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1.
杜仲胶(EUG)主要由反式聚异戊二烯组成,是一种具有良好生物相容性、橡塑二重性和优异力学性能的天然高分子材料。近年来,EUG在新型生物基材料领域备受瞩目。EUG在室温下结晶度高,表现为刚性塑料状态,极大程度限制了其在功能材料领域的应用。因此,将EUG进行物理或化学改性,进而拓宽其应用范围已成为近年来的研究热点。本文详细介绍了EUG分子链结构特点,随后从物理改性和化学改性两个方面系统论述了EUG常见的改性方法及机理,如通过与其它材料共混或环氧化改性、硫化改性等改变EUG的硬度及弹性。对EUG在绿色轮胎与公路建设、形状记忆与自修复材料、减震与吸声材料、医用材料、生物降解复合材料等新型功能材料领域的最新研究进展进行了综述,并在此基础上展望了EUG在生物基高性能材料领域的发展前景。  相似文献   
2.
利用NaOH/尿素体系溶解纤维素并加入纳米碳酸钙,而后在盐酸溶液中再生,制得具备多孔结构的纤维素小球;之后采用丙烯酰胺对纤维素小球的羟基进行改性,接枝碳链并引入酰胺基,在碱性条件下酰胺基水解为羧基,得到改性纤维素基吸附剂;其可通过静电吸附和氢键间作用力固定漆酶。对接枝改性和漆酶固定化的最佳条件进行了探索,得到最佳改性条件为:时间6 h、温度50℃、单体配比8∶5、引发剂浓度0.08%;最佳固定化条件为:pH值=5.0、初始酶浓度10 g/L、固定化时间3 h。利用此最佳改性纤维素小球在最佳条件下固定的漆酶具有良好的热稳定性和可重复使用性,酶活提高了52%。结果表明,改性纤维素小球作为一种新型的绿色载体,在漆酶固定化方面具有广阔的应用前景。  相似文献   
3.
Hydrophilic biocompatible surfaces can be obtained by grafting stimuli-sensitive polymers onto commercially available medical devices. Thermo and pH-responsive polymers are two of the most studied materials due to their potential application as drug delivery systems. Poly(N-vinylcaprolactam) has a lower critical solution temperature (LCST) near to physiological temperature. However, when it is grafted with pH-sensitive moieties its LCST it is affected undergoing remarkable displacements. We studied the effect of acrylic acid (AAc), 4-vinylpyridine (4VP), and 1-vinylimidazole (Vim) on the LCST of N-vinylcaprolactam (NVCL) grafted onto silicone rubber (SR), and SR-g-NVCL (32.5 °C). The binary graft copolymers were obtained by ionizing grafting radiation using the simultaneous technique; the samples were characterized by Fourier transform infrared attenuated total reflectance (FTIR-ATR), cross-polarization magic angle spinning nuclear magnetic resonance (CP/MAS 13C-NMR), and thermogravimetrical analysis (TGA). LCST value was dramatically affected by the comonomer content; even it was observed the switching from LCST to upper critical solution temperature (UCST) for (SR-g-NVCL)-g-AAc and (SR-g-NVCL)-g-4VP samples. The observed behavior is rarely reported for binary graft copolymers. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48170.  相似文献   
4.
马来酸酐(MAH)与亚麻纤维(LF)C6-OH发生酯化反应制得了含有羧基的LF(LF-g-MAH),LF-g-MAH与羟基化多壁碳纳米管(MWCNTs-OH)的羟基发生酯化反应,得到了碳纳米管(CNTs)接枝的LF-g-MAH(记为LF-g-MAH-MWCNTs).用FTIR、XRD、SEM、EDX对LF-g-MAH-MWCNTs进行了表征,使用氧指数测定仪、微机电子万能试验机和四探针测试仪测试了其燃烧性能、力学性能、导电性和压力传感性.结果表明,CNTs的接枝对LF结晶性能、表面形态、燃烧性能、力学性能均没有明显影响,却使不导电的LF具有导电性和稳定灵敏的压力传感性能.手指按压即能使该传感器产生1.0~1.5 k?的电阻变化,体重分别为60和80 kg的测试者踩压能产生70和10 k?的电阻变化.  相似文献   
5.
The present in vivo study analyses both the inflammatory tissue reactions and the bone healing capacity of a newly developed bone substitute material (BSM) based on xenogeneic bone substitute granules combined with hyaluronate (HY) as a water-binding molecule. The results of the hyaluronate containing bone substitute material (BSM) were compared to a control xenogeneic BSM of the same chemical composition and a sham operation group up to 16 weeks post implantationem. A major focus of the study was to analyze the residual hyaluronate and its effects on the material-dependent healing behavior and the inflammatory tissue responses. The study included 63 male Wistar rats using the calvaria implantation model for 2, 8, and 16 weeks post implantationem. Established and Good Laboratory Practice (GLP)-conforming histological, histopathological, and histomorphometrical analysis methods were conducted. The results showed that the new hyaluronate containing BSM was gradually integrated within newly formed bone up to the end of the study that ended in a condition of complete bone defect healing. Thereby, no differences to the healing capacity of the control BSM were found. However, the bone formation in both groups was continuously significantly higher compared to the sham operation group. Additionally, no differences in the (inflammatory) tissue response that was analyzed via qualitative and (semi-) quantitative methods were found. Interestingly, no differences were found between the numbers of pro- and anti-inflammatory macrophages between the three study groups over the entire course of the study. No signs of the HY as a water-binding part of the BSM were histologically detectable at any of the study time points, altogether the results of the present study show that HY allows for an optimal material-associated bone tissue healing comparable to the control xenogeneic BSM. The added HY seems to be degraded within a very short time period of less than 2 weeks so that the remaining BSM granules allow for a gradual osteoconductive bone regeneration. Additionally, no differences between the inflammatory tissue reactions in both material groups and the sham operation group were found. Thus, the new hyaluronate containing xenogeneic BSM and also the control BSM have been shown to be fully biocompatible without any differences regarding bone regeneration.  相似文献   
6.
考察几种常用含羧基的乙烯基接枝单体对接枝改性羽毛蛋白浆料上浆性能的影响。在K2S2O8/NaHSO3氧化还原体系的引发下,将丙烯酸(AA)、甲基丙烯酸(MAA)及衣康酸(IA)单体分别接枝到天然羽毛蛋白的分子链上,制得接枝率相近而接枝支链分子结构不同的改性羽毛蛋白。然后采用3种接枝改性羽毛蛋白对纯棉经纱进行上浆实验,测试浆纱的增强率、减伸率、耐磨性和毛羽数量。结果表明,当选用AA作为接枝单体时,所得改性羽毛蛋白浆出的纱线性能较为优异。  相似文献   
7.
针对炭黑粒径小、表面能高、易团聚导致其分散性差的问题,选用表面接枝方法对炭黑进行了改性。考察了氧化剂种类、氧化时间与温度、接枝改性方法等条件对改性效果的影响。利用XRD、XPS、FTIR、TG等方法对接枝改性炭黑的过程进行了分析。考察了改性炭黑在水和甲苯中的分散稳定性。结果表明:浓硝酸的氧化效果比双氧水的好,含氧官能团以羧基和羟基为主。氧化不会对炭黑内部的微晶结构产生破坏。经表面异氰酸酯化后再接枝炭黑的热稳定性更好,在水中和甲苯中均表现出优异的分散稳定性。  相似文献   
8.
罗通通  孙玲 《中国塑料》2020,34(11):66-72
以聚乳酸(PLA)和聚己二酸/对苯二甲酸丁二酯(PBAT)为基体,杨木粉(WF)为填充增强材料,使用混炼机熔融共混制备PLA/PBAT/WF复合材料,采用熔融沉积成型(FDM)技术制备标准实验试样,通过扫描电子显微镜、红外光谱分析、旋转流变测试以及力学试验等方法,研究不同含量的硅烷偶联剂KH550对PLA/PBAT共混物以及PLA/PBAT/WF的相容性、流变性及力学性能的影响。结果表明,在偶联剂用量为3 %(质量分数,下同)时,拉伸强度提高了136 %;偶联剂KH550与 PLA和PBAT共价键偶联生成接枝聚合物,二者相容性得到提高;同时偶联剂与WF表面羟基发生缩聚反应有效的改善了其与PLA/PBAT的基体相容性,PLA/PBAT/WF复合材料的FDM的制件力学性能得到较大提升;复合材料的黏度随偶联剂含量的增加呈下降的趋势,含量为3 %时线材的综合打印性能及制品质量最佳。  相似文献   
9.
The hydrophilic modification of poly (vinylidene fluoride) (PVDF) membrane with poly (ethylene glycol) dimethacrylate (PEGDMA) through grafting reaction for antifouling was reported. The influence of PEGDMA content, reaction temperature and time, on the structure, morphology, antifouling, and hydrophilicity of PVDF-g-PEGDMA membrane has been investigated. The PEGDMA monomers that were grafted on the surface of PVDF microfiltration membrane were confirmed by Attenuation total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS), and morphology study conducted by SEM revealed the changes before and after modification. The protein adsorption, filtration performance, water content, and dynamic contact angle were used to characterize the antifouling and hydrophilicity of the modified PVDF membranes. Compared with the pristine PVDF membrane, the bovine serum albumin (BSA) adsorption on the PVDF-g-PEGDMA membrane decreased about 80%, and the water contact angle of the membrane dropped to 0°. Besides, the experimental results revealed no significant differences between the membrane samples with respect to pore size.  相似文献   
10.
研究了漆酶催化黄麻木质纤维接枝过渡单体丁子香酚,然后在漆酶/t-BHP催化下,在丁子香酚上进一步接枝丙烯酰胺的亲水化改性反应。结果表明,黄麻纤维接枝丁子香酚的XPS分峰图上观察到283.49 e V处存在CC的能谱峰,证明丁子香酚接枝到了黄麻纤维表面;溴量法测得在50℃、p H值=4、丁子香酚浓度5 mmol/L、漆酶用量1.68 U/m L条件下反应4 h接枝过渡单体效果最好,接枝率为1.06%。在黄麻纤维桥接丁子香酚接枝丙烯酰胺的红外光谱图上呈现酰胺基团的红外特征吸收峰,说明黄麻纤维表面成功接枝丙烯酰胺;微量凯氏定氮法测得黄麻纤维桥接丁子香酚接枝丙烯酰胺的接枝率为3.66%。  相似文献   
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