全文获取类型
收费全文 | 175篇 |
免费 | 2篇 |
专业分类
177篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 7篇 |
2012年 | 8篇 |
2011年 | 6篇 |
2010年 | 10篇 |
2009年 | 2篇 |
2008年 | 5篇 |
2007年 | 6篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 8篇 |
2003年 | 12篇 |
2002年 | 12篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1974年 | 5篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有177条查询结果,搜索用时 0 毫秒
141.
Nicholas?H?CarbonettiEmail author R?Michael?Mays Galina?V?Artamonova Roger?D?Plaut Zo??EV?Worthington 《BMC microbiology》2005,5(1):7
Background
Pertussis toxin (PT) is an exotoxin virulence factor produced by Bordetella pertussis, the causative agent of whooping cough. PT consists of an active subunit (S1) that ADP-ribosylates the alpha subunit of several mammalian G proteins, and a B oligomer (S2–S5) that binds glycoconjugate receptors on cells. PT appears to enter cells by endocytosis, and retrograde transport through the Golgi apparatus may be important for its cytotoxicity. A previous study demonstrated that proteolytic processing of S1 occurs after PT enters mammalian cells. We sought to determine whether this proteolytic processing of S1 is necessary for PT cytotoxicity. 相似文献142.
Zhorova ES Il'in LA Ivannikov AT Popov BA Parfenova IM 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2002,42(5):520-525
Effect of different cincacine doses was studied in rats ingesting americium citrate during 2 weeks. As a result new data showing the possibility and efficacy of per oral cincacine administration at americium intake into digestive tract have been obtained. Dose dependence of cincacine efficacy has been stated for per oral 241Am intake. Preparation administration at a dose of 25 mumol/kg reduces amount of 241Am in skeleton, liver and kidney by 93, 90 and 33%, respectively and is optimum for radionuclide removal from the body and for the prevention of its deposition in organs. Digestive system organs and kidney structure at cincacine administration at a dose of 150 and 300 mumol/kg) to the rats ingesting 241Am have been studied. 相似文献
143.
144.
Stepanova IIu Eprintsev AT Falaleeva MI Parfenova NV Grabovich MIu Patritskaia VIu Dubinina GA 《Mikrobiologiia》2002,71(4):445-451
Major pathways of carbon metabolism were studied in strains D-402 and D-405 of freshwater colorless sulfur bacteria of the genus Beggiatoa grown organotrophically and mixotrophically. The bacteria were found to possess all the enzymes of the tricarboxylic acid (TCA) and glyoxylate cycles. When organotrophic growth changed to mixotrophic one, the activity of the TCA cycle enzymes decreased 2- to 3-fold, but the activity of enzymes of the glyoxylate cycle increased threefold. It follows that, in the oxidation of thiosulfate, organic compounds no longer play the leading part in the energy metabolism, and most of electrons that enter the electron transport chain (ETC) derive from inorganic sulfur compounds. A connection was established between the structure and kinetic characteristics of malate dehydrogenase--an enzyme of the TCA and glyoxylate cycles--and the type of carbon metabolism in the strains studied. Malate dehydrogenase in organotrophically grown cells of strains D-402 and D-405 is dimeric, whereas in strain D-402 grown mixotrophically it is tetrameric. 相似文献
145.
Fiumana E Parfenova H Jaggar JH Leffler CW 《American journal of physiology. Heart and circulatory physiology》2003,284(4):H1073-H1079
The excitatory neurotransmitter glutamate causes dilation of newborn pig cerebral arterioles in vivo that is blocked by inhibition of carbon monoxide (CO) production. CO, a potent dilator in cerebral circulation in vivo, is produced endogenously in cerebral microvessels via heme oxygenase (HO). In isolated pressurized cerebral arterioles (approximately 200 microm) from newborn pigs, we investigated the involvement of CO and the endothelium in response to glutamate. A CO-releasing molecule, dimanganese decacarbonyl (10(-8)-10(-6) M), dilated cerebral arterioles. Glutamate (10(-6)-10(-4) M) and 1-aminocyclopentane-cis-1,3-dicarboxylic acid (cis-ACPD; 10(-6)-10(-5) M), a N-methyl-D-aspartate (NMDA) receptor agonist, caused cerebral vascular dilation. Dilation of cerebral arterioles to glutamate and cis-ACPD was abolished by chromium mesoporphyrin (CrMP; 10(-6) M), a HO inhibitor. In contrast, CrMP did not alter dilation to isoproterenol, a -adrenergic receptor agonist. Endothelium-denuded cerebral arterioles did not dilate to glutamate or bradykinin (endothelium-dependent dilator), whereas responses to isoproterenol were preserved. These data indicate that cerebral arterioles from newborn pigs may directly respond to glutamate and the NMDA receptor agonists by endothelium-dependent dilation that involves stimulation of CO production via the HO pathway in the endothelium. 相似文献
146.
147.
148.
Savchenko Rimma G. Veskina Natalya A. Odinokov Viktor N. Benkovskaya Galina V. Parfenova Lyudmila V. 《Phytochemistry Reviews》2022,21(5):1445-1486
Phytochemistry Reviews - Ecdysteroids are polyhydroxylated sterols, and are widespread in the plant and animal world. To date, over 520 ecdysteroids have been isolated from natural sources. The... 相似文献
149.
Leffler CW Fedinec AL Parfenova H Jaggar JH 《American journal of physiology. Heart and circulatory physiology》2005,289(1):H432-H438
Endogenously produced CO is an important dilator in newborn cerebrovascular circulation. CO dilates cerebral arterioles by activating Ca2+-activated K+ channels, but modulatory actions of other effectors and second messenger inputs are unclear. Specifically, the mechanisms behind the obligatory permissive roles of prostacyclin and NO are uncertain. Therefore, the present study was performed using acutely implanted, closed cranial windows in newborn pigs to address the hypothesis that the permissive roles of NO and prostacyclin in cerebrovascular dilation in response to CO involve a common mechanism. The NO donor sodium nitroprusside restored dilation in response to CO after inhibition of that dilation with the prostaglandin cyclooxygenase inhibitor indomethacin. The stable prostacyclin analog iloprost restored CO-induced dilation blocked by the NO synthase inhibitor Nomega-nitro-L-arginine. Restoration of dilation in response to CO by the cGMP-dependent phosphodiesterase inhibitor zaprinast and blockade of CO dilation by the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazole-[4,3-a]quinoxalin-1-one (ODQ) suggests involvement of the cGMP/PKG pathway. Iloprost or the cAMP-dependent dilator isoproterenol restored dilation in response to CO after ODQ administration. However, CO-induced dilation blocked by the cGMP-dependent PKG inhibitor Rp-8-[(4-chlorophenyl)thio]-cGMPS triethylamine could not be reversed by administration of sodium nitroprusside, iloprost, or isoproterenol. Conversely, PKA inhibition did not block dilation in response to CO. Overall, data indicate that activation of PKG is the predominant mechanism of the permissive actions of NO and prostacyclin for CO-induced pial arteriolar dilation. 相似文献
150.
Almir S Zanca Renato Vicentini Fausto A Ortiz-Morea Luiz EV Del Bem Marcio J da Silva Michel Vincentz Fabio TS Nogueira 《BMC plant biology》2010,10(1):260