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101.
《Expert systems with applications》2014,41(5):2574-2581
We describe in this paper a new methodology for blood alcohol content (BAC) estimation of a subject. Rather than using external devices to determine the BAC value of a subject, we perform a behaviour analysis of this subject using intelligent systems. We monitor the user’s actions in an ordinary task and label those data to various measured BAC values. The obtained data-set is then used to train learning systems to detect alcoholic consumption and perform BAC estimation. We obtain good results on a mono-user base, and lower results with multiple users. We improve the results by combining multiple classifiers and regression algorithms. 相似文献
102.
The availability of a system or equipment is one of the crucial characteristics that measures the customer satisfaction and strongly influences his final choice decision between concurrent products. The aim of this work is to provide an approach to improve the products availability assessment by taking into account the safety criteria by considering the use situations at design stage. Our work focuses on the routine design of complex products. The availability is often simply estimated considering reliability and maintainability. Basically, the intrinsic availability is the probability that it is operating satisfactorily at any point in time when used under conditions stated by design specifications. The time considered includes operating time and active repair time. Thus, intrinsic availability excludes from consideration all other times in the product lifecycle such as: accident management time, storage time, administrative time or logistic time. But many studies show that the loss of availability performance is also due to accidents that occur in different unforeseeable utilization situations. This engenders stops of the system to ensure the users safety according to standards recommendations. In this purpose, we consider the structural product architecture and the different use cases that correspond to the operational states and downtimes due to stop events that may happen during the utilization like failures, maintenance tasks and accidents. Then, we propose a product behavioral analysis including the use cases to describe interactions between the product and users or maintenance operators. We use Markov chains to model the use cases corresponding to operating time (OT), maintenance time (MT) and preparing time after accidents (RT). Then these three parameters are considered to specify a generic approach to improve the availability assessment. Such an approach provides the traceability of the product behavior along its lifecycle. In this way, the main causes of stop can be identified and this may guide the designer for improving the availability of the product future versions. To validate our approach, an application is presented considering a printing line. The comparison of our simulation considering an industrial case study shows a good agreement about the influence of safety on the availability. 相似文献
103.
Despite the apparent maturity of the learning design field, and the variety of tooling available to support it, adoption among the teacher community (one of its alleged main targets) is still low. There is a lack of research on teachers' perception and use of different technological learning design tools, as existing evaluations are often restricted to a single tool. In order to explore whether there are common factors hampering teacher adoption, and which tool features might appeal to different teachers, more studies involving multiple authoring tools are needed. This paper provides a first step in this direction, describing a mixed methods study performed around a professional development workshop with 18 university teachers from multiple disciplines. This workshop exposed teachers to two different authoring tools (WebCollage and EDIT2), as they learned to create computer-supported collaborative learning (CSCL) designs and implement them. The findings of our interpretive study (which included questionnaires, observations, or group discussion recordings) support the idea that there is no single tool or set of features that are globally perceived as better, although our evidence also highlights certain factors as important for participant teachers – amongst others, the integration of learning designs with the ICT platforms for enactment, as well as with other tools that they already use in their everyday practice. 相似文献
104.
《Reactive and Functional Polymers》2007,67(3):202-209
A chelating polymeric sorbent was developed by functionalizing poly(glycidyl methacrylate-co-trimethylolpropane trimethacrylate), poly(GMA-co-TRIM), with N-methylglucamine (MG) via a simple post-grafting route. The resulting well-defined millimeter-sized spheres of poly(GMA-co-TRIM)–MG had permanent macropore structures and low swelling degree, with accessible ligands of 1.84 mmol/g. The boron adsorption behavior of the sorbent was studied in batch mode by varying different parameters like the pH value, the initial concentration of boron and the adsorption time under noncompetitive conditions. It was found that the sorbent always maintained the high capacity between pH 2.6 and 8.6, in which the optimum pH was 7.5. The adsorption behavior of the sorbent obeyed the Langmuir isotherm well. The adsorption capacity of the sorbent for boron was in the same level as that of a commercially available N-methylglucamine-type polystyrene resin. However, it adsorbed boron more quickly. The sorbent also showed good durability and reusability through the fixed-bed adsorption tests. The study on the separation of boron from brine of salt lake showed a high selectivity of the sorbent, though the capacity for boron decreased due to the interference of diverse ions in brine. 相似文献
105.
Crystal structure and microwave dielectric properties of (Ba1−αSrα)6−3xSm8+2xTi18O54 solid solutions
《Journal of the European Ceramic Society》2006,26(10-11):2035-2038
The tungstenbronze-type-like (Ba1−αSrα)6−3xR8+2xTi18O54 (R = rare earth) solid solutions have been studied. Microwave dielectric properties of these solid solutions link to the substitution of large cations such as Ba ions by small Sr ions. In these solid solutions for x = 0, the quality factor (Q·f) exibits extremely low due to the inner strain resulting by the occupation of large Ba ions at relatively small A1-sites. However, dielectric constant (ɛr) of this composition show a high value. In this paper, improvement of quality factor (Q·f) by substituting small Sr ions for Ba ions in (Ba1−αSrα)6−3xSm8+2xTi18O54 solid solutions, where x = 0, is reported. In addition, the relationship between crystal structure and microwave dielectric properties is discussed from the viewpoint of structural formula and occupational state of large cations such as Ba, Sr and Sm in A1-sites. 相似文献
106.
ExPosition is a new comprehensive R package providing crisp graphics and implementing multivariate analysis methods based on the singular value decomposition (svd). The core techniques implemented in ExPosition are: principal components analysis, (metric) multidimensional scaling, correspondence analysis, and several of their recent extensions such as barycentric discriminant analyses (e.g., discriminant correspondence analysis), multi-table analyses (e.g.,multiple factor analysis, Statis, and distatis), and non-parametric resampling techniques (e.g., permutation and bootstrap). Several examples highlight the major differences between ExPosition and similar packages. Finally, the future directions of ExPosition are discussed. 相似文献
107.
Chang Yang Chengyin Liu Ning Wu Xiang Wu Yidong Li Zhiying Wang 《Neural computing & applications》2014,25(7-8):1741-1754
Collaboration representation-based classification (CRC) was proposed as an alternative approach to the sparse representation method with similar efficiency. The CRC is essentially a competition scheme for the training samples to compete with each other in representing the test sample, and the training class with the minimum representation residual from the test sample wins the competition in the classification. However, the representation error is usually calculated based on the Euclidean distance between a test sample and the weighted sum of all the same-class samples. This paper exploits alternative methods of calculating the representation error in the CRC methods to reduce the representation residual in a more optimal way, so that the sample classes compete with each other in a closer range to represent the test sample. A large number of face recognition experiments on three face image databases show that the CRC methods with optimized presentation residual achieve better performance than the original CRC, and the maximum improvement in classification accuracy is up to 12 %. 相似文献
108.
《Journal of Process Control》2014,24(8):1301-1310
Energy consumption by heating, ventilation, and air conditioning (HVAC) systems exhibits a clear correlation with electricity prices. The method of economic model predictive control (EMPC) can be used in conjunction with thermal energy storage (TES) to time-shift power consumption away from periods of high demand to periods of low energy cost. Dynamic electricity pricing and weather condition forecasts can be readily incorporated within this methodology. Unfortunately, the receding horizon nature of this control strategy makes it very susceptible to the quality of the forecasts used. To this end, the development and implementation of several forecasting methods will be discussed. Finally, the EMPC performance of these methods will be assessed on a simple building example using active TES. 相似文献
109.
乙醇是一种非常重要的可再生燃料,在本文中,从环境影响和经济效益的角度对不同的原料玉米、纤维素和乙烯生产制乙醇的工艺过程进行了评估,并利用AspenPlus模拟软件中的严格物料和能量平衡模块对典型的生产工艺进行了设计、模拟和优化。基于模拟的结果,提出了定量的环境影响方法一绿色度理论,并通过综合对比文献中报道的数据和模拟数据表明,纤维素制乙醇具有更强的环境影响优势,但在经济效益方面仍需要进一步改进。 相似文献
110.
Assessing the sustainability of non-renewable brackish groundwater in feeding an RO desalination plant in Bahrain 总被引:1,自引:0,他引:1
Waleed K. Al-Zubari 《Desalination》2003,159(3):211-224
The Rus-Umm Er Radhuma aquifer in Bahrain is a non-renewable source of brackish water (8-15 g/L), which forms a lens underlain everywhere with brines of over 100 g/L. Aquifer utilization has started in 1984 to feed a reverse osmosis (RO) desalination plant, with an economic life of 25 years (2010). Future plant upgrade strategy is formulated around boosting the plant production, which will require increasing the we llfield abstraction, in addition to a possible future rehabilitation program to extend the plant life by another 15 years (2025). The limiting factor in expanding the RO plant and its rehabilitation is the future feed water salinity, which have to be assessed before any investments are made to expand the RO plant and commission additional abstraction wells and implement the rehabilitation program. The aquifer management is based on mining a one-time brackish water reserve stored in the aquifer, the main management objective is stated as to sustain the aquifer future availability in feeding the desalination plant with a specified salinity limit of 20 g/L over the economic life of the plant of 25 years (1985-2010), and also over the plant extension period by rehabilitation (2010-2025). The stochastic analysis methodology utilizing conditional simulation is applied to conduct a risk assessment of violating these two pre-specified sustainability constraints under the proposed abstraction increase; and provided a tool to aid the decision-making process in the development and management of the aquifer under large uncertainties. Simulation results indicated that the risk of having the salinity of the wellfi eld produced water to increase due to the proposed increase in the wellfield abstraction to reach 20 g/L over the economic life of the plant (2010) is very small and minimal. However, it is questionable that the feed water salinity will be maintained under the proposed rehabilitation program to extend the plant economic life by another 15 years (2011-2025). For this option, it is recommended that model post-auditing be performed, and new updated predictions should be made as more data of potentiometry. salinity. and hydraulic parameters become available. 相似文献