全文获取类型
收费全文 | 1951篇 |
免费 | 141篇 |
国内免费 | 1篇 |
出版年
2023年 | 7篇 |
2022年 | 6篇 |
2021年 | 18篇 |
2020年 | 12篇 |
2019年 | 19篇 |
2018年 | 26篇 |
2017年 | 38篇 |
2016年 | 54篇 |
2015年 | 53篇 |
2014年 | 80篇 |
2013年 | 116篇 |
2012年 | 119篇 |
2011年 | 124篇 |
2010年 | 89篇 |
2009年 | 83篇 |
2008年 | 109篇 |
2007年 | 122篇 |
2006年 | 129篇 |
2005年 | 126篇 |
2004年 | 139篇 |
2003年 | 140篇 |
2002年 | 148篇 |
2001年 | 17篇 |
2000年 | 19篇 |
1999年 | 24篇 |
1998年 | 32篇 |
1997年 | 25篇 |
1996年 | 18篇 |
1995年 | 21篇 |
1994年 | 23篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 12篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1975年 | 5篇 |
1972年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有2093条查询结果,搜索用时 156 毫秒
51.
52.
Akihiko Shimizu Hiroyuki Tsukagoshi Tsuyoshi Sekizuka Makoto Kuroda Aya Koizumi Masahiro Fujita Yoshiyuki Yamada Nobuhiro Saruki 《Microbiology and immunology》2020,64(9):630-634
Group B streptococcus (GBS) is a leading cause of neonatal infections. Most isolates are β-hemolytic, and their activity is considered to be pivotal for GBS pathogenicity. We report a case of a neonate with meningitis caused by nonhemolytic GBS. The patient developed meningitis 3 days after birth. Genotyping was performed and the characteristics of the strain (GCMC97051) identified by whole genome sequence using next generation sequencing. GCMC97051 possesses genetic alterations such as disruption of cylA by IS1381A insertion and a frameshift mutation in cylE, resulting in a lack of hemolysis. Thus, nonhemolytic GBS can retain the potential to cause invasive infections. 相似文献
53.
Hiroko Iijima Atsuko Watanabe Haruna Sukigara Tomokazu Shirai Akihiko Kondo Takashi Osanai 《Biotechnology and bioengineering》2020,117(6):1649-1660
Synechocystis sp. PCC 6803, a cyanobacterium widely used for basic research, is often cultivated in a synthetic medium, BG-11, in the presence of 4-(2-hydroxyethyl)-1-piperazine ethanesulfonic acid (HEPES) or 2-[[1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl]amino]ethanesulfonic acid buffer. Owing to the high cost of HEPES buffer (96.9% of the total cost of BG-11 medium), the biotechnological application of BG-11 is limited. In this study, we cultured Synechocystis sp. PCC 6803 cells in BG-11 medium without HEPES buffer and examined the effects on the primary metabolism. Synechocystis sp. PCC 6803 cells could grow in BG-11 medium without HEPES buffer after adjusting for nitrogen sources and light intensity; the production rate reached 0.54 g cell dry weight·L−1·day−1, exceeding that of commercial cyanobacteria and Synechocystis sp. PCC 6803 cells cultivated under other conditions. The exclusion of HEPES buffer markedly altered the metabolites in the central carbon metabolism; particularly, the levels of compatible solutes, such as sucrose, glucosylglycerol, and glutamate were increased. Although the accumulation of sucrose and glucosylglycerol under high salt conditions is antagonistic to each other, these metabolites accumulated simultaneously in cells grown in the cost-effective medium. Because these metabolites are used in industrial feedstocks, our results reveal the importance of medium composition for the production of metabolites using cyanobacteria. 相似文献
54.
Koichi Hirabayashi Masaaki Shiohara Kazuhiro Yamada Akane Sueki Yuichiro Ide Koichi Takeuchi Rokuro Hagimoto Tatsuya Kinoshita Akihiko Yabuhara S. Harvey Mudd Kenichi Koike 《Gene》2013
Background
There is not much information on established standard therapy for patients with severe methionine adenosyltransferase (MAT) I/III deficiency.Case presentation
We report a boy with MAT I/III deficiency, in whom plasma methionine and total homocysteine, and urinary homocystine were elevated. Molecular genetic studies showed him to have novel compound heterozygous mutations of the MAT1A gene: c.191T>A (p.M64K) and c.589delC (p.P197LfsX26). A low methionine milk diet was started at 31 days of age, and during continuing dietary methionine restriction plasma methionine levels have been maintained at less than 750 μmol/L. He is now 5 years old, and has had entirely normal physical growth and psychomotor development.Conclusions
Although some severely MAT I/III deficient patients have developed neurologic abnormalities, we report here the case of a boy who has remained neurologically and otherwise normal for 5 years during methionine restriction, suggesting that perhaps such management, started in early infancy, may help prevent neurological complications. 相似文献55.
Ryogo Hirata Coh-ichi Nihei Akihiko Nakano 《The Journal of biological chemistry》2013,288(52):37057-37070
p24 family proteins are evolutionarily conserved transmembrane proteins involved in the early secretory pathway. Saccharomyces cerevisiae has 8 known p24 proteins that are classified into four subfamilies (p24α, -β, -γ, and -δ). Emp24 and Erv25 are the sole members of p24β and -δ, respectively, and deletion of either destabilizes the remaining p24 proteins, resulting in p24 null phenotype (p24Δ). We studied genetic and physical interactions of p24α (Erp1, -5, and -6) and γ (Erp2, -3, and -4). Deletion of the major p24α (Erp1) partially inhibited p24 activity as reported previously. A second mutation in either Erp5 or Erp6 aggravated the erp1Δ phenotype, and the triple mutation gave a full p24Δ phenotype. Similar genetic interactions were observed among the major p24γ (Erp2) and the other two γ members. All the p24α/γ isoforms interacted with both p24β and -δ. Interaction between p24β and -δ was isoform-selective, and five major α/γ pairs were detected. These results suggest that the yeast p24 proteins form functionally redundant αβγδ complexes. We also identified Rrt6 as a novel p24δ isoform. Rrt6 shows only limited sequence identity (∼15%) to known p24 proteins but was found to have structural properties characteristic of p24. Rrt6 was induced when cells were grown on glycerol and form an additional αβγδ complex with Erp3, Erp5, and Emp24. This complex was mainly localized to the Golgi, whereas the p24 complex containing Erv25, instead of Rrt6 but otherwise with the same isoform composition, was found mostly in the ER. 相似文献
56.
Tsutomu Tanaka Sayoko Matsumoto Mari Yamada Ryosuke Yamada Fumio Matsuda Akihiko Kondo 《Applied microbiology and biotechnology》2013,97(10):4343-4352
Here, we demonstrate display of beta-glucosidase (BGL) on the surface of Schizosaccharomyces pombe cells using novel anchor proteins. A total of four candidate anchor proteins (SPBC21D10.06c, SPBC947.04, SPBC19C7.05, and SPBC359.04c) were selected from among almost all of S. pombe membrane proteins. The C-terminus of each anchor protein was genetically fused to the N-terminus of BGL, and the fusion protein was expressed using S. pombe as a host. The highest cell surface-associated BGL activity (107 U/105 cells was achieved with SPBC359.04c serving as the anchor, followed by SPBC947.04 (44 U/105 cells) and SPBC21D10.06c (38 U/105 cells). S. pombe displaying BGL with SPBC359.04c as an anchor showed the highest growth on 2 % cellobiose (10.7?×?107 cells/mL after 41 h of cultivation from an initial density of 0.1?×?107 cells/mL). Additionally, culturing BGL-displaying S. pombe in medium containing cellobiose as the sole carbon source did not affect protein expression, and ethanol fermentation from cellobiose was successfully demonstrated using BGL-displaying S. pombe. This is the first report describing a cell surface display system for the functionalization of S. pombe. 相似文献
57.
Chie Tomikawa Takayuki Ohira Yasushi Inoue Takuya Kawamura Akihiko Yamagishi Tsutomu Suzuki Hiroyuki Hori 《FEBS letters》2013
Thermoplasma acidophilum is a thermo-acidophilic archaeon. We purified tRNALeu (UAG) from T. acidophilum using a solid-phase DNA probe method and determined the RNA sequence after determining via nucleoside analysis and m7G-specific aniline cleavage because it has been reported that T. acidophilum tRNA contains m7G, which is generally not found in archaeal tRNAs. RNA sequencing and liquid chromatography–mass spectrometry revealed that the m7G modification exists at a novel position 49. Furthermore, we found several distinct modifications, which have not previously been found in archaeal tRNA, such as 4-thiouridine9, archaeosine13 and 5-carbamoylmethyuridine34. The related tRNA modification enzymes and their genes are discussed. 相似文献
58.
Takao Morita Akihiro NezuYosuke Tojyo Akihiko Tanimura 《Biochemical and biophysical research communications》2013
Adenoviruses have been used for gene transfer to salivary gland cells in vivo. Their use to study the function of salivary acinar cells was limited by a severe inflammatory response and by the destruction of fluid-secreting acinar cells. In the present study, low doses of adenovirus were administered to express Stim1-mKO1 by retrograde ductal injection to submandibular glands. The approach succeeded in increasing muscarinic stimulation-induced Ca2+ responses in acinar cells without inflammation or decreased salivary secretions. This increased Ca2+ response was notable upon weak muscarinic stimulation and was attributed to increased Ca2+ release from internal stores and increased Ca2+ entry. The basal Ca2+ level was higher in Stim1-mKO1-expressing cells than in mKO1-expressing and non-expressing cells. Exposure of permeabilized submandibular acinar cells, where Ca2+ concentration was fixed at 50 nM, to inositol 1,4,5-trisphosphate (IP3) produced similar effects on the release of Ca2+ from stores in Stim1-mKO1-expressing and non-expressing cells. The low toxicity and relative specificity to acinar cells of the mild gene transfer method described herein are particularly useful for studying the molecular functions of salivary acinar cells in vivo, and may be applied to increase salivary secretions in experimental animals and human in future. 相似文献
59.
Koji Ochiai Satoshi Takita Akihiko Kojima Tomohiko Eiraku Kazuhiko Iwase Tetsuya Kishi Akira Ohinata Yuichi Yageta Tokutaro Yasue David R. Adams Yasushi Kohno 《Bioorganic & medicinal chemistry letters》2013,23(1):375-381
(?)-6-(7-Methoxy-2-(trifluoromethyl)pyrazolo[1,5-a]pyridin-4-yl)-5-methyl-4,5-dihydropyridazin-3(2H)-one (KCA-1490) exhibits moderate dual PDE3/4-inhibitory activity and promises as a combined bronchodilatory/anti-inflammatory agent. N-alkylation of the pyridazinone ring markedly enhances potency against PDE4 but suppresses PDE3 inhibition. Addition of a 6-aryl-4,5-dihydropyridazin-3(2H)-one extension to the N-alkyl group facilitates both enhancement of PDE4-inhibitory activity and restoration of potent PDE3 inhibition. Both dihydropyridazinone rings, in the core and extension, can be replaced by achiral 4,4-dimethylpyrazolone subunits and the core pyrazolopyridine by isosteric bicyclic heteroaromatics. In combination, these modifications afford potent dual PDE3/4 inhibitors that suppress histamine-induced bronchoconstriction in vivo and exhibit promising anti-inflammatory activity via intratracheal administration. 相似文献
60.
Kentaro Takai Yasunao Inoue Yasuko Konishi Atsushi Suwa Yoshiharu Uruno Harumi Matsuda Tomokazu Nakako Mutsuko Sakai Hiroyuki Nishikawa Gakuji Hashimoto Takeshi Enomoto Atsushi Kitamura Yasuaki Uematsu Akihiko Kiyoshi Takaaki Sumiyoshi 《Bioorganic & medicinal chemistry letters》2013,23(16):4644-4647
We designed and synthesized N-substituted 8-azatetrahydroquinolone derivatives as selective M1 and M4 muscarinic acetylcholine receptors agonists. Optimization of selected derivatives led to the discovery of compound 7 as a highly potent M1 and M4 agonist with weak hERG inhibition. Oral administration of compound 7 improved psychosis-like behavior in rats. 相似文献