共查询到20条相似文献，搜索用时 296 毫秒
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本文从因特网信息检索的概述入手，着重阐述了因特网信息检索的方法及特点，并对因特网信息检索的未来发展趋势做了进一步地探讨。 相似文献
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因特网上灰色文献的开发与利用 总被引：14，自引：0，他引：14
本文分析了因特网上灰色文献的特点 ,介绍了因特网上几个著名的灰色文献信息源 ;就因特网上灰色文献在开发和利用上的问题 ,提出了对策和措施。 相似文献
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因特网信息资源评价研究 总被引：8，自引：1，他引：8
文章论述了因特网信息资源评价的必要性和重要性、评价主体和对象、重点叙述了因特网信息资源评价的指标体系，简要阐述了目前评价因特网信息资源的主要方法。 相似文献
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本文对因特网信息资源组织的实质和内容进行了探讨，提出了由图书馆参与因特网信息组织的基本策略，并针对因特网信息组织的方法、步骤以及应注意的问题作出了作者的看法。 相似文献
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利用因特网信息资源开展竞争情报研究 总被引：4，自引：0，他引：4
因特网是目前国际上信息资源最丰富的网络,它在企业竞争情报研究中得到广泛应用,本文从以下六个方面论述了因特网在企业竞争情报中的应用:(1)强化企业形象,实现国际化经营;(2)有利于企业开拓市场,企业可通过在因特网上建立网页发布商业信息,也可在网上建立电子市场进行商业促销;(3)从因特网上收集竞争对手的商业信息,包括产品样品、销售价格和配置等;(4)利用因特网开发人才资源,如招聘雇员;(5)企业利用因特网开展电子商务;(6)制定企业竞争策略.在此基础上,作者展望了利用因特网开展竞争情报咨询服务的未来. 相似文献
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随着因特网的普及和发展,通过因特网搜集、检索信息已经成为很普遍的现象和行为,而网络信患检索工具更是多种多样.本文概括介绍了因特网信息检索工具的分类特点并进行了分析比较;在此基础上介绍了因特网索引的特点及其标引方法,并就目前网络比较流行的4大搜索引擎进行个案分析研究. 相似文献
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因特网上版权保护的新进展 总被引：12，自引：0，他引：12
因特网的发展大大推进了人类社会信息化的进程，但与此同时，也引发了一系列新的问题，尤其是对传统知识产权制度产生了重大影响。本文主要从因特网上作品版权保护归属、网络传输、复制、网络数据库、版权保护的技术措施以及因特网上版权保护的国际化发展趋势等几个方面，结合 我国现行的著作权法和国际最新发展动态，阐述了因特网的版权保护的新进展。 相似文献
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D. C. Sharma Gora Dadheech Bushra Fiza Meghna Mathur Manminder Riyat Praveen Sharma 《Indian journal of clinical biochemistry : IJCB》2009,24(2):202-204
Silver is ingested in India in the form of varak, Ayurvedic bhasm and water contained in silver utensils, but nobody knows
their effects. We have examined the effect of interaction of silver ingested in the form of varak (leaf), bhasm (ash) and
water (colloidal solution) on some essential elements (Na, K, Ca, Mg, Cu, Fe and Zn) in blood, liver, spleen and kidneys of
chicks. The results showed significant rise of silver in all the tissues and significant fall in copper in the blood. The
greatest rise was obtained in blood silver by silver sol while it had the lowest amount of silver. Iron significantly increased
in tissues but somewhat decreased in blood. Zinc content increased in all the tissues by leaf and ash but decreased by sol.
No consistent pattern was seen in case of other elements. 相似文献
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中国华东及其周边地区NDVI对气温和降水的季节响应 总被引：6，自引：0，他引：6
地表植被与大气的相互作用过程是地球科学领域的研究重点和热点。本文基于SPOTVGT-NDVI数据和气象站点的气温和降水资料,采用时滞相关分析法,研究了1998年-2011年我国华东及其周边地区四季NDVI对气温和降水的时空响应特征。结果表明,在整个研究区,气温对NDVI的影响大于降水,NDVI与气温在夏季和秋季相关性较高,与降水在秋季和春季相关性较高,冬季NDVI与气温和降水相关性都最低。NDVI对气温响应的滞后期在春季和秋季较短,对降水响应的滞后期在冬季较短,夏季NDVI对气温和降水响应的滞后期都较长。在冬季、春季和秋季,NDVI对气温和降水最大相关系数的空间分布在研究区的南北部差异不明显,在夏季则具有较明显的南北差异。NDVI对气温变化响应的滞后期在春季、夏季和秋季具有较明显的南北差异,对降水变化响应的滞后期除在夏季具有一定的南北差异外,在其他季节空间分布规律性不显著。 相似文献
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Elsie L. Echeverri-Carroll Michael D. Oden David V. Gibson Evan A. Johnston 《Research Policy》2018,47(1):209-217
There has been considerable media coverage highlighting the lack of gender diversity in Silicon Valley, stressing the relatively low participation of women in the high-tech economy. Austin offers a unique case for testing whether similar gender issues characterized other high-tech regions because the city has historically benefited from the expansion of Silicon Valley’s large high-tech firms since the 1980s. The gender-biased business practices identified in Silicon Valley firms may have been transferred to their branch plants in Austin. Our analysis shows women’s losses in middle-skill occupation employment shares were concentrated in the low-tech industry and were partially offset by job share gains in high-skill occupations in the same sector between 1980 and 2015. Men’s losses in middle-skill occupation job share were also mainly concentrated in the low-tech sector but were partially offset by employment share gains in high-skill occupations only in the high-tech industry during this period. Women made large gains in relative real median wages only in high-skill occupations in the high-tech industry while their relative real median wages in other skill occupations and in the low-tech industry stagnated around zero during this period. Men’s gains in relative median wages were also concentrated only in the high-tech industry but were less than half of women’s and were negative (between ?10 and ?21 percent) in other occupations in the high-tech industry and across all occupations in the low-tech industry. As noted in previous studies, the impact of job polarization is not well understood across sectors and gender. This study finds the high-tech industry in Austin has had unintended consequences in terms of job polarization across gender, providing relatively fewer job opportunities in high-skill occupations to women than men but offering much higher gains in relative real median wages to women than men. Males also found relatively more job opportunities in high-skill occupations in the high-tech industry than women but experienced only half of women’s gains in relative median wages in this industry between 1980 and 2015. 相似文献
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本文首先介绍电子商务发展中的相关技术,详细分析了电子商务过程中存在的Internet网络和商务活动安全问题。接着给出了一个在电子交易过程中实现电子商务安全的应用系统框架。最后提出了电子商务安全技术发展不足的几个方面,以及发展我国电子商务应该采取的措施。 相似文献
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全球气候变化背景下,由贸易隐含碳失衡导致的"碳泄漏"问题引发了世界各国的普遍关注.本文利用非竞争型投入产出表,构建贸易隐含碳失衡模型,对2000-2011年中日贸易隐含碳失衡规模进行测算.结果显示:①中国各行业完全碳排放系数均高于日本,并且绝大多数行业差距巨大;②总体上,虽然中国处于对日贸易的逆差方,但是在贸易隐含碳方面却一直处于顺差地位,即中国同时处于对日贸易及贸易隐含碳的"双失衡"局面;③从行业来看,中国各行业对日贸易隐含碳均处于失衡状态.其中,纺织业,电气机械/光学设备制造业贸易隐含碳失衡规模最大.在此基础上,采用SDA法建立因素分解模型,对中日贸易隐含碳失衡变化的影响因素进行分析.结果表明,出口规模,中国中间投入结构效应是推动中日贸易隐含碳失衡规模进一步扩大的主要因素,而中国碳排放强度和进口规模效应则主要起到抑制作用.因此,中国应加大推广低碳生产技术力度,降低生产的碳排放强度;同时优化生产以及贸易结构,以缓解中日贸易隐含碳失衡,促进对外贸易及环境保护的协调发展. 相似文献
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论文采用面板数据模型估计了我国制造业集聚的生产率效应,并采用空间俱乐部模型区分了各种效应的地区差别。结果表明,1988-1997年和1998-2009年两个时期,东部和中西部地区均存在显著的静态专业化效应,并且在后期东部的静态专业化效应强于中西部;在整个研究期间,东部和中西部均不存在显著的动态或静态的多样化效应;规模效应在两个时期有所差异,前期在东、中西部均不显著,后期东部存在显著的负向规模效应,而中西部存在正向规模效应,显示出过度集聚开始在东部产生了一定程度的拥塞效应。 相似文献
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The Great Recession, which began in 2008, brought about large contractions in aggregate consumption in many countries. In this research, we study the impact of heterogeneous decreases in demand on innovation investments by analyzing the evolution of innovation investments in a panel of Spanish manufacturing firms during the 2004–2013 period. We proxy heterogeneous variation in demand with net exit rates in the productive stratum of each firm, defined as the group of firms in the same industry and size class. These net exit rates are computed considering all firms in the stratum, including firms that are determined to be non-innovative firms. To support the identification strategy, we show that exit rates do not capture idiosyncratic unobservable characteristics among innovative firms. In addition, we control for the effect of time-varying credit constraints. We find that a one standard deviation increase in exit rates is associated with reductions of 1.5% in the share of firms investing in innovation. The drop is larger for smaller firms, which also experience greater decreases in sales. Since smaller firms are most sensitive to demand drops, they are the natural candidates to be the target of policies devoted to increasing R&D activities during crises. As additional analysis, we study firms’ perceptions of the main obstacles to innovation to find that net exit rates capture the heterogeneous variation in demand, rather than credit constraints. Finally, when analyzing the exit patterns of firms in the sample, we confirm that the net exit rate in a firm's stratum does not drive the exit of firms in our sample. 相似文献
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苏州市与徐州市耕地资源变化与经济发展关系的对比分析 总被引：2，自引：1，他引：1
不同的区域耕地资源变化与经济发展的关系具有明显的差异性。本文采用1978～2006年江苏省苏州市与徐州市的统计数据,分析不同区域中耕地资源变化的特点,并定量分析了耕地资源变化与经济发展的关系,对不同区域GDP增加的耕地占用量进行了对比研究。结果表明:①苏州的耕地面积经历了3次明显的流失高峰,年递减率高达1.34%,而徐州市的耕地面积变化则相对缓和,年递减率只有0.33%,人均耕地面积也有类似的变化趋势;②不同区域的耕地资源面积随着GDP的增加均呈指数递减趋势,用模拟的指数方程对耕地面积的估算值和实际值比较误差较小,证明用指数递减方程预测耕地占用面积随着GDP的变化是可行的;③在不同的区域每单位的GDP增长所消耗的耕地面积随着经济的增加均呈下降趋势,但下降速度不同;④徐州市每增加1×108元所消耗的耕地面积在1978年～1999年,要高于苏州市的水平;在2000年～2006年,则低于苏州市的水平。 相似文献
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Gerard Goggin 《The Information Society》2013,29(3):171-181
In this paper, I approach the question of mobiles in Asian countries by considering the case of Australia. I do so by way of a preliminary inquiry that seeks to explore the intersection between the emergence of mobiles in Australia with transformations in that country's sense of its relationship with Asia. First I discuss the history of the mobile phone in Australia, noting some important uses and representations that formed part of its social shaping. Second, I explore mobiles and the paradoxes of multiculturalism, and also how digital technologies became central to political culture and identity debates in Australia in the early to-mid 1990s. Third, I look at some important moments in the social shaping of text messaging, in which questions of cultural difference were decisive. Finally, I offer concluding remarks about future research on mobiles in Australia and how they are tied into Asian identities. 相似文献
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甘肃省能源经济系统分析与优化策略研究 总被引：2，自引：1，他引：1
能源经济系统的优化不仅是实现区域节能减排目标的重要途径,更是社会经济可持续发展的主要内容,本文以甘肃省为研究案例,基于计量经济学方法,对其经济增长与能源消耗之间的动态关系进行了定量研究;进而运用结构分解模型,对比分析了影响单位GDP能耗的主要因素。研究结果表明:甘肃省GDP与能耗总量之间存在长期的协整关系;促进甘肃省能源强度降低的主要因素是各产业能源利用效率的提高,而产业结构变动对全省能源强度降低的贡献份额较小;对能源强度降低贡献较大的为第二产业的效率份额与结构份额,而第三产业结构份额对能源强度降低的贡献为负。文章最后从产业结构优化、关键技术推进、能源结构优化三个角度提出了甘肃省能源经济系统的优化策略。 相似文献