全文获取类型
收费全文 | 280篇 |
免费 | 2篇 |
国内免费 | 16篇 |
专业分类
系统科学 | 19篇 |
丛书文集 | 8篇 |
教育与普及 | 1篇 |
理论与方法论 | 1篇 |
现状及发展 | 5篇 |
研究方法 | 1篇 |
综合类 | 263篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 11篇 |
2013年 | 34篇 |
2012年 | 73篇 |
2011年 | 40篇 |
2010年 | 26篇 |
2009年 | 59篇 |
2008年 | 13篇 |
2007年 | 3篇 |
2006年 | 1篇 |
2004年 | 3篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1991年 | 2篇 |
排序方式: 共有298条查询结果,搜索用时 15 毫秒
1.
2.
3.
HE Gang~ HUANG Kang~ GUO SongTao~* JI WeiHong~ QI XiaoGuang~ REN Yi~ JIN XueLin~ & LI BaoGuo~ * Key Laboratory of Resource Biology Biotechnology in Western China of Ministry of Education College of Life Sciences Northwest Univer- sity Xi’an China Ecology & Conservation Group Institute for Natural Sciences Massey University Auckl New Zeal Institute of Zoology Shaanxi Academy of Sciences Xi’an Shaanxi Wild Animal Rescue Research Center... 《科学通报(英文版)》2011,56(24):2523-2530
Molecular studies using trace DNA, such as from museum specimens, ancient or forensic samples and samples obtained noninvasively, often have a common problem of low quality of DNA templates. Amplification errors, such as allelic dropout and false allele, may arise during polymerase chain reaction (PCR) using such samples. A mathematical model which treats homozygotes and heterozygotes discriminately has been developed to measure sample quality and compute the confidence level of using multipletube approaches. We use plucked hair samples collected from 26 individual Sichuan snub-nosed monkeys (Rhinopithecus roxel- lana) to test the model. In this case, a confidence level of 99% can be achieved by three positive PCRs. If the sample quality is very poor and requires many PCR replicates, an alternative multiplestep genotyping method is recommended. This model enables researchers to optimize experimental protocols through pilot studies and obtain reliable genetic information using noninvasive sampling method. 相似文献
4.
针对HT2000图形化远动终端交流信号采样模板升级设计的需求,在分析各种交流采样技术的基础上,选用Philips LPC2138作为CPU,ADS8365六通道同时采样系统进行模数转换,并使用锁相环电路获得当前电网频率的倍频信号驱动A/D转换器,实现了交流信号同步采样并完成了该模板的设计.测试和现场运行结果表明,所设计模板的实时性、测量精度和稳定可靠性等关键指标满足相关标准的要求. 相似文献
5.
针对现有HLA仿真资源难以与Internet共享使用的问题,借鉴云计算的思想,采用HLA Evolved相关的技术改进,提出了一种基于HLA Evolved的云仿真的体系结构和框架实现方案;研究了用于Web服务的RTI组件、模块化FOM/SOM对象模型和WSDL API函数等HLA Evolved技术,解决了基于多层语义的服务注册、发现、组合和平台的监控、预测及基于Hadoop的分布式存储、仿真技术;完成了一种战术通信网系统的云仿真测试实验,证明了基于HLA Evolved的云仿真设计方法的可行、有效。 相似文献
6.
为了解决最小误工任务数问题(MTTP),将遗传算法引入该问题的求解中,基于惩罚函数。讨论了MTTP的遗传算法求解方法。并对genGA,ssGA,cGA三种演化式算法求解MTTP的实验运行结果进行分析比较,得出在解决大规模的MTTP时,genGA明显优于另两种演化式算法。 相似文献
7.
8.
HAb18G/CD147-mediated calcium mobilization and hepatoma metastasis require both C-terminal and N-terminal domains 总被引:4,自引:0,他引:4
Jiang JL Chan HC Zhou Q Yu MK Yao XY Lam SY Zhu H Ho LS Leung KM Chen ZN 《Cellular and molecular life sciences : CMLS》2004,61(16):2083-2091
HAb18G/CD147 is a heavily glycosylated protein containing two immunoglobulin superfamily domains. Our previous studies have indicated that overexpression of HAb18G/CD147 enhances metastatic potentials in human hepatoma cells by disrupting the regulation of store-operated Ca2+ entry by nitric oxide (NO)/cGMP. In the present study, we investigated the structure-function of HAb18G/CD147 by transfecting truncated HAb18G/CD147 fragments into human 7721 hepatoma cells. The inhibitory effect of HAb18G/CD147 on 8-bromo-cGMP-regulated thapsigargin-induced Ca2+ entry was reversed by the expression of either C or N terminus truncated HAb18G/CD147 in T7721C and T7721N cells, respectively. The potential effect of HAb18G/CD147 on metastatic potentials, both adhesion and invasion capacities, of hepatoma cells was abolished in T7721C cells, but not affected in T7721N cells. Release and activation of matrix metalloproteinases (MMPs), MMP-2 and MMP-9, were found to be enhanced by the expression of HAb18G/CD147, and this effect was abolished by both truncations. Thapsigargin significantly enhanced release and activation of MMPs (MMP-2 and MMP-9) in non-transfected 7721 cells, and this effect was negatively regulated by SNAP. However, no effects of thapsigargin or SNAP were observed in T7721 cells, and expression of HAb18G/CD147 enhanced secretion and activation of MMPs at a stable and high level. Taken together, these results suggest that both ectodomain and intracellular domains of HAb18G/CD147 are required to mediate the effect of HAb18G/CD147 on the secretion and activation of MMPs and metastasis-related processes in human hepatoma cells by disrupting the regulation of NO/cGMP-sensitive intracellular Ca2+ mobilization although each domain may play different roles.Received 1 April 2004; received after revision 15 June 2004; accepted 22 June 2004 相似文献
9.
10.
目的实现电力企业网上办公,促进信息快速准确的传递。方法基于工作流原理和.NET技术,分析了电力企业标准化办公流程。结果提出了电力企业标准化流程模型。结论实现了电力企业标准化作业系统。 相似文献