全文获取类型
收费全文 | 2934篇 |
免费 | 88篇 |
国内免费 | 12篇 |
专业分类
化学 | 2296篇 |
晶体学 | 41篇 |
力学 | 25篇 |
数学 | 54篇 |
物理学 | 618篇 |
出版年
2022年 | 13篇 |
2021年 | 24篇 |
2020年 | 21篇 |
2019年 | 31篇 |
2018年 | 16篇 |
2017年 | 23篇 |
2016年 | 49篇 |
2015年 | 45篇 |
2014年 | 53篇 |
2013年 | 102篇 |
2012年 | 156篇 |
2011年 | 182篇 |
2010年 | 93篇 |
2009年 | 100篇 |
2008年 | 162篇 |
2007年 | 175篇 |
2006年 | 151篇 |
2005年 | 168篇 |
2004年 | 146篇 |
2003年 | 132篇 |
2002年 | 104篇 |
2001年 | 104篇 |
2000年 | 76篇 |
1999年 | 69篇 |
1998年 | 35篇 |
1997年 | 39篇 |
1996年 | 36篇 |
1995年 | 30篇 |
1994年 | 26篇 |
1993年 | 27篇 |
1992年 | 41篇 |
1991年 | 31篇 |
1990年 | 38篇 |
1989年 | 27篇 |
1988年 | 18篇 |
1987年 | 35篇 |
1986年 | 19篇 |
1985年 | 34篇 |
1984年 | 36篇 |
1983年 | 20篇 |
1982年 | 36篇 |
1981年 | 32篇 |
1980年 | 22篇 |
1979年 | 43篇 |
1978年 | 27篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1975年 | 18篇 |
1974年 | 19篇 |
1973年 | 15篇 |
排序方式: 共有3034条查询结果,搜索用时 15 毫秒
311.
Y. Watanabe H. Yamaguchi M. Hashinokuchi K. Sawabe S. Maruyama Y. Matsumoto K. Shobatake 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(1):103-109
The scattering of a hyperthermal Xe from a graphite (0001) surface
has been studied using a molecular beam-surface scattering technique
and molecular dynamics (MD) simulations.
The angular and velocity distributions of scattered Xe atoms
were measured at incidence energies from 0.45 to 3.5 eV,
three incidence angles of 15°, 35° and 60°
and the surface temperatures of 300 K and 550 K.
The observed time-of-flight spectra exhibit a sharp velocity distribution
with only one velocity component, which is ascribed
to the direct inelastic scattering process.
The angle-resolved energy ratios of the mean final translational energy
over the mean incidence energy Ef/Ei agree well
with those predicted based on the assumption of the conservation
of the momentum parallel to the surface.
The Hard-Cube model, where the mass of the cube is approximately 310 u,
has reproduced the angle-resolved flux distributions of scattered Xe atoms.
In the Hard-Cube model
almost 80% of the normal component of the incidence translational energy is found
to be lost in collision.
The MD simulations reproduce well the experimental results
by using the Brenner potential for intralayer C atoms
and a Lennard-Jones potential for interlayer C–C pair interactions. 相似文献
312.
Tadashi Miyasaka Hiromichi Tanaka Kazue Satoh Mie Imahashi Kentaro Yamaguchi Yoichi Iitaka 《Journal of heterocyclic chemistry》1987,24(3):873-875
A highly efficient intramolecular nitrene insertion was observed upon irradiation of 6-azidouridine derivatives. The N6,2′-cyclo structure of the product was determined unequivocally by X-ray crystallography. 相似文献
313.
Three isolectins were isolated from seeds of Erythrina variegata (Linn.) var. Orientalis by ion-exchange chromatography, followed by affinity chromatography on lactose-Sepharose 4B and acid-treated Sepharose 4B columns. The purified isolectins (EVLI, EVLII and EVLIII) are all specific for galactopyranosides and N-acetylgalactosamine, and their affinities for simple sugars are EVLIII greater than EVLII greater than EVLI. EVLI and EVLIII are homodimers made up of an A-subunit of molecular mass 36,000 and a B-subunit of molecular mass 33,000, whereas EVLII is a heterodimer composed of the A- and B-subunits. Upon treatment with trifluoromethansulphonic acid, the molecular masses of both subunits decreased to 31,000. Rechromatography of EVLII on the acid-treated Sepharose 4B column again produced the homodimeric lectins (EVLI and EVLIII). It is suggested that the constituent subunits of Erythrina variegata isolectins are eschangeable with each other in vitro. 相似文献
314.
H. Segawa S. Yamaguchi Y. Yamazaki T. Yano S. Shibata H. Misawa 《Applied Physics A: Materials Science & Processing》2006,83(3):447-451
Two-dimensional (2D) pillar arrays with submicrometer to micrometer repetitions have been fabricated from hybrid organic–inorganic
material by mask lithography or multi-beam interference lithography. The type of array structure depends on structural parameters
such as the pillar height, diameter and distance between neighboring pillars. Two kinds of periodic arrays, 2D arrays and
‘top-gathering’ arrays, can be obtained by controlling the structural parameters. In the top-gathering arrays, the pillars
are gathered at the top by means of self-organization, and ‘top-gathering’ units composed of four pillars can be formed.
PACS 68.35.Gy; 81.20.Fw; 82.50.-m 相似文献
315.
Summary The vibrations of a circular cylindrical shell reinforced with viscoelastic rings are theoretically treated. The frequency equation is derived using the transfer matrix together with the stiffness matrix. The numerical example surveys the damping effect of viscoelastic rings upon the dynamic behavior of the system.
Übersicht Die Schwingungen einer durch viskoelastische Kreisringe versteiften dünnwandigen Kreiszylinderschale werden theoretisch behandelt. Die Frequenzgleichung wird durch eine Kombination der Übertragungsmatrix mit der Steifigkeitsmatrix abgeleitet. An numerischen Beispielen wird ein Überblick über die dämpfende Wirkung der viskoelastischen Kreisringe auf das dynamische Verhalten des Systems gewonnen.相似文献
316.
The relationship between contact pressure and sinkage must be represented by a mathematical model to estimate the sinkage and the motion resistance due to a vehicle. In this study an approximate and simple pressure-sinkage model is proposed. This model takes into account the effect of the size of the penetration plate on soil response, and includes two soil values that can be obtained by a single plate penetration test. It is submitted that the sinkage and the motion resistance of a tracked vehicle can be estimated by means of the proposed model. 相似文献
317.
Hydrogen Production from a Methanol–Water Solution Catalyzed by an Anionic Iridium Complex Bearing a Functional Bipyridonate Ligand under Weakly Basic Conditions
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Prof. Dr. Ken‐ichi Fujita Dr. Ryoko Kawahara Takuya Aikawa Prof. Dr. Ryohei Yamaguchi 《Angewandte Chemie (International ed. in English)》2015,54(31):9057-9060
An efficient catalytic system for the production of hydrogen from a methanol–water solution has been developed using a new anionic iridium complex bearing a functional bipyridonate ligand as a catalyst. This system can be operated under mild conditions [weakly basic solution (0.046 mol L?1 NaOH) below 100 °C] without the use of an additional organic solvent. Long‐term continuous hydrogen production from a methanol–water solution catalyzed by the anionic iridium complex was also achieved. 相似文献
318.
Back Cover: CH Activation Generates Period‐Shortening Molecules That Target Cryptochrome in the Mammalian Circadian Clock (Angew. Chem. Int. Ed. 24/2015)
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Tsuyoshi Oshima Dr. Iori Yamanaka Dr. Anupriya Kumar Dr. Junichiro Yamaguchi Dr. Taeko Nishiwaki‐Ohkawa Kei Muto Rika Kawamura Dr. Tsuyoshi Hirota Prof. Dr. Kazuhiro Yagita Prof. Dr. Stephan Irle Prof. Dr. Steve A. Kay Prof. Dr. Takashi Yoshimura Prof. Dr. Kenichiro Itami 《Angewandte Chemie (International ed. in English)》2015,54(24):7200-7200
319.
320.
Supramolecular Polyelectrolyte Complexes of Bone Morphogenetic Protein‐2 with Sulfonated Polyrotaxanes to Induce Enhanced Osteogenic Differentiation
下载免费PDF全文
![点击此处可从《Macromolecular bioscience》网站下载免费的PDF全文](/ch/ext_images/free.gif)