全文获取类型
收费全文 | 99366篇 |
免费 | 5039篇 |
国内免费 | 4994篇 |
专业分类
电工技术 | 4553篇 |
技术理论 | 6篇 |
综合类 | 9846篇 |
化学工业 | 14164篇 |
金属工艺 | 5826篇 |
机械仪表 | 3444篇 |
建筑科学 | 5215篇 |
矿业工程 | 1724篇 |
能源动力 | 2926篇 |
轻工业 | 6457篇 |
水利工程 | 2251篇 |
石油天然气 | 4557篇 |
武器工业 | 770篇 |
无线电 | 7629篇 |
一般工业技术 | 14709篇 |
冶金工业 | 3468篇 |
原子能技术 | 2280篇 |
自动化技术 | 19574篇 |
出版年
2024年 | 186篇 |
2023年 | 399篇 |
2022年 | 806篇 |
2021年 | 886篇 |
2020年 | 1301篇 |
2019年 | 1235篇 |
2018年 | 1318篇 |
2017年 | 1239篇 |
2016年 | 1830篇 |
2015年 | 2510篇 |
2014年 | 4517篇 |
2013年 | 5276篇 |
2012年 | 4633篇 |
2011年 | 5329篇 |
2010年 | 4469篇 |
2009年 | 5895篇 |
2008年 | 5862篇 |
2007年 | 6283篇 |
2006年 | 5781篇 |
2005年 | 4873篇 |
2004年 | 4224篇 |
2003年 | 4056篇 |
2002年 | 4085篇 |
2001年 | 3081篇 |
2000年 | 3374篇 |
1999年 | 3117篇 |
1998年 | 2609篇 |
1997年 | 2473篇 |
1996年 | 2653篇 |
1995年 | 2734篇 |
1994年 | 2483篇 |
1993年 | 1529篇 |
1992年 | 1545篇 |
1991年 | 1063篇 |
1990年 | 771篇 |
1989年 | 691篇 |
1988年 | 656篇 |
1987年 | 384篇 |
1986年 | 234篇 |
1985年 | 377篇 |
1984年 | 419篇 |
1983年 | 432篇 |
1982年 | 336篇 |
1981年 | 410篇 |
1980年 | 273篇 |
1979年 | 120篇 |
1978年 | 117篇 |
1977年 | 71篇 |
1976年 | 43篇 |
1975年 | 58篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
龙泉金矿在全泥氰化提金过程中产生含氰化物174.76mg/L的洗涤废水,通过碱式氯化法处理后,再由渣浆泵送入尾矿库进行自然净化作用,污水得到进一步净化,尾矿库溢流废水氰化物浓度低于0.5mg/L,废水排入小梅溪后,下游第一个居民取水点氰化物浓度低于0.004mg/L,达到了国家规定的标准。 相似文献
992.
993.
BBU集中化组网能够有效地提高无线网络资源利用率,加快网络建设速度,降低运营成本,动态地解决无线业务迁移问题。通过分析BBU基带池集中化的技术及其特性,结合网络建设实际应用,提出BBU集中化组网建议。 相似文献
994.
Molecular sieve properties of activated carbon fibers modified by cracking treatment with methane are studied herein. The effect of methane treatment on the porous texture of the samples has been studied while varying temperature and time. These materials have been evaluated for their selectivity during CO2 and CH4 separation; their uptakes have been compared with non-treated activated carbon fibers (studied previously), which were considered suitable to be used as molecular sieves. Kinetics of CO2 and CH4 uptake have also been investigated in this research. The treatment produced materials exhibiting fast kinetics and high selectivity during CO2 and CH4 separation; at the same time however, the CO2 uptake capacity was diminished. 相似文献
995.
996.
在酸性条件下,用Ag~ 沉淀氮三甲撑膦酸溶液中的Cl~-,然后以淀粉和KIO_3为指示剂,用标准I~-溶液滴定过量的Ag~ 。测定准确,方法灵敏,可靠和方便。克服了莫尔法和佛尔哈德法不适用于该测定体系的困难。 相似文献
997.
Daizo Kunii 《Chemical engineering science》1980,35(9):1887-1911
A general procedure is proposed for innovative research and development of gas-solid reactor systems, with a brief explanation of the significance of each step in the procedureBased upon the contacting mode between gas and solid phases, as well as the ways of supplying thermal energy to the reacting regions, various types of gas-solid reactor systems are classified by using tables of so called “matrix” form, for thermal cracking and gasification of heavy oils, gasification of coal, gasification of solid waste, calcination of limestone, clinkering of cement and reduction of iron ore.The importance of fundamental concepts is emphasized for successful research and development by presenting several examples; namely, calcination of limestone, thermal cracking of heavy oils and gasification of solid waste materials.In connection with the direction in which fundamental research should be oriented, four primary ways of thinking are proposed, which can be applied to obtain innovative ideas for further research and development in this field.One example of the author's practical experience was selected to show the role of the fundamental research in the course of large scale development. Finally the author outlines the role of chemical reaction engineering to innovate the novel gas-solid reactor systems which may be inevitable for simultaneous solution of the three big E's; namely, Energy, Environment and Economy. 相似文献
998.
On fibrous carbon materials, including activated carbon fibers, sorption capacity for heavy oils, less viscous A-grade and more viscous C-grade, was determined. Sorption capacity depended strongly on their bulk density; the correlation was the same as that found previously on exfoliated graphite and carbonized fir fibers. On carbon fiber felts, excellent recycling performance was observed, though sorption capacity was not so high as on exfoliated graphite and carbonized fir fibers. By filtration under suction, about 90% of sorbed A-grade heavy oil could be recovered and no decrease in sorption capacity was detected even after eight cycles. By washing with solvents, n-hexane for A- and C-grade oils and A-grade oil for C-grade oil, almost 100% recovery with no marked reduction in sorption capacity was found for each cycle. For the felts of PAN-based carbon fibers, rather severe operations for oil recovery, centrifugation and squeezing with twisting, could be applied without pronounced decreases in sorption capacity and recovery ratio. 相似文献
999.
结合实例剖析由产品结构、成型工艺和工艺装备等主要因素影响的复合夹层结构玻璃钢件和实体玻璃钢件在固化成型中的变形现象,并指出了预防变形的各相应有效措施。 相似文献
1000.
刘雨雄 《数码设计:surface》2014,(3):154-155
谈到吕佩尔兹几乎让人们不想到德国新表现主义。同时也不可避免要涉及到他作为杜塞尔多夫艺术学院的院长的成就。无论从艺术风格、生活方式以及表达方式,吕佩尔兹无可争议的作为当今现代德国艺术家中。在众多德国现代艺术家中.名声显赫。独领风骚。 相似文献