全文获取类型
收费全文 | 901篇 |
免费 | 67篇 |
出版年
2021年 | 5篇 |
2020年 | 5篇 |
2018年 | 9篇 |
2017年 | 13篇 |
2016年 | 17篇 |
2015年 | 20篇 |
2014年 | 24篇 |
2013年 | 42篇 |
2012年 | 23篇 |
2011年 | 26篇 |
2010年 | 18篇 |
2009年 | 8篇 |
2008年 | 13篇 |
2007年 | 13篇 |
2006年 | 37篇 |
2005年 | 28篇 |
2004年 | 29篇 |
2003年 | 23篇 |
2002年 | 25篇 |
2001年 | 40篇 |
2000年 | 38篇 |
1999年 | 27篇 |
1997年 | 9篇 |
1996年 | 8篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 15篇 |
1992年 | 24篇 |
1991年 | 37篇 |
1990年 | 32篇 |
1989年 | 34篇 |
1988年 | 31篇 |
1987年 | 32篇 |
1986年 | 35篇 |
1985年 | 24篇 |
1984年 | 15篇 |
1983年 | 15篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 7篇 |
1979年 | 26篇 |
1978年 | 15篇 |
1977年 | 11篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1973年 | 10篇 |
1972年 | 6篇 |
1971年 | 5篇 |
1968年 | 6篇 |
排序方式: 共有968条查询结果,搜索用时 31 毫秒
41.
SFA-1, a novel cellular gene induced by human T-cell leukemia virus type 1, is a member of the transmembrane 4 superfamily. 总被引:5,自引:1,他引:4 下载免费PDF全文
A novel cellular gene termed SFA-1 was isolated by differential hybridization of a cDNA library, using probes obtained from an adult T-cell leukemia cell line in comparison with probes obtained from normal CD4+ T cells and the MOLT-4 cell line. The mRNA of the SFA-1 gene is approximately 1.6 kb in size and encodes a protein of 253 amino acids, containing four putative transmembrane domains, a number of cysteine residues, and one potential N-glycosylation site in a major hydrophilic region between the third and fourth transmembrane domains. Expression of the SFA-1 gene was either absent or present at a low level in lymphoid cells but was up-regulated after transformation by human T-cell leukemia virus type 1 and transactivated by Tax. SFA-1 was broadly expressed in many human cell types and conserved in different species. Computer-aided comparison showed that SFA-1 had significant sequence homology and common structural features with members of the transmembrane 4 superfamily. SFA-1 antigen was detected as a 29-kDa membrane protein by immunoblotting, using anti-SFA-1 monoclonal antibody. 相似文献
42.
Identification of the duplicated segments in rice chromosomes 1 and 5 by linkage analysis of cDNA markers of known functions 总被引:9,自引:0,他引:9
N. Kishimoto H. Higo K. Abe S. Arai A. Saito K. Higo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(6-7):722-726
We mapped two loci for ADP-ribosylation factor homologues (ARF1, ARF2) and two loci for cysteine proteinase inhibitors (oryzacystatin-I and -II: OCI, OCII) by linkage analysis of restriction fragment length polymorphism loci in rice (Oryza sativa L.) genomic DNAs using their cDNAs as probes.Oc-1 andArf-2 were found to be closely located to each other on chromosome 1, whileOc-2 andArf-1,both found on chromosome 5, were also located close to each other. The map distances are about 2 cM in both pairs. In each chromosome, theArf locus was located about 27 cM from that of the aldolase gene (Ald-2 in chromosome 1 andAld-1 in chromosome 5). These three genes are in the same order,Ald-Arf-Oc, but in opposite orientations relative to the distal ends of the linkage group. The presence of two sets of three linked genes on chromosomes 1 and 5 strongly suggests a structural similarity of the blocks of the two chromosomes, which probably reflects duplication of the segment. A recent investigation by other workers has shown that these rice blocks correspond to two regions in maize chromosomes 8 and 6, that have previously been shown to share many duplicated nucleotide sequences. It is therefore very likely that the duplication of the region occurred before the divergence of rice and maize during the evolution of the subfamilies of the grasses (Gramineae). In view of a recently discovered possible structural similarity between the small GTP-binding protein superfamily, which includesArf andras proteins, and the cystatin family, the close linkage ofOc andArf loci found in the present study suggests a possible cluster of genes related to the small GTP-binding proteins. 相似文献
43.
Summary A data smoothing algorithm by a one-pass method, employing spline function was applied to a laser turbidity meter for on-line measurement of cell mass and specific growth rate in the culture using recombinant E.coli The outputs from the laser turbidity meter containing noise and errors were successfully filtered by the method, leading to more reliable estimation of cell mass and specific growth rate in real time. 相似文献
44.
Nobuyuki Sugioka Hikaru Odani Toshio Ohta Hideki Kishimoto Tadaki Yasumura Kanji Takada 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1994,654(2)
Mycophenolate mofetil, a new immunosuppressant, is a morpholinoethyl ester of mycophenolic acid. A new selective, sensitive and simple high-performance liquid chromatographic method was developed for the determination of mycophenolic acid and mycophenolate mofetil in biological samples. The preparation of samples was based on liquid—liquid extraction. The compounds were separated on a CN column using acetonitrile—0.01 M phosphate buffer (1:4, v/v) as the mobile phase. UV detection was used at wavelengths 215 and 304 nm. The detection limit was 5 ng per injection volume. This method enabled pharmacokinetic and pharmacodynamic studies in humans and rats. 相似文献
45.
Acidiphilium aminolytica is proposed for a species of the genusAcidiphilium. Acidiphilium aminolytica can be phenotypically differentiated from all other species of the genusAcidiphilium. The seven strains of this species that have been studied are Gram-negative, aerobic, mesophilic, non-sporeforming, motile, and rod-shaped bacteria. They grow between pH 3.0 and 6.0, but not at pH 6.5. They yield positive results in tests for hippuric acid hydrolysis, catalase and urease production. Oxidase, esculin hydrolysis, and -galactosidase tests are negative. They can used-glucose,d-galactose, inositol, sorbitol,l-lysine,l-glutamate,l-arginine, -alanine,dl-4-aminobutyrate,dl-5-aminovalerate, sperimine, or diaminobutane as a sole carbon source, but cannot use elemental sulfur and ferrous iron as an energy source. The DNA base composition is 58.7–59.2 G+C mol%. The major isoprenoid quinone is ubiquinone with ten isoprene unit (Q-10). The major fatty acid is the C18:1 fatty acid. Two ornithine amide lipids, the C18:1 fatty acid esters of -N-3-hydroxystearylornithyltaurine and -N-3-hydroxystearylornithine, are detected as the polar aminolipid. DNA relatedness between this species and the other species ofAcidiphilium, the generaAcidomonas, andAcidobacterium was 29 to 2%. These results indicate, that this new species should be placed in the genusAcidiphilium. The type strain (strain 101) ofA. aminolytica is JCM 8796. 相似文献
46.
Hideyuki Yamamoto Futosi Arakane Tsunehiko Ono Kazuhiro Tashima Eiichi Okumura Keisuke Yamada Shin-ichi Hisanaga Kohji Fukunaga Takeo Kishimoto Eishichi Miyamoto 《Journal of neurochemistry》1995,65(2):802-809
Abstract: Excitatory amino acid (EAA) neurotransmitters may play a role in the pathophysiology of traumatic injury to the CNS. Although NMDA receptor antagonists have been reported to have therapeutic efficacy in animal models of brain injury, these compounds may have unacceptable toxicity for clinical use. One alternative approach is to inhibit the release of EAAs following traumatic injury. The present study examined the effects of administration of a novel sodium channel blocker and EAA release inhibitor, BW1003C87, or the NMDA receptor-associated ion channel blocker magnesium chloride on cerebral edema formation following experimental brain injury in the rat. Animals (n = 33) were subjected to fluid percussion brain injury of moderate severity (2.3 atm) over the left parietal cortex. Fifteen minutes after injury, the animals received a constant infusion of BW1003C87 (10 mg/kg, i.v.), magnesium chloride (300 µmol/kg, i.v.), or saline over 15 min (2.75 ml/kg/15 min). In all animals, regional tissue water content in brain was assessed at 48 h after injury, using the wet weight/dry weight technique. In saline-treated control animals, fluid percussion brain injury produced significant regional brain edema in injured left parietal cortex ( p < 0.001), the cortical area adjacent to the site of maximal injury ( p < 0.001), left hippocampus ( p < 0.001), and left thalamus ( p = 0.02) at 48 h after brain injury. Administration of BW1003C87 15 min postinjury significantly reduced focal brain edema in the cortical area adjacent to the site of maximal injury ( p < 0.02) and left hippocampus ( p < 0.01), whereas magnesium chloride attenuated edema in left hippocampus ( p = 0.02). These results suggest that excitatory neurotransmission may play an important role in the pathogenesis of posttraumatic brain edema and that pre- or post-synaptic blockade of glutamate receptor systems may attenuate part of the deleterious sequelae of traumatic brain injury. 相似文献
47.
R. Matsukawa Z. Dubinsky E. Kishimoto K. Masaki Y. Masuda T. Takeuchi M. Chihara Y. Yamamoto E. Niki I. Karube 《Journal of applied phycology》1997,9(1):29-35
The inhibition of lipid peroxidation and radical scavenging effects were studied to evaluate the antioxidant activity for
extracts of 17 species of seaweed. The antioxidant effect was evaluated by determination of lipoxygenase activity and by α,
α-diphenyl-β-picrylhydrazyl (DPPH) decolorization. Lipoxygenase activity was depressed in the presence of aqueous and ethanol
extracts of 4 algal species; Sargassum species had the highest antioxidant activity of all the species examined. The ethanol
extracts of one Sargassum species showed competitive inhibition with the substrate. The same species also showed radical scavenging
activity in the DPPH decolorization test. Comparison of these results shows no relationship between enzyme inhibition and
radical scavenging activity.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
48.
49.
Induction of proliferation and Ig production in human B leukemic cells by anti-immunoglobulins and T cell factors 总被引:20,自引:0,他引:20
K Yoshizaki T Nakagawa T Kaieda A Muraguchi Y Yamamura T Kishimoto 《Journal of immunology (Baltimore, Md. : 1950)》1982,128(3):1296-1301
The proliferation and differentiation of human leukemic B cells (B-CLL cells) with anti-Ig and T cell-derived helper factors are described. Stimulation of B-CLL cells with anti-Ig and T helper factors could induce proliferation as well as differentiation into IgM- and IgG-producing cells. Neither anti-Ig nor T helper factors alone could induce any proliferation and/or differentiation of B-CLL cells. Not only whole molecules of anti-Ig but also F(ab')2 fragments could induce proliferation and differentiation of B-CLL cells in the presence of T helper factors, but monovalent Fab' fragments were not effective. Induction of both IgM and IgG with the same idiotype was confirmed by immunofluorescent and SDS-PAGE analysis. By employing an IL 2-dependent cytotoxic T cell line and a TRF-responsive B cell line, T cell factors were separated into a fraction with IL2 activity but no TRF activity and a fraction with TRF activity but no IL 2 activity by chromatofocusing. Anti-Ig and IL 2 fraction could induce proliferation of B-CLL cells, but TRF fraction was not effective for the induction of proliferation in anti-IG-stimulated cells. For IgM and IgG production, anti-Ig and both IL 2 and TRF fractions were required. Depletion of IL 2 fraction in the first 2 days' culture inhibited Ig production, whereas the absence of TRF fraction in the first 2 days did not show any inhibitory effect on Ig production. 相似文献
50.
I Singh Y Kishimoto R R Vunnam N S Radin 《The Journal of biological chemistry》1979,254(10):3840-3844
Three synthetic compounds which affect sphingolipid metabolism in vitro were examined for their effects on the synthesis in a rat brain system of nonhydroxyceramide, hydroxyceramide, nonhydroxycerebroside, and hydroxycerebroside from [1-14C]ignoceric acid. These compounds are N-octanoyl-D-threo-p-nitrophenylaminopropanediol (Compound I), N-(2,3-epoxydecanoyl)-norephedrine (Compound II), and N-decyl-N'-glucosylthiourea (Compound III). In the presence of up to 0.5 mM Compound I, only the hydroxyceramide fromation increased, while the synthesis of the other three lipids decreased. Compound II strongly inhibited the formation of all four lipids at all concentrations tested (0.1 to 1 mM). Compound III increased the synthesis of both ceramides approximately 2-fold at 1 mM, but the conversion of lignoceric acid to both cerebrosides remained relatively unchanged. Several significant conclusions from these observations are discussed. 相似文献