全文获取类型
收费全文 | 12899篇 |
免费 | 776篇 |
国内免费 | 485篇 |
专业分类
电工技术 | 295篇 |
综合类 | 783篇 |
化学工业 | 293篇 |
金属工艺 | 3416篇 |
机械仪表 | 1911篇 |
建筑科学 | 255篇 |
矿业工程 | 257篇 |
能源动力 | 150篇 |
轻工业 | 162篇 |
水利工程 | 108篇 |
石油天然气 | 173篇 |
武器工业 | 68篇 |
无线电 | 106篇 |
一般工业技术 | 1040篇 |
冶金工业 | 4630篇 |
原子能技术 | 60篇 |
自动化技术 | 453篇 |
出版年
2024年 | 47篇 |
2023年 | 145篇 |
2022年 | 289篇 |
2021年 | 376篇 |
2020年 | 444篇 |
2019年 | 268篇 |
2018年 | 241篇 |
2017年 | 381篇 |
2016年 | 369篇 |
2015年 | 394篇 |
2014年 | 744篇 |
2013年 | 591篇 |
2012年 | 808篇 |
2011年 | 929篇 |
2010年 | 738篇 |
2009年 | 767篇 |
2008年 | 483篇 |
2007年 | 860篇 |
2006年 | 846篇 |
2005年 | 735篇 |
2004年 | 545篇 |
2003年 | 477篇 |
2002年 | 444篇 |
2001年 | 405篇 |
2000年 | 403篇 |
1999年 | 316篇 |
1998年 | 241篇 |
1997年 | 194篇 |
1996年 | 184篇 |
1995年 | 157篇 |
1994年 | 94篇 |
1993年 | 65篇 |
1992年 | 34篇 |
1991年 | 29篇 |
1990年 | 30篇 |
1989年 | 20篇 |
1988年 | 24篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1982年 | 6篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1959年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Rectangular section control technology(RSCT)was introduced to achieve high-precision profile control during silicon steel rolling.The RSCT principle and method were designed,and the whole RSCT control strategy was developed.Specifically,RSCT included roll contour design,rolling technology optimization,and control strategy development,aiming at both hot strip mills(HSMs)and cold strip mills(CSMs).Firstly,through the high-performance variable crown(HVC)work roll optimization design in the upper-stream stands and the limited shifting technology for schedule-free rolling in the downstream stands of HSMs,a hot strip with a stable crown and limited wedge,local spot,and single wave was obtained,which was suitable for cold rolling.Secondly,an approximately rectangular section was obtained by edge varying contact(EVC)work roll contour design,edge-drop setting control,and closed loop control in the upper-stream stands of CSMs.Moreover,complex-mode flatness control was realized by coordinating multiple shape-control methods in the downstream stands of CSMs.In addition,the RSCT approach was applied in several silicon-steel production plants,where an outstanding performance and remarkable economic benefits were observed. 相似文献
2.
3.
4.
5.
根据石油开采业对石油机械产品的需求 ,利用机械理论基础知识 ,通过实践设计 ,提出了对几何尺寸长的金属管类进行调质处理后的均匀冷却方法 ,以满足其性能要求。 相似文献
6.
Behaviour of a series of lubricant oils and the effect of a non stoichiometric inorganic compound, as solid extreme pressure additive, on rolling fatigue life are studied using the rolling four-ball accelerated service simulation test proposed by Barwell and Scott. The results show, in all tested cases, the remarkable efficacy of this type of additive. The Total Acidity Number (tan) was found to increase with performance time for the case of the base lubricant, while for the oils with additives, it remained at its constant low value. This led to a proposal of a possible mechanism of the additive performance in the rolling process. 相似文献
7.
8.
采用被动式工艺生产冷轧带肋钢筋须经过减径、成型两台轧机连续轧制.要求钢材的秒流量相等,否则将造成断线停产或线材在拉丝机卷筒上打滑,致使卷筒严重磨损.用双层卷筒拉丝机提供动力生产冷轧带肋钢筋时,线材直径与卷筒直径的匹配是在一个小的调整范围,通过轧机拉力控制在一定范围变化,可保证成品尺寸符合公差要求而不产生打滑,从而避免了卷筒严重磨损. 相似文献
9.
在薄板坯连铸连轧流程上,经过对Ti微合金化技术研究,有效解决了Ti微合金化强度性能波动大的问题,开发出屈服强度450~700MPa高强钢。对试制钢组织性能和工业应用分析研究,表明该产品通板性能良好,通板强度差30MPa左右;成形性能良好,d=0时冷弯测试全部合格;同时还具有良好焊接性能,焊接后,强度波动较小,均在母材部位断开;试制钢显微组织为珠光体和铁素体,晶粒均匀细小,平均尺寸为4~8/μm;实物质量满足集装箱和汽车制造行业要求,具有广阔市场前景。 相似文献
10.
Total simulation model of the thermo-mechanical process in shape rolling of steel rods 总被引:2,自引:0,他引:2
The production of steel reinforcing bars for civil engineering is investigated by means of FEM-simulation. An integrated system for computing appropriate thermo-mechanical parameters of the rolling process is proposed. Generalized plane strain approach and coupled thermal-mechanical solution are applied. The microstructural model combines both the effect of the recrystallization mechanisms (static, dynamic and metadynamic) upon the austenite grain forming in hot rolling and that of phase transformation upon the final microstructure. The phases are created during interrupted below the temperature of martensite transition cooling. Thus a typical industrial process for thermo-mechanical strengthening of reinforcing bars, known as Tempcor-process is considered. Computational results are validated to experimental measured mechanical properties of the steel. By means of computer simulation the system can perform different solutions, giving the possibility to obtain a reasonable choice of different thermo-mechanical rolling conditions. 相似文献