全文获取类型
收费全文 | 111251篇 |
免费 | 11033篇 |
国内免费 | 6116篇 |
专业分类
电工技术 | 8295篇 |
技术理论 | 8篇 |
综合类 | 7959篇 |
化学工业 | 17760篇 |
金属工艺 | 6271篇 |
机械仪表 | 7002篇 |
建筑科学 | 9291篇 |
矿业工程 | 3494篇 |
能源动力 | 3263篇 |
轻工业 | 7551篇 |
水利工程 | 2437篇 |
石油天然气 | 6740篇 |
武器工业 | 1079篇 |
无线电 | 13014篇 |
一般工业技术 | 13169篇 |
冶金工业 | 4852篇 |
原子能技术 | 1165篇 |
自动化技术 | 15050篇 |
出版年
2024年 | 599篇 |
2023年 | 2301篇 |
2022年 | 4211篇 |
2021年 | 5820篇 |
2020年 | 4236篇 |
2019年 | 3375篇 |
2018年 | 3610篇 |
2017年 | 4025篇 |
2016年 | 3628篇 |
2015年 | 4724篇 |
2014年 | 6008篇 |
2013年 | 6838篇 |
2012年 | 7746篇 |
2011年 | 8143篇 |
2010年 | 7104篇 |
2009年 | 6714篇 |
2008年 | 6547篇 |
2007年 | 6150篇 |
2006年 | 5899篇 |
2005年 | 5167篇 |
2004年 | 3390篇 |
2003年 | 2867篇 |
2002年 | 2541篇 |
2001年 | 2361篇 |
2000年 | 2333篇 |
1999年 | 2340篇 |
1998年 | 1756篇 |
1997年 | 1493篇 |
1996年 | 1343篇 |
1995年 | 1165篇 |
1994年 | 968篇 |
1993年 | 673篇 |
1992年 | 533篇 |
1991年 | 410篇 |
1990年 | 366篇 |
1989年 | 266篇 |
1988年 | 207篇 |
1987年 | 130篇 |
1986年 | 134篇 |
1985年 | 71篇 |
1984年 | 50篇 |
1983年 | 28篇 |
1982年 | 43篇 |
1981年 | 28篇 |
1980年 | 24篇 |
1979年 | 14篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1959年 | 8篇 |
1951年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
The HUB-CI model is investigated in a telerobotic system in a client/server network to manage the lifecycle of engineering design and prototyping. The purpose of this platform is to support collaborative engineering design and proof of concept to enhance distributed team collaboration and resource utilization. The suggested platform is exemplified in two collaboration support tools and a physical prototyping platform. Structured Co-Insight Management is developed to support innovative idea exchanges and the consensus decision-making during the design process. Conflict/error detection management helps preventing conflicts and errors during the lifecycle of design and development. Physical collaboration over the network occurs when a team controls the telerobot operation during prototyping and testing in design cycles. A pilot system is implemented with a group project for the design of an electronic circuit (including both hardware and software designs). The functional assessment method is used to compare this platform to other collaborative design tools. The system presented offers unique qualitative advantages as an integrated collaboration support system. 相似文献
105.
Jiuxin Jiang Bo Zhu Peiling Wang Weiwu Chen Dongsheng Yan Hanrui Zhuang Yibing Cheng 《Journal of the American Ceramic Society》2005,88(4):950-953
The Pr α-sialon powders prepared by self-propagating high-temperature synthesis (SHS), consisting of 55 wt% Pr α-sialon and 45 wt% of β-sialon (abbreviated as α' and β'), were hot-pressed at 1800°C for 1 h. The results showed that Pr α' phase would transfer to β' with the appearance of JEM phase (Pr(Si6− z Al z )(N10− z O z )) after sintering, thus resulting in the increase of β' phase to 86 wt%. The addition of Y2 O3 into SHS-ed Pr α' powders as the starting materials restrains the transformation of α' to β' and prevents the formation of JEM phase as well. The nucleation mechanism of Pr α' grain during hot-pressing was investigated in terms of transmission electron microscope and energy-dispersive spectrometer analysis. Two nucleation modes of Pr α' grains were found, i.e., nucleating on the undissolved Pr α' grains and on the nuclei of (Pr, Y) α' grains precipitated from liquid phase. 相似文献
106.
107.
0 前言
湖南韶峰水泥集团有限公司规格为φ2.5 m×3.9 m的风扫式煤磨配套的MDC89-7袋式除尘器于1993年投用,经十多年的生产应用,其导流板及风道损坏达80%左右;外壳、主风道因烧袋和腐蚀,严重变形且花板变得很薄;反吹风道变形穿孔,提升阀密封不严,导致清灰时风量流失严重,运行阻力增加,系统产量降低,且系统中含氧量增加,带来安全隐患;除尘效率下降、污染严重,粉尘排放浓度高达1 g/m3;系统能耗高,且维修强度大(每个滤袋重50kg,每次换袋需12人)且费用高.为此,该公司于2004年4月对该煤磨除尘器进行技术改造,取得了明显的效果. 相似文献
108.
Three-dimensionally ordered long-range macroporous carbon structures were prepared using commercially available phenolic resin
by utilizing sacrificial colloidal silica crystalline arrays as templates that were subsequently removed by HF etching after
pyrolysis in an argon atmosphere. SEM, TEM, and BET were employed to characterize the morphology and the surface area of the
porous carbon structures. The pore size (150–1000 nm) and BET surface area, which reflect pore volume (298.6 m2/g (1.32 cm3/g) ∼ 93.7 m2/g (0.12 cm3/g)), of the macroporous carbon structures produced were approximately proportional to the size (150–1000 nm) of the sacrificial
silica sphere templates used (annealing temp. 550°C). The achieved 550 nm porous carbon structures were examined to function
as potential catalyst carriers and were successfully impregnated with Ag or Pt-Ru on their inner walls after borohydride reduction
at room temperature. In addition, porous carbon patterns were fabricated using the ‘micromolding in capillary’ technique,
which has potential applications in the microreaction technology. 相似文献
109.
孙浩 《计算机与数字工程》2014,(3):433-434
介绍了应用线性矩阵不等式(LMI)解决一类时滞系统H∞控制问题,给出了基于Lyapunov第二法的H∞稳定条件,通过求解锥补线性化问题,得到相应的控制器,使得闭环系统稳定且满足H∞性能指标.并通过实例给出了仿真结果. 相似文献
110.
生物柴油与普通柴油任意比例互溶的混合物可以代替石化柴油供内燃机使用,为了使得这种混合物在内燃机应用中达到好的动力性和排放效果,就需要研究不同比例的生物柴油—柴油混合物的雾化效果。利用数字图像处理的方法对生物柴油-柴油混合物雾化图像进行处理,获得了单位面积内雾化粒度的数量和平均直径,处理速度快捷、准确,减少了传统人工方法分析的主观性和较高的失误率。 相似文献