全文获取类型
收费全文 | 2958篇 |
免费 | 82篇 |
国内免费 | 7篇 |
专业分类
化学 | 2258篇 |
晶体学 | 50篇 |
力学 | 21篇 |
数学 | 145篇 |
物理学 | 573篇 |
出版年
2023年 | 18篇 |
2022年 | 24篇 |
2021年 | 35篇 |
2020年 | 66篇 |
2019年 | 48篇 |
2018年 | 45篇 |
2017年 | 30篇 |
2016年 | 77篇 |
2015年 | 58篇 |
2014年 | 93篇 |
2013年 | 140篇 |
2012年 | 201篇 |
2011年 | 254篇 |
2010年 | 128篇 |
2009年 | 118篇 |
2008年 | 214篇 |
2007年 | 202篇 |
2006年 | 203篇 |
2005年 | 196篇 |
2004年 | 165篇 |
2003年 | 138篇 |
2002年 | 138篇 |
2001年 | 43篇 |
2000年 | 34篇 |
1999年 | 22篇 |
1998年 | 28篇 |
1997年 | 24篇 |
1996年 | 30篇 |
1995年 | 19篇 |
1994年 | 20篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 9篇 |
1990年 | 14篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 17篇 |
1982年 | 19篇 |
1981年 | 12篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 4篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有3047条查询结果,搜索用时 15 毫秒
991.
Dibenzo[a,j]phenazine‐Cored Donor–Acceptor–Donor Compounds as Green‐to‐Red/NIR Thermally Activated Delayed Fluorescence Organic Light Emitters 下载免费PDF全文
Dr. Przemyslaw Data Piotr Pander Masato Okazaki Prof. Dr. Youhei Takeda Prof. Dr. Satoshi Minakata Prof. Dr. Andrew P. Monkman 《Angewandte Chemie (International ed. in English)》2016,55(19):5739-5744
A new family of thermally activated delayed fluorescence (TADF) emitters based on U‐shaped D‐A‐D architecture with a novel accepting unit has been developed. All investigated compounds have small singlet‐triplet energy splitting (ΔEST) ranging from 0.02 to 0.20 eV and showed efficient TADF properties. The lowest triplet state of the acceptor unit plays the key role in the TADF mechanism. OLEDs fabricated with these TADF emitters achieved excellent efficiencies up to 16 % external quantum efficiency (EQE). 相似文献
992.
Characterization of the Cytochrome c Membrane‐Binding Site Using Cardiolipin‐Containing Bicelles with NMR 下载免费PDF全文
Hisashi Kobayashi Dr. Satoshi Nagao Prof. Dr. Shun Hirota 《Angewandte Chemie (International ed. in English)》2016,55(45):14019-14022
Cytochrome (cyt) c transports electrons from Complex III to Complex IV in mitochondria. Cyt c is ordinarily anchored to the mitochondrial membrane through interaction with cardiolipin (CL), however its release into the cytosol initiates apoptosis. The cyt c interaction site with CL‐containing bicelles was characterized by NMR spectroscopy. Chemical shift perturbations in cyt c signals upon interaction with bicelles revealed that a relatively wide region, which includes the A‐site, the CXXCH motif, and the N‐ and C‐terminal helices, and contains multiple Lys residues, interacts cooperatively with CL. The specific cyt c–CL interaction increased with increasing CL molecules in the bicelles. The location of the cyt c interaction site for CL was similar to those for Complex III and Complex IV, thus indicating that cyt c recognizes lipids and partner proteins in a similar way. In addition to elucidating the cyt c membrane‐binding site, these results provide insight into the dynamic aspect of cyt c interactions in mitochondria. 相似文献
993.
Several studies have used microwaves as a heat source for carrying out various types of reactions employing circulation reaction vessels. The microwave flow chemical synthesis methodology is most appropriate in the use of microwaves in chemical syntheses. It can attenuate the problem of microwave heating (non‐uniform heating and penetration depth) and maximize the benefits (rapid heating and first temperature adjustments). In this brief review, we examine and explain some of the relevant features of microwave heating with applicative examples of the usage of microwave flow chemistry equipment in carrying out organic syntheses, enzymatic reactions, and (not least) nanoparticle syntheses. 相似文献
994.
Hiroshi Tsukube Prof. Dr. Yuki Noda Satoshi Shinoda Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(14):4273-4278
The apoferritin protein and apoferritin–Tb3+ complex were demonstrated to form oligomeric and polymeric self‐assemblies in neutral aqueous solutions, based on characterization by using luminescence and UV/Vis spectroscopy, dynamic light scattering, and transmission electron microscopy. Addition of a 20‐mer or higher poly(arginine) to the solution resulted in coprecipitation through nanoscale interactions, while biological proteins and other poly(amino acids) rarely yielded precipitates under the conditions employed. The apoferritin–Tb3+ complex assembly exhibited a particularly long‐lived green luminescence in aqueous solution, and its poly(arginine)‐selective precipitation behavior was followed by monitoring the changes in luminescence. The poly(arginine)‐tagged albumin precipitated selectively and quantitatively, so that the apoferritin–Tb3+ complex can function as a new luminescent biotool for the sensing of poly(arginine) and its protein conjugates. 相似文献
995.
The 1(01)-0(00), 2(02)-1(01), and 3(03)-2(02) rotational transitions of the FCO radical are observed at 22.3, 44.5, and 66.8 GHz, respectively, using a Fourier transform millimeter-wave spectrometer with a pulsed discharge nozzle. The FCO radical is produced by discharging F(2)CO diluted in the Ar buffer gas. Twelve fine and hyperfine components for the three transitions are observed, and the effective rotational constant, the centrifugal distortion constant, the spin-rotation constant with its centrifugal correction term, and three hyperfine constants are determined. Furthermore, the vibrational satellites for the v(1)=1, v(2)=1, v(3)=1, and v(3)=2 states are also observed in the 22.3 GHz region. From the dipolar interaction constants, the principal axis of the dipolar interaction tensor is estimated and is discussed in relation to the distribution of the unpaired electron. Copyright 2001 Academic Press. 相似文献
996.
Three advanced CIELAB-based color-difference formulae, CMC, CIE94, and CIEDE2000, together with the basic CIELAB equation,
were tested using large color-difference visual data (maximum average size was 12 CIELAB ΔE units) produced in this study.
The color-difference comparison experiment was carried out at CIE Gray and Blue centers by a panel of 6 normal color-vision
observers using CRT-generated stimuli based on the psychophysical method of constant stimuli. The experimental data, processed
via probit analysis, were well fitted to chromaticity ellipses with a high reliance according to the observer accuracy in
terms ofPF/3 measure. A detailed comparison was performed to analyze the agreement between predicted color differences from all formulae
and their corresponding visual scales in all measurement planes of CIELAB space. The results show that the CIEDE2000 marginally
outperformed the others at all color centers while CIE94 was the worst in original formulae or with optimizedk
L value, but the CIELAB performed worst when the parametric factors ofk
L,kc, andk
H were all optimized, with the CMC always lying between these extremes. 相似文献
997.
Abstract Fibrous titania was synthesized by the solvothermal reactions of H1Ti4O9 nH2in different media. H2Ti4O9·nH2O transformed in steps to H2Ti8O17, monoclinic TiOz, anatase and rutile. The phase transformation temperature and microstructure of the products changed significantly depending on the heating environment. The critical temperature at which anatase appeared in liquid media was much lower than that in air. The titania fibers consisted of nanocrystals of TiO2. The crystallite size and crystallinity of titania decreased with decreasing the dielectric constant of the reaction medium. Consequently, the photocatalytic activity of titania changed with heat treatment media in the following sequence: ethanol, methanol > water > air, i.e., fibrous titania possessing excellent photocatalytic activity could be obtained by the solvothermal reactions using alcohol such as methanol and ethanol. Titania powders crystallized by the solvothermal reaction in methanol also possessed excellent thermal stability. 相似文献
998.
Satoshi Watanabe Tatsumasa Hiratsuka Yusuke Asahi Asumi Tanaka Kazuhiro Mae Minoru T. Miyahara 《Particle & Particle Systems Characterization》2015,32(2):234-242
Gold nanoshells with tunable surface plasmon resonances are a promising material for optical and biomedical applications. They are produced through seed‐mediated growth, in which gold nanoparticles (AuNPs) are seeded on the core particle surface followed by growth of the gold seeds into a shell. However, synthetic gold nanoshell production is typically a multistep, time‐consuming batch‐type process, and a simple and scalable process remains a challenge. In the present study, a continuous flow process for the seed‐mediated growth of silica–gold nanoshells is established by exploiting the excellent mixing performance of a microreactor. In the AuNP‐seeding step, the reduction of gold ions in the presence of core particles in the microreactor enables the one‐step flow synthesis of gold‐decorated silica particles through heterogeneous nucleation. Flow shell growth is also realized using the microreactor by selecting an appropriate reducing agent. Because self‐nucleation in the bulk solution phase is suppressed in the microreactor system, no washing is needed after each step, thus enabling the connection of the microreactors for the seeding and shell growth steps into a sequential flow process to synthesize gold nanoshells. The established system is simple and robust, thus making it a promising technology for producing gold nanoshells in an industrial setting. 相似文献
999.
Gold Nanoparticles: Fabrication of NIR‐Excitable SERS‐Active Composite Particles Composed of Densely Packed Au Nanoparticles on Polymer Microparticles (Part. Part. Syst. Charact. 4/2015) 下载免费PDF全文
1000.
Satoshi Takahashi 《Israel Journal of Mathematics》2002,127(1):1-17
The dimension spectrumH(δ) is a function characterizing the distribution of dimension of sections. Using the multifractal formula for sofic measures,
we show that the dimension spectra of irreducible self-affine sets (McMullen’s Carpet) coincide with the modified Legendre
transform of the free energy Ψd(β). This variational relation leads to the formula of Hausdorff dimension of self-affine sets, max(δ +H(δ)) = Ψd(η), whereη is the logarithmic ratio of the contraction rates of the affine maps. 相似文献