全文获取类型
收费全文 | 647篇 |
免费 | 7篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 20篇 |
综合类 | 11篇 |
化学工业 | 25篇 |
金属工艺 | 7篇 |
机械仪表 | 4篇 |
建筑科学 | 137篇 |
矿业工程 | 15篇 |
能源动力 | 108篇 |
轻工业 | 52篇 |
水利工程 | 58篇 |
石油天然气 | 14篇 |
武器工业 | 3篇 |
无线电 | 25篇 |
一般工业技术 | 67篇 |
冶金工业 | 50篇 |
原子能技术 | 4篇 |
自动化技术 | 59篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 14篇 |
2018年 | 25篇 |
2017年 | 19篇 |
2016年 | 27篇 |
2015年 | 21篇 |
2014年 | 37篇 |
2013年 | 81篇 |
2012年 | 31篇 |
2011年 | 42篇 |
2010年 | 43篇 |
2009年 | 33篇 |
2008年 | 41篇 |
2007年 | 38篇 |
2006年 | 30篇 |
2005年 | 19篇 |
2004年 | 13篇 |
2003年 | 4篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 8篇 |
1996年 | 5篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1987年 | 2篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1979年 | 3篇 |
1964年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有659条查询结果,搜索用时 31 毫秒
111.
Ahamed S Kumar Sengupta M Mukherjee A Amir Hossain M Das B Nayak B Pal A Chandra Mukherjee S Pati S Nath Dutta R Chatterjee G Mukherjee A Srivastava R Chakraborti D 《The Science of the total environment》2006,370(2-3):310-322
This communication presents results of our 2-year survey on groundwater arsenic contamination in three districts Ballia, Varanasi and Gazipur of Uttar Pradesh (UP) in the upper and middle Ganga plain, India. Analyses of 4,780 tubewell water samples revealed that arsenic concentrations in 46.5% exceeded 10 microg/L, in 26.7%, 50 microg/L and in 10% 300 microg/L limits. Arsenic concentrations up to 3,192 microg//L were observed. The age of tubewells (n=1,881) ranged from less than a year to 32 years, with an average of 6.5 years. Our study shows that older tubewells had a greater chance of contamination. Depth of tubewells (n=3,810) varied from 6 to 60.5 m with a mean of 25.75 m. A detailed study in three administrative units within Ballia district, i.e. block, Gram Panchayet, and village was carried out to assess the magnitude of the contamination. Before our survey the affected villagers were not aware that they were suffering from arsenical toxicity through contaminated drinking water. A preliminary clinical examination in 11 affected villages (10 from Ballia and 1 from Gazipur district) revealed typical arsenical skin lesions ranging from melanosis, keratosis to Bowens (suspected). Out of 989 villagers (691 adults, and 298 children) screened, 137 (19.8%) of the adults and 17 (5.7%) of the children were diagnosed to have typical arsenical skin lesions. Arsenical neuropathy and adverse obstetric outcome were also observed, indicating severity of exposure. The range of arsenic concentrations in hair, nail and urine was 137-10,900, 764-19,700 microg/kg, and 23-4,030 microg/L, respectively. The urine, hair and nail concentrations of arsenic correlated significantly (r=0.76, 0.61, and 0.55, respectively) with drinking water arsenic concentrations. The similarity to previous studies on arsenic contamination in West Bengal, Bihar and Bangladesh indicates that people from a significant part of the surveyed areas in UP are suffering and this will spread unless drives to raise awareness of arsenic toxicity are undertaken and an arsenic safe water supply is immediately introduced. 相似文献
112.
由于资源禀赋的制约,中国钢铁行业存在对进口铁矿石的严重依赖,而铁矿石定价权却被国际钢铁行业寡头掌握,铁矿石的供给已成为中国钢铁行业的发展瓶颈。为解决这一问题,改变中国钢铁行业极其被动的国际地位,促进其稳定发展,故分析了中国钢铁行业投资印度铁矿业的必要性,并通过分析印度铁矿和中国钢铁产业各自具备的优势证实了投资的可行性。 相似文献
113.
The Delta variant is a major SARS-CoV-2 variant of concern first identified in India. To better understand COVID-19 pandemic dynamics and Delta, we use multiple datasets and model-inference to reconstruct COVID-19 pandemic dynamics in India during March 2020–June 2021. We further use the large discrepancy in one- and two-dose vaccination coverage in India (53% versus 23% by end of October 2021) to examine the impact of vaccination and whether prior non-Delta infection can boost vaccine effectiveness (VE). We estimate that Delta escaped immunity in 34.6% (95% CI: 0–64.2%) of individuals with prior wild-type infection and was 57.0% (95% CI: 37.9–75.6%) more infectious than wild-type SARS-CoV-2. Models assuming higher VE among non-Delta infection recoverees, particularly after the first dose, generated more accurate predictions than those assuming no such increases (best-performing VE setting: 90/95% versus 30/67% baseline for the first/second dose). Counterfactual modelling indicates that high vaccination coverage for first vaccine dose in India combined with the boosting of VE among recoverees averted around 60% of infections during July–mid-October 2021. These findings provide support to prioritizing first-dose vaccination in regions with high underlying infection rates, given continued vaccine shortages and new variant emergence. 相似文献
114.
Chetan Pandit 《国际水资源开发杂志》2014,30(1):110-120
India needs large dams for water storage, hydropower and flood control. It also needs long-distance inter-basin water transfers. However, India has a complex and strict environmental regulatory system which ignores a developing economy's needs and peoples' aspirations and is often impractical. This is used by activists to thwart infrastructure building, and, when faced with development slowdown, the government tries to thwart the laws they themselves have made. India's food, water and energy security, economic, and poverty-alleviation plans are in jeopardy unless environmental regulators realize that the regulations are being misused and that environmental over-enthusiasm is benefiting neither development nor the environment. 相似文献
115.
土壤侵蚀导致水土资源流失和生态环境恶化,已成为危及人类生存与发展的重要问题。印度与中国都是世界上水土流失严重的国家,且具有许多相似的自然和社会条件。了解印度土壤侵蚀及其防治的有关研究进展,对促进我国水土保持研究和实践具有现实意义。本文介绍了印度土壤侵蚀的基本状况和特点,并从土壤侵蚀基础研究、土壤侵蚀预报研究和土壤侵蚀防治策略3个方面总结了印度在土壤侵蚀及其防治领域的研究成果和实践经验。在此基础上,提出了对我国土壤侵蚀防治的参考建议。 相似文献
116.
张莹 《导弹与航天运载技术》2012,(3):29-33
随着国际安全环境的重大变化,印度加紧了其军事战略的调整和军队建设的步伐,大力发展导弹武器体系建设,对周边国家和地区形成了安全威胁.在分析印度军事战略的基础上,重点阐述印度弹道导弹、巡航导弹、防空导弹和导弹防御系统等武器装备体系的建设情况,并分析了其发展趋势和未来前景. 相似文献
117.
118.
系统安全背景下未来智能电网建设关键技术发展方向——印度大停电事故深层次原因分析及对中国电力工业的启示 总被引:6,自引:0,他引:6
从外部环境以及内部生产运行中的管理层面和技术层面对本次印度大停电事故的原因进行了深入分析,从管理层面和技术层面分别提出了促进中国电力系统安全稳定运行的基本思路。同时,考虑到电网智能化是未来电网发展的趋势,具有坚强、自愈等特点的智能电网能够有效抵御电网安全风险,提出了基于系统安全的中国未来智能电网建设关键技术发展方向,包括分布式发电并网技术、智能配电技术、智能用电技术和电力系统储能技术,能够为中国下步智能电网发展及电力系统安全稳定运行提供借鉴和参考。 相似文献
119.
2012年7月30日和31日,印度接连发生2次大停电事故,其中第一次事故影响了14个邦,而第二次事故则影响了多达22个邦。此次停电事故波及地区广、涉及人口多,对各国电力发展再次敲响警钟。分析了此次大停电事故的主要原因,结合我国电网发展面临的内外部因素,分析了我国电网发展需要从中汲取的经验教训,并提出相关建议。 相似文献
120.
The major concern in organizations, especially from developing countries, is that there is a huge gap in Intellectual Property (IP) generation and its commercialization. The key issue is that how this gap between IP generation and its commercialization can be reduced. Hence, there is a need to develop an IPM model, which can assist technology and IP managers to develop their own IPMS as well as help in self-assessment of the existing IPMS. This paper introduces an IPM model, which is easy to implement and follow and can be applied to any sector with some modifications. The model suggests 5 stages and 15 major IPM processes. The validation of the model confirmed effortless establishment of IPMS including the identification of potential IP. The IPM model also helped to reveal the gaps, if any, in the current IPMS, and facilitated strategic commercialization of organizational IP. The study followed the case study methodology. 相似文献