全文获取类型
收费全文 | 366篇 |
免费 | 22篇 |
专业分类
388篇 |
出版年
2021年 | 2篇 |
2019年 | 4篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 21篇 |
2014年 | 14篇 |
2013年 | 30篇 |
2012年 | 23篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 5篇 |
2007年 | 24篇 |
2006年 | 29篇 |
2005年 | 17篇 |
2004年 | 19篇 |
2003年 | 12篇 |
2002年 | 29篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有388条查询结果,搜索用时 0 毫秒
101.
Katsura Maeda-Sano Mari Gotoh Toshiro Morohoshi Takao Someya Hiromu Murofushi Kimiko Murakami-Murofushi 《Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids》2014,1841(9):1256-1263
Cyclic phosphatidic acid (cPA) is a naturally occurring phospholipid mediator and an analog of the growth factor-like phospholipid lysophosphatidic acid (LPA). cPA has a unique cyclic phosphate ring at the sn-2 and sn-3 positions of its glycerol backbone. We showed before that a metabolically stabilized cPA derivative, 2-carba-cPA, relieved osteoarthritis pathogenesis in vivo and induced hyaluronic acid synthesis in human osteoarthritis synoviocytes in vitro. This study focused on hyaluronic acid synthesis in human fibroblasts, which retain moisture and maintain health in the dermis. We investigated the effects of cPA and LPA on hyaluronic acid synthesis in human fibroblasts (NB1RGB cells). Using particle exclusion and enzyme-linked immunosorbent assays, we found that both cPA and LPA dose-dependently induced hyaluronic acid synthesis. We revealed that the expression of hyaluronan synthase 2 messenger RNA and protein is up-regulated by cPA and LPA treatment time dependently. We then characterized the signaling pathways up-regulating hyaluronic acid synthesis mediated by cPA and LPA in NB1RGB cells. Pharmacological inhibition and reporter gene assays revealed that the activation of the LPA receptor LPAR1, Gi/o protein, phosphatidylinositol-3 kinase (PI3K), extracellular-signal-regulated kinase (ERK), and cyclic adenosine monophosphate response element-binding protein (CREB) but not nuclear factor κB induced hyaluronic acid synthesis by the treatment with cPA and LPA in NB1RGB cells. These results demonstrate for the first time that cPA and LPA induce hyaluronic acid synthesis in human skin fibroblasts mainly through the activation of LPAR1-Gi/o followed by the PI3K, ERK, and CREB signaling pathway. 相似文献
102.
Toshikazu Takino Hiroyuki Yasui Akira Yoshitake Yoshio Hamajima ·Rokuji Matsushita Jitsuya Takada Hiromu Sakurai 《Journal of biological inorganic chemistry》2001,6(2):133-142
A new vanadyl complex, bis(5-iodopicolinato)oxovanadium(IV), VO(IPA)2, with a VO(N2O2) coordination mode, was prepared by mixing 5-iodopicolinic acid and VOSO4 at pH 5, with the structure characterized by electronic absorption, IR, and EPR spectra. Introduction of the halogen atom on to the ligand enhanced the in vitro insulinomimetic activity (IC50 = 0.45 mM) compared with that of bis(picolinato)oxovanadium(IV) (IC50 = 0.59 mM). The hyperglycemia of streptozotocin-induced insulin-dependent diabetic rats was normalized when VO(IPA)2 was given by daily intraperitoneal injection. The normoglycemic effect continued for more than 14 days after the end of treatment. To understand the insulinomimetic action of VO(IPA)2, the organ distribution of vanadium and the blood disposition of vanadyl species were investigated. In diabetic rats treated with VO(IPA)2, vanadium was distributed in almost all tissues examined, especially in bone, indicating that the action of vanadium is not peripheral. Vanadyl concentrations in the blood of normal rats given VO(IPA)2 remain significantly higher and longer than those given other complexes because of its slower clearance rate. VO(IPA)2 binds with the membrane of erythrocytes, probably owing to its high hydrophobicity in addition to its binding with serum albumin. The longer residence of vanadyl species shows the higher normoglyceric effects of VO(IPA)2 among three complexes with the VO(N2O2) coordination mode. On the basis of these results, VO(IPA)2 is indicated to be a preferred agent to treat insulin-dependent diabetes mellitus in experimental animals. 相似文献
103.
Noblía P Vieites M Torre MH Costa-Filho AJ Cerecetto H González M Lavaggi ML Adachi Y Sakurai H Gambino D 《Journal of inorganic biochemistry》2006,100(2):281-287
As a contribution to the development of novel vanadyl complexes with potential insulin-mimetic activity, three new oxovanadium(IV) complexes with the formula VO(L)(2), where L are 3-amino-quinoxaline-2-carbonitrile N(1),N(4)-dioxide derivatives, have been synthesized. Complexes have been characterized by elemental and thermal analyses, fast atom bombardment mass spectroscopy (FAB-MS), conductivity measurements and electronic, Fourier transform infrared (FTIR) and electron paramagnetic resonance (EPR) spectroscopies. The in vitro insulin-mimetic activity of the vanadyl complexes has been estimated by lipolysis inhibition tests, in which the inhibition of the release of free fatty acid from isolated rat adipocytes treated with epinephrine was determined. All the complexes showed inhibitory effects on free fatty acid release. [V(IV)O(3-amino-6(7)-bromoquinoxaline-2-carbonitrile N(1),N(4)-dioxide)(2)] exhibited higher in vitro insulin-mimetic activity than the very active bis(6-methylpicolinato)oxovanadium(IV), VO(6mpa)(2). This new vanadyl complex is expected to exhibit a higher blood glucose lowering activity than VO(6mpa)(2) in diabetic animals. 相似文献
104.
Jing Lu Huanying Zheng Xue Guo Yong Zhang Hui Li Leng Liu Hanri Zeng Ling Fang Yanling Mo Hiromu Yoshida Lina Yi Tao Liu Shannon Rutherford Wenbo Xu Changwen Ke 《Applied and environmental microbiology》2015,81(7):2311-2319
An aseptic meningitis outbreak occurred in Luoding City of Guangdong, China, in 2012, and echovirus type 30 (ECHO30) was identified as the major causative pathogen. Environmental surveillance indicated that ECHO30 was detected in the sewage of a neighboring city, Guangzhou, from 2010 to 2012 and also in Luoding City sewage samples (6/43, 14%) collected after the outbreak. In order to track the potential origin of the outbreak viral strains, we sequenced the VP1 genes of 29 viral strains from clinical patients and environmental samples. Sequence alignments and phylogenetic analyses based on VP1 gene sequences revealed that virus strains isolated from the sewage of Guangzhou and Luoding cities matched well the clinical strains from the outbreak, with high nucleotide sequence similarity (98.5% to 100%) and similar cluster distribution. Five ECHO30 clinical strains were clustered with the Guangdong environmental strains but diverged from strains from other regions, suggesting that this subcluster of viruses most likely originated from the circulating virus in Guangdong rather than having been more recently imported from other regions. These findings underscore the importance of long-term, continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses. 相似文献
105.
Isolation,characterization, and cDNA sequence of a carotenoid binding protein from the silk gland of Bombyx mori larvae 总被引:6,自引:0,他引:6
Tabunoki H Sugiyama H Tanaka Y Fujii H Banno Y Jouni ZE Kobayashi M Sato R Maekawa H Tsuchida K 《The Journal of biological chemistry》2002,277(35):32133-32140
A carotenoid binding protein (CBP) has been isolated from the silk glands of Bombyx mori larvae. The protein has an apparent molecular mass of 33 kDa and binds carotenoids in a 1:1 molar ratio. Lutein accounts for 90% of the bound carotenoids, whereas alpha-carotene and beta-carotene are minor components. Immunological analysis demonstrated the presence of CBP only in the yellow-colored tissues of the silk gland, midgut, testis, and ovary. Several phenotypes of B. mori mutants linked to carotenoid transport have been utilized to characterize CBP. The Y (yellow hemolymph) gene controls uptake of carotenoids from the midgut lumen into the midgut epithelium, and larvae with the +(Y) gene lack this property. Immunoblotting analysis confirmed the presence of CBP in mutants with the dominant Y gene only. Immunohistochemistry verified the localization of CBP in the villi of the midgut epithelium, indicating that CBP might be involved in absorption of carotenoids. A cDNA clone for CBP encoding a protein of 297 amino acids has been isolated from the B. mori silk gland cDNA library. The deduced amino acid sequence revealed that CBP is a novel member of the steroidogenic acute regulatory (StAR) protein family with its unique structural feature of a StAR-related lipid transfer domain, known to aid in lipid transfer and recognition. Lutein-binding capacity of the recombinant CBP (rCBP) determined by incubating rCBP with lutein followed by immunoprecipitation using anti-CBP IgG conjugated to protein A-Sepharose, demonstrated the formation of a lutein-rCBP complex. Sequence analyses coupled with binding specificity suggest that CBP is a new member of the StAR protein family that binds carotenoids rather than cholesterol. 相似文献
106.
Koji Takechi Hideyuki Tamura Kiyoshi Yamaoka Hiromu Sakurat 《Free radical research》1997,26(6):483-496
In pharmacokinetic studies, a variety of analytical method including radioisotopic detection and HPLC (high performance liquid chromatography) has been used. In the present investigation, we developed in vivo BCM (Blood Circulation Monitoring)-ESR method, which is a new technique with a conventional X-band ESR spectrometer for observing stable free radicals in the circulating blood of living rats under anaesthesia. Both 5-(PROXYL derivatives) and 6-(TEMPO derivatives) membered nitroxide spin probes with various types of substituent functional group were used. After physicochemical properties of the spin probes such as hyperfine coupling constant (A-value), g-value and partition coefficient as well as chemical stability of the compounds in the fresh blood were obtained, the in vivo BCM-ESR method was performed in normal rats. Several pharmacokinetic parameters such as half-life of the probes, distribution volume, total body clearance and mean residence time were obtained and discussed in terms of their chemical structures. In addition, clearance of a spin probe was related to the urine concentration. The BCM-ESR method was found to be very useful to observe free radicals at the real time. By time-dependent ESR signal decay of spin probes, pharmacokinetic parameters were obtained. 相似文献
107.
Shuji Kitagawa Hiroko Fujisawa Fujio Kametani Hiromu Sakurai 《Free radical research》1992,15(6):319-324
Generation of active oxygen species by bovine blood platelets was examined by the electron spin resonance (ESR) spin trapping technique with 5,5-dimethyl-l-pyroline-l-oxide (DMPO). The hydroxyl spin-trapped adduct 5,5-dimethyl-2-hydroxy-l-pyrolidinyloxy (DMPO-OH) was formed in the presence of platelets, indicating the generation of hydroxyl radicals (· OH) by the platelets. Generation of · OH was observed even with platelets in the resting state, but was markedly enhanced when the platelets were activated with stimulants. Stronger stimulants such as the calcium ionophore ionomycin, induced greater radical gener-ation than the weaker stimulant ADP. When the platelets were stimulated by thrombin, generation of · OH was greatest after l.5 min, and depended on the dose of the stimulant. It was inhibited by inhibitors of platelet activation such as forskolin and phenolic antioxidants. 相似文献
108.
Helical conformations of infinite polymer chains may be described by the helical parameters, d and θ (the translation along the helix axis and the angle of rotation about the axis per repeat unit), pi (the distance of the ith atom from the axis), dij, and dij (the translation along the axis and the angle of rotation, respectively, on passing from the ith atom to the jth). A general method has been worked out for calculating all those helical parameters from the bond lengths, bond angles, and internal-rotation angles. The positions of the main chain and side chain atoms with respect to the axis may also be calculated. All the equations are applicable to any helical polymer chain and are readily programmed for electronic computers. A method is also presented for calculating the partial derivatives of helical parameters with respect to molecular parameters. 相似文献
109.
110.
Taxonomic analysis of a group of morphologically similar and phylogenetically related ponyfishes (Perciformes: Leiognathidae) establishes the Equulites elongatus species group comprising three valid species: Equulites aethopos sp. nov., currently known only from southern Red Sea; Equulites elongatus (Günther 1874), known from northern Australia, Indonesia and Myanmar; and Equulites popei (Whitley 1932), known from Japan, Philippines, Malaysia (Sabah), Thailand (Gulf of Thailand), Oman, the Red Sea, and Mozambique. Although E. popei has previously been regarded as a junior synonym of E. elongatus, the present mitochondrial DNA analysis revealed that these two nominal species are different and that they constitute a monophyletic group separate from other species of Equulites. The E. elongatus species group can be defined by the following of characters: slender body (20–30% in standard length), deeply incised posterior margin of the adipose eyelid, and ventral surface of breast completely scaly. Equulites aethopos sp. nov. differs from the other two species in having smaller eyes (eye diameter 53–68% of postorbital head length vs. 78–137%) and tips of neural and hemal spines of the fourth preural centrum distinctly expanding (vs. slightly expanding). Equulites elongatus is distinguished from E. popei by: scales above and below the lateral line 5–9 and 9–14, respectively (vs. 8–13 and 12–19), anus anteriorly located (distance from the pelvic-fin insertion to the center of anus 30–42% of the distance from the pelvic-fin insertion to the anal-fin origin vs. 35–50%), and more numerous dorsolateral dark marks (1–9 ring marks and 0–14 dark spots smaller than a half of pupil diameter vs. 0–2 and 0–5). 相似文献