全文获取类型
收费全文 | 13259篇 |
免费 | 1228篇 |
国内免费 | 516篇 |
专业分类
电工技术 | 494篇 |
综合类 | 878篇 |
化学工业 | 2011篇 |
金属工艺 | 3709篇 |
机械仪表 | 1340篇 |
建筑科学 | 591篇 |
矿业工程 | 342篇 |
能源动力 | 287篇 |
轻工业 | 1014篇 |
水利工程 | 160篇 |
石油天然气 | 854篇 |
武器工业 | 115篇 |
无线电 | 637篇 |
一般工业技术 | 1536篇 |
冶金工业 | 780篇 |
原子能技术 | 38篇 |
自动化技术 | 217篇 |
出版年
2024年 | 37篇 |
2023年 | 184篇 |
2022年 | 267篇 |
2021年 | 294篇 |
2020年 | 349篇 |
2019年 | 258篇 |
2018年 | 271篇 |
2017年 | 401篇 |
2016年 | 402篇 |
2015年 | 439篇 |
2014年 | 724篇 |
2013年 | 639篇 |
2012年 | 906篇 |
2011年 | 956篇 |
2010年 | 743篇 |
2009年 | 843篇 |
2008年 | 702篇 |
2007年 | 941篇 |
2006年 | 915篇 |
2005年 | 772篇 |
2004年 | 701篇 |
2003年 | 634篇 |
2002年 | 551篇 |
2001年 | 505篇 |
2000年 | 408篇 |
1999年 | 247篇 |
1998年 | 184篇 |
1997年 | 178篇 |
1996年 | 166篇 |
1995年 | 99篇 |
1994年 | 89篇 |
1993年 | 49篇 |
1992年 | 49篇 |
1991年 | 25篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1979年 | 2篇 |
1956年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
我公司使用的硫化机采用氮气定型,二次水硫化的工艺。由于特种工程胎胎体偏厚且大,成型机都比较大,生产过程中的帘布筒、钢丝、胎侧等部件都比较重且大。成型胎面使用胎面缠绕机缠绕,所以整个生产过程难度较大。特种工程胎硫化外胎的主要质量问题有:胎面皮泡、胎侧缺胶、胎侧泡、胎肩侧皮泡、子口内侧露线、子口缺胶、胎肚内缺(窝气)、胎肚露线、胎肚皮泡、胎肚串泡、子口支边、胎冠支边、子口鼓包、外胎花缺等。通过对特种工程胎硫化外胎质量缺陷原因分析,找到相应的解决措施,从而减少硫化外胎质量缺陷。 相似文献
2.
Xuejie Li Yaqing Wen Jian Zhang Dongyun Ma Jie Zhang Yanxia An Xiaoyan Song Xiujuan Ren Weifeng Zhang 《International Journal of Food Science & Technology》2022,57(3):1544-1553
The effects of non-thermal plasma (NTP) on the physicochemical properties of wheat flour and the quality of fresh wet noodles ( FWN) were investigated. The results showed that NTP effectively decreased the total plate count (TPC), yeast and mould count (YMC) and Bacillus spp. in wheat flour. Wet gluten contents and the stability time reached the maximum when treated for 20 s. The viscosity of starch increased significantly after treatment due to the increased of damaged starch. The contents of secondary structure were altered to some extent, which was because that the ordered network structure of gluten protein broken. Furthermore, compared with the control, texture properties of FWN were enhanced significantly at 20 s, and the darkening rate of FWN was greatly inhibited due to the low polyphenol oxidase (PPO) activity. Consequently, the most suitable treatment was 500 W for 20 s, providing a basis for the application of NTP in flour products. 相似文献
3.
The dependence of the maximum and minimum wet thicknesses on the coating gap is derived for the slot-die coating process, under different slot-die configurations. Analytical expressions for the wet thickness and its derivative with respect to the coating gap are obtained using a simple flow model. The results indicate that, as expected, the minimum wet thickness increases linearly with the coating gap; however, the maximum wet thickness demonstrates a counterintuitive trend of decreasing as the coating gap increases, when a specific slot-die configuration is assumed. Moreover, the results are also validated by numerically solving the complete two-dimensional (2D) Navier–Stokes equation. 相似文献
4.
《International Journal of Hydrogen Energy》2022,47(40):17737-17748
Due to problems such as pores on surface-treated coatings, the corrosion resistance of pure titanium bipolar plates for proton-exchange membrane fuel cells can be further improved by increasing the corrosion resistance of pure titanium by using differential speed-rolling (DSR); however, these materials have not yet reached the standard requirements of bipolar plates (corrosion current density icorr<103 nA·cm?2). In this work, the corrosion resistance of pure titanium was improved by optimizing the DSR process while the strength was maintained. The best corrosion resistance of the DSR pure titanium was achieved when the roller speed ratio was 2, while icorr was 429 nA·cm?2 in a solution of 0.5 M H2SO4 and 2 mg/L HF at room temperature. The formability of the DSR pure titanium for bipolar plates was verified. The optimal holding pressure range was 6.8–7.0 kN. 相似文献
5.
6.
Bijan Nasri‐Nasrabadi Akif Kaynak Shayan Seyedin Zahra Komeily‐Nia Abbas Z Kouzani 《Polymer International》2019,68(5):922-928
Recent advances in three‐dimensional (3D) printing have enabled the fabrication of interesting structures which are not achievable using traditional fabrication approaches. The 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks, which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through a facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions with a chitosan polymer matrix are achieved. Consequently, the mechanical properties of the 3D printed composites improve when nanogrooved carbon microtubes are used, compared to untreated microtubes. We show that by carefully controlling the coagulation bath, extrusion pressure, printing distance and printed line distance, we can 3D print composite lattices which are composed of well‐defined and separated printed lines. The conductive composite 3D structures with highly customised design presented in this work provide a suitable platform for applications ranging from soft robotics to smart tissue engineering scaffolds. © 2019 Society of Chemical Industry 相似文献
7.
为探究[Zr_(0.73)(Cu_(0.59)Ni_(0.41))_(0.27)]_(87)Al_(13)非晶合金的热塑性成形性能以及绘制其对应的热加工图谱,用Gleeble3500型热模拟压缩实验机对该非晶合金进行不同参数下的热模拟压缩实验。结果表明,合金在压缩过程中变形行为由牛顿流变演变为非牛顿流变;同时,过高或过低的热加工温度均能导致合金晶化;进一步对数据分析得到该合金在不同热塑性成形参数下的功率耗散图与流变失稳图,并绘制出相应的热加工谱图,谱图分析结果表明,该合金在温度为420与430℃、应变速率为10~(-3) s~(-1)时具有较高功率耗散系数且没有失稳区域,因此,合金可选的热塑性加工参数为温度420~430℃,应变速率10~(-3) s~(-1)。 相似文献
8.
Christopher Fleming 《工业材料与腐蚀》2019,70(9):1617-1632
Hexagonal boron nitride (h‐BN) coatings on Ti‐6Al‐4V substrates undergo complete decomposition in air at 900 °C. This fate is similar to that of this ceramic material on chromia‐former alloys, and unlike that of a mass of powder treated in isolation. As the ceramic and alloy oxidize concurrently, outwardly diffusing aluminum (III) ions but not the predominant titanium (IV) ions react with the boron trioxide that forms around the h‐BN basal plane peripheries. Resultant aluminum borate is incorporated into the growing scale and the boron trioxide diffusion barrier is depleted. By this mechanism, the oxidation of h‐BN is maintained at an enhanced rate, until both this material and its oxide completely decompose. Liberated nitrogen from the oxidation of h‐BN can enter the underlying scale as a randomly distributed solute in rutile solid solution. The post‐coating oxide‐atmosphere interface comprises elongated aluminum borate crystallites protruding through at the boundaries between 3–5 at% nitrogen‐doped rutile grains. It differs significantly from that of oxidized, uncoated Ti‐6Al‐4V, which is occupied by a thin α‐alumina layer atop rutile. This interface does not change with an additional 72 h of heat‐treatment. 相似文献
9.
10.
AbstractIn this study, 3D hemispherical forming experiments are conducted to analyze the conformability behavior of nylon 66 plain woven reinforcements with different weft densities. To make insight into the forming process, a macro finite element model is also proposed for 3D forming of a specific woven reinforcement by using the defined ‘Fabric’ material. The results show that the proposed FEM modelling is highly correlated with experimental findings in terms of forming energy values with small and insignificant errors values, which confirm well model validity. It shows that the nylon 66 composite woven reinforcement with a lower weft density exhibits a lower forming energy (toughness) and hence a higher conformability over a hemispherical surface. On the other hand, modeling outputs clearly indicate that more wrinkling intensity appear for woven reinforcement with a higher weft density. 相似文献