全文获取类型
收费全文 | 24014篇 |
免费 | 2942篇 |
国内免费 | 1841篇 |
专业分类
电工技术 | 2089篇 |
综合类 | 2648篇 |
化学工业 | 3163篇 |
金属工艺 | 1753篇 |
机械仪表 | 1589篇 |
建筑科学 | 1919篇 |
矿业工程 | 1145篇 |
能源动力 | 676篇 |
轻工业 | 2916篇 |
水利工程 | 838篇 |
石油天然气 | 902篇 |
武器工业 | 456篇 |
无线电 | 2399篇 |
一般工业技术 | 1790篇 |
冶金工业 | 1105篇 |
原子能技术 | 403篇 |
自动化技术 | 3006篇 |
出版年
2024年 | 165篇 |
2023年 | 493篇 |
2022年 | 1091篇 |
2021年 | 1350篇 |
2020年 | 948篇 |
2019年 | 620篇 |
2018年 | 699篇 |
2017年 | 821篇 |
2016年 | 702篇 |
2015年 | 1134篇 |
2014年 | 1422篇 |
2013年 | 1701篇 |
2012年 | 2108篇 |
2011年 | 2066篇 |
2010年 | 2024篇 |
2009年 | 1915篇 |
2008年 | 1915篇 |
2007年 | 1858篇 |
2006年 | 1494篇 |
2005年 | 1087篇 |
2004年 | 785篇 |
2003年 | 585篇 |
2002年 | 527篇 |
2001年 | 488篇 |
2000年 | 410篇 |
1999年 | 152篇 |
1998年 | 38篇 |
1997年 | 27篇 |
1996年 | 28篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 15篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 9篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1965年 | 3篇 |
1959年 | 5篇 |
1951年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
现代学徒制是一项深化产教融合、校企合作的育人机制,是创新技术技能人才的现代培养模式.山西铁道职业技术学院与山西安泰控股集团有限公司深度合作开展山西省现代学徒制试点项目,合作目的之一是培养企业煤化工专业人才.学校教师结合学生(员工)在企业车间岗位上的技能知识,系统地讲授煤化工专业课程"煤质分析及煤化工产品检验"理论知识,同时针对企业员工日常学习思想政治知识较少的实际,润物细无声地加入思政元素,实现专业知识与实践技能相结合,技能知识与思政教育相融合,真正培养知识型、技能型、创新型高素质技能人才,努力构建职业教育产业发展命运共同体. 相似文献
3.
4.
在无线传感器网络中,大量感知数据汇集到sink节点的采集方法会导致sink节点附近的节点能量耗尽,造成能量空洞。针对该问题,利用移动的sink节点进行数据收集是一种解决方法,其中移动sink的路径规划成为一个重要的问题。提出了一个移动sink路径规划算法,将无线传感器中随机分布的节点划分为不同的子区域,寻找sink节点移动的最佳转向点,最终得到最优的移动路径,以实现无线传感器网络生命周期最大化。仿真实验表明,与现有方案相比,该算法能显著延长网络的生命周期。 相似文献
5.
6.
Anti-washout and tissue adhesion properties are essential for the clinical application of injectable bone materials. In this study, we prepared calcium phosphate cement (CPC) with anti-washout and tissue adhesion properties and attempted to build covalent bonds between CPC and the amino groups in bone tissue under a self-regulating pH system in the CPC (acidic to basic). The results of push-out tests demonstrated that a significant enhancement (from 6.42 ± 0.76 N to 61.5 ± 4.09 N) in tissue adhesion was obtained with the addition of 6% (w/w) oxidized sodium alginate (OSA) in CPC. The FTIR, XRD, anti-washout test, XPS, pH test, and SEM results suggested that the synergistic effect of OSA-citric acid (CA) led to the formation of a three-dimensional gel network structure in the CPC, and the Schiff base reaction between aldehyde and amino groups induced adhesion between CPC and the bone tissue. Further, the addition of less OSA had no significant negative effect on the hydration properties of CPC. Our work aims to promote the development of injectable bone material in clinical applications. 相似文献
7.
8.
ZHAO Pengfei TIAN Yuming LIU Aiping KONG Xiangchen CHAI Yuesheng LI Zhangang BAI Pinbo 《中国耐火材料》2015,(2):36-41
Based on the needs of the market,a new 52 MPa medium-density and high-strength ceramic proppant was prepared by adopting third grade bauxite and clay as raw materials and using the solid phase sintering method,and the effect of the firing temperature on the microstructure,phase composition and mechanical properties of the ceramic proppant was studied. The broken resistance mechanism of this ceramic proppant was also discussed. The results show that the main phases of the prepared ceramic proppant are mullite and corundum; the broken rates are 3. 92% and 7. 21% under 52 MPa and69 MPa,respectively. 相似文献
9.
This paper discusses the compressive performance of perforated brick masonry after fire exposure. Compressive strength tests of the mortar, clay perforated brick, and perforated brick masonry specimens were performed in accordance with ISO834 fire tests of different durations. The temperature distribution of the masonry materials and specimens was simulated using the finite element software ABAQUS, with the thermal parameters of masonry materials recommended by European standard Eurocode 6 and related literature. The compressive strength reduction factors of mortar and clay perforated brick exposed to different fire durations were calculated via the layered method suggested by European standard Eurocode 1. In addition, the compressive strength reduction factors after cooldown were obtained from the experimental data of the masonry materials, and by considering further reductions in the compressive strength after cooling from high temperatures. Experimental data of the masonry specimens were compared with the numerical results obtained using the reduction factors proposed in this work. The comparison revealed an overall acceptable approximation. Thus, the method presented in this paper can be used to evaluate the residual capacity of masonry structures after fire. 相似文献
10.
通过对粉煤灰砖抗折强度测量结果不确定度的评定,分析出影响试验结果的各种因素,为提高检测水平和精确度提供指导。 相似文献