全文获取类型
收费全文 | 4962篇 |
免费 | 185篇 |
国内免费 | 797篇 |
专业分类
5944篇 |
出版年
2024年 | 11篇 |
2023年 | 52篇 |
2022年 | 101篇 |
2021年 | 107篇 |
2020年 | 127篇 |
2019年 | 125篇 |
2018年 | 107篇 |
2017年 | 139篇 |
2016年 | 122篇 |
2015年 | 127篇 |
2014年 | 154篇 |
2013年 | 490篇 |
2012年 | 172篇 |
2011年 | 211篇 |
2010年 | 204篇 |
2009年 | 307篇 |
2008年 | 340篇 |
2007年 | 347篇 |
2006年 | 265篇 |
2005年 | 291篇 |
2004年 | 255篇 |
2003年 | 207篇 |
2002年 | 183篇 |
2001年 | 172篇 |
2000年 | 162篇 |
1999年 | 133篇 |
1998年 | 116篇 |
1997年 | 118篇 |
1996年 | 85篇 |
1995年 | 84篇 |
1994年 | 103篇 |
1993年 | 85篇 |
1992年 | 66篇 |
1991年 | 45篇 |
1990年 | 45篇 |
1989年 | 38篇 |
1988年 | 52篇 |
1987年 | 47篇 |
1986年 | 35篇 |
1985年 | 16篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 7篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1972年 | 1篇 |
排序方式: 共有5944条查询结果,搜索用时 0 毫秒
71.
72.
Iwona Wojda 《Insect Science》2017,24(3):342-357
Investigation of insect immune mechanisms provides important information concerning innate immunity, which in many aspects is conserved in animals. This is one of the reasons why insects serve as model organisms to study virulence mechanisms of human pathogens. From the evolutionary point of view, we also learn a lot about host–pathogen interaction and adaptation of organisms to conditions of life. Additionally, insect‐derived antibacterial and antifungal peptides and proteins are considered for their potential to be applied as alternatives to antibiotics. While Drosophila melanogaster is used to study the genetic aspect of insect immunity, Galleria mellonella serves as a good model for biochemical research. Given the size of the insect, it is possible to obtain easily hemolymph and other tissues as a source of many immune‐relevant polypeptides. This review article summarizes our knowledge concerning G. mellonella immunity. The best‐characterized immune‐related proteins and peptides are recalled and their short characteristic is given. Some other proteins identified at the mRNA level are also mentioned. The infectious routes used by Galleria natural pathogens such as Bacillus thuringiensis and Beauveria bassiana are also described in the context of host–pathogen interaction. Finally, the plasticity of G. mellonella immune response influenced by abiotic and biotic factors is described. 相似文献
73.
海洋芽孢杆菌(Bacillus marinus)B-9987菌株抑制病原真菌机理的研究 总被引:3,自引:0,他引:3
摘要:【目的】:探讨海洋芽孢杆菌(Bacillus marinus)B-9987菌株的代谢产物BMME-1,对植物病原真菌茄链格孢菌的抑菌作用机理。【方法】分别使用分光光法、气相色谱-质谱GC-MS联用技术、红外光谱法等,检测了BMME-1处理病原真菌后,菌体渗透性、细胞壁及细胞膜成份的变化。【结果】BMME-1对茄链格孢菌的抑菌中浓度(MIC50)为6.2 mg/L,最小杀菌浓度(MFC)为50 mg/L,在MIC50浓度或高于此浓度处理靶标菌,将导致菌体蛋白质、核酸等大分子物质的外流;处理菌株葡聚糖结 相似文献
74.
75.
76.
Arthur I. Aronson 《FEMS microbiology letters》1986,33(1):47-50
Abstract Conversion of Bacillus subtilis to protoplasts resulted in the release of 70–80% of the total protease inhibitor activity. Inhibitor fractions contained a polypeptide of approx. 15 kDa which reacted with inhibitor antibody. There was no release of protease inhibitor into the medium by sporulating cells, by osmotic shock of cells nor by washing with high concentrations of salt. The release of inhibitor activity was selective in that only 10–20% of the total protein, and < 10% of the glutamine synthetase activity was found in the protoplast supernatant. The inhibitor could be localized near the cell surface and function in cell protection. 相似文献
77.
R. Otto 《FEMS microbiology letters》1986,34(2):191-194
Abstract Gram-negative methylotrophs contain a high- M r 'large' citrate synthase. Gram-positive methylotrophs, on the other hand, contain a 'small' citrate synthase. These differences in M r coincided partly with differences in NADH sensitivity. Citrate synthases from obligate Gram-negative and Gram-positive facultative methylotrophs were insensitive to feedback inhibition by NADH; only the enzymes from Gram-negative facultative methylotrophs were inhibited by NADH. 相似文献
78.
T. de la Rubia J. Gonzalez-Lopez J. Moreno M.V. Martinez-Toledo A. Ramos-Cormenzana 《FEMS microbiology letters》1986,35(1):5-9
Abstract The effect of a low phosphate concentration on intracellular adenine nucleotides, oxygen consumption and poly-β-hydroxybutyric acid synthesis, was investigated with batch cultures of Bacillus megaterium . At low phosphate concentrations the cells contained much larger amounts of poly-β-hydroxybutyric acid, but displayed lower adenylate energy charge and oxygen uptake than did control cells. The ratio of ATP to ADP was much greater in the control cells. The levels of ATP and AMP were lower in low-phosphate cells. 相似文献
79.
The growth strategy of the Gram-positive rod 总被引:3,自引:1,他引:2
Abstract Bacteria grow by enlarging their envelope in such a way that osmotic pressure does not normally cause physical rupture. The strategy of Bacillus subtilis for both cylindrical elongation and pole formation is now substantially defined. Side-wall growth takes place by laying down new peptidoglycan, which is then displaced outwards, stretched and discarded; cross walls are laid down in the absence of stress, and then stretched and bulged outward as the septum is split and the pole is formed. 相似文献
80.
J.M. Rama H. Sandoval M.E. Pons P. Lopez J.F. Martin M. Espinosa 《FEMS microbiology letters》1987,44(3):343-348
Fourteen species of non-pathogenic corynebacteria have been examined for the presence of DNases. Seven of the species were found to be DNase positive when assayed in Toluidine Blue-DNA-containing agar whereas only one, Corynebacterium callunae, could be detectable as DNase positive when the test was performed in DNA-methyl green-containing agar. Electrophoretic patterns obtained from sodium dodecyl sulfate-polyacrylamide gels containing DNA showed the presence of one or two bands of nucleolytic activity in two species of Brevibacterium and of several bands in C. callunae. Degradation of DNases by cellular proteases seem to occur in this species. 相似文献