全文获取类型
收费全文 | 101篇 |
免费 | 8篇 |
专业分类
109篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2011年 | 2篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 1篇 |
2007年 | 3篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 4篇 |
1998年 | 6篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有109条查询结果,搜索用时 15 毫秒
71.
The ability of particular cell surface glycoproteins to recycle and become
exposed to individual Golgi enzymes has been demonstrated. This study was
designed to determine whether endocytic trafficking includes significant
reentry into the overall oligosaccharide processing pathway. The Lec1
mutant of Chinese hamster ovary (CHO) cells lack N -
acetylglucosaminyltransferase I (GlcNAc-TI) activity resulting in surface
expression of incompletely processed Man5GlcNAc2 N -linked
oligosaccharides. An oligosaccharide tracer was created by exoglycosylation
of cell surface glycoproteins with purified porcine GlcNAc-TI and
UDP-[3H]GlcNAc. Upon reculturing, all cell surface glycoproteins that
acquired [3H]GlcNAc were acted upon by intracellular mannosidase II, the
next enzyme in the Golgi processing pathway of complex N -linked
oligosaccharides (t1/2= 3-4 h). That all radiolabeled cell surface
glycoproteins were included in this endocytic pathway indicates a common
intracellular compartment into which endocytosed cell surface glycoproteins
return. Significantly, no evidence was found for continued oligosaccharide
processing consistent with transit through the latter cisternae of the
Golgi apparatus. These data indicate that, although recycling plasma
membrane glycoproteins can be reexposed to individual Golgi-derived
enzymes, significant reentry into the overall contiguous processing pathway
is not evident.
相似文献
72.
Electrophysiological evidence for involvement of cyclic adenosine monophosphate in dopamine responses of caudate neurons 总被引:1,自引:0,他引:1
Microiontophoresis of dopamine, apomorphine, cyclic adenosine monophosphate (cyclic AMP) and monobutyryl cyclic AMP depresses the spontaneous or drug-evoked discharge of the majority of neurons in the rat caudate nucleus. Responses to dopamine are enhanced only slightly by the phosphodiesterase (PDE) inhibitors aminophylline or papaverine, both of which also directly slow caudate neurons. However, iontophoresis of the PDE inhibitor methyl isobutyl xanthine (IBMX), or combination of IBMX and papaverine produced marked potentiations of dopamine-induced inhibitions. IBMX alone has little or no direct actions. Chlorpromazine, but not the beta adrenergic blocker MJ-1999, antagonized dopamine, but not cyclic AMP responses. After destruction of the nigral striatal dopamine bundle by focal injection of 6-hydroxy-dopamine, caudate neurons show supersensitivity to dopamine and apomorphine. These results provide electrophysiological support for the hypothesis that the dopamine receptor in caudate may be functionally related to the adenyl cyclase system, as suggested by recent biochemical findings. 相似文献
73.
74.
Junior Barrera Roberto M CesarJr Carlos HumesJr David C MartinsJr Diogo FC Patrão Paulo JS Silva Helena Brentani 《BMC bioinformatics》2007,8(1):169
Background
One goal of gene expression profiling is to identify signature genes that robustly distinguish different types or grades of tumors. Several tumor classifiers based on expression profiling have been proposed using microarray technique. Due to important differences in the probabilistic models of microarray and SAGE technologies, it is important to develop suitable techniques to select specific genes from SAGE measurements. 相似文献75.
76.
77.
78.
79.
Hashemy SI Ungerstedt JS Zahedi Avval F Holmgren A 《The Journal of biological chemistry》2006,281(16):10691-10697
Motexafin gadolinium (MGd) is a chemotherapeutic drug that selectively targets tumor cells and mediates redox reactions generating reactive oxygen species. Thioredoxin (Trx), NADPH, and thioredoxin reductase (TrxR) of the cytosol/nucleus or mitochondria are major thiol-dependent reductases with many functions in cell growth, defense against oxidative stress, and apoptosis. Mammalian TrxRs are selenocysteine-containing flavoenzymes; MGd was an NADPH-oxidizing substrate for human or rat TrxR1 with a Km value of 8.65 microM (kcat/Km of 4.86 x 10(4) M(-1) s(-1)). The reaction involved redox cycling of MGd by oxygen producing superoxide and hydrogen peroxide. MGd acted as a non-competitive inhibitor (IC50 of 6 microM) for rat TrxR. In contrast, direct reaction between MGd and reduced human Trx was negligible. The corresponding reaction with reduced Escherichia coli Trx was also negligible, but MGd was a better substrate (kcat/Km of 2.23 x 10(5) M(-1) s(-1)) for TrxR from E. coli and a strong inhibitor of Trx-dependent protein disulfide reduction. Ribonucleotide reductase (RNR), a 1:1 complex of the non-identical R1- and R2-subunits, catalyzes the essential de novo synthesis of deoxyribonucleotides for DNA synthesis using electrons from Trx and TrxR. MGd inhibited recombinant mouse RNR activity with either 3 microM reduced human Trx (IC50 2 microM) or 4 mM dithiothreitol (IC50 6 microM) as electron donors. Our results demonstrate MGd-induced enzymatic generation of reactive oxygen species by TrxR plus a powerful inhibition of RNR. This may explain the effects of the drug on cancer cells, which often overproduce TrxR and have induced RNR for replication and repair. 相似文献
80.
T Sharp T Zetterstr?m H G Series A Carlsson D G Grahame-Smith U Ungerstedt 《Life sciences》1987,41(7):869-872
This short article reviews HPLC-EC methodology that we are currently applying to measure DA, 5-HT and their acid metabolites in rat brain dialysates collected in vivo. HPLC-EC systems based on standard-bore HPLC columns are described which are sufficiently sensitive to allow detection of the monoamine transmitters and their metabolites in regional brain dialysates collected at 10-20 min intervals. A large reduction in sample requirement was achieved by "down-scaling" the conventional HPLC-EC assay to incorporate small-bore HPLC columns. The small-bore systems allowed monoamines to be detected in samples collected over 1 to a few minutes. 相似文献