全文获取类型
收费全文 | 1105篇 |
免费 | 42篇 |
国内免费 | 11篇 |
专业分类
电工技术 | 9篇 |
综合类 | 3篇 |
化学工业 | 100篇 |
金属工艺 | 11篇 |
机械仪表 | 40篇 |
建筑科学 | 47篇 |
能源动力 | 20篇 |
轻工业 | 73篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 163篇 |
一般工业技术 | 186篇 |
冶金工业 | 372篇 |
原子能技术 | 4篇 |
自动化技术 | 121篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 7篇 |
2020年 | 7篇 |
2019年 | 4篇 |
2018年 | 18篇 |
2017年 | 13篇 |
2016年 | 14篇 |
2015年 | 12篇 |
2014年 | 25篇 |
2013年 | 55篇 |
2012年 | 30篇 |
2011年 | 40篇 |
2010年 | 33篇 |
2009年 | 33篇 |
2008年 | 33篇 |
2007年 | 45篇 |
2006年 | 42篇 |
2005年 | 22篇 |
2004年 | 38篇 |
2003年 | 36篇 |
2002年 | 35篇 |
2001年 | 24篇 |
2000年 | 21篇 |
1999年 | 37篇 |
1998年 | 141篇 |
1997年 | 84篇 |
1996年 | 53篇 |
1995年 | 32篇 |
1994年 | 33篇 |
1993年 | 25篇 |
1992年 | 18篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 12篇 |
1973年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有1158条查询结果,搜索用时 15 毫秒
101.
The paper studies the restoration of colour-quantised images. Restoration of colour-quantised images is rarely addressed in the literature, and direct applications of existing restoration techniques are generally inadequate to deal with this problem. The authors propose a POCS-based restoration algorithm specific to colour-quantised images, which makes a good use of the available colour palette to derive useful a priori information for restoration. The proposed restoration algorithm is shown to be capable of improving the quality of a colour-quantised image to a certain extent. 相似文献
102.
HK Atrash LT Strauss JS Kendrick FE Skjeldestad YW Ahn 《Canadian Metallurgical Quarterly》1997,89(4):512-518
The present study was conducted to elucidate the effects of tirilazad mesylate (U-74006F), a potent inhibitor of lipid peroxidation, on vessel diameter, capillary perfusion, and contractile function of rat cremaster muscle during a 90-minute reperfusion period that followed 4 hours of warm ischemia. Two groups of 32 animals were treated with either 3 mg/kg U-74006F or the vehicle (citrate buffer) alone 30 minutes before ischemia, 90 minutes after ischemia, and immediately before reperfusion. With use of intravital videomicroscopy, the internal luminal diameters of preselected vessels were measured prior to ischemia and during reperfusion. The area that filled with fluorescein was determined at 15-minute intervals for as long as 90 minutes of reperfusion, and contractile function was examined in vitro in an organ bath at that point. In the U-74006F group, after 90 minutes of reperfusion the vessel diameters returned completely to baseline and the diameters of all three categories of vessels at every time point from 10 to 90 minutes of reperfusion had significantly more rapid recovery than the controls. Although some evidence of more rapid fluorescence was noted in the U-74006F group, the two groups did not differ significantly at any time period of reperfusion. In response to tetanic stimulation, the muscles treated with U-74006F had a significantly greater contractile force at all stimulation frequencies than the control muscles. Our findings indicate that pretreatment with U-74006F can effectively decrease the rise of vascular resistance and preserve the contractile function of skeletal muscle during early reperfusion, thereby attenuating ischemia-reperfusion injury. 相似文献
103.
MA Nalesnik AS Rao H Furukawa S Pham A Zeevi JJ Fung G Klein HA Gritsch E Elder TL Whiteside TE Starzl 《Canadian Metallurgical Quarterly》1997,63(9):1200-1205
Lymphoreticular malignancies, collectively called posttransplant lymphoproliferative disorders (PTLD), eventually develop in 2-5% of organ transplant recipients. They frequently undergo regression when immunosuppression is reduced or stopped. This feature has been associated with a previous or de novo Epstein-Barr virus (EBV) infection. We herein describe immunotherapy with autologous lymphokine-activated killer (LAK) cells in seven patients with PTLD (four EBV-positive patients and three EBV-negative patients). Autologous peripheral blood mononuclear cells were obtained by leukapheresis, depleted of monocytes, and cultured in the presence of interleukin 2 for 10 to 11 days. A single dose of 5.2 x 10(9) to 5.6 x 10(10) LAK cells was given intravenously. Systemic interleukin 2 was not administered. The four patients with EBV+ PTLD had complete tumor regression; two of them developed controllable rejection. Three patients are well 13-16 months after treatment; the fourth patient died of pneumonia 41 days after infusion. Three patients with EBV- lymphomas had no response despite prior evidence that their tumors also were subject to immune surveillance. Two of these three patients died after being given other treatment, and the third patient has persistent tumor. In conclusion, autologous LAK cell infusion was effective for treatment of four EBV+ organ transplant recipients. LAK cell efficacy for three patients with EBV- PTLD was not evaluable under the management circumstances in which this treatment was utilized. 相似文献
104.
105.
Electrochemical experiments, including cyclic voltammetry (CV) experiments, galvanostatic experiments, potentiostatic experiments, and kinetic experiments of the LSM electrode, were used to investigate the influence of a deposit on the electrode surface on the electrophoresis of protons in a porous media during electrophoretic deposition (EPD). 相似文献
106.
107.
Affective design is an important aspect of new product development, especially for consumer products, to achieve a competitive edge in the marketplace. It can help companies to develop new products that can better satisfy the emotional needs of customers. However, product designers usually encounter difficulties in determining the optimal settings of the design attributes for affective design. In this article, a novel guided search genetic algorithm (GA) approach is proposed to determine the optimal design attribute settings for affective design. The optimization model formulated based on the proposed approach applied constraints and guided search operators, which were formulated based on mined rules, to guide the GA search and to achieve desirable solutions. A case study on the affective design of mobile phones was conducted to illustrate the proposed approach and validate its effectiveness. Validation tests were conducted, and the results show that the guided search GA approach outperforms the GA approach without the guided search strategy in terms of GA convergence and computational time. In addition, the guided search optimization model is capable of improving GA to generate good solutions for affective design. 相似文献
108.
Two waves of technology are dramatically changing daily life: cloud computing and mobile phones. New cloud computing services such as webmail and content rich data search have emerged. However, in order to use these services, a mobile phone must be able to run new applications and handle high network bandwidth. Worldwide, about 3.45 billion mobile phones are low end phones;they have low bandwidth and cannot run new applications. Because of this technology gap, most mobile users are unable to experience cloud computing services with their thumbs. In this paper, a novel platform, Thumb-in-Cloud, is proposed to bridge this gap.Thumb-in-Cloud consists of two subsystems: Thumb-Machine and Thumb-Gateways. Thumb-Machine is a virtual machine built into a low end phone to enable it to run new applications. Thumb-Gateways can tailor cloud computing services by reformatting and compressing the service to fit the phone' s profile. 相似文献
109.
Kristian Kempe Sher Leen Ng Sylvia T. Gunawan Ka Fung Noi Frank Caruso 《Advanced functional materials》2014,24(39):6187-6194
The assembly of low‐fouling polymer capsules with redox‐responsive behavior and intracellular degradability is reported. Thiol‐containing poly(2‐ethyl‐2‐oxazoline) (PEtOxMASH) brushes are synthesized by atom transfer radical polymerization (ATRP) of oligo(2‐ethyl‐2‐oxazoline)methacrylate and glycidyl methacrylate (GMA) and subsequent ring‐opening reaction of the GMA. Sequential deposition of PEtOxMASH/poly(methacrylic acid) (PMA) multilayers onto silica (SiO2) particle templates and crosslinking through disulfide formation yield stable capsules after the removal of the SiO2 templates by buffered hydrofluoric acid (HF). The redox‐responsive nature of the disulfide crosslinking groups enables the degradation of these capsules under simulated intracellular conditions at pH 5.9 and 5 mm glutathione (GSH). Furthermore, capsule degradation is observed after incubation with dendritic (JAWS II) cells. Even at high capsule‐to‐cell ratios, PEtOxMASH capsules show only negligible cytotoxicity. Quartz crystal microgravimetry (QCM) studies, using 100% human serum, reveal that films prepared from PEtOxMASH exhibit low‐fouling properties. The degradation and low‐fouling properties are promising for application of PEtOxMASH films/capsules for the delivery and triggered release of therapeutics. 相似文献
110.
We have shown in this paper that members of the Tl-Ba-Ca-Cu-O and Bi-Sr-Ca-Cu-O superconducting families fabricated so far are built up of superconductor-semiconductor arrays. Four general homologous series are written down for these two families. The basic fundamental block in each series is itself a superconductor. We suggest that the Y-Ba-Cu-O family has a similar characteristic if YBaCu2O5-d
is a superconductor. 相似文献