全文获取类型
收费全文 | 1119篇 |
免费 | 44篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 32篇 |
综合类 | 8篇 |
化学工业 | 357篇 |
金属工艺 | 20篇 |
机械仪表 | 29篇 |
建筑科学 | 59篇 |
矿业工程 | 6篇 |
能源动力 | 21篇 |
轻工业 | 79篇 |
水利工程 | 6篇 |
无线电 | 93篇 |
一般工业技术 | 162篇 |
冶金工业 | 77篇 |
原子能技术 | 5篇 |
自动化技术 | 211篇 |
出版年
2023年 | 17篇 |
2022年 | 23篇 |
2021年 | 29篇 |
2020年 | 22篇 |
2019年 | 21篇 |
2018年 | 25篇 |
2017年 | 16篇 |
2016年 | 32篇 |
2015年 | 39篇 |
2014年 | 37篇 |
2013年 | 49篇 |
2012年 | 61篇 |
2011年 | 69篇 |
2010年 | 65篇 |
2009年 | 53篇 |
2008年 | 59篇 |
2007年 | 52篇 |
2006年 | 60篇 |
2005年 | 44篇 |
2004年 | 29篇 |
2003年 | 23篇 |
2002年 | 30篇 |
2001年 | 17篇 |
2000年 | 20篇 |
1999年 | 16篇 |
1998年 | 22篇 |
1997年 | 25篇 |
1996年 | 17篇 |
1995年 | 24篇 |
1994年 | 20篇 |
1993年 | 20篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 5篇 |
1987年 | 7篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 6篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1972年 | 4篇 |
1971年 | 3篇 |
排序方式: 共有1165条查询结果,搜索用时 31 毫秒
101.
Mathias Herrmann Sören Höhn Axel Bales 《Journal of the European Ceramic Society》2012,32(7):1313-1319
The reproducible sintering and microstructure formation of α- and α/β-Sialons is a precondition for the production of such materials with reproducible properties.The Rietveld method was used for quantitative analysis of the phase composition and the kinetics of incorporation of the rare earth into the α-Sialon structure. The analysis showed that in the early stages of sintering more rare earth cations were incorporated into the grains than would be expected from the equilibrium conditions. This was observed for all investigated rare earths (Y, Nd and Yb) with different ionic radii. The consequences for sintering and microstructure formation are the fast disappearing of the transient liquid and the formation of polytypes. The use of excess of rare earth in comparison to the stoichiometric Sialon composition results in a stable residual liquid. It allows reproducible densification, anisotropic grain growth and materials with high fracture toughness. 相似文献
102.
Axel Griesche Eusebio Solórzano Katrin Beyer Thomas Kannengiesser 《International Journal of Hydrogen Energy》2013
Neutron radiography (NR) is compared with the commonly used carrier gas hot extraction (CGHE) technique. We performed isothermal hydrogen effusion experiments at 623 K to study the mass transport kinetics. The investigated material was technical iron. The quantification of the hydrogen mass flow is done for NR by using concentration standards. The temporal hydrogen concentration evolution in the sample coincides well for both methods, i.e. NR and CGHE, and is in good agreement with literature. The advantages of the NR method are the non-destructive nature of measuring and the in-situ determination of hydrogen concentrations with high spatial and temporal resolution. Remaining hydrogen inside the sample can be identified directly by the NR method. 相似文献
103.
104.
Precipitation kinetics of Nb(C,N) in microalloyed steels is crucial for the achievement of favoured steel properties. Therefore, numerous experimental studies have been performed in the past and various theoretical models have been developed to describe Nb(C,N) precipitation. However, the experimental data is sometimes contradictory and even the thermodynamic data for NbC solubility in austenite have a large scatter. In this paper, experimental results on the Nb(C,N) and NbV(C,N) precipitation kinetics in deformed and undeformed austenite are reviewed. Based on these data and with the precipitation kinetics module of the software package MatCalc, computer simulations are performed. The predicted interfacial energy of precipitates is adjusted to match the observed kinetics. A comparison between experimental information and simulation, i.e. time ‐ temperature ‐ precipitation (TTP) diagrams, is drawn and discussed. The results of the computer simulations using modified interfacial energies are in good agreement with the experiments. 相似文献
105.
Axel G. Rossberg ?ke Br?nnstr?m Ulf Dieckmann 《Journal of the Royal Society Interface》2010,7(53):1735-1743
A question central to modelling and, ultimately, managing food webs concerns the dimensionality of trophic niche space, that is, the number of independent traits relevant for determining consumer–resource links. Food-web topologies can often be interpreted by assuming resource traits to be specified by points along a line and each consumer''s diet to be given by resources contained in an interval on this line. This phenomenon, called intervality, has been known for 30 years and is widely acknowledged to indicate that trophic niche space is close to one-dimensional. We show that the degrees of intervality observed in nature can be reproduced in arbitrary-dimensional trophic niche spaces, provided that the processes of evolutionary diversification and adaptation are taken into account. Contrary to expectations, intervality is least pronounced at intermediate dimensions and steadily improves towards lower- and higher-dimensional trophic niche spaces. 相似文献
106.
107.
A filtration system for keeping the analytics free of particles is usually required for inline characterization of particle‐laden process gasses. Additionally gas pumps may be needed for overcoming the pressure drop of filter element and filter cake. Consecutive reactions of process gas and filter cake may be disadvantageous for the quality of the gas analysis. A new probing apparatus is presented for extraction of particle‐free gas samples from particle‐laden process gasses. The probe combines the functionalities of a gas pump and a particle separator. While the gas is transported from process to analysis, particles are separated according to the principle of air classification. 相似文献
108.
Axel Schumacher Christian Olschinka 《Structural and Multidisciplinary Optimization》2008,35(3):263-272
The optimization of structures subject to highly nonlinear behavior, particularly crash structures, requires observance of
all design-significant scatterings. This paper presents a time-saving method to generate structures satisfying robust design
demands. A vital aspect of robust design from the aircraft industries’ point of view is the consideration of fail-safe approaches
accounting for possible structural failure from previous loading or manufacturing inaccuracies. Additional structural elements
are utilized to prevent (after failure occurred) the structure from deforming out of bounds. This paper presents an approach
on how to include this in the robust design process. 相似文献
109.
110.