全文获取类型
收费全文 | 6055篇 |
免费 | 264篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 73篇 |
综合类 | 24篇 |
化学工业 | 1202篇 |
金属工艺 | 193篇 |
机械仪表 | 126篇 |
建筑科学 | 216篇 |
矿业工程 | 22篇 |
能源动力 | 116篇 |
轻工业 | 565篇 |
水利工程 | 57篇 |
石油天然气 | 8篇 |
无线电 | 438篇 |
一般工业技术 | 1144篇 |
冶金工业 | 1448篇 |
原子能技术 | 22篇 |
自动化技术 | 667篇 |
出版年
2023年 | 48篇 |
2022年 | 63篇 |
2021年 | 128篇 |
2020年 | 95篇 |
2019年 | 92篇 |
2018年 | 133篇 |
2017年 | 120篇 |
2016年 | 172篇 |
2015年 | 130篇 |
2014年 | 138篇 |
2013年 | 271篇 |
2012年 | 274篇 |
2011年 | 306篇 |
2010年 | 221篇 |
2009年 | 190篇 |
2008年 | 265篇 |
2007年 | 218篇 |
2006年 | 190篇 |
2005年 | 152篇 |
2004年 | 149篇 |
2003年 | 123篇 |
2002年 | 132篇 |
2001年 | 105篇 |
2000年 | 86篇 |
1999年 | 98篇 |
1998年 | 425篇 |
1997年 | 235篇 |
1996年 | 199篇 |
1995年 | 132篇 |
1994年 | 127篇 |
1993年 | 113篇 |
1992年 | 48篇 |
1991年 | 56篇 |
1990年 | 45篇 |
1989年 | 64篇 |
1988年 | 36篇 |
1987年 | 53篇 |
1986年 | 41篇 |
1985年 | 49篇 |
1984年 | 41篇 |
1983年 | 54篇 |
1982年 | 47篇 |
1981年 | 40篇 |
1980年 | 34篇 |
1979年 | 36篇 |
1978年 | 39篇 |
1977年 | 50篇 |
1976年 | 94篇 |
1975年 | 32篇 |
1973年 | 26篇 |
排序方式: 共有6321条查询结果,搜索用时 15 毫秒
81.
Till Schümmer Peter Tandler Joerg M. Haake 《Universal Access in the Information Society》2012,11(3):239-258
Meetings are an important form of interaction in business settings. However, meetings are often not held in a way that makes all participants feel engaged. Meeting support systems try to overcome this obstacle by helping meeting participants in the meeting workflow. This paper takes a complementary approach by distinguishing between different perspectives of good meetings: the peopleware perspective, the generic groupware perspective, and the roomware perspective. It is argued that all these perspectives have to be considered simultaneously when heading toward an ideal meeting system design. The paper presents excerpts of a pattern language that empowers users to improve their meeting. Besides this, the pattern language can be considered as a tool for the designer. After showing, how both groups made use of the patterns, the paper finally presents LivingAgendas, a meeting support system that can accompany the meeting participant through the meeting life cycle. 相似文献
82.
The ionic conductivity of pressed pellets of dehydrated synthetic analcime, sodalite and offretite was determined by a.c. measurements within the range 10 Hz to 10 MHz. The ionic conductivity values of those zeolites exchanged with various monovalent cations were determined by the complex impedance plane method. The conduction activation energies range between 63 and 101 kJ mol–1. Sodium analcime shows the best ionic conductivity, namely 1.8×10–4–1 cm–1 at 400° C. A comparison with the conductivity of other ion-conducting solids was made. 相似文献
83.
Dr.-Ing. K. F. Schäfer Univ.-Prof. Dr.-Ing. J. Verstege 《Electrical Engineering (Archiv fur Elektrotechnik)》1992,76(1):29-32
Übersicht Für die On-line-Netzsicherheitsüberwachung wird eine adaptive Güteindex-Prozedur zur dynamischen Erstellung von Ausfallisten vorgestellt. Mit den bisher bekannten Güteindex-Verfahren konnten aufgrund des Verdeckungseffektes meist nicht alle tatsächlich kritischen Varianten als solche erkannt und deklariert werden. In der neuen Prozedur werden die Ergebnisse der Ausfallsimulationsrechnung der unmittelbaren Systemvergangenheit für die Erstellung der aktuellen Ausfalliste verwendet. Mit einer linearen Korrekturfunktion werden dabei die verdeckungseffektbehaftetenG
2-Werte des Standard-Güteindex-Verfahrens in verbesserte Werte transformiert.
Contingency assessment for power system security analysis
Contents An adaptive procedure for dynamic contingency selection in the on-line security assessment is proposed. Because of the masking effect in conventional performance index algorithms a possibly large number of critical contingencies is misclassified. In the new procedure results of former security checks are used for evaluating the current contingency list. A linear corrective function is applied to transform the standard second orderG-values into improved values.相似文献
84.
W. Minor B. Schönfeld B. Lebech B. Buras W. Dmowski 《Journal of Materials Science》1987,22(11):4144-4152
We have studied the crystallization kinetics of Fe90-x
Si
x
B10 amorphous alloys withx ranging from 7 to 21, by synchrotron X-ray radiation. Using energy- dispersive X-ray diffraction, the kinetics of the different crystalline phases evolving during isothermal annealing were followed. These crystalline phases were identified as precipitation of-Fe(Si) and/or Fe3Si in the amorphous matrix. At a later time or at a higher temperature, Fe2B starts to crystallize (x < 21 ). Only at low iron concentration (x = 21) was the second phase different, namely Fe5SiB2 The hypo- and hyper-eutectic Fe-Si-B glasses were found to crystallize differently. The crystallization processes are discussed in some detail. 相似文献
85.
86.
Mechanical aspects of the rare-earth effect 总被引:8,自引:0,他引:8
In order to gain a better understanding of the reactive-element effect (REE), the improvement of the oxidation behavior of chromia- or alumina-scale-forming alloys by the addition of small amounts of elements with higher affinity to oxygen than the scale-forming element, it is necessary to clearly distinguish between isothermal oxidation and the behavior of the metal/oxide composite system during cooling. An approach is presented based on fracture-mechanical considerations which correlates critical differential strain between scale and substrate, fracture toughness of the metal/scale interface, scale thickness, defect size and interfacial amplitude. This approach allows a quantitative assessment of the REE for scale adhesion, and although the necessary experimental data are yet lacking, it describes the reported REE in a qualitatively correct manner. 相似文献
87.
The mutual interaction of tricalcium silicate (C3S) and β-dicalcium silicate (β-C2S) in their combined hydration was studied. The rate of β-C2S hydration was accelerated significantly in the presence of C3S. The rate of C3S hydration was retarded, but only in the presence of large amounts of β-C2S. The stoichiometric composition and the pore structure of the hydrates formed was altered only unsignificantly when both compound hydrated simultaneously. 相似文献
88.
N. Schönfeldt 《Journal of the American Oil Chemists' Society》1968,45(2):80-82
The course of the lime soap-dispersing action of various surfactants has been examined by use of a titrimetric method. Two
types of dispersants can be distinguished. With the addition of a surfactant of the first type, the concentration of the dispersed
fatty acid increases gradually. If a surfactant of the second type is used, a definite increase of the fatty acid concentration
first occurs after the addition of considerable amounts of the dispersant.
Ethylene oxide adducts and sodium triethylene glycol monolauryl ether sulfate behave like dispersants of the first type whereas
sodium dodecylbenzenesulphonate and sodium lauryl sulfate belong to those of the second type. The dispersing action of both
types of surfactants is discussed. 相似文献
89.
Amanda Jacob 《Reinforced Plastics》2003,47(8):1
This issue contains a preview of the CFA’s annual trade show, which this year takes place in Anaheim, California. Those of you who also attend the JEC Composites Show in Paris will see a vast difference between these two events, not only in cultural terms but also in focus. CFA is an association for US manufacturers and its show places a high emphasis on education and networking. JEC’s slant is to the end-user and it strives to be a showcase for composites technology. Both of these approaches are to the ultimate benefit of the composites industry, but as companies continue to look at ways of spending their money more effectively, show attendance is one area coming under increasing scrutiny. Many have been saying that it is too expensive to attend JEC every year and now a group of major resin suppliers, including DSM, Reichhold, Ashland and Cray Valley, have taken the step of staying away from next year’s show (see page 64). This will surely dent the show’s profits and it will be interesting to see how the organisers, as well as other exhibitors, will respond to this development. 相似文献
90.
Jochen Schütz 《Journal of scientific computing》2014,60(2):438-456
We apply the concept of asymptotic preserving schemes (SIAM J Sci Comput 21:441–454, 1999) to the linearized \(p\) -system and discretize the resulting elliptic equation using standard continuous Finite Elements instead of Finite Differences. The fully discrete method is analyzed with respect to consistency, and we compare it numerically with more traditional methods such as Implicit Euler’s method. 相似文献