全文获取类型
收费全文 | 644篇 |
免费 | 72篇 |
国内免费 | 46篇 |
专业分类
化学 | 540篇 |
晶体学 | 6篇 |
力学 | 52篇 |
综合类 | 12篇 |
数学 | 33篇 |
物理学 | 119篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 17篇 |
2021年 | 23篇 |
2020年 | 44篇 |
2019年 | 30篇 |
2018年 | 25篇 |
2017年 | 23篇 |
2016年 | 38篇 |
2015年 | 37篇 |
2014年 | 39篇 |
2013年 | 33篇 |
2012年 | 50篇 |
2011年 | 61篇 |
2010年 | 33篇 |
2009年 | 51篇 |
2008年 | 27篇 |
2007年 | 37篇 |
2006年 | 43篇 |
2005年 | 25篇 |
2004年 | 12篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1999年 | 12篇 |
1998年 | 15篇 |
1997年 | 11篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1986年 | 1篇 |
1959年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有762条查询结果,搜索用时 640 毫秒
71.
Poly-N-acetylaniline (PNAANI) film, an analogous polymer of polyaniline, was electrodeposited on a glassy carbon (GC) electrode by an electro-dynamic scan method. Cyclic voltammetry was used to characterize the electrochemical response. The cyclic voltammograms of PNAANI films after its electro-hydrolysis and electro-chlorination were interpreted. The electrode processes are discussed and the electrochemical degradation mechanism of PNAANI film proposed based on the experimental results. 相似文献
72.
Individual Surface‐Engineered Microorganisms as Robust Pickering Interfacial Biocatalysts for Resistance‐Minimized Phase‐Transfer Bioconversion 下载免费PDF全文
Zhaowei Chen Haiwei Ji Chuanqi Zhao Enguo Ju Prof. Dr. Jinsong Ren Prof. Dr. Xiaogang Qu 《Angewandte Chemie (International ed. in English)》2015,54(16):4904-4908
A powerful strategy for long‐term and diffusional‐resistance‐minimized whole‐cell biocatalysis in biphasic systems is reported where individually encapsulated bacteria are employed as robust and recyclable Pickering interfacial biocatalysts. By individually immobilizing bacterial cells and optimizing the hydrophobic/hydrophilic balance of the encapsulating magnetic mineral shells, the encased bacteria became interfacially active and locate at the Pickering emulsion interfaces, leading to dramatically enhanced bioconversion performances by minimizing internal and external diffusional resistances. Moreover, in situ product separation and biocatalyst recovery was readily achieved using a remote magnetic field. Importantly, the mineral shell effectively protected the entire cell from long‐term organic‐solvent stress, as shown by the reusability of the biocatalysts for up to 30 cycles, while retaining high stereoselective catalytic activities, cell viabilities, and proliferative abilities. 相似文献
73.
Zhijun Zhang Yijia Guan Meng Li Andong Zhao Jinsong Ren Xiaogang Qu 《Chemical science》2015,6(5):2822-2826
Sandwich ELISA methods have been widely used for biomarker and pathogen detection because of their high specificity and sensitivity. However, the main drawbacks of this assay are the cost, the time-consuming procedure for the isolation of antibodies and their poor stability. To overcome these restrictions, we herein fabricated artificial antibodies based on imprinting technology and developed a sandwich ELISA for pathogen detection. Both the capture and detection antibodies were obtained via an in situ method, with simplicity, rapidity and low cost. The peroxidase mimics, the CeO2 nanoparticles, as signal generators were integrated with the detection antibody. The fabricated artificial antibodies exhibited not only natural antibody-like binding affinities and selectivities, but also superior stability and reusability. The detection limit was about 500 CFU mL–1, which is much lower than that of traditional ELISA methods (104 to 105 CFU mL–1). Furthermore, the capture antibody can disinfect pathogens in situ. 相似文献
74.
Yang Renchun Zhang Zhihua Wu Junsheng Li Xiaogang Wang Luhai 《Kinetics and Catalysis》2015,56(2):222-225
Kinetics and Catalysis - To enhance the surface active sites of the catalyst, a series of La-modified Ni/γ-Al2O3 samples were prepared by hydrothermal impregnation method and characterized by... 相似文献
75.
Based on enzymatic reactions-triggered changes of pH values and biocomputing, a novel and multistage interconnection biological network with multiple easy-detectable signal outputs has been developed. Compared with traditional chemical computing, the enzyme-based biological system could overcome the interference between reactions or the incompatibility of individual computing gates and offer a unique opportunity to assemble multicomponent/multifunctional logic circuitries. Our system included four enzyme inputs: β-galactosidase (β-gal), glucose oxidase (GOx), esterase (Est) and urease (Ur). With the assistance of two signal transducers (gold nanoparticles and acid–base indicators) or pH meter, the outputs of the biological network could be conveniently read by the naked eyes. In contrast to current methods, the approach present here could realize cost-effective, label-free and colorimetric logic operations without complicated instrument. By designing a series of Boolean logic operations, we could logically make judgment of the compositions of the samples on the basis of visual output signals. Our work offered a promising paradigm for future biological computing technology and might be highly useful in future intelligent diagnostics, prodrug activation, smart drug delivery, process control, and electronic applications. 相似文献
76.
77.
Carbon nanodots (C-Dots) have attracted much attention in recent years due to their low cost, ready scalability, excellent chemical stability, biocompatibility and multicolor luminescence. Here, we report a facile strategy for producing highly luminescent, surface-different nitrogen-doped carbon dots (C-Dots) by using different ionic liquids (ILs). Intriguingly, the surface-different C-Dots show different selectivity for Cu2+ and Fe3+. To the best of our knowledge, this is the first example which shows that ILs are excellent precursors for producing luminescent nanomaterial used for detection of different metal ions. The resultant nitrogen-doped C-Dots are highly photoluminescent and can be used for multicolor bioimaging. Most notable, by taking different ILs as precursors, we obtain surface-different C-Dots, which can be directly used for selective detection of Cu2+ and Fe3+ without any modification. These C-Dots based sensors exhibit high sensitivity and selectivity and the sensing process can be easily accomplished with one-step rapid operation. More importantly, compared with other method using QDs, organic dyes and organic solvent, this strategy is much more eco-friendly. This work may offer a new approach for developing low cost and sensitive C-Dots-based sensors for biological and environmental applications. 相似文献
78.
79.
Wang C Pu F Lin Y Ren J Dohn C Nakatani K Qu X 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(29):8189-8194
A robust and photoresponsive DNA network has been designed and constructed from branched DNA and molecular glue. The molecular glue is photoswitchable and can specifically bind to G-G mismatched double-stranded DNA. The assembly process can be reversibly controlled by manipulating the wavelength of light. The approach is flexible, allowing tuning of the size, morphology as well as the cavity of the network by variation of the molar ratio and the isotropic/anisotropic character of the branched building blocks. The assembled architectures are versatile and heat tolerant. These properties should allow the use of the network in further applications. 相似文献
80.
Novel liquid-liquid-solid microextraction method with molecularly imprinted polymer-coated stainless steel fiber for aqueous sample pretreatment 总被引:1,自引:0,他引:1
A novel liquid-liquid-solid microextraction (LLSME) method was developed to overcome the well-known water-compatibility problem of molecularly imprinted polymers (MIPs). The enrichment factors with MIP-LLSME method were within 70-210 for trace chloroacetanilide herbicides under optimized extraction conditions. The method was characterized by simplicity, low solvent-consumption and high selectivity, and it was suitable for the one-step pretreatment of various aqueous samples such as river water and farm water. 相似文献