全文获取类型
收费全文 | 540848篇 |
免费 | 6771篇 |
国内免费 | 2547篇 |
专业分类
化学 | 291335篇 |
晶体学 | 8392篇 |
力学 | 23086篇 |
综合类 | 66篇 |
数学 | 65519篇 |
物理学 | 161768篇 |
出版年
2020年 | 4272篇 |
2019年 | 4771篇 |
2018年 | 5943篇 |
2017年 | 6001篇 |
2016年 | 9218篇 |
2015年 | 6017篇 |
2014年 | 9089篇 |
2013年 | 24103篇 |
2012年 | 18302篇 |
2011年 | 22419篇 |
2010年 | 15552篇 |
2009年 | 15387篇 |
2008年 | 20660篇 |
2007年 | 20765篇 |
2006年 | 19456篇 |
2005年 | 17747篇 |
2004年 | 16036篇 |
2003年 | 14243篇 |
2002年 | 14056篇 |
2001年 | 15668篇 |
2000年 | 11862篇 |
1999年 | 9184篇 |
1998年 | 7722篇 |
1997年 | 7613篇 |
1996年 | 7327篇 |
1995年 | 6704篇 |
1994年 | 6607篇 |
1993年 | 6548篇 |
1992年 | 7152篇 |
1991年 | 7174篇 |
1990年 | 6798篇 |
1989年 | 6713篇 |
1988年 | 6686篇 |
1987年 | 6545篇 |
1986年 | 6286篇 |
1985年 | 8501篇 |
1984年 | 8730篇 |
1983年 | 7327篇 |
1982年 | 7930篇 |
1981年 | 7481篇 |
1980年 | 7241篇 |
1979年 | 7510篇 |
1978年 | 7895篇 |
1977年 | 7772篇 |
1976年 | 7953篇 |
1975年 | 7294篇 |
1974年 | 7473篇 |
1973年 | 7897篇 |
1972年 | 5465篇 |
1971年 | 4380篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
881.
Oksengendler B. L. Karimov M. Yunusov M. C. Karakhodzhaev A. K. 《Russian Physics Journal》2004,47(7):790-791
Russian Physics Journal - 相似文献
882.
Russian Physics Journal - 相似文献
883.
V. S. Gorelik P. P. Sverbil' A. B. Fadyushin V. V. Vasil'ev 《Journal of Russian Laser Research》2004,25(1):54-63
A possibility of application of semiconductor lasers of the visible range as exciting sources for Raman spectroscopy is studied. An experimental set-up for measuring Raman spectra of polycrystalline dielectrics and broad-gap semiconductors excited by a semiconductor laser with a wavelength of 640 nm was created. The conditions under which the spectral width of the lasing line of a semiconductor laser was within 10-3 cm-1 in the continuous mode with a power of 10 mW are realized. The characteristics of various types of exciting sources used in Raman spectroscopy are compared. The results of studies of the characteristic Raman spectra excited with a semiconductor laser in polycrystalline sulfur are presented. 相似文献
884.
The study of the effect of a perfectly conducting plane placed at a certain distance from the surface of a potassium niobate crystal on the characteristics of the generalized Rayleigh and Gulyaev-Bleustein surface waves is continued. In addition, the effect of an infinitely thin conducting layer applied to the surface of the piezoelectric on the characteristics of these waves is analyzed. It is found that a variation in the conductance of this layer can produce a result that completely differs from the result obtained when a perfectly conducting plane is moved toward the surface, although the extreme states of these actions (electrically open and short-circuited surfaces) are identical. A possible physical explanation of this difference is proposed. 相似文献
885.
L. A. Manakova 《Journal of Experimental and Theoretical Physics》2004,99(1):157-168
The mechanisms leading to instability of the non-Fermi-liquid state of a Luttinger liquid with two-level impurities are proposed. Since exchange scattering in 1D systems is two-channel scattering in a certain range of parameters, several types of non-Fermi-liquid excitations with different quantum numbers exist in the vicinity of the Fermi level. These excitations include, first, charge density fluctuations in the Luttinger liquid and, second, many-particle excitations due to two-channel exchange interaction, which are associated with band-type as well as impurity fermion states. It is shown that mutual scattering of many-particle excitations of various types leads to the emergence of an additional Fermi-liquid singularity in the vicinity of the Fermi level. The conditions under which the Fermi-liquid state with a new energy scale (which is much smaller than the Kondo temperature) is the ground state of the system are formulated. 相似文献
886.
Deeper insight into the features of a reactor as a source of antineutrinos is required for making further advances in studying the fundamental properties of the neutrino. The relationship between the thermal power of a reactor and the rate of the chain fission reaction in its core is analyzed. 相似文献
887.
S. A. Sadovsky Yu. V. Kharlov A. L. S. Angelis E. Gładysz-Dziaduś V. L. Korotkikh G. Mavromanolakis A. D. Panagiotou 《Physics of Atomic Nuclei》2004,67(2):396-405
A phenomenological model for describing the production of Centauro events in relativistic heavy-ion collisions is discussed. The model provides quantitative predictions for kinematical variables, for the baryon number, and for the masses of a Centauro fireball and of its decay products. A Centauro fireball decays predominantly into nucleons, strange hyperons, and possibly strangelets. Centauro events in Pb + Pb collisions at the LHC energy are simulated for the CASTOR detector. The signatures of these events are discussed in detail. 相似文献
888.
M. I. Adamovich V. Bradnova S. Vokal S. G. Gerasimov V. A. Dronov P. I. Zarubin A. D. Kovalenko K. A. Kotel'nikov V. A. Krasnov V. G. Larionova F. G. Lepekhin A. I. Malakhov G. I. Orlova N. G. Peresadko N. G. Polukhina P. A. Rukoyatkin V. V. Rusakova N. A. Salmanova B. B. Simonov M. M. Chernyavsky M. Haiduc S. P. Kharlamov L. Just 《Physics of Atomic Nuclei》2004,67(3):514-517
New results concerning the topology of the fragmentation of relativistic nuclei 7Li and 10B are presented. A program is proposed for studying the cluster structure of stable and radioactive nuclei. The use of emulsions in the investigation of nuclear clustering in the fragmentation of light nuclei at energies are in excess of 1 GeV per nucleon is discussed. 相似文献
889.
Mithlesh Kumar R. M. Kadam T. K. Seshagiri V. Natarajan A. G. Page 《Journal of Radioanalytical and Nuclear Chemistry》2004,262(3):633-637
Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) investigations were carried out on gamma irradiated SrBPO5 samples doped with CeO2 and co-doped with CeO2 and Sm2O3. On gamma-irradiation at room temperature, BO3
2–, O2
– and O– radicals were produced. It was seen that the O– radical ion disappeared in the sample annealed at 500 K. It is proposed that the recombination between trapped electrons and O– radical ions results in transfer of recombination energy to the impurity centre Ce3+ resulting in TSL glow peak at 485 K. In the case of co-doped samples energy transfer occurs between Ce3+ to Sm3+ resulting in increase in the intensity of glow peak at 485 K.The authors are grateful to Dr. V. K. Manchanda, Head, Radiochemistry Division, BARC for his keen interest and encouragement during the course of this work. 相似文献
890.
E. V. McCloskey A. Dey R. M. Parr N. Aras A. Balogh J. Bostock A. Borell S. Krishnan G. Lobo L. L. Qin Y. Zhang S. Cvijetic V. Zaichick M. Lim-Abraham K. Bose S. Wynchank G. V. Iyengar 《Journal of Radioanalytical and Nuclear Chemistry》2004,259(2):341-345
In 1994, the International Atomic Energy Agency (IAEA) initiated a 5-year Co-ordinated Research Project (CRP) to determine
geographical and racial differences in peak bone mineral density (BMD) in men and women aged 15-49 years. The study demonstrates
that there are distinct global differences in BMD at the hip and spine in both men and women approximating to one population
standard deviation between populations with the highest and lowest BMD. These differences persist following adjustments for
age, sex and body size. Such information is valuable in understanding the reasons for global differences in fracture rate
and predicting future trends in fracture incidence.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献