全文获取类型
收费全文 | 1240篇 |
免费 | 31篇 |
国内免费 | 3篇 |
专业分类
化学 | 787篇 |
晶体学 | 10篇 |
力学 | 21篇 |
数学 | 84篇 |
物理学 | 372篇 |
出版年
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 17篇 |
2017年 | 10篇 |
2016年 | 24篇 |
2015年 | 17篇 |
2014年 | 29篇 |
2013年 | 55篇 |
2012年 | 52篇 |
2011年 | 46篇 |
2010年 | 39篇 |
2009年 | 53篇 |
2008年 | 58篇 |
2007年 | 46篇 |
2006年 | 59篇 |
2005年 | 43篇 |
2004年 | 57篇 |
2003年 | 28篇 |
2002年 | 39篇 |
2001年 | 38篇 |
2000年 | 32篇 |
1999年 | 14篇 |
1998年 | 15篇 |
1997年 | 16篇 |
1996年 | 20篇 |
1995年 | 10篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 17篇 |
1991年 | 15篇 |
1990年 | 19篇 |
1989年 | 19篇 |
1988年 | 19篇 |
1987年 | 20篇 |
1986年 | 36篇 |
1985年 | 26篇 |
1984年 | 26篇 |
1983年 | 9篇 |
1982年 | 13篇 |
1981年 | 19篇 |
1980年 | 13篇 |
1979年 | 22篇 |
1978年 | 23篇 |
1977年 | 15篇 |
1976年 | 15篇 |
1975年 | 20篇 |
1974年 | 11篇 |
1973年 | 10篇 |
1972年 | 7篇 |
排序方式: 共有1274条查询结果,搜索用时 0 毫秒
41.
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
42.
Norimasa Yoza Hisanobu Hirano Yoshinobu Baba Shigeru Ohashi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):605-608
Abstract Inorganic pyrophosphatase (EC 3. 6. 1. 1) drived the reaction of uridine 5′-triphosphate with glucose 1-monophosphate in the direction of uridine 5′-diphosphoglucose formation. 相似文献
43.
Abstract Oligomerization of butadiene with the catalyst system of nickel(II)chloride, electron donor, and lithium aluminum hydride or sodium borohydride has been studied. Most oligomers obtained with this catalyst were linear, and dihydrogenated dimers, trimers, and tetramers. They were n-octa-1,6-diene, n-octa-1,7-diene, n-dodeca-1,6,10-triene, and n-hexadeca-1,6,10,14-tetraene, which were identified by means of infrared, nuclear magnetic resonance, and mass spectrometry. Yields of each oligomer were strongly affected by the nature of the electron donors used. The hydrogen required for the formation of the hydrooligomers was assumed to originate from the lithium aluminum hydride or sodium borohydride used as a reducing agent. A proposed mechanism for the hydrooligomerization is that butadiene is oligomerized on the nickel atom, and the produced oligoolefins, bonded to the nickel by two terminal π-allylic bonds, are dihydrogenated to linear hydrooligomers. 相似文献
44.
The acceleration effect of poly(ethylene oxide) on nucleophilic reactions was investigated. The enhancement of the reaction rate was interpreted by the cooperative solvation of alkali metal ions with ethereal oxygens of PEO resulting in active nucleophilic anions. In relation to the complex formation of alkali metal ions with PEO, the oligo(ethylene oxide) derivatives were prepared as the synthetic ionophores, which were able to transport alkali metal ions selectively through a liquid membrane against the alkali metal ion concentration. 相似文献
45.
Syntheses of cyclic oligomer and polymer were attempted with magnesiacyclohexane as the initiator in HMPA. The oligomer of α-methylstyrene, initiated by magnesiacyclohexane, was treated with dimethyldichlorosilane in order to obtain a stable cyclic oligomer. The products were investigated by GPC, IR, NMR, and elemental analysis. It was found that magnesia-cyclohexane could not be activated enough by HMPA, and that the magnesium-carbon bond was not stable in HMPA, and that the chain transfer reaction might occur repeatedly during the polymerization. Consequently, the yield of cyclic oligomer was so low that cyclic compounds could not be discriminated from the linear oligomer. 相似文献
46.
F. Ditrói F. Tárkányi S. Takács A. Hermanne H. Yamazaki M. Baba A. Mohammadi 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(2):853-865
As a part of our series of studies on charged particle induced reactions on various target materials, proton induced excitation functions on natural cobalt have been determined by using the stacked-foil technique. In these measurements the radionuclides 55,56,57,58Co, 51Cr, 52,54,56Mn and 56,57Ni have been identified. For the above mentioned nuclides the cross-sections were derived from the measured activities and were compared with the literature data and with the results of EMPIRE code calculations and tabulated values in the TENDL 2011 library (based on TALYS code calculations). The agreement with previous measurements and with theoretical values was acceptable. 相似文献
47.
48.
Yamazaki Kazuyoshi Hosaka Makoto Yamada Kenichiro Ogata Takeshi Shimada Kenichi 《Optical Review》2016,23(5):848-858
Optical Review - A precise and fast method for controlling the reference-beam angle of an angular-multiplexed holographic data storage system (HDSS)—to achieve larger capacity and faster... 相似文献
49.
Toshimitsu Yamazaki M.J.A. Yoshinori Akaishi 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2007,83(5):144-150
We have studied the structure of K−pp comprehensively by solving this threebody system in a variational method, starting from the Ansatz that the Λ(1405) resonance (≡Λ*) is a K−p bound state. The structure of K−pp reveals a molecular feature, namely, the K− in Λ* as an “atomic center” plays a key role in producing strong covalent bonding with the other proton. We point out that strongly bound nuclear systems are formed by “super strong” nuclear force due to migrating real bosonic particles a la Heitler-London-Heisenberg, whereas the normal nuclear force is caused by mediating virtual mesons. We have shown that the elementary process, p + p → K+ + Λ* + p, which occurs in a short impact parameter and with a large momentum transfer, leads to unusually large self-trapping of Λ* by the involved proton, since the Λ*-p system exists as a compact doorway state propagating to K−pp. 相似文献
50.
N. Kuroda S. Ulmer D. J. Murtagh S. Van Gorp Y. Nagata M. Diermaier S. Federmann M. Leali C. Malbrunot V. Mascagna O. Massiczek K. Michishio T. Mizutani A. Mohri H. Nagahama M. Ohtsuka B. Radics S. Sakurai C. Sauerzopf K. Suzuki M. Tajima H. A. Torii L. Venturelli B. Wünschek J. Zmeskal N. Zurlo H. Higaki Y. Kanai E. Lodi Rizzini Y. Nagashima Y. Matsuda E. Widmann Y. Yamazaki 《Hyperfine Interactions》2015,235(1-3):13-20
In order to test CPT symmetry between antihydrogen and its counterpart hydrogen, the ASACUSA collaboration plans to perform high precision microwave spectroscopy of ground-state hyperfine splitting of antihydrogen atom in-flight. We have developed an apparatus (“cusp trap”) which consists of a superconducting anti-Helmholtz coil and multiple ring electrodes. For the preparation of slow antiprotons and positrons, Penning-Malmberg type traps were utilized. The spectrometer line was positioned downstream of the cusp trap. At the end of the beamline, an antihydrogen beam detector was located, which comprises an inorganic Bismuth Germanium Oxide (BGO) single-crystal scintillator housed in a vacuum duct and surrounding plastic scintillators. A significant fraction of antihydrogen atoms flowing out the cusp trap were detected. 相似文献