全文获取类型
收费全文 | 470篇 |
免费 | 19篇 |
专业分类
489篇 |
出版年
2023年 | 1篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 11篇 |
2014年 | 11篇 |
2013年 | 73篇 |
2012年 | 22篇 |
2011年 | 31篇 |
2010年 | 11篇 |
2009年 | 10篇 |
2008年 | 30篇 |
2007年 | 35篇 |
2006年 | 37篇 |
2005年 | 31篇 |
2004年 | 23篇 |
2003年 | 42篇 |
2002年 | 17篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 2篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 11篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
排序方式: 共有489条查询结果,搜索用时 0 毫秒
461.
Teruhiko Yoshihara Katsuyoshi Yamaguchi Seiji Takamatsu Sadao Sakamura 《Bioscience, biotechnology, and biochemistry》2013,77(11):2593-2598
Two new phenolic amides, grossamide (7) and N-cis-feruloyl tyramine (2), have been isolated from the roots of bell pepper (Capsicum annuum var. grossum) together with p-aminobenzaldehyde (1), N-trans-feruloyl tyramine (3), N-trans-p-coumaroyl tyramine (4), N-trans-feruloyl octopamine (5), and N-trans-p-coumaroyl octopamine (6). 相似文献
462.
Akira Yanai Teruhiko Beppu Kei Arima 《Bioscience, biotechnology, and biochemistry》2013,77(1):149-151
Lipogenesis in the fatty liver of rat, which was induced by feeding an amino acid unbalanced diet containing 8% casein supplemented with 0.3% dl-methionine, has been studied by measuring the incorporation of glycerol-1-14C, palmitate-1-14C, citrate-1,5-14C, pyruvate-1-14C and pyruvate-2-14C into various lipid fractions and 14CO2 during in vitro incubation of liver slices.The total radioactivity of liver lipid per 100 g of the body and the incorporation of each substrate into triglyceride in the lipid were significantly higher in the imbalance group than the control group. Conversion of each substrate to 14CO2 was not imparied in the imbalance group.It is evident from these results that the induction of this type of fatty liver is due mainly to the triglyceride synthesis by both the fatty acid synthesis and the transesterification of fatty acid.These results are considered to support the previous assumption in which acetate-1-14C was used as a precursor. 相似文献
463.
Porcine pancreatic lipase (PPL)-catalyzed enantioselective hydrolysis of N-benzyloxycarbonyl-dl-amino acid esters (Z-dl-AA-ORs) was studied for the optical resolution of a variety of non-protein amino acids. The ester moiety (R) of the substrate affected the rate of hydrolysis significantly. The glyceryl (Gl) and carbamoylmethyl (Cam) esters were found to be highly reactive substrates. The hydrolysis of the Gl esters (Z-dl-AA-OGls) of both aliphatic and aromatic amino acids was examined in acetonitrile containing 70% (v/v) of 0.02 M phosphate buffer (pH 7.0) at 30°C. With all amino acids tested, the corresponding l-enantiomers were hydrolyzed preferentially. PPL favored aromatic amino acids, such as phenylalanine and p-chlorophenylalanine, leading to completion of the hydrolysis within 20 min with excellent enantioselectivities (E>100). The PPL-catalyzed hydrolysis of the corresponding Cam esters (Z-dl-AA-OCams) was also examined under the same reaction conditions. Although the hydrolysis of the Cam esters was rapid, the l-enantioselectivities were rather poor with aromatic amino acids, such as 2-phenylglycine and homophenylalanine. 相似文献
464.
Using Environmental DNA to Estimate the Distribution of an Invasive Fish Species in Ponds 总被引:2,自引:0,他引:2
Knowledge of the presence of an invasive species is critical to monitoring the sustainability of communities and ecosystems. Environmental DNA (eDNA), DNA fragments that are likely to be bound to organic matters in the water or in shed cells, has been used to monitor the presence of aquatic animals. Using an eDNA-based method, we estimated the presence of the invasive bluegill sunfish, Lepomis macrochirus, in 70 ponds located in seven locales on the Japanese mainland and on surrounding islands. We quantified the concentration of DNA copies in a 1 L water sample using quantitative real-time polymerase chain reaction (qPCR) with a primer/probe set. In addition, we visually observed the bluegill presence in the ponds from the shoreline. We detected bluegill eDNA in all the ponds where bluegills were observed visually and some where bluegills were not observed. Bluegills were also less prevalent on the islands than the mainland, likely owing to limited dispersal and introduction by humans. Our eDNA method simply and rapidly detects the presence of this invasive fish species with less disturbance to the environment during field surveys than traditional methods. 相似文献
465.
Iwano M Shiba H Matoba K Miwa T Funato M Entani T Nakayama P Shimosato H Takaoka A Isogai A Takayama S 《Plant physiology》2007,144(1):72-81
The self-incompatibility system of the plant species Brassica is controlled by the S-locus, which contains S-RECEPTOR KINASE (SRK) and S-LOCUS PROTEIN11 (SP11). SP11 binding to SRK induces SRK autophosphorylation and initiates a signaling cascade leading to the rejection of self pollen. However, the mechanism controlling hydration and germination arrest during self-pollination is unclear. In this study, we examined the role of actin, a key cytoskeletal component regulating the transport system for hydration and germination in the papilla cell during pollination. Using rhodamine-phalloidin staining, we showed that cross-pollination induced actin polymerization, whereas self-pollination induced actin reorganization and likely depolymerization. By monitoring transiently expressed green fluorescent protein fused to the actin-binding domain of mouse talin, we observed the concentration of actin bundles at the cross-pollen attachment site and actin reorganization and likely depolymerization at the self-pollen attachment site; the results correspond to those obtained by rhodamine-phalloidin staining. We further showed that the coat of self pollen is sufficient to mediate this response. The actin-depolymerizing drug cytochalasin D significantly inhibited pollen hydration and germination during cross-pollination, further emphasizing a role for actin in these processes. Additionally, three-dimensional electron microscopic tomography revealed the close association of the actin cytoskeleton with an apical vacuole network. Self-pollination disrupted the vacuole network, whereas cross-pollination led to vacuolar rearrangements toward the site of pollen attachment. Taken together, our data suggest that self- and cross-pollination differentially affect the dynamics of the actin cytoskeleton, leading to changes in vacuolar structure associated with hydration and germination. 相似文献
466.
Identification of Indole Derivatives as Self-Growth Inhibitors of Symbiobacterium thermophilum, a Unique Bacterium Whose Growth Depends on Coculture with a Bacillus sp. 下载免费PDF全文
Tomo-o Watsuji Shinya Yamada Tomoya Yamabe Yuka Watanabe Taira Kato Takao Saito Kenji Ueda Teruhiko Beppu 《Applied microbiology》2007,73(19):6159-6165
Symbiobacterium thermophilum is a syntrophic bacterium whose growth depends on coculture with a Bacillus sp. Recently, we discovered that CO2 generated by Bacillus is the major inducer for the growth of S. thermophilum; however, the evidence suggested that an additional element is required for its full growth. Here, we studied the self-growth-inhibitory substances produced by S. thermophilum. We succeeded in purifying two substances from an ether extract of the culture supernatant of S. thermophilum by multiple steps of reverse-phase chromatography. Electron ionization mass spectrometry and nuclear magnetic resonance analyses of the purified preparation identified the substances as 2,2-bis(3′-indolyl)indoxyl (BII) and 1,1-bis(3′-indolyl)ethane (BIE). The pure growth of S. thermophilum was inhibited by authentic BII and BIE with MICs of 12 and 7 μg/ml, respectively; however, its growth in coculture with Bacillus was not inhibited by BII at the saturation concentration and was inhibited by BIE with an MIC of 14 μg/ml. Both BII and BIE inhibited the growth of other microorganisms. Unexpectedly, the accumulation levels of both BII and BIE in the pure culture of S. thermophilum were far lower than the MICs (<0.1 μg/ml) while a marked amount of BIE (6 to 7 μg/ml) equivalent to the MIC had accumulated in the coculture. An exogenous supply of surfactin alleviated the sensitivities of several BIE-sensitive bacteria against BIE. The results suggest that Bacillus benefits S. thermophilum by detoxifying BII and BIE in the coculture. A similar mechanism may underlie mutualistic relationships between different microorganisms. 相似文献
467.
468.
Human artificial chromosomes (HACs) are gene-delivery vectors suitable for introducing large DNA fragments into mammalian cells. Although a HAC theoretically incorporates multiple gene expression cassettes of unlimited DNA size, its application has been limited because the conventional gene-loading system accepts only one gene-loading vector (GLV) into a HAC. We report a novel method for the simultaneous or sequential integration of multiple GLVs into a HAC vector (designated as the SIM system) via combined usage of Cre, FLP, Bxb1, and φC31 recombinase/integrase. As a proof of principle, we first attempted simultaneous integration of three GLVs encoding EGFP, Venus, and TdTomato into a gene-loading site of a HAC in CHO cells. These cells successfully expressed all three fluorescent proteins. Furthermore, microcell-mediated transfer of HACs enabled the expression of those fluorescent proteins in recipient cells. We next demonstrated that GLVs could be introduced into a HAC one-by-one via reciprocal usage of recombinase/integrase. Lastly, we introduced a fourth GLV into a HAC after simultaneous integration of three GLVs by FLP-mediated DNA recombination. The SIM system expands the applicability of HAC vectors and is useful for various biomedical studies, including cell reprogramming. 相似文献
469.
Takuya Miyazaki Yong-Soo Kim Jeongheon Yoon Hongsheng Wang Teruhiko Suzuki Herbert C. Morse III 《The Journal of biological chemistry》2014,289(47):32548-32558
The main function of the 3′–5′ DNA exonuclease TREX1 is to digest cytosolic single-stranded DNA to prevent activation of cell-intrinsic responses to immunostimulatory DNA. TREX1 translocates to the nucleus following DNA damage with its nuclear activities being less well defined. Although mutations in human TREX1 have been linked to autoimmune/inflammatory diseases, the mechanisms contributing to the pathogenesis of these diseases remain incompletely understood. Here, using mass spectrometry and co-immunoprecipitation assays and in vivo overexpression models, we show that TREX1 interacts with poly(ADP-ribose) polymerase-1 (PARP1), a nuclear enzyme involved in the DNA damage response. Two zinc finger domains at the amino terminus of PARP1 were required for the interaction with TREX1 that occurs after nuclear translocation of TREX1 in response to DNA damage. Functional studies suggested that TREX1 may contribute to stabilization of PARP1 levels in the DNA damage response and its activity. These results provide new insights into the mechanisms of single-stranded DNA repair following DNA damage and alterations induced by gene mutations. 相似文献
470.
Subchronic treatment with MAP (4.6 mg/kg, i.p., once daily for 11 days) significantly decreased the Kd, but not Bmax, values of [3H]1,3-dipropyl-8-cyclopentylxanthine ([3H]DPCPX) binding to adenosine A1 receptors in the prefrontal cortex and hippocampus, but not striatum, of rat brain. However, subchronic treatment with PCP (10 mg/kg, i.p., once daily for 11 days) did not alter the Kd and Bmax values of [3H]DPCPX binding to adenosine A1 receptors in these three regions. Subchronic treatment with MAP or PCP did not alter the Bmax and Kd values of [3H]2-p-(2-carboxyehyl)phenethylamino-5-N-ethylcarboxyamidoadenosine ([3H]CGS21680) binding to adenosine A2A receptors in the striatum. Furthermore, subchronic treatment with MAP or PCP significantly decreased the specific binding of [3H]CGS21680 to adenosine A2A receptors in the hippocampus, but not in the prefrontal cortex. Thus, these results suggest that MAP and PCP may produce differential effects on the adenosine A2A receptors, but not adenosine A1 receptors in rat brain. 相似文献