全文获取类型
收费全文 | 1123篇 |
免费 | 70篇 |
出版年
2022年 | 2篇 |
2021年 | 11篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 14篇 |
2017年 | 6篇 |
2016年 | 15篇 |
2015年 | 27篇 |
2014年 | 45篇 |
2013年 | 62篇 |
2012年 | 68篇 |
2011年 | 72篇 |
2010年 | 44篇 |
2009年 | 42篇 |
2008年 | 63篇 |
2007年 | 95篇 |
2006年 | 74篇 |
2005年 | 82篇 |
2004年 | 107篇 |
2003年 | 73篇 |
2002年 | 62篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 18篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 10篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 3篇 |
排序方式: 共有1193条查询结果,搜索用时 31 毫秒
991.
992.
Toshihiro Yasuda Misuzu Ueki Haruo Takeshita Junko Fujihara Kaori Kimura-Kataoka Reiko Iida Etsuko Tsubota Mikiko Soejima Yoshiro Koda Hideaki Kato Arturo Panduro 《The international journal of biochemistry & cell biology》2010,42(7):1216-1225
A reduction of deoxyribonuclease I (DNase I) activity levels in the serum of patients with autoimmune diseases has been reported. The objectives of this study were to clarify genetic and biochemical aspects of 12 non-synonymous SNPs in the human gene (DNASE1), potentially giving rise to an alteration in the in vivo DNase I activity levels. Genotyping of all the non-synonymous SNPs was performed in healthy subjects of three ethnic groups including 15 populations using newly developed methods. Among them, only four SNPs, R-21S, Y95S, G105R, and Q222R were polymorphic in all or some populations; Asian group showed a relatively low genetic diversity of these SNPs. Furthermore, the distribution pattern of the common SNP Q222R was classified into three ethnic groups. The activity levels of the amino acid-substituted DNase I forms derived from SNPs R-21S, G105R, P132A, and P197S were significantly high compared with that of the wild-type; the polymorphic SNPs R-21S and G105R gave rise to a high activity-harboring DNase I isoform. On the other hand, activity levels from Q35H, R85G, V89M, C209Y, Q222R, and A224P were significantly low, but these SNPs, except Q222R, were not distributed in any of the populations. However, since these SNPs may produce potentially low levels of in vivo DNase I activity, a minor allele in each SNP will be served as a genetic risk factor for autoimmune diseases. These findings on non-synonymous SNPs in DNASE1 may provide a biochemical-genetic basis for the clarification of a possible relationship between DNase I and the diseases. 相似文献
993.
994.
Marubuchi S Okuda T Tagawa K Enokido Y Horiuchi D Shimokawa R Tamura T Qi ML Eishi Y Watabe K Shibata M Nakagawa M Okazawa H 《Journal of neurochemistry》2006,99(1):70-83
Hepatoma-derived growth factor (HDGF) is a nuclear protein homologous to the high-mobility group B1 family of proteins. It is known to be released from cells and to act as a trophic factor for dividing cells. In this study HDGF was increased in spinal motor neurons of a mouse model of motor neuron degeneration, polyglutamine-tract-binding protein-1 (PQBP-1) transgenic mice, before onset of degeneration. HDGF promoted neurite extension and survival of spinal motor neurons in primary culture. HDGF repressed cell death of motor neurons after facial nerve section in newborn rats in vivo. We also found a significant increase in p53 in spinal motor neurons of the transgenic mice. p53 bound to a sequence in the upstream of the HDGF gene in a gel mobility shift assay, and promoted gene expression through the cis-element in chloramphenicol acetyl transfer (CAT) assay. Finally, we found that HDGF was increased in CSF of PQBP-1 transgenic mice. Collectively, our results show that HDGF is a novel trophic factor for motor neurons and suggest that it might play a protective role against motor neuron degeneration in PQBP-1 transgenic mice. 相似文献
995.
We applied a flow cytometry apparatus (FCM) to differenciating Exophiala dermatitidis, E. moniliae and E. jeanselmei from each other. The wavelength of the argon laser emitted from the FCM was 488 nm and the aperture of nozzle from which the stream of fluid containing single cells was blown out was 100 m. By irradiating the stream with laser by either the forward light scatter (FLS) or by the perpendicular light scattr (PLS), we were able to get two pieces of informations. Histograms displayed by the FLS indicate the cell size, while dot displays by the PLS reflect the cell structure. As a result, E. dermatitidis was clearly differenciated from either E. moniliae or E. jeanselmei by their histograms by FLS. In addition, dot displays by the PLS differenciated E. moniliae from E. jeanselmei.In conclusion, flow cytometry is available for differenciating E. dermatitidis, E. moniliae and E. jeanselmei from each other. 相似文献
996.
Intracellular Ca2+ concentration regulating the cytoplasmicstreaming in Vallisneria mesophyll cells was estimated. Theleaf segment was cut open at the middle of the mesophyll celllayers and the exposed mesophyll cells were treated with testsolutions of various Ca2+ concentrations in the dark. This allowedA23187
[GenBank]
, a calcium ionophore, to exert its full effect on thecell membrane. The streaming was induced or maintained in solutions which containedCa2+ at lower than 106M. However, Ca2+ at concentrationshigher than 105M had a definite, inhibitory effect. Theinduction and cessation of streaming could be repeated by alternatelychanging the solutions. (Received March 14, 1986; Accepted May 15, 1986) 相似文献
997.
Izumi Nakashima Tomoaki Yoshida Takashi Yokochi Kimiko Ohashi Fumihiko Nagase Ken-ichi Isobe Yoshinori Hasegawa Ko-ichi Ando Reiko Inagi 《Immunogenetics》1986,24(1):32-40
Immunogenicity for T cell-independent B-cell response assessed by splenic plaque-forming cell (PFC) response and cell-surface expression measured by laser flow cytometry of various class I H-2 antigens on mouse red blood cells (RBC) were compared. It was found that the order of magnitude of both immunogenicity and cell-surface expression on RBC is H-2Dd H-2Db > H-2Kd, H-2Kb. Furthermore, H-2d public antigens and H-2Ld antigens were neither immunogenic nor easily demonstrable on RBC. These findings contrasted with poor immunogenicity for PFC response (Nakashima et al. 1982, 1983) and proportionally strong expression of H-2 antigens on lymphoid cells. Immunogenicity and cell-surface expression of H-2Dd antigen on RBC were not shown to be controlled by the action of genes outside H-2D. It was therefore suggested that a number of H-2 antigens, including H-2Kd private, H-2Kb private, and H-2d public specificities are at least functionally defective on RBC. This is possibly due to the structural characteristics of the antigens. Since immunogenicity and cell-surface expression were in parallel, the expression of H-2 antigens on RBC must be dictated by a subset of B cells whose activity was assessed by PFC response. This finding supports the view that the H-2 molecules display a new category of activity which is different from their ability to activate T cells and depends on their expression on RBC. 相似文献
998.
Fluorescence spectra of the pigment system at 196°Cin membrane fragments of Anabaena variabilis and A. cylindricawere investigated. The fluorescence spectra of membrane fragments having four emissionbands at 645655, 685, 695 and 725 nm were basically similarto those reported for intact cells of blue-green algae, thoughthe emission from phycocyanin (645655 nm) was far strongerwith membrane fragments than with intact algal cells. Incubation of membrane fragments of A. variabilis in a dilutebuffer (102M, pH 7.5) caused an increase in the 645 nmfluorescence and slight decreases in the 685 and 695 nm fluorescences,but had no influence on the 725 nm fluorescence. The decreasein the 685 and 695 nm fluorescences of A. cylindrica was moremarked and had the same kinetics as the inactivation of photosystemII reaction measured by DPIP-photoreduction. When membrane fragments of A. cylindrica were incubated in thebuffer solution at room temperature or in the presence of MgCl2(103M) at 0°C; phycobilin aggregates, which emittedthe 655 and 685 nm fluorescence, were solubilized. This solubilizationwas not observed with membrane fragments of A. variabilis. (Received August 31, 1972; ) 相似文献
999.
Yoshinori Asakawa Reiko Matsuda Masao Toyota Shinske Hattori Guy Ourisson 《Phytochemistry》1981,20(9):2187-2194
Twenty-five Frullania species (liverworts) were chemically investigated. Fourteen species produce allergy-inducing sesquiterpene lactones. Eighteen species contain bibenzyls. The sesquiterpene lactones and bibenzyls are obtained as the major components and they are valuable chemosystematic markers of Frullania species. On the basis of their chemical constituents, Frullania species can be divided into five chemotypes: sesquiterpene lactone-bibenzyl type; sesquiterpene lactone type; bibenzyl type; monoterpene type and cyclocolorenone type. 相似文献
1000.
The liverwort Conocephalum supradecompositum belonging to the Marchantiales is a rich source of the germacranolides (+)-costunolide and (+)-dihydro 相似文献