全文获取类型
收费全文 | 1611篇 |
免费 | 52篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 35篇 |
综合类 | 6篇 |
化学工业 | 398篇 |
金属工艺 | 24篇 |
机械仪表 | 24篇 |
建筑科学 | 78篇 |
矿业工程 | 1篇 |
能源动力 | 36篇 |
轻工业 | 184篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 103篇 |
一般工业技术 | 216篇 |
冶金工业 | 336篇 |
原子能技术 | 12篇 |
自动化技术 | 206篇 |
出版年
2023年 | 17篇 |
2022年 | 19篇 |
2021年 | 36篇 |
2020年 | 25篇 |
2019年 | 18篇 |
2018年 | 25篇 |
2017年 | 23篇 |
2016年 | 32篇 |
2015年 | 34篇 |
2014年 | 45篇 |
2013年 | 62篇 |
2012年 | 87篇 |
2011年 | 77篇 |
2010年 | 55篇 |
2009年 | 62篇 |
2008年 | 54篇 |
2007年 | 54篇 |
2006年 | 46篇 |
2005年 | 38篇 |
2004年 | 38篇 |
2003年 | 31篇 |
2002年 | 28篇 |
2001年 | 20篇 |
2000年 | 26篇 |
1999年 | 31篇 |
1998年 | 55篇 |
1997年 | 33篇 |
1996年 | 34篇 |
1995年 | 31篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 17篇 |
1990年 | 13篇 |
1989年 | 18篇 |
1988年 | 18篇 |
1987年 | 14篇 |
1984年 | 13篇 |
1982年 | 13篇 |
1981年 | 20篇 |
1979年 | 20篇 |
1977年 | 16篇 |
1976年 | 15篇 |
1974年 | 18篇 |
1973年 | 19篇 |
1971年 | 12篇 |
1970年 | 15篇 |
1969年 | 22篇 |
1968年 | 17篇 |
1967年 | 12篇 |
1966年 | 22篇 |
排序方式: 共有1664条查询结果,搜索用时 0 毫秒
11.
The present paper deals with a generalization of the homogeneous multi-server finite-source retrial queue with search for customers in the orbit. The novelty of the investigation is the introduction of balking and impatience for requests who arrive at the service facility with a limited capacity and FIFO queue. Arriving customers may balk, i.e., they either join the queue or go to the orbit. Moreover, the requests are impatient and abandon the buffer after a random time and enter the orbit, too. In case of an empty buffer, each server searches for a customer in the orbit after finishing service. All random variables involved in the model construction are supposed to be exponentially distributed and independent of each other. The primary aim of this analysis is to show the effect of balking, impatience, and buffer size on the steady-state performance measures. Concentrating on the mean response time, several numerical examples are investigated by the help of the MOSEL-2 tool used for creating the model and calculating the stationary characteristics. 相似文献
12.
Jan-Patrick Elsholz Guido de Melo Marc Hermann Michael Weber 《Pervasive and Mobile Computing》2009,5(5):592-605
Ambient displays provide us with information in the background of our awareness. However, as each user has individual wishes and needs of how, which and when information is presented, the acceptance of ambient displays is low.In this paper we introduce an extensible architecture for personalized ambient information.We employ a notification system to extend the capability of a fixture to display more than one variable. Multiple variables can be updated by multiple information providers. Thereby, our architecture covers a broader spectrum of notifications from alarms to ambient information.We evaluate our concept within a dual-task experiment in comparison to preset notifications. The results show a level of self-interruption which is significantly lower than using preset notifications. Therefore our approach outperforms preset notifications and moves ambient displays closer to secondary displays in human–computer interaction. 相似文献
13.
Christophe Kassiotis Adnan Ibrahimbegovic Hermann G. Matthies Bostjan Brank 《Computer Methods in Applied Mechanics and Engineering》2010,199(21-22):1254-1264
An efficient implementation of the operator split procedure for boundary value solution with plastic flow computation is presented for a general form of associated plasticity model. We start with the general form of phenomenological model of plasticity where the yield criterion is not restricted to a simple (quadratic) form, and the elasticity tensor does not have constant entries. We then turn to the multi-scale model of plasticity which employs the fine scale representation of the plastic deformation along with the homogenization procedure for stress computation. We also visit the plasticity model with rate sensitive plastic response where plastic flow computation is carried out at fine scale in time. We proved herein the sufficient and necessary conditions for the proposed operator split procedure to converge, for any such general form of associated plasticity. Moreover, we presented a systematic manner for constructing the main ingredients for the plastic flow computation and the global Newton’s iteration, such as the consistent elastoplastic tangent. 相似文献
14.
15.
Deformation models for image recognition 总被引:2,自引:0,他引:2
Keysers D Deselaers T Gollan C Ney H 《IEEE transactions on pattern analysis and machine intelligence》2007,29(8):1422-1435
We present the application of different nonlinear image deformation models to the task of image recognition. The deformation models are especially suited for local changes as they often occur in the presence of image object variability. We show that, among the discussed models, there is one approach that combines simplicity of implementation, low-computational complexity, and highly competitive performance across various real-world image recognition tasks. We show experimentally that the model performs very well for four different handwritten digit recognition tasks and for the classification of medical images, thus showing high generalization capacity. In particular, an error rate of 0.54 percent on the MNIST benchmark is achieved, as well as the lowest reported error rate, specifically 12.6 percent, in the 2005 international ImageCLEF evaluation of medical image specifically categorization. 相似文献
16.
17.
Inge de Wreede und Hermann Stegemann 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1982,174(3):200-207
Zusammenfassung Die fraktionierte Extraktion mit Na-dodecylsulfat(SDS)-Lösungen ermöglicht die Trennung von Muskel- und Bindegewebs-Protein. In einem zweiten Schritt kann auch Kollagen von Elastin getrennt werden. Muskelprotein löst sich unter Schütteln bei Zimmertemperatur in einer SDS(2%)-ME(1%)-Lösung in einem Boratpuffer pH 9. Zur Lösung des Kollagens sind 100°C, intensives Rühren und eine SDS(8%)-ME(1%)-Lösung in einem Citratpuffer pH 5 notwendig. Das Verfahren wurde an nativem und hitzedenaturiertem Material angewendet. Die Möglichkeit zur Bestimmung des BEFFE-Wertes in Brühwürsten mit dieser Methode wird untersucht und die Anwendung auf andere Fleischprodukte diskutiert.
Benutzte Abkürzungen NPN Nichteiweißstickstoffverbindungen - ATM Acetontrockenmasse - BEFFE bindegewebseiweißfreies Fleischeiweiß - OH-Pro Hydroxyprolin - SDS Natrium(Sodium)-dodecylsulfat - ME 2-Mercapto-äthanol - Tris Tris-(hydroxymethyl)aminomethan - PAGE Polyacrylamid-Gelelektrophorese - Vk Variationskoeffizient - S Standardabweichung - Mittelwert Die Arbeit ist Teil der Dissertation von I. de WreedeWir danken der Deutschen Forschungsgemeinschaft für ihre finanzielle Unterstützung und Herrn Dr. H. H. Heinert, Leiter des Staatl. Veterinär-Untersuchungsamtes Braunschweig, der freundlicherweise die Brühwurstproben zur Verfügung gestellt hat 相似文献
Fractionation of muscle protein, collagen and elastin by extraction with buffers containing dodecylsulfat (SDS)
Summary Dodecylsulfate (SDS) containing buffers were used for stepwise extraction of proteins from muscle and connective tissue. The first step was done at room temperature with borate buffer pH 9 and the muscle proteins were extracted. The second treatment (citrate buffer pH 5 at 100°C) dissolved collagen and left elastin as residue. All extracts were analysed by electrophoresis to identify the proteins and evaluated by a biuret method insensitive to SDS and ME. This method was applied to native and heatdenatured proteins and to Brühwdrste. The possibility of applying this method to the determination of the BEFFE-content is discussed.
Benutzte Abkürzungen NPN Nichteiweißstickstoffverbindungen - ATM Acetontrockenmasse - BEFFE bindegewebseiweißfreies Fleischeiweiß - OH-Pro Hydroxyprolin - SDS Natrium(Sodium)-dodecylsulfat - ME 2-Mercapto-äthanol - Tris Tris-(hydroxymethyl)aminomethan - PAGE Polyacrylamid-Gelelektrophorese - Vk Variationskoeffizient - S Standardabweichung - Mittelwert Die Arbeit ist Teil der Dissertation von I. de WreedeWir danken der Deutschen Forschungsgemeinschaft für ihre finanzielle Unterstützung und Herrn Dr. H. H. Heinert, Leiter des Staatl. Veterinär-Untersuchungsamtes Braunschweig, der freundlicherweise die Brühwurstproben zur Verfügung gestellt hat 相似文献
18.
Applications of sol-gel-processed interphase catalysts 总被引:2,自引:0,他引:2
19.
20.
We propose a compensator-based strategy for design of a track-seeking and track-following control system for a dual-stage servo actuator in hard disk drives. A well-known decoupling structure is employed to disconnect the control of the primary voice coil motor (VCM) actuator from the loop for a secondary high-bandwidth actuator. The compensator is placed in the secondary loop and suitably combined with a saturation nonlinearity in order to obtain actuator signal boundedness. The design procedure consists of four steps: 1) design of an established nonlinear seek-settle-track following controller for the VCM; 2) design of a linear track following controller for the secondary actuator; 3) observer design; and 4) design of a compensator to retain global stability and to improve performance. The proposed control system improves performance of both long-span seeking (proximate-time-optimal controller) and short-span seeking. In addition, it achieves high-bandwidth track following performance. The experimental results show good track-following performance, and short-span/long-span-seeking performance with fast settling time. The overshoot during track seeking can be made negligible for a suitably tuned VCM-actuator control loop. 相似文献