全文获取类型
收费全文 | 1910篇 |
免费 | 139篇 |
出版年
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 15篇 |
2018年 | 22篇 |
2017年 | 25篇 |
2016年 | 24篇 |
2015年 | 42篇 |
2014年 | 71篇 |
2013年 | 111篇 |
2012年 | 97篇 |
2011年 | 97篇 |
2010年 | 61篇 |
2009年 | 52篇 |
2008年 | 94篇 |
2007年 | 96篇 |
2006年 | 84篇 |
2005年 | 103篇 |
2004年 | 94篇 |
2003年 | 87篇 |
2002年 | 94篇 |
2001年 | 80篇 |
2000年 | 88篇 |
1999年 | 56篇 |
1998年 | 21篇 |
1997年 | 27篇 |
1996年 | 33篇 |
1995年 | 24篇 |
1994年 | 22篇 |
1993年 | 21篇 |
1992年 | 46篇 |
1991年 | 40篇 |
1990年 | 35篇 |
1989年 | 37篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 16篇 |
1984年 | 13篇 |
1983年 | 15篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 7篇 |
1979年 | 15篇 |
1978年 | 10篇 |
1975年 | 7篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1971年 | 6篇 |
1970年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有2049条查询结果,搜索用时 31 毫秒
101.
Opare Kennedy D Kojima A Hasuma T Yano Y Otani S Matsui-Yuasa I 《Chemico-biological interactions》2001,134(2):113-133
The effect of green tea extract (GTE) in Ehrlich ascites tumor cells (EATC) was studied with respect to changes in the intracellular kinase system involving mitogen-activated protein kinases (MAPKs) and cellular thiol. We have previously shown a reduction in viability of EATC and tyrosine phosphorylation of 42 and 45 kDa proteins by GTE and its polyphenolic component, Epigallocatechin (EGC) (D.O. Kennedy, S. Nishimura, T. Hasuma, Y. Yoshihisa, S. Otani, I. Matsui-Yuasa, Involvement of protein tyrosine phosphorylation in the effect of green tea polyphenols on Ehrlich ascites tumor cells in vitro, Chem. Biol. Interact. 110 (1998) 159-172). Furthermore, GTE and EGC significantly decreased both cellular non-protein and protein sulfhydryl levels in EATC, but replenishing thiol stores with N-acetylcysteine (NAC) caused a recovery in cell viability, and therefore SH groups were identified as a novel target of green tea cytotoxicity (D.O. Kennedy, M. Matsumoto, A. Kojima, I. Matsui-Yuasa, Cellular thiol status and cell death in the effect of green tea polyphenols in Ehrlich ascites tumor cells, Chem. Biol. Interact. 122 (1999) 59-71). In this study, we have observed the stimulation of three forms of MAPK, namely ERK1/2, JNK/SAPK and p38, by EGC, which were dose and time-dependent. These MAPK stimulations were found to be cellular thiol status-dependent events as NAC reversed these stimulations. Furthermore, inhibition of the p38 MAPK pathway using the p38 inhibitor SB203580 caused a marked dose-dependent reduction in the decrease in cell viability caused by EGC treatment. Inhibiting the Erk1/2 MAPK pathway using the MEK inhibitor PD098059 caused a slight change in the decrease in cell viability by EGC. These may suggest that the cytotoxicity associated with EGC was more associated with the other MAPKs than with ERK1/2. This may be the first study of its kind providing a novel evidence of a role for different forms of MAPKs in the antitumor effect of green tea polyphenols, especially EGC, in Ehrlich ascites tumor cells. 相似文献
102.
Takasaki Y Kogure T Takeuchi K Kaneda K Yano T Hirokawa K Hirose S Shirai T Hashimoto H 《Journal of immunology (Baltimore, Md. : 1950)》2001,166(7):4780-4787
Proliferating cell nuclear Ag (PCNA) occurs as a component of multiprotein complexes during cell proliferation. We found the complexes to react with murine anti-PCNA mAbs, but not with anti-PCNA Abs in lupus sera. The complexes were purified from rabbit thymus extract by affinity chromatography using anti-PCNA mAbs (TOB7, TO17, and TO30) and analyzed by ELISA, immunoprecipitation, immunoblotting, and HPLC gel filtration. That PCNA was complexed with other proteins was demonstrated by its copurification with a group of proteins excluded by an HPLC G3000 SW column. Although immunoblot analysis showed the mAbs to react exclusively with the 34-kDa PCNA polypeptide, they nonetheless immunoprecipitated the same group of proteins, confirming the interaction of the isolated PCNA with other proteins. Anti-PCNA sera, including AK, which reacts with biologically functional sites on PCNA, did not react with complexed PCNA, but did react with it once it was dissociated from the complexes. PCNA complexes in turn reacted with murine anti-DNA mAbs, as well as with Abs against p21, replication protein A, DNA helicase II, cyclin-dependent kinases 4 and 5, and topoisomerase I. These findings suggest that the PCNA complexes purified using anti-PCNA mAbs comprise the "protein machinery" for DNA replication and cell cycle regulation. They also suggest that anti-PCNA mAbs are useful tools with which to characterize the protein-protein interactions within PCNA complexes, as well as the autoimmune responses to proteins interacting with PCNA, which may shed light on the mechanisms of autoantibody production in lupus patients. 相似文献
103.
Hara M Wakasugi Y Ikoma Y Yano M Ogawa K Kuboi T 《Bioscience, biotechnology, and biochemistry》1999,63(2):433-437
A cDNA clone encoding a protein (CuCOR19), the sequence of which is similar to Poncirus COR19, of the dehydrin family was isolated from the epicarp of Citrus unshiu. The molecular mass of the predicted protein was 18,980 daltons. CuCOR19 was highly hydrophilic and contained three repeating elements including Lys-rich motifs. The gene expression in leaves increased by cold stress. 相似文献
104.
Angiopoietin-3, a novel member of the angiopoietin family 总被引:11,自引:0,他引:11
A cDNA clone encoding angiopoietin-3 protein (Ang3), a novel member of the angiopoietin family, was identified. Ang3 cDNA was cloned from a human aorta cDNA library. Ang3 is a 503 amino acid protein having 45.1% and 44.7% identity with human angiopoietin-1 and human angiopoietin-2, respectively. Ang3 mRNA is expressed in lung and cultured human umbilical vein endothelial cells (HUVECs). Ang3 mRNA expression in HUVECs was slightly decreased by vascular endothelial cell growth factor treatment, suggesting that the regulation of Ang3 mRNA expression is different from that of Ang2. 相似文献
105.
Okishima N Hagiwara Y Seito T Yano M Kido H 《Biochemical and biophysical research communications》1999,256(1):1-5
We established highly sensitive and specific sandwich-enzyme immunoassays (EIAs) for three newly discovered bioactive 31-amino acid endothelins [ETs(1-31)], which can detect as little as 0.16 pg/well of ET-1(1-31), 0.39 pg/well of ET-2(1-31), and 0.16 pg/well of ET-3(1-31). The EIAs showed no crossreactivity with 21-amino acid endothelins [ETs(1-21)] or big ETs at the usual assay concentrations below 1-5 ng/ml. In reversed-phase HPLC, immunoreactive ETs(1-31) in the granulocytes of normal human subjects eluted at the exact positions of authentic ETs(1-31), except for the presence of one additional unknown immunoreactive ET-1(1-31). The results also indicate that ETs(1-31) exist in the granulocytes at levels higher than or similar to those of ETs(1-21). This study is the first to establish EIAs for novel bioactive ETs(1-31). These assays can be utilized to assess the pathophysiological roles of ETs(1-31). 相似文献
106.
Protective immunity induced by vaccination with SAG1 gene-transfected cells against Toxoplasma gondii-infection in mice 总被引:11,自引:0,他引:11
Aosai F Mun HS Norose K Chen M Hata H Kobayashi M Kiuchi M Stauss HJ Yano A 《Microbiology and immunology》1999,43(1):87-91
To develop a vaccine by augmenting the protective cellular immunity against Toxoplasma gondii (T. gondii)-infection, T gondii SAG1 gene-transfectants were established by using RMA.S (H-2b), a murine transporter associated with the antigen processing (TAP) molecule-deficient lymphoma line, as a host antigen-presenting cell (APC). Immunization of C57BL/6 mice with the SAG1-transfected RMA.S induced CD8+ cytotoxic T lymphocytes (CTL) specific for not only SAG1-transfected RMA.S but also T gondii-infected RMA.S, and elicited protective responses to infection with a virulent T. gondii strain, RH. 相似文献
107.
Cytoplasmic dynein is a minus-end directed microtubule motor and plays important roles in the transport of various intracellular cargoes. Cytoplasmic dynein comprises two identical heavy chains and forms a dimer (double-headed dynein); the total molecular weight of the cytoplasmic dynein complex is about 1.5 million. The dynein motor domain is structurally very different from those of kinesin and myosin, and our understanding of the mechanisms of dynein energy transduction is limited mainly because of the difficulty in obtaining a sufficient quantity of purified and active cytoplasmic dynein. We purified cytoplasmic dynein, which was free from dynactin and other dynein-associated proteins. The purified cytoplasmic dynein was active in an in vitro motility assay. The controlled dialysis of the purified dynein against 4 M urea resulted in its complete dissociation into monomeric species (single-headed dynein). The separation of the dynein heads by the treatment was reversible. The MgATPase activities of the single-headed and reconstituted double-headed dynein were comparable to that of intact dynein. The double-headed dynein bundled microtubules in the absence of ATP; the single-headed dynein did not. The single-headed dynein produced in vitro microtubule-gliding motility at velocities very similar to those of double-headed dynein at various ATP concentrations. These results indicate that a single cytoplasmic dynein heavy chain is sufficient to produce robust microtubule motility. Application of the double- and single-headed dynein molecules in various assay systems will elucidate the mechanism of action of the cytoplasmic dynein. 相似文献
108.
109.
Ueda T Sato T Numa H Yano M 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,108(3):385-391
Wide variation in ultraviolet-B (UVB) resistance is observed among rice varieties. In a previous study, three quantitative trait loci (QTLs) controlling UVB resistance were detected by QTL analysis, using backcross inbred lines (BILs) derived from a cross between a japonica cultivar, Nipponbare, and an indica cultivar, Kasalath. Among them, qUVR-10, a QTL for UVB resistance on chromosome 10, showed the largest effect. Plants homozygous for the Nipponbare allele at qUVR-10 were resistant to UVB, unlike those homozygous for the Kasalath allele. To determine more precisely the chromosomal location of qUVR-10, we performed a linkage mapping of qUVR-10 as a single Mendelian factor using advanced backcross progeny. Advanced progeny testing of F4 families enabled us to determine the genotype classes of the qUVR-10 locus with high reliability. As a result, qUVR-10 was mapped between RFLP markers C60755S and C1757S, and co-segregated with C913A. In addition, a sequence showing high similarity to the Arabidopsis cyclobutane pyrimidine dimer (CPD) photolyase gene, which has been found to be involved in sensitivity to UV radiation in Arabidopsis and rice, was mapped in the candidate genomic region of qUVR-10. This result suggests that the CPD photolyase gene is a positional candidate for qUVR-10.Communicated by D.J. Mackill 相似文献
110.
Yano S 《Experimental & applied acarology》2004,32(4):243-248
Whether the spider mite Tetranychus urticae uses flying insects as vectors for phoretic dispersal was experimentally tested. Two bean plants were placed in a microcosm, and a mite population was introduced onto one of the plants. Either Phaenicia cuprina Wiedemann (Diptera: Calliphoridae) or Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) was then introduced into the microcosms as a hypothetical vector insect. T. urticae populations on the second bean plant were monitored to detect any evidence of phoretic dispersal. Instances of dispersal were detected at extremely low frequency, suggesting that phoretic dispersal of T. urticae mediated by winged insects is probably rare in the wild. 相似文献