全文获取类型
收费全文 | 15845篇 |
免费 | 1688篇 |
国内免费 | 3篇 |
出版年
2021年 | 189篇 |
2020年 | 167篇 |
2019年 | 221篇 |
2018年 | 323篇 |
2017年 | 260篇 |
2016年 | 459篇 |
2015年 | 715篇 |
2014年 | 786篇 |
2013年 | 933篇 |
2012年 | 1158篇 |
2011年 | 1089篇 |
2010年 | 759篇 |
2009年 | 609篇 |
2008年 | 878篇 |
2007年 | 813篇 |
2006年 | 754篇 |
2005年 | 676篇 |
2004年 | 717篇 |
2003年 | 586篇 |
2002年 | 551篇 |
2001年 | 321篇 |
2000年 | 288篇 |
1999年 | 237篇 |
1998年 | 152篇 |
1997年 | 137篇 |
1996年 | 109篇 |
1995年 | 110篇 |
1994年 | 128篇 |
1993年 | 115篇 |
1992年 | 184篇 |
1991年 | 191篇 |
1990年 | 174篇 |
1989年 | 186篇 |
1988年 | 166篇 |
1987年 | 156篇 |
1986年 | 154篇 |
1985年 | 139篇 |
1984年 | 118篇 |
1983年 | 96篇 |
1982年 | 96篇 |
1981年 | 101篇 |
1980年 | 92篇 |
1979年 | 106篇 |
1978年 | 106篇 |
1977年 | 67篇 |
1976年 | 85篇 |
1975年 | 96篇 |
1974年 | 94篇 |
1973年 | 86篇 |
1972年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
991.
992.
993.
Metabolic Processes in Cytoplasmic Particles of the Avocado Fruit. IX. The Oxidation of Pyruvate and Malate during the Climacteric Cycle 总被引:8,自引:7,他引:1 下载免费PDF全文
Mitochondria isolated from preclimacteric avocado fruit oxidize pyruvate at a much lower rate than those separated from climacteric fruit. The external addition of thiamine pyrophosphate (TPP) increased the rate of pyruvate oxidation in both cases.The study of the influence of TPP on the rate of oxidation of malate by mitochondria obtained from both preclimacteric and climacteric fruit indicated that the effect of this cofactor could be understood by assuming that malate was converted to pyruvate. TPP stimulation of malate oxidation was prevented by arsenite, an inhibitor of keto acid oxidation. The addition of glutamate increased the rate of malate oxidation through the transamination of oxaloacetate. This suggests that the rate of oxidation of malate is highly dependent upon mechanisms which remove oxaloacetate efficiently.Incubation of mitochondria from preclimacteric fruit with malate-U-(14)C resulted in the labeling of oxaloacetate and the accumulation of labeled pyruvate. Addition of TPP to this system induced the rapid formation of citrate. This conversion was completely inhibited by arsenite.The results indicate that the ability to carry out the oxidative decarboxylation of alpha-ketoacids improves as the ripening process progresses. The idea was advanced that TPP available to the mitochondria plays an important controlling role. 相似文献
994.
Autolytic enzyme associated with cell walls of Bacillus subtilis 总被引:31,自引:0,他引:31
F E Young 《The Journal of biological chemistry》1966,241(15):3462-3467
995.
996.
997.
998.
999.
Lysogenic Conversion in Bacillus amyloliquefaciens H Affecting Viral Adsorption 总被引:3,自引:2,他引:1 下载免费PDF全文
Lysogenization of Bacillus amyloliquefaciens H with bacteriophage PK renders the bacteria resistant to superinfection with bacteriophage of PK type. 相似文献
1000.
Mannitol, sucrose, and laminitol have been isolated from ethanolic extracts of the brown seaweed Desmarestia aculeata and characterised, and rhamnose, sedoheptulose, glucose, fructose, and 2-O-methyl- and 3-O-methyl-fucose have been identified by their chromatographic mobilities and g.l.c. retention times. Laminarin, alginic acid, and “fucans” were isolated also and characterised. The laminarin contained 1.7% of mannitol end-groups, and the fucans a relatively high proportion of galactose which was present as end-group and (1→3)-linked units. 相似文献