全文获取类型
收费全文 | 993篇 |
免费 | 27篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 16篇 |
综合类 | 5篇 |
化学工业 | 256篇 |
金属工艺 | 16篇 |
机械仪表 | 27篇 |
建筑科学 | 14篇 |
矿业工程 | 1篇 |
能源动力 | 45篇 |
轻工业 | 55篇 |
水利工程 | 1篇 |
无线电 | 110篇 |
一般工业技术 | 243篇 |
冶金工业 | 81篇 |
原子能技术 | 6篇 |
自动化技术 | 148篇 |
出版年
2024年 | 4篇 |
2023年 | 18篇 |
2022年 | 31篇 |
2021年 | 47篇 |
2020年 | 41篇 |
2019年 | 41篇 |
2018年 | 43篇 |
2017年 | 30篇 |
2016年 | 44篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 82篇 |
2012年 | 40篇 |
2011年 | 50篇 |
2010年 | 51篇 |
2009年 | 36篇 |
2008年 | 43篇 |
2007年 | 41篇 |
2006年 | 37篇 |
2005年 | 28篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 25篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 13篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 7篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有1024条查询结果,搜索用时 15 毫秒
21.
Upadhyay J Joshi MJ Deshpande PP Sharma ML Navathe CP 《The Review of scientific instruments》2008,79(5):054701
In this paper, a ramp generator with programmable slope is presented. It consists of a high voltage step generator, followed by integrator. The capacitor and inductor in the integrator are designed such that they can be varied by a microcontroller. This circuit generates two bipolar ramps with fastest speed <1 ns and provides continuous speed variation from 6 to 30 ns for a ramp of 500 V. This is being developed as a part of automated streak camera for deflection of electron beam. 相似文献
22.
Sachin Singh Sushil Puradkar Yugyung Lee 《Information Systems and E-Business Management》2006,4(4):421-439
Ubiquitous computing refers to building a global computing environment where seamless and invisible access to computing resources is provided to the user. Pervasive computing deals with acquiring context knowledge from the environment and providing dynamic, proactive and context-aware services to the user. A Ubiquitous computing environment is created by sharing knowledge and information between Pervasive computing environments. In this paper we propose a framework that uses the potential of the Semantic Web to weave Pervasive computing environments into a Ubiquitous computing environment. We discuss how the collaboration of these Pervasive environments can create an effective Ubiquitous computing environment referred herein as the Integrated Global Pervasive Computing Framework (IGPF). We test the effectiveness of the Ubiquitous environment through a small scenario from a prototype system that we have implemented over this framework to handle medical emergency scenario. 相似文献
23.
Deshpande S. Thottan M. Sikdar B. 《Network and Service Management, IEEE Transactions on》2008,5(2):78-90
Being the primary interdomain routing protocol, Border Gateway Protocol (BGP) is the singular means of path establishment across the Internet. Therefore, misconfiguration errors in BGP routers result in failure to establish paths which in turn can cause several networks to become unreachable. In this paper, we first analyze data from recent BGP tables to show that misconfiguration errors occur very frequently in the Internet today. We then show theoretically and using real-world events the impact of these errors on routing stability. A scheme for real-time isolation of large-scale BGP misconfiguration events is then proposed in this paper. Our methodology is based on statistical techniques and is evaluated using data from past wellknown misconfiguration events. We show the effectiveness of our method as compared to the current state-of-the-art. 相似文献
24.
Sachin Bhalekar 《Signal, Image and Video Processing》2014,8(4):635-639
Differential-difference equations with multiple delays have applications in a variety of applied fields. We propose a prototype delay model introduced by Uçar involving two delays. Sufficient conditions for the stability of the model are given and used to study chaos. It is observed first time in the literature that the Uçar system shows not only two-scroll but also one-scroll chaotic attractors. 相似文献
25.
Aditya Telang P. Deepak Salil Joshi Prasad Deshpande Ranjana Rajendran 《Data mining and knowledge discovery》2014,28(5-6):1480-1502
The last decade has witnessed an unprecedented growth in availability of data having spatio-temporal characteristics. Given the scale and richness of such data, finding spatio-temporal patterns that demonstrate significantly different behavior from their neighbors could be of interest for various application scenarios such as—weather modeling, analyzing spread of disease outbreaks, monitoring traffic congestions, and so on. In this paper, we propose an automated approach of exploring and discovering such anomalous patterns irrespective of the underlying domain from which the data is recovered. Our approach differs significantly from traditional methods of spatial outlier detection, and employs two phases—(i) discovering homogeneous regions, and (ii) evaluating these regions as anomalies based on their statistical difference from a generalized neighborhood. We evaluate the quality of our approach and distinguish it from existing techniques via an extensive experimental evaluation. 相似文献
26.
Sumit K. Mishra Nabanita Saha S. Singh Chhemendra Sharma M. V. S. N. Prasad Sachin Gautam Amit Misra Abhishek Gaur Deepika Bhattu Subhasish Ghosh Anubhav Dwivedi Rosalin Dalai Debajyoti Paul Tarun Gupta Sachchida N. Tripathi R. K. Kotnala 《Mapan》2017,32(3):229-241
Estimation of the direct radiative forcing (DRF) by atmospheric particles is uncertain to a large extent owing to uncertainties in their morphology (shape and size), mixing states, and chemical composition. A region-specific database of the aforementioned physico-chemical properties (at individual particle level) is necessary to improve numerically-estimated optical and radiative properties. Till date, there is no detailed observation of the above mentioned properties over Kanpur in the Indo-Gangetic Plain (IGP). To fill this gap, an experiment was carried out at Kanpur (IITK; 26.52°N, 80.23°E, 142 m msl), India from April to July, 2011. Particle types broadly classified as (a) Cu-rich particles mixed with carbon and sulphur (b) dust and clays mixed with carbonaceous species (c) Fe-rich particles mixed with carbon and sulfur and (d) calcite (CaCO3) particles aged with nitrate, were observed. The frequency distributions of aspect ratio (AR; indicator of extent of particle non-sphericity) of total 708 particles from April to June reveal that particles with aspect ratio range >1.2 to ≤1.4 were abundant throughout the experiment except during June when it was found to shift to high AR range, >1.4 to ≤1.6 (followed with another peak of AR i.e. >2 to ≤2.4) due to dust storm conditions enhancing the occurrence of more non-spherical particles over the sampling site. The spherical particles (and close to spherical shape; AR range, 1.0 to ≤1.2) were found to be <20% throughout the experiment with a minimum (11.5%) during June. Consideration of Homogeneous Equivalent Sphere Approximation (HESA) in the optical/radiative model over the study region is found to be irrelevant during the campaign. 相似文献
27.
28.
29.
Amit K. Jaiswal Hemlata Chhabra Sachin S. Kadam Kishore Londhe Vivek P. Soni Jayesh R. Bellare 《Materials science & engineering. C, Materials for biological applications》2013,33(5):2926-2936
The aim of this study was to compare physico-chemical and biological properties of hydroxyapatite (HA) and hardystonite (HS) based composite scaffolds. Hardystonite (Ca2ZnSi2O7) powders were synthesized by a sol–gel method while polycaprolactone–hardystonite (PCL–HS) and polycaprolactone–hydroxyapatite (PCL–HA) were fabricated in nanofibrous form by electrospinning. The physico-chemical and biological properties such as tensile strength, cell proliferation, cell infiltration and alkaline phosphatase activity were determined on both kinds of scaffolds. We found that PCL–HS scaffolds had better mechanical strength compared to PCL–HA scaffolds. Addition of HA and HS particles to PCL did not show any inhibitory effect on blood biocompatibility of scaffolds when assessed by hemolysis assay. The in vitro cellular behavior was evaluated by growing murine adipose-tissue-derived stem cells (mE-ASCs) over the scaffolds. Enhanced cell proliferation and improved cellular infiltrations on PCL–HS scaffolds were observed when compared to HA containing scaffolds. PCL–HS scaffolds exhibited a significant increase in alkaline phosphatase (ALP) activity and better mineralization of the matrix in comparison to PCL–HA scaffolds. These results clearly demonstrate the stimulatory role of Zn and Si present in HS based composite scaffolds, suggesting their potential application for bone tissue engineering. 相似文献
30.