全文获取类型
收费全文 | 812篇 |
免费 | 26篇 |
国内免费 | 4篇 |
专业分类
化学 | 529篇 |
晶体学 | 3篇 |
力学 | 13篇 |
数学 | 67篇 |
物理学 | 230篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 6篇 |
2020年 | 19篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 13篇 |
2016年 | 22篇 |
2015年 | 10篇 |
2014年 | 19篇 |
2013年 | 42篇 |
2012年 | 38篇 |
2011年 | 33篇 |
2010年 | 29篇 |
2009年 | 23篇 |
2008年 | 50篇 |
2007年 | 55篇 |
2006年 | 44篇 |
2005年 | 34篇 |
2004年 | 51篇 |
2003年 | 22篇 |
2002年 | 26篇 |
2001年 | 28篇 |
2000年 | 27篇 |
1999年 | 22篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 3篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1973年 | 3篇 |
排序方式: 共有842条查询结果,搜索用时 769 毫秒
821.
A. Hirashima K. Shinkai E. Kuwano E. Taniguchi M. Eto 《SAR and QSAR in environmental research》2013,24(1):45-54
Abstract The quantitative structure-activity relationship of 39 octopamine (OA) agonists and 12 antagonists against the thoracic nerve cord of the migratory locust, Locusta migratoria L. was analyzed using atom based rigid fit method or flexible fitting offered by PowerFit 1.0 from MicroSimulation. For OA agonists, the more similar to reference compound NC (24) the structure of test compound, the higher the activity, whereas for OA antagonists it was not the case. Antagonists may not interact with the same part of the membrane with which the agonists interact. Taken the part of the membrane with which the agonist interacts as the true receptor, the antagonist may well interact with an area surrounding the receptor including the ionophore. 相似文献
822.
Guoyang Guan Shuhei Fukuoka Satoshi Yamashita Takashi Yamamoto Hiromi Taniguchi Yasuhiro Nakazawa 《Journal of Thermal Analysis and Calorimetry》2013,113(3):1197-1201
Thermodynamic investigation using the relaxation calorimetry technique and the microchip calorimetry technique is performed to clarify low-temperature behaviors of a radical cation salt consisting of a donor molecule of bispropylenedithiotetrathiafulvalene (BPDT-TTF) and a linear anion of ${{\text{ICl}}_{2}^{-}}$ ICl 2 ? . This compound has a layered structure similar to numerous BEDT-TTF compounds. The donor molecules form a dimerized arrangement in the layer. Temperature dependence of heat capacity obtained by the relaxation technique shows a broad hump structure around 20–25 K corresponding to the temperature where the magnetic susceptibility shows a drastic decrease due to the formation of the singlet spin state. The microchip calorimetry technique detected a step-like anomaly around 23 K in the temperature dependence of C p T ?1 of which entropy is evaluated as only few % of Rln2 corresponding to the full entropy of localized π-electrons located on each dimer unit. The negligibly small T-linear term in the low-temperature heat capacity and absence of magnetic fields dependence below 3.2 K predict opening of rigid gap structure in the spin excitations, which is consistent with a spin-singlet formation due to the formation of spin-Peierls type ordering or charge ordering state. 相似文献
823.
Noboru Taniguchi 《Separation & Purification Reviews》2013,42(2):247-299
The term “mucopolysaccharides” was originally introduced by Meyer to describe “hexosamine-containing heteropolysaccharides of animal origin occurring in a pure state or as protein salts”. Many of the names originally assigned to the mucopolysaccharides have since been revised in an effort to systematize the nomenclature (Table 1). Jeanloz2 in 1960 proposed the term “glycosaminoglycuronoglycans” in place of mucopolysaccharides as in most cases they are composed of amino sugars (glycosamino-) and uronic acids (glycurono-) joined in long chains(-glycans). For the sake of simplicity, the term “glycosaminoglycans” is getting acceptance in place of the rather lengthy term “glycosaminoglycuronoglycans” as well as the old and perhaps more familiar term “mucopolysaccharides”. As a matter of convenience, the term “polysaccharides” will be frequently used here, instead of glycosaminoglycans. 相似文献
824.
N. Momoshima F. Inoue T. Ohta Y. Mahara J. Shimada R. Ikawa M. Kagabu M. Ono K. Yamaguchi S. Sugihara M. Taniguchi 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(3):761-767
Groundwater age was determined by 85Kr/Kr specific activity of gases dissolved in groundwater at Kumamoto Area, in which newly developed Kr extraction system and liquid scintillation counting technique for 85Kr were applied. Apparent mean residence times observed were 8.2 ± 0.7 years and 20.7 ± 0.6 years for the groundwater taken from a well at the recharge area and that from an artesian borehole at the discharge area, respectively showing a consistent age trend estimated from the observed groundwater flow system of Kumamoto Area and also that determined using environmental tritium. Similar mean residence times of 85Kr and tritium were observed at the discharge area but the mean residence time of 85Kr at the recharge area was younger compared to that of tritium, probably due to mixing of river water containing recent 85Kr high in concentration into groundwater flow coming from the northern upland??s recharge area. The mean residence time of the groundwater flow coming from northern upland area and a traveling time of the groundwater between two sampling points were estimated by a simple model assuming mixing the river water with the groundwater and a piston flow between two sampling points. 相似文献
825.
Taniguchi T Zaimoku H Ishibashi H 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(15):4307-4312
A mild and practical oxyarylation of alkenes by oxidative radical addition has been developed by using aerobic oxidation of hydrazine compounds. The use of a catalytic amount of potassium ferrocyanide trihydrate (K4[Fe(CN)6]?3 H2O) and water accelerated this radical reaction to give peroxides or alcohols from simple alkenes in good yields. The environmentally friendly and economical radical reactions were achieved at room temperature in the presence of iron catalyst, oxygen gas, and water. A method involving aniline as a radical precursor is also described. 相似文献
826.
Yibo Wang Siqi Jiang Jingkuan Xiao Xiaofan Cai Di Zhang Ping Wang Guodong Ma Yaqing Han Jiabei Huang Kenji Watanabe Takashi Taniguchi Yanfeng Guo Lei Wang Alexander S. Mayorov Geliang Yu 《Frontiers of Physics》2022,17(4):43504
Van der Waals (vdW) assembly of two-dimensional materials has long been recognized as a powerful tool for creating unique systems with properties that cannot be found in natural compounds [Nature 499, 419 (2013)]. However, among the variety of vdW heterostructures and their various properties, only a few have revealed metallic and ferroelectric behaviour signatures [Sci. Adv. 5, eaax5080 (2019); Nature560, 336 (2018)]. Here we show ferroelectric semimetal made of double-gated double-layer graphene separated by an atomically thin crystal of hexagonal boron nitride. The structure demonstrates high room temperature mobility of the order of 10 m2·V−1·s−1 and exhibits ambipolar switching in response to the external electric field. The observed hysteresis is reversible and persists above room temperature. Our fabrication method expands the family of ferroelectric vdW compounds and offers a promising route for developing novel phase-changing devices. A possible microscopic model of ferroelectricity is discussed. 相似文献
827.
Inertial effects in fluctuations of the work to sustain a system in a nonequilibrium steady state are discussed for a dragged
massive Brownian particle model using a path integral approach. We calculate the work distribution function in the laboratory
and comoving frames and prove the asymptotic fluctuation theorem for these works for any initial condition. Important and
observable differences between the work fluctuations in the two frames appear for finite times and are discussed concretely
for a nonequilibrium steady state initial condition. We also show that for finite times a time oscillatory behavior appears
in the work distribution function for masses larger than a nonzero critical value. 相似文献
828.
Iwasawa H Douglas JF Sato K Masui T Yoshida Y Sun Z Eisaki H Bando H Ino A Arita M Shimada K Namatame H Taniguchi M Tajima S Uchida S Saitoh T Dessau DS Aiura Y 《Physical review letters》2008,101(15):157005
Angle-resolved photoemission spectroscopy with low-energy tunable photons along the nodal direction of oxygen isotope substituted Bi(2)Sr(2)CaCu(2)O(8+delta) reveals a distinct oxygen isotope shift near the electron-boson coupling "kink" in the electronic dispersion. The magnitude (a few meV) and direction of the kink shift are as expected due to the measured isotopic shift of phonon frequency, and are also in agreement with theoretical expectations. This demonstrates the participation of the phonons as dominant players, as well as pinpointing the most relevant of the phonon branches. 相似文献
829.
Ushiroda Y Sumisawa K Taniguchi N Adachi I Aihara H Arinstein K Aushev T Bahinipati S Bakich AM Balagura V Barberio E Belous K Bitenc U Bondar A Bozek A Bracko M Browder TE Chang P Chao Y Chen A Chen WT Cheon BG Chistov R Cho IS Choi Y Dalseno J Dash M Eidelman S Epifanov D Gabyshev N Golob B Ha H Haba J Hara K Hara T Hayasaka K Hazumi M Heffernan D Hokuue T Hoshi Y Hou WS Hyun HJ Inami K Ishikawa A Ishino H Itoh R Iwasaki Y Kah DH Kang JH Kawai H Kawasaki T Kichimi H Kim YJ Kinoshita K 《Physical review letters》2008,100(2):021602
We report the first measurement of CP-violation parameters in B0-->rho0gamma decays based on a data sample of 657x10(6)BB pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the time-dependent and direct CP-violating parameters, Srho0gamma=-0.83+/-0.65(stat)+/-0.18(syst) and Arho0gamma=-0.44+/-0.49(stat)+/-0.14(syst), respectively. 相似文献
830.
M. Ye Y. T. Cui Y. Nishimura Y. Yamada S. Qiao A. Kimura M. Nakatake H. Namatame M. Taniguchi 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,75(1):31-35
The edge properties of single layer graphene epitaxially grown on partially graphitized 4H-SiC(0001) surface have been investigated with scanning tunneling microscopy (STM). We directly observed the atomic-structure dependency of the super structures in the vicinity of armchair and zigzag edges due to the different kinds of symmetry-breaking at those two edges. 相似文献