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排序方式: 共有143条查询结果,搜索用时 187 毫秒
1.
Sensitive Detection of Carcinoembryonic Antigen Using Stability‐Limited Few‐Layer Black Phosphorus as an Electron Donor and a Reservoir 下载免费PDF全文
Jian Peng Youqun Lai Yuanyuan Chen Jun Xu Liping Sun Jian Weng 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(15)
The instability of few‐layer black phosphorus (FL‐BP) hampers its further applications. Here, it can be demonstrated that the instability of FL‐BP can also be the advantage for application in biosensor. First, gold nanoparticle/FL‐BP (BP‐Au) hybrid is facilely synthesized by mixing Au precursor with FL‐BP. BP‐Au shows outstanding catalytic activity (K = 1120 s?1 g?1) and low activation energy (17.53 kJ mol?1) for reducing 4‐nitrophenol, which is attributed to the electron‐reservoir and electron‐donor properties of FL‐BP, and synergistic interaction of Au nanoparticles and FL‐BP. Oxidation of FL‐BP after catalytic reaction is further confirmed by transmission electron microscope, X‐ray photoelectron spectroscopy, and zeta potentials. Second, the catalytic activity of BP‐Au can be reversibly switched from “inactive” to “active” upon treatment with antibody and antigen in solution, thus providing a versatile platform for label‐free colorimetric detection of biomarkers. The sensor shows a wide detection range (1 pg mL?1 to –10 µg mL?1), high sensitivity (0.20 pg mL?1), and selectivity for detecting carcinoembryonic antigen (CEA). Finally, the biosensor has been used to detect CEA in colon and breast cancer clinical samples with satisfactory results. Therefore, the instability of BP can also be the advantage for application in detecting cancer biomarker in clinic. 相似文献
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《分离科学与技术》2012,47(6):824-831
This paper deals with studies on the extraction of uranium(VI) from phosphoric acid medium using (2-ethylhexyl)phosphonic acid mono 2-ethylhexyl ester and tri-n-octylphosphine oxide individually as well as from their synergistic mixture. Different extraction parameters were investigated. With an increase in phosphoric acid concentration in the aqueous phase, the distribution ratio (Du) was found to decrease in all the cases. Synergism was observed when a mixture of PC-88A and TOPO was used. The synergistic mixture in the mole ratio of 4:1 (1.80 M PC-88A: 0.45 M TOPO) in xylene was found to be most suitable for uranium extraction. Among the various strip liquors used, 5% (w/v) solution of (NH4)2CO3 was found to be the most suitable. Using a mixture of 1.8 M PC-88A and 0.45 M TOPO as the extractant system and 0.5 M ammonium carbonate as the stripping agent, uranium recovery was found to be better than 97% ± 3% in multiple contacts, (n = 2) from actual Davies Gray Waste while in case of wet phosphoric acid more than 52% ± 3% (n = 3) only could be recovered where n is the number of contacts. 相似文献
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Understanding the Charge‐Transfer State and Singlet Exciton Emission from Solution‐Processed Small‐Molecule Organic Solar Cells 下载免费PDF全文
6.
N. Y. Garces Lijun Wang N. C. Giles L. E. Halliburton D. C. Look D. C. Reynolds 《Journal of Electronic Materials》2003,32(7):766-771
Electron paramagnetic resonance (EPR) has been used to monitor the diffusion of lithium ions into single crystals of ZnO.
The in-diffusion occurs when a crystal is embedded in LiF powder and then held in air at temperatures near 750°C for periods
of time ranging up to 22 h. These added lithium ions occupy zinc sites and become singly ionized acceptors (because the material
is initially n type). A corresponding reduction in the number of neutral shallow donors is observed with EPR. To monitor the
lithium acceptors, we temporarily convert them to the EPR-active neutral acceptor state by exposure to laser light (325 nm
or 442 nm) at low temperatures. Also, after each diffusion treatment, we monitor the EPR signal of singly ionized copper acceptors
and the photo-induced EPR signal of neutral nitrogen acceptors. These nitrogen and copper impurities are initially present
in the crystal, at trace levels, and are made observable by the thermal anneals. Infrared-absorption measurements at room
temperature in the 2–10 μm region show that the concentration of free carriers decreases as lithium is added to the crystal.
After 22 h at 750°C in the LiF powder, the free-carrier absorption is no longer present, and the crystal is semi-insulating. 相似文献
7.
Shaoqing Zhang Yunpeng Qin Jie Zhu Jianhui Hou 《Advanced materials (Deerfield Beach, Fla.)》2018,30(20)
Fluorine‐contained polymers, which have been widely used in highly efficient polymer solar cells (PSCs), are rather costly due to their complicated synthesis and low yields in the preparation of components. Here, the feasibility of replacing the critical fluorine substituents in high‐performance photovoltaic polymer donors with chlorine is demonstrated, and two polymeric donors, PBDB‐T‐2F and PBDB‐T‐2Cl, are synthesized and compared in parallel. The synthesis of PBDB‐T‐2Cl is much simpler than that of PBDB‐T‐2F. The two polymers have very similar optoelectronic and morphological properties, except the chlorinated polymer possess lower molecular energy levels than the fluorinated one. As a result, the PBDB‐T‐2Cl‐based PSCs exhibit higher open circuit voltage (Voc) than the PBDB‐T‐2F‐based devices, leading to an outstanding power conversion efficiency of over 14%. This work establishes a more economical design paradigm of replacing fluorine with chlorine for preparing highly efficient polymer donors. 相似文献
8.
High‐Performance Nonfullerene Polymer Solar Cells based on Imide‐Functionalized Wide‐Bandgap Polymers 下载免费PDF全文
Baobing Fan Kai Zhang Xiao‐Fang Jiang Lei Ying Fei Huang Yong Cao 《Advanced materials (Deerfield Beach, Fla.)》2017,29(21)
High‐performance nonfullerene polymer solar cells (PSCs) are developed by integrating the nonfullerene electron‐accepting material 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophne) (ITIC) with a wide‐bandgap electron‐donating polymer PTzBI or PTzBI‐DT, which consists of an imide functionalized benzotriazole (TzBI) building block. Detailed investigations reveal that the extension of conjugation can affect the optical and electronic properties, molecular aggregation properties, charge separation in the bulk‐heterojunction films, and thus the overall photovoltaic performances. Single‐junction PSCs based on PTzBI:ITIC and PTzBI‐DT:ITIC exhibit remarkable power conversion efficiencies (PCEs) of 10.24% and 9.43%, respectively. To our knowledge, these PCEs are the highest efficiency values obtained based on electron‐donating conjugated polymers consisting of imide‐functionalized electron‐withdrawing building blocks. Of particular interest is that the resulting device based on PTzBI exhibits remarkable PCE of 7% with the thickness of active layer of 300 nm, which is among the highest values of nonfullerene PSCs utilizing thick photoactive layer. Additionally, the device based on PTzBI:ITIC exhibits prominent stability, for which the PCE remains as 9.34% after thermal annealing at 130 °C for 120 min. These findings demonstrate the great promise of using this series of wide‐bandgap conjugated polymers as electron‐donating materials for high‐performance nonfullerene solar cells toward high‐throughput roll‐to‐roll processing technology. 相似文献
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分别以四乙氧基硅烷(TEOS)、二环戊基二甲氧基硅烷(DCPDMS)及复配的TEOS/DCPDMS为外给电子体,考察了BCZ催化剂的聚合性能及所得聚丙烯的熔体流动速率(MFR)和等规度。实验结果表明,TEOS为外给电子体时BCZ催化剂的氢调敏感性较好,而DCPDMS为外给电子体所得聚丙烯的等规性能较好;通过调节BCZ催化剂中TEOS/DCPDMS的配比,可在一定范围内调节聚丙烯的等规度和MFR,当n(TEOS)∶n(DCPDMS)=90∶10时,可制得MFR(10min)为49.1 g、等规度为95.6%的聚丙烯;采用TEOS/DCPDMS复配外给电子体时,BCZ催化剂可在较高的聚合温度下制备MFR和等规度均较高的聚丙烯产品。 相似文献