全文获取类型
收费全文 | 14685篇 |
免费 | 2461篇 |
国内免费 | 1483篇 |
专业分类
化学 | 10636篇 |
晶体学 | 106篇 |
力学 | 845篇 |
综合类 | 62篇 |
数学 | 1827篇 |
物理学 | 5153篇 |
出版年
2023年 | 344篇 |
2022年 | 326篇 |
2021年 | 503篇 |
2020年 | 728篇 |
2019年 | 615篇 |
2018年 | 546篇 |
2017年 | 447篇 |
2016年 | 676篇 |
2015年 | 674篇 |
2014年 | 861篇 |
2013年 | 1056篇 |
2012年 | 1347篇 |
2011年 | 1431篇 |
2010年 | 950篇 |
2009年 | 831篇 |
2008年 | 899篇 |
2007年 | 822篇 |
2006年 | 809篇 |
2005年 | 617篇 |
2004年 | 474篇 |
2003年 | 382篇 |
2002年 | 382篇 |
2001年 | 282篇 |
2000年 | 269篇 |
1999年 | 301篇 |
1998年 | 224篇 |
1997年 | 210篇 |
1996年 | 250篇 |
1995年 | 209篇 |
1994年 | 166篇 |
1993年 | 125篇 |
1992年 | 132篇 |
1991年 | 110篇 |
1990年 | 120篇 |
1989年 | 95篇 |
1988年 | 70篇 |
1987年 | 46篇 |
1986年 | 49篇 |
1985年 | 39篇 |
1984年 | 28篇 |
1983年 | 19篇 |
1982年 | 16篇 |
1981年 | 16篇 |
1980年 | 9篇 |
1979年 | 20篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1975年 | 13篇 |
1973年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
Xianghao Luo Anqi Tian Mengyu Pei Dr. Jiaying Yan Dr. Xiang Liu Prof. Long Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(3):e202103361
With the development of green chemistry, it is still a challenge to maintain the unstable valence state of the metal in heterogeneous catalysts and realize new catalytic synthesis methods. In this paper, it is reported that an univalent copper nanocomposite (Cu@Al/SBA-15) can efficiently catalyze the formation of novel amino-containing benzotriazoles with great fluorescence properties in a new synthetic strategy. Subsequently, its application is further verified by an acylation reaction to produce a series of novel benzotriazoles derivatives with high yield. It is worth noting that the Cu@Al/SBA-15 nanocomposites not only enable the reaction completed with high yield in a short time, but can also be recycled many times without a significant reduction in activity, and the leaching of copper and aluminum species in reaction system is negligible. Finally, the detailed and feasible reaction mechanism is also provided. 相似文献
3.
Huo Guang-Hua Cui Chao-Yu He Tian Yan Jun-Qing Peng Wen-Wen 《Chemistry of Natural Compounds》2022,58(3):468-470
Chemistry of Natural Compounds - A new carotane sesquiterpenoid, methyl gymnabloate (1), was isolated from the fermentation broth of the wild macrofungus Gymnopus sp. 0612-9. Its structure was... 相似文献
4.
Dang Huyen Vu Xuan Dang Hanh Vu Bich Doan Huu Dung Nguyen Tan Phong 《Research on Chemical Intermediates》2022,48(3):1311-1311
Research on Chemical Intermediates - 相似文献
5.
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
6.
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
7.
Tian Jie Yang Weifeng Chen Min Zheng Minfang Chen Ding Qiu Yusheng 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(2):1039-1049
Journal of Radioanalytical and Nuclear Chemistry - This study presents a time-efficient method of analysing 210Pb, 210Bi, and 210Po in natural waters. The optimum pH (1.00), temperature... 相似文献
8.
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
9.
The separation efficiency of charge carriers determines the analytical sensitivity of the paper-based photoelectrochemical sensor. Herein, the Lewis base modification strategy is proposed to promote the carrier separation through an in-situ ion exchange method. Firstly, three-dimensional paper-based hierarchically TiO2 (PHT) arrays are prepared with the one-step hydrothermal method. With the aid of Lewis base, the photo-induced charge separation efficiency and the photocurrent signal are obviously increased. Ultimately, sensitive sensing of prostate specific antigen (PSA) is achieved and the linear range is 1 pg/mL–100 ng/mL with the detection limitation of 0.3 pg/mL. 相似文献
10.
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