全文获取类型
收费全文 | 1514篇 |
免费 | 60篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 64篇 |
综合类 | 7篇 |
化学工业 | 341篇 |
金属工艺 | 28篇 |
机械仪表 | 38篇 |
建筑科学 | 28篇 |
矿业工程 | 2篇 |
能源动力 | 52篇 |
轻工业 | 170篇 |
水利工程 | 16篇 |
石油天然气 | 11篇 |
无线电 | 156篇 |
一般工业技术 | 235篇 |
冶金工业 | 307篇 |
原子能技术 | 9篇 |
自动化技术 | 116篇 |
出版年
2023年 | 12篇 |
2022年 | 26篇 |
2021年 | 44篇 |
2020年 | 29篇 |
2019年 | 47篇 |
2018年 | 39篇 |
2017年 | 46篇 |
2016年 | 42篇 |
2015年 | 26篇 |
2014年 | 45篇 |
2013年 | 76篇 |
2012年 | 53篇 |
2011年 | 80篇 |
2010年 | 48篇 |
2009年 | 48篇 |
2008年 | 61篇 |
2007年 | 45篇 |
2006年 | 41篇 |
2005年 | 47篇 |
2004年 | 40篇 |
2003年 | 44篇 |
2002年 | 33篇 |
2001年 | 19篇 |
2000年 | 26篇 |
1999年 | 23篇 |
1998年 | 119篇 |
1997年 | 69篇 |
1996年 | 60篇 |
1995年 | 26篇 |
1994年 | 26篇 |
1993年 | 37篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 13篇 |
1987年 | 8篇 |
1986年 | 9篇 |
1985年 | 18篇 |
1984年 | 9篇 |
1982年 | 12篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 3篇 |
1978年 | 11篇 |
1977年 | 6篇 |
1976年 | 17篇 |
1975年 | 7篇 |
1973年 | 4篇 |
1965年 | 2篇 |
排序方式: 共有1580条查询结果,搜索用时 15 毫秒
961.
Indium oxide cubic crystals were prepared by using hexamethylenetetramine and indium chloride without the addition of any structure directing agents. The chemical route followed in the present work was a modified hydrothermal synthesis. The average crystallite size of the prepared cubes was found to be 40 nm. A blue emission at 418 nm was observed at room temperature when the sample was excited with a 380 nm Xenon lamp. This emission due to oxygen vacancies made the material suitable for gas sensing applications. The synthesized material was made as a composite film with polyvinyl alcohol which was more flexible than the films prepared on glass substrates. This flexible film was used as a sensing element and tested with ethanol vapours at room temperature. The film showed fast response as well as recovery to ethanol vapours with a sensor response of about 1.4 for 100 ppm of the gas. 相似文献
962.
引言
人防工程不仅要为战时功能服务,体现其战备效益,而且平时要开放,目前随着人防工程的增多,其内空气品质问题已经引起业内人士的重视,尤其是平时用作商业、娱乐及旅馆的人防工程内部空气品质更是我们所关注的焦点性问题。本文着重对人防工程的设计的探讨。 相似文献
963.
964.
Charge transport processes at the interface of n-GaAs (100) with an aqueous HCl solution are studied by electrochemical impedance spectroscopy. It is found that when open-circuit
potential and anodic potentials are applied to the semiconductor the impedance spectra contain two capacitive semicircles
corresponding to the capacitances of the space charge layer and surface states. In the case of open-circuit potential, semiconductor
band bending at the interface with the solution is about 0.7 eV and the density of occupied surface states in the dark and
under daylight conditions is 1.6 and 2.8 × 1012 cm2 eV−1, respectively. When cathode potentials are applied to GaAs, hydrogen evolution begins at the semiconductor/electrolyte interface
and an additional inductive loop appears in the impedance spectra. At the same time, the density of occupied surface states
increases considerably both due to a straightening of the semiconductor bands and to the appearance of As-H bonds. Thus, charge
transport through the n-GaAs (100)/aqueous HCl solution interface is always mediated by semiconductor surface states. 相似文献
965.
966.
Takizawa Yoichi Sumikawa Kosei Watanabe Kyohei Masuda Takahiro Yumoto Manabu Kanai Yuta Otagiri Yoshiharu Horita Zenji 《Metallurgical and Materials Transactions A》2018,49(5):1830-1840
Metallurgical and Materials Transactions A - This study updates a process of high-pressure sliding (HPS) recently developed as a severe plastic deformation process under high pressure for grain... 相似文献
967.
M. E. Cagiao F. J. Baltá Calleja F. Spieckermann S. Scholtyssek M. F. Mina M. A. H. Bhuiyan 《应用聚合物科学杂志》2012,124(4):3147-3153
Composites of isotactic polypropylene with various contents of white clay or titanium dioxide TiO2 were prepared by extrusion molding. The extruded composites were melt‐pressed at two different temperatures, and, thereafter, either slowly cooled, or quenched to room temperatures. It is shown that the structure of all the samples, as revealed by wide‐angle X‐ray scattering and small‐angle X‐ray scattering (SAXS), depends on the processing conditions. The lack of SAXS maxima in the composites suggests that the presence of the microadditives hinders the stacking of iPP lamellae. Furthermore, the microindentation hardness H in the slowly cooled composites is influenced by the type and amount of the filler used. However, in the quenched samples H depends only on the amount of the filler used, and not on its type. In case of the quenched iPP/clay composites, the relationship between H and the Young's modulus E is found to be H/E ≈ 0.12, in good agreement with Struik's theoretical predictions of σe ≈ E/30, in consonance with results previously obtained for a series of polyethylene samples with different morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
968.
Luiz Saramago Mariana Franceschi Carlos Logullo Aoi Masuda Itabajara da Silva Vaz Jr. Sandra Estrazulas Farias Jorge Moraes 《International journal of molecular sciences》2012,13(10):13118-13133
In the present work, we produced two monoclonal antibodies (BrBm37 and BrBm38) and tested their action against the triosephosphate isomerase of Rhipicephalus (Boophilus) microplus (RmTIM). These antibodies recognize epitopes on both the native and recombinant forms of the protein. rRmTIM inhibition by BrBm37 was up to 85% whereas that of BrBrm38 was 98%, depending on the antibody-enzyme ratio. RmTIM activity was lower in ovarian, gut, and fat body tissue extracts treated with BrBm37 or BrBm38 mAbs. The proliferation of the embryonic tick cell line (BME26) was inhibited by BrBm37 and BrBm38 mAbs. In summary, the results reveal that it is possible to interfere with the RmTIM function using antibodies, even in intact cells. 相似文献
969.
Yoko Hanada Shoichi Masuda Motoyuki Iijima Hidehiro Kamiya 《Advanced Powder Technology》2013,24(5):844-851
To clarify the role of polymer dispersants at the carbon black (CB) nanoparticle/liquid interface, the adsorbed structure of the dispersants and the interactions between particle surfaces was evaluated using colloid probe AFM. As it is difficult to prepare stable spherical granules consisting of CB nanoparticles with diameters on the scale of several microns, for a colloidal probe by spray drying and sintering, CB nanoparticles were uniformly coated on the surface of spherical resin particles using a physical composing process. In order to establish the mechanism of action of the CB polymer dispersant by using the prepared colloid probe, polyethyleneimine (PEI) and PEI functionalized with a hydrophobic toluoyl group (T-PEI) were compared. It was found that on the adsorption of T-PEI, the viscosity of the aqueous CB suspension and the size of the aggregates were remarkably decreased in acidic conditions. Although the amounts of PEI and T-PEI adsorbed onto the CB were almost the same, a larger repulsive interaction was observed in the case of the T-PEI. CB nanoparticle dispersion was promoted by the increase in steric repulsion due to the structure of the adsorbed T-PEI. 相似文献
970.
Andreas Bircher Mina Kamel Kostas Alexis Helen Oleynikova Roland Siegwart 《Autonomous Robots》2018,42(2):291-306
Within this paper a new path planning algorithm for autonomous robotic exploration and inspection is presented. The proposed method plans online in a receding horizon fashion by sampling possible future configurations in a geometric random tree. The choice of the objective function enables the planning for either the exploration of unknown volume or inspection of a given surface manifold in both known and unknown volume. Application to rotorcraft Micro Aerial Vehicles is presented, although planning for other types of robotic platforms is possible, even in the absence of a boundary value solver and subject to nonholonomic constraints. Furthermore, the method allows the integration of a wide variety of sensor models. The presented analysis of computational complexity and thorough simulations-based evaluation indicate good scaling properties with respect to the scenario complexity. Feasibility and practical applicability are demonstrated in real-life experimental test cases with full on-board computation. 相似文献