全文获取类型
收费全文 | 5078篇 |
免费 | 246篇 |
国内免费 | 28篇 |
专业分类
化学 | 3904篇 |
晶体学 | 46篇 |
力学 | 71篇 |
数学 | 400篇 |
物理学 | 931篇 |
出版年
2023年 | 32篇 |
2022年 | 56篇 |
2021年 | 109篇 |
2020年 | 88篇 |
2019年 | 95篇 |
2018年 | 74篇 |
2017年 | 71篇 |
2016年 | 177篇 |
2015年 | 143篇 |
2014年 | 178篇 |
2013年 | 314篇 |
2012年 | 360篇 |
2011年 | 441篇 |
2010年 | 255篇 |
2009年 | 249篇 |
2008年 | 354篇 |
2007年 | 289篇 |
2006年 | 294篇 |
2005年 | 227篇 |
2004年 | 205篇 |
2003年 | 178篇 |
2002年 | 212篇 |
2001年 | 102篇 |
2000年 | 106篇 |
1999年 | 61篇 |
1998年 | 39篇 |
1997年 | 51篇 |
1996年 | 46篇 |
1995年 | 35篇 |
1994年 | 27篇 |
1993年 | 32篇 |
1992年 | 39篇 |
1991年 | 23篇 |
1990年 | 31篇 |
1989年 | 31篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 14篇 |
1985年 | 27篇 |
1984年 | 23篇 |
1983年 | 16篇 |
1982年 | 18篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 10篇 |
1978年 | 15篇 |
1977年 | 19篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1970年 | 17篇 |
排序方式: 共有5352条查询结果,搜索用时 93 毫秒
21.
22.
The concept of crystallization dynamics method evaluating the miscibility of binary blend system including crystalline component
was proposed. Three characteristic rates, nucleation, crystal growth rates (N*, G*) and growth rate of conformation (G
c*) were used to evaluate the miscibility of PVDF/at-PMMA and PVDF/iso-PMMA by the simultaneous DSC-FTIR. N*, G* and G
c* depended remarkably on both temperature and blend fraction (ϕPMMA) for PVDF/at-PMMA system, which indicated the miscible system. PVDF/iso-PMMA showed small ϕPMMA dependency of N*, G* and G
c*, was estimated the immiscible system. The ΔT/T
m0 values, corresponding to Gibbs energy required to attend the constant G* and G
c*, evaluated from G* and G
c* showed the good linear relationships with different slope. The experimental results suggested that the concentration fluctuation
existed in PVDF/iso-PMMA system. 相似文献
23.
Nak-Jin Seong Young-Hun Jo Myung-Hwa Jung Soon-Gil Yoon 《Journal of magnetism and magnetic materials》2006
Epitaxial Ti0.97Co0.03O2:Sb0.01(TCO:Sb) films were deposited on R-Al2O3 (1 1 0 2) substrates at 500 °C in various deposition pressures by pulsed laser deposition. The solubility of cobalt within the films increases with decreasing deposition pressure at a deposition temperature of 500 °C. The TCO:Sb films deposited at 5×10−6 Torr exhibit a p-type anomalous Hall effect having a hole concentration of 6.1×1022/cm3 at 300 K. On the other hand, films deposited at 4×10−4 Torr exhibits an n-type anomalous Hall effect having an electron concentration of about 1.1×1021/cm3. p- or n-type DMS characteristics depends on the change of the structure of TCO:Sb films and the solubility of Co is possible by controlling the deposition pressure. 相似文献
24.
The evaluation of a badge-type diffusive sampler for measuring formaldehyde using 3-methyl-2-benzothiazolinone hydrazone (MBTH) was investigated. On average, the formaldehyde concentration in blanks was reduced by approximately 31% by cleaning procedures. The cleaning techniques did not significantly differ in effectiveness. The maximum sampling rate was 22.4 +/- 3.5 mL min(-1) at MBTH concentrations of 0.05%. The formaldehyde concentration in blanks did not appreciably increase over a period of about 1 month at room temperature, and was 0.36 +/- 0.03 microg, with a relative standard deviation of 8%. The diffusive sampler had good precision and accuracy for measuring formaldehyde in indoor environments. For a 24-h exposure time, the limits of detection and quantification calculated with the field blanks were 9.7 and 13.8 ppb, respectively. The minimum exposure times were calculated based on the measured and calculated limits of quantification, the sampling rate, and the atmospheric formaldehyde concentration. The capacity of the diffusive sampler with 0.5% MBTH was 3 ppm h(-1), approximately 1.5-times the capacity when the MBTH concentrations were 0.05%. 相似文献
25.
26.
27.
28.
Soderstrom E McKenna JA Abrams GS Adolphsen CE Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D Bonvicini G Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drewer DC Elia R Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G Grosse-Wiesmann P Hanson G Harr R 《Physical review letters》1990,64(25):2980-2983
29.
Komamiya S Abrams GS Adolphsen CE Averill D Ballam J Barish BC Barklow T Barnett BA Bartelt J Bethke S Blockus D Bonvicini G Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan DE Dorfan JM Drewer DC Elia R Feldman GJ Fernandes D Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gatto C Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Grindhammer G Grosse-Wiesmann P Hanson G Harr R 《Physical review letters》1990,64(24):2881-2884
30.