全文获取类型
收费全文 | 444篇 |
免费 | 31篇 |
国内免费 | 5篇 |
专业分类
化学 | 268篇 |
力学 | 13篇 |
数学 | 93篇 |
物理学 | 106篇 |
出版年
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 19篇 |
2018年 | 20篇 |
2017年 | 23篇 |
2016年 | 20篇 |
2015年 | 17篇 |
2014年 | 21篇 |
2013年 | 30篇 |
2012年 | 44篇 |
2011年 | 38篇 |
2010年 | 23篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 20篇 |
2006年 | 11篇 |
2005年 | 16篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 4篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有480条查询结果,搜索用时 187 毫秒
471.
Dr. Vinh X. Truong Dr. Katharina Ehrmann Maximilian Seifermann Prof. Dr. Pavel A. Levkin Prof. Dr. Christopher Barner-Kowollik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(25):e202104466
The ability of light to remotely control the properties of soft matter materials in a dynamic fashion has fascinated material scientists and photochemists for decades. However, only recently has our ability to map photochemical reactivity in a finely wavelength resolved fashion allowed for different colors of light to independently control the material properties of polymer networks with high precision, driven by monochromatic irradiation enabling orthogonal reaction control. The current concept article highlights the progress in visible light-induced photochemistry and explores how it has enabled the design of polymer networks with dynamically adjustable properties. We will explore current applications ranging from dynamic hydrogel design to the light-driven adaptation of 3D printed structures on the macro- and micro-scale. While the alternation of mechanical properties via remote control is largely reality for soft matter materials, we herein propose the next frontiers for adaptive properties, including remote switching between conductive and non-conductive properties, hydrophobic and hydrophilic surfaces, fluorescent or non-fluorescent, and cell adhesive vs. cell repellent properties. 相似文献
472.
Chemistry of Natural Compounds - 相似文献
473.
Dr. William Ndugire Dang Truong N. G. Hasitha Raviranga Jingzhe Lao Prof. Dr. Olof Ramström Prof. Dr. Mingdi Yan 《Angewandte Chemie (International ed. in English)》2023,62(11):e202214086
In this work, we show that the addition of thiourea (TU) initiated broad-spectrum antimicrobial activity of otherwise inactive D-maltose-capped gold nanoclusters (AuNC-Mal). For example, AuNC-Mal/TU was effective against multidrug-resistant Pseudomonas aeruginosa with a minimum inhibitory concentration (MIC) of 1 μg mL−1 (2.5 μM [Au]) while having 30–60 times lower in vitro cytotoxicity against mammalian cells. The reaction of AuNC-Mal and TU generated the antimicrobial species of [Au(TU)2]+ and smaller AuNCs. TU increased the accumulation of Au in bacteria and helped maintain the oxidation state as AuI (vs. AuIII). The modes of action included the inhibition of thioredoxin reductase, interference with the CuI regulation and depletion of ATP. Moreover, the antimicrobial activity did not change in the presence of colistin or carbonyl cyanide 3-chlorophenylhydrazone, suggesting that AuNC-Mal/TU was indifferent to the outer membrane barrier and to bacterial efflux pumps. 相似文献
474.
Thy Truong Kei G. I. Webber S. Madisyn Johnston Hannah Boekweg Caleb M. Lindgren Yiran Liang Alissia Nydegger Xiaofeng Xie Tsz-Ming Tsang D. A. Dasun N. Jayatunge Joshua L. Andersen Samuel H. Payne Ryan T. Kelly 《Angewandte Chemie (International ed. in English)》2023,62(34):e202303415
We combined efficient sample preparation and ultra-low-flow liquid chromatography with a newly developed data acquisition and analysis scheme termed wide window acquisition (WWA) to quantify >3,000 proteins from single cells in rapid label-free analyses. WWA employs large isolation windows to intentionally co-isolate and co-fragment adjacent precursors along with the selected precursor. Optimized WWA increased the number of MS2-identified proteins by ≈40 % relative to standard data-dependent acquisition. For a 40-min LC gradient operated at ≈15 nL/min, we identified an average of 3,524 proteins per single-cell-sized aliquot of protein digest. Reducing the active gradient to 20 min resulted in a modest 10 % decrease in proteome coverage. Using this platform, we compared protein expression between single HeLa cells having an essential autophagy gene, atg9a, knocked out, with their isogenic WT parental line. Similar proteome coverage was observed, and 268 proteins were significantly up- or downregulated. Protein upregulation primarily related to innate immunity, vesicle trafficking and protein degradation. 相似文献
475.
Dr. Richard Whitfield Dr. Glen R. Jones Dr. Nghia. P. Truong Dr. Lewis E. Manring Prof. Athina Anastasaki 《Angewandte Chemie (International ed. in English)》2023,62(38):e202309116
Although controlled radical polymerization is an excellent tool to make precision polymeric materials, reversal of the process to retrieve the starting monomer is far less explored despite the significance of chemical recycling. Here, we investigate the bulk depolymerization of RAFT and ATRP-synthesized polymers under identical conditions. RAFT-synthesized polymers undergo a relatively low-temperature solvent-free depolymerization back to monomer thanks to the partial in situ transformation of the RAFT end-group to macromonomer. Instead, ATRP-synthesized polymers can only depolymerize at significantly higher temperatures (>350 °C) through random backbone scission. To aid a more complete depolymerization at even lower temperatures, we performed a facile and quantitative end-group modification strategy in which both ATRP and RAFT end-groups were successfully converted to macromonomers. The macromonomers triggered a lower temperature bulk depolymerization with an onset at 150 °C yielding up to 90 % of monomer regeneration. The versatility of the methodology was demonstrated by a scalable depolymerization (≈10 g of starting polymer) retrieving 84 % of the starting monomer intact which could be subsequently used for further polymerization. This work presents a new low-energy approach for depolymerizing controlled radical polymers and creates many future opportunities as high-yielding, solvent-free and scalable depolymerization methods are sought. 相似文献
476.
Tuyen Trung Truong 《Mathematical Physics, Analysis and Geometry》2009,12(2):157-180
We determine the degree complexity for all elements of a family k
F
of birational maps which was introduced and studied in Bedford et al. (Math Phys Anal Geom 11:53–71, 2008).
相似文献
477.
M.P. Singh K.D. Truong P. Rauwel L.P. Carignan 《Journal of magnetism and magnetic materials》2009,321(11):1743-1747
Double perovskites provide a unique opportunity to induce and control multiferroic behaviours in oxide systems. The appealing possibility to design materials with a strong coupling between the magnetization and the polarization fields may be achieved in this family since these magnetic insulators can present structural self-ordering in the appropriate growth conditions. We have studied the functional properties of La2CoMnO6 and Bi2CoMnO6 epitaxial thin films grown by pulsed laser deposition. Cation-ordered La2CoMnO6 films display a magnetic Curie temperature of 250 K while cation-disordered Bi2CoMnO6 films present ferromagnetism up to ∼800 K. Such high transition temperature for magnetic ordering can be further tuned by varying the strain in the films indicating an important contribution from the structural characteristics of the materials. Our approach might be generalized for other oxide systems. At this end, our results are compared with other multiferroic systems. The roles of various cations, their arrangements and structural effects are further discussed. 相似文献
478.
Truong Minh Duc 《Optics Communications》2008,281(10):2842-2848
We have studied a higher-order squeezing and a higher-order sub-Poissonian photon statistics in photon-added coherent states. We obtained analytic forms of the degree of higher-order squeezing and the degree of higher-order sub-Poissonian statistics. We show that the photon-added coherent state |α,m〉 exhibits both higher-order squeezing and higher-order sub-Poissonian character. For two different types of higher-order squeezing, the degree of squeezing becomes bigger when the added photon number is increased. In single-photon-added coherent state, the degree of squeezing depends upon the order of squeezing N. When N is increased, the degree of squeezing becomes bigger in the Hong-Mandel-type higher-order squeezing but becomes smaller in the Hillery-type higher-order squeezing. Also, the higher-order sub-Poissonian character is more pronounced than the usual sub-Poissonian character in the single-photon-added coherent state. 相似文献
479.
Huy Truong Nguyen Kim Long Vu-Huynh Hien Minh Nguyen Huong Thuy Le Thi Hong Van Le Jeong Hill Park Minh Duc Nguyen 《Molecules (Basel, Switzerland)》2021,26(17)
Panax vietnamensis, or Vietnamese ginseng (VG), an endemic Panax species in Vietnam, possesses a unique saponin profile and interesting biological activities. This plant is presently in danger of extinction due to over-exploitation, resulting in many preservation efforts towards the geographical acclimatization of VG. Yet, no information on the saponin content of the acclimatized VG, an important quality indicator, is available. Here, we analyzed the saponin content in the underground parts of two- to five-year-old VG plants acclimatized to Lam Dong province. Nine characteristic saponins, including notoginsenoside-R1, ginsenoside-Rg1, -Rb1, -Rd, majonoside-R1, -R2 vina-ginsenoside-R2, -R11, and pseudoginsenoside-RT4, were simultaneously determined by HPLC coupled with UV and with a charged aerosol detector (CAD). Analyzing the results illustrated that the detection of characteristic ocotillol-type saponins in VG by CAD presented a superior capacity compared with that of UV, thus implying a preferential choice of CAD for the analysis of VG. The quantitative results indicating the saponin content in the underground parts of VG showed an increasing tendency from two to five years old, with the root and the rhizome exhibiting different saponin accumulation patterns. This is the first study that reveals the preliminary success of VG acclimatization and thereby encourages the continuing efforts to develop this valuable saponin-rich plant. 相似文献
480.
Valentina Bellotti Hyun Suk Wang Prof. Nghia P. Truong Prof. Roberto Simonutti Prof. Athina Anastasaki 《Angewandte Chemie (International ed. in English)》2023,62(45):e202313232
A photocatalytic RAFT-controlled radical depolymerization method is introduced for precisely conferring temporal control under visible light irradiation. By regulating the deactivation of the depropagating chains and suppressing thermal initiation, an excellent temporal control was enabled, exemplified by several consecutive “on” and “off” cycles. Minimal, if any, depolymerization could be observed during the dark periods while the polymer chain-ends could be efficiently re-activated and continue to depropagate upon re-exposure to light. Notably, favoring deactivation resulted in the gradual unzipping of polymer chains and a stepwise decrease in molecular weight over time. This synthetic approach constitutes a simple methodology to modulate temporal control during the chemical recycling of RAFT-synthesized polymers while offering invaluable mechanistic insights. 相似文献