全文获取类型
收费全文 | 805篇 |
免费 | 19篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 113篇 |
化学工业 | 189篇 |
金属工艺 | 14篇 |
机械仪表 | 19篇 |
建筑科学 | 10篇 |
矿业工程 | 2篇 |
能源动力 | 28篇 |
轻工业 | 83篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 80篇 |
一般工业技术 | 144篇 |
冶金工业 | 68篇 |
原子能技术 | 27篇 |
自动化技术 | 48篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 19篇 |
2020年 | 6篇 |
2019年 | 14篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 20篇 |
2014年 | 14篇 |
2013年 | 54篇 |
2012年 | 33篇 |
2011年 | 47篇 |
2010年 | 34篇 |
2009年 | 39篇 |
2008年 | 46篇 |
2007年 | 48篇 |
2006年 | 39篇 |
2005年 | 27篇 |
2004年 | 26篇 |
2003年 | 32篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 22篇 |
1999年 | 15篇 |
1998年 | 33篇 |
1997年 | 26篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 16篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 10篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有829条查询结果,搜索用时 15 毫秒
71.
Phosphorylation is a useful method for improving the functional properties of food proteins. In this article, various methods of phosphorylation are reviewed. Dry-heating phosphorylation, a method developed recently, is also introduced. Some characteristics of phosphate groups are involved, and the effects of phosphorylation on the structural changes, the functional properties, and the physiological functions in vitro of food proteins, are discussed. The types of phosphate linkages and the phosphopeptides from phosphorylated proteins are identified. The molten (partially unfolded) conformations of food proteins formed by phosphorylation are discussed. The phosphorylation of food proteins improved a number of functional properties, including heat stability, emulsifying properties, foaming properties, gelling properties, water absorption capacity, oil absorption capacity, and calcium phosphate-solubilizing ability. In vitro physiological function studies of protein (α-lactoalbumin) indicated that the digestibility (ovalbumin) was improved and the inflammatory response (α-lactoalbumin) was suppressed by phosphorylation. Experiments with animals are necessary to evaluate the toxicity and physiological functions of phosphorylated proteins. 相似文献
72.
高档的通信设备曾一度只能在办公环境中才能使用,然而现在这种情况已经改变,家庭中已经普遍具备了互连能力,许多家用电子设备现在通过Ipv6和其他技术已经具备了上网能力。随着宽带通信应用的增加,调制解调器、各种DSL接入复用器以及其他类似设备的安装已经遍及办公室和家庭,消费者可以方便获得价廉的通信设备。对于设备制造商来说,这些装置必须满足安全标准,如IEC60950(InternationalElectrotechnicalCommission第三版),它要求在与数据通信线连接的设备上实现电话网络高压电路的隔离。一般情况下,人们采用传统的电磁通信继电器来开关内… 相似文献
73.
74.
75.
Any solution for an inverse heat conduction problem makes the estimation of surface temperature and surface heat flux worsen in the case where these values behave like a triangular shape change with time. In order to compensate for this defect, Monde and colleagues, who succeeded in obtaining analytical inverse solutions using the Laplace transform technique, introduce a new idea where these changes over the entire measurement time can be split into several parts depending on the behavior. Therefore, an approximate equation to trace the measured temperature change can be derived, resulting in good estimation of surface temperature and surface heat flux even in the case of the triangular shape change and sharp change. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(7): 630–638, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10117 相似文献
76.
试验了彩色聚乙烯涂覆钢管的耐腐蚀性和耐气候性,由于聚乙烯涂层隔绝水的作用,聚乙烯涂覆钢管具有优良的耐腐蚀性能,电阻绝缘值和优良的机械性能。建立了一个新的方式去研究分析聚乙烯抗老化剂消耗和在聚乙烯中的扩散。用有效测定的方法定量地预测彩色聚乙烯涂覆层的寿命,应用这些分析结果,不仅可使新的有色聚乙烯涂覆钢管在恶劣腐蚀环境介质情况下具有高的耐腐蚀性,而且有长的耐气候性。 相似文献
77.
We have studied a new timing circuit in which the input signal is put out at the same time as the clock signal. This is a key element for the realisation of Josephson vortex logic. We propose a new device structure which consists of two Josephson transmission lines connected by a resistor and a vortex trapping site (VTS). In this device a signal vortex is trapped in the VTS and it is repropagated to the output when the clock signal vortex propagates to the turning point. The quasistatic operation of this device is confirmed experimentally. 相似文献
78.
Shizuo Saitoh Hirofumi Daiguji Eiji Hihara 《International Journal of Heat and Mass Transfer》2007,50(25-26):5215-5225
A Chen-type correlation for flow boiling heat transfer of R-134a in horizontal tubes was modified taking into account the effect of tube diameter. The effect of tube diameter on flow boiling heat transfer coefficient was characterized by the Weber number in gas phase. Results showed that this correlation could be applied to a wide range of tube diameters (0.5–11-mm-ID). In addition, the dryout point and the heat transfer characteristics after the dryout point were also investigated based on the annular flow model. The proposed experimental expressions to predict both the dryout quality and the post-dryout heat transfer coefficient could also be applied to a wide range of tube diameter (0.5–11-mm-ID). 相似文献
79.
An analytical method using Laplace transformation has been developed for one‐dimensional heat conduction. This method succeeded in explicitly deriving the analytical solution by which the surface temperature for the first kind of boundary condition can be well predicted. The analytical solutions for the surface temperature and heat flux are applied to the second and third of the boundary conditions. These solutions are also found to estimate the corresponding surface conditions with a high degree of accuracy when the surface conditions smoothly change. On the other hand, when these conditions erratically change such as the first derivative of temperature with time, the accuracy of the estimation becomes slightly less than that for a smooth condition. This trend in the estimation is similar irrespective of any kind of boundary condition. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(1): 29–41, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10069 相似文献
80.
The deposition of gold ions from atomic force microscope cantilever tips onto bulk insulating substrates with nearby surface electrodes is discussed. Numerical models of the potential distribution are used to estimate potential barriers for the desorption process. These models indicate deposition height thresholds of 7-10 nm with the tip 20-25 nm from the metallic electrode edge over a KBr surface but greater than 20 nm high for InP/GaAs/InP substrates with a two-dimensional electron gas (2DEG) as the back electrode. Experimental results for the deposition of gold clusters over KBr surfaces near metal electrodes in ultra-high vacuum (UHV) are presented and show promising agreement with calculations of the deposition threshold heights. Deposition of clusters over InP is discussed for comparison and indicates similar trends. 相似文献