全文获取类型
收费全文 | 5844篇 |
免费 | 184篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 21篇 |
综合类 | 4篇 |
化学工业 | 653篇 |
金属工艺 | 124篇 |
机械仪表 | 161篇 |
建筑科学 | 56篇 |
矿业工程 | 1篇 |
能源动力 | 141篇 |
轻工业 | 220篇 |
水利工程 | 21篇 |
石油天然气 | 5篇 |
武器工业 | 2篇 |
无线电 | 347篇 |
一般工业技术 | 490篇 |
冶金工业 | 3452篇 |
原子能技术 | 54篇 |
自动化技术 | 281篇 |
出版年
2024年 | 3篇 |
2023年 | 34篇 |
2022年 | 62篇 |
2021年 | 98篇 |
2020年 | 62篇 |
2019年 | 63篇 |
2018年 | 85篇 |
2017年 | 85篇 |
2016年 | 85篇 |
2015年 | 80篇 |
2014年 | 119篇 |
2013年 | 169篇 |
2012年 | 215篇 |
2011年 | 249篇 |
2010年 | 160篇 |
2009年 | 182篇 |
2008年 | 128篇 |
2007年 | 88篇 |
2006年 | 101篇 |
2005年 | 92篇 |
2004年 | 72篇 |
2003年 | 67篇 |
2002年 | 52篇 |
2001年 | 52篇 |
2000年 | 54篇 |
1999年 | 143篇 |
1998年 | 1057篇 |
1997年 | 621篇 |
1996年 | 386篇 |
1995年 | 251篇 |
1994年 | 189篇 |
1993年 | 222篇 |
1992年 | 35篇 |
1991年 | 69篇 |
1990年 | 53篇 |
1989年 | 68篇 |
1988年 | 63篇 |
1987年 | 46篇 |
1986年 | 35篇 |
1985年 | 37篇 |
1983年 | 7篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 19篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 94篇 |
1976年 | 130篇 |
1975年 | 5篇 |
1955年 | 1篇 |
排序方式: 共有6033条查询结果,搜索用时 15 毫秒
141.
Bi-objective scheduling for reentrant hybrid flow shop using Pareto genetic algorithm 总被引:1,自引:0,他引:1
Hang-Min Cho Suk-Joo Bae Jungwuk Kim In-Jae Jeong 《Computers & Industrial Engineering》2011,61(3):529-541
This paper deals with a scheduling problem for reentrant hybrid flowshop with serial stages where each stage consists of identical parallel machines. In a reentrant flowshop, a job may revisit any stage several times. Local-search based Pareto genetic algorithms with Minkowski distance-based crossover operator is proposed to approximate the Pareto optimal solutions for the minimization of makespan and total tardiness in a reentrant hybrid flowshop. The Pareto genetic algorithms are compared with existing multi-objective genetic algorithm, NSGA-II in terms of the convergence to optimal solution, the diversity of solution and the dominance of solution. Experimental results show that the proposed crossover operator and local search are effective and the proposed algorithm outperforms NSGA-II by statistical analysis. 相似文献
142.
The notions of $(\overline{\in}, \overline{\in} \vee \overline{\hbox{q}})The notions of ([`( ? )],[`( ? )] ú[`q])(\overline{\in}, \overline{\in} \vee \overline{\hbox{q}})-fuzzy p-ideals and fuzzy p-ideals with thresholds related to soft set theory are discussed. Relations between ([`( ? )],[`( ? )] ú[`q])(\overline{\in}, \overline{\in} \vee \overline{\hbox{q}})-fuzzy ideals and ([`( ? )],[`( ? )] ú[`q])(\overline{\in}, \overline{\in} \vee \overline{\hbox{q}})-fuzzy p-ideals are investigated. Characterizations of an ([`( ? )],[`( ? )] ú[`q])(\overline{\in}, \overline{\in} \vee \overline{\hbox{q}})-fuzzy p-ideal and a fuzzy p-ideal with thresholds are displayed. Implication-based fuzzy p-ideals are discussed. 相似文献
143.
Bae Jun Young 《Information Sciences》2009,179(24):4284-1770
The idea of (faithful) intuitionistic fuzzy transformation semigroup, intuitionistic admissible relation, and intuitionistic (strong) homomorphism are introduced and their basic properties are examined. 相似文献
144.
Sanghoon Park Roxana Shabani Mark Schumacher Yoon-Seoung Kim Young Min Bae Kyeong-Hee Lee Hyoung Jin Cho 《Microsystem Technologies》2016,22(8):2077-2085
Miniaturized on-chip blood separators have a great value for point-of-care diagnosis. In our work, a combined design strategy—microfiltration, sedimentation in a retarded flow, and wetting contrast—was taken to overcome the known limitations of on-chip blood separators. Our microfluidic chip consists of a polydimethylsiloxane micropillar array and an etched glass with microchannel branches. The red blood cells are significantly slowed and gradually settled down due to micropillars and enlarged dimension of a chamber. An etched glass microchannel allows the extraction of blood plasma exclusively due to the capillary effect. The fabricated microfluidic device can separate blood plasma from a whole blood sample without any external driving force or dilution. The measured plasma separation efficiency was close to 100 % from human whole blood. Autonomous on-chip separation and collection of blood plasma was demonstrated. 相似文献
145.
Geonyup Lim Kyoung-Su Park No-Cheol Park Young-Pil Park Yonghyun Lee Young Bae Chang Cheol-soon Kim 《Microsystem Technologies》2016,22(6):1315-1324
Recently, the number of disks in hard disk drives has increased, and the gap between the slider and disk has decreased. These changes make the contact between the ramp and disk easily. External shock and ramp–disk contact can cause change in disk curvature. Such a change in disk curvature affects the air bearing pressure between the slider and disk. However, disk curvature has not been considered in the previous research. Thus, in this study, we investigated the influence of disk curvature on slider dynamics. Disk curvature was calculated from a transient shock analysis, and was then applied to slider dynamic analysis. As a result, disk curvature reduced the shock performance, by decreasing the minimum flying height and increasing the pitch and roll angle of the slider. 相似文献
146.
This paper provides simple and effective linear matrix inequality (LMI) characterizations for the stability and stabilization conditions of discrete-time Takagi–Sugeno (T–S) fuzzy systems. To do this, more general classes of non-parallel distributed compensation (non-PDC) control laws and non-quadratic Lyapunov functions are presented. Unlike the conventional non-quadratic approaches using only current-time normalized fuzzy weighting functions, we consider not only the current-time fuzzy weighting functions but also the l-step-past (l?0) and one-step-ahead ones when constructing the control laws and Lyapunov functions. Consequently, by introducing additional decision variables, it can be shown that the proposed conditions include the existing ones found in the literature as particular cases. Examples are given to demonstrate the effectiveness of the approaches. 相似文献
147.
Petri net is used widely to analyze and model various systems formally. Recently, many Petri nets mania devote their efforts to enhancing and extending the expressive power of Petri nets. One such effort is to extend Petri nets with object-oriented concepts. An object-oriented paradigm provides excellent concepts to model real-world problems. Object-oriented concepts allow us to build software systems easily, intuitively, and naturally. Although several high-level Petri nets with the concept of objects are suggested, these nets do not fully support the object-oriented concepts. In this paper, we propose a hierarchical object-oriented Petri net (HOONet). The formal syntax and semantics of HOONet are explained in detail. HOONet supports a wide range of object-oriented features including abstract, encapsulated and modularized objects, object interaction by message passing, inheritance, and ploymorphism. HOONet also supports a variety of modeling and analysis mechanisms such as incremental modeling of evolving systems, unfolding the HOONet to lower level Petri net, and incremental reachability analysis for HOONet models. We demonstrate the usefulness of HOONet by applying it to modeling and analysis with an example. 相似文献
148.
Adaptive Output Feedback Control of Flexible-Joint Robots Using Neural Networks: Dynamic Surface Design Approach 总被引:1,自引:0,他引:1
Sung Jin Yoo Jin Bae Park Yoon Ho Choi 《Neural Networks, IEEE Transactions on》2008,19(10):1712-1726
In this paper, we propose a new robust output feedback control approach for flexible-joint electrically driven (FJED) robots via the observer dynamic surface design technique. The proposed method only requires position measurements of the FJED robots. To estimate the link and actuator velocity information of the FJED robots with model uncertainties, we develop an adaptive observer using self-recurrent wavelet neural networks (SRWNNs). The SRWNNs are used to approximate model uncertainties in both robot (link) dynamics and actuator dynamics, and all their weights are trained online. Based on the designed observer, the link position tracking controller using the estimated states is induced from the dynamic surface design procedure. Therefore, the proposed controller can be designed more simply than the observer backstepping controller. From the Lyapunov stability analysis, it is shown that all signals in a closed-loop adaptive system are uniformly ultimately bounded. Finally, the simulation results on a three-link FJED robot are presented to validate the good position tracking performance and robustness of the proposed control system against payload uncertainties and external disturbances. 相似文献
149.
Indicating that CBMC does not satisfy the monotonic property in terms of the number of interactions, Xu and Zhou proposed an augmented definition of CBMC by adopting cut set instead of glue methods. The augmented CBMC clearly satisfies the monotonic property. However, CBMC is designed to overcome the problem with respect to the number of interactions and, therefore, focuses on the interaction pattern, especially, member connectivity. Consequently, it does not make sense to mention the monotonic property of CBMC with respect to interaction number. Moreover, the notion of glue methods allows several interpretations on the design quality of a class. However, that meaningful interpretation is not possible for the augmented definition due to the removal of the notion of glue methods. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
150.
P Le Guellec S Dumas GE Volle E Pidoux MS Moukhtar F Treilhou-Lahille 《Canadian Metallurgical Quarterly》1993,41(3):389-395
We report here an efficient and rapid method for the specific detection of calcitonin in tumor C-cells of medullary thyroid carcinoma (MTC). This occasionally aggressive tumor arises from the endocrine thyroid C-cells. Its principal marker is calcitonin, the predominant C-cell secretion, which is detected in patients and in our animal model by radioimmunoassay of the plasma, as well as by immunohistochemistry of thyroid tissues. Although calcitonin is easily detectable in normal C-cells, its content is greatly reduced in tumor cells owing to the disappearance of the secretory granules that store the mature peptide. This finding suggests cell dedifferentiation correlated with an increasing aggressivity of the tumor. We therefore developed a rapid detection of calcitonin mRNA by in situ hybridization on routine paraffin sections, using a synthetic oligodeoxyribonucleotide probe labeled with digoxigenin-dUTP. The reaction was detected with an anti-digoxigenin antibody conjugated with alkaline phosphatase, and the enzyme catalyzed the appearance of a dark blue color. The signal was exclusively restricted to the normal, hyperplastic, and tumor C-cells. It was specific, as increasing concentrations of the unlabeled oligonucleotide led to progressive disappearance of the reaction. Its sensitivity was slightly diminished as compared with corresponding frozen sections, but the intensity of the signal was quite acceptable. High levels of calcitonin mRNA were found in all normal and hyperplastic C-cells. They were increased in most of the tumor MTC cells, which did not correlate with the amount of intracellular peptide stores but explained the abnormally high basal levels of circulating calcitonin of the tumor-bearing rats. ISH is therefore of greater value than ICC for an early anatomopathological detection of this tumor. Our data show that the tumor cells are not "dedifferentiated." They only lack the granular compartment storing the mature peptide before exocytosis, but CT biosynthesis and the rest of the secretory process seem to be complete. Our results suggest that factors expressed in malignant C-cells affect basic cell mechanisms involved in the storage of the mature calcitonin, rather than the expression of the CALC gene. 相似文献