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991.
本文研究了中国东北地区不同纬度梯度农田土壤Olsen-P在0~100cm剖面中的分布特征。结果表明,除公主岭和大石桥外,其他各点土壤Olsen-P含量在0~20cm土层较高,20~40cm土层迅速下降,40~100cm各土层又逐渐升高,但底层要远低于表层。不同纬度梯度下各点0~20cm土层Olsen-P含量为暗棕壤>黑土>棕壤,高纬度地点Olsen-P含量具有高于低纬度地点的趋势;20~100cm各土层Olsen-P含量总体表现为黑土和暗棕壤相对较高,棕壤区偏低,没有明显的纬度分异现象。施肥等农田管理措施对0~20cm土壤Olsen-P含量有明显影响,其他土层Olsen-P含量可能主要受磷素运移特点和成土母质等因素影响。 相似文献
992.
Heartwin Amaladhas Pushpadass Govindarajan Suresh Babu Robert W. Weber Milford A. Hanna 《Packaging Technology and Science》2008,21(3):171-183
Starch‐based loose‐fill packaging foams were made in a single‐screw laboratory‐scale extruder. Corn starch was blended with polystyrene in the ratio of 70 : 30 and extruded into foams using talc and polycarbonate as additives. Extrusions were carried out at moisture contents of 16, 18 and 20% (dry basis), and at barrel temperatures of 140 and 160°C. The influences of extrusion temperature, moisture content of starch, talc and polycarbonate on the radial expansion and other selected physical properties of starch foams were investigated. The effects of moisture and talc contents on the radial expansion of foams were found to be critical, while the role of temperature was close to significant. The expansion ratio increased when the moisture content was increased from 16 to 18%, and then decreased when moisture content was increased to 20%. In general, the expansion ratios of foams were higher at 160°C as compared to 140°C. Although polycarbonate mixed well with the starch–polystyrene melt, it was not effective as a structural and anti‐shrinking agent, and it did not contribute to the radial expansion. In general, the bulk densities and unit densities of the starch foams decreased as the moisture content and extrusion temperature increased. Scanning electron microscope images showed that the addition of talc yielded foams with smaller‐sized cells, with less expansion of the foam melt, and thus a higher density. X‐ray diffractograms revealed that the crystallinity of starch foams increased post‐extrusion, and there was adequate dispersion of the starch and polystyrene polymers to make the foam water‐resistant. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
993.
994.
研究了3个直接黑色染料的应用性能,与C.I.直接黑38进行了比较,结果显示:这些染料在上染曲线、染色深度、染色工艺、可见光谱和染料色光与C.I.直接黑38近似,在耐光和耐洗牢度方面相当或优于C.I.直接黑38。 相似文献
995.
Viorel Gheorghe Ungureanu and Adrian Stanica 《Lakes & Reservoirs: Research and Management》2000,5(2):111-115
The Romanian Black Sea coastal zone is divided into two main sectors. Sediment characteristics and general transport patterns are presented for each of them. The human activities influencing the beaches’ evolution are depicted and the present‐day impact described. 相似文献
996.
PVDF合金/炭黑体系在自控温加热电缆中的应用 总被引:2,自引:0,他引:2
本文介绍用聚偏氟乙烯(PVDF)—特种含氟橡胶合金/炭黑(CB)导电复合体系制作自控温加热电缆以及该电缆的各种性能。通过在220V,50Hz交流电压下连续通电3000h的长期运行实验、通断电500次的循环实验以及发热功率与环境温度关系实验,并借助于广角X射线衍射等手段,来分析其运行前后的PTC曲线及结晶行为,证实了该自控加热电缆的各种性能完全符合要求,用该体系来生产高温品级的自控温加热电缆是安全可行的,可以投入大规模生产 相似文献
997.
Zia-ur-Rehman Abdul Majeed Salariya 《International Journal of Food Science & Technology》2005,40(7):695-700
The effects of hydrothermal processing on antinutrients and the protein and starch digestibility of black grams, chick peas, lentils and red and white kidney beans was investigated. The tannins and phytic acid contents in these five food legumes ranged from 770 to 1100 and 970 to 1440 mg/100 g, respectively, whereas protein and starch digestibility of the raw food legumes was found to be from 33.8 to 37.6 and 36.8 to 42.0%, respectively. A reduction in the level of these antinutrients, along with an improvement in protein and starch digestibility, was observed after cooking. The tannins and phytic acid contents were reduced by 33.1–45.7 and 28.0–51.6%, respectively, because of the use of different hydrothermal treatments at 100, 121 and 128 °C. Maximum improvement in protein digestibility (95.7–105.1%) and starch digestibility (116.7–137.7%) was observed on cooking at 121 °C for 10 min. However, cooking in boiling water resulted in improvement in protein and starch digestibility of the food legumes by 86.9–93.3 and 84.0–90.4%, respectively. 相似文献
998.
David M. Mahli Jon M. Wegner J. Edward Glass Daniel G. Phillips 《Journal of Coatings Technology and Research》2005,2(8):635-647
A matrix of coating variables, nonassociative versus associative thickeners, different latex median particle sizes, individual
surfactants and colorants [carbon black (CB), red, and yellow pigments], was examined for their influence on variances in
coatings rheology and color development. Within the different coating groups, the variable of interest in this study was the
surfactant added to the colorant formulation. In all three colorant formulations, sodium dodecyl sulfate (an anionic surfactant)
provided poorer color development (CD) than in applied formulations containing an equivalent nonylphenol oxyethylene (EO)
surfactant. In CB formulations, nonionic surfactants with higher EO content provide improved color development at low (2 mM)
concentrations, but near equality in CD is achieved with low EO surfactants at higher concentrations. In contrast to CB formulations,
red and yellow colorants exhibit good color development with high EO content nonionic surfactants only at low nonionic surfactants
concentrations. This variance appears to be related to the interactions of surfactants with inorganic pigments (talc and laponite)
in the colorant formulation.
The coating’s rheology is related to latex, thickeners, and surfactant components of the paint, as has been noted in previous
studies, but not to the nature of the color pigment. The viscosity of the hydroxyethyl cellulose (nonassociative type) and
HEUR (associative type) thickened paint decreased with colorant addition due to dilution effects. There were no unusual deviations
with the NP(EO)x surfactants, except when a large hydrophobe nonionic surfactant [e.g., C18H37(EO)100] is added. In HEC thickened coatings, the viscosity decreases when C18H37-(EO)100 is in the colorant due to that surfactant inhibiting depletion flocculation. In the C18H37(EO)100 coatings containing the HEUR thickener, significant increases in viscosity were observed, above the dilution values observed
with the colorant addition. This is related to the viscosity maximum in the low concentration of HEUR with the C18H37(EO)100 surfactant. Color development is independent of the viscosity profile of the coating.
Presented in part at the 81st Annual Meeting of the Federation of Societies for Coatings Technology, November 13–14, 2003
in Philadelphia, PA. 相似文献
999.
1000.
黑土区土壤肥力一直是人们关心的问题。通过选择在黑土区典型县份-德惠市的调查表明,耕地土壤有机质、全氮、有效磷与1980年相比较,分别增加了3.2g kg-11,0.11 g kg-1和5.70 mg kg-1,但有效钾下降了33.3 mg kg-1。土壤中有机质2003年盈余量48.7kg hm-2,氮15.07 kg hm-2,磷25.35 kg hm-2;钾亏损量170.62 kg hm-2。笔者认为,单纯从土壤营养管理角度看,目前黑土区耕地土壤肥力状况似乎没有想象的那么坏。但已有的研究也表明,黑土区耕地肥力的变化与现行的耕作制度有很大的关系。 相似文献