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481.
十二烯基琥珀酸淀粉酯的制备及其性质研究 总被引:2,自引:0,他引:2
研究了反应温度、反应时间、体系pH、十二烯基琥珀酸酐用量等条件对酯化反应的影响。采用红外光谱对产品进行了结构表征,结果表明反应后淀粉分子上的确引入了烯基琥珀酸酐基团;用扫描电镜观察产品的颗粒形态,发现十二烯基琥珀酸淀粉酯(SSDS)颗粒表面受到一定程度的破坏。研究了SSDS的性质,结果表明SSDS乳化能力强,而且乳化稳定性比较好,SSDS糊符合假塑性流体特征。 相似文献
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We attempted to introduce crosslinking into poly(butylene adipate‐co‐succinate) (PBAS) to improve the properties, such as the mechanical strength and elasticity, by a simple addition of dicumyl peroxide (DCP). Prior to curing, the thermal stability of PBAS was investigated. Above 170°C PBAS was severely degraded, and the degradation could not be successfully stabilized by an antioxidant. The PBAS was effectively crosslinked by DCP, and the gel fraction increased as the DCP content increased. A major structure of the crosslinked PBAS was an ester and aliphatic group. The tensile strength and elongation of PBAS were improved with an increasing content of DCP, but there was little affect on the tear strength. The biodegradability of crosslinked PBAS was not seriously deteriorated. A higher degree of crosslinking gave a lower heat of crystallization and heat of fusion. However, the melt crystallization temperatures of the crosslinked PBAS were higher than that of PBAS. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 637–645, 2001 相似文献
484.
Crystallization behaviour of biodegradable poly(ethylene succinate) from the amorphous state 总被引:1,自引:0,他引:1
Nonisothermal and isothermal crystallization kinetics of biodegradable poly(ethylene succinate) (PES) from the amorphous state were studied by differential scanning calorimetry (DSC). For the nonisothermal crystallization, there were two crystallization exotherms upon heating from the amorphous state. One major crystallization exotherm located at low temperature corresponded to the real cold crystallization of PES, while the other minor one located at high temperature may correspond to the melt-recrystallization of the unstable crystals formed during the nonisothermal crystallization earlier. Several methods, such as Avrami equation, Tobin equation and Ozawa equation, were applied to describe the nonisothermal crystallization process of PES. Meanwhile, Avrami equation was also employed to study the isothermal crystallization of PES from the amorphous state. Similar to the nonisothermal crystallization the minor crystallization exotherm was also found in the DSC trace upon heating to the melt after the isothermal cold crystallization finished completely, and was attributed to the melt-recrystallization of the unstable crystals formed during the isothermal cold crystallization. Temperature modulated differential scanning calorimetry (TMDSC) was used in this work to investigate the origin of the minor crystallization exotherm located at high temperature, and the TMDSC experiments gave a direct evidence that the origin of the minor crystallization exotherm was from the melt-recrystallization of the originally existed unstable crystals formed through previous crystallization. 相似文献
485.
纳米二氧化硅对PBS结晶性能及力学性能的影响 总被引:1,自引:0,他引:1
采用热重分析法研究了硅烷偶联剂用量对纳米二氧化硅(SiO2)的表面改性效果;通过差示扫描量热(DSC)、热台偏光显微镜(POM)及力学性能等测试手段研究了改性纳米SiO2对聚丁二酸丁二醇酯(PBS)结晶性能和力学性能的影响。结果表明,在偶联剂用量为5份、渗透剂用量为2份的条件下,纳米SiO2的表面改性效果最好。纳米SiO2有异相成核作用,可以使PBS的结晶速率增大,相对结晶度降低,但对结晶温度的影响不大,仅在高填充量时(10 %)有4 ℃的增幅。随着纳米SiO2含量的增加,PBS的拉伸强度和断裂伸长率先升高后降低,但拉伸强度的变化幅度很小,断裂伸长率则在纳米SiO2含量为1.5 %时达到最大值10.79 %,较纯PBS的7.53 %提高了43.3 %。 相似文献
486.
探讨了以马来酸为原料两条路线合成丁二酸二甲酯的效果,结果表明,马来酸先酯化后加氢的技术路线具有选择性高、速率快的明显优势。考察了水和甲醇作溶剂,对马来酸酯化产物加氢反应选择性的影响。结果表明,在反应温度50~70℃、压力0.4~1.2 MPa的低温低压的温和条件下,马来酸二甲酯转化率、丁二酸二甲酯的选择性和收率分别为100%,100%和99.5%以上;氢氧化钌催化剂具有良好的催化性能,催化剂使用5釜后,反应时间开始延长,但不影响丁二酸二甲酯的选择性。 相似文献
487.
将天然植物虎杖粉碎,分别与可生物降解材料PBS直接共混和提取后共混,制备了PBS/虎杖复合材料。研究了PBS/虎杖粉末及PBS/虎杖提取物复合材料的结晶性能、亲疏水性、热稳定性、力学性能及抗菌性能。结果表明,虎杖粉末和提取物的添加均对PBS的晶型没有影响,且能起到成核剂的作用,两者成分中均以亲水性成分为主。PBS/虎杖粉末复合材料的热性能、力学性能均优于PBS/虎杖提取物复合材料。两种天然虎杖添加物赋予了复合材料抗菌功能性,PBS/虎杖提取物复合材料抗菌效果相对较好。各种比例复合材料可根据其综合性能应用于不同场合。 相似文献
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490.
Guoming Liu Konrad Schneider Liuchun Zheng Xiuqin Zhang Chuncheng Li Manfred Stamm Dujin Wang 《Polymer》2014
The structure evolution of poly(vinylidene fluoride)/poly(butylene succinate) (PVDF/PBS) blends during stretching above the melting point of PBS is investigated by synchrotron-based simultaneous wide angle and small angle X-ray scattering (WAXS/SAXS). Before stretching, PVDF crystallizes into the α-form, whereas the chains of molten PBS locate at the inter-lamellar amorphous phase of PVDF. Crystal transition from α to β of PVDF is observed in all samples during stretching. The morphological transformation from a lamellar structure into a fibrillar structure occurs at low and intermediate strains. With further deformation, a “stretching induced phase separation” phenomenon is observed. The final microstructure of PVDF/PBS blends contains PVDF microfibrils with PBS chains preferentially distributed in the inter-fibrillar region. The PBS molecular weight influences the onset and end strain for the transition. A new “two-step model” is proposed to describe the deformation process. 相似文献