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31.
Elcio C. Oliveira Rodrigo F. Calili Anderson L. S. Ferreira Alexandre A. Ferreira Soraya N. Sakalem Clarisse L. Torres 《Petroleum Science and Technology》2017,35(24):2241-2248
This paper discusses metrologically the best practice regarding the calibration curves applied to H2S mass fractions determination in natural gas by gas chromatography with sulfur chemiluminescence detection (GC-SCD). Three calibration curves were constructed by performing GC-SCD analysis of different H2S gas standard concentrations (from 3 mg kg?1 up to 500 mg kg?1). These experimental curves are better fitted by an unweighted quadratic calibration curve considering ANOVA approach compared to ASTM D5504-12. Despite this, the obtained results show that these two different calibration curve approaches (ASTM and ANOVA) lead to comparable results. Hence, there are no significant statistical differences between these two approaches based on the hypothesis test applied. However, the quadratic calibration curve presents measurement uncertainties of H2S mass fractions much lower than the ASTM approach. 相似文献
32.
焊接热循环对ASTM4130钢热影响区组织及韧性影响 总被引:3,自引:2,他引:1
采用金相、扫描电镜(SEM)和焊接热模拟方法,研究了不同峰值温度和焊接线能量对ASTM4130钢焊接热影响区(HAZ)显微组织、冲击韧性和断口形貌的影响.结果表明,ASTM4130钢热影响区除回火软化区外均发生脆化现象.当峰值温度为1200 ℃和1350℃时,由于晶粒粗大,且产生了贝氏体、未回火马氏体和M-A组元等非平衡组织,其冲击韧性损失达母材的94.5%,脆化现象最严重.当峰值温度为950℃,冲击韧性较低的原因是该区产生了未回火马氏体和块状铁素体.当峰值温度为800℃时,晶界附近碳化物聚集和不均匀分布,以及块状铁素体的存在,造成该区发生脆化.焊态下焊接线能量对ASTM4130钢粗晶区的冲击韧性影响较小. 相似文献
33.
介绍了ASTM标准中圆形拉伸试样主要部位的尺寸与要求。采用国产万能工具显微镜-投影法对试样在平行长度部位的锥度进行了测量。该方法简便易行,结果准确可靠,满足了标准要求,同时发挥了老设备的作用,保证了试样的加工精度。 相似文献
34.
35.
Studies have been conducted for the ternary mixture of motor spirit, diesel, and kerosene oil samples using artificial neural network (ANN). American standard for testing materials (ASTM) distillation data of samples were used for the evaluation of respective components. Results of such evaluation of the samples were found to comply well with experimental values. 相似文献
36.
The effect of the removal of work hardened surface layers from specimens of 2024-T4 aluminum alloy and AISI-4130 steel on their fatigue lives has been investigated. Specimens were fatigued at selected stress levels for a given number of cycles and the surface layer was removed followed by subsequent fatigue cycling. Results confirm that when a material is subjected to fatigue loading, damage accumulates in the surface layers in the form of work hardening. Removal of the surface layer brings the specimen back to its pre-fatigued condition. 相似文献
37.
本文对目前最常用的三种混凝土氯离子渗透试验方法ASTMC1202、NEL法和RCM法进行讨论,并分析了各自的优缺点。 相似文献
38.
39.
介绍了电站阀门用ASTM材料的压力温度等级的计算方法及常用高温高压电站阀门压力温度等级与磅级制阀门的关系 相似文献
40.
Comparison of methods to determine CTOD for SENB specimens in different strain hardening steels 下载免费PDF全文
W.L. Khor P. Moore H. Pisarski C. Brown 《Fatigue & Fracture of Engineering Materials & Structures》2018,41(3):551-564
Methods for determining crack tip opening displacement (CTOD) given in national and international standards are compared for steels with a range of strain hardening characteristics. Crack tip opening displacement measurements were made from single‐edge notched bend notches using a silicone rubber casting method. The finite element model produced good agreements with predictions of these CTOD measurements. The versatility of the finite element model enabled CTOD from the original crack tip and the 45° intercept method to be compared. The 45° CTOD generally underestimates the original crack tip CTOD, and is less useful for conditions with stable crack extension. Apart from the high strain hardening material, CTOD calculated using BS 7448‐1, WES 1108 (JWES), and ASTM E1820 was slightly lower than the values determined from silicone measurements and modelling, which is conservative. ASTM E1820 gave the largest underestimation of CTOD, whilst BS 7448‐1 may be unsuitable for higher strain hardening steels, where the standard predicts higher CTOD than measured from the replica. JWES gives the most consistent estimation of CTOD for steels with a wide range of strain hardening values. 相似文献