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71.
Jianchun Xu Zhao Li Xuchao Pan Xi Wen Jinqing Cao Wen Gong Shaolong Yang Ming Lei Fangzhou Yao Ke Bi 《Advanced functional materials》2023,33(8):2210868
Mechanical antennas based on piezoelectric materials can effectively reduce the size of long wave antennas down to 1/1000 of the wavelength (from km scale to mm level). However, the narrow bandwidth and weak field intensity seriously restrict its practical applications in transmission distance and channel capacity. Here, a mechanical antenna-based electrostrictive effect of relaxor ferroelectric ceramic (PMN-PT) is proposed to improve radiation capacity and achieve ultra-wideband characteristics (10 kHz–1 MHz). Due to the ultra-high dielectric constant at working temperature and the relationship between the strain and applied field intensity, the proposed antenna gets rid of the dependence on the poled materials and exhibits excellent communication properties beyond traditional mechanical antennas, which are experimentally demonstrated by a practical wireless communication system. Only using a single proposed mechanical antenna with 8 mm diameter and 3 mm thickness, the effective communication with a transmission distance of 200 m can be realized. This design offers a promising way of constructing mechanical antennas for long-wave communication. 相似文献
72.
Zi Li Huifeng Yao Lijiao Ma Jingwen Wang Zhaozhao Bi Shijie Wang Susanne Seibt Tao Zhang Ye Xu Junzhen Ren Yang Xiao Cunbin An Wei Ma Jianhui Hou 《Advanced functional materials》2023,33(26):2300202
Organic solar cells (OSCs) have achieved much progress with rapidly increasing power conversion efficiencies (PCEs). It should be noted that the top-performance OSCs are generally consisted of active materials with complex chemical structures, resulting in high costs. Here, combining the material design and morphology control, high-efficiency OSCs are fabricated by a low-cost donor: acceptor blend. A completely non-fused electron acceptor named Tz is designed and synthesized via introducing thiazole units on both sides of a bithiophene core, which shows an outstanding PCE of 13.3% with a typical polythiophene donor. More importantly, optimization guidelines are presented to get excellent morphology for low-cost donor:acceptor systems. Three polythiophenes are selected, poly(3-hexylthiophene) and its two derivatives with electron-withdrawing substitutions (PDCBT and PDCBT-2F), as donors to fabricate the cell devices. The computational and experimental data reveal that decreasing the electrostatic interaction between polythiophene and Tz is the key to getting a suppressed miscibility and thus a high phase purity. This study provides insight into the molecular design and donor:acceptor matching requirements for high-efficiency and low-cost OSCs. 相似文献
73.
Jiafeng Zhu Qingyuan Bi Yinghao Tao Wenyao Guo Jinchen Fan Yulin Min Guisheng Li 《Advanced functional materials》2023,33(15):2213131
Designing and developing visible-light-responsive materials for solar to chemical energy is an efficient and promising approach to green and sustainable carbon-neutral energy systems. Herein, a facile in situ growth hydrothermal strategy using Mo-modified ZnIn2S4 (Mo-ZIS) nanosheets coupled with NiTiO3 (NTO) microrods to synthesize multifunctional Mo-modified ZIS wrapped NTO microrods (Mo-ZIS@NTO) photocatalyst with enhanced interfacial electric field (IEF) effect and typical S-scheme heterojunction is reported. Mo-ZIS@NTO catalyst possesses wide-spectrum light absorption properties, excellent visible light-to-thermal energy effect, electron mobility, charges transfer, and strong IEF and exhibits excellent solar-to-chemical energy conversion for efficient visible-light-driven photocatalytic hydrogen evolution. Notably, the engineered Mo1.4-ZIS@NTO catalyst exhibits superior performance with H2 evolution rate of up to 14.06 mmol g−1 h− 1 and the apparent quantum efficiency of 44.1% at 420 nm. The scientific explorations provide an in-depth understanding of microstructure, S-scheme heterojunction, enhanced IEF, Mo-dopant facilitation effect. Moreover, the theoretical simulations verify the critical role of Mo element in promoting the adsorption and activation of H2O molecules, modulating the H adsorption behavior on active S sites, and thus accelerating the overall catalytic efficiency. The photocatalytic hydrogen evolution mechanism via S-scheme heterojunction with adjustable IEF regulation over Mo1.4-ZIS@NTO is also demonstrated. 相似文献
74.
75.
相转移催化氧化合成苯甲酸 总被引:1,自引:0,他引:1
苯甲酸一般由甲苯氧化而成 ,工业上采用液相空气氧化生产苯甲酸[1 ] 。KMnO4氧化甲苯制备苯甲酸的方法是在实验室中最常见的一种方法[2 ] ,该法的优点是反应条件温和 ,操作简便 ;其缺点是反应时间长 ,产率低 (低于 40 % ) [3] 。为了提高KMnO4氧化法的产率 ,本文采用十六烷基三丁基溴化磷 (HDTBP)和苄基三乙基氯化铵(BTEA)作相转移催化剂氧化甲苯制备苯甲酸 ,具有时间短 ,收率高等优点。同时又考虑到HDTBP的催化效果虽然好 ,但价格昂贵 ,因此本文采用价廉易得的苄基三乙基氯化铵 (BTEA)作相转移催化剂氧化甲苯制… 相似文献
76.
Eu(Ⅲ)、Tb(Ⅲ)、Ho(Ⅲ)、Tm(Ⅲ)和Lu(Ⅲ)与N,N′-二(邻羟基亚甲基)乙二胺配合物的研究 总被引:1,自引:0,他引:1
Dutt曾合成稀土离子与N,N′-二(邻羟基亚甲基)乙二胺的稀土双希夫碱配合物。但未见报道Eu(Ⅲ),Tb(Ⅲ),Ho(Ⅲ),Tm(Ⅲ),Lu(Ⅲ)与双希夫碱N,N′-二(邻羟基亚甲基)乙二胺的配合物。本工作合成了这5种双希夫碱配合物。 所用稀土氧化物纯度大于99.9%(上海跃龙化工厂)。水杨醛(CP,用前经减压蒸馏提纯)。稀土硝酸盐Ln(NO_3)_3·xH_2_由稀土氧化物与硝酸反应制得。其余试剂均为分析纯。 仪器为Perkin-Elmer 240-C元素分析仪;Nicolet-5DX型红外光谱仪,KBr压片;岛津UV- 相似文献
77.
汞电极表面电荷的快速估算 总被引:1,自引:0,他引:1
本文报导了用交流示波极谱快速估算电极表面电荷的方法。该方法使用仪器简单,测量快速,操作简便,在吸附研究中很有用处。 相似文献
78.
J. V. Crivello Daoshen Bi 《Journal of polymer science. Part A, Polymer chemistry》1993,31(12):3109-3119
Silicon-containing epoxide compounds bearing Si ? H groups can be readily prepared in high yields by the regioselective rhodium-catalyzed monohydrosilation of α,ω-dihydrogen functional siloxanes and silanes with vinyl epoxides. The remaining Si ? H groups in these compounds can be further selectively hydrosilated with unsaturated epoxides to give a series of unique ambifunctional monomers containing two different epoxide groups in the same molecule. The photopolymerization of these monomers has been studied using analytical techniques including real time infrared spectroscopy and differential scanning photocalorimetry. On photopolymerization, the new monomers yield interesting networks. © 1993 John Wiley & Sons, Inc. 相似文献
79.
Paul De Bièvre 《Accreditation and quality assurance》2000,5(10-11):423-428
Talking about "traceability" means talking about a "property of the result of a measurement", about "the value of a standard", about "stated references" and about an "unbroken chain of comparisons". It describes by which comparison, and to which other value, the result of a measurement has been obtained, i.e. is "traceable to". It is about the underlying structure of the measurement process of the result of a measurement and therefore about the authority of the result. Since values carried by (certified) reference materials have also been obtained by measurement, the definition of traceability equally applies. Traceability in the context of reference materials is also about the authority of the values carried by the (certified) reference materials and is, therefore, of key importance for the authority of the reference materials themselves. Hence, values of results of measurements constitute part of the traceability chain and their uncertainties are an intrinsic accompanying phenomenon. Uncertainties need a traceability chain against which they can be evaluated, and a traceability chain is an a priori requirement for evaluating the uncertainty budget of a measurement result. An attempt has been made to exemplify "traceability" chains in some types of chemical measurement and to identify the degree of international agreement on the key elements of "traceability". It is concluded that there is less than universal agreement on this issue. The debate should continue in order to arrive at the international understanding and agreement needed, as "traceability" is now being incorporated in the International Organization for Standardization (ISO), the International Laboratory Accreditation Co-operation (ILAC) and in other "guiding" or regulatory documents. It is also the reason why the Institute for Reference Materials and Measurements (IRMM) has taken up the study of the concept in its core programme on Metrology in Chemistry, and why it sponsored the Workshop in Bratislava. 相似文献
80.
一阶导数光谱K系数法同时测定硝基酚钠三组分 总被引:2,自引:0,他引:2
研究和建立了同时测定硝基酚钠混合三组份的新方法——一阶导数光谱K系数法。确定了最佳实验条件和测定波长,方法简便、快速、准确。通过对动植物细胞赋活增进剂中邻硝基酚钠、对硝基酚钠、5-硝基愈创木酚钠三组份的直接测定,其相对误差小于2%,相对标准偏差小于3%,回收率为99~103%。 相似文献