全文获取类型
收费全文 | 1323篇 |
免费 | 204篇 |
国内免费 | 68篇 |
专业分类
电工技术 | 176篇 |
综合类 | 83篇 |
化学工业 | 175篇 |
金属工艺 | 94篇 |
机械仪表 | 61篇 |
建筑科学 | 102篇 |
矿业工程 | 40篇 |
能源动力 | 53篇 |
轻工业 | 128篇 |
水利工程 | 37篇 |
石油天然气 | 20篇 |
武器工业 | 55篇 |
无线电 | 185篇 |
一般工业技术 | 117篇 |
冶金工业 | 95篇 |
原子能技术 | 3篇 |
自动化技术 | 171篇 |
出版年
2024年 | 14篇 |
2023年 | 46篇 |
2022年 | 103篇 |
2021年 | 132篇 |
2020年 | 128篇 |
2019年 | 56篇 |
2018年 | 45篇 |
2017年 | 48篇 |
2016年 | 36篇 |
2015年 | 22篇 |
2014年 | 123篇 |
2013年 | 123篇 |
2012年 | 191篇 |
2011年 | 112篇 |
2010年 | 92篇 |
2009年 | 77篇 |
2008年 | 49篇 |
2007年 | 73篇 |
2006年 | 58篇 |
2005年 | 14篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1595条查询结果,搜索用时 9 毫秒
51.
某型履带车辆紧急制动动力学仿真分析 总被引:1,自引:0,他引:1
基于虚拟样机技术,用ADAMS/ATV模块建立了某型履带车辆紧急制动的动力学模型。通过实车的行驶试验和紧急制动试验对模型进行了验证,结果表明所建动力学模型在反映履带车辆行驶及紧急制动动力学行为方面能够满足工程分析的需要。将其作为分析平台,对履带车辆进行了以相同初速度在不同路面以及同一路面不同初速度情况下紧急制动动力学仿真分析,仿真结果表明,其符合在相同的路面制动初速度越大制动距离越远以及制动初速度相同的情况下,路面不平度越大制动距离越短的实际情况。 相似文献
52.
分析了双相不锈钢阀门铸件经常出现裂纹缺陷的原因.为避免再次投产时阀门铸件裂纹缺陷的产生,制定了相应的措施:提高砂芯的退让性;严格控制钢液的化学成分,特别是磷硫元素的含量控制;添加稀土元素细化晶粒,净化钢液以提高抗裂性;清除浇冒口和补焊注意温度的控制.结果表明,通过上述措施后,重新投产的阀门铸件没有裂纹缺陷. 相似文献
53.
为了抑制铣削过程中产生的颤振,提高铣削加工过程中零部件表面质量.设计了小波神经网络PID控制方法,并对控制效果进行仿真.采用时域数值法对动态铣削过程中离散时间进行求解,利用小波神经网络PID控制方法对铣削过程进行控制.通过仿真和实验对铣削金属表面粗糙度进行测量,并且与增量式PID控制系统进行比较和分析.结果显示,采用增... 相似文献
54.
We consider the problem of scheduling a set of jobs on a single machine against a common and restrictive due date. In particular, we are interested in the problem of minimizing the weighted sum of maximum earliness and maximum tardiness costs. This kind of objective function is related to the just-in-time environment where penalties, such as storage cost and additional charges for late delivery, should be avoided. First we present a mixed integer linear model for the problem without availability constraints and we prove that this model can be reduced to a polynomial-time model. Secondly, we suppose that the machine undergoes a periodic preventive maintenance. We present then a second mixed integer linear model to solve the problem to optimality. Although the latter problem can be solved to optimality for small instances, we show that the problem reduces to the one-dimensional bin packing problem. Computational results show that the proposed algorithm best fit decreasing performs well. 相似文献
55.
三网融合的大背景,使有线电视网络改造变得迫在眉睫,整改后的城域网标准应该是符合NGB发展方向的优质网络。 相似文献
56.
57.
58.
Red sweet peppers (Capsicum annuum) are an excellent source of essential nutrients and bioactive compounds. High hydrostatic pressures (HHP) not only increase shelf-life but also maintain nutritional and organoleptic properties better in a number of food products. The aim of this work was to measure the effect of HHP and a thermal treatment, pasteurization (PA) in a water bath at 70 °C for 10 min, on some bioactive compounds (fibre, carotenoids and antioxidant activity) and on the texture (TPA; firmness and shear force) of red Lamuyo-type sweet peppers, in order to discover the relationship between treatment (HHP and PA), tissue microstructure and bioactive compound extractability. The results show that HHP at 500 MPa and PA treatments had less impact on the microstructure, bioactive compound content (fibre and antioxidant activity) and texture of red sweet peppers, than when low pressures were used. Consequently, new functional foods could be developed using red sweet pepper tissues treated with high pressures (500 MPa) and/or PA.Industrial relevanceToday’s consumers demand foods that are rich in bioactive compounds with beneficial health effects and safer, more natural, minimally-processed food products. Red sweet peppers (Capsicum annuum) are an excellent source of essential nutrients and bioactive compounds such as carotenoids and fibre. High hydrostatic pressure (HHP) processing is considered one of the most economically viable of the non-thermal technologies that helps to preserve red sweet peppers with high nutritional and quality parameters. Therefore, it would be interesting to study the microstructure of HHP-treated red sweet pepper tissues in order to discover whether this treatment promotes the extractability of bioactive compounds, and to compare the results with those obtained by pasteurizing the red sweet pepper. Thus, these enhanced red sweet peppers could be used as ingredients in the formulation of new functional foods. 相似文献
59.
60.