全文获取类型
收费全文 | 969篇 |
免费 | 83篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 20篇 |
综合类 | 1篇 |
化学工业 | 247篇 |
金属工艺 | 17篇 |
机械仪表 | 24篇 |
建筑科学 | 36篇 |
矿业工程 | 6篇 |
能源动力 | 26篇 |
轻工业 | 94篇 |
水利工程 | 7篇 |
无线电 | 90篇 |
一般工业技术 | 181篇 |
冶金工业 | 39篇 |
原子能技术 | 20篇 |
自动化技术 | 246篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 41篇 |
2021年 | 68篇 |
2020年 | 46篇 |
2019年 | 33篇 |
2018年 | 34篇 |
2017年 | 39篇 |
2016年 | 45篇 |
2015年 | 33篇 |
2014年 | 45篇 |
2013年 | 67篇 |
2012年 | 64篇 |
2011年 | 77篇 |
2010年 | 52篇 |
2009年 | 51篇 |
2008年 | 50篇 |
2007年 | 27篇 |
2006年 | 42篇 |
2005年 | 27篇 |
2004年 | 21篇 |
2003年 | 22篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 7篇 |
1999年 | 14篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 12篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 7篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有1054条查询结果,搜索用时 15 毫秒
31.
The purposes of this work were to obtain the accurate elastic modulus of the nanocrystalline WC–Co cemented carbides, and to propose the mechanism for the difference of elastic modulus between the nanocrystalline and conventional polycrystalline cemented carbides. The nanocrystalline cemented carbide was prepared by spark plasma sintering (SPS) technique. The conventional polycrystalline cemented carbides were prepared by SPS and sinter-HIP techniques as references, respectively. The sintered cemented carbides were characterized by X-ray diffractometry, scanning electron microscopy and the transmission electron microscopy with precession electron diffraction technology. The elastic modulus was obtained by averaging the values measured with the continuous stiffness measurement method of the nanoindentation technology. The results show that the nanocrystalline cemented carbide has a relatively low modulus, which could be attributed to the more interface area and higher fraction ratio of the hcp cobalt phase caused by the rapid heating and cooling process during SPS. 相似文献
32.
V. Riccardo P. Lomas G.F. Matthews I. Nunes V. Thompson E. Villedieu 《Fusion Engineering and Design》2013,88(6-8):585-589
The aim of the JET ITER-like wall project was to provide JET with the plasma facing material combination now selected for the DT phase of ITER (bulk beryllium main chamber limiters and a full tungsten divertor) and, in conjunction with the upgraded neutral beam heating system, to achieve ITER relevant conditions.The design of the bulk Be plasma facing components had to be compatible with increased heating power and pulse length, as well as to reuse the existing tile supports originally designed to cope with disruption loads from carbon based tiles and be installed by remote handling. Risk reduction measures (prototypes, jigs, etc.) were implemented to maximize efficiency during the shutdown. However, a large number of clashes with existing components not fully captured by the configuration model occurred.Restarting the plasma on the ITER-like Wall proved much easier than for the carbon wall and no deconditioning by disruptions was observed. Disruptions have been more threatening than expected due to the reduced radiative losses compared to carbon, leaving most of the plasma magnetic energy to be conducted to the wall and requiring routine disruption mitigation. The main chamber power handling has achieved and possibly exceeded the design targets. 相似文献
33.
34.
35.
36.
37.
Liliana Caristia Giuseppe Nicotra Corrado Bongiorno Nicola Costa Sebastiano Ravesi Salvo Coffa Riccardo De Bastiani Maria Grazia Grimaldi Corrado Spinella 《Microelectronics Reliability》2007,47(4-5):777
This work reports the study concerning the influence of the preparation conditions on the structure of silicon rich oxide (SRO) deposited by PECVD method by which the structural properties of the film are strictly related. In particular we investigated the role of reactant gases N2O and SiH4 on the total Si concentration, Si excess concentration, Si clustered concentration and size of nanoclusters formed by high annealing temperature. We payed particular attention on the role of the hydrogen and nitrogen during the Si agglomeration.The presence of hydrogen atoms on the as-deposited specimen, confirmed by the Si–H bonds peak on the FTIR analysis, has been directly correlated to the silicon excess concentration in the layer. The silicon, oxygen and nitrogen atomic density has been calculated from RBS analysis. These information were coupled to the ones obtained using methodology based on electron energy loss spectroscopy combined with energy filtered images, which allowed us to quantify the clustered silicon concentration in annealed sub-stoichiometric silicon oxide layers (SiOx). We have verified that the nitrogen dissolved in the layer inhibits the Si excess clustering so that the efficiency of silicon agglomeration process decreases as the nitrogen content increases. 相似文献
38.
夏文水 《食品与生物技术学报》1996,15(1)
壳聚糖及其衍生物能很容易被脂肪酶解聚。当壳聚糖乳酸盐溶液与脂肪酶在25℃下作用10min后,其溶液粘度被降低到初始值的35%,分子量从约700kDa减少到13kDa(还原糖滴定法测定)。脂肪酶浓度在4.5×10-3~9×10-1g/L范围内,解聚初速度与酶浓度成对数线性关系。N-羧甲基壳聚糖比壳聚糖更容易被脂肪酶解聚。 相似文献
39.
Design and control of an AS/RS 总被引:2,自引:0,他引:2
Riccardo Manzini Mauro Gamberi Alberto Regattieri 《The International Journal of Advanced Manufacturing Technology》2006,28(7-8):766-774
Automated storage/retrieval systems (AS/RSs) are a combination of equipment and controls which automatically handle, store
and retrieve materials (components, tools, raw material and subassemblies) with great speed and accuracy. Consequently, they
are widely used in industrial companies to manage products with cost-effective utilization of time, space and equipment. This
paper presents a multi-parametric dynamic model of a product-to-picker storage system with class based storage allocation
of products. Thousands of what-if scenarios are simulated in order to measure the impact of alternative design and operating
configurations on the expected system performance and to identify the most critical factors and combinations of factors affecting
the response of the system. Class based storage proves to be a very effective way of both reducing the picking cycle time
and maximizing the throughput of the system. The rapid effectiveness of visual interactive simulation (VIS) in supporting
the design (redesign) and control of new (existing) warehouses emerges, responding to the need for flexibility which modern
companies need in order to adapt to strongly changing operating conditions quickly. 相似文献
40.
Relationships among stressful life events, negative affect, and judged quality of intimate relationships were explored. Three studies and a mini-meta-analysis revealed that as negative life events increased, judgments of close relationships gradually became less favorable, jumped back toward positivity, and then, again, gradually became less favorable. The same methods of analysis revealed a relationship between negative life events and negative affect with no evidence of significant discontinuities. Moreover, the correlation between relationship satisfaction and negative affect (with negative events held constant), was maximized at the point of relationship-judgment discontinuity. Although the findings are complex, they are consistent with the authors' theoretical account and represent an initial attempt to conceptualize the effect of negative life events in light of the recent social judgment literature. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献