全文获取类型
收费全文 | 1418篇 |
免费 | 22篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 81篇 |
综合类 | 2篇 |
化学工业 | 419篇 |
金属工艺 | 46篇 |
机械仪表 | 33篇 |
建筑科学 | 21篇 |
能源动力 | 97篇 |
轻工业 | 125篇 |
水利工程 | 9篇 |
石油天然气 | 1篇 |
无线电 | 117篇 |
一般工业技术 | 256篇 |
冶金工业 | 43篇 |
原子能技术 | 45篇 |
自动化技术 | 148篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 20篇 |
2020年 | 13篇 |
2019年 | 23篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 27篇 |
2015年 | 18篇 |
2014年 | 48篇 |
2013年 | 105篇 |
2012年 | 80篇 |
2011年 | 80篇 |
2010年 | 72篇 |
2009年 | 91篇 |
2008年 | 79篇 |
2007年 | 63篇 |
2006年 | 54篇 |
2005年 | 52篇 |
2004年 | 37篇 |
2003年 | 49篇 |
2002年 | 42篇 |
2001年 | 25篇 |
2000年 | 33篇 |
1999年 | 37篇 |
1998年 | 35篇 |
1997年 | 16篇 |
1996年 | 29篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 20篇 |
1992年 | 22篇 |
1991年 | 15篇 |
1990年 | 12篇 |
1989年 | 16篇 |
1988年 | 12篇 |
1987年 | 5篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 13篇 |
1980年 | 16篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1443条查询结果,搜索用时 15 毫秒
51.
Ichiro Imae Shotaro Takayama Daisuke Tokita Yousuke Ooyama Kenji Komaguchi Joji Ohshita Takashi Sugioka Koichi Kanehira Yutaka Harima 《Polymer》2009,50(26):6198-6201
Bis(triethoxysilyl)-substituted oligothiophene with a moderate π-conjugation length was newly synthesized and polymerized to give a polysilsesquioxane network having oligothiophene units dispersed homogeneously without phase separation. The polymer was fixed on glass or ITO substrate by spin-coating and annealing. The resulting film exhibited a high mechanical strength due to the covalent bonding with the substrates, and was electrochemically stable even after 300 redox cycles in electrolyte solution. Chemical oxidation of the polymer films yielded electrically conductive and almost transparent films. 相似文献
52.
Junya Ohyama Yutaka Hitomi Yasuhiro Higuchi Tsunehiro Tanaka 《Topics in Catalysis》2009,52(6-7):852-859
Tetradentate thioacetyl porphyrin ligand (1) was synthesized to protect gold nanoparticles. 1-protected gold nanoparticles were characterized by UV-vis spectroscopy and XPS. Analysis by XPS showed that all of four thioacetyl groups of 1 were dissociated and bound to the surface of gold nanoparticles in thiolate form. The size of 1-protected gold nanoparticles (GN:1) was controlled by thioacetyl group/HAuCl4 molar ratio and approached to 2 nm. Compared with a protecting ligand without porphyrin plane (2) or dodecanethiol, 1 can control the size of gold nanoparticles efficiently probably due to the tetradentate ligation effect. 相似文献
53.
54.
The effect of Zr on reduction of hardness and microstructure in an FS weld of equal channel angular-pressed Al alloy was investigated. Zr addition to Al suppressed dynamic recovery in the thermomechanically affected zone and enabled retention of the high hardness of the ECA-pressed material throughout the weld. 相似文献
55.
Takashi Jin Fumihiko Fujii Yutaka Komai Junji Seki Akitoshi Seiyama Yoshichika Yoshioka 《International journal of molecular sciences》2008,9(10):2044-2061
Fluorescent probes that emit in the near-infrared (NIR, 700–1,300 nm) region are suitable as optical contrast agents for in vivo fluorescence imaging because of low scattering and absorption of the NIR light in tissues. Recently, NIR quantum dots (QDs) have become a new class of fluorescent materials that can be used for in vivo imaging. Compared with traditional organic fluorescent dyes, QDs have several unique advantages such as size- and composition-tunable emission, high brightness, narrow emission bands, large Stokes shifts, and high resistance to photobleaching. In this paper, we report a facile method for the preparation of highly fluorescent, water-soluble glutathione (GSH)-coated NIR QDs for in vivo imaging. GSH-coated NIR QDs (GSH-QDs) were prepared by surface modification of hydrophobic CdSeTe/CdS (core/shell) QDs. The hydrophobic surface of the CdSeTe/CdS QDs was exchanged with GSH in tetrahydrofuran-water. The resulting GSH-QDs were monodisperse particles and stable in PBS (phosphate buffered saline, pH = 7.4). The GSH-QDs (800 nm emission) were highly fluorescent in aqueous solutions (quantum yield = 22% in PBS buffer), and their hydrodynamic diameter was less than 10 nm, which is comparable to the size of proteins. The cellular uptake and viability for the GSH-QDs were examined using HeLa and HEK 293 cells. When the cells were incubated with aqueous solutions of the GSH-QDs (10 nM), the QDs were taken into the cells and distributed in the perinuclear region of both cells. After 12 hrs incubation of 4 nM of GSH-QDs, the viabilities of HeLa and HEK 293 cells were ca. 80 and 50%, respectively. As a biomedical utility of the GSH-QDs, in vivo NIR-fluorescence imaging of a lymph node in a mouse is presented. 相似文献
56.
The tensile properties and fracture behavior of ultrahigh tensile strength PAN-based (T1000GB), ultrahigh modulus pitch-based (K13D) and high ductility pitch-based (XN-05) carbon fibers have been investigated. The statistical distributions of the tensile strength were characterized. The Weibull modulus for the T1000GB, K13D and XN-05 fibers were calculated to be 5.9, 4.2 and 7.9, respectively. The results clearly show that for PAN- and pitch-based carbon fibers, the Weibull modulus decreases with an increase in the tensile modulus and the mean tensile strength. 相似文献
57.
58.
Hiroshi Kihira Takehide Senuma Kiyoshi Nishioka Yutaka Sakata 《Corrosion Science》2005,47(10):2377-2390
Japanese Specification for Highway Bridges [Japan Road Association: Specification for Highway Bridges—I & II, 2002.3] has been revised in 2002, which clearly states that degradation of bridge members, including those of weathering steels, to occur in prolonged period of time must be taken into account at the design stage to realize long term structural durability. To cope with the revised paradigm, SABI chemistry committee in Japan Society of Corrosion Engineers has proposed durable state concept [SABI Chemistry Committee of Japan Society of Corrosion Engineers, in: Proc. 132nd Symposium for Corrosion and Protection, 2001.6.25, p. 3], which is defined as a condition in which corrosion rate of steel is slow enough not to form thick rust [H. Kihira, K. Shiotani, H. Miyuki, T. Nakayama, M. Takemura, Y. Watanabe, Doboku Gakkai Ronbun-shu (J. Japan Soc. Civil Engineers) No. 745/I-65, 2003.10, pp.77-87]. Since corrosiveness of atmosphere differs by location, a corrosion prediction method for both conventional and advanced weathering steels [H. Kihira, A. Usami, K. Tanabe, M. Ito, G. Shigesato, Y. Tomita, T. Kusunoki, T. Tsuzuki, S. Ito, T. Murata, in: Electrochemical Society Proceedings, vol. 99-26, 2000, pp. 127-136] is needed to ensure structural durability for future. Thus, versatile computational scheme for it has been derived through mathematical modeling based upon the durable state concept. 相似文献
59.
Mitsuo Fujimoto Shinji Koga Natsumi Abe Yutaka S. Sato Hiroyuki Kokawa 《Welding International》2013,27(6):403-410
The present study applied friction spot joining (FSJ), which was recently developed as a lap joining technique of Al alloys, to two sheets of Al alloy 6061, 1 mm in thickness, and then examined the microstructural feature in the weld. The weld had the nugget-shaped stir zone around the exit hole of the probe, and the stir zone exhibited the equiaxed grain structure having finer grain size than that of the base material. The crystallographic texture analysis using electron backscattered diffraction method suggested that the material movement occurred along the rotating direction of the welding tool in the wide region including the stir zone. In the periphery of the nugget-shaped stir zone, which was characterized as the region having the finer grain size than that of the stir zone interior, any inclusions and precipitates were not found in the SEM scale. The weld was softened around the weld centre. The softening could be explained by dissolution and/or growth of the strengthening precipitates due to thermal cycle of FSJ. 相似文献
60.
In brain disorders, reactive astrocytes, which are characterized by hypertrophy of the cell body and proliferative properties, are commonly observed. As reactive astrocytes are involved in the pathogenesis of several brain disorders, the control of astrocytic function has been proposed as a therapeutic strategy, and target molecules to effectively control astrocytic functions have been investigated. The production of brain endothelin-1 (ET-1), which increases in brain disorders, is involved in the pathophysiological response of the nervous system. Endothelin B (ETB) receptors are highly expressed in reactive astrocytes and are upregulated by brain injury. Activation of astrocyte ETB receptors promotes the induction of reactive astrocytes. In addition, the production of various astrocyte-derived factors, including neurotrophic factors and vascular permeability regulators, is regulated by ETB receptors. In animal models of Alzheimer’s disease, brain ischemia, neuropathic pain, and traumatic brain injury, ETB-receptor-mediated regulation of astrocytic activation has been reported to improve brain disorders. Therefore, the astrocytic ETB receptor is expected to be a promising drug target to improve several brain disorders. This article reviews the roles of ETB receptors in astrocytic activation and discusses its possible applications in the treatment of brain disorders. 相似文献