全文获取类型
收费全文 | 139篇 |
免费 | 8篇 |
专业分类
综合类 | 1篇 |
化学工业 | 26篇 |
金属工艺 | 5篇 |
机械仪表 | 4篇 |
建筑科学 | 4篇 |
能源动力 | 8篇 |
轻工业 | 2篇 |
水利工程 | 4篇 |
无线电 | 22篇 |
一般工业技术 | 21篇 |
冶金工业 | 4篇 |
原子能技术 | 2篇 |
自动化技术 | 44篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 3篇 |
2016年 | 10篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 9篇 |
2011年 | 8篇 |
2010年 | 5篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 4篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有147条查询结果,搜索用时 15 毫秒
31.
Luyang Li George Nagy Ashok Samal Sharad Seth Yihong Xu 《International Journal on Document Analysis and Recognition》2000,2(4):177-185
Our proposed approach to text and line-art extraction requires accurately locating a text-string box and identifying external line vectors incident on the box. The results of extrapolating these vectors inside the box are passed to an experimental single-font optical character reader (OCR) program, specifically trained for the font used for street labels. In the first evaluation experiment, automated techniques are used to identify the boxes and the line vectors. In the second, more comprehensive, experiment an operator marks these using a graphical user interface. OCR results on 544 instances of overlapped street-name boxes show the following improvements due to the integrated processing: the error rate is reduced from 4.1% to 2.0% for characters and from 11.8% to 6.4% for words. 相似文献
32.
The ability to stay on pace with Moore's law has been critical in providing for exponentially increasing computation capabilities per unit cost, and thus regularly enabling new applications. Maintaining this pace has always been challenging, but the challenges loom even larger as we approach the physical and economic limits of technology scaling. The resulting stress already is causing many companies to move toward fabless and fablight business models, with increased emphasis on system-level design technology. Another observable trend is the decline of ASICs and the corresponding growth in programmable platforms. These changes challenge traditional design technologies such as test and verification, and their interaction with emerging issues related to variability, reliability, and migration to post-silicon devices. This article proposes a roadmap of potential solutions for the future, based on managing massive concurrency, increasing self-adaptivity and resiliency, and adopting new computation models. 相似文献
33.
Secure multidimensional range queries over outsourced data 总被引:1,自引:0,他引:1
Bijit Hore Sharad Mehrotra Mustafa Canim Murat Kantarcioglu 《The VLDB Journal The International Journal on Very Large Data Bases》2012,21(3):333-358
In this paper, we study the problem of supporting multidimensional range queries on encrypted data. The problem is motivated by secure data outsourcing applications where a client may store his/her data on a remote server in encrypted form and want to execute queries using server??s computational capabilities. The solution approach is to compute a secure indexing tag of the data by applying bucketization (a generic form of data partitioning) which prevents the server from learning exact values but still allows it to check if a record satisfies the query predicate. Queries are evaluated in an approximate manner where the returned set of records may contain some false positives. These records then need to be weeded out by the client which comprises the computational overhead of our scheme. We develop a bucketization procedure for answering multidimensional range queries on multidimensional data. For a given bucketization scheme, we derive cost and disclosure-risk metrics that estimate client??s computational overhead and disclosure risk respectively. Given a multidimensional dataset, its bucketization is posed as an optimization problem where the goal is to minimize the risk of disclosure while keeping query cost (client??s computational overhead) below a certain user-specified threshold value. We provide a tunable data bucketization algorithm that allows the data owner to control the trade-off between disclosure risk and cost. We also study the trade-off characteristics through an extensive set of experiments on real and synthetic data. 相似文献
34.
35.
Anionic bisphosphodiester gemini surfactants with two different spacer moieties and varying alkyl chain lengths were synthesized and investigated for their surface active properties. The equilibrium and dynamic surface tension studies were carried out using the Wilhelmy plate technique and maximum bubble pressure method respectively. It was found that these gemini surfactants possess lower critical micellar concentration values, and reduce the surface tension to a greater extent in comparison with the conventional analogues. The efficiency of the synthesized gemini surfactants was also evaluated. The results of surface activities obtained were correlated with the structures of gemini surfactants. The dynamic surface tension measurements showed that the geminis with long chains adsorb very slowly at the air/water interface within the time span of measurements. These gemini surfactants showed low foamability. 相似文献
36.
Qi Han Sharad Mehrotra Nalini Venkatasubramanian 《Journal of Parallel and Distributed Computing》2007
Sensors are typically deployed to gather data about the physical world and its artifacts for a variety of purposes that range from environment monitoring, control, to data analysis. Since sensors are resource constrained, often sensor data is collected into sensor databases that reside at (more powerful) servers. A natural tradeoff exists between resources (bandwidth, energy) consumed and the quality of data collected at the server. Blindly transmitting sensor updates at a fixed periodicity to the server results in a suboptimal solution due to the differences in stability of sensor values and due to the varying application needs that impose different quality requirements across sensors. In order to adapt to these variations while at the same time optimizing the energy consumption of sensors, this paper proposes three different models and corresponding data collection protocols. We analyze all three models with a Markov state machine formulation, and either derive closed forms for the operation point of the data collection application or suggest algorithms for estimating this operating point to achieve a minimal energy consumption. We observe that the operating point depends on environmental characteristics and application quality requirements, which the proposed algorithms aim to accommodate. Our experimental results show significant energy savings compared to the naive approach to data collection. 相似文献
37.
Rajesh P. Raval Sharad G. Dixit 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1979,29(2):107-115
Removal of iron and titanium impurities in bauxite by selective chlorination has been obtained by controlling the addition doses of coke and restricting the temperatures to below 323 K. The chlorination of iron and titanium free bauxite has been studied as regards the effect of coke addition, Cl2 flow rates and partial pressures and temperatures. The rate equation 1-(1 - R)1/3 = kt has been shown to fit the experimental data. It is concluded that the diatomic Cl2 molecule does not dissociate to atomic Cl during chlorination. 相似文献
38.
Photobleaching and recovery of 488-nm excited fluorescence from resected human breast tissue samples have been studied. Profiles of photobleaching decay were seen to be faster in cancerous tissue than in those of the normal tissue. The reverse behavior was observed in profiles of recovery after photobleaching. A theoretical model based on one-dimensional diffusion theory has been developed to provide insight into the phenomena of fluorescence during photobleaching and recovery in a multiply scattering medium such as tissue. To understand photobleaching and recovery with the help of this theoretical model, we carried out experiments with model media that were prepared with authentic fluorophores, scatterers, and absorbers. The results of these studies suggest that the fluorescence photobleaching profiles are affected more by the absorption than by the scattering properties of a turbid medium such as tissue. In contrast, the scattering properties of the medium are found to affect the fluorescence recovery profiles to a greater extent. These observations could be related to the observed difference in fluorescence photobleaching and recovery profiles of normal and cancerous breast tissues. 相似文献
39.
Outbreaks of enterohemorrhagic Escherichia coli O157:H7 infections associated with lettuce and other leaf crops have occurred with increasing frequency in recent years. Contaminated manure and polluted irrigation water are probable vehicles for the pathogen in many outbreaks. In this study, the occurrence and persistence of E. coli O157:H7 in soil fertilized with contaminated poultry or bovine manure composts or treated with contaminated irrigation water and on lettuce and parsley grown on these soils under natural environmental conditions was determined. Twenty-five plots, each 1.8 by 4.6 m, were used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but treated with contaminated water) and five replication plots for each treatment. Three different types of compost, PM-5 (poultry manure compost), 338 (dairy manure compost), and NVIRO-4 (alkaline-stabilized dairy manure compost), and irrigation water were inoculated with an avirulent strain of E. coli O157:H7. Pathogen concentrations were 10(7) CFU/g of compost and 10(5) CFU/ml of water. Contaminated compost was applied to soil in the field as a strip at 4.5 metric tons per hectare on the day before lettuce and parsley seedlings were transplanted in late October 2002. Contaminated irrigation water was applied only once on the plants as a treatment in five plots for each crop at the rate of 2 liters per plot 3 weeks after the seedlings were transplanted. E. coli O157:H7 persisted for 154 to 217 days in soils amended with contaminated composts and was detected on lettuce and parsley for up to 77 and 177 days, respectively, after seedlings were planted. Very little difference was observed in E. coli O157:H7 persistence based on compost type alone. E. coli O157:H7 persisted longer (by > 60 days) in soil covered with parsley plants than in soil from lettuce plots, which were bare after lettuce was harvested. In all cases, E. coli O157:H7 in soil, regardless of source or crop type, persisted for > 5 months after application of contaminated compost or irrigation water. 相似文献
40.
This paper describes an efficient approach to record linkage. Given two lists of records, the record-linkage problem consists
of determining all pairs that are similar to each other, where the overall similarity between two records is defined based
on domain-specific similarities over individual attributes. The record-linkage problem arises naturally in the context of
data cleansing that usually precedes data analysis and mining. Since the scalability issue of record linkage was addressed
in [21], the repertoire of database techniques dealing with multidimensional data sets has significantly increased. Specifically,
many effective and efficient approaches for distance-preserving transforms and similarity joins have been developed. Based
on these advances, we explore a novel approach to record linkage. For each attribute of records, we first map values to a
multidimensional Euclidean space that preserves domain-specific similarity. Many mapping algorithms can be applied, and we
use the Fastmap approach [16] as an example. Given the merging rule that defines when two records are similar based on their attribute-level similarities,
a set of attributes are chosen along which the merge will proceed. A multidimensional similarity join over the chosen attributes
is used to find similar pairs of records. Our extensive experiments using real data sets show that our solution has very good
efficiency and recall.
Part of this article was published in [28]. In addition to the prior materials, this article contains more analysis, a complete proof, and more experimental results
that were not included in the original paper. 相似文献