinonaphthalene-8-sulfonic acid (ANS) noncompetitively inhibited enzyme activity of glutathione S-transferase P for both glutathione and 1-chloro-2,4-dinitrobenzene (Ki = 30 microM). Dissociation constant for ANS.GST-P complex calculated from the binding study was 15 microM. From the similar values of the inhibition constant and the dissociation constant, it was concluded that specific ANS binding caused the loss of enzyme activity. In the protein structural analysis by circular dichroism, the secondary structures remarkably changed by ANS binding in accordance with the decrease of enzymatic activities. The conformational change of the protein and the decrease in enzymatic activity were reversed by dissociation of ANS. This fact strongly suggested that the enzymatic activity was regulated by a nonsubstrate hydrophobic ligand. 相似文献
22.
The effect of fructose on glycogen synthesis was examined in the perfused liver of starved rats. With increasing fructose concentration in the perfusate, glycogen synthesis and the % a form of glycogen synthase increased to a maximum at 2 mM and then decreased, progressively. The glucose 6-P level increased with the increase in fructose concentration. On the other hand, the ATP content was unchanged at a concentration of 2 mM or less and decreased at 3 mM or more. We also showed that the stimulation of glycogen synthesis by fructose at a concentration of 2 mM or less was due to activation of glycogen synthase by accumulated glucose 6-P and that ATP depletion at a concentration of 3 mM or more caused an increase in phosphorylase a and a decrease in glycogen synthase activity even in the presence of a high concentration of glucose 6-P. 相似文献
23.
Yoshihito Shirai Masaaki Yamaguchi Atsuko Kobayashi Akihiro Nishi Hisao Nakamura Hiroki Murakami 《Cytotechnology》1994,14(2):129-146
The growth yields for glucose and glutamine of murine hybridoma cells entrapped in collagen gel particles were examined during the growth phase. The immobilized hybridoma cells were cultivated in a fluidized bed fermenter where the medium was circulating to supply oxygen separately. Procedures to supply an alkaline solution for adjusting the pH level strongly affected the growth yields. A direct supply of the alkaline solution to the cultivation system reduced both the growth yields for glucose and glutamine, probably due to a local increase in pH level. On the other hand, when fresh medium in which the pH was adjusted to around 8.5 was added to the cultivation system, the growth yields were unchanged even at the same pH level as when direct alkaline supply was used. These results suggest that an indirect alkaline supply could be recommended to ajust the pH level when using medium-circulating-fermenters. 相似文献
24.
Yoko Ino Yutaro Yamaoka Kiho Tanaka Kei Miyakawa Mayuko Nishi Yasuyoshi Hatayama Hirokazu Kimura Yayoi Kimura Akihide Ryo 《Proteomics》2023,23(11):2200334
Peptide tag systems are a robust biophysical and biochemical method that is widely used for protein detection and purification. Here, we developed a novel tag system termed “HiP4” (histidine plus four amino acids) whose epitope sequence comprises only seven amino acids (HHHDYDI) that partially overlap with the conventional 6x histidine tag (6xHis-tag). We produced a monoclonal antibody against the HiP4 tag that can be used in multiple immunoassays with high specificity and affinity. Using this system, we developed a tandem affinity purification (TAP) and mass spectrometry (TAP-MS) system for comprehensive protein interactome analysis. The integrated use of nickel bead purification followed by HiP4 tag immunoprecipitation made it possible to reduce nonspecific binding and improve selectivity, leading to the recovery of previously unrecognized proteins that interact with hepatitis B virus X (HBx) protein or TAR DNA-binding protein 43 (TARDBP or TDP-43). Our results indicate that this system may be viable as a simple and powerful tool for TAP-MS that can achieve low background and high selectivity in comprehensive protein–protein interaction analyses. 相似文献
25.
Stem explants obtained from a mature tree of Ziziphus mauritiana Lamk were grown on modified Murashige and Skoog medium containing 3800 mg l-1 potassium nitrate, 2475 mg l-1 ammonium nitrate, 11 M benzyladenine and 0.5 M indole-3-acetic acid. During successive subcultures 15–20 shoots per inoculum were produced. Rooting was induced by pretreatment with 50 M indolebutyric acid or 1-naphthaleneacetic acid for 24 h followed by transfer to auxin-free White's medium. Plantlets grew well in a soil and vermiculite mixture.Abbreviations IAA
Indole-3-acetic acid
- NAA
1-naphthaleneacetic acid
- BA
benzyladenine
- MS
Murashige and Skoog 相似文献
26.
Shinji Hosoi Mitsuo Satoh Hiromasa Miyaji Tatsunari Nishi Tamio Mizukami Mamoru Hasegawa Seiga Itoh Tatsuya tamaoki 《Cytotechnology》1995,19(1):1-10
Pro-UKS1 was designed as a thrombin-resistant derivative of pro-urokinase (pro-UK) by introducing a glycosylation site using site-directed mutagenesis. An expression plasmid for pro-UKS1, pMo1UKS1SEd1-5, was constructed and introduced into Namalwa KJM-1 cells (Hosoiet al., 1988), and cells resistant to G418 and Methotrexate (MTX) were obtained. Amongst them, the highest pro-UKS1 producer (resistant to 500 nM of MTX), clone 41-8, was selected and further characterized. Clone 41-8 was cultured in serum-free ITPSGF medium (Hosoiet al., 1988). Under the conventional conditions, the concentration of pro-UKS1 reached 26 g ml–1. Addition of glucose and tri-iodothyronine (T3) improved productivity, and the maximal productivity of pro-UKS1 was 67 g ml–1 day–1. In this conditioned medium, content of pro-UKS1 was above 80% of total proteins.Abbreviations BSA
bovine serum albumin
- dhfr
dihydrofolate reductase
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- kb
kilobase pairs
- kDa
kilodaltons
- MTX
Methotrexate
- PBS
phosphate buffered saline
- pro-UK
pro-urokinase
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- T3
tri-iodothyronine
- Tween-PBS
phosphate buffered saline containing 0.05% Tween 80 相似文献
27.
Changes of an androgen-dependent nuclear protein during functional differentiation and by dedifferentiation of the dorsolateral prostate of rats 总被引:1,自引:0,他引:1
Y Matuo N Nishi Y Tanaka Y Muguruma K Tanaka Y Akatsuka S I Matsui A A Sandberg F Wada 《Biochemical and biophysical research communications》1984,118(2):467-473
In contrast with previous results that indicate that Saccharomyces cerevisiae fructose-1,6-bisphosphatase is a dimer of 56,000 molecular weight subunits, we find that the subunit Mr of the enzyme purified from baker's yeast is 40,000. The same subunit Mr was observed in immunoprecipitates of crude supernatants of baker's yeast and S. cerevisiae cultures, as well as in acid-extracts of cells detected by immunoblotting, suggesting that the native subunit indeed has a Mr of 40,000 and it has not been produced from a larger polypeptide. Complete immunoprecipitation of fructose-1,6-bisphosphatase activity with saturating concentrations of specific antibody suggests that there is only one fructose-1,6-bisphosphatase isozyme in S. cerevisiae. The Mr of the purified enzyme determined by size exclusion HPLC suggests that it has a tetrameric structure characteristic of fructose-1,6-bisphosphatases from a broad phylogenetic spectrum. 相似文献
28.
Hamster embryos were treated with various doses of NaNO2 in utero, by its oral administration to the mothers, and then the embryonic cells were examined for micronucleus formation, chromosomal aberrations, morphological or malignant transformation and drug-resistant mutations. For induction of resistant mutations, the cells were cultured in normal medium for 72 h, and then selected in media containing 8-azaguanine (10 or 20 microgram/ml) or 1 mM ouabain. This treatment with NaNO2 caused marked dose-dependent induction of 8-azaguanine- and ouabain-resistant mutations. Cultured embryonic fibroblasts in the resting state also showed a marked dose-dependent increase in micronucleus formation but not an increase in chromosomal aberrations. This treatment also caused morphological and neoplastic transformation of the cells. Transplacental oral treatment with DMN, as a positive control, caused changes of similar extent in biological effects of embryonic fibroblasts, and in addition it caused chromosomal aberrations in metaphase plates. On the contrary, transplacental oral application of NaNO2 did not induce any biological change in cultured embryonic fibroblasts. 相似文献
29.
Localization of intestinal sucrase-isomaltase complex on the microvillous membrane by electron microscopy using nonlabeled antibodies 总被引:2,自引:1,他引:1 下载免费PDF全文
Microvillous vesicles isolated from rabbit small intestine showed a trilaminar membrane with a rather smooth surface, which was apparently not affected by papain solubilizing sucrase-isomaltase complex or by trypsin unable to solubilize it. When microvilous vesicles or trysinized ones were incubated with immunoglobulin G against the sucrase-isomaltase complex or monovalent fragments therefrom, an apparently continuous electron-opaque layer approximately 180 A in width appeared around the external surface of vesicles. Such a layer was not formed on papainized vesicles. Microvillous vesicles and trypsinized ones negatively stained with phosphotungate showed a great number of particles protruding approximately 150 A from the membrane surface, but papainized vesicles did not. The particles existed close to one another and appeared to form a particulate layer 150 A in width on the surface. The antibodies, whether they were divalent or monovalent, increased the width of the layer to approximately 200 A and obscured the fine particulate structure of intact and trypsinized vesicles. Papainized vesicles retained their smooth surface upon interaction with antibodies. These results, together with those with the Triton-solubilized sucrase- isomaltase complex (Nishi and Takesue, 1978), J. Ultra-struct. Res., 62:1- 12), indicate not only that sucrase-isomaltase complexes are located close to one another on the membrane, but also that they or at least their protein portions protrude approximately 150 A from the surface of the trilaminar membrane. 相似文献
30.
Summary The location of leucine -naphthylamidase on the outer surface of the microvillous membrane of rabbit small intestine was examined by analyzing the interaction of antibodies against leucine -naphthylamidase or another microvillous enzyme, sucrase-isomaltase complex, with microvillous vesicles having different relative amounts of these enzymes, in respect to vesicle agglutination, inhibition of enzyme activity, and electron-microscopic morphology. The results obtained indicate that leucine -naphthylamidase, or at least its antigenic sites, protrude about 10 nm from the outer surface of the microvillous membrane. 相似文献