全文获取类型
收费全文 | 1523篇 |
免费 | 93篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
综合类 | 2篇 |
化学工业 | 324篇 |
金属工艺 | 38篇 |
机械仪表 | 40篇 |
建筑科学 | 42篇 |
矿业工程 | 4篇 |
能源动力 | 65篇 |
轻工业 | 103篇 |
水利工程 | 13篇 |
石油天然气 | 4篇 |
无线电 | 135篇 |
一般工业技术 | 326篇 |
冶金工业 | 215篇 |
原子能技术 | 15篇 |
自动化技术 | 278篇 |
出版年
2023年 | 21篇 |
2022年 | 34篇 |
2021年 | 54篇 |
2020年 | 48篇 |
2019年 | 36篇 |
2018年 | 48篇 |
2017年 | 51篇 |
2016年 | 58篇 |
2015年 | 42篇 |
2014年 | 77篇 |
2013年 | 92篇 |
2012年 | 97篇 |
2011年 | 129篇 |
2010年 | 79篇 |
2009年 | 70篇 |
2008年 | 72篇 |
2007年 | 70篇 |
2006年 | 49篇 |
2005年 | 48篇 |
2004年 | 37篇 |
2003年 | 26篇 |
2002年 | 17篇 |
2001年 | 14篇 |
2000年 | 22篇 |
1999年 | 29篇 |
1998年 | 48篇 |
1997年 | 29篇 |
1996年 | 38篇 |
1995年 | 14篇 |
1994年 | 17篇 |
1993年 | 16篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 14篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1983年 | 7篇 |
1981年 | 3篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1957年 | 2篇 |
排序方式: 共有1617条查询结果,搜索用时 125 毫秒
81.
Carole Guillaume Jeremy Pinte Nathalie Gontard Emmanuelle Gastaldi 《Food research international (Ottawa, Ont.)》2010,43(5):1395-1401
The objective of the present work was to understand how the structural, surface, water vapour and gas barrier properties of wheat gluten (WG) coated paper could be influenced by the features of paper. For this purpose, a surface treated paper (TP) and an untreated paper (UTP) were compared. Penetration of WG-coating into the bulk of paper was more pronounced in UTP than TP. This led to the formation of a significant junction zone resulting in an interpenetrated structure for WG–UTP, suggesting a composite-like structure, while a bi-layer one was obtained for WG–TP. Differences in WG penetration were related to the hydrophilicity, roughness and porosity of the paper used. Even though the extent of penetration did not greatly affect the surface properties (water and oil resistance), the transfer properties (water vapour, O2 and CO2) of WG-coated papers were significantly improved when WG-coating highly penetrated: while the WG–TP behaved as a micro-perforated material, the WG–UTP behaved as WG-film. 相似文献
82.
Nielsen Guillaume Janin Amelie Coudert Lucie Blais Jean Francois Mercier Guy 《Mine Water and the Environment》2018,37(1):42-55
Mine Water and the Environment - Passive treatment is a promising, green technology that is increasingly being used for mine drainage treatment. However, several challenges remain concerning its... 相似文献
83.
The increase in computational capabilities has made time-domain methods applicable for long-range sound propagation modelling. However, such approaches remain very demanding in terms of computational resources. Most current computers are supplied with a powerful device which is still little exploited: the graphics processing unit (GPU). The paper describes an implementation of a transmission line matrix model which allows parallel calculations on heterogeneous systems. A voxelization algorithm used to generate the computational domain is presented. A splitting process is also expounded which makes feasible performing huge domains simulations by accurately dividing the computational domain into subdomains. Each subdomain is enlarged by introducing extra cells containing neighbours subdomains data in order to run several computational iterations on a graphic device without data exchange with the system memory. The influence of the ghost layer depth and the speeding up of computation time with GPU are then illustrated in a realistic built-up area. 相似文献
84.
Alain Ruffion Marian Devonec Denis Champetier Myriam Decaussin-Petrucci Claire Rodriguez-Lafrasse Philippe Paparel Paul Perrin Virginie Vlaeminck-Guillem 《International journal of molecular sciences》2013,14(9):17767-17780
While now recognized as an aid to predict repeat prostate biopsy outcome, the urinary PCA3 (prostate cancer gene 3) test has also been recently advocated to predict initial biopsy results. The objective is to evaluate the performance of the PCA3 test in predicting results of initial prostate biopsies and to determine whether its incorporation into specific nomograms reinforces its diagnostic value. A prospective study included 601 consecutive patients addressed for initial prostate biopsy. The PCA3 test was performed before ≥12-core initial prostate biopsy, along with standard risk factor assessment. Diagnostic performance of the PCA3 test was evaluated. The three available nomograms (Hansen’s and Chun’s nomograms, as well as the updated Prostate Cancer Prevention Trial risk calculator; PCPT) were applied to the cohort, and their predictive accuracies were assessed in terms of biopsy outcome: the presence of any prostate cancer (PCa) and high-grade prostate cancer (HGPCa). The PCA3 score provided significant predictive accuracy. While the PCPT risk calculator appeared less accurate; both Chun’s and Hansen’s nomograms provided good calibration and high net benefit on decision curve analyses. When applying nomogram-derived PCa probability thresholds ≤30%, ≤6% of HGPCa would have been missed, while avoiding up to 48% of unnecessary biopsies. The urinary PCA3 test and PCA3-incorporating nomograms can be considered as reliable tools to aid in the initial biopsy decision. 相似文献
85.
Xianqin Meng Guillaume Gomard Ounsi El Daif Emmanuel Drouard Regis Orobtchouk Anne Kaminski Alain Fave Mustapha Lemiti Alexei Abramov Pere Roca i Cabarrocas Christian Seassal 《Solar Energy Materials & Solar Cells》2011
In this paper, we present the integration of an absorbing photonic crystal within a thin-film photovoltaic solar cell. Optical simulations performed on a complete solar cell revealed that patterning the hydrogenated amorphous silicon active layer as a 2D photonic crystal membrane enabled to increase its integrated absorption by 28 % between 300 and 720 nm, comparing to a similar but unpatterned stack. In order to fabricate such promising cells, we developed a high throughput process based on holographic lithography and reactive ion etching. The influences of the parameters taking part in those processes on the obtained patterns are discussed. Optical measurements performed on the resulting “photonized” solar cell structures underline the regularity of the 2D pattern and a significant absorption increase above 550 nm, similarly to what is observed on the simulated absorption spectra. Moreover, our patterned cells are found to be robust with regards to the angle of incidence of the light. 相似文献
86.
Guillaume Pichavant Daniel Beysens Denis Chatain Daniel Communal Clément Lorin Alain Mailfert 《Microgravity science and technology》2011,23(2):129-133
A ground based facility (OLGA), providing magnetic compensation of gravity in oxygen, has been developed. A 2-T superconducting
magnetic solenoid is used to create the required magnetic field. A novel electrical supply permits to quickly vary the magnetic
field, leading to rapid variation of the acceleration forces applied to oxygen. These variations can be made from overcompensation
of gravity (−0.5g) to zero gravity or from zero gravity to reduced gravity (0.4g) with a time constant of 340 ms. This time is typical of the cutoff or reignition of spacecraft engines. Preliminary results
on the transient flows induced by these acceleration variations in a reservoir filled with liquid and gaseous oxygen are presented. 相似文献
87.
Olivier Terraz Guillaume Guimberteau Stéphane Mérillou Dimitri Plemenos Djamchid Ghazanfarpour 《The Visual computer》2009,25(2):165-180
In this paper an extension of L-systems is proposed, based on three-dimensional (3D) generalized maps that allow an easier
control of the internal structure of 3D objects. A first and original application of this extension is also proposed: wood
modelling by growth simulation. Numerous other applications of our work are possible, in the area of computer graphics, as
well as in botanical science. 相似文献
88.
Helen Reveron Laurent Blanchard Yann Vitupier Emmanuelle Rivière Guillaume Bonnefont Gilbert Fantozzi 《Journal of the European Ceramic Society》2011,31(4):645-652
Many space systems such as satellite mirrors and their supporting structures require to be made from very low-thermal expansion materials combining both high hydrostability and relatively high mechanical properties. In this study, we have applied the “composite concept” in order to explore the possibility of fabricating near zero thermal expansion silicon nitride based ceramics. Consequently, a negative thermal expansion material belonged to the lithium aluminosilicate family (LAS powder crystallized under de β-eucryptite structure) was introduced in an alpha-silicon nitride fine powder (5 and 20 vol% of LAS) and the resulting composite system was sintered by Spark Plasma Sintering (SPS) at 1400 and 1500 °C. In the case of 20 vol% LAS compositions, relatively well-densified ceramics (94.4% of the theoretical density) were produced without adding any further sintering additive. The addition of yttria and alumina oxides allowed enhancing the densification level up to 98.2% (20 vol% LAS compositions) or from 62.3% up to 96.7% of the theoretical density in 5 vol% LAS materials. Nevertheless, it was impossible to full consolidate silicon nitride/LAS composite ceramics at temperatures lower than the temperature at which β-eucryptite melts, even by using SPS technology. Moreover, because of the relatively low temperatures involved in SPS, the α to β-Si3N4 transformation was avoided, resulting in microstructures composed of fine equiaxed α-Si3N4 grains (<200 nm) and of a glassy phase. Even if the effect of having a very large negative thermal expansion material was lost during the sintering step (because of the β-eucryptite melting), ceramics containing only 20 vol% of LAS-based phase exhibited very interesting values as regards of mechanical properties (strength, hardness, toughness, and Young's modulus), thermal conductivity and thermal expansion coefficient. We discuss in this work why we are so interested in developing dense silicon nitride/LAS ceramics sintered without any further additive addition, even though β-eucryptite is melted during the process and the transformation to the β phase is avoided. 相似文献
89.
Amédée Djemai Etienne Balan Guillaume Morin Giancarlo Hernandez Jean Claude Labbe Jean Pierre Muller 《Journal of the American Ceramic Society》2001,84(5):1017-1024
Kaolinites with various degrees of structural order and iron content were heated and subsequently analyzed via electron paramagnetic resonance. Iron was present in two different states in the heated materials, either as dilute structural Fe3+ ions or in concentrated Fe3+ phases. During metakaolinization, the environment of dilute Fe3+ ions changed, following modifications of the Al3+ coordination, and the Fe3+ concentration increased. With the breakdown of metakaolinite, the diffusion of Fe3+ ions induced their exsolution in superparamagnetic iron-rich domains (Fe3+ clusters in γ-Al2 O3 and/or Fe3+ oxide nanophases), which produced a decrease in the dilute Fe3+ concentration. The subsequent breakdown of γ-Al2 O3 and the formation of mullite made the dilute Fe3+ concentration increase again, because of the incorporation of Fe3+ ions in the mullite structure. 相似文献
90.
Mathias Dietrich Guillaume Delaittre James P. Blinco Andrew J. Inglis Michael Bruns Christopher Barner‐Kowollik 《Advanced functional materials》2012,22(2):304-312
The nitrile imine‐mediated tetrazole‐ene cycloaddition reaction (NITEC) is introduced as a powerful and versatile conjugation tool to covalently ligate macromolecules onto variable (bio)surfaces. The NITEC approach is initiated by UV irradiation and proceeds rapidly at ambient temperature yielding a highly fluorescent linkage. Initially, the formation of block copolymers by the NITEC methodology is studied to evidence its efficacy as a macromolecular conjugation tool. The grafting of polymers onto inorganic (silicon) and bioorganic (cellulose) surfaces is subsequently carried out employing the optimized reaction conditions obtained from the macromolecular ligation experiments and evidenced by surface characterization techniques, including X‐ray photoelectron spectroscopy and FT‐IR microscopy. In addition, the patterned immobilization of variable polymer chains onto profluorescent cellulose is achieved through a simple masking process during the irradiation. 相似文献