全文获取类型
收费全文 | 1765篇 |
免费 | 31篇 |
国内免费 | 10篇 |
专业分类
化学 | 1138篇 |
晶体学 | 15篇 |
力学 | 17篇 |
数学 | 219篇 |
物理学 | 417篇 |
出版年
2020年 | 14篇 |
2019年 | 13篇 |
2016年 | 22篇 |
2015年 | 22篇 |
2014年 | 26篇 |
2013年 | 39篇 |
2012年 | 68篇 |
2011年 | 59篇 |
2010年 | 48篇 |
2009年 | 30篇 |
2008年 | 66篇 |
2007年 | 50篇 |
2006年 | 76篇 |
2005年 | 47篇 |
2004年 | 46篇 |
2003年 | 33篇 |
2002年 | 47篇 |
2001年 | 36篇 |
2000年 | 38篇 |
1999年 | 25篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 28篇 |
1995年 | 45篇 |
1994年 | 38篇 |
1993年 | 27篇 |
1992年 | 28篇 |
1991年 | 25篇 |
1990年 | 27篇 |
1989年 | 20篇 |
1988年 | 32篇 |
1987年 | 21篇 |
1986年 | 23篇 |
1985年 | 26篇 |
1984年 | 22篇 |
1983年 | 16篇 |
1982年 | 15篇 |
1981年 | 32篇 |
1980年 | 22篇 |
1979年 | 16篇 |
1978年 | 32篇 |
1977年 | 25篇 |
1976年 | 27篇 |
1975年 | 20篇 |
1974年 | 28篇 |
1973年 | 28篇 |
1972年 | 13篇 |
1970年 | 20篇 |
1967年 | 15篇 |
1965年 | 17篇 |
排序方式: 共有1806条查询结果,搜索用时 0 毫秒
991.
992.
Milton SV Gluskin E Biedron SG Dejus RJ Den Hartog PK Galayda JN Kim K Lewellen JW Moog ER Sajaev V Sereno NS Travish G Vinokurov NA Arnold ND Benson C Berg W Biggs JA Borland M Carwardine JA Chae Y Decker G Deriy BN Erdmann MJ Friedsam H Gold C Grelick AE 《Physical review letters》2000,85(5):988-991
Experimental evidence for self-amplified spontaneous emission (SASE) at 530 nm is reported. The measurements were made at the low-energy undulator test line facility at the Advanced Photon Source, Argonne National Laboratory. The experimental setup and details of the experimental results are presented, as well as preliminary analysis. This experiment extends to shorter wavelengths the operational knowledge of a linac-based SASE free-electron laser and explicitly shows the predicted exponential growth in intensity of the optical pulse as a function of length along the undulator. 相似文献
993.
In a strong laser field, electrons tunnel from an atom at a rate determined by the instantaneous field. If the pulse is only a few cycles in duration, the highly nonlinear nature of tunnel ionization ensures that the resultant electron wave packet is primarily formed in less than one period. Measuring the direction of above-threshold-ionization electrons produced by circularly polarized light provides a direct method of measuring the absolute carrier phase of a single pulse. The method is robust, surviving spatial and temporal integration as well as intensity fluctuations. 相似文献
994.
995.
The experimental realization of thermocapillary flow without return flow is reported. This type of flow (linear flow) was proposed and analyzed theoretically by Smith and Davis (J. Fluid Mech., 132:119–144, 1983). We suppressed the return flow by providing channels and side channels with lower flow resistance compared to that of the return flow. Cooling the layer with linear flow from above results in the Marangoni instability of longitudinal rolls as the most dangerous mode. Strong linear flow stabilizes the system against longitudinal rolls. We report preliminary results on the threshold and on the wavelength of the longitudinal rolls. 相似文献
996.
Tim Hawly Fabian Streller Manuel Johnson Dr. Sandra Miguez-Lago Dr. Natalie Hammer Dr. Frank Hampel Dustin Vivod Prof. Dr. Dirk Zahn Prof. Dr. Milan Kivala Robert Branscheid Prof. Dr. Erdmann Spiecker Prof. Dr. Rainer H. Fink 《Chemphyschem》2021,22(11):1079-1087
The ability of a series of bridged triarylamines, so-called N-heterotriangulenes, to form multilayer-type 2D-extended films via a solution-based processing method was examined using complementary microscopic techniques. We found that the long-range order, crystallinity, and layer thickness decisively depend on the nature of the substituents attached to the polycyclic backbone. Owing to their flat core unit, compounds exhibiting a carbonyl unit at the bridge position provide a superior building block as compared to thioketone-bridged derivatives. In addition, nature and length of the peripheral substituents affect the orientation of the aromatic core unit within highly crystalline films. Hence, our results stress the significance of a suitable molecular framework and provide deeper understanding of structure formation in 2D-confined surroundings for such compounds. 相似文献
997.
Yuan Liu Prof. Dr. Shuangyang Ding Dr. Richard Dietrich Prof. Dr. Erwin Märtlbauer Dr. Kui Zhu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(6):1508-1512
The emergence and rapid spread of methicillin‐resistant Staphylococcus aureus (MRSA) poses a serious threat to public health. New antibiotics and strategies are urgently needed to combat S. aureus associated infections. Bacaucin, a novel cyclic lipopeptide from Bacillus subtilis CAU21, is reported. Bacaucin shows broad antibacterial activity against Gram‐positive bacteria, but is also hemolytic and cytotoxic. However, bacaucin‐1, a bacaucin‐inspired ring‐opened heptapeptide, shows specific antibacterial activity against MRSA by a membrane‐disruptive mechanism without detectable toxicity to mammalian cells or induction of bacterial resistance. Bacaucin‐1 was efficient in preventing infections in both in vitro and in vivo models and is a valuable prototype antibiotic with high potential against S. aureus infections. 相似文献
998.
Let G and H be Lie groups with Lie algebras
and
. Let G be connected. We prove that a Lie algebra homomorphism
is exact if and only if it is completely positive. The main resource is a corresponding theorem about representations on
Hilbert spaces.
This article summarizes the main results of [1].
Received: 6 December 2005 相似文献
999.
We calculate the solvation free energy of proteins in the tube model of Banavar and Maritan [Rev. Mod. Phys. 75, 23 (2003)10.1103/RevModPhys.75.23] using morphological thermodynamics which is based on Hadwiger's theorem of integral geometry. Thereby we extend recent results by Snir and Kamien [Science 307, 1067 (2005)10.1126/science.1106243] to hard-sphere solvents at finite packing fractions and obtain new conclusions. Depending on the solvent properties, parameter regions are identified where the beta sheet, the optimal helix, or neither is favored. 相似文献
1000.
We consider a nonspherical colloidal particle immersed in a fluid close to its critical point. The temperature dependence of the corresponding order parameter profile is calculated explicitly. We perform a systematic expansion of the order parameter profile in powers of the local curvatures of the surface of the colloidal particle. This curvature expansion reduces to the short distance expansion of the order parameter profile in the case that the solvent is at the critical composition. 相似文献