全文获取类型
收费全文 | 7357篇 |
免费 | 857篇 |
国内免费 | 298篇 |
专业分类
电工技术 | 313篇 |
综合类 | 375篇 |
化学工业 | 2564篇 |
金属工艺 | 716篇 |
机械仪表 | 99篇 |
建筑科学 | 98篇 |
矿业工程 | 682篇 |
能源动力 | 73篇 |
轻工业 | 460篇 |
水利工程 | 16篇 |
石油天然气 | 135篇 |
武器工业 | 16篇 |
无线电 | 425篇 |
一般工业技术 | 967篇 |
冶金工业 | 1485篇 |
原子能技术 | 24篇 |
自动化技术 | 64篇 |
出版年
2024年 | 12篇 |
2023年 | 136篇 |
2022年 | 149篇 |
2021年 | 230篇 |
2020年 | 250篇 |
2019年 | 199篇 |
2018年 | 178篇 |
2017年 | 234篇 |
2016年 | 270篇 |
2015年 | 260篇 |
2014年 | 387篇 |
2013年 | 457篇 |
2012年 | 575篇 |
2011年 | 548篇 |
2010年 | 465篇 |
2009年 | 395篇 |
2008年 | 340篇 |
2007年 | 475篇 |
2006年 | 467篇 |
2005年 | 369篇 |
2004年 | 327篇 |
2003年 | 284篇 |
2002年 | 329篇 |
2001年 | 228篇 |
2000年 | 184篇 |
1999年 | 127篇 |
1998年 | 132篇 |
1997年 | 93篇 |
1996年 | 71篇 |
1995年 | 66篇 |
1994年 | 47篇 |
1993年 | 40篇 |
1992年 | 26篇 |
1991年 | 32篇 |
1990年 | 31篇 |
1989年 | 22篇 |
1988年 | 12篇 |
1987年 | 11篇 |
1986年 | 12篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1974年 | 3篇 |
排序方式: 共有8512条查询结果,搜索用时 15 毫秒
41.
《Ceramics International》2022,48(18):25808-25815
The harmless disposal of lead paste in the spent lead-acid batteries (LABs) remains an enormous challenge in traditional pyrometallurgical recycling. Here, we introduced a hydrometallurgical method for the recycling of the spent LABs’ waste to obtain the β-PbO as a novel zinc ion batteries (ZIBs) active material. The obtained β-PbO exhibits ultra-flat charge/discharge voltage platforms (0.21 mV/(mAh g?1)) and stable specific capacity. During the charge/discharge, the β-PbO spontaneously triggers the formation of (ZnSO4)[Zn(OH)2]3·5H2O (ZHS) micro-sheets as a surface passivation layer. Moreover, the ex-situ X-ray spectra reveal that the reversible phase transformation occurs between PbSO4 and Pb with the assistance of ZHS by adjusting the PH value on the electrode-electrolyte interface. The synergistic two-phase-reaction mechanism generates ultra-flat voltage platforms upon the charge/discharge. This “energy-saving and environment-friendly” recycling route eliminates the major source of emission of pollution particulates/gases compared to the traditional pyrometallurgical recycling, while at the same time replacing energy-consuming and environmentally detrimental processes of synthesis of current ZIBs cathodes. 相似文献
42.
43.
Amalia Mesaros Cristina D. Ghitulica Mihaela Popa Raluca Mereu Adriana Popa Traian Petrisor Jr. Mihai Gabor Adrian Ionut Cadis Bogdan S. Vasile 《Ceramics International》2014
Zn1−xCoxO (x==0.05, 0.10, 0.15) nanoparticles have been synthesized by an alternative wet-chemical synthesis route using the SimAdd technique. The as-obtained powders were investigated by FT-IR spectroscopy, X-ray diffraction and thermal analysis correlated with evolved gas analysis (TG–DTA–FT-IR) in order to determine their chemical nature, crystalline structure and to establish the decomposition sequences. The precipitates are generally amorphous, but low-intensity reflection peaks assigned both to the zinc oxalate dihydrate, and zinc hydroxide can be observed in the recorded patterns, indicating that hydroxy-oxalate precipitates were obtained. The structure, morphology and magnetic properties of the thermally treated samples have been investigated by X-ray diffraction, FT-IR, HRTEM, SAED, UV–vis and EPR. XRD studies reveal a hexagonal wurtzite-type structure for all Zn1−xCoxO samples. TEM investigations show particle size between 28 and 37 nm, with spherical and polyhedral shapes and with tendency to form aggregates. The presence of a Co3O4 secondary phase was evidenced by XRD, UV–vis and EPR for the Zn0.85Co0.15O sample. The ferromagnetic behavior of the samples was revealed. The paper highlights that by varying the cobalt concentration it is possible to modulate the structural, morphological, optical and magnetic properties. 相似文献
44.
In this research, a self-organized pattern formation employing polystyrene/aluminum bilayer coatings on three different substrates was studied. Two new substrate materials, stainless steel and zinc coated steel for self-organization application were introduced. Influence of polystyrene molar mass on pattern formation was studied with five different polystyrene samples having molar masses between 27 and 247 × 103 g/mol. Polystyrene/toluene solutions were applied onto the substrates using the spin coating technique and aluminum layer was created by chemical vapor deposition (CVD). Self-organized pattern formation was induced thermally, by heating the layered substrate/polystyrene/aluminum structures above the glass transition temperature of polystyrene. Sub-micron–micron sized wrinkles or island-like surface patterns were achieved on all substrates. The molar mass of polystyrene was found to have effect on the dimensions of the formed structures. It was also observed that the characteristic surface structure of substrates influences self-organization and thereby directs the structure formation. 相似文献
45.
46.
47.
通过对高模数无机硅酸盐进行改性,使无机富锌底漆的质量与施工使用得到改善与提高,实现了水性富锌底漆与溶剂型富锌环氧底漆施工使用同样方便,性能更好,尤其是产品的环保性能和良好的防腐性能。 相似文献
48.
利用物理复合的方法制备聚丙烯酰胺(PAM)-聚硅酸锌(PSZ)复合絮凝剂。结果表明,聚丙烯酰胺-聚硅酸锌絮凝剂在复配比例为V (PAM): V (PSZ)=1.0、投加量为0.10 mL、模拟水样pH为8左右时,对高岭土模拟废水絮凝效果最好,脱色率达91.2%,均高于聚丙烯酰胺和聚硅酸锌单独使用的效果(最高脱色率分别达87.66%和89.78%);而且,在中性和碱性范围内,这种复合絮凝剂受pH影响较小。三种絮凝剂应用于四种工业废水的脱色处理结果表明,聚丙烯酰胺-聚硅酸锌复合絮凝剂的脱色率也均比单一絮凝剂要高。 相似文献
49.
朱宝伟 《化学工业与工程技术》2014,(3):4-8
微波条件下,研究了在乙醇抽提神府煤中加入氯化锌对其结果的影响。采用气相色谱/质谱联用的方法分析了乙醇和乙醇-氯化锌抽提物的组成;利用傅里叶红外光谱技术分析了神府脱矿物质煤、乙醇抽余煤和乙醇-氯化锌抽余煤的结构。分析结果显示:在乙醇溶剂中添加少量的氯化锌,其抽提物的组成发生了改变;乙醇-氯化锌抽余煤与原脱矿物质煤和乙醇抽余煤相比,芳环吸收强度降低,表明在抽提过程中可能伴随着烷基化反应的发生。 相似文献
50.