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排序方式: 共有515条查询结果,搜索用时 812 毫秒
101.
Kosuke Minamihata Masamichi Tokunaga Noriho Kamiya Shiro Kiyoyama Haruhiko Sakuraba Toshihisa Ohshima Masahiro Goto 《Biotechnology letters》2009,31(7):1037-1041
Peptide tags containing tyrosines (Y-tag) were introduced at the C-terminus of a hyperthermophilic enzyme, alkaline phosphatase from Pyrococcus furiosus (PfuAP). Immobilization of the recombinant PfuAPs onto water-in-oil-in-water (W/O/W) type microcapsules was performed by
an in situ polymerization method. All the recombinant PfuAPs prepared in this study were quantitatively immobilized onto microcapsules.
The PfuAP-immobilized microcapsules showed no significant loss of enzymatic activity until the 5th round of assays. This result
implies that the recombinant PfuAPs were covalently immobilized onto microcapsules. Immobilized PfuAP tagged with a Y-tag
having the sequence GGYYY exhibited approximately a twofold higher catalytic activity compared with the wild-type PfuAP.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
102.
Tomomichi Chonan Takahiro Oi Daisuke Yamamoto Miyoko Yashiro Daisuke Wakasugi Hiroaki Tanaka Ayumi Ohoka-Sugita Fusayo Io Hiroko Koretsune Akira Hiratate 《Bioorganic & medicinal chemistry letters》2009,19(23):6645-6648
Acetyl-CoA carboxylases (ACCs), the rate limiting enzymes in de novo lipid synthesis, play important roles in modulating energy metabolism. The inhibition of ACC has demonstrated promising therapeutic potential for treating obesity and type 2 diabetes mellitus in transgenic mice and preclinical animal models. We describe herein the synthesis and structure–activity relationships of a series of disubstituted (4-piperidinyl)-piperazine derivatives as a new platform for ACC1/2 non-selective inhibitors. 相似文献
103.
Takuo Tsurugi Toshihisa Nagatomo Haruhiko Abe Yasushi Oginosawa Hiroko Takemasa Ritsuko Kohno Naomasa Makita Jonathan C. Makielski Yutaka Otsuji 《Life sciences》2009,84(11-12):380-387
AimsIn the type 3 long QT syndrome (LQT3), shortening of the QT interval by overdrive pacing is used to prevent life-threatening arrhythmias. However, it is unclear whether accelerated heart rate induced by β-adrenergic agents produces similar effects on the late sodium current (INa) to those by overdrive pacing therapy. We analyzed the β-adrenergic-like effects of protein kinase A and fluoride on INa in R1623Q mutant channels.Main methodscDNA encoding either wild-type (WT) or R1623Q mutant of hNav1.5 was stably transfected into HEK293 cells. INa was recorded using a whole-cell patch-clamp technique at 23 °C.Key findingsIn R1623Q channels, 2 mM pCPT-AMP and 120 mM fluoride significantly delayed macroscopic current decay and increased relative amplitude of the late INa in a time-dependent manner. Modulations of peak INa gating kinetics (activation, inactivation, recovery from inactivation) by fluoride were similar in WT and R1623Q channels. The effects of fluoride were almost completely abolished by concomitant dialysis with a protein kinase inhibitor. We also compared the effect of pacing with that of β-adrenergic stimulation by analyzing the frequency-dependence of the late INa. Fluoride augmented frequency-dependent reduction of the late INa, which was due to preferential delay of recovery of late INa. However, the increase in late INa by fluoride at steady-state was more potent than the frequency-dependent reduction of late INa.SignificanceDifferent basic mechanisms participate in the QT interval shortening by pacing and β-adrenergic stimulation in the LQT3. 相似文献
104.
Hiroyuki Ijima Hiroshi Mizumoto Kohji Nakazawa Toshihisa Kajiwara Taku Matsushita Kazumori Funatsu 《Biochemical Engineering Journal》2009,47(1-3):19-26
In our previous pre-clinical study with pig hepatic failure, an artificial liver with polyurethane foam (PUF)/primary porcine hepatocyte spheroids had superior curative effect. We examined the effect of hepatocyte growth factor (HGF), also known as scatter factor, on the quick formation of hepatocyte spheroids and albumin production. Spheroids were formed in the pores of PUF within 3 days regardless of addition of growth factors. In particular, spheroids were formed within 1 day in medium containing 100 ng/ml HGF and 50 ng/ml epidermal growth factor (EGF). 10,000 ng/ml HGF was effective for albumin production, but the activity dramatically decreased after 6 days in EGF-free medium. On the other hand, 100 ng/ml HGF was effective for albumin production in EGF-containing medium. Albumin production rate with ≥1000 ng/ml HGF was about 1.5 times higher than that with 100 ng/ml HGF. Furthermore, albumin production rate at 3 weeks was about 1.5 times higher than that at 2 days with 1000 ng/ml HGF. The maintenance of albumin production rate depended on the activity of the individual cell and not cell growth. In other words, we were able to show the effectiveness of HGF for functional hepatocyte organoid formation in PUF pores. 相似文献
105.
Rapid Pathway Evolution Facilitated by Horizontal Gene Transfers across Prokaryotic Lineages 总被引:1,自引:0,他引:1
The evolutionary history of biological pathways is of general interest, especially in this post-genomic era, because it may provide clues for understanding how complex systems encoded on genomes have been organized. To explain how pathways can evolve de novo, some noteworthy models have been proposed. However, direct reconstruction of pathway evolutionary history both on a genomic scale and at the depth of the tree of life has suffered from artificial effects in estimating the gene content of ancestral species. Recently, we developed an algorithm that effectively reconstructs gene-content evolution without these artificial effects, and we applied it to this problem. The carefully reconstructed history, which was based on the metabolic pathways of 160 prokaryotic species, confirmed that pathways have grown beyond the random acquisition of individual genes. Pathway acquisition took place quickly, probably eliminating the difficulty in holding genes during the course of the pathway evolution. This rapid evolution was due to massive horizontal gene transfers as gene groups, some of which were possibly operon transfers, which would convey existing pathways but not be able to generate novel pathways. To this end, we analyzed how these pathways originally appeared and found that the original acquisition of pathways occurred more contemporaneously than expected across different phylogenetic clades. As a possible model to explain this observation, we propose that novel pathway evolution may be facilitated by bidirectional horizontal gene transfers in prokaryotic communities. Such a model would complement existing pathway evolution models. 相似文献
106.
Takatomo Fujisawa Rei Narikawa Shinobu Okamoto Shigeki Ehira Hidehisa Yoshimura Iwane Suzuki Tatsuru Masuda Mari Mochimaru Shinichi Takaichi Koichiro Awai Mitsuo Sekine Hiroshi Horikawa Isao Yashiro Seiha Omata Hiromi Takarada Yoko Katano Hiroki Kosugi Satoshi Tanikawa Kazuko Ohmori Naoki Sato Masahiko Ikeuchi Nobuyuki Fujita Masayuki Ohmori 《DNA research》2010,17(2):85-103
107.
A novel alternative splicing isoform of human T-cell leukemia virus type 1 bZIP factor (HBZ-SI) targets distinct subnuclear localization 总被引:4,自引:0,他引:4 下载免费PDF全文
108.
In this paper, we describe a server/client literature management system specialized for the life science domain, the TogoDoc system (Togo, pronounced Toe-Go, is a romanization of a Japanese word for integration). The server and the client program cooperate closely over the Internet to provide life scientists with an effective literature recommendation service and efficient literature management. The content-based and personalized literature recommendation helps researchers to isolate interesting papers from the "tsunami" of literature, in which, on average, more than one biomedical paper is added to MEDLINE every minute. Because researchers these days need to cover updates of much wider topics to generate hypotheses using massive datasets obtained from public databases or omics experiments, the importance of having an effective literature recommendation service is rising. The automatic recommendation is based on the content of personal literature libraries of electronic PDF papers. The client program automatically analyzes these files, which are sometimes deeply buried in storage disks of researchers' personal computers. Just saving PDF papers to the designated folders makes the client program automatically analyze and retrieve metadata, rename file names, synchronize the data to the server, and receive the recommendation lists of newly published papers, thus accomplishing effortless literature management. In addition, the tag suggestion and associative search functions are provided for easy classification of and access to past papers (researchers who read many papers sometimes only vaguely remember or completely forget what they read in the past). The TogoDoc system is available for both Windows and Mac OS X and is free. The TogoDoc Client software is available at http://tdc.cb.k.u-tokyo.ac.jp/, and the TogoDoc server is available at https://docman.dbcls.jp/pubmed_recom. 相似文献
109.
Yuta Mutaguchi Taketo Ohmori Haruhiko Sakuraba Kazunari Yoneda Katsumi Doi Toshihisa Ohshima 《Analytical biochemistry》2011,(1):1
Methods with which to simply and rapidly assay l-aspartate (l-Asp) and d-aspartate (d-Asp) would be highly useful for physiological research and for nutritional and clinical analyses. Levels of l- and d-Asp in food and cell extracts are currently determined using high-performance liquid chromatography. However, this method is time-consuming and expensive. Here we describe a simple and specific method for using an l-aspartate dehydrogenase (l-AspDH) system to colorimetrically assay l-Asp and a system of three hyperthermophilic enzymes—aspartate racemase (AspR), l-AspDH, and l-aspartate oxidase (l-AO)—to assay d-Asp. In the former, the reaction rate of nicotinamide adenine dinucleotide (NAD+)-dependent l-AspDH was measured based on increases in the absorbance at 438 nm, reflecting formation of formazan from water-soluble tetrazolium-1 (WST-1), using 1-methoxy-5-methylphenazinum methyl sulfate (mPMS) as a redox mediator. In the latter, d-Asp was measured after first removing l-Asp in the sample solution with l-AO. The remaining d-Asp was then changed to l-Asp using racemase, and the newly formed l-Asp was assayed calorimetrically using NAD+-dependent aspartate dehydrogenase as described above. This method enables simple and rapid spectrophotometric determination of 1 to 100 μM l- and d-Asp in the assay systems. In addition, methods were applicable to the l- and d-Asp determinations in some living cells and foods. 相似文献
110.
Shin-ichi Sakasegawa Junji Hayashi Yoshiaki Ikura Shigeru Ueda Shigeyuki Imamura Toshihiko Kumazawa Atsuhisa Nishimura Toshihisa Ohshima Haruhiko Sakuraba 《Analytical biochemistry》2011,(1):61
Pyruvate phosphate dikinase (PPDK, EC 2.7.9.1) from the hyperthermophile Thermotoga maritima was biochemically characterized with the aim of establishing a colorimetric assay for inorganic pyrophosphate (PPi). When heterologously expressed in Escherichia coli, T. maritima PPDK (TmPPDK) was far more stable any other PPDK reported so far: it retained >90% of its activity after incubation for 1 h at 80 °C, and >80% of its activity after incubation for 20 min at pHs ranging from 6.5 to 10.5 (50 °C). In contrast to PPDKs from protozoa and plants, this TmPPDK showed very long-term stability at low temperature: full activity was retained even after storage for at least 2 years at 4 °C. TmPPDK was successfully applied to a novel colorimetric PPi assay, which employed (i) a PPi cycling reaction using TmPPDK and nicotinamide mononucleotide adenylyltransferase (EC 2.7.7.1) from Saccharomyces cerevisiae and (ii) a NAD cycling reaction to accumulate reduced nitroblue tetrazolium (diformazan). This enabled detection of 0.2 μM PPi, making this method applicable for preliminary measurement of PPi levels in PCR products in an automatic clinical analyzer. 相似文献