全文获取类型
收费全文 | 3744篇 |
免费 | 92篇 |
国内免费 | 22篇 |
专业分类
化学 | 3142篇 |
晶体学 | 41篇 |
力学 | 44篇 |
数学 | 166篇 |
物理学 | 465篇 |
出版年
2023年 | 24篇 |
2022年 | 33篇 |
2021年 | 43篇 |
2020年 | 56篇 |
2019年 | 50篇 |
2018年 | 30篇 |
2017年 | 30篇 |
2016年 | 66篇 |
2015年 | 75篇 |
2014年 | 88篇 |
2013年 | 189篇 |
2012年 | 211篇 |
2011年 | 271篇 |
2010年 | 139篇 |
2009年 | 144篇 |
2008年 | 295篇 |
2007年 | 228篇 |
2006年 | 279篇 |
2005年 | 250篇 |
2004年 | 219篇 |
2003年 | 197篇 |
2002年 | 188篇 |
2001年 | 47篇 |
2000年 | 61篇 |
1999年 | 48篇 |
1998年 | 33篇 |
1997年 | 36篇 |
1996年 | 40篇 |
1995年 | 36篇 |
1994年 | 33篇 |
1993年 | 31篇 |
1992年 | 29篇 |
1991年 | 21篇 |
1990年 | 20篇 |
1989年 | 13篇 |
1988年 | 17篇 |
1987年 | 17篇 |
1986年 | 12篇 |
1985年 | 28篇 |
1984年 | 32篇 |
1983年 | 12篇 |
1982年 | 25篇 |
1981年 | 26篇 |
1980年 | 25篇 |
1979年 | 14篇 |
1978年 | 17篇 |
1976年 | 10篇 |
1975年 | 15篇 |
1974年 | 10篇 |
1973年 | 9篇 |
排序方式: 共有3858条查询结果,搜索用时 0 毫秒
31.
32.
33.
Hiroyuki Nishide Takayuki Suzuki Yuji Soejima Eishun Tsuchida 《Macromolecular Symposia》1994,80(1):145-156
Facilitated or complexation-mediated transport of oxygen in the solid membrane containing a fixed carrier was described, by using the polymer-bound cobalt Schiff's base chelate (CoS) and cobaltporphyrin (CoP). α3 β-Substituted cobaltporphyrin derivatives were synthesized: The oxygen-binding reaction to cobalt was affected by the cavity structure on porphyrin, i.e., unbulky amido-substituted groups such as acetylamido- and acrylamido-substituents enhanced oxygen-binding and -dissociation rate constant or provided an oxygen-binding pathway. Oxygen transport through the membranes of these polymer-bound CoP derivatives was selectively augmented due to the rapid and reversible oxygen-binding. Diffusion constants via the fixed CoPs correlated to the characteristics of oxygen-binding reaction. 相似文献
34.
35.
Toshihiro Okajima Hiroyuki Setoyama Marek Brancewicz Masahide Kawamoto Yoshiharu Sakurai 《X射线光谱测定》2020,49(3):390-397
X-ray fluorescence spectra of copper (Cu) metal, copper monoxide (CuO), and potassium chromate (K2CrO4) were recorded as a function of incident X-ray energy near the Cu K-edge and chromium (Cr) K-edge, respectively, using a conventional silicon drift detector. The spectra contained components due to elastic, inelastic, and multiple scattering, in addition to the Kα and Kβ lines. Cu and Cr K-edge X-ray absorption fine structure (XAFS) spectra of Cu, CuO, and K2CrO4 were obtained by an intensity analysis of the Kα and Kβ lines. The intensity of the Kβ line for the different incident photon energies was obtained by numerically removing the additional scattering components using the MUSCAT program. These spectra exhibited a jump near the K absorption edges, which reproduced the spectral features obtained in transmission mode for both Cu, CuO, and K2CrO4. A chemical shift was also clearly identified in the X-ray absorption near edges structure using the X-ray fluorescence Kβ line. In addition, the Cr K-edge extended XAFS spectrum of K2CrO4 was clearly observed using the Cr Kβ fluorescent line. The XAFS measurements on the Kα and Kβ lines are possible, and they carry equally valuable information. 相似文献
36.
The oxidative polymerization provides a new synthetic route to polyaromatics. Poly(p-phenylene sulfide) (PPS) is produced by oxidative polymerization of thiophenol with a vanadyl complex catalyst. The metal complexes act as an efficient catalyst of oxygen oxidative polymerization. The polymerization to yield PPS is discussed especially focusing on the catalytic mechanism of the complexes. 相似文献
37.
38.
39.
40.
Takaaki Kakitsuka Shinji Matsuo Seok–Hwan Jeong Toru Segawa Hiroshi Okamoto Yoshihiro Kawaguchi Yasuhiro Kondo Yuzo Yoshikuni Hiroyuki Suzuki 《Optical and Quantum Electronics》2006,38(12-14):1053-1060
We theoretically investigated a digitally tunable laser with a chirped ladder filter and a ring resonator to obtain a wide wavelength tuning range covering the whole C- or L- band. The clear relation between the tuning range and laser structure, especially the ladder filter, is described analytically. The introduction of a chirped structure into a ladder filter is effective in achieving both wide tunability and a stable lasing mode. A numerical simulation based on multimode rate equations shows that a tuning range of over 40 nm and a mode suppression ratio over 40 dB can be achieved by introducing a chirped ladder filter. 相似文献