全文获取类型
收费全文 | 29601篇 |
免费 | 2794篇 |
国内免费 | 1322篇 |
专业分类
电工技术 | 1805篇 |
技术理论 | 4篇 |
综合类 | 2031篇 |
化学工业 | 4692篇 |
金属工艺 | 1825篇 |
机械仪表 | 2008篇 |
建筑科学 | 2409篇 |
矿业工程 | 898篇 |
能源动力 | 864篇 |
轻工业 | 2250篇 |
水利工程 | 562篇 |
石油天然气 | 2081篇 |
武器工业 | 249篇 |
无线电 | 3221篇 |
一般工业技术 | 3335篇 |
冶金工业 | 1326篇 |
原子能技术 | 347篇 |
自动化技术 | 3810篇 |
出版年
2024年 | 181篇 |
2023年 | 610篇 |
2022年 | 1086篇 |
2021年 | 1426篇 |
2020年 | 1174篇 |
2019年 | 867篇 |
2018年 | 955篇 |
2017年 | 1046篇 |
2016年 | 897篇 |
2015年 | 1306篇 |
2014年 | 1539篇 |
2013年 | 1751篇 |
2012年 | 1863篇 |
2011年 | 2061篇 |
2010年 | 1747篇 |
2009年 | 1597篇 |
2008年 | 1662篇 |
2007年 | 1539篇 |
2006年 | 1562篇 |
2005年 | 1346篇 |
2004年 | 860篇 |
2003年 | 829篇 |
2002年 | 884篇 |
2001年 | 783篇 |
2000年 | 662篇 |
1999年 | 747篇 |
1998年 | 530篇 |
1997年 | 442篇 |
1996年 | 392篇 |
1995年 | 334篇 |
1994年 | 270篇 |
1993年 | 182篇 |
1992年 | 152篇 |
1991年 | 96篇 |
1990年 | 89篇 |
1989年 | 69篇 |
1988年 | 42篇 |
1987年 | 41篇 |
1986年 | 26篇 |
1985年 | 21篇 |
1984年 | 9篇 |
1983年 | 9篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1959年 | 1篇 |
1953年 | 1篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
Xiaobiao Zhu Jinping Tian Lujun Chen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2012,87(1):123-129
BACKGROUND: In biological treatment of coking wastewater, phenol may decrease the treatment efficiency because of its high concentration and toxicity to microorganisms. Bioaugmentation has been regarded as a good improvement of the traditional biological treatment using isolated degrading strains. In this study, two phenol degrading strains, Pseudomonas sp. PCT01 and PTS02, were isolated and investigated for degradation ability and application to real coking wastewater treatment. RESULTS: Complete phenol degradation was achieved after 18 h inoculation in medium containing 229‐461 mg L?1 of phenol for both strains. The presence of phenol, pyridine and other compounds in mixed substrate or in coking wastewater prolonged the degradation to 20‐32 h with an initial phenol concentration of 160‐280 mg L?1. The study of degradation kinetics yielded a two‐stage model to describe the effect of the initial phenol concentration and inhibitory compounds on phenol degradation. The highest degradation rate constant of the second stage, 1.25 h?1 for PCT01 and 0.75 h?1 for PTS02, was obtained at low phenol concentration in a single substrate. CONCLUSION: It was found that both strains could degrade phenol effectively and maintain their phenol degradation ability in coking wastewater, and therefore could be used for bioaugmentation treatment of coking wastewater. Copyright © 2011 Society of Chemical Industry 相似文献
982.
Shaohai Fu Changsen Du Mingjun Zhang Anli Tian Xia Zhang 《Progress in Organic Coatings》2012,73(2-3):149-154
Polymer-encapsulated phthalocyanine blue pigment dispersion was prepared with a polymerizable dispersant by emulsion polymerization method, and the effect of preparation conditions on the particle size of dispersion was investigated. Dynamic light scattering measurement demonstrated that allyloxy nonyl-phenoxypropanolpolyoxyethyleneetherammonium sulfonate (ANPS) was suitable for phthalocyanine blue pigment modification. The polymer-encapsulated phthalocyanine blue pigment dispersion with the small particles was obtained when the mass ratio of ANPS to phthalocyanine blue pigment, styrene (St) to phthalocyanine blue pigment, and ammonium persulfate (APS) to St was about 0.2, 0.2, and 0.01, respectively. Transmission electron microscopy (TEM), Fourier transforms infrared spectra (FTIR) and thermogravimetric analyses (TGA) provided supporting evidences for the encapsulation of phthalocyanine blue pigment with the formed copolymer. The polymer-encapsulated phthalocyanine blue pigment dispersion showed excellent stabilities to freeze–thaw treatment and centrifugal force. 相似文献
983.
阐述了气候变化背景下用于确定室外计算干球温度的气象数据统计时长的方法。基于确定统计时长的两个基本原则,根据标准差方法和最优气候均态模型,分别确定室外计算干球温度最小统计时长和气象要素最优平均数,通过两者的对比选取室外计算干球温度统计时长。以天津为例进行分析,结果表明,天津地区基于ASHRAE方法的累积发生频率为0.4%,1.0%和2.0%干球温度的统计时长应取15年,累积发生频率为99.0%和99.6%干球温度的统计时长应取10年;基于中国方法的供暖室外计算温度、冬季空调室外计算温度和夏季空调室外计算干球温度的统计时长分别应取13,10和15年。 相似文献
984.
预制拼装属于一种现代化的桥梁施工技术,为进一步解决存在的各种技术问题,本文将在探讨如何选择和布置桥梁预制场的基础上,深入分析桥梁预制节段拼装技术的应用,以此总结出桥梁预制施工流程优化的建议措施。 相似文献
985.
介绍了近几年来不同形貌SBA-15材料的设计组装过程,叙述了在非离子嵌段共聚物模板剂下,陈化温度、搅拌速率、共表面活性剂和无机盐等因素对SBA-15介孔材料形貌的影响,及其合成机理。介绍了不同形貌SBA-15材料的应用现状。认为不同形貌的SBA-15介孔材料对催化、吸附分离等反应具有不同的影响,但是对于每一种反应,总有一种形貌的SBA-15的反应性能是最佳的;为使机械性能和水热稳定性能优良的具有二维六方介孔结构的SBA-15材料能更好地应用于各领域,继续研究不同形貌的SBA-15的设计组装过程对催化、吸附分离和燃料电池等领域具有深远的意义。 相似文献
986.
Hanyang Li Xuekun Li Chenchen Tian Xiangdong Yang Yun Zhang Xianli Liu Yiming Rong 《The International Journal of Advanced Manufacturing Technology》2017,90(1-4):199-209
Glossiness is an optical index representing the capacity of a surface to reflect light, which is vital criteria for components in need of esthetic appearance. To achieve the stringent glossiness requirement, sanding and polishing for smooth surface generation become the necessary material removal method. However, the intrinsic correlation of surface roughness and glossiness is still not clear. Small roughness value does not always guarantee perfect glossiness, and high surface glossiness does not always require extreme surface roughness perfection. In this paper, the surface topography features and glossiness conditions are analyzed for sanded and polished surfaces. And the surface glossiness is modeled and simulated for surfaces generated with non-Gaussian topography features manufactured by sanding and polishing. Finally, the critical surface topography parameters are identified to establish the correlation with the surface glossiness. 相似文献
987.
988.
As a practical solution to reduce the emission pollution and energy crisis, the research and development of HICE has been processed in several decades. The focus of this paper is trying to explore the new features of the combustion duration in HICE not only by engine experiment, but also by analysis of the physical properties of hydrogen, especially the obvious difference from that of gasoline. Firstly, the laminar flame speed difference between hydrogen and gasoline was studied and discussed. Secondly, a distinctive rule of combustion duration in HICE was discovered by analyzing the experiment data. Finally, as a key reference point to the HICE operation, a new characteristic of the location of 50% mixture combust up was proposed and analyzed, this will be helpful for the calibration of optimum ignition timing. 相似文献
989.
990.
近年来,车辆的主动安全研究已经引起广泛的关注。针对汽车主动安全中行人检测的需求,基于彩色差值模型算法,通过Gauss算法分割图像和kalman滤波预测目标在下一时间可能出现的活动区域,提出了一种基于运动趋势估计的行人检测算法。经仿真表明,该汽车动态目标检测算法可实现行人运动趋势的估算,具有较好的实时性、可靠性。 相似文献