全文获取类型
收费全文 | 1168篇 |
免费 | 40篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 9篇 |
综合类 | 2篇 |
化学工业 | 288篇 |
金属工艺 | 34篇 |
机械仪表 | 26篇 |
建筑科学 | 33篇 |
矿业工程 | 2篇 |
能源动力 | 72篇 |
轻工业 | 90篇 |
水利工程 | 2篇 |
石油天然气 | 16篇 |
无线电 | 88篇 |
一般工业技术 | 312篇 |
冶金工业 | 57篇 |
原子能技术 | 15篇 |
自动化技术 | 164篇 |
出版年
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 56篇 |
2021年 | 61篇 |
2020年 | 44篇 |
2019年 | 35篇 |
2018年 | 63篇 |
2017年 | 52篇 |
2016年 | 42篇 |
2015年 | 30篇 |
2014年 | 49篇 |
2013年 | 102篇 |
2012年 | 49篇 |
2011年 | 77篇 |
2010年 | 66篇 |
2009年 | 61篇 |
2008年 | 58篇 |
2007年 | 49篇 |
2006年 | 42篇 |
2005年 | 37篇 |
2004年 | 27篇 |
2003年 | 20篇 |
2002年 | 13篇 |
2001年 | 17篇 |
2000年 | 6篇 |
1999年 | 10篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 7篇 |
1995年 | 11篇 |
1994年 | 5篇 |
1993年 | 13篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 8篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1975年 | 1篇 |
排序方式: 共有1210条查询结果,搜索用时 15 毫秒
21.
Some of the classical connectivity concepts in Graph theory are generalized in this article. Strong and strongest strong cycles are introduced. Partial blocks are characterized using strongest paths. Some necessary and sufficient conditions for a weighted graph to be a partial block are also presented. 相似文献
22.
23.
Arun Kumar K V Revathy K P Prathibha Vasudevan Sunil Thomas Biju P R Unnikrishnan N V 《中国稀土学报(英文版)》2013,31(5):441-448
We reported here the structural and optical characterisation of silver nanocrystallites/Eu3+ :SiO2-TiO2 matrices synthesised through sol-gel route. Structural characterisations were done by using energy dispersive spectroscopy (EDX), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), atomic force microscope (AFM) and transmission electron microscopy (TEM) measurements and optical characterisations were performed by absorption and emission spectroscopy. The TEM and XRD measurements confirmed the presence of nanocrystals. A broad absorption band was observed due to surface plasmon resonance of silver nanocrystals. The effect of silver nanocrystals on the emission spectrum of Eu3+ doped SiO2-TiO2 matrices was discussed. An attempt was made to explain this fluorescence enhancement by invoking phenomena such as energy transfer, asymmetry ratio, surface plasmon, surface roughness, crystallinity and grain boundary. Our analysis, based on the experimental results, suggested that all the phenomena except crystallinity and grain boundary had favourable effects on fluorescence enhancement. We also estimated the relevant parameters associated with the phenomena that affected the fluorescence emission from the Eu3+ ions in the matrix. It was seen that the theoretical estimate of fluorescence enhancement agreed well with the experimental estimate. 相似文献
24.
The Cr:Fe ratio (chromium-to-iron mass ratio) of chromite affects the production of chrome-based ferroalloys. Although the lit-erature contains numerous reports related to the magnetic separation of di... 相似文献
25.
This paper addresses the rail transportation of food grains undertaken by Food Corporation of India (FCI) to meet the requirements of the food security programme called Public Distribution System (PDS). The research focuses on improving the allocation of railway rakes transporting food grains to a set of storage warehouses. A penalty factor based approach is adopted to represent the considerations in transportation planning and three penalty factors such as rake penalty factor, weekly penalty factor and capacity utilization penalty factor are introduced for the purpose. The single source - multiple destination problem is formulated and solved using exact method to minimize the sum of these three penalty factor values, termed total penalty. Further, a heuristic named optimum rake allocation algorithm is developed and tested using a set of 35 problem instances. The proposed heuristic is found to be highly efficient in terms of solution quality and computation time. A case study of FCI Kerala Region is also carried out to validate the formulated model and the proposed heuristic. The work provides valuable insights into the practical issues encountered in rail freight transportation planning and proposes an effective solution methodology to address them. 相似文献
26.
Sunil Kumar Gupta Dinh Phung Brett Adams Svetha Venkatesh 《Data mining and knowledge discovery》2013,26(1):57-97
Joint modeling of related data sources has the potential to improve various data mining tasks such as transfer learning, multitask clustering, information retrieval etc. However, diversity among various data sources might outweigh the advantages of the joint modeling, and thus may result in performance degradations. To this end, we propose a regularized shared subspace learning framework, which can exploit the mutual strengths of related data sources while being immune to the effects of the variabilities of each source. This is achieved by further imposing a mutual orthogonality constraint on the constituent subspaces which segregates the common patterns from the source specific patterns, and thus, avoids performance degradations. Our approach is rooted in nonnegative matrix factorization and extends it further to enable joint analysis of related data sources. Experiments performed using three real world data sets for both retrieval and clustering applications demonstrate the benefits of regularization and validate the effectiveness of the model. Our proposed solution provides a formal framework appropriate for jointly analyzing related data sources and therefore, it is applicable to a wider context in data mining. 相似文献
27.
Sunil Pandey Ritu Shah Ashmi Mewada Mukeshchand Thakur Goldie Oza Madhuri Sharon 《Journal of materials science. Materials in medicine》2013,24(7):1671-1681
Use of cysteamine hydrochloride (Cys-HCl) protected gold nanorods (GNRs) as efficient carrier of widely used anti-cancer drug doxorubicin using folic acid as navigational molecule is presented in this work. GNRs were found to have excellent drug loading capacity of >97 %. A detailed comprehension of in vitro drug release profile under ideal physiological condition was found to obey 1st order kinetics at pH 6.8, 5.3 and 7.2, an ideal milieu for drug delivery to solid tumours. 相似文献
28.
29.
V. Shiva Sunil Goyal R. Sandhya K. Laha A. K. Bhaduri 《Transactions of the Indian Institute of Metals》2017,70(3):589-596
In this investigation, the flow behaviour of modified 9Cr–1Mo steel at elevated temperatures is reported. To understand the flow behaviour of the steel, tensile tests were performed at nominal strain rate of 3 × 10?3 s?1 and temperatures in the range of 300–823 K. The yield strength and ultimate tensile strength were found to decrease with increase in temperature with a plateau in a intermediate temperature regime (523–673 K). Serrations were also observed in the tensile curve at intermediate temperatures which caused plateau/peak in tensile behaviour of material and was a typical manifestation of dynamic strain ageing. An attempt was made to represent the flow behaviour of the material using different constitutive equations viz., Hollomon, Ludwik, Swift, Ludwigson and Voce. It was observed that the Voce equation could describe the experimental flow curve at different temperatures quite well. Instantaneous work hardening rate with respect to flow stress exhibited two stages of hardening especially at relatively lower temperatures. 相似文献
30.
Natural products have been in use long before the introduction of modern drug therapies and are still used in various communities worldwide for the treatment of anterior eye disease. The aim of this review is to look at the current non-pharmaceutical modalities that have been tried and assess the body of existing evidence behind them. This includes alternative medicine, existing non-pharmaceutical therapy and more recent low and high tech solutions.A detailed search of all available databases including MEDLINE, Pubmed and Google was made to look for English-language studies for complementary and alternative treatment modalities (CAM), natural therapies and new modalities for anterior eye disease such as blepharitis, dry eye and microbial keratitis. We have included a broad discussion ranging from traditional treatments like honey and aloe vera which have been used for centuries, to the more recent technological advances like Intense Pulsed Light (IPL), LipiFlow and photoactivated chromophore for corneal cross linking in infectious keratitis (PACK-CXL).Alternative management strategies may have a role in anterior eye diseases and have a potential in changing the way we currently approach them. Some of the available CAM could play a role if incorporated in to current management practices of not only chronic diseases like blepharitis and dry eye, but also acute conditions with significant morbidity like microbial keratitis. Further large-scale randomized control trials stratified by disease severity are required to improve our understanding and to evaluate the use of non-pharmaceutical therapy against current practice. 相似文献