全文获取类型
收费全文 | 32494篇 |
免费 | 2708篇 |
国内免费 | 1196篇 |
专业分类
电工技术 | 1682篇 |
技术理论 | 6篇 |
综合类 | 2197篇 |
化学工业 | 2829篇 |
金属工艺 | 261篇 |
机械仪表 | 1066篇 |
建筑科学 | 4709篇 |
矿业工程 | 2366篇 |
能源动力 | 895篇 |
轻工业 | 9064篇 |
水利工程 | 2362篇 |
石油天然气 | 1250篇 |
武器工业 | 331篇 |
无线电 | 834篇 |
一般工业技术 | 2215篇 |
冶金工业 | 809篇 |
原子能技术 | 975篇 |
自动化技术 | 2547篇 |
出版年
2024年 | 112篇 |
2023年 | 466篇 |
2022年 | 987篇 |
2021年 | 1333篇 |
2020年 | 1315篇 |
2019年 | 978篇 |
2018年 | 937篇 |
2017年 | 1037篇 |
2016年 | 1244篇 |
2015年 | 1300篇 |
2014年 | 2638篇 |
2013年 | 2182篇 |
2012年 | 2965篇 |
2011年 | 2624篇 |
2010年 | 1943篇 |
2009年 | 1766篇 |
2008年 | 1653篇 |
2007年 | 2037篇 |
2006年 | 1797篇 |
2005年 | 1469篇 |
2004年 | 1117篇 |
2003年 | 1046篇 |
2002年 | 748篇 |
2001年 | 541篇 |
2000年 | 449篇 |
1999年 | 330篇 |
1998年 | 238篇 |
1997年 | 208篇 |
1996年 | 146篇 |
1995年 | 140篇 |
1994年 | 112篇 |
1993年 | 113篇 |
1992年 | 88篇 |
1991年 | 54篇 |
1990年 | 45篇 |
1989年 | 48篇 |
1988年 | 52篇 |
1987年 | 26篇 |
1986年 | 17篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1973年 | 3篇 |
1959年 | 6篇 |
1955年 | 2篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
如今我国信息化技术全面发展,尤其对于工程测量工作领域来讲,不管是在工程建设和管理方面都产生不小的支撑引导效用。由此,笔者具体结合如今工程建设信息化测绘核心任何以及设备布置细节,进行结构整体安全管理周期和周边地理空间信息技术发展能效整理解析,试图将工程测量最新发展机遇和技术挑战问题处理完全。希望能够借此为日后一定时期范围内相关工程测量规划主体提供合理指导性建议内容,最终为我国各类工程事业可持续发展前景绽放奠定深刻适应基础。 相似文献
92.
多级孔HZSM-5分子筛催化快速热解生物质制芳烃 总被引:1,自引:0,他引:1
采用酸和/或碱处理法制备了一系列多级孔HZSM-5分子筛,采用XRD、N2吸附、XRF、TEM、27Al MAS NMR和NH3-TPD等表征手段对其孔道结构和酸性进行表征。表征结果表明,采用碱处理方法,可获得孔径集中于3~6 nm的介孔结构,通过改变酸、碱处理次序,可调变酸中心数量和强酸/总酸中心比例。在Py-GC/MS装置上,以纤维素和水稻秸秆为原料,研究多级孔分子筛结构对催化快速热解(CFP)制芳烃反应的影响。反应评价结果表明,同商品级HZSM-5相比,采用先碱后酸处理获得的多级孔HZSM-5分子筛(HZ-OH/H),可将纤维素CFP芳烃碳产率由32.3%提高至43.6%,可将水稻秸秆CFP芳烃碳产率由23.0%提高至30.8%。多级孔HZ-OH/H分子筛的孔道结构和酸中心分布特征,对开发应用于生物质制芳烃的高效工业催化剂具有借鉴意义。 相似文献
93.
94.
95.
Iratxe Perez-Arnedo María J. Cantalejo Alba Martínez-Laorden Elena Gonzalez-Fandos 《International Journal of Food Science & Technology》2021,56(4):1855-1864
Microbiological contamination of chicken meat depends on the conditions under which the animals are reared, slaughtered and processed. The aim of this study was to determine the influence of farm origin and processing stages at slaughterhouse on the microbial safety and quality of chicken. Samples of chicken carcasses from three different farms were taken from a slaughterhouse. Mesophiles, Escherichia coli, coagulase positive Staphylococcci counts, presence of Listeria monocytogenes,Campylobacter and Salmonella were determined at five sampling points: after defeathering, after evisceration, after washing, after chilling and after cutting. Chilling reduced log numbers of mesophiles, coagulase positive Staphylococci and E. coli by 0.85, 1.52 and 2.2 log units, respectively. Salmonella was not detected after chilling. High prevalence of Campylobacter spp was observed at all the stages ranging between 84% and 100%. L. monocytogenes was not detected in chicken carcasses after defeathering. However, it was detected after evisceration and after washing and chilling. The most critical stage for L. monocytogenes contamination was the portioning operation, the prevalence in breast and legs being 88% and 84%, respectively. 相似文献
96.
E.-A. Reinecke K. Takenaka H. Ono T. Kita M. Taniguchi Y. Nishihata R. Hino H. Tanaka 《International Journal of Hydrogen Energy》2021,46(23):12511-12521
The safe decommissioning as well as decontamination of the radioactive waste resulting from the nuclear accident in Fukushima Daiichi represents a huge task for the next decade. At present, research and development on long-term safe storage containers has become an urgent task with international cooperation in Japan. One challenge is the generation of hydrogen and oxygen in significant amounts by means of radiolysis inside the containers, as the nuclear waste contains a large portion of sea water. The generation of radiolysis gases may lead to a significant pressure build-up inside the containers and to the formation of flammable gases with the risk of ignition and the loss of integrity.In the framework of the project “R&D on technology for reducing concentration of flammable gases generated in long-term waste storage containers” funded by the Japanese Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), the potential application of catalytic recombiner devices inside the storage containers is investigated. In this context, a suitable catalyst based on the so-called intelligent automotive catalyst for use in a recombiner is under consideration. The catalyst is originally developed and mass-produced for automotive exhaust gas purification, and is characterized by having a self-healing function of precious metals (Pd, Pt and Rh) dissolved as a solid solution in the perovskite type oxides. The basic features of this catalyst have been tested in an experimental program. The test series in the REKO-4 facility has revealed the basic characteristics of the catalyst required for designing the recombiner system. 相似文献
97.
双层复合衬砌结构是一种新型隧洞衬砌结构型式,其外衬承受外部水土压力,内衬承受内水压力,体现了"结构联合、功能独立"的新型输水隧洞设计理念,目前该衬砌型式已成功应用到我国北方某输水工程中,如何确定双层复合衬砌隧洞安全预警监控指标是工程运行管理的重点和难点。本文基于以往研究成果,提出了工程结构监控指标及监控阈值确定的统一技术路径;根据双层复合衬砌结构受力特点,开展可能破坏模式分析;基于破坏模式与监测量的敏感性分析,提出层间渗压作为双层复合衬砌隧洞结构核心监控指标,内衬处的钢筋计测值以及外衬处的测缝计测值作为辅助监控指标,为双层复合衬砌隧洞安全运行提供借鉴和参考。 相似文献
98.
Thapakorn Chumphon Kanjana Pangjit Saran Promsai 《International Journal of Food Science & Technology》2021,56(5):2182-2192
This study found that the isolated probiotics Lactobacillus paracasei KUKPS6201, L. acidophilus KUKPS6107, L. reuteri KUKPS6103, L. rhamnosus KUKPS6007, L. salivarius KUKPS6202, Bacillus coagulans KPSTF02 and Saccharomyces boulardii KUKPS6005 had high potential for probiotic properties. All strains had antibacterial activity and high antioxidant activity of 1.654 ± 0.017 mg Trolox mL−1 probiotic extract. The selected strains could survive in a simulated gastrointestinal tract under anaerobic conditions and showed no haemolytic activity. Furthermore, the probiotic strains were strongly auto-aggregated and also showed co-aggregated ability with pathogenic bacteria. The probiotic microorganisms demonstrated high ability to adhere to Thai-pigmented rice grains. The results of analysis of these probiotics showed that Riceberry rice bran oil was an excellent prebiotic. A synbiotic product containing Thai-pigmented rice grains (cultivar Riceberry, Luem Pua and Black Jasmine) and rice bran oil was produced. After 8 weeks of storage, the viability of the probiotics in terms of multistrains was 7.36 ± 0.04 log CFU g–1 (85.78% survival rate). Microbiological safety testing indicated that the amounts of contaminants were acceptable. This study provided the first scientific report on the feasibility of applying Thai-pigment rice, rice bran oil and mixed-culture probiotics as a novel functional synbiotic product. 相似文献
99.
100.
《International Journal of Hydrogen Energy》2022,47(6):4222-4235
Quantitative Risk Assessment (QRA) supports the development of risk-informed safety codes and standards which are employed to enable the safe deployment of hydrogen technologies essential to decarbonize the transportation sector. System reliability data is a necessary input for rigorous QRA. The lack of reliability data for bulk liquid hydrogen (LH2) storage systems located on site at fueling stations limits the use of QRAs. In turn, this hinders the ability to develop the necessary safety codes and standards that enable worldwide deployment of these stations. Through a QRA-based analysis of a LH2 storage system, this work focuses on identifying relevant scenario and probability data currently available and ascertaining future data collection requirements regarding risks specific to liquid hydrogen releases. The work developed consists of the analysis of a general bulk LH2 storage system design located at a hydrogen fueling station. Failure Mode and Effect Analysis (FMEA) and traditional QRA modeling tools such as Event Sequence Diagrams (ESD) and Fault Tree Analysis (FTA) are employed to identify, rank, and model risk scenarios related to the release of LH2. Based on this analysis, scenario and reliability data needs to add LH2-related components to QRA are identified with the purpose of improving the future safety and risk assessment of these systems. 相似文献