全文获取类型
收费全文 | 208篇 |
免费 | 14篇 |
国内免费 | 39篇 |
出版年
2024年 | 4篇 |
2023年 | 10篇 |
2022年 | 20篇 |
2021年 | 33篇 |
2020年 | 16篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 11篇 |
2016年 | 10篇 |
2015年 | 15篇 |
2014年 | 21篇 |
2013年 | 13篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 6篇 |
2009年 | 3篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 2篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
排序方式: 共有261条查询结果,搜索用时 15 毫秒
61.
62.
63.
进化代谢选育高渗透压耐受型产琥珀酸大肠杆菌 总被引:1,自引:0,他引:1
在以碳酸钠为酸中和剂的大肠杆菌两阶段发酵产琥珀酸的过程中,由于Na+的积累造成发酵体系中渗透压的提高,严重抑制了琥珀酸的产物浓度。为了增强大肠杆菌对渗透压的耐受性,考察了利用进化代谢方法筛选高渗透压耐受型高产琥珀酸大肠杆菌菌株的可行性。进化代谢系统作为一种菌株突变装置,可以使菌体在连续培养条件下以最大的生长速率生长。以NaCl为渗透压调节剂,通过在连续培养装置中逐步提高NaCl浓度使菌体在高渗透压条件下快速生长,最终得到了一株高渗透压耐受型琥珀酸生产菌株Escherichia coli XB4。以碳酸钠为酸中和剂,在7 L发酵罐中利用Escherichia coli XB4进行两阶段发酵,厌氧培养60 h后,琥珀酸产量达到了69.5 g/L,琥珀酸生产速率达到了1.81 g/(L.h),分别比出发菌株提高了18.6%和20%。 相似文献
64.
利用花药培养快速创制小麦条锈病和黄矮病抗性新种质 总被引:3,自引:0,他引:3
利用中间偃麦草与普通小麦杂交育成的部分双二倍体-中5为外源抗性基因供体,通过花药培养途径,在它与几个冬小麦品种的5个杂交组合中,诱导出试管花粉绿苗144株,移栽加倍后,形成了49个加倍单倍体株系。通过小麦条锈病和黄矮病抗性鉴定获得了几个高抗黄矮病或者对条锈病近免疫的新材料。其中DH728对条锈病菌近免疫,2n=44,减数分裂构型为0.701V+0.035III+21.579II+0.456I,为双 相似文献
65.
利用生物化学标记分析鉴定一个抗小麦黄矮病的小麦新种质 总被引:8,自引:2,他引:6
利用多个生化标记系统对一个抗小麦黄矮病新种质(HG295)进行了分析鉴定,胚乳水溶蛋白等电聚焦表明,在pH8.0-10.2范围内,中5有3条在其小麦亲本南大2419、克强中匀不存在的克异带,其中只有和经2条在HG295中得到表达。在HG295中,2DS控制的那条水溶蛋白带发生了的缺失,HG295中2DS的缺失在Per-5与Est-6电泳分析中进一步得到确证,Est-7酶谱表明,中5与HG295均表 相似文献
66.
以牙磨耗度和牙指数推算牙齿年龄的多元回归方程式的研究 总被引:3,自引:0,他引:3
本文对97例华南人M~I的磨耗度、牙指数和年龄三者之间的关系进行了深入探讨。并由此而提出以牙磨耗度和牙指数为两个变量的三元回归方程。比较分析结果表明,三元相关系数高于其它二元相关系数,三元回归方程的标准估计误差低于其它二元回归方程的标准估计误差。因而,以三元回归方程式比单纯以牙指数或牙磨耗度作为变量的二元回归方程式估计年龄准确。 相似文献
67.
Network-based protein-protein interaction prediction method maps perturbations of cancer interactome
The perturbations of protein-protein interactions (PPIs) were found to be the main cause of cancer. Previous PPI prediction methods which were trained with non-disease general PPI data were not compatible to map the PPI network in cancer. Therefore, we established a novel cancer specific PPI prediction method dubbed NECARE, which was based on relational graph convolutional network (R-GCN) with knowledge-based features. It achieved the best performance with a Matthews correlation coefficient (MCC) = 0.84±0.03 and an F1 = 91±2% compared with other methods. With NECARE, we mapped the cancer interactome atlas and revealed that the perturbations of PPIs were enriched on 1362 genes, which were named cancer hub genes. Those genes were found to over-represent with mutations occurring at protein-macromolecules binding interfaces. Furthermore, over 56% of cancer treatment-related genes belonged to hub genes and they were significantly related to the prognosis of 32 types of cancers. Finally, by coimmunoprecipitation, we confirmed that the NECARE prediction method was highly reliable with a 90% accuracy. Overall, we provided the novel network-based cancer protein-protein interaction prediction method and mapped the perturbation of cancer interactome. NECARE is available at: https://github.com/JiajunQiu/NECARE. 相似文献
68.
DNA甲基化在动物组织发育和分化等生物过程中发挥至关重要的作用.本研究采用荧光标记甲基化敏感扩增多态性(fluorescence-labeled methylation sensitive amplified polymorphism,F-MSAP)技术分析了中华菊头蝠(Rhinolophus sinicus)脑、心、... 相似文献
69.
70.
Jiajun Yan Jianbo Zhang Kaiyan Sun Dan Chang Shiqie Bai Yixin Shen Linkai Huang Jin Zhang Yu Zhang Yanhai Dong 《PloS one》2016,11(3)
Erianthus arundinaceus is not only an important germplasm resource for sugarcane breeding but also a potential bioenergy plant. Making clear the distribution of the chromosome ploidy of wild E. arundinaceus in china is the premise of the research and utilization of this species. Therefore, the objectives of this study were to determine the ploidy level and DNA content of the 55 E. arundinaceus accessions using flow cytometry and to identify the correlation between ploidy and phenotypic traits. Among the 55 accessions, four tetraploids and 51 hexaploids were identified. The four tetraploids originated from Mengma Yunnan, Shuangjiang Yunnan, Gaozhou Guangdong and Chengle Sichuan. The mean DNA content was 4.82 pg/2C for the tetraploid and 7.30 pg/2C for the hexaploid plants. The ploidy was negatively correlated with cellulose content and positively correlated (P<0.05) with plant height, stem diameter, leaf width, dry weight per plant, fresh weight per plant and hemicellulose content. However, ploidy was not correlated with leaf length, tiller number and the ratio of dry weight and fresh weight. This study will be useful for revealing the distribution of the ploidy of wild E. arundinaceus in Chin, traits markers analysis, and utilization of this species, such as cultivar improvement and sugarcane breeding in the future. 相似文献