全文获取类型
收费全文 | 189篇 |
免费 | 12篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 5篇 |
2014年 | 8篇 |
2013年 | 15篇 |
2012年 | 9篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 5篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 13篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有201条查询结果,搜索用时 562 毫秒
1.
Summary The presence of a Ca2+ channel in the plasmalemma of tonoplast-freeNitellopsis obtusa cells was demonstrated and its characteristics were studied using current- and voltage-clamp techniques. A long-lasting inward membrane current (I
m
), recorded using a step voltage clamp, consisted of a single component without time-dependent inactivation. Increasing either [Ca2+]
o
or [Cl–]
o
1) enhanced the maximum amplitude of inwardI
m
((I
m
)
p
) and 2) shifted the peak voltage ((V
m
)
p
) at(I
m
)
p
to more positive values under ramp-shaped voltage clamping and 3) depolarized the peak value of action potentials. This behavior is consistent with predictions based on the Nernst equation for Ca2+ but not for Cl–. DIDS (4,4-diisothiocyano-2,2-disulfonic acid stilbene) did not suppress(I
m
)
p
in tonoplast-free cells, in contrast with its effect on normal cells. La3+ and nifedipine blocked(I
m
)
p
irreversibly. On the other hand, Ca2+ channel agonist, BAY K 8644 irreversibly enhanced(I
m
)
p
. Both Sr2+ influx and K+ efflux increased upon excitation. The charge carried by Sr2+ influx was compensated for by K+ efflux. It is concluded that only the Ca2+ channel is activated during plasmalemma excitation in tonoplast-free cells. In terms of the magnitude of(I
m
)
p
, Sr2+ could replace Ca2+, but Mn2+, Mg2+ and Ba2+ could not. External pH affected(I
m
)
p
and the membrane conductance (g
m
) at(I
m
)
p
((g
m
)
p
). Increasing the external ionic strength caused increases in both(I
m
)
p
and(g
m
)
p
, and shifted(V
m
)
p
to positive values. At the same time, Sr2+ influx increased. Thus Ca2+ channel activation seems to be enhanced by increasing external ionic strength. The possible involvement of surface potential is discussed. 相似文献
2.
Summary In order to demonstrate the presence of a Ca2+-activated Cl–-channel in theNitellopsis plasmalemma, tonoplast-free cells were prepared and their intracellular Ca2+ concentration was modified by internal perfusion. An increase in the Ca2+ concentration caused a large Cl– efflux with a concomitant depolarization of the membrane potential. These changes were for the most part reversible. The critical Ca2+ concentration was about 4.0 m. Neither the Cl– efflux nor the membrane depolarization showed a time-dependent inactivation. A Cl–-channel blocker, A-9-C (9-anthracenecarboxylic acid) reduced both the Cl– efflux and the magnitude of the membrane potential depolarization. A small increase in the intracellular Ca2+ concentration, which is caused by membrane excitation of tonoplast-free cells is not sufficient to activate this Ca2+-dependent Cl–-channel. 相似文献
3.
The mechanism of end-organ resistance to 1 alpha,25-dihydroxycholecalciferol in the common marmoset. 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《The Biochemical journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
N Takahashi S Suda T Shinki N Horiuchi Y Shiina Y Tanioka H Koizumi T Suda 《The Biochemical journal》1985,227(2):555-563
The common marmoset, a New World monkey, requires a large amount of cholecalciferol (110 i.u./day per 100g body wt.) to maintain its normal growth. In a previous report, we demonstrated that the circulating levels of 1 alpha, 25-dihydroxycholecalciferol [1 alpha,25(OH)2D3] in the marmosets are much higher than those in rhesus monkeys and humans, but the marmosets are not hypercalcaemic [Shinki, Shiina, Takahashi, Tanioka, Koizumi & Suda (1983) Biochem. Biophys. Res. Commun. 14, 452-457]. To compare the effect of the daily intake of cholecalciferol, two rhesus monkeys were given a large amount of cholecalciferol (900 i.u./day per 100g body wt). Their serum levels of calcium, 25-hydroxycholecalciferol and 24R,25-dihydroxycholecalciferol were markedly elevated, but the serum 1 alpha,25(OH)2D3 levels remained within a range similar to those in the rhesus monkeys fed the normal diet (intake of cholecalciferol 5 i.u./day per 100g body wt). Intestinal cytosols prepared from both monkeys contained similar 3.5 S macromolecules to which 1 alpha,25(OH)2D3 was bound specifically. However, the cytosols from the marmosets contained only one-sixth as many 1 alpha,25(OH)2D3 receptors as those from the rhesus monkeys. Furthermore, the activity of the 1 alpha,25(OH)2D3-receptor complex in binding to DNA-cellulose was very low in the marmosets. These results suggest that the marmoset possesses an end-organ resistance to 1 alpha,25(OH)2D3 and is a useful animal model for studying the mechanism of vitamin D-dependent rickets, type II. 相似文献
4.
5.
6.
7.
The results of our present study indicate that 1 alpha, 25-dihydroxyvitamin D3[1 alpha, 25(OH)2D3] directly induces fusion of mouse alveolar macrophages without any participation of T-lymphocytes by a mechanism involving RNA and protein synthesis but not DNA synthesis. We have reported that 1 alpha, 25(OH)2D3 induces fusion of alveolar macrophages by a direct mechanism and by a spleen cell-mediated indirect mechanism [(1983) Proc. Natl. Acad. Sci. USA 80, 5583-5587]. Alveolar macrophages pretreated with or without anti-Thy 1.2 antibody and complement fused similarly when they were incubated with 1 alpha, 25(OH)2D3. The vitamin suppressed DNA synthesis, but it significantly enhanced RNA and protein synthesis. The 1 alpha, 25(OH)2D3-induced fusion was blocked by adding actinomycin D or cycloheximide, but not by hydroxyurea. 相似文献
8.
9.
Effects of heat treated cells of intestinal lactic acid bacteria in rats fed a deoxycholic acid diet
Effects of the administration of heat treated cells of intestinal lactic acid bacteria were examined in rats fed a deoxycholic acid (DCA) diet. Male Wistar rats were given a 0.25% DCA diet with or without the heat treated cells of Enterococcus faecalis AD 1001 (EFH-1) or Lactobacillus reuteri AD 0002 (LRH-2) for 4 weeks. Abnormal increases in serum GOT, GPT, UN and lipoproteins were observed in the rats fed the DCA diet. Furthermore, severe lesions in the kidney as well as in the liver were found in these rats. On the contrary, the increases in serum GOT, UN, VLDL and LDL were significantly suppressed, and markedly fewer lesions in the liver and the kidney were observed in the rats fed the DCA diet plus EFH-1 or LRH-2. 相似文献
10.
Jin-Yong Ha Mineo Saneyoshi Ho-Dong Park Hideshige Toda Satoshi Kitano Takamitsu Homma Takehito Shiina Yutaka Moriyama Kwang-Hyeon Chang Takayuki Hanazato 《Limnology》2013,14(1):19-30
Biomanipulation has been employed in numerous locations throughout the world as a means for reducing phytoplankton biomass; however, it has not been employed very often in Japan. A common approach involves the introduction of piscivorous fish to reduce the abundance of planktivorous fish. In our study, to first apply biomanipulation, we stocked Lake Shirakaba (a high-altitude, protected area in a park) in central Japan with rainbow trout fingerlings and cladoceran Daphnia (Daphnia galeata) in 2000. A “pre-biomanipulation” data set (1997–1999) and “a post-biomanipulation” data set (2000–2006) allowed us to evaluate the lake's response to biomanipulation. After the biomanipulation, zoo-planktivorous pond smelt disappeared and a large population of Daphnia had been established, which substantially reduced the number of the previously dominant small cladocerans and rotifers. Water transparency increased from about 2 m (before biomanipulation) to more than 4 m (after biomanipulation). Reductions in algal biomass and increased transparency led to expansion of the submerged macrophyte Elodea nuttallii. Total phosphorus concentrations declined as well over this time period. Based on these results, we concluded that biomanipulation using piscivore and Daphnia stocking succeeded in improving lake water quality by reducing algal abundance and providing favorable conditions for the establishment of rooted plants. 相似文献