全文获取类型
收费全文 | 18581篇 |
免费 | 1182篇 |
国内免费 | 437篇 |
专业分类
电工技术 | 883篇 |
综合类 | 1168篇 |
化学工业 | 2848篇 |
金属工艺 | 2878篇 |
机械仪表 | 2621篇 |
建筑科学 | 763篇 |
矿业工程 | 1757篇 |
能源动力 | 473篇 |
轻工业 | 1403篇 |
水利工程 | 178篇 |
石油天然气 | 323篇 |
武器工业 | 72篇 |
无线电 | 386篇 |
一般工业技术 | 945篇 |
冶金工业 | 3064篇 |
原子能技术 | 27篇 |
自动化技术 | 411篇 |
出版年
2024年 | 67篇 |
2023年 | 196篇 |
2022年 | 324篇 |
2021年 | 413篇 |
2020年 | 464篇 |
2019年 | 335篇 |
2018年 | 375篇 |
2017年 | 485篇 |
2016年 | 542篇 |
2015年 | 539篇 |
2014年 | 1046篇 |
2013年 | 849篇 |
2012年 | 1282篇 |
2011年 | 1384篇 |
2010年 | 971篇 |
2009年 | 994篇 |
2008年 | 754篇 |
2007年 | 1274篇 |
2006年 | 1125篇 |
2005年 | 1011篇 |
2004年 | 865篇 |
2003年 | 786篇 |
2002年 | 724篇 |
2001年 | 618篇 |
2000年 | 577篇 |
1999年 | 435篇 |
1998年 | 379篇 |
1997年 | 301篇 |
1996年 | 248篇 |
1995年 | 204篇 |
1994年 | 184篇 |
1993年 | 101篇 |
1992年 | 89篇 |
1991年 | 86篇 |
1990年 | 32篇 |
1989年 | 47篇 |
1988年 | 38篇 |
1987年 | 15篇 |
1986年 | 8篇 |
1985年 | 15篇 |
1984年 | 6篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
对鞍钢股份无缝钢管厂连轧机前毛管坯横移装置存在的设计缺陷进行了分析,并提出改进方案,将原横移装置由高架轨道横移机构及上下升降链传动装置,改进为地面轨道横移系统及同步旋转臂实现取管、放管过程。实施后消除了生产故障,缩短了轧制周期,降低生产成本。 相似文献
2.
M. R. Thompson 《Drug development and industrial pharmacy》2015,41(8):1223-1231
Twin screw granulation (TSG) is a new process of interest to the pharmaceutical community that can continuously wet granulate powders, doing so at lower liquid concentrations and with better product consistency than found by a high shear batch mixer. A considerable body of research has evolved over the short time since this process was introduced but generally with little comparison of results. A certain degree of confidence has been developed through these studies related to how process variables and many attributes of machinery configuration will affect granulation but some major challenges still lay ahead related to scalability, variations in the processing regimes related to degree of channel fill and the impact of wetting and granulation of complex powder formulations. This review examines the current literature for wet granulation processes studied in twin screw extrusion machinery, summarizing the influences of operational and system parameters affecting granule properties as well as strives to provide some practical observations to newly interested users of the technique. 相似文献
3.
4.
以废弃的流化催化裂化催化剂(简称SFCC)为载体、β-环糊精为金属络合剂、硝酸镍为镍源,采用湿法浸渍法制备β-环糊精修饰的Ni/SFCC催化剂(简称Ni/SFCC-CD催化剂),考察其对C9石油树脂的催化加氢性能。通过BET比表面积测试、H2程序升温还原、X射线光电子能谱等手段对催化剂的物相结构进行表征,研究β-环糊精的作用机理及其对催化剂加氢性能的影响。研究结果表明:在反应温度为260 ℃、反应压力为7 MPa、反应时间为2.0 h的最优条件下,采用Ni/SFCC-CD催化C9石油树脂加氢,可制得溴值为1.45 gBr/(100 g)、色号(加纳德)小于1的水白色氢化C9石油树脂,催化剂循环使用4次后仍保持良好活性;β-环糊精的作用机理是:β-环糊精与硝酸镍产生络合作用,抑制硝酸镍的分解、控制NiO的结晶过程和增强活性组分Ni与载体之间的相互作用力,从而提高了Ni/SFCC-CD的催化活性和稳定性。 相似文献
5.
Muralidhar N. Ingale Vijaykumar V. Mahajani 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1995,64(1):80-86
The effectiveness of the hybrid system sonication followed by wet oxidation (SONIWO) to treat otherwise refractory waste has been demonstrated. In such a hybrid system homogeneous CuSO4 catalyst was found to be very efficient. 相似文献
6.
济钢燃气厂针对济钢转炉煤气储存加压系统的设备现状,组织了一次设备大修,大修后煤气柜升降速度提高到了1.0m/min,并解决了加压机前负压等问题。 相似文献
7.
8.
Toshihiko Hoshide Junpei Fujita 《Journal of Materials Engineering and Performance》2008,17(5):627-632
Strength of ground ceramics may be affected by residual stress as well as surface flaws induced by grinding. Strength prediction
for ground ceramics is convenient for mechanical design of ceramic components. In this article, a numerical procedure based
on fracture mechanics was proposed to estimate strength distribution of ground ceramics by considering grinding-induced residual
stress. Bending strength and residual stress of ground ceramics were measured for three grinding-conditions. By comparison
of simulated results with experimental ones, it was revealed that strength characteristics in experiments were well simulated
by using the proposed procedure. 相似文献
9.
Hakan Benzer 《Powder Technology》2005,150(3):145-154
A raw material grinding circuit was modeled using plant data. Samples were collected from around the circuit and, following a crash stop, from inside the mill. The size distributions of the samples were determined down to a few microns. Using the data from inside the mill a modeling approach, based on perfect mixing, was developed. The modelling approach implicitly assumes that the mixture of feed materials broken is homogenous from the breakage point of view. The air classification around the circuit was modeled using the efficiency curve approach. In order to measure the success of the method the circuit performance was predicted by simulation studies while it was operating at different conditions. The results were then compared with the measured data. It is concluded that modeling gives a useful quantitative indication of what may occur in fully air swept mills. 相似文献
10.
制备单根大重量喷涂钼丝的生产研究 总被引:3,自引:0,他引:3
全面系统地介绍了“大坯料轧制开坯-大加工率变形-长线拉伸”制造喷涂钼丝的工艺。重点阐述了Y370、Y250型三辊连轧机实现一火轧制开坯和长线拉伸增加在线碱洗工序对提高喷涂钼丝内部组织结构和外部表面质量的影响。分析了工艺中出现的问题,提出了相应的解决办法。 相似文献