全文获取类型
收费全文 | 2059篇 |
免费 | 95篇 |
国内免费 | 68篇 |
专业分类
电工技术 | 20篇 |
综合类 | 141篇 |
化学工业 | 287篇 |
金属工艺 | 184篇 |
机械仪表 | 324篇 |
建筑科学 | 251篇 |
矿业工程 | 433篇 |
能源动力 | 34篇 |
轻工业 | 89篇 |
水利工程 | 46篇 |
石油天然气 | 53篇 |
武器工业 | 4篇 |
无线电 | 58篇 |
一般工业技术 | 124篇 |
冶金工业 | 59篇 |
原子能技术 | 16篇 |
自动化技术 | 99篇 |
出版年
2024年 | 5篇 |
2023年 | 18篇 |
2022年 | 30篇 |
2021年 | 43篇 |
2020年 | 40篇 |
2019年 | 47篇 |
2018年 | 28篇 |
2017年 | 43篇 |
2016年 | 59篇 |
2015年 | 69篇 |
2014年 | 139篇 |
2013年 | 104篇 |
2012年 | 127篇 |
2011年 | 156篇 |
2010年 | 102篇 |
2009年 | 103篇 |
2008年 | 77篇 |
2007年 | 117篇 |
2006年 | 144篇 |
2005年 | 124篇 |
2004年 | 81篇 |
2003年 | 78篇 |
2002年 | 70篇 |
2001年 | 74篇 |
2000年 | 50篇 |
1999年 | 58篇 |
1998年 | 44篇 |
1997年 | 37篇 |
1996年 | 33篇 |
1995年 | 27篇 |
1994年 | 31篇 |
1993年 | 16篇 |
1992年 | 7篇 |
1991年 | 16篇 |
1990年 | 11篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有2222条查询结果,搜索用时 250 毫秒
1.
Geoffrey Rowden Shirley Dean James Campbell Philip Belitsky 《Microscopy research and technique》1985,2(6):547-555
Aspiration biopsy of tumors and transplanted organs is a popular atraumatic method for diagnosis and also for the management of patients. Apart from the cytological analyses, it is clear that large aggregates of cells are obtained and these may be examined by electron microscopy. A study was carried out with dogs to assess the yield of intact glomeruli and tubules, resulting from a standard fine-needle aspiration procedure. Employing a 20-gauge needle, yields of approximately ten intact glomeruli were obtained with a tissue processing protocol that utilized filtration through a nylon mesh and backwashing, to resuspend the trapped aggregates. Processing for electron microscopy was carried out in microcentrifuge tubes. The ultrastructural preservation was excellent and the extension of these studies to investigations of not only renal transplantation, but also for diagnosis in human renal diseases of a broad spectrum, is suggested. 相似文献
2.
利用先进的Gleeble-2000热模拟试验机,对GCr15轴承钢某一轧制过程进行模拟试验,测定出GCr15轴承钢动态CCT曲线,并结合微观组织分析,制定合理的GCr15轴承钢轧后控制冷却工艺,以期达到提高GCr15轴承钢质量的最终目的。 相似文献
3.
4.
Wu Songping 《Microelectronics Journal》2007,38(1):41-46
The preparation of ultra fine nickel-copper bimetallic powder with two-stage chemical reduction method was investigated. Reductive sugar and hydrazine hydrate were employed as reducing agent in different reductive stage, respectively. Reaction of CuSO4·5H2O with reductive sugar at 70 °C gives cuprous oxide and copper particles, then as-prepared mixture and nickelous hydroxide were reduced by hydrazine hydrate, and nickel-copper powder having excellent dispersibility was prepared. Influences of nickel added on composition and dispersibility of powder were studied. TG/DTG/DTA of nickel-copper powder, which is stable in room temperature, were discussed with thermal analyzer. Relation of nickel content to oxidation temperature was investigated. Ni-Cu bimetallic powder particles have a fully coated structure when nickel content is up to 30%. As-prepared nickel-copper powder was applied in base metal electrode-multilayer ceramic capacitor (BME-MLCC). The end termination has high adhesion force, fairly good densification, low resistivity, excellent solderibility behavior and resistance behavior to soldering. 相似文献
5.
We developed a noble technique for the fine-particle handling in plasmas. In this method a pair of point electrodes are introduced in the plasma, to which positive pulses are applied alternatively. When the pulse repetition period is shorter than the particle response time, the particles feel only time-averaged force because of their large mass. Spatial profile of the equivalent potential of the time-averaged force varies from a circle to an ellipse with an increase in the local discharge at the electrodes. The particles are eventually transported toward a middle point between two point-electrodes, being almost independent of their initial positions. This method is quite effective for converging fine particles in the plasma. 相似文献
6.
精细陶瓷注射成型工艺现状及发展动态 总被引:1,自引:0,他引:1
精细陶瓷注射成技术远比人们起初想象复杂的多,它已不再被人们认为是由塑料工业直接转变而来的技术。本文论述了陶瓷注射成型工艺的关键技术及其发展动态,提出了今后注射民面临的主要问题及需要加强的研究领域。 相似文献
7.
依托吉林引松工程开展隧道掘进机(TBM)施工参数预测研究,提出TBM施工数据分段提取算法,提取上升段前30 s的总推进力、刀盘转速、推进速度、刀盘扭矩、刀盘转速电位器设定值、推进速度电位器设定值、贯入度、贯入度指数(FPI)、扭矩切深指数(TPI)9个参数作为输入;通过局部线性嵌入(LLE)完成对上升段数据特征的降维;基于支持向量机回归(SVR)建立TBM施工控制参数(推进速度、刀盘转速)和负载参数(总推进力、刀盘扭矩)预测模型. 分析是否结合前一掘进循环的FPI、TPI指数进行预测对预测效果的影响. 结果表明,上述方法在推进速度、刀盘转速、总推进力、刀盘扭矩的预测中均取得了较好的预测效果,平均预测绝对百分比误差均小于15%,验证了该预测方法的有效性,该方法可以为TBM现场施工提供指导. 相似文献
8.
9.
潘锦华 《特种铸造及有色合金》2005,25(11):689-691
介绍了五台山铜塔铸造工艺,由于其结构特殊,故采用了3种工艺分别铸造而成:细砂湿模造型、树脂砂毁模贴皮造型和熔模铸造.介绍了铜塔表面化学着色技术.铜塔铸造工艺对其他相似艺术铸品具有一定的借鉴价值. 相似文献
10.