全文获取类型
收费全文 | 141篇 |
免费 | 2篇 |
国内免费 | 2篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 10篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有145条查询结果,搜索用时 15 毫秒
141.
Irene E. Stith Salil K. Das 《Biochimica et Biophysica Acta (BBA)/General Subjects》1982,714(2):250-256
Development of mitochondrial and microsomal choline phosphotransferase in the fetal guinea pig lung was investigated. The activity in fetal mitochondria was more than twice of that in fetal microsomes. However, in adult lung, the enzyme was distributed mostly in microsomes. In fetal lung, both the mitochondrial and microsomal enzyme activity was greatest at approx. 81% of the total gestation period (55 days). The specific activity in the microsomal fraction then declined until term, but increased again in the 24-h newborn from 1.0 to 2.3 nmol/min per mg protein. The activity in the mitochondrial fraction declined after 61 days (2.8 nmol/min per mg) to a minimal level at term (0.6 nmol/min per mg). Although the enzyme activity decreased from day 55 (1.2 nmol/min per mg), the amount of phosphatidylcholine gradually increased between day 55 and term. 相似文献
142.
When methyl parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate), an organophosphorous insecticide, was added to an exponentially
growing culture ofChlorella protothecoides and the effects were followed for 12 days, the following observations were made: a) In autotrophic culture the cell number
and the chlorophyll content decreased as compared to the control. These changes paralleled the inhibition of the rate of net
photosynthesis, suggesting that the photosynthetic apparatus was the primary target of the insecticide action. b) The inhibition
of cell growth (on cell number basis) also occurred in the case of heterotrophic culture at 100μM insecticide concentration
but the inhibition was less as compared to that of an autotrophic culture. c) The cell diameter in treated culture increased
by 10–20% in both autotrophic and heterotrophic cultures. The observations, (b) and (c) suggest that apart from the photosynthetic
apparatus, the insecticide has other sites of action, but the sensitivity of these sites to the insecticide is less than that
of the photosynthetic apparatus 相似文献
143.
Exposure of the red alga Porphyra
perforata or leaves of Phytolacca
americana and Echinodorus sp. to white light equivalent to full sunlight for short periods induced large decreases of variable fluorescence measured at 695 nm at 77K. This change was not produced by photoinhibition but rather appeared to result from an inorease in the rate constant of radiationless transition in the reaction centers of photosystem II. It is proposed that this increase is related to the formation of the high energy state which serves as a photoprotective mechanism in plants. 相似文献
144.
Chlorophyll a (Chl a) fluorescence-temperature profile in the region of 20–80°C was recorded for fourteen different plant species. In all the species studied, there was a rise in the fluorescence intensity in the region of 45–50°C and around 55°C the fluorescence intensity started to decline. In four of the species (Acacia melanoxylon, Ervatamia montana, Eucalyptus tertecornius and Azardicta indica) tested, there was a secondary rise in the fluorescence intensity around 65–70°C whereas in all other species a sharp decline in the fluorescence intensity was observed at this point. These changes in the fluorescence intensity at high temperatures (65–70°C) appear to be species specific and cannot be explained either in terms of changes in the stoichiometry between the two photosystems or in terms of Chl a fluorescence emission from photosystem I (PS I) at higher temperatures. This conclusion is supported by following observations: (1) there was no definite correlation between the Chl a/Chl b ratio and the pattern of fluorescence-temperature profile at high temperatures; (2) the sun and shade plants of the same species had a similar pattern of fluorescence-temperature profile; and (3) preferential excitation of PS I did not alter the fluorescence-temperature profile.Abbreviations Chl
chlorophyll
- PS
photosystem 相似文献
145.
The levels of free amino acids were determined in human foetal brain regions during prenatal development. Variation in the distribution of amino acids and their rate of change in five segments of the CNS at different stages of ontogeny was observed. Striking developmental changes were found in the levels of aspartic acid in medulla-pons and spinal cord, glycine in the spinal cord, gamma-aminobutyric acid in the cerebral cortex, glutamic acid in the cerebral cortex, midbrain, and spinal cord, and taurine in the medulla-pons and spinal cord. At a late gestational period, glutamic acid was found most abundantly over all the brain regions, whereas the level of taurine was highest at an early gestational stage but not in spinal cord. 相似文献