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621.
炉盖排风罩在精炼炉除尘系统中的应用 总被引:1,自引:0,他引:1
介绍了炉盖排风罩在涟钢一炼钢厂 2× 30t钢包精炼炉除尘系统中的应用 ,并将其与传统的炉内捕集式炉盖进行分析比较 ,说明其优越性和推广价值。由于该项技术的使用 ,涟钢一炼钢厂精炼炉除尘系统从根本上解决了环保与生产之间的矛盾 ,运行结果表明 ,各项技术指标均可达到国家标准 相似文献
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623.
624.
建立了过氯乙烯滤膜采集环境空气中镉,微波消解滤膜、硝酸镁溶液作为基体改进剂,石墨炉原子吸收光谱法测定镉的方法。本方法前处理操作过程简单、省时、酸用量少、环境污染小,方法的灵敏度和准确度都有很大的提高。当采样体积为6000L,镉的最低检出质量浓度为0.0008mg/m^3。 相似文献
625.
《Journal of Manufacturing Processes》2014,16(1):26-55
Welding is a fabrication process to join two different materials. Among the many welding processes, the arc and laser welding processes are the most widely used. Great effort is required to understand the physical phenomena of arc and laser welding due to the complex behaviors which include liquid phase, solid phase and, gas phase. So it is necessary to conduct numerical simulation to understand the detailed procedures of welding. This paper will present the various numerical simulation methods of the arc welding processes such as arc plasma, gas tungsten arc welding, gas metal arc welding, laser welding, and laser–arc hybrid welding. These simulations are conducted by the finite element method, finite differential method and volume of fluid method to describe and analyze the various welding processes. 相似文献
626.
《Journal of Manufacturing Processes》2014,16(4):563-572
Effects of switching over from gas tungsten arc welding (GTAW) to pulsed current gas tungsten arc welding (PCGTAW) on the quality of joints produced in Hastelloy C-276 material were investigated. Welding was carried out both by autogenous mode and using ERNiCrMo-3 filler wire. Microstructures of weld joints produced with and without current pulsing were studied using optical and scanning electron microscopy. Microsegregation occurring in GTAW and PCGTAW joints was investigated using energy dispersive X-ray spectroscopy (EDS). Strength and ductility of weld joints produced with and without pulsing were evaluated. The results show that pulsing results in refined microstructure, reduced microsegregation and improved strength of weld joints. Secondary phase(s) noticed in GTA weldments were found to be absent in PCGTA weldments. Autogenous PCGTA weldments were found to be the best in terms of: (i) freedom from microsegregation, (ii) strength and (iii) freedom from unwanted secondary phases. 相似文献
627.
通过研究实际操作中汽包水位的变化趋势,对锅炉灭火后水位变化情况进行分析,得出锅炉灭火后汽包水位升降的3个阶段,指导实际操作。 相似文献
628.
通过对石墨炉原子吸收法、电感耦合等离子体质谱法、比色法测定水中钴的方法性能进行比对研究,分析了各自的优缺点,为实验人员对钴分析方法选择提供良好的技术依据。当测定钴含量为5.00%~99.5μg/L时,石墨炉原子吸收法的RSD为2.6%~3.9%,加标回收率为93.5%~101.4%;ICP-MS法的RSD为2.0%~3.3%,加标回收率为95.6%~97.1%;5-CI-PADAB光度法的RSD为3.8%~4.8%,加标回收率为91.6%~103.8%。 相似文献
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630.
In the present work, metal-cored arc welding process was used for joining of modified 9Cr-1Mo (P91) steel. Metal-cored arc welding process is characterized by high productivity, slag-free process, defect-free weldments that can be produced with ease, and good weldability. Toughness is essential in welds of P91 steel during hydro-testing of vessels. There is a minimum required toughness of 47 J for welds that has to be met as per the EN1557:1997 specification. In the present study, welds were completed using two kinds of shielding gases, each composition being 80% Argon + 20% CO2, and pure argon respectively. Microstructural characterization and toughness evaluation of welds were done in the as – weld, PWHT at 760 °C – 2 h and PWHT at 760 °C – 5 h conditions. The pure argon shielded welds (‘A2’ and ‘B2’) have higher toughness than 80% argon + 20% CO2 shielded welds (‘A1’ and ‘B1’). Pure argon shielded welds show less microinclusion content with low volume fraction of δ-ferrite (<2%) phase. Themo-calc windows (TCW) was used for the prediction of equilibrium critical transformation points for the composition of the welds studied. With increase in post-weld heat treatment (PWHT) duration from 2 h to 5 h, there was increase in toughness of welds above 47 J. Using metal-cored arc welding process, it was possible to achieve the required toughness of more than 47 J after PWHT at 760 °C – 2 h in P91 steel welds. 相似文献