全文获取类型
收费全文 | 1267篇 |
免费 | 26篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 39篇 |
综合类 | 1篇 |
化学工业 | 181篇 |
金属工艺 | 20篇 |
机械仪表 | 24篇 |
建筑科学 | 24篇 |
矿业工程 | 2篇 |
能源动力 | 14篇 |
轻工业 | 119篇 |
水利工程 | 8篇 |
石油天然气 | 6篇 |
武器工业 | 2篇 |
无线电 | 237篇 |
一般工业技术 | 167篇 |
冶金工业 | 284篇 |
原子能技术 | 3篇 |
自动化技术 | 163篇 |
出版年
2022年 | 10篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 12篇 |
2016年 | 15篇 |
2015年 | 18篇 |
2014年 | 25篇 |
2013年 | 37篇 |
2012年 | 37篇 |
2011年 | 33篇 |
2010年 | 16篇 |
2009年 | 29篇 |
2008年 | 44篇 |
2007年 | 54篇 |
2006年 | 36篇 |
2005年 | 45篇 |
2004年 | 31篇 |
2003年 | 46篇 |
2002年 | 44篇 |
2001年 | 43篇 |
2000年 | 34篇 |
1999年 | 42篇 |
1998年 | 126篇 |
1997年 | 72篇 |
1996年 | 45篇 |
1995年 | 42篇 |
1994年 | 37篇 |
1993年 | 40篇 |
1992年 | 27篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 17篇 |
1984年 | 12篇 |
1983年 | 12篇 |
1982年 | 9篇 |
1981年 | 8篇 |
1980年 | 14篇 |
1979年 | 5篇 |
1977年 | 10篇 |
1976年 | 16篇 |
1975年 | 8篇 |
1974年 | 6篇 |
1973年 | 6篇 |
1972年 | 5篇 |
排序方式: 共有1294条查询结果,搜索用时 0 毫秒
41.
The purpose of the current study was to examine in detail the association between witnessing domestic violence (DV) and long-term psychological adjustment. Important limitations of past research were addressed, including controlling for several associated risk factors. Special attention was paid to whether the perpetrator of the violence was the maternal or paternal figure, as well as to whether the witness to the violence was male or female. Participants completed measures examining DV witnessed, direct child abuse experienced, and current psychopathology. Following screening for physical and sexual abuse, a sample of 351 individuals was selected. Four groups of participants were compared. Results indicated that individuals who had witnessed either physical DV or major psychological DV had higher levels of psychopathology than individuals who reported witnessing minor psychological DV or controls. After controlling for direct psychological abuse experienced, witnessing DV remained a significant predictor of psychopathology for males but not for females. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
42.
A screw dislocation network at the low-angle SrTiO3/Nb:SrTiO3 twist grain boundary has been analyzed by annular dark field (ADF) imaging and spatially resolved electron energy loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM). The cores of one set of dislocations running parallel to the beam direction appear dark in the ADF STEM images. EELS on the dislocation core reveals a reduced Sr/Ti ratio compared to the bulk suggesting Sr-deficient cores. The second set of dislocations, orthogonal to the latter, is imaged by its strain field using low-angle annular dark field (LAADF) imaging. Multislice image simulations suggest channeling of the electron probe on the atomic columns for small tilts, theta < 1 degree, where the Sr columns act as beam guides. Only for larger tilts is the channeling effect strongly reduced and the fringe contrast approaches the value predicted by a purely incoherent imaging model. Ti-L(2,3) EELS across the dislocation core shows an asymmetry between the EELS and the ADF signal which cannot be explained by the geometry or beam broadening. This asymmetry might be explained by an effective nonlocal potential representing inelastic scattering in EELS. 相似文献
43.
Finding the intersection of two convex polyhedra 总被引:1,自引:0,他引:1
Given two convex polyhedra in three-dimensional space, we develop an algorithm to (i) test whether their intersection is empty, and (ii) if so to find a separating plane, while (iii) if not to find a point in the intersection and explicitly construct their intersection polyhedron. The algorithm runs in timeO (nlogn), where n is the sum of the numbers of vertices of the two polyhedra. The part of the algorithm concerned with (iii) (constructing the intersection) is based upon the fact that if a point in the intersection is known, then the entire intersection is obtained from the convex hull of suitable geometric duals of the two polyhedra taken with respect to this point. 相似文献
44.
Smail Meziani Messaouda Kaci Muriel Jacquot Jordane Jasniewski Pablo Ribotta Jean-Marc Muller Mohamed Ghoul Stéphane Desobry 《Journal of food engineering》2012
The frozen bakery market has grown significantly in developed countries over the past decade. 相似文献
45.
46.
Doubly fed induction generator systems for wind turbines 总被引:6,自引:0,他引:6
This article shows that adjustable speed generators for wind turbines are necessary when output power becomes higher than 1 MW. The doubly fed induction generator (DFIG) system presented in this article offers many advantages to reduce cost and has the potential to be built economically at power levels above 1.5 MW, e.g., for off-shore applications. A dynamic model of the DFIG was derived to develop a vector controller to decouple dynamically active and reactive power control. Simulations show excellent response of the DFIG independent of speed. Measurements obtained from 1.5 MW units currently in operation confirm the theoretical results 相似文献
47.
K. Donadel C.R. Rambo W.S. Chacon M.D.M. Innocentini R.C. Catapan D. Muller A.A.M. Oliveira A.P.N. Oliveira 《Ceramics International》2012
In this work catalytic fibrous filters were produced through two distinct processing routes from natural amorphous silica fibers (NASF) and Ni(NO3)2 solution (wet route) and NiO (dry route) as catalyst precursors. The Ni–SiO2 fibers were characterized for X-ray powder diffraction, scanning electron microscope, particle size distribution, specific surface area, nickel contents, porosity, tortuosity, permeability, compressive strength, degree of dispersion, filtration and gas conversion efficiency. Morphological characterization revealed that Ni from wet route was distributed over the silica fibers with significantly lower particle size than the Ni produced through the dry route. Both methods led to a homogeneous distribution of Ni. The catalytic fibrous filter obtained from the dry route showed higher conversion efficiency for both propylene and propane, especially at high temperatures, due to the higher degree of dispersion of Ni particles over the NASF surfaces. 相似文献
48.
Clotilde Muller Sandrine Muller Aicha Sissoko Alexandre Klein Bernadette Faller Francois Chantrel 《Hemodialysis international. International Symposium on Home Hemodialysis》2012,16(4):556-558
Lanthanum therapy is an efficient therapy of hyperphosphoremia by chelating phosphore in the digestive tract. Lanthanum is a silvery white metallic element that belongs to group 3 of the periodic table. This drug is lightly absorbed and has low water solubility. It should be borne in mind that abdominal X‐rays of patients taking lanthanum carbonate may have a radio‐opaque appearance typical of imaging agents. This characteristic is suggested to confirm adherence of the patient by doing an abdominal X‐ray. We describe in our case a particular good compliant patient with slow digestive transit, which ends by pseudo‐occlusion. 相似文献
49.
F. Seyler V. Chaplot F. Muller C. E. P. Cerri M. Bernoux V. Ballester 《International journal of remote sensing》2013,34(23):4985-5004
Attempts to map vegetation types, especially pasture, from satellite sensor data in tropical and sub-tropical regions very often have limited success. This study analyses the accuracy of two classifications of Landsat Thematic Mapper (TM), with the aim of distinguishing the pastures from other vegetation classes in a meso-scale basin (12 400 km 2, Piracicaba basin, Brazil). The initial classification is based on non-supervised clustering of the images. The delimited classes are interpreted and merged by comparison with standard spectra from NASA. The second classification is a parallelepiped partition based on the merged clusters issued from the first one. The two classifications are compared by validation with 287 random field observations selected within the whole catchment. The results are discussed, analysing the spectral behaviour variability of the pasture class. 相似文献
50.
Jérôme Rondin Michel Bouquey René Muller Christophe A. Serra Grégory Martin Philippe Sonntag 《Polymer Engineering and Science》2014,54(6):1444-1457
Polypropylene and ethylene‐propylene‐diene terpolymer (PP/EPDM) blends were melt compounded in a new mixing device, designed in our laboratory under the trademark of RMX®, which predominantly generates elongational flows. Dispersion of the EPDM minor phase in PP was carried out in both RMX® and in an internal mixer (Haake Rheomix 600) at equivalent specific mixing energies and the resultant morphologies obtained by SEM were analyzed and compared. A better dispersive mixing efficiency of the RMX® mixer, i.e., lower Dn and Dv of the dispersed EPDM phase was observed. The impact of elongational flow was more pronounced for blends having a high viscosity ratio p, indicating an enhanced droplet break‐up mechanism, which was attributed to the combination of high shear rates inside the mixing element and important elongational flows in the convergent/divergent zones. The morphology of the blends was correlated with their linear viscoelastic properties by using the Palierne model. Very good agreement was found for the PP/EPDM 80/20 blends but for higher EPDM content, the Palierne model failed to describe the rheological behavior, which was attributed to percolation of the minor phase with increasing the concentration. Higher elasticity at low frequencies was observed for blends processed in the RMX®, which was attributed to a higher generated interfacial area. POLYM. ENG. SCI., 54:1444–1457, 2014. © 2013 Society of Plastics Engineers 相似文献