全文获取类型
收费全文 | 8361篇 |
免费 | 561篇 |
出版年
2021年 | 65篇 |
2020年 | 36篇 |
2019年 | 64篇 |
2018年 | 91篇 |
2017年 | 69篇 |
2016年 | 109篇 |
2015年 | 176篇 |
2014年 | 200篇 |
2013年 | 433篇 |
2012年 | 362篇 |
2011年 | 396篇 |
2010年 | 223篇 |
2009年 | 223篇 |
2008年 | 413篇 |
2007年 | 375篇 |
2006年 | 420篇 |
2005年 | 409篇 |
2004年 | 398篇 |
2003年 | 390篇 |
2002年 | 400篇 |
2001年 | 304篇 |
2000年 | 303篇 |
1999年 | 252篇 |
1998年 | 113篇 |
1997年 | 101篇 |
1996年 | 90篇 |
1995年 | 90篇 |
1994年 | 96篇 |
1993年 | 96篇 |
1992年 | 173篇 |
1991年 | 180篇 |
1990年 | 169篇 |
1989年 | 157篇 |
1988年 | 151篇 |
1987年 | 129篇 |
1986年 | 108篇 |
1985年 | 88篇 |
1984年 | 113篇 |
1983年 | 87篇 |
1982年 | 55篇 |
1981年 | 51篇 |
1980年 | 66篇 |
1979年 | 98篇 |
1978年 | 71篇 |
1977年 | 79篇 |
1976年 | 47篇 |
1975年 | 42篇 |
1974年 | 49篇 |
1973年 | 45篇 |
1972年 | 44篇 |
排序方式: 共有8922条查询结果,搜索用时 31 毫秒
141.
142.
DNA polymerase associated with nuclear membrane of calf thymus 总被引:2,自引:0,他引:2
S Yoshida M J Modak K Yagi 《Biochemical and biophysical research communications》1971,43(6):1408-1414
143.
Hiroshi Ashihara Atsushi Komamine Masami Shimokoriyama 《Journal of plant research》1974,87(2):121-131
Changes in activities of the glycolytic and pentose phosphate (PP) pathways in glucose catabolism in various parts of the
hypocotyls obtained from 4-day-old etiolatedPhaseolus mungo seedlings were investigated by measuring the inhibition rates of respiration by iodoacetate and malonate, and the release
of14CO2 from [1-14C]- and [6-14C]glucose. The relative activity of the PP pathway in glucose catabolism was higher in the immature part (Part I) and the
aged part (Part V) of the hypocotyls than in the intermediary one (Part III), while the activity of the glycolytic pathway
decreased with aging.
On a fresh weight basis, the enzyme activities of the glycolytic and PP pathways were higher in Part I than in Parts III and
V. On a protein content basis, however, activities of the enzymes of the PP pathway increased with aging and differentiation
of the hypocotyls whereas those of the glycolytic pathway decreased. Levels of nicotinamide adenine nucleotides were found
to be in the following order: Part I>Part III> Part V for NAD++NADH; Part I>Part V>Part III for NADP++NADPH. The stimulative effect of methylene blue on decreasing the C6/C1 ratio was greater in Part III than in Part I, and No effect was observed in Part V.
These data suggest that a decrease in the activity of the glycolytic pathway with aging and differentiation may be due to
the decreasing glycolytic enzyme activities and NAD(H) content. The higher activity of the PP pathway in the immature part
is attributable to larger amounts of NADP(H) and enzymes of the PP pathway. The greater contribution of the PP pathway to
glucose catabolism in the aged part than in the intermediary part seems to results from a more active turnover of NADP and
the relatively higher activity of the enzymes of the PP pathway than those of the glycolytic pathway. 相似文献
144.
The nucleotide sequency of tRNA Gly from yeast 总被引:6,自引:0,他引:6
M Yoshida 《Biochemical and biophysical research communications》1973,50(3):779-784
Analysis of the factor for proximity and orientation is given for cyclopentadiene dimerization and for the general case of more complex biological molecules. Using either a probability or a statistical mechanical approach, the same ratios are obtained. The proximity effect factor is found to be about per reacting pair of molecules which show no net attraction or repulsion. The use of translational entropy without inclusion of a rotational entropy term gives a misleading value for this proximity factor. The calculations support the argument that orientation factors can play a large role in the catalytic power of enzymes. 相似文献
145.
146.
147.
148.
A novel composition of phosvitins from salmon and trout roe 总被引:1,自引:0,他引:1
149.