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81.
The subsolidus phase diagram of the system Bi2O3–ZnO–Ta2O5 in the region of the cubic pyrochlore phase has been determined at 1050°C. This phase forms a solid solution area that includes the ideal composition P, Bi3Zn2Ta3O14; possible solid solution mechanisms are proposed, supported by density measurements of Zn-deficient solid solutions. The general formula of the solid solutions is Bi3+ y Zn2− x Ta3− y O14− x − y , based on the creation of Zn2+, O2− vacancies in Zn-deficient compositions and a variable Bi/Ta ratio.  相似文献   
82.
We present a visual recognition system for fine-grained visual categorization. The system is composed of a human and a machine working together and combines the complementary strengths of computer vision algorithms and (non-expert) human users. The human users provide two heterogeneous forms of information object part clicks and answers to multiple choice questions. The machine intelligently selects the most informative question to pose to the user in order to identify the object class as quickly as possible. By leveraging computer vision and analyzing the user responses, the overall amount of human effort required, measured in seconds, is minimized. Our formalism shows how to incorporate many different types of computer vision algorithms into a human-in-the-loop framework, including standard multiclass methods, part-based methods, and localized multiclass and attribute methods. We explore our ideas by building a field guide for bird identification. The experimental results demonstrate the strength of combining ignorant humans with poor-sighted machines the hybrid system achieves quick and accurate bird identification on a dataset containing 200 bird species.  相似文献   
83.
Energy conservation in wireless sensor networks: a rule-based approach   总被引:2,自引:1,他引:1  
The research reported in this paper addresses the problem of energy conservation in wireless sensor networks (WSNs). It proposes concepts and techniques to extract environmental information that are useful for controlling sensor operations, in order to enable sensor nodes to conserve their energy, and consequently prolong the network lifetime. These concepts and techniques are consolidated in a generic framework we term CASE: Context Awareness in Sensing Environments framework. CASE targets energy conservation at the network level. A subset framework of CASE, we term CASE Compact, targets energy conservation at the sensor node level. In this paper, we elaborate on these two frameworks, elucidate the requirements for them to operate together within a WSN and evaluate the applications they can be applied to for energy conservation.  相似文献   
84.
Spectroscopic ellipsometry signals used in thin film analysis are dependent on the beam probe size. In this work, we report a technique to determine the beam size that uses the existing detection facilities in a spectroscopic ellipsometry setup without the need to rearrange the optical components. The intensity signal recorded with the technique comprises a coupled boundary diffraction and knife edge wave that can be isolated using nonlinear fitting. This then permitted an accurate measurement of the beam size with the stronger knife edge component. The technique has the added advantage of picking up chromatic aberration in the probing lens which may be a factor in ellipsometry measurement.  相似文献   
85.
Radiation damage is a limiting factor for high resolution structural determination of protein crystals. We have used the median and quartile values of Ne exposures and the structural disordering factor (ΔB) to describe the crystalline disordering due to radiation damage in thin crystals of crotoxin complex embedded in glucose at room and low temperatures and in ice embedded crystals. By approximating the radiation damage to follow first order kinetics, we applied a correction to the diffraction intensities from patterns with high accumulated exposures. We used the structural similarity factor (R) to show that, for some data, the effectiveness of the correction can be as good as those in protein X-ray crystallography.  相似文献   
86.
In this article, we describe the origins, use, and efficacy of a contextualized method for evaluating mobile and ubiquitous computing systems. This technique, which we called paratyping, is based on experience prototyping and event-contingent experience sampling and allows researchers to survey people in real-life situations without the need for costly and sometimes untenable deployment evaluations. We used this tool to probe the perceptions of the conversation partners of users of the Personal Audio Loop, a memory aid with the potential for substantial privacy implications. Based on that experience, we refined and adapted the approach to evaluate SenseCam, a wearable, automatic picture-taking device, across multiple geographic locations. We describe the benefits, challenges, and methodological considerations that emerged during our use of the paratyping method across these two studies. We describe how this method blends some of the benefits of survey-based research with more contextualized methods, focusing on trustworthiness of the method in terms of generating scientific knowledge. In particular, this method is a good fit for studying certain classes of mobile and ubiquitous computing applications but can be applied to many types of applications.  相似文献   
87.
The interchange reaction in blends of poly(ethylene terephthalate) (PET) and poly(m‐xylylene adipamide) (MXD6) has been characterized in terms of changes observed in spectra obtained with a 600‐MHz 1H‐NMR. The selective degradation of PET components in the blends was carried out in the NMR tubes prior to evaluation. Results indicate that there is no chemical reaction between the PET and MXD6 in the absence of sodium p‐toluenesulfonate catalyst. The presence of the catalyst activates the interchange reaction between these two resins. A mathematical method was applied to calculate the degree of randomness of PET‐MXD6 copolymer. In addition, the reaction degree was found to be affected by exposure temperature, time, shear rate, and catalyst concentration. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009  相似文献   
88.
The changes in the structure and optical properties of indium tin oxide (ITO) thin films that were subjected to water electrolysis using an alternating current power source were investigated. X-ray diffraction indicated that the film was reduced to metallic indium after the treatment. Scanning electron microscopy revealed that the film became porous after the treatment. These structural changes had led to a dramatic degradation in the optical properties of ITO. The electrochemical mechanism responsible for the changes was discussed.  相似文献   
89.
90.
Preliminary study on enzymatic hydrolysis process using combination of cellulase and ?? 1-4 glucosidase on treated oil palm empty fruit bunch fibre (EFB) was performed. Crucial trends for parameters such as pH, temperature and substrate loading influencing the enzymatic hydrolysis of the treated EFB fibre were also studied. Results revealed that a combination of both cellulase and ?? 1-4 glucosidase with the ratio of 5:1 hydrolyzed more cellulose from treated EFB fibre and gave highest soluble glucose concentration up to 4 g L−1. The results indicated that as pH and temperature were increased the glucose produced also increased until pH 4.8 and 50 °C; beyond these values the reverse occurred. Glucose produced in the reaction increased with the increment in the substrate loading and maximum glucose concentration (2.7 g L−1) was achieved when 8% (wv−1) treated EFB was used as a substrate.  相似文献   
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