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排序方式: 共有409条查询结果,搜索用时 15 毫秒
1.
H Masuno T Tsujita H Nakanishi A Yoshida R Fukunishi H Okuda 《Journal of lipid research》1984,25(5):419-427
The triglyceride lipase (TGL) activity of liver homogenates of mice with Sarcoma 180 was measured. The liver homogenate of normal or tumor-bearing mice was treated with 0.25% Triton X-100 and centrifuged at 100,000 g for 60 min, and the supernatant was applied to a heparin-Sepharose column. In normal mice, most of the TGL activities in the supernatant was eluted with 0.75 M NaCl from the column. In mice with Sarcoma 180, the TGL gave two peaks on heparin-Sepharose column chromatography, which were eluted with 0.75 M and 1.5 M NaCl, respectively. The activity in the first peak (0.75 M NaCl eluate) decreased; that in the second peak (1.5 M NaCl eluate) increased, and the ratio of the second peak to the first peak increased during tumor development. The livers of normal mice and mice on day 10 after tumor inoculation were perfused with heparin. The highest rate of the TGL release occurred within 1 min of heparin perfusion, and the bulk of heparin-releasable activity appeared within 2 min of perfusion in both normal and tumor-bearing mice. The TGL activity in liver perfusate of tumor-bearing mice, as well as that of liver homogenate, was resolved on a heparin-Sepharose column into two peaks, which were eluted with 0.75 M and 1.5 M NaCl, and most of the activity was eluted with 1.5 M NaCl. The nature of the TGL activity eluted from a heparin-Sepharose column was investigated. In both liver homogenates and liver perfusates, the first peak did not require serum for maximal activity and was relatively resistant to a high concentration of NaCl or protamine sulfate.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
2.
The "esterase" activity of hormone-sensitive lipase (HSL) was studied using water-soluble p-nitrophenyl butyrate (PNPB) as a substrate. Bovine adipose tissue HSL was purified to near homogeneity by precipitation at pH 5.0, followed by chromatography on DEAE-cellulose, phenyl-Sepharose, and high performance ion-exchange columns on Mono Q and Mono S. The purified preparation hydrolyzed emulsified triolein and cholesteryl oleate (CO), and water-soluble PNPB. In the two last steps of purification, the elution profile of the CO-hydrolyzing activity coincided with that of PNPB-hydrolyzing activity. The HSL was adsorbed to heparin-Sepharose and the CO- and PNPB-hydrolyzing activities were eluted together in the same peak. Diisopropylfluorophosphate (DFP) strongly inhibited the HSL activities and the inhibition profiles of the triolein-; CO-, and PNPB-hydrolyzing activities were essentially identical. Only one polypeptide of Mr 84,000 in partial purified HSL fraction was labeled by affinity labeling with [3H]DFP. On digestion of the enzyme with trypsin, the triolein- and CO-hydrolyzing activities were lost more rapidly than the PNPB-hydrolyzing activity. Phosphorylation increased the triolein-hydrolyzing activity to 40% more than that of the control, but did not affect the CO- and PNPB-hydrolyzing activities. 相似文献
3.
Molecular cloning of cDNA for the import precursor of human subunit B of H(+)-ATP synthase in mitochondria. 总被引:1,自引:0,他引:1
T Higuti C Tsurumi F Osaka Y Kawamura H Tsujita Y Yoshihara I Tani K Tanaka A Ichihara 《Biochemical and biophysical research communications》1991,178(3):1014-1020
The nucleotide sequence of the import precursor of subunit b of human H(+)-ATP synthase has been determined from a recombinant cDNA clone isolated by screening a human kidney cDNA library with a cDNA for rat subunit b as a probe. The sequence was composed of 1,134 nucleotides including a coding region for the import precursor of subunit b and noncoding regions on the 5'- and 3'-sides. The import precursor of subunit b and its mature polypeptide deduced from the open reading frame were found to consist of 256 and 214 amino acid residues with molecular weights of 28,893 and 24,610, respectively. The presequence of 42 amino acids could be the import signal peptide for directing the protein into the mitochondrial matrix. 相似文献
4.
Daphnia pulex and D. mitsukuri are morphologically similar and distributed in small lowland Japanese lakes. Daphnia pulex in Japan reproduces by obligate parthenogenesis and is composed of four different lineages (JPN1–JPN4) with North American origins. Although this species is found throughout Japan, JPN1 has the largest distribution range, followed by JPN2. Daphnia mitsukuri is a putatively endemic species that is now rarely found in Japan. Since Daphnia share the same algal food, the difference in distribution ranges among the four asexual D. pulex lineages and D. mitsukuri may be caused by exploitative competition for algal food. To examine this possibility, we measured the threshold food concentration (TFC) at zero-net growth rate and the food concentration required for 50% of the individuals to survive (FC50). In addition, we examined the effects of temperature on the somatic growth rate (SGR) and the mortality rates of four asexual D. pulex lineages and D. mitsukuri. The experiments showed that TFC was lowest in D. pulex JPN1 and highest in D. mitsukuri, supporting the idea that the largest distribution range of JPN1 is due to its superiority in inter-lineage competition, and that the distribution area of D. mitsukuri is reduced through exploitative competition with D. pulex. However, although JPN2 was found in relatively large areas, it had higher TFC than JPN3 and JPN4, which appear in very limited areas. These results clearly showed that the difference in distribution ranges among D. pulex lineages are not necessarily determined by their competitive superiority alone. 相似文献
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6.
Erik J. Ragsdale Natsumi Kanzaki Waltraud Röseler Matthias Herrmann Ralf J. Sommer 《Zoological Journal of the Linnean Society》2013,168(4):671-698
Developmental plasticity is often correlated with diversity and has been proposed as a facilitator of phenotypic novelty. Yet how a dimorphism arises or how additional morphs are added is not understood, and few systems provide experimental insight into the evolution of polyphenisms. Because plasticity correlates with structural diversity in Pristionchus nematodes, studies in this group can test the role of plasticity in facilitating novelty. Here, we describe three new species, Pristionchus fukushimae sp. nov. , Pristionchus hoplostomus sp. nov. , and the hermaphroditic Pristionchus triformis sp. nov. , which are characterized by a novel polymorphism in their mouthparts. In addition to showing the canonical mouth dimorphism of diplogastrid nematodes, comprising a stenostomatous (‘narrow‐mouthed’) and a eurystomatous (‘wide‐mouthed’) form, the new species exhibit forms with six, 12, or intermediate numbers of cheilostomatal plates. Correlated with this polymorphism is another trait that varies among species: whereas divisions between plates are complete in P. triformis sp. nov. , which is biased towards a novel ‘megastomatous’ form comprising 12 complete plates, the homologous divisions in the other new species are partial and of variable length. In a reconstruction of character evolution, a phylogeny inferred from 26 ribosomal protein genes and a partial small subunit rRNA gene supported the megastomatous form of P. triformis sp. nov. as the derived end of a series of split‐plate forms. Although split‐plate forms were normally only observed in eurystomatous nematodes, a single 12‐plated stenostomatous individual of P. hoplostomus sp. nov. was also observed, suggesting independence of the two types of mouth plasticity. By introducing these new species to the Pristionchus model system, this study provides further insight into the evolution of polymorphisms and their evolutionary intermediates. © 2013 The Linnean Society of London 相似文献
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9.
Tomoyuki Makino Maya Yamashita Natsumi Takeuchi Toshihide Kabuki Makoto Hattori 《Bioscience, biotechnology, and biochemistry》2013,77(12):2298-2306
ABSTRACTLactic acid bacteria are known to have various health-promoting effects and are highly expected to find applications in anti-allergic food materials. In this study, we focused on Lactobacillus helveticus SBT2171 (LH2171), which reportedly modifies some unique immune responses and ameliorated symptoms of patients allergic to mites and house dust in the previous studies. We examined the effect of LH2171 on cytokine production by antigen-stimulated murine naïve splenocytes in vitro and demonstrated that it inhibited IL-4 and IL-13 production while enhancing IFN-γ and IL-10 production. Then, we examined the anti-allergic effect of LH2171 in vivo using a murine model of pollen allergy and found that LH2171 reduced the sneezing frequency when orally administered to mice. We successfully confirmed the immune modulatory activity of LH2171 and its anti-allergic activity against inhaled antigens. These evidences would contribute to identifying the anti-allergic mechanism of LH2171.Abbreviations: ALDH: aldehyde dehydrogenase; EGCG: epigallocatechin gallate; LAB: lactic acid bacteria; LH2171: Lactobacillus helveticus SBT2171; NALT: nasal-associated lymphoid tissue; OVA: ovalbumin 相似文献
10.
Yuki Hatanaka Natsumi Shimizu Satoshi Nishikawa Mikiko Tokoro Seung-Wook Shin Takuji Nishihara Tomoko Amano Masayuki Anzai Hiromi Kato Tasuku Mitani Yoshihiko Hosoi Satoshi Kishigami Kazuya Matsumoto 《PloS one》2013,8(4)
After fertilization, the sperm and oocyte genomes undergo extensive epigenetic reprogramming to form a totipotent zygote. The dynamic epigenetic changes during early embryo development primarily involve DNA methylation and demethylation. We have previously identified Gse (gonad-specific expression gene) to be expressed specifically in germ cells and early embryos. Its encoded protein GSE is predominantly localized in the nuclei of cells from the zygote to blastocyst stages, suggesting possible roles in the epigenetic changes occurring during early embryo development. Here, we report the involvement of GSE in epigenetic reprogramming of the paternal genome during mouse zygote development. Preferential binding of GSE to the paternal chromatin was observed from pronuclear stage 2 (PN2) onward. A knockdown of GSE by antisense RNA in oocytes produced no apparent effect on the first and second cell cycles in preimplantation embryos, but caused a significant reduction in the loss of 5-methylcytosine (5mC) and the accumulation of 5-hydroxymethylcytosine (5hmC) in the paternal pronucleus. Furthermore, DNA methylation levels in CpG sites of LINE1 transposable elements, Lemd1, Nanog and the upstream regulatory region of the Oct4 (also known as Pou5f1) gene were clearly increased in GSE-knockdown zygotes at mid-pronuclear stages (PN3-4), but the imprinted H19-differential methylated region was not affected. Importantly, DNA immunoprecipitation of 5mC and 5hmC also indicates that knockdown of GSE in zygotes resulted in a significant reduction of the conversion of 5mC to 5hmC on LINE1. Therefore, our results suggest an important role of maternal GSE for mediating active DNA demethylation in the zygote. 相似文献