全文获取类型
收费全文 | 3378篇 |
免费 | 62篇 |
国内免费 | 8篇 |
专业分类
化学 | 2101篇 |
晶体学 | 40篇 |
力学 | 24篇 |
数学 | 115篇 |
物理学 | 723篇 |
无线电 | 445篇 |
出版年
2022年 | 22篇 |
2021年 | 18篇 |
2020年 | 29篇 |
2019年 | 32篇 |
2018年 | 33篇 |
2017年 | 16篇 |
2016年 | 54篇 |
2015年 | 40篇 |
2014年 | 56篇 |
2013年 | 116篇 |
2012年 | 105篇 |
2011年 | 114篇 |
2010年 | 74篇 |
2009年 | 88篇 |
2008年 | 182篇 |
2007年 | 144篇 |
2006年 | 172篇 |
2005年 | 177篇 |
2004年 | 190篇 |
2003年 | 160篇 |
2002年 | 120篇 |
2001年 | 79篇 |
2000年 | 68篇 |
1999年 | 78篇 |
1998年 | 48篇 |
1997年 | 44篇 |
1996年 | 63篇 |
1995年 | 72篇 |
1994年 | 45篇 |
1993年 | 44篇 |
1992年 | 77篇 |
1991年 | 60篇 |
1990年 | 53篇 |
1989年 | 47篇 |
1988年 | 45篇 |
1987年 | 46篇 |
1986年 | 46篇 |
1985年 | 49篇 |
1984年 | 59篇 |
1983年 | 34篇 |
1982年 | 53篇 |
1981年 | 50篇 |
1980年 | 47篇 |
1979年 | 42篇 |
1978年 | 30篇 |
1977年 | 31篇 |
1976年 | 25篇 |
1975年 | 29篇 |
1974年 | 25篇 |
1973年 | 33篇 |
排序方式: 共有3448条查询结果,搜索用时 9 毫秒
31.
K. Hirose M. Ejima T. Fujibayashi Y. Fujii K. Futatsukawa O. Hashimoto T. Ishikawa S. Kameoka H. Kanda F. Kato S. Kinoshita T. Kinoshita T. Kon O. Konno K. Maeda A. Matsumura Y. Miura F. Miyahara H. Miyase T. Nakabayashi S.N. Nakamura H. Nomura K. Nonaka A. Ohtani Y. Okayasu M. Oyamada A. Sasaki H. Shimizu T. Takahashi T. Tamae H. Tamura T. Terasawa H. Tsubota K. Tsukada D. Uchida M. Ukai M. Wakamatsu T. Watanabe H. Yamauchi H. Yamazaki K. Yawata 《Physics letters. [Part B]》2009
32.
33.
Density fluctuations resulting from spinodal decomposition in a nonequilibrium first-order chiral phase transition are explored. We show that such instabilities generate divergent fluctuations of conserved charges along the isothermal spinodal lines appearing in the coexistence region. Thus, divergent density fluctuations could be a signal not only for the critical end point but also for the first-order phase transition expected in strongly interacting matter. We also compute the mean-field critical exponent at the spinodal lines. Our analysis is performed in the mean-field approximation to the Nambu-Jona-Lasinio model formulated at finite temperature and density. However, our main conclusions are expected to be generic and model independent. 相似文献
34.
We study the effects of Lorentz non-invariance on the physical pion velocity at the critical temperature Tc in an effective theory of hidden local symmetry (HLS) with the “vector manifestation” fixed point. We match at a “matching scale” ΛM the axial-vector current correlator in the HLS with the one in the operator product expansion for QCD, and present the matching condition to determine the bare pion velocity. We find that the physical pion velocity, which is found to be one at T=Tc when starting from the Lorentz invariant bare HLS, remains close to one with the Lorentz non-invariance, vπ(Tc)=0.83–0.99. This result is quite similar to the pion velocity in dense matter. 相似文献
35.
T. Sasaki C. Liang W.T. Nichols Y. Shimizu N. Koshizaki 《Applied Physics A: Materials Science & Processing》2004,79(4-6):1489-1492
Nanoparticles of TiO2 and SnO2 were obtained by laser ablation of Ti and Sn targets in both deionized water and sodium dodecyl sulfate (SDS) solutions. The crystallinity of the nanoparticles strongly depended on the SDS concentration in the solution. Well-crystallized oxide nanoparticles were most abundantly fabricated in SDS solution with around the critical micelle concentration. An inorganic/organic layered nanocomposite consisting of a zinc hydroxide layer and a SDS lamellar interlayer was obtained by the ablation of Zn in SDS solutions. The oxide and/or hydroxide can be formed by the rapid reactive quenching with water in the liquid–plasma interface, where ablated species can be oxidized by aqueous oxidation. The surfactant in the liquid medium could affect the aggregation and growth of nuclei after the oxidation. The preparation of Pt/TiO2 nanocomposite particles by PLA of the bi-combinant target of Pt and TiO2 is also reported. PACS 81.16.Mk; 81.10.Dn; 81.07.Bc 相似文献
36.
Y. Tanabe T. Adachi H. Sato T. Sasaki Y. Koike 《Journal of Physics and Chemistry of Solids》2008,69(12):3217-3220
We have measured the temperature dependence of the magnetic susceptibility, χ vs. T, and the magnetization curve, M vs. H, for NbSe2 single crystals, in order to compare the superconducting (SC) state in the overdoped regime of La2−xSrxCuO4 (LSCO) with the SC state of the layered conventional superconductor NbSe2. While a plateau in χ vs. T in a moderate magnetic field and a so-called second peak in M vs. H, which is due to the marked enhancement of vortex pinning, have been observed in the overdoped regime of LSCO, these behaviors have not been observed in NbSe2. The present results indicate that the anomalously marked enhancement of vortex pinning is a characteristic feature in the overdoped LSCO where a microscopic phase separation into SC and normal-state regions takes place. 相似文献
37.
A laser Doppler imaging system with a TV camera has been constructed and velocity distributions of fluid flow in cross sections of a rectangular channel have been measured. Consequently, it has been found that the system has some advantages in comparison with usual laser Doppler velocimeters, for example, the visualization of flow can be easily achieved. 相似文献
38.
Reizo Kato Hayao Kobayashi Takehiko Mori Akiko Kobayashi Yukiyoshi Sasaki 《Solid State Communications》1985,55(5):387-392
In the crystals of the cation radical salts based on the organic donor BMDT-TTF, the charge separation is observed. This comes from (1) nonequivalency of the site potential and (2) the long range electron-electron interaction, which are related to the two-dimensional nature of the molecular arrangement. The effects of the charge separation on the elctronic structure are discussed. 相似文献
39.
Nobuo Yoshida 《Probability Theory and Related Fields》1999,115(1):1-40
We consider a ferromagnetic spin system with unbounded interactions on the d-dimensional integer lattice (d > 1). Under mild assumptions on the one-body interactions (so that arbitrarily deep double wells are allowed), we prove that
if the coupling constants are small enough, then the finite volume Gibbs states satisfy the log-Sobolev inequality uniformly
in the volume and the boundary condition.
Received: 11 November 1997 / Revised version: 17 July 1998 相似文献
40.
Takeshi Kimura Shinya Ito Takashi Sasaki Satoshi Ogawa Ryu Sato Yasushi Kawai 《Heteroatom Chemistry》2008,19(4):394-401
4,9‐Diethyl[1,4]dihydrodithiino[5,6‐f]benzotrithiole (DTBT) gave a radical cation, DTBT(•+), and a dication, DTBT(2+), on treatment with a single‐electron oxidizing reagent. Both compounds showed an ESR signal, whereas the dication, generated by this procedure, was silent for 1H NMR. Hydrolysis of DTBT(2+) gave DTBT 1‐oxide (DTBT 1‐O) and 2‐oxide (DTBT 2‐O) together with DTBT and a mixture of several dioxides. A singlet‐state dication, DTBT(2+)‐S, which was generated upon treatment of DTBT 5‐oxide (DTBT 5‐O) with concentrated D2SO4, was detected by 1H and 13C NMR. After 20 h, the NMR signals disappeared while the solution was active for ESR. The results suggest that (i) a species generated from DTBT by oxidation with the single‐electron oxidizing reagent is a triplet‐state dication, DTBT(2+)‐T, and (ii) DTBT(2+)‐S, initially generated, gradually isomerizes to DTBT(2+)‐T in the solution, and DTBT(2+)‐T forms a partial spin pair. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:394–401, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20445 相似文献