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71.
72.
Knowledge networks in new product development projects: A transactive memory perspective 总被引:6,自引:0,他引:6
Even though an individual's knowledge network is known to contribute to the effectiveness and efficiency of his or her work in groups, the way that network building occurs has not been carefully investigated. In our study, activities of new product development teams were analyzed to determine the antecedents and consequences on the transactive memory systems, the moderating affect of task complexity was also considered. We examined 69 new product development projects and found that team stability, team member familiarity, and interpersonal trust had a positive impact on the transactive memory system and also had a positive influence on team learning, speed-to-market, and new product success. Further, we found that the impact of the transactive memory system on team learning, speed-to-market, and new product success was higher when there was a higher task complexity. Theoretical and managerial implications of the study findings are discussed. 相似文献
73.
Hasan etin
zen Mehmet Bashan Cumali Keskin Zuhal Toker 《European Journal of Lipid Science and Technology》2004,106(1):68-70
The fatty acid compositions of flowering tops of Hypericum perforatum L. and Hypericum retusum Aucher (Guttiferae) were analyzed by gas chromatography and gas chromatography‐mass spectrometry. The major components were C16:0 (24.87%), C18:3 n‐3 (21.94%), 3‐OH‐C18:0 (18.46%) and 3‐OH‐C14:0 (14.22%) for H. perforatumL. and 3‐OH‐C14:0 (28.29%), C18:0 (16.47%) and C16:0 (14.17%) for H. retusum Aucher. Besides widespread plant fatty acids, 3‐hydroxy fatty acids, namely 3‐hydroxytetradecanoic acid (3‐OH‐C14:0) and 3‐hydroxyoctadecanoic acid (3‐OH‐C18:0) were also obtained. 相似文献
74.
Utilization of fly ash and ground granulated blast furnace slag as an alternative silica source in reactive powder concrete 总被引:1,自引:0,他引:1
Reactive powder concrete (RPC) is an ultra high strength cement-based material. Cement and silica fume (SF) content of RPC are generally rather high compared to the conventional concrete. The aim of this study is to decrease the cement and SF content of RPC using with fly ash (FA) and/or ground granulated blast furnace slag (GGBFS). The effect of these mineral admixtures on compressive strength of RPC has been investigated under autoclave curing. In the first stage, the effect of autoclave time and SF content on compressive strength was determined. In the second stage, SF was gradually decreased and cement was replaced with FA and/or GGBFS at different proportions. The microstructure was investigated by scanning electron microscope (SEM). Test results indicate that, the utilization of FA and/or GGBFS in RPC is possible without significant mechanical performance loss. SEM micrographs revealed the tobermorite having different morphology. 相似文献
75.
GIS based statistical and physical approaches to landslide susceptibility mapping (Sebinkarahisar,Turkey) 总被引:4,自引:1,他引:3
The case study presents GIS-aided statistically and physically based landslide susceptibility mapping in the landslide-prone
Avutmus district of Sebinkarahisar (Giresun, Turkey). Field investigations, analysis of geological data and laboratory tests
suggested that two important factors have acted together to cause sliding: ground water pressures and toe erosion. Frequency
ratio (FR) and stability index mapping (SINMAP) were used to create the landslide susceptibility maps based on a landslide
inventory; distance from drainage systems, faults and roads; slope angle and aspect; topographic elevation and topographical
wetness index; and vegetation cover. Validation of the models indicated high quality susceptibility maps with the more realistic
results were obtained from the statistically based FR model. 相似文献
76.
77.
研究浸出参数对电炉炼钢粉尘灰中选择浸出性Zn的影响,以Zn和Fe的浸出率为响应变量,以硫酸浓度、浸出温度、浸出时间和液固比为独立变量,采用基于三水平Box?Behnken的响应面法对浸出参数进行优化。对试验结果进行ANOVA分析和验证。在硫酸浓度为2.35 mol/L,浸出温度为25℃,浸出时间为56.42 min,液固比为5的条件下,可得到Zn的最大浸出率为79.09%, Fe的最小浸出率为4.08%。通过ANOVA分析表明,对Zn和Fe浸出率影响最大的因素为硫酸浓度和浸出温度。基于响应面法的模型与试验数据具有很好的一致性,Zn和Fe浸出率的相关系数分别为0.98和0.97。 相似文献
78.
Akturk O Tezcaner A Bilgili H Deveci MS Gecit MR Keskin D 《Journal of Bioscience and Bioengineering》2011,112(3):279-288
Sericin, a silk protein, has high potential for use in biomedical applications. In this study, wound dressing membranes of Sericin (S) and Collagen (C) were prepared by glutaraldehyde cross-linking at S/C; 2:1, 1:1, 1:2, and 0:1 weight ratios. They were stable in water for 4 weeks. However, increasing the proportion of sericin had decreasing effect on the membrane stability. Water swelling property of membranes was enhanced with sericin. The highest water swelling was obtained in 1:1 group (9.06 g/g), but increasing collagen or sericin content in the membranes had a diminishing effect. Highest water vapor transmission rate was obtained with 1:2 group (1013.80 g/m2/day). Oxygen permeability results showed that 1:2 (7.67 mg/L) and 2:1 (7.85 mg/L) S/C groups were better than the other groups. While sericin decreased the tensile strength and elongation of membranes, it increased modulus. Sericin also increased brittleness of membranes, but their UTS range (24.93–44.92 MPa) was still suitable for a wound dressing. Membranes were not penetrable to microorganisms. Cytotoxicity studies showed that fibroblasts and keratinocytes attached and gained their characteristic morphologies. They also proliferated on membranes significantly. After 1 week of subcutaneous implantation, a fibrous capsule formed around all membranes with an acute inflammation. Sericin containing membranes showed signs of degradation (at 2nd week), while collagen only membranes remained largely intact. Eventually, sericin containing membranes degraded in 3 weeks with moderate inflammatory response. Overall results suggest that sericin/collagen membranes would be favorable as wound dressing material when sericin ratio is less than or equal to the collagen component. 相似文献
79.
Şenol Durmuşoğlu İbrahim Uslu Tuncay Tunç Selda Keskin Arda Aytimur Ahmet Akdemir 《Journal of Polymer Research》2011,18(6):1999-2004
Boron doped poly(vinyl) alcohol/ bismuth - lanthanum acetate (PVA/Bi-La) nanofibers were prepared by electrospinning using
PVA as a precursor. The effect of boron doping was investigated in terms of solution properties, morphological changes and
thermal characteristics. The fibers were characterized by FT-IR, XRD, SEM and BET. The addition of boron did not only increase
the thermal stability of the fibers, but also their diameters, which yielded stronger fibers. XRD analyses showed that boron
doping increased the peak intensities and indicated that the boron doping enhanced the crystallite size. Moreover, no shifts
were noticed in diffraction angles for boron doped and undoped samples. Therefore, boron doping did not significantly alter
the lattice spacing. The SEM micrograph of the fibers showed that the addition of boron resulted in the formation of cross
linked bright surfaced fibers. Also, grain diameters of boron doped and undoped nanocrystalline sintered powders were measured
as 170 nm and 120 nm respectively. The BET results show that boron undoped and doped Bi2O3-La2O3 nanocrystalline powder ceramic structures sintered at 800 °C have surface areas of 20.44 m2/g and 12.93 m2/g, respectively. 相似文献
80.
Adnan Parlak Halit Yaar Can Haimoglu Ahmet Kolip 《Applied Thermal Engineering》2005,25(17-18):3042-3052
Higher NOx is one of the major problems to be overcomed in a low heat rejection (LHR) diesel engine as insulation leads to an increase in combustion temperature about 200–250 °C compared to an identical standard (STD) diesel engine. High combustion temperatures alter optimum injection timing of a LHR engine. With the proper adjustment of the injection timing, it is possible to partially offset the adverse effect of insulation on heat release rate and hence to obtain improved performance and lower NOx. However, the injection timing and brake specific fuel consumption (BSFC) trade-off must be considered together in performance and NOx emission point of view. In this study, optimum injection timing was found with 4 crank angle (34° CA) retarded before top dead centre (BTDC) in LHR diesel engine in comparison to that of STD diesel engine (38° CA BTDC). When the LHR engine was operated with the injection timing of the 38 crank angle, which is the optimum value of the STD engine, it was shown that NOx emission increased about 15%. However, when the injection timing was retarded to 34° CA in the LHR case, it was observed a decrease on the NOx emissions with about 40% and the brake specific fuel consumption (BSFC) with about 6% compared to that of the STD case. Thus, by retarding the injection timing, an additional 1.5% saving in fuel consumption was obtained. 相似文献