全文获取类型
收费全文 | 1749篇 |
免费 | 37篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 136篇 |
综合类 | 3篇 |
化学工业 | 384篇 |
金属工艺 | 42篇 |
机械仪表 | 68篇 |
建筑科学 | 33篇 |
矿业工程 | 2篇 |
能源动力 | 107篇 |
轻工业 | 135篇 |
水利工程 | 4篇 |
石油天然气 | 6篇 |
无线电 | 154篇 |
一般工业技术 | 290篇 |
冶金工业 | 230篇 |
原子能技术 | 66篇 |
自动化技术 | 130篇 |
出版年
2023年 | 8篇 |
2022年 | 16篇 |
2021年 | 25篇 |
2020年 | 13篇 |
2019年 | 12篇 |
2018年 | 16篇 |
2017年 | 22篇 |
2016年 | 38篇 |
2015年 | 26篇 |
2014年 | 44篇 |
2013年 | 113篇 |
2012年 | 53篇 |
2011年 | 82篇 |
2010年 | 67篇 |
2009年 | 61篇 |
2008年 | 83篇 |
2007年 | 86篇 |
2006年 | 66篇 |
2005年 | 63篇 |
2004年 | 58篇 |
2003年 | 76篇 |
2002年 | 42篇 |
2001年 | 39篇 |
2000年 | 28篇 |
1999年 | 40篇 |
1998年 | 89篇 |
1997年 | 75篇 |
1996年 | 37篇 |
1995年 | 35篇 |
1994年 | 43篇 |
1993年 | 37篇 |
1992年 | 16篇 |
1991年 | 21篇 |
1990年 | 22篇 |
1989年 | 10篇 |
1988年 | 15篇 |
1987年 | 20篇 |
1986年 | 24篇 |
1985年 | 20篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 10篇 |
1980年 | 17篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 17篇 |
1976年 | 12篇 |
1972年 | 3篇 |
1971年 | 3篇 |
排序方式: 共有1790条查询结果,搜索用时 15 毫秒
1.
Kazuo Tsubota Stephen C. Pflugfelder Zuguo Liu Christophe Baudouin Hyo Myung Kim Elisabeth M. Messmer Friedrich Kruse Lingyi Liang Jimena Tatiana Carreno-Galeano Maurizio Rolando Norihiko Yokoi Shigeru Kinoshita Reza Dana 《International journal of molecular sciences》2020,21(23)
Over the past decades, the number of patients with dry eye disease (DED) has increased dramatically. The incidence of DED is higher in Asia than in Europe and North America, suggesting the involvement of cultural or racial factors in DED etiology. Although many definitions of DED have been used, discrepancies exist between the various definitions of dry eye disease (DED) used across the globe. This article presents a clinical consensus on the definition of DED, as formulated in four meetings with global DED experts. The proposed new definition is as follows: “Dry eye is a multifactorial disease characterized by a persistently unstable and/or deficient tear film (TF) causing discomfort and/or visual impairment, accompanied by variable degrees of ocular surface epitheliopathy, inflammation and neurosensory abnormalities.” The key criteria for the diagnosis of DED are unstable TF, inflammation, ocular discomfort and visual impairment. This definition also recommends the assessment of ocular surface epitheliopathy and neurosensory abnormalities in each patient with suspected DED. It is easily applicable in clinical practice and should help practitioners diagnose DED consistently. This consensus definition of DED should also help to guide research and clinical trials that, to date, have been hampered by the lack of an established surrogate endpoint. 相似文献
2.
3.
Graded evolution of anisotropic microstructure during sintering from crystal-oriented powder compact
Shoko Baba Alexandre Maître Nicolas Pradeilles Guy Antou Nobuo Saito Satoshi Tanaka 《International Journal of Applied Ceramic Technology》2020,17(2):677-684
Anisotropic sintering, including shrinkage and grain growth, was examined for c-axis-oriented (Sr,Ca)2NaNb5O15 (SCNN) ceramics, which were prepared by colloidal processing under a magnetic field. In the c-axis-oriented SCNN powder compact, shrinkage and grain growth along the c-axis were higher than those along the a-axis. The anisotropic microstructural development was clearly associated with anisotropic sintering shrinkage. X-ray diffraction, scanning electron microscopy, and energy back scattering diffraction showed that the grain growth of oriented particles by including random grains contribute to the development of the oriented microstructure. Finally, the highly crystal-oriented SCNN ceramics with a densified microstructure were obtained through anisotropic sintering. These results clearly showed the potential to develop a well-defined anisotropic microstructure during sintering by designing and controlling the particle packing structure in a powder compact. 相似文献
4.
It is necessary to determine the accurate reflectance of painted surfaces for the review of paint finishes by computer graphics (CG) before actual painting of the exterior color of automobiles, and for quality control during production and inspection processes. We have optimized a method for measuring reflectance by using a statistical technique. We have found that the reflectance of a painted surface is best measured at an incident angle of 60° and at five aspecular angles of 10°, 18°, 28°, 40°, and 90°. Our method makes it possible to accurately reproduce reflection characteristics of paint finishes containing special flake pigments, such as pearl mica. Also it was proved that our method can apply not only to solid and metallic coatings but to all painted surfaces. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 275–282, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20125 相似文献
5.
6.
7.
Akitoshi Iwata Shinji Ichikawa Mutuwo Tomita Shinji Doki Shigeru Okuma 《Electrical Engineering in Japan》2006,155(3):62-69
This paper presents a novel on‐line parameter identification method for sensorless control of Synchronous Reluctance Motors (SynRMs). Although conventional sensorless control methods based on mathematical models usually need some complex measurements of motor parameters in advance, the proposed identification method does not require them and can be realized on‐line. The proposed method identifies motor parameters under sensorless control, so rotor position and velocity cannot be used to identify these parameters. However, the proposed method does not need rotor position and velocity, and identified parameters are not affected by these estimation errors. The sensorless control using identified motor parameters is realized, and the effectiveness of the proposed method is verified by experimental results. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(3): 62–69, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20258 相似文献
8.
Yasuhiro Kobayashi Toshiyuki Sawa Toshiyuki Furukawa Shigeru Kawamoto 《Electrical Engineering in Japan》2002,138(2):49-58
This paper describes a load dispatch method which minimizes power cost—[fuel cost]/[electric output]—for a power system with thermal plants and energy storage facilities. The proposed method employs fractional programming to convert a minimization problem with fractional objective function to a series of quadratic minimization problems, and semidefinite programming to solve converted problems. The method provides the optimum time‐dependent power output/input and storage level of energy storage facilities as well as time‐dependent power output of thermal plants. The method has been applied to a power system with five thermal plants, two energy storage facilities of various performances, and five load demands. The optimum load scheme of four time mesh points is obtained for the thermal plants and energy storage facilities. The fractional programming successfully converges the optimal scheme through a few iterations. The semidefinite programming deals with a variable matrix of 164 dimensions, and 185 inequality constraints. © 2001 Scripta Technica, Electr Eng Jpn, 138(2): 49–58, 2002 相似文献
9.
A multiplexers available several purposes such as for mobile communications, CATV systems and multimedia systems in future, are propped and trially made by authors. This paper present the results the design concept and experimental results. The design principle was based on the theoretical concept proposed by us 相似文献
10.
T Imai M Baba M Nishimura M Kakizaki S Takagi O Yoshie 《Canadian Metallurgical Quarterly》1997,272(23):15036-15042
Thymus and activation-regulated chemokine (TARC) is a recently identified CC chemokine that is expressed constitutively in thymus and transiently in stimulated peripheral blood mononuclear cells. TARC functions as a selective chemoattractant for T cells that express a class of receptors binding TARC with high affinity and specificity. To identify the receptor for TARC, we produced TARC as a fusion protein with secreted alkaline phosphatase (SEAP) and used it for specific binding. By stably transfecting five orphan receptors and five known CC chemokine receptors (CCR1 to -5) into K562 cells, we found that TARC-SEAP bound selectively to cells expressing CCR4. TARC-SEAP also bound to K562 cells stably expressing CCR4 with a high affinity (Kd = 0.5 nM). Only TARC and not five other CC chemokines (MCP-1 (monocyte chemoattractant protein-1), RANTES (regulated upon activation, normal T cells expressed and secreted), MIP-1alpha (macrophage inflammatory protein-1alpha), MIP-1beta, and LARC (liver and activation-regulated chemokine)) competed with TARC-SEAP for binding to CCR4. TARC but not RANTES or MIP-1alpha induced migration and calcium mobilization in 293/EBNA-1 cells stably expressing CCR4. K562 cells stably expressing CCR4 also responded to TARC in a calcium mobilization assay. Northern blot analysis revealed that CCR4 mRNA was expressed strongly in human T cell lines and peripheral blood T cells but not in B cells, natural killer cells, monocytes, or granulocytes. Taken together, TARC is a specific functional ligand for CCR4, and CCR4 is the specific receptor for TARC selectively expressed on T cells. 相似文献