全文获取类型
收费全文 | 1724篇 |
免费 | 74篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 24篇 |
综合类 | 2篇 |
化学工业 | 352篇 |
金属工艺 | 51篇 |
机械仪表 | 54篇 |
建筑科学 | 35篇 |
矿业工程 | 2篇 |
能源动力 | 117篇 |
轻工业 | 106篇 |
水利工程 | 11篇 |
石油天然气 | 4篇 |
无线电 | 234篇 |
一般工业技术 | 394篇 |
冶金工业 | 165篇 |
原子能技术 | 17篇 |
自动化技术 | 243篇 |
出版年
2024年 | 5篇 |
2023年 | 30篇 |
2022年 | 75篇 |
2021年 | 93篇 |
2020年 | 81篇 |
2019年 | 62篇 |
2018年 | 102篇 |
2017年 | 80篇 |
2016年 | 75篇 |
2015年 | 49篇 |
2014年 | 67篇 |
2013年 | 131篇 |
2012年 | 84篇 |
2011年 | 90篇 |
2010年 | 72篇 |
2009年 | 49篇 |
2008年 | 59篇 |
2007年 | 71篇 |
2006年 | 40篇 |
2005年 | 29篇 |
2004年 | 23篇 |
2003年 | 13篇 |
2002年 | 26篇 |
2001年 | 24篇 |
2000年 | 14篇 |
1999年 | 18篇 |
1998年 | 38篇 |
1997年 | 43篇 |
1996年 | 26篇 |
1995年 | 13篇 |
1994年 | 16篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 14篇 |
1990年 | 8篇 |
1989年 | 8篇 |
1988年 | 8篇 |
1987年 | 9篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1973年 | 5篇 |
排序方式: 共有1811条查询结果,搜索用时 15 毫秒
61.
62.
Polypropylene random copolymer/MWCNT nanocomposites: Isothermal crystallization kinetics,structural, and morphological interpretations
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This article describes the crystallization process of polypropylene random copolymer (PPCP) under isothermal conditions in presence of varying amounts of multiwalled carbon nanotubes (MWCNT) ranging from 0.5 to 4.0% w/w. Increase in the crystallization temperature under dynamic conditions confirmed the nucleating behavior of MWCNTs, which was also corroborated by crystallization studies under isothermal conditions. The crystallization kinetics was analyzed using Avrami equation and the parameters such as Avrami exponent, the equilibrium melting temperature and fold surface energy for the crystallization of PPCP chains in nanocomposites were obtained from the calorimetric data in order to determine the effect of MWCNTs on these parameters. Spherulitic growth of PPCP crystals was also investigated as a function of time and MWCNT content using hot stage polarizing microscope. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41734. 相似文献
63.
64.
Bhupander Kumar V. K. Verma Jyoti Tyagi C. S. Sharma A. B. Akolkar 《Polycyclic Aromatic Compounds》2016,36(5):729-744
This study aims to investigate the level of priority polycyclic aromatic hydrocarbons (PAHs) and identification of their potential sources in residential soils. During the study, a total 36 soil samples collected from twelve residential locations at Sahibabad-Ghaziabad area of western Uttar Pradesh, India, a constituted part of the National Capital Region of India. Samples extracted using ultrasonication, cleaned with silica and analyzed by diode array detector–high-performance liquid chromatography using acetonitrile/water as mobile phase. The 25th and 75th percentile concentration of ∑PAHs was 264 μg kg?1 and 584 μg kg?1, respectively, with mean and median of 445 μg kg?1 and 421 μg kg?1. The detection frequency of PAHs in all samples was lower for low molecular weight PAHs (19%) than high molecular weight PAHs (81%). The concentration of seven probable carcinogenic PAHs accounted for 67% of the ∑PAHs. PAHs toxicity potential as benzo(a)pyrene toxicity equivalent ranged between 2.52–253 μg BaPTEQ kg?1. Composition profile of PAHs with different aromatic rings and selected diagnostic molecular ratios suggested the local pyrogenic sources of PAHs from vehicular emissions, diesel engines, biomass combustion, gasoline, and coal combustions. 相似文献
65.
Rih‐Teng Wu Ankush Singla Mohammad R. Jahanshahi Elisa Bertino Bong Jun Ko Dinesh Verma 《Computer-Aided Civil and Infrastructure Engineering》2019,34(9):774-789
Health monitoring of civil infrastructures is a key application of Internet of things (IoT), while edge computing is an important component of IoT. In this context, swarms of autonomous inspection robots, which can replace current manual inspections, are examples of edge devices. Incorporation of pretrained deep learning algorithms into these robots for autonomous damage detection is a challenging problem since these devices are typically limited in computing and memory resources. This study introduces a solution based on network pruning using Taylor expansion to utilize pretrained deep convolutional neural networks for efficient edge computing and incorporation into inspection robots. Results from comprehensive experiments on two pretrained networks (i.e., VGG16 and ResNet18) and two types of prevalent surface defects (i.e., crack and corrosion) are presented and discussed in detail with respect to performance, memory demands, and the inference time for damage detection. It is shown that the proposed approach significantly enhances resource efficiency without decreasing damage detection performance. 相似文献
66.
Sarika Verma Mishra Deepti Sanghi S. K. Srivastava A. K. Amritphale S. S. 《Protection of Metals and Physical Chemistry of Surfaces》2019,55(1):65-71
Protection of Metals and Physical Chemistry of Surfaces - We report a facile and reproducible method to synthesize advanced, homogenized, hybrid, nanoflower of thorium oxide and thorium oxalate... 相似文献
67.
Rajesh B. Gujar Parveen K. Verma Bholanath Mahanty Seraj A. Ansari Dibakar Goswami 《分离科学与技术》2020,55(14):2560-2569
ABSTRACT Solvent extraction studies were performed to understand the extraction behavior of Np4+ and NpO2 2+ from acidic feeds with CMPO (octyl (phenyl)-N,N-diisobutyl carbamoyl methyl phosphine oxide) dissolved in 1-butyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide, a water immiscible ionic liquid. Slope analyses on the distribution data revealed the extraction of ML2 type species, where M = Np4+ or NpO2 2+, and L = CMPO. Studies were also carried out with Pu4+ and UO2 2+ under identical conditions. The nature of the extracted species was found to vary with the nature of the ionic species. 相似文献
68.
Tarun Sai Ghanta Sridhar Aparna Namrata Verma Doddipatla Purnima 《Polymer Engineering and Science》2020,60(8):1717-1759
Polyamide 6 (PA6)-based composites are of evolving interest due to its high strength, wear resistance, and barrier properties. The use of binary composites mostly with nanomaterial and glass fibers has been reviewed and presented in literature. However to obtain a balance of properties like stiffness, toughness, and strength along with cost reduction, ternary composites of PA6 have been designed. To achieve the balance, PA6 blend-based composites, with combination of microfiller/nanofiller or PA6 with combination micro-microfiller, PA6 with microfiller/nanofiller and fiber have been designed. The properties of PA6-based ternary hybrid composites depend on type of dispersed phase used, presence of compatibilizer, type of filler used (nanofiller or microfiller or fiber or hybrid) and combination of fillers used. However, a review in this direction is not available in literature. Here, in this study, an overall understanding of various fillers, dispersed phase, and their combinations can be understood along with the discussion on effect of these on tensile properties and morphology of hybrid composite. In this study, an attempt has been made to review the various fillers and dispersed phase and their combinations which have been used in designing the PA6 hybrid composite with good balance of stiffness, toughness, and strength. 相似文献
69.
Silicon - Silicon carbide piezoresistive pressure sensor is more suitable for harsh environment due to its wide bandgap, corrosion tolerance, excellent chemical inertness, high Young’s... 相似文献
70.
This paper presents two novel six-axis magnetic-levitation (maglev) stages capable of nanoscale positioning. These stages have very simple and compact structures, which is advantageous to meet the demanding positioning requirements of next-generation nanomanipulation and nanomanufacturing. Six-axis motion generation is accomplished by the minimum number of actuators and sensors. The first-generation maglev stage, namely the Δ-stage, is capable of generating translation of 300 μm and demonstrates position resolution better than 2 nm root-mean-square (rms). The second-generation maglev stage, namely the Y-stage, is capable of positioning at a resolution better than 3 nm rms over a planar travel range of 5 mm × 5 mm. A novel actuation scheme was developed for the compact structure of this stage that enables six-axis force generation with just three permanent-magnet pieces. This paper focuses on the design and precision construction of the actuator units, the moving platens, and the stationary base plates. The performance of the two precision positioners is compared in terms of their positioning and load-carrying capabilities and ease of manufacture. Control system design for the two positioners is discussed and an experimental plant transfer function model is presented for the Y-stage. The superiority of the developed instruments is also demonstrated over other prevailing precision positioning systems in terms of the travel range, resolution, and dynamic range. The potential applications of the maglev positioners include semiconductor manufacturing, microfabrication and assembly, nanoscale profiling, and nanoindentation. 相似文献