全文获取类型
收费全文 | 261篇 |
免费 | 13篇 |
专业分类
274篇 |
出版年
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 7篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 22篇 |
2012年 | 11篇 |
2011年 | 15篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 16篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 12篇 |
2000年 | 16篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 5篇 |
1992年 | 9篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有274条查询结果,搜索用时 15 毫秒
41.
C S Hun K Hasegawa T Kawabata M Kato T Shimokawa Y Kagawa 《Biochemical and biophysical research communications》1999,259(1):85-90
The effects of n-3 polyunsaturated fatty acids (n-3PUFA) on obesity and diabetes were examined using KK-Ay mice fed with perilla oil (P), soybean oil (S), or lard (L), and those containing 30% fish oil (PF, SF, or LF), containing eicosapentaenoic acid (EPA = 9.9%) and docosahexaenoic acid (DHA = 18.0%). Perilla oil contained the largest proportion of linolenic acid (LNA = 61.9%). Computerized tomography (CT) scans showed narrower areas of visceral fat in the abdominal cross sections of groups given fish oil (PF, SF, and LF) and lower leptin levels (p < 0.05-p < 0.001) compared with controls (P, S, and L), without significant changes in energy intake and body weight. The highest plasma n-3PUFA content (21.31 +/- 0.35%) was attained with PF. This group contained 2.6-fold more plasma DHA (p < 0.001), and expressed 2.7-fold more UCP2 mRNA in white adipose tissue (p < 0.01) than in the P group. The epididymal fat pad (p < 0.05) weighed less, and levels of blood glucose (p < 0.05) and total cholesterol (p < 0.01) were reduced in PF compared with P. 相似文献
42.
Essential histidines of prostaglandin endoperoxide synthase. His-309 is involved in heme binding 总被引:4,自引:0,他引:4
Prostaglandin endoperoxide (PGH) synthase has a single iron protoporphyrin IX which is required for both the cyclooxygenase and peroxidase activities of the enzyme. At room temperature, the heme iron is coordinated at the axial position by an imidazole, and about 20% of the heme iron is coordinated at the distal position by an imidazole. We have used site-directed mutagenesis to investigate which histidine residues are involved in PGH synthase catalysis and heme binding. Individual mutant cDNAs for ovine PGH synthases were prepared with amino acid substitutions at each of 13 conserved histidines. cos-1 cells were transfected with each of these cDNAs, and the cyclooxygenase and peroxidase activities of the resulting microsomal PGH synthases were measured. Mutant PGH synthases in which His-207, His-309, or His-388 was replaced with either glutamine or alanine lacked both activities. Gln-386 and Ala-386 PGH synthase mutants exhibited cyclooxygenase but not peroxidase activities. Other mutants exhibited both activities at varying levels. Because binding of heme renders native PGh synthase resistant to cleavage by trypsin, we examined the effects of heme on the relative sensitivities of native, Ala-204, Ala-207, Ala-309, Ala-386, and Ala-388 mutant PGH synthases to trypsin as a measure of the heme-protein interaction. The Ala-309 PGh synthase mutant was notably hypersensitive to tryptic cleavage, even in the presence of exogenous heme; in contrast, the native enzyme and the other alanine mutants exhibited similar, lower sensitivities toward trypsin and, except for the Ala-386 mutant, were partially protected from trypsin cleavage by heme. Preincubation of the native and each of the alanine mutant PGH synthases, including the Ala-309 mutant, with indomethacin protected the proteins from trypsin cleavage. Thus, all the mutant proteins retain sufficient three-dimensional structure to bind cyclooxygenase inhibitors. Our results suggest that His-309 is one of the heme ligands, probably the axial ligand, of PGH synthase. Two other histidines, His-207 and His-388, are essential for both PGH synthase activities suggesting that either His-207 or His-388 can serve as the distal heme ligand; however, the trypsin cleavage measurements imply that neither His-207 nor His-388 is required for heme binding. This is consistent with the fact that only 20% of the distal coordination position of the heme iron of PGH synthase is occupied by an imidazole side chain. 相似文献
43.
Masayoshi Yamaguchi Reiko Makino Noriaki Shimokawa 《Molecular and cellular biochemistry》1996,165(2):145-150
44.
45.
Kogure T Shirakawa S Shimokawa M Hosokawa Y 《Journal of physiological anthropology》2011,30(3):103-109
The purpose of this study was to formulate a "sleep/wake" scoring algorithm for processing activity measurements obtained using a newly developed nonwear actigraphy (NWA) device, and to test its validity. The NWA device has a highly sensitive pressure sensor and is placed under a mattress. It can continuously record the activity of a person lying on the mattress and identify an "in-bed/out-of-bed" state from the vibrations of the mattress. We formulated the sleep/wake scoring algorithm by using data obtained simultaneously by wrist actigraphy (Act) and the NWA device in 33 healthy participants. Agreement rate, sensitivity, and specificity with Act were 95.7%, 97.6%, and 75.8% (33 healthy people); the corresponding values were 85.9%, 89.1%, and 79.8% for 12 nursing home residents and 93.7%, 97.2%, and 60.8% for 60 nights for 6 healthy persons who slept 10 nights on their futons. Agreement rate, sensitivity, and specificity with polysomnography were in almost perfect agreement with Act (12 nights; 6 healthy persons who slept 2 nights). All our validation results indicate that the NWA device, placed under a mattress or a futon, can produce almost identical sleep/wake scores to Act. It is expected that the NWA device, a nonwear device for scoring sleep/wake and in-bed/out-of-bed, enables convenient long-term sleep-related evaluation in various fields, including hospital settings, home-care settings, and care facility settings such as nursing homes. 相似文献
46.
Preferential paternal origin of microdeletions caused by prezygotic chromosome or chromatid rearrangements in Sotos syndrome 总被引:3,自引:0,他引:3 下载免费PDF全文
Miyake N Kurotaki N Sugawara H Shimokawa O Harada N Kondoh T Tsukahara M Ishikiriyama S Sonoda T Miyoshi Y Sakazume S Fukushima Y Ohashi H Nagai T Kawame H Kurosawa K Touyama M Shiihara T Okamoto N Nishimoto J Yoshiura K Ohta T Kishino T Niikawa N Matsumoto N 《American journal of human genetics》2003,72(5):1331-1337
Sotos syndrome (SoS) is characterized by pre- and postnatal overgrowth with advanced bone age; a dysmorphic face with macrocephaly and pointed chin; large hands and feet; mental retardation; and possible susceptibility to tumors. It has been shown that the major cause of SoS is haploinsufficiency of the NSD1 gene at 5q35, because the majority of patients had either a common microdeletion including NSD1 or a truncated type of point mutation in NSD1. In the present study, we traced the parental origin of the microdeletions in 26 patients with SoS by the use of 16 microsatellite markers at or flanking the commonly deleted region. Deletions in 18 of the 20 informative cases occurred in the paternally derived chromosome 5, whereas those in the maternally derived chromosome were found in only two cases. Haplotyping analysis of the marker loci revealed that the paternal deletion in five of seven informative cases and the maternal deletion in one case arose through an intrachromosomal rearrangement, and two other cases of the paternal deletion involved an interchromosomal event, suggesting that the common microdeletion observed in SoS did not occur through a uniform mechanism but preferentially arose prezygotically. 相似文献
47.
48.
49.
A RecA-mediated exon profiling method 总被引:1,自引:0,他引:1
Hasegawa Y Fukuda S Shimokawa K Kondo S Maeda N Hayashizaki Y 《Nucleic acids research》2006,34(13):e97
We have developed a RecA-mediated simple, rapid and scalable method for identifying novel alternatively spliced full-length cDNA candidates. This method is based on the principle that RecA proteins allow to carry radioisotope-labeled probe DNAs to their homologous sequences, resulting in forming triplexes. The resulting complex is easily detected by mobility difference on electrophoresis. We applied this exon profiling method to four selected mouse genes as a feasibility study. To design probes for detection, the information on known exonic regions was extracted from public database, RefSeq. Concerning the potentially transcribed novel exonic regions, RNA mapping experiment using Affymetrix tiling array was performed. As a result, we were able to identify alternative splice variants of Thioredoxin domain containing 5, Interleukin1β, Interleukin 1 family 6 and glutamine-rich hypothetical protein. In addition, full-length sequencing demonstrated that our method could profile exon structures with >90% accuracy. This reliable method can allow us to screen novel splice variants from a huge number of cDNA clone set effectively. 相似文献
50.
Octopus vulgaris hemocyanin ( Ov-Hc) and one of its minimal functional units ( Ov-g) have been purified, and their spectroscopic features and monooxygenase (phenolase) activity have been examined in detail. The oxy forms of both Ov-Hc and Ov-g are stable in 0.5 M borate buffer (pH 9.0) even in the presence of a high concentration of urea at 25 degrees C; approximately 90 and approximately 75% of the (mu-eta (2):eta (2)-peroxo)dicopper(II) species of Ov-Hc and Ov-g, respectively, remained unchanged after argon (Ar) gas flushing of the sample solutions for 1 h. The catalytic activity of Ov-g in the oxygenation reaction (multiturnover reaction) of 4-methylphenol ( p-cresol) to 4-methyl-1,2-dihydroxybenzene (4-methylcatechol) was higher than that of Ov-Hc, and its catalytic activity was further accelerated by the addition of urea. Kinetic deuterium isotope effect analysis and Hammett analysis using a series of phenol derivatives under anaerobic conditions (single-turnover reaction) have indicated that the monooxygenation reaction of phenols to catechols by the peroxo species of oxyhemocyanin proceeds via electrophilic aromatic substitution mechanism as in the case of tyrosinase. The effect of urea on the redox functions of oxyhemocyanin is discussed on the basis of the spectroscopic analysis and reactivity studies. 相似文献