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排序方式: 共有450条查询结果,搜索用时 31 毫秒
91.
92.
Machine Intelligence Research - Extracting the three-dimensional (3D) information including location and height of a pedestrian is important for vision-based intelligent traffic monitoring systems.... 相似文献
93.
用水量核算方法是最严格水资源管理制度实施的一项技术支撑。以山东济宁市梁山县为研究区,采用FAO(国际粮农组织)推荐的Penman-Monteith公式,计算了该县3种主要农作物的逐日作物需水量及净灌溉需水量。研究中考虑到研究区的作物种植面积、灌溉水利用系数等因素提出理论需水量和折算系数的概念,通过推求理论需水量与实际用水量的折算系数,对2011年和2012年梁山县灌溉用水量统计数据进行核算,核算的相对误差分别为0.08%和-1.52%,核算结果较好。 相似文献
94.
Ay?e Çeçen Erb?l 《Chemical engineering science》2003,58(20):4739-4745
The distribution of flow between the annulus and the draft tube sections in a liquid phase spout-fluid bed with a draft tube was studied in a flat-based semi-circular column of diameter equipped with a semi-circular draft tube of diameter at superficial fluid velocities well above the minimum fluidization velocity. The particles used were glass spheres of diameter, and the spouting medium was tap water. A sodium chloride solution was injected into the reactor and the response recorded to determine the flow distribution between the draft tube and the annulus sections. The responses of the tracer injections prove that part of the flow originating from the annulus inlet leaks into the draft tube when any amount of annulus inlet flow is present. This finding makes a significant contribution to the understanding of the entrance region below a draft tube which has been modeled as a spout-fluid bed where fluid enters the annulus region based on the pressure distribution at the spout-annulus interface while the flow is in the radial direction from the spout into the annulus. This work shows that there is cross flow in the entrance region resulting in fluid exchange between the streams originating from the spouting inlet nozzle and the annulus inlet flow.The amount of leakage is found to increase with increasing inlet flow rates. An empirical correlation is developed to predict the fraction of the leakage of the annulus inlet flow. The superficial fluid velocity through the draft tube is found to vary linearly with the total flow rate through the bed under the experimental conditions studied. The pressure distributions in the entrance region favor the leakage of fluid from the annulus inlet flow into the draft tube. 相似文献
95.
This paper investigates the effectiveness of participatory design study in rendering the students' capability of producing innovative design solutions to problems with uncertainties with which the students have no prior experience. At the project, the students were given a case to work on augmented reality technology with which they had no previous experience and design a tactical interface for sailing boats, a field they had no competence in. While the students were asked to develop proposals for this design problem with which they were inexperienced, a two-stage study was conducted to enable them to produce ideas on the topic. This paper discusses the impacts of such a participatory method in terms of design education. At the end of our study, it was observed that the students were positively influenced by the process in which they worked collaboratively with an expert user group. 相似文献
96.
As the application layer in embedded systems dominates over the hardware, ensuring software quality becomes a real challenge.
Software testing is the most time-consuming and costly project phase, specifically in the embedded software domain. Misclassifying
a safe code as defective increases the cost of projects, and hence leads to low margins. In this research, we present a defect
prediction model based on an ensemble of classifiers. We have collaborated with an industrial partner from the embedded systems
domain. We use our generic defect prediction models with data coming from embedded projects. The embedded systems domain is
similar to mission critical software so that the goal is to catch as many defects as possible. Therefore, the expectation
from a predictor is to get very high probability of detection (pd). On the other hand, most embedded systems in practice are commercial products, and companies would like to lower their costs
to remain competitive in their market by keeping their false alarm (pf) rates as low as possible and improving their precision rates. In our experiments, we used data collected from our industry
partners as well as publicly available data. Our results reveal that ensemble of classifiers significantly decreases pf down
to 15% while increasing precision by 43% and hence, keeping balance rates at 74%. The cost-benefit analysis of the proposed
model shows that it is enough to inspect 23% of the code on local datasets to detect around 70% of defects. 相似文献
97.
Selma Ayşe Özel 《Expert systems with applications》2011,38(4):3407-3415
The incredible increase in the amount of information on the World Wide Web has caused the birth of topic specific crawling of the Web. During a focused crawling process, an automatic Web page classification mechanism is needed to determine whether the page being considered is on the topic or not. In this study, a genetic algorithm (GA) based automatic Web page classification system which uses both HTML tags and terms belong to each tag as classification features and learns optimal classifier from the positive and negative Web pages in the training dataset is developed. Our system classifies Web pages by simply computing similarity between the learned classifier and the new Web pages. In the existing GA-based classifiers, only HTML tags or terms are used as features, however in this study both of them are taken together and optimal weights for the features are learned by our GA. It was found that, using both HTML tags and terms in each tag as separate features improves accuracy of classification, and the number of documents in the training dataset affects the accuracy such that if the number of negative documents is larger than the number of positive documents in the training dataset, the classification accuracy of our system increases up to 95% and becomes higher than the well known Naïve Bayes and k nearest neighbor classifiers. 相似文献
98.
Yu CF Chen SH Xie WJ Lin YS Shen CY Tsai SJ Sung CW Ay C 《Microscopy research and technique》2008,71(1):1-4
In this study, conducting atomic force microscopy was employed to investigate the nanoscale surface electrical properties of zinc oxide (ZnO) films prepared by pulsed laser deposition (PLD) at different substrate temperatures for use as anode materials in polymer light-emitting diodes. The results show that the surface conductivity distribution of ZnO is related to its surface structure. At substrate temperatures of 150-200 degrees C, the conducting regions may cover over 90% of the ZnO thin-film surface, thus providing the best local conductivity. Moreover, heating at substrate temperatures of above 250 degrees C can effectively make the conductivity on the ZnO surface uniform. In particular, at substrate temperatures of around 300 degrees C, the conducting regions where currents are between 1 and 2 muA may cover as much as 83% of the surface, and furthermore, the transmission ratio in the visible range is higher than 80%. This is a rather ideal production temperature for the PLD for ZnO films. 相似文献
99.
This study was performed to investigate certain major and toxic metal concentrations in different tissues of three demersal fish species (Triglia lucerna, Lophius budegassa, Solea lascaris). Generally, skin and liver exhibited higher metal concentrations than did muscle. Sodium and arsenic concentrations were found at higher levels in muscle tissues than in livers and skin, while zinc and nickel in different organs were classified as follows: skin > liver > muscle tissues. The concentrations of trace metals in fish samples indicated that S. lascaris was more contaminated than were other fish species, followed by L. budegassa and T. lucerna. It may be concluded that consumption of these species from this region is not likely to pose a threat for human health. However, although the concentrations are below the limit values for fish muscles, a potential danger may emerge in the future, depending on domestic waste waters and industrial activities in the region. Therefore, further monitoring programmes should be conducted. 相似文献
100.
Mehmet Kiliç Yaşar Karabul Zeynep Güven Özdemir Seda Erdönmez Ayşe Evrim Bulgurcuoğlu Serço Serkis Yeşilkaya Mustafa Okutan Orhan İçelli 《Bulletin of Materials Science》2018,41(2):52
The main aim of this study is to produce added polypyrrole (PPy) borax composites with high dielectric properties for technological applications. For this purpose, PPy–borax composites with different borax concentrations varying from 10 to 50 wt% have been prepared. To reveal their structural and morphological attributes, the composites have been characterized by Fourier-transform infrared spectroscopy and scanning electron microscopy. The real and imaginary parts of complex dielectric function, the imaginary component of complex electrical modulus and ac conductivity have been investigated at room temperature as a function of frequency in the range 100 Hz–15 MHz. It has been found that addition of borax increases the dielectric constant of pure PPy. In this respect, PPy–borax composites with the highest dielectric constant at low frequency may be utilized in charge storing devices. On the other hand, the dielectric loss is also very high in low-frequency region for the composites with high borax content. Exploiting this property, the material may also be used in decoupling capacitor applications. The relaxation mechanisms of the samples have also been determined as non-Debye type. The Nyquist curves of the samples have been analysed for calculating the grain and grain boundary resistance and capacitance values. In conclusion, borax has a promising potential to be used as a cheap and effective filler for improving the dielectric properties of PPy polymer. 相似文献