全文获取类型
收费全文 | 2813篇 |
免费 | 100篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 18篇 |
综合类 | 1篇 |
化学工业 | 842篇 |
金属工艺 | 42篇 |
机械仪表 | 61篇 |
建筑科学 | 37篇 |
矿业工程 | 3篇 |
能源动力 | 229篇 |
轻工业 | 209篇 |
水利工程 | 12篇 |
石油天然气 | 7篇 |
无线电 | 268篇 |
一般工业技术 | 505篇 |
冶金工业 | 178篇 |
原子能技术 | 23篇 |
自动化技术 | 488篇 |
出版年
2023年 | 39篇 |
2022年 | 103篇 |
2021年 | 124篇 |
2020年 | 99篇 |
2019年 | 104篇 |
2018年 | 119篇 |
2017年 | 95篇 |
2016年 | 73篇 |
2015年 | 62篇 |
2014年 | 105篇 |
2013年 | 340篇 |
2012年 | 105篇 |
2011年 | 99篇 |
2010年 | 104篇 |
2009年 | 101篇 |
2008年 | 97篇 |
2007年 | 99篇 |
2006年 | 91篇 |
2005年 | 70篇 |
2004年 | 39篇 |
2003年 | 43篇 |
2002年 | 37篇 |
2001年 | 29篇 |
2000年 | 31篇 |
1999年 | 39篇 |
1998年 | 62篇 |
1997年 | 47篇 |
1996年 | 43篇 |
1995年 | 40篇 |
1994年 | 39篇 |
1993年 | 29篇 |
1992年 | 34篇 |
1991年 | 27篇 |
1990年 | 22篇 |
1989年 | 34篇 |
1988年 | 27篇 |
1987年 | 16篇 |
1986年 | 18篇 |
1985年 | 45篇 |
1984年 | 23篇 |
1983年 | 31篇 |
1982年 | 25篇 |
1981年 | 19篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1975年 | 9篇 |
1971年 | 6篇 |
排序方式: 共有2923条查询结果,搜索用时 15 毫秒
91.
Kar Nikunja Bihari Babu Korra Sathya Sangaiah Arun Kumar Bakshi Sambit 《Multimedia Tools and Applications》2019,78(4):4789-4812
Multimedia Tools and Applications - This paper discusses the development of an efficient and automated system for the recognition of facial expressions, which is essentially an application... 相似文献
92.
Abhinav Sharma Yashodhan Patil Ravi Krishnaiah PhD B. Ashok PhD Akhil Garg PhD Liang Gao PhD 《亚洲传热研究》2020,49(8):4626-4656
Lithium-ion cells are preferred in the electrical powertrain due to high-power density, compactness, and modularity. In real driving conditions, the cells undergo discharge rates as high as 4 C resulting in high heat generation affecting the performance. To obtain the maximum performance the pack construction and thermal management of cells are crucial parameters. In our work, air-cooled technique with diverse air inlet and staggered scheme with a two-channel partition approach for thermal management of the cylindrical lithium-ion cells are studied in computational fluid dynamics. The simulation model is validated with experimental results. The obtained results demonstrate that the cells in the dual-directional air inlet arrangement had low maximum temperature difference among and within the cells and required least fan work. This arrangement required least fan work to generate optimal air inlet velocity of 2 m/s for 1, 2, and 3 C and 4 m/s for 4 C discharge rates. There is a reduction of 50% and 33% fan work for 3 and 4 C discharge rates, which are the majority operating points. Also, it shows that the temperature uniformity within the cells has improved. The results of this study can used to optimize parameters for designing an enhanced thermal management system. 相似文献
93.
Geoffrey Lawrence Arun V Baskar Mohammed H El-Newehy Wang Soo Cha Salem S Al-Deyab Ajayan Vinu 《Science and Technology of Advanced Materials》2015,16(2)
Three-dimensional cage-like mesoporous FDU-12 materials with large tuneable pore sizes ranging from 9.9 to 15.6 nm were prepared by varying the synthesis temperature from 100 to 200 °C for the aging time of just 2 h using a tri-block copolymer F-127(EO106PO70EO106) as the surfactant and 1,3,5-trimethyl benzene as the swelling agent in an acidic condition. The mesoporous structure and textural features of FDU-12-HX (where H denotes the hydrothermal method and X denotes the synthesis temperature) samples were elucidated and probed using x-ray diffraction, N2 adsorption, 29Si magic angle spinning nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy. It has been demonstrated that the aging time can be significantly reduced from 72 to 2 h without affecting the structural order of the FDU-12 materials with a simple adjustment of the synthesis temperature from 100 to 200 °C. Among the materials prepared, the samples prepared at 200 °C had the highest pore volume and the largest pore diameter. Lysozyme adsorption experiments were conducted over FDU-12 samples prepared at different temperatures in order to understand their biomolecule adsorption capacity, where the FDU-12-HX samples displayed high adsorption performance of 29 μmol g−1 in spite of shortening the actual synthesis time from 72 to 2 h. Further, the influence of surface area, pore volume and pore diameter on the adsorption capacity of FDU-12-HX samples has been investigated and results are discussed in correlation with the textural parameters of the FDU-12-HX and other mesoporous adsorbents including SBA-15, MCM-41, KIT-5, KIT-6 and CMK-3. 相似文献
94.
Swati Garg Marlene J. Cran Vijay Kumar Mishra 《International Journal of Food Science & Technology》2019,54(5):1892-1900
The effects of different pH treatments with and without heating on the characteristics of wheat gluten suspension was investigated. At pH 1, maximum changes in colour were observed with a concurrent 65% decrease in protein free-thiol content compared to the control gluten. The SDS-Extractability of protein (SDS-EP) chromatogram eluted at lower retention time and the presence of bands at the top lane even during reducing conditions in SDS-PAGE gel suggested complex formation involving bonds other than disulphides. An increase in the free-amino group content and the presence of an additional peak at a higher retention time in the SDS-EP chromatogram was suggestive of hydrolysis. At pH 2 and 3, similar decreases in SDS-EPs and free-thiol content indicated formation of complexes. When heated, the free-thiol content of the dispersions increased compared to the non-heated dispersions indicating disruption of disulphide bonds with changes in gluten structure and size distribution. 相似文献
95.
Claire Fortenberry Michael Walker Audrey Dang Arun Loka Gauri Date Karolina Cysneiros de Carvalho Glenn Morrison Brent Williams 《Indoor air》2019,29(5):761-779
The air composition and reactivity from outdoor and indoor mixing field campaign was conducted to investigate the impacts of natural ventilation (ie, window opening and closing) on indoor air quality. In this study, a thermal desorption aerosol gas chromatograph (TAG) obtained measurements of indoor particle‐ and gas‐phase semi‐ and intermediately volatile organic compounds both inside and outside a single‐family test home. Together with measurements from a suite of instruments, we use TAG data to evaluate changes in indoor particles and gases at three natural ventilation periods. Positive matrix factorization was performed on TAG and adsorbent tube data to explore five distinct chemical and physical processes occurring in the indoor environment. Outdoor‐to‐indoor transport is observed for sulfate, isoprene epoxydiols, polycyclic aromatic hydrocarbons, and heavy alkanes. Dilution of indoor species is observed for volatile, non‐reactive species including methylcyclohexane and decamethylcyclopentasiloxane. Window opening drives enhanced emissions of semi‐ and intermediately volatile species including TXIB, DEET, diethyl phthalate, and carvone from indoor surfaces. Formation via enhanced oxidation was observed for nonanal and 2‐decanone when outdoor oxidants entered the home. Finally, oxidative depletion of gas‐phase terpenes (eg, limonene and α‐pinene) was anticipated but not observed due to limited measurement resolution and dynamically changing conditions. 相似文献
96.
97.
Microsystem Technologies - The recent availability of inexpensive digital recording and storage devices have created an environment to obtain, replicate and distribute digital content without any... 相似文献
98.
Vishal Garg Akshey Jawa Jyotirmay Mathur Aviruch Bhatia 《Journal of Building Performance Simulation》2014,7(3):179-191
This paper describes how the EPparallel tool splits a single annual simulation into 12 simulations of one month each and runs them in parallel. The paper also describes the methodology to prepare input files, enable file sharing between nodes, collate results generated by the nodes, and ensure quality check on the simulations. The EPparallel tool uses Message Passing Interface library and runs on Linux. The tool has been tested on 16 commercial reference buildings over 16 US weather files. The results of these 256 runs which include the run times, computing time overheads, speed gains and accuracy of results are presented in this paper. The speed gain ranged from 2.9×to 7.8×and deviation (percentage of output values obtained in parallel simulation which were off by more than 1% as compared to output values obtained in annual simulation) ranged from 0% to 4%. 相似文献
99.
Anuj Kumar K. V. Sharma Arun Gupta Jan Tywoniak Petr Hajek 《Holz als Roh- und Werkstoff》2017,75(2):203-213
In the present work, medium density fiberboard (MDF) panels were produced using multiwalled carbon nanotubes (MWCNT) reinforced urea formaldehyde resin. Response surface methodology was employed to optimize the relationship between the three variables, viz. pressing time, percentage of UF resin and percentage of MWCNT, used in the fabrication of MDF, and the influence of variables on the internal bonding (IB) and modulus of rupture (MOR) was studied. The optimum conditions based on the IB strength were determined as 8.18 % of UF resin, pressing time of 232 s, and MWCNT of 3.5 %. Similarly, the optimized conditions for MOR are also reported in this paper. 相似文献
100.
Srinivasan Arjun Tekalur Arun Shukla Martin Sadd K. Wayne Lee 《Construction and Building Materials》2009,23(5):1795-1802
There are various methods to determine the compressive and tensile strength of asphalt concrete under static loading conditions and most studies on asphalt strength and fracture have been conducted under such loading conditions. However, pavement materials also have to withstand a wide variety of loading and temperature conditions which may vary from quasi-static to high-strain rate impact, and pavement breakdown may occur due to fracture and/or fatigue failure. In the present study, a bituminous mix with 30% RAP has been characterized under quasi-static (10?3–10?4 strain/s) and high-strain rate (200–700 strain/s) regimes. The experimental studies have been performed to better understand the compressive, tensile and fracture response of bituminous mixes. Split Hopkinson pressure bar (SHPB) and its modifications were used for high-strain rate characterization of this bituminous mixture. It was observed that the mechanical properties of the hot mix asphalt (HMA) changed significantly under high-strain rate testing. Also, the failure mechanisms observed under the high-strain rate loading were found to be considerably different from those obtained in static testing, where failure of binder was a predominant mechanism. It was observed that high-strain rate loading caused trans-aggregate failures in the specimens; in addition to failure of the binder. 相似文献