全文获取类型
收费全文 | 217篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
林业 | 4篇 |
农学 | 5篇 |
基础科学 | 1篇 |
64篇 | |
综合类 | 27篇 |
农作物 | 16篇 |
水产渔业 | 12篇 |
畜牧兽医 | 85篇 |
园艺 | 1篇 |
植物保护 | 14篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 7篇 |
2017年 | 3篇 |
2016年 | 8篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 14篇 |
2012年 | 16篇 |
2011年 | 22篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 7篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 8篇 |
2004年 | 12篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1969年 | 2篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1945年 | 1篇 |
排序方式: 共有229条查询结果,搜索用时 15 毫秒
61.
Chu CY Lee MJ Liao CL Lin WL Yin YF Tseng TH 《Journal of agricultural and food chemistry》2003,51(26):7583-7588
The dried fruit of Crataegus pinnatifida, a local soft drink material and medical herb, was found to possess potential against oxidative stress. In the preliminary study, the antioxidant potential of a hot-water extract obtained from the dried fruit of C. pinnatifida (CF-H) was evaluated in terms of its capacity of quenching 1,1-diphenyl-2-picrylhydrazyl free radicals (EC(50) = 0.118 mg/mL). After content analysis, it was found that CF-H is mainly composed of polyphenols including flavonoids (6.9%), procyanidins (2.2%), (+)-catechin (0.5%), and (-)-epicatechin (0.2%). The antioxidative bioactivity of CF-H had been assess previously using the models of CuSO(4) as cell-free system and sodium nitroprusside (SNP) plus macrophage RAW 264.7 cells as cell system to induce human low-density lipoprotein oxidation. CF-H was found to inhibit relative electrophoretic mobility and thiobarbituric acid reactive substances at the concentration of 0.5-1.0 mg/mL in the cell-free system and at 0.01-0.10 mg/mL in the cell system. Furthermore, it was found that CF-H decreased the SNP-induced cell lipid peroxidation and reduced glutathione depletion. 相似文献
62.
63.
64.
1986-1988年在田间小区经人工接种,观察比较了小麦条锈病、叶锈病和白粉病单独及混合发生时的流行过程。结果经统计分析表明,在病害混生初期、病情较轻时,病害间没有明显的负相关性,随着病情的加重,病害间的负相关性逐渐增强,表现出明显的相互抑制现象。将不同病害的病情指数经重叠侵染公式转换后进一步分析证明,病害间在高病指下表现的抑制作用除病害间的重叠侵染外,还有拮抗作用存在。该文还对研究多种病虫害相互关系的方法进行了讨论。 相似文献
65.
Bernardette Primieri Carelli Lee Tseng Sheng Gerald Felipe Gobbi Grazziotin Sergio Echeverrigaray 《Genetic Resources and Crop Evolution》2006,53(2):395-400
Random amplified polymorphic DNA markers (RAPD) were used to estimate the variability of 35 tomato accessions (Lycopersicon esculentum Mill.). A total of 257 reproducibly scorable bands were obtained from 20 primers, 78.6% of which were polymorphic. The percentage
distribution of RAPD markers shows a bimodal distribution, and the frequency of rare alleles is similar in commercial and
landrace accessions. Genetic distances among accessions were calculated and a dendrogram showing the genetic relationships
among them was constructed allowing for the separation of four groups. Twenty out of 23 Brazilian landraces fell within one
group, whereas commercial cultivars were distributed in the four groups. AMOVA analysis of RAPD data showed that, despite
the high within Brazilian landraces and commercial cultivars variation, these two groups are significantly different, indicating
that landraces can be a source of variation for breeding programs. 相似文献
66.
67.
68.
Chang CC Chen YJ Tseng CS Lai WL Hsu KY Chang CL Lu CC Hsu YM 《Veterinary microbiology》2011,149(1-2):147-156
Bartonella henselae can cause a wide range of clinical outcomes and may lead to severe disease, especially in patients with acquired immunodeficiency syndrome. It is well-known that B. henselae-induced cell proliferation is mediated by anti-apoptotic activity; however, the detailed mechanism is still unclear. In this study, the cellular responses of endothelial cells after infection with four B. henselae strains were compared and protein candidates that may be involved in the interaction between cells and bacteria were determined. The Houston-1 strain elicited the fastest response in terms of stimulating endothelial cell proliferation, and the JK-40 strain had the strongest ability to induce cell proliferation. By Western blot analysis, it was demonstrated that B. henselae-induced cell proliferation involved the mitochondria intrinsic apoptotic pathway. In addition, the adhesion abilities of the U-4 and JK-40 strains were much greater than those of the Houston-1 and JK-47 strains; however, the ability of Houston-1 to invade host cells was high. By two-dimensional gel electrophoresis analysis, it was found that succinyl-CoA synthetase subunit beta, phage-related protein, and ATP synthase subunit alpha might be involved in the invasion process. The expression of superoxide dismutase [Cu-Zn] precursor increased with infection time for all four strains but was significantly higher in the Houston-1 strain, which may increase the competitive advantage of Houston-1 in terms of survival in host cells and render it successful in invading host cells and stimulating cell proliferation. Our data suggest that the interaction of B. henselae and endothelial cells differed between strains, and the results indicated possible candidate proteins that may play a role in the pathogenesis of B. henselae infection. 相似文献
69.
L-Rhamnose isomerase (EC 5.3.1.14, l-RhI) catalyzes the reversible aldose-ketose isomerization between L-rhamnose and L-rhamnulose. In this study, the L-rhi gene encoding L-RhI was PCR-cloned from Caldicellulosiruptor saccharolyticus ATCC 43494 and then expressed in Escherichia coli. A high yield of active L-RhI, 3010 U/g of wet cells, was obtained after 20 °C induction for 20 h. The enzyme was purified sequentially using heat treatment, nucleic acid precipitation, and ion-exchange chromatography. The purified L-RhI showed an apparent optimal pH of 7 and an optimal temperature at 90 °C. The enzyme was stable at pH values ranging from 4 to 11 and retained >90% activity after a 6 h incubation at 80 °C and pH 7-8. Compared with other previously characterized L-RhIs, the L-RhI from C. saccharolyticus ATCC 43494 has a good thermostability, the widest pH-stable range, and the highest catalytic efficiencies (k(cat)/K(M)) against L-rhamnose, L-lyxose, L-mannose, D-allose, and D-ribose, suggesting that this enzyme has the potential to be applied in rare sugar production. 相似文献
70.