全文获取类型
收费全文 | 793篇 |
免费 | 25篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 108篇 |
金属工艺 | 22篇 |
机械仪表 | 18篇 |
建筑科学 | 9篇 |
矿业工程 | 1篇 |
能源动力 | 28篇 |
轻工业 | 41篇 |
石油天然气 | 1篇 |
无线电 | 111篇 |
一般工业技术 | 190篇 |
冶金工业 | 99篇 |
原子能技术 | 3篇 |
自动化技术 | 188篇 |
出版年
2023年 | 9篇 |
2022年 | 19篇 |
2021年 | 20篇 |
2020年 | 13篇 |
2019年 | 13篇 |
2018年 | 18篇 |
2017年 | 19篇 |
2016年 | 21篇 |
2015年 | 12篇 |
2014年 | 33篇 |
2013年 | 51篇 |
2012年 | 40篇 |
2011年 | 44篇 |
2010年 | 35篇 |
2009年 | 27篇 |
2008年 | 39篇 |
2007年 | 32篇 |
2006年 | 18篇 |
2005年 | 20篇 |
2004年 | 9篇 |
2003年 | 36篇 |
2002年 | 23篇 |
2001年 | 19篇 |
2000年 | 15篇 |
1999年 | 19篇 |
1998年 | 31篇 |
1997年 | 21篇 |
1996年 | 20篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 14篇 |
1992年 | 13篇 |
1991年 | 8篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有828条查询结果,搜索用时 281 毫秒
1.
Marcos Antônio Klunk Nattan Roberto Caetano Rommulo Vieira Conceição Paulo Roberto Wander Sudipta Dasgupta 《The International journal of environmental studies》2020,77(3):492-509
ABSTRACT Several Carbon Capture and Storage (CCS) techniques have been studied including injections of carbon dioxide (CO2) into the mature and/or depleted hydrocarbon reservoirs and deep saline aquifers. This work aims to test storing CO2 into the magnesium-rich evaporite strata and also into the stratigraphic intervals containing Mg-rich brines. The test simulates Mg-carbonation of the synthetic solution obtained from the Mg-evaporite mineral, bischofite – both experimentally in the laboratory condition and also through computerised geochemical simulation. The laboratory experiments, which resulted in the crystallisation of anhydrous magnesite, were analysed. The TOUGHREACTTM, Geochemist’s WorkbenchTM (GWB) and PHREEQCTM software simulated the experiments as computerised geochemical model and tested the results for natural geological conditions. The geochemical simulations successfully demonstrate the immense CCS potential for the Mg-evaporite (as well as the sedimentary strata charged with Mg-evaporitic brine) at their subsurface geological occurrences at elevated pressure-temperature and high salinity. 相似文献
2.
3.
Utilities typically depend on customers to call and inform them of the service interruptions due to outages by entering their addresses. After sufficient calls are received, the utility is able to pinpoint the location of outages. It is essential for the utility to have a good idea on the location of outages before sending crew for restoration work to optimally utilize their resources. This article uses an idiotypic immune system to model and simulate radial distribution system to identify the operated protective devices due to outages. The incoming calls are modeled as antigens, and the protective devices are modeled as antibodies. Using a differential equation describing dynamics of the immune system, the operated protective devices in the network are identified. A pre-processing technique is presented to handle cases with multiple outages within the same period. Different threshold values for call grouping are tested to determine the most suitable values. Several real-life examples are considered to demonstrate that the proposed method is able to identify the correct protective devices. 相似文献
4.
In water-cooled nuclear reactors, the maximum power which can be extracted from the core is limited by critical heat flux (CHF). CHF in the high-quality region is known as dryout. In advanced nuclear reactors, the coolant flow occurs solely by virtue of natural circulation; however, instabilities may occur during off-normal operations. This may lead to premature dryout due to lower coolant flow rates seen by the heater during such oscillations. This paper describes the experimental investigation on the effect of flow oscillations on the CHF with the time period of 120 s, which is observed typically in the large-scale natural circulation system. Based on observations made with respect to temperature transient, the continuous dryout is preceded by the transient dryout for higher flow oscillations. But as flow fluctuation decreases, the transient dryout phenomenon is found to disappear. The applicability of the look-up table to predict CHF under oscillatory flow conditions using suitable correction factors (CFs) for premature dryout has been evaluated. CFs for the CHF under oscillations suggested by previous authors have been compared. The maximum possible degradation in CHF value suggested by previous authors has been found to agree with the present experimental data. Percentage fluctuation in heat transfer coefficient (HTC) at fully developed annular flow conditions has been evaluated, and it is found that fluctuation in HTC is in phase with the fluctuation in flow. 相似文献
5.
Debnath Sanjoy Arif Wasim Roy Sourav Baishya Srimanta Sen Debarati 《Wireless Personal Communications》2022,124(2):1375-1421
Wireless Personal Communications - The performance of wireless communication network is important in emergency rescue operations while ensuring optimum usage of limited wireless resources. Due to... 相似文献
6.
Jiani Wang Jiangtao Li Shamik Dasgupta Li Zhang Mikhail Y. Golovko Svetlana A. Golovko Jiasong Fang 《Lipids》2014,49(4):347-356
Pressure is an important thermodynamic property of the ocean and the deep biosphere that affects microbial physiology and biochemistry. Here, we report on our investigation of the response of Gram-positive piezotolerant bacterium Sporosarcina sp. DSK25 to hydrostatic pressure. Strain DSK25 responded in an adaptive manner to upshifts of growth pressure and showed systematic changes in phospholipid fatty acids. As the pressure increased from 0.1 to 10 MPa (Megapascal), unsaturated fatty acids in DSK25 increased from 21.7 to 31.1 % of total fatty acids, while the level of iso- and anteiso-branched fatty acids remained unchanged. At higher pressures (30, 50, and 60 MPa), the amount of unsaturated fatty acids decreased, and that of anteiso-branched fatty acids increased from 34.4 to 49.9 % at the expense of iso-branched fatty acids. For the first time, two polyunsaturated fatty acids (PUFA), 18:2n-6 and 18:2n-x, with the latter having much higher abundance than the former, were identified in DSK25. The concentration of the PUFA increased with growth pressure. These results indicate the involvement of unsaturated and methyl-branched fatty acids in the modulation of bacteria membrane fluidity and function over environmentally relevant parameter (pressure). Piezotolerant bacterium Sporosarcina sp. DSK25 appears to utilize two regulatory mechanisms for adaptation to high pressure, a rapid-responding mechanism on transient scale, expressed as increased biosynthesis of monounsaturated fatty acids, and a long-term adaptation mechanism in increased synthesis of anteiso-branched and polyunsaturated fatty acids. Our results further suggest that Gram-positive piezophilic bacteria respond differently than Gram-negative bacteria in adaptation to high pressure. 相似文献
7.
8.
9.
Das Sayan Roy Nilanjana Dutta Biswas Arindam Saha Sanjoy Kumar 《Multimedia Tools and Applications》2021,80(3):4093-4110
Multimedia Tools and Applications - Vessel extraction from the retinal fundus images plays a significant role in ophthalmologic disease diagnosis. Proliferative Diabetic Retinopathy (PDR) is the... 相似文献
10.
Das Madhu Sudan Samanta Anu Sanyal Sourish Mandal Sanjoy 《Wireless Personal Communications》2021,120(4):3389-3413
Wireless Personal Communications - Mobile robot navigation has been a current issue in the most recent two decades. Mobile robots are necessary to explore in obscure and dynamic situations. To... 相似文献