全文获取类型
收费全文 | 85078篇 |
免费 | 1425篇 |
国内免费 | 1105篇 |
专业分类
化学 | 29180篇 |
晶体学 | 842篇 |
力学 | 7171篇 |
综合类 | 30篇 |
数学 | 32767篇 |
物理学 | 17618篇 |
出版年
2023年 | 155篇 |
2022年 | 183篇 |
2021年 | 290篇 |
2020年 | 311篇 |
2019年 | 272篇 |
2018年 | 10592篇 |
2017年 | 10403篇 |
2016年 | 6342篇 |
2015年 | 1144篇 |
2014年 | 676篇 |
2013年 | 807篇 |
2012年 | 4419篇 |
2011年 | 11144篇 |
2010年 | 6092篇 |
2009年 | 6408篇 |
2008年 | 7029篇 |
2007年 | 9119篇 |
2006年 | 640篇 |
2005年 | 1618篇 |
2004年 | 1747篇 |
2003年 | 2143篇 |
2002年 | 1150篇 |
2001年 | 399篇 |
2000年 | 436篇 |
1999年 | 317篇 |
1998年 | 336篇 |
1997年 | 265篇 |
1996年 | 357篇 |
1995年 | 252篇 |
1994年 | 176篇 |
1993年 | 167篇 |
1992年 | 127篇 |
1991年 | 132篇 |
1990年 | 138篇 |
1989年 | 123篇 |
1988年 | 96篇 |
1987年 | 90篇 |
1986年 | 90篇 |
1985年 | 67篇 |
1984年 | 61篇 |
1983年 | 55篇 |
1982年 | 57篇 |
1981年 | 48篇 |
1980年 | 54篇 |
1979年 | 64篇 |
1978年 | 49篇 |
1914年 | 45篇 |
1912年 | 40篇 |
1909年 | 41篇 |
1908年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Zhihong Zhao Bin Wang Rui Tan Wenjing Liu Minghui Zhang 《Magnetic resonance in chemistry : MRC》2022,60(4):427-433
In this study, the transverse relaxation time (T2) of activated carbon (AC) in different relative environment humidity was detected firstly by low-field nuclear magnetic resonance (LFNMR). The pore size (diameter) of AC distributions was calculated by the relationship between T2 and surface relaxation rate (ρ), where ρ was obtained by the detection of nine porous materials with known pore size. The results showed that the pore size distributions of AC calculated by ρ < 0.19 nm/ms were in good agreement with that obtained by nitrogen adsorption method and proved that LFNMR as a new detection method was feasible for characterizing AC pore size distribution. 相似文献
2.
Lin Yu Wu Yeyu Tan Xuecai Wu Jiawen Huang Kejing Mi Yan Ou Panpan Wei Fucun 《Journal of Solid State Electrochemistry》2022,26(4):959-971
Journal of Solid State Electrochemistry - An ultrasensitive “signal-off–on” electrochemiluminescence (ECL) biosensor is constructed based on f1-TiO2/g-C3N4/PDA for thrombin... 相似文献
3.
Tian Xiu-Zhi Yang Rui Ma Jia-Jia Ni Yong-Hao Deng Hai-Bo Dai Lei Tan Jiao-Jun Zhang Mei-Yun Jiang Xue 《高分子科学》2022,40(7):789-798
Chinese Journal of Polymer Science - Antistatic and strength properties are of vital importance for polyurethane rubber used in moving parts of many industrial instruments. Herein, polyurethane was... 相似文献
4.
Li Quanxin Li Zheng He Cheng Sun Huilin Tan Shengheng Zhang Hua 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2105-2115
Journal of Radioanalytical and Nuclear Chemistry - The simplified 8-oxide system (SiO2-B2O3-Na2O-Al2O3-CaO-TiO2-MoO3-La2O3) has been prepared under two types of cooling methods, and analyzed with... 相似文献
5.
In the paper, the authors establish several integral representations for the generating functions of the large and little Schröder numbers and for the large and little Schröder numbers. 相似文献
6.
Mesoscopic modeling at the pore scale offers great promise in exploring the underlying structure transport performance of flow through porous media. The present work studies the fluid flow subjected to capillarity-induced resonance in porous media characterized by different porous structure and wettability. The effects of porosity and wettability on the displacement behavior of the fluid flow through porous media are discussed. The results are presented in the form of temporal evolution of percentage saturation and displacement of the fluid front through porous media. The present study reveals that the vibration in the form of acoustic excitation could be significant in the mobilization of fluid through the porous media. The dependence of displacement of the fluid on physicochemical parameters like wettability of the surface, frequency along with the porosity is analyzed. It was observed that the mean displacement of the fluid is more in the case of invading fluid with wetting phase where the driving force strength is not so dominant. 相似文献
7.
8.
Sarah Peluse 《Israel Journal of Mathematics》2018,227(1):379-396
We prove that the group of diffeomorphisms of the interval [0, 1] contains surface groups whose action on (0, 1) has no global fix point and such that only countably many points of the interval (0, 1) have non-trivial stabiliser. 相似文献
9.
Jie Lu Ju-Kang Wu Yao Jiang Dr. Peng Tan Lin Zhang Yu Lei Prof. Xiao-Qin Liu Prof. Lin-Bing Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(16):6490-6496
Hierarchically porous metal–organic frameworks (HP-MOFs) are promising in various applications. Most reported HP-MOFs are prepared based on the generation of mesopores in microporous frameworks, and the formed mesopores are connected by microporous channels, limiting the accessibility of mesopores for bulky molecules. A hierarchical structure is formed by constructing microporous MOFs in uninterrupted mesoporous tunnels. Using the confined space in as-prepared mesoporous silica, highly dispersed metal precursors for MOFs are coated on the internal surface of mesoporous tunnels. Ligand vapor-induced crystallization is employed to enable quantitative formation of MOFs in situ, in which sublimated ligands diffuse into mesoporous tunnels and react with metal precursors. The obtained hierarchically porous composites exhibit record-high adsorption capacity for the bulky molecule trypsin. The thermal and storage stability of trypsin is improved upon immobilization on the composites. 相似文献
10.