全文获取类型
收费全文 | 1380篇 |
免费 | 98篇 |
专业分类
1478篇 |
出版年
2023年 | 7篇 |
2022年 | 18篇 |
2021年 | 43篇 |
2020年 | 26篇 |
2019年 | 39篇 |
2018年 | 51篇 |
2017年 | 31篇 |
2016年 | 47篇 |
2015年 | 58篇 |
2014年 | 80篇 |
2013年 | 80篇 |
2012年 | 73篇 |
2011年 | 79篇 |
2010年 | 57篇 |
2009年 | 46篇 |
2008年 | 50篇 |
2007年 | 72篇 |
2006年 | 46篇 |
2005年 | 53篇 |
2004年 | 32篇 |
2003年 | 34篇 |
2002年 | 34篇 |
2001年 | 20篇 |
2000年 | 27篇 |
1999年 | 16篇 |
1998年 | 10篇 |
1997年 | 7篇 |
1995年 | 12篇 |
1994年 | 11篇 |
1992年 | 13篇 |
1991年 | 25篇 |
1990年 | 16篇 |
1989年 | 27篇 |
1988年 | 11篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 10篇 |
1982年 | 17篇 |
1981年 | 10篇 |
1980年 | 10篇 |
1979年 | 22篇 |
1978年 | 11篇 |
1977年 | 15篇 |
1975年 | 14篇 |
1974年 | 6篇 |
1973年 | 10篇 |
1972年 | 9篇 |
1971年 | 7篇 |
排序方式: 共有1478条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
A. C. Shukla 《Hydrobiologia》1967,30(2):221-224
Effect of presoaking seeds with different concentrations (0.5, 1 and 5%) of algal extracts on the development of stomata and epidermal cells in rice leaves has been investigated. One percent ether extract of Phormidium foveolarum (Mont.) Gomont suspended in water increases the number of stomata and also the total perimeter of stomatal pores, suggesting that the plants are better adopted for photosynthetic activity. 相似文献
5.
6.
Shivendra D. Shukla 《Life sciences》1982,30(16):1323-1335
The role of phosphatidylinositol-specific phospholipase C (PIase C) in a) the enigmatic phosphatidylinositol (PI) turnover and b) in our understanding of membrane enzyme-PI interactions is the subject matter of this article. PIase C is present in both procaryotes and eukaryotes. This enzyme is considered to be involved in the cells PI breakdown which occurs in response to several external stimuli. Recent information on the physical properties, Ca2+ requirement, cellular localization and modulation of the activity of PIase C of mammalian systems can help to evaluate the PI turnover from a new angle. Existing evidence suggests that Ca2+-dependent PI breakdown is probably mediated through the cytosolic and particulate PIase C while a Ca2+ independent pathway is catalyzed by a lysosomal enzyme. Apparently PI turnover may be operating through more than one mechanism. The association of this phenomenon with a membrane receptor event linked with “Ca2+ gating” may have to be reconsidered. Modulation of the PIase C activity by unsaturated amphiphiles or the presence of this enzyme in different physico-chemical forms could be a potential regulatory feature.Hydrolysis of membrane PI of a number of cells and tissues by the bacterial PIase C has been shown to cause substantial release of acetylcholinesterase, alkaline phosphatase and 5′-nucleotidase in free, soluble form. Other membrane enzymes, e.g., alkaline phosphodiesterase I, L-leucyl-β naphtyl amidase and Ca2+ or Mg2+ ATPase are not affected. These results indicate a specific interaction between PI and certain enzymes in membranes. The chemical nature of this linkage, whether it is covalent or non-covalent, has also been explored and has provided intriguing insight into this phenomenon. New findings also indicate that hydrolysis of PI by PIase C also can cause modifications in membrane-enzyme activities, e.g., adenylate cyclase. 相似文献
7.
Two new compounds G and H isolated from the roots of Costus speciosus have been characterized as 8-hydroxytriacontan-25-one and Me tritriacontanoat 相似文献
8.
9.
Shukla RN 《Biochemistry and experimental biology》1977,13(4):411-416
Proteins and lipids in the haemolymph in both the sexes of the Danais chrysippus has been observed during the first gonotropic cycle. The concentration fluctuations in these haemolymph metabolites are correlated with the physiological state of the insect. The total protein and lipid concentration in the haemolymph of unmated females have been found to be low than the concentration found for the normal females although it followed the same type of oscillations in the concentration as have been observed for normal females. 相似文献
10.
Chiranjib Banerjee Rajib Bandopadhyay Pratyoosh Shukla 《Indian journal of microbiology》2012,52(4):710-712
A simple agar diffusion method is developed where pure colony of Chlamydomonas sp. CRP7 was isolated from Chlorella sp. CB4 mixtures by passing through agar migration with a light exposure of 6,000 lux for 7 h. The main concept behind it is that Chlamydomonas has flagella and the rhodopsin pigment is attracted towards light. Thus the above two microalgae species can be separated from the mixtures as eye spot serves as a navigator and flagella serves as a propeller for Chlamydomonas spp. Further the genomic DNA was isolated and purified from the above mentioned two species after the separation from the mixtures. PCR amplification was carried out for ITS1, 5.8S and ITS2 regions. The amplified products were sequenced and the sequence analysis confirmed that they belong to Chlamydomonas sp. and Chlorella sp. This is an important augmentation for isolation and separation of microalgae. 相似文献