全文获取类型
收费全文 | 441605篇 |
免费 | 5804篇 |
国内免费 | 1261篇 |
专业分类
化学 | 238695篇 |
晶体学 | 6535篇 |
力学 | 18855篇 |
综合类 | 13篇 |
数学 | 50817篇 |
物理学 | 133755篇 |
出版年
2021年 | 4127篇 |
2020年 | 4374篇 |
2019年 | 4711篇 |
2018年 | 6019篇 |
2017年 | 5893篇 |
2016年 | 9118篇 |
2015年 | 5771篇 |
2014年 | 8821篇 |
2013年 | 20613篇 |
2012年 | 16116篇 |
2011年 | 19761篇 |
2010年 | 13838篇 |
2009年 | 13614篇 |
2008年 | 18058篇 |
2007年 | 17929篇 |
2006年 | 16628篇 |
2005年 | 14830篇 |
2004年 | 13769篇 |
2003年 | 12073篇 |
2002年 | 11890篇 |
2001年 | 13513篇 |
2000年 | 10145篇 |
1999年 | 7961篇 |
1998年 | 6616篇 |
1997年 | 6351篇 |
1996年 | 6129篇 |
1995年 | 5506篇 |
1994年 | 5423篇 |
1993年 | 5229篇 |
1992年 | 5857篇 |
1991年 | 5952篇 |
1990年 | 5685篇 |
1989年 | 5499篇 |
1988年 | 5511篇 |
1987年 | 5394篇 |
1986年 | 5118篇 |
1985年 | 6600篇 |
1984年 | 6717篇 |
1983年 | 5315篇 |
1982年 | 5414篇 |
1981年 | 5386篇 |
1980年 | 4975篇 |
1979年 | 5363篇 |
1978年 | 5496篇 |
1977年 | 5394篇 |
1976年 | 5337篇 |
1975年 | 4914篇 |
1974年 | 4888篇 |
1973年 | 4884篇 |
1972年 | 3456篇 |
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
91.
Farsi R. Mohammadi M. K. Saghanezhad S. J. 《Russian Journal of Organic Chemistry》2021,57(12):2002-2009
Russian Journal of Organic Chemistry - Herein, we report the sulfonamide-functionalized covalent organic framework (COF-SO3H), prepared by condensation of melamine and terephthalaldehyde and... 相似文献
92.
93.
94.
Mathieu Boiret Anna de Juan Nathalie Gorretta Yves-Michel Ginot Jean-Michel Roger 《Analytica chimica acta》2015
Raman chemical imaging provides chemical and spatial information about pharmaceutical drug product. By using resolution methods on acquired spectra, the objective is to calculate pure spectra and distribution maps of image compounds. With multivariate curve resolution-alternating least squares, constraints are used to improve the performance of the resolution and to decrease the ambiguity linked to the final solution. Non negativity and spatial local rank constraints have been identified as the most powerful constraints to be used. 相似文献
95.
96.
Vsevolod Khikhlovskyi Albert J. J. M. van Breemen Jasper J. Michels René A. J. Janssen Gerwin H. Gelinck Martijn Kemerink 《Journal of Polymer Science.Polymer Physics》2015,53(17):1231-1237
In many organic electronic devices functionality is achieved by blending two or more materials, typically polymers or molecules, with distinctly different optical or electrical properties in a single film. The local scale morphology of such blends is vital for the device performance. Here, a simple approach to study the full 3D morphology of phase‐separated blends, taking advantage of the possibility to selectively dissolve the different components is introduced. This method is applied in combination with AFM to investigate a blend of a semiconducting and ferroelectric polymer typically used as active layer in organic ferroelectric resistive switches. It is found that the blend consists of a ferroelectric matrix with three types of embedded semiconductor domains and a thin wetting layer at the bottom electrode. Statistical analysis of the obtained images excludes the presence of a fourth type of domains. The criteria for the applicability of the presented technique are discussed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1231–1237 相似文献
97.
Mariia Svyntkivska Tomasz Makowski Ewa Piorkowska Marek Brzezinski Agata Herc Anna Kowalewska 《Molecules (Basel, Switzerland)》2021,26(5)
Electrospun nonwovens of poly(L-lactide) (PLLA) modified with multiwall carbon nanotubes (MWCNT) and linear ladder-like poly(silsesquioxane) with methoxycarbonyl side groups (LPSQ-COOMe) were obtained. MWCNT and LPSQ-COOMe were added to the polymer solution before the electrospinning. In addition, nonwovens of PLLA grafted to modified MWCNT were electrospun. All modified nonwovens exhibited higher tensile strength than the neat PLA nonwoven. The addition of 10 wt.% of LPSQ-COOMe and 0.1 wt.% of MWCNT to PLLA increased the tensile strength of the nonwovens 2.4 times, improving also the elongation at the maximum stress. 相似文献
98.
Rajkumar P. Diwakar K. Subadevi R. Gnanamuthu R. M. Wang Fu-Ming Liu Wei-Ren Sivakumar M. 《Journal of Solid State Electrochemistry》2021,25(3):939-948
Journal of Solid State Electrochemistry - The “shuttle effect” of polysulfides is a serious issue, resulting in a decrease in the life-cycle of lithium-sulfur (Li-S) batteries. To... 相似文献
99.
Russian Journal of Organic Chemistry - A green protocol has been developed for the preparation of 2,2′-(arylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones) following the... 相似文献
100.