全文获取类型
收费全文 | 730篇 |
免费 | 30篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 14篇 |
化学工业 | 136篇 |
金属工艺 | 11篇 |
机械仪表 | 33篇 |
建筑科学 | 16篇 |
矿业工程 | 2篇 |
能源动力 | 58篇 |
轻工业 | 36篇 |
水利工程 | 3篇 |
无线电 | 99篇 |
一般工业技术 | 160篇 |
冶金工业 | 80篇 |
原子能技术 | 4篇 |
自动化技术 | 110篇 |
出版年
2023年 | 11篇 |
2022年 | 11篇 |
2021年 | 23篇 |
2020年 | 20篇 |
2019年 | 17篇 |
2018年 | 26篇 |
2017年 | 29篇 |
2016年 | 26篇 |
2015年 | 18篇 |
2014年 | 12篇 |
2013年 | 54篇 |
2012年 | 26篇 |
2011年 | 39篇 |
2010年 | 23篇 |
2009年 | 21篇 |
2008年 | 32篇 |
2007年 | 36篇 |
2006年 | 27篇 |
2005年 | 22篇 |
2004年 | 20篇 |
2003年 | 8篇 |
2002年 | 12篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 15篇 |
1995年 | 12篇 |
1994年 | 12篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1971年 | 3篇 |
排序方式: 共有762条查询结果,搜索用时 15 毫秒
1.
Bharat Kumar Reddy Sanapalli Shivaramakrishnan Balasubramanian Jawahar Natarajan Uday Krishna Baruah 《Drug development and industrial pharmacy》2018,44(10):1650-1658
5-Aminosalicylic acid (5-ASA) is an aminosalicylate anti-inflammatory drug, which is also known as mesalazine or mesalamine. Currently employed in treating inflammatory bowel disease, ulcerative colitis, inflamed anus or rectum, and maintain remission in Crohn's disease. Evidence from the researchers highlighted its significant re-epithelization in allergic asthma, aphthous, and gastric ulcerative conditions. The objective of the study was to formulate the pluronic lecithin organogel (PLO) containing 5-ASA and evaluate its wound-healing ability in a full thickness excision wound rat model. The data obtained from in silico docking studies revealed 5-ASA is having an affinity towards the transforming growth factor-beta (TGF-β) specifically towards beta1. Among various formulations prepared (F1 to F8), F1, and F6 have shown a maximum in vitro drug release with optimum pH and viscosity. From MTT assay it was found that selected PLO formulations showed no toxicity and enhanced cell proliferation in HaCaT cell lines. In vivo wound-healing studies in albino Wistar rats has revealed that PLO accelerates wound closure and reepithelization to the statistically significant level on day 3 (p?.05) in comparison with untreated wounds. In conclusion, the overall results suggest that 5-ASA PLO gel is a potential therapeutic option for the treatments of wounds, however, further studies are highly warrened to determine the various mechanisms of 5-ASA in regulating the cell migration and reepithelization in wound healing to outspread its use in clinics. 相似文献
2.
Jonathan Sampath Franklyne Swati Iyer Andrew Ebenazer Amitava Mukherjee Natarajan Chandrasekaran 《International Journal of Food Science & Technology》2019,54(9):2802-2810
Many human acid tolerant bacterial and fungal pathogens can be transmitted through the consumption of the contaminated fruit juices. We aim to formulate essential oil nanoemulsions (basil, black seed, turmeric, clove & cinnamon), determine their ability to clear contamination by food borne bacterial pathogens from fruit juices. The antibacterial activity of the optimised formulations was tested in the fruit juices against bacterial pathogens causing gastrointestinal tract infections. The minimum bactericidal concentration (MBC) of clove emulsions ranged from 15.6 to 25 μL mL−1. Cinnamon oil emulsion had an MBC ranging between 15 and 31 μL mL−1. At MBC, cinnamon oil emulsions caused a 6log10 decrease in viable counts by 8 h and maintained the sterility of fruit juices for 7 days at ambient temperature. Thus, clove and cinnamon microemulsions can be used as juice additives to control food borne bacterial pathogens and maintain the bacterial sterility of fruit juices. 相似文献
3.
4.
In this article, we report the influence of organic modifier structure (alkyl chain length C8-C20, single vs ditallow) and thereby, the effect of hydrophobicity on the structure, thermal and mechanical properties of poly(methyl methacrylate) (PMMA)-clay hybrids. Melt processed PMMA-clay hybrids were characterized using wide-angle X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. The organoclays having an alkyl chain length of more than 12 CH2 groups resulted in the formation of nanocomposites. The glass transition temperature (Tg) of PMMA increased in the presence of clay. The mean-field lattice model was used to predict the free energy for nanocomposite formation, which showed a reasonable match with the experimental results and provided a general guideline for the proper selection of polymer and organoclay (ie, organic modifier) to obtain nanocomposite. Tensile modulus showed maximum improvement of 58% for the nanocomposites compared to 9% improvement for the composites. Tensile modulus increased with increases in the alkyl chain length of the organic modifier and clay loading. The level of improvement for the tensile properties of nanocomposites prepared from primary and secondary ammonium-modified clay is the same as that obtained with the commercial organoclays. 相似文献
5.
Tittu Varghese Mathew Jayamanideep Rebbagondla Sundararajan Natarajan 《International journal for numerical methods in engineering》2020,121(19):4329-4346
Nouy and Clement introduced the stochastic extended finite element method to solve linear elasticity problem defined on random domain. The material properties and boundary conditions were assumed to be deterministic. In this work, we extend this framework to account for multiple independent input uncertainties, namely, material, geometry, and external force uncertainties. The stochastic field is represented using the polynomial chaos expansion. The challenge in numerical integration over multidimensional probabilistic space is addressed using the pseudo-spectral Galerkin method. Thereafter, a sensitivity analysis based on Sobol indices using the derived stochastic extended Finite Element Method solution is presented. The efficiency and accuracy of the proposed novel framework against conventional Monte Carlo methods is elucidated in detail for a few one and two dimensional problems. 相似文献
6.
Mani Balamurugan Hui‐Yun Jeong Venkata Surya Kumar Choutipalli Jung Sug Hong Hongmin Seo Natarajan Saravanan Jun Ho Jang Kang‐Gyu Lee Yoon Ho Lee Sang Won Im Venkatesan Subramanian Sun Hee Kim Ki Tae Nam 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(25)
The electrochemical reduction of carbon dioxide (CO2) to hydrocarbons is a challenging task because of the issues in controlling the efficiency and selectivity of the products. Among the various transition metals, copper has attracted attention as it yields more reduced and C2 products even while using mononuclear copper center as catalysts. In addition, it is found that reversible formation of copper nanoparticle acts as the real catalytically active site for the conversion of CO2 to reduced products. Here, it is demonstrated that the dinuclear molecular copper complex immobilized over graphitized mesoporous carbon can act as catalysts for the conversion of CO2 to hydrocarbons (methane and ethylene) up to 60%. Interestingly, high selectivity toward C2 product (40% faradaic efficiency) is achieved by a molecular complex based hybrid material from CO2 in 0.1 m KCl. In addition, the role of local pH, porous structure, and carbon support in limiting the mass transport to achieve the highly reduced products is demonstrated. Although the spectroscopic analysis of the catalysts exhibits molecular nature of the complex after 2 h bulk electrolysis, morphological study reveals that the newly generated copper cluster is the real active site during the catalytic reactions. 相似文献
7.
Natarajan Anand Remigius W. Dheelibun Guo Yi Keller Jonathan 《Forschung im Ingenieurwesen》2021,85(2):395-404
Forschung im Ingenieurwesen - In this article, the type of roller slip behavior that may result in the formation of white-etching cracks (WECs) in wind turbine gearbox bearings is identified.... 相似文献
8.
9.
Interaction of Bacillus polymyxa with calcite, hematite, corundum and quartz resulted in significant surface chemical changes not only of the cells but also in the minerals. Both the cell surfaces as well as quartz particles were rendered more hydrophobic after mutual interaction, whilst the rest of the minerals exhibited enhanced hydrophilicity after interaction with the bacteria. The bacteria were also observed to be capable of dissolving calcite, hematite and corundum and biosorbing the dissolved metal ions to varying extents. An excess of polysaccharides could be observed on biotreated calcite, hematite and corundum while the predominance of a protein-based metabolic product was evident on quartz surfaces. The utility of bioprocessing in the beneficiation of the above minerals through bioflotation and bioflocculation is demonstrated. 相似文献
10.
K. S. Sivakumaran 《Engineering Structures》1988,10(4):239-248
In the limit states design of steel building frames, usually simplifying assumptions are made with regard to the behaviour of beam-to-column connections. The Canadian standard for steel buildings recognizes three such sets of assumptions. One of them is the ‘special simple construction’ in which the beam-to-column connections are assumed to be completely free (pinned) to resist gravity loads and are assumed to be ‘rigid’ to resist the lateral loads due to earthquake or wind. Such connections are then designed for moments due to lateral loads only, and thus they are usually flexible. This paper is concerned with the influence of the connection flexibility and the strength on the overall strength and stiffness of steel building frames. The study considers 10 storey and 20 storey office buildings. The first part of the paper illustrates the analysis and design of the 10 storey building on the basis of ‘special simple construction’. By using realistic connection behaviour, the frames were subjected to equivalent static loads due to wind or earthquake and El Centro, 1940 earthquake excitation. In the nonlinear static analysis the building frames were subjected to specified gravity loads and incremental lateral loads until failure. In the nonlinear dynamic analysis the buildings were subjected to specified gravity loads and 70% of El Centro, 1940 earthquake excitation. For comparison purposes the frames were analysed twice, first assuming rigid connections and then with flexible connections. The static analyses results show that the connection flexibility increases the building deflections at specified loads, but the strength is only marginally affected. The dynamic analyses results show an increase in deflections and also generally an increase in column bending moments due to connection flexibility and the associated strength. 相似文献