全文获取类型
收费全文 | 1351篇 |
免费 | 44篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 74篇 |
综合类 | 3篇 |
化学工业 | 371篇 |
金属工艺 | 30篇 |
机械仪表 | 33篇 |
建筑科学 | 27篇 |
矿业工程 | 1篇 |
能源动力 | 74篇 |
轻工业 | 99篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 85篇 |
一般工业技术 | 257篇 |
冶金工业 | 203篇 |
原子能技术 | 32篇 |
自动化技术 | 106篇 |
出版年
2023年 | 7篇 |
2022年 | 21篇 |
2021年 | 31篇 |
2020年 | 9篇 |
2019年 | 13篇 |
2018年 | 28篇 |
2017年 | 26篇 |
2016年 | 31篇 |
2015年 | 28篇 |
2014年 | 19篇 |
2013年 | 69篇 |
2012年 | 42篇 |
2011年 | 66篇 |
2010年 | 46篇 |
2009年 | 65篇 |
2008年 | 57篇 |
2007年 | 64篇 |
2006年 | 52篇 |
2005年 | 40篇 |
2004年 | 40篇 |
2003年 | 34篇 |
2002年 | 27篇 |
2001年 | 25篇 |
2000年 | 37篇 |
1999年 | 30篇 |
1998年 | 70篇 |
1997年 | 46篇 |
1996年 | 43篇 |
1995年 | 19篇 |
1994年 | 29篇 |
1993年 | 26篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 18篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 17篇 |
1986年 | 6篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 16篇 |
1975年 | 9篇 |
1973年 | 11篇 |
排序方式: 共有1398条查询结果,搜索用时 0 毫秒
981.
Yasuo Hirose Hirokazu Matsuda Go Matsubara Masaki Hojo Fumihide Inamura 《Composites Part A》2012,43(8):1318-1325
A new type of crack arrester concept, named the splice-type crack arrester, was invented and applied to a core–core splice in a foam core sandwich panel in order to suppress interfacial crack growth. An analytical evaluation of this crack arrester including parametric studies was carried out. It was confirmed by finite element (FE) analysis that interfacial crack propagation was suppressed by a decrease in the energy release rate at the crack tip under constant loading owing to the splice-type crack arrester as the crack tip approached the edge of the arrester. Through this study, it was revealed that the leading edge of the splice-type crack arrester, its shape and material, have strong effects on the crack suppression capability. 相似文献
982.
Hiromu Ambai Yusuke Nishizuka Yuichi Sano Naoki Uchida Shizuka Iijima Hideaki Shiwaku 《Journal of Nuclear Science and Technology》2019,56(2):193-200
During the accident that occurred at the Fukushima Daiichi nuclear power plant, a large volume of seawater was introduced as coolant into the storage pools for spent nuclear fuel. If this fuel is reprocessed, some components of seawater will be mixed with the nitric acid solution containing metal ions in the reprocessing process where stainless steels are used as structural material. In this study, we investigated the effect of seawater components in high active liquid waste (HAW) containing nitric acid and metal ions as fission products on the corrosion behavior of SUS316L stainless steel.
Corrosion tests were conducted in surrogate HAW containing artificial seawater (ASW). Intergranular corrosion was observed in the HAW with ASW, where Ru increased the corrosion potential to the transpassive region. An increase in the amount of ASW led to a decrease in the corrosion rate and suppression of intergranular corrosion. Interactions between Ru ions and seawater components, such as chloride ions, were indicated by the results of extended X-ray absorption fine structure spectroscopy and cyclic voltammetry analyses of the solution containing ASW and HAW. 相似文献
983.
Xiaqin Wang Kensuke Naka Meifang Zhu Hidekatsu Kuroda Hideaki Itoh Yoshiki Chujo 《Journal of Inorganic and Organometallic Polymers and Materials》2007,17(2):447-457
Successive deposition of octa(3-aminopropyl)octasilsesquioxane octahydrochloride and gold nanoparticles coated with carboxylate
groups (Au–COO−) on glass substrates alternately under mild basic conditions led to systematic buildup of a gold colloidal multilayer. The
driving force of the self-assembly was electrostatic interaction between ammonium cations of octa(3-aminopropyl)octasilsesquioxane
octahydrochloride and carboxylate anions on Au–COO−. A linear increase of surface plasmon resonance of Au–COO− with the deposited bilayers indicated the multilayer manipulation was reproducible. Porous nanocomposites were accomplished
by precipitation of octa(3-aminopropyl)octasilsesquioxane octahydrochloride modified polystyrene (PS) latex particles and
Au–COO− followed by removal of the PS particles via tetrahydrofuran (THF) extraction. Porous nanocomposite films were obtained by
layer-by-layer (LBL) self-assembly of the octa(3-aminopropyl)octasilsesquioxane octahydrochloride modified PS latex particles
and Au–COO− followed by removal of the PS particles via THF extraction.
Dedicated to Professor Christopher W. Allen for his advances in inorganic ring and polymer chemistry. 相似文献
984.
Salicylaldehyde Suppresses IgE-Mediated Activation of Mast Cells and Ameliorates Anaphylaxis in Mice
Tsubasa Ashikari Masakazu Hachisu Kazuki Nagata Daisuke Ando Yuki Iizuka Naoto Ito Kandai Ito Yuki Ikeda Hiroki Matsubara Takuya Yashiro Kazumi Kasakura Chiharu Nishiyama 《International journal of molecular sciences》2022,23(15)
Mast cells (MCs) play key roles in IgE-mediated immunoresponses, including in the protection against parasitic infections and the onset and/or symptoms of allergic diseases. IgE-mediated activation induces MCs to release mediators, including histamine and leukotriene, as an early response, and to produce cytokines as a late phase response. Attempts have been made to identify novel antiallergic compounds from natural materials such as Chinese medicines and food ingredients. We herein screened approximately 60 compounds and identified salicylaldehyde, an aromatic aldehyde isolated from plant essential oils, as an inhibitor of the IgE-mediated activation of MCs. A degranulation assay, flow cytometric analyses, and enzyme-linked immunosorbent assays revealed that salicylaldehyde inhibited the IgE-mediated degranulation and cytokine expression of bone-marrow-derived MCs (BMMCs). The salicylaldehyde treatment reduced the surface expression level of FcεRI, the high affinity receptor for IgE, on BMMCs, and suppressed the IgE-induced phosphorylation of tyrosine residues in intercellular proteins, possibly Lyn, Syk, and Fyn, in BMMCs. We also examined the effects of salicylaldehyde in vivo using passive anaphylaxis mouse models and found that salicylaldehyde administration significantly enhanced the recovery of a reduced body temperature due to systemic anaphylaxis and markedly suppressed ear swelling, footpad swelling, and vascular permeability in cutaneous anaphylaxis. 相似文献
985.
The nitride capacities in CaO-TiO2-TiO1.5 slags, and nitrogen distribution ratio between these slags and liquid Cu (LN = (mass-% N)/[mass-% N]) were measured by a gas-slag-metal equilibration technique, using a Mo crucible in the temperature range of 1823 to 1923 K under controlled partial pressures of oxygen and nitrogen . The values for , (mass-% Ti3+)/(mass-% Ti4+) ratio, and solubility of TiN in CaO-TiO2-TiO1.5 slags were obtained as a function of slag composition (XCaO = 0.24 ~ 0.39) and temperature. Activity coefficients of TiN were evaluated from the values for activity coefficients of Ti in liquid Cu which were calculated from the results of TiN saturation experiments. 相似文献
986.
Viewpoint image generation for head tracking 3D display using multi‐camera and approximate depth information 下载免费PDF全文
Munekazu Date Hideaki Takada Akira Kojima 《Journal of the Society for Information Display》2015,23(8):339-346
A simple and high image quality method for viewpoint image synthesis from multi‐camera images for a stereoscopic 3D display using head tracking is proposed. In this method, slices of images for depth layers are made using approximate depth information, the slices are linearly blended corresponding to the distance between the viewpoint and cameras at each layer, and the layers are overlaid from the perspective of viewpoint. Because the linear blending automatically compensates for depth error because of the visual effects of depth‐fused 3D (DFD), the resulting image is natural to observer's perception. Smooth motion parallax of wide depth range objects induced by viewpoint movement for left‐and‐right and front‐and‐back directions is achieved using multi‐camera images and approximate depth information. Because the calculation algorithm is very simple, it is suitable for real time 3D display applications. 相似文献
987.
N Matsubara OA Hietala SK Gilmour KY Yum S Litwin P Watts Brennan O'Brien 《Canadian Metallurgical Quarterly》1995,1(6):665-671
Several studies have documented increased expression of ornithine decarboxylase (ODC) in neoplastic colorectal tissue versus normal-appearing colonic mucosa. The present study was undertaken to determine whether there is an association between the degree of overexpression of ODC in colorectal carcinomas and survival in a series of 74 patients. A high level of tumor ODC expression was found to be significantly associated with greater survival in our patient series. Patients with tumor ODC activities greater than the median and especially in the highest quartile experienced a more favorable outcome than those patients with ODC values below the median or in the lowest quartile (P = 0.03 and 0.02, respectively). The presence of a GTP-activatable isoform of ODC was also significantly associated with a favorable prognosis but only in tumors of the right colon (P = 0.01). There was no association found between ODC activity and tumor grade, tumor size, or patient age, sex, or race. Our results demonstrate that high levels of ODC expression (and presence of a GTP-activatable isoform for right-sided colon tumors) predict a favorable prognosis in human colorectal carcinoma. Knowledge of a patient's ODC status at the time of surgery may be useful in decisions regarding adjuvant therapy. Understanding the mechanism(s) involved should lead to new therapeutic approaches for advanced colorectal carcinoma. 相似文献
988.
Mei Yang Yan Huang Jaime Kim Meejeong Lee Tatsuya Suda Matsubara Daisuke 《Computer Communications》2005,28(18):2034-2046
This paper proposes a new QoS framework, called the On-Demand QoS Path framework (ODP). It provides end-to-end QoS guarantees to individual flows with minimal overhead, while keeping the scalability characteristic of DiffServ. ODP exercises per-flow admission control and end-to-end bandwidth reservation at the edge of the network and only differentiates service types in the core of the network. In addition, to adapt to dynamically changing traffic load, ODP monitors the bandwidth utilization of the network and performs dynamic bandwidth reconfiguration in the network core based on the monitored bandwidth utilization. Through extensive simulations, the performance of ODP is investigated and compared with that of IntServ and DiffServ frameworks. The simulation results clearly showed that ODP provides end-to-end QoS guarantees to individual flows, which DiffServ can not provide, with much less overhead than IntServ. 相似文献
989.
Effects of electrolyte addition on photocatalytic activity of (Ga1−xZnx)(N1−xOx) modified with either Rh2−yCryO3 or RuO2 nanoparticles as cocatalysts for overall water splitting under visible light (λ > 400 nm) are investigated. The cocatalyst Rh2−yCryO3 is confirmed to selectively promote the photoreduction of H+, while RuO2 functions as both H2 evolution sites and as efficient O2 evolution sites. The activity of Rh2−yCryO3-loaded (Ga1−xZnx)(N1−xOx) is found to be suppressed in the presence of Cl−, which undergoes oxidation by photogenerated holes in the valence band of (Ga1−xZnx)(N1−xOx). Alkaline- and alkaline earth-metal cations in the reactant solution compensate the negative effect of Cl− to a certain extent depending on the metal cation employed. Among the electrolytes examined, the addition of an appropriate amount of NaCl or A2SO4 (A = Li, Na, or K) to the reactant solution without pH control is found to increase activity by up to 75% compared to the case without additives. Direct splitting of seawater to produce H2 and O2 is also demonstrated using Rh2−yCryO3-loaded (Ga1−xZnx)(N1−xOx) catalyst under visible light. 相似文献
990.
A new method of evaluating the workability of a tube in cold pilgering has been studied on the basis of material deformability and the effects of process conditions. A circumferential compression test of a tube is confirmed to be an effective evaluation method for deformability. The critical reduction in height upon crack initiation in the compression test is also found to be a good measure of material deformability. Systematic cold pilgering tests and the numerical analysis of cold pilgering are conducted. As a result, the ratio of radial strain to circumferential strain during pilgering is a good indicator of process conditions, and a common mechanism of inner fissure formation during pilgering in stainless steel, titanium alloy, and zirconium alloy is proposed. Finally, a suitable expression for workability is obtained by considering material deformability and the effects of pilgering conditions. These findings will assist the selection of appropriate pilgering conditions to prevent the formation of fissures on the inner surface of a tube. 相似文献