全文获取类型
收费全文 | 21306篇 |
免费 | 3948篇 |
国内免费 | 3282篇 |
专业分类
化学 | 16030篇 |
晶体学 | 315篇 |
力学 | 1338篇 |
综合类 | 259篇 |
数学 | 2403篇 |
物理学 | 8191篇 |
出版年
2024年 | 22篇 |
2023年 | 376篇 |
2022年 | 481篇 |
2021年 | 688篇 |
2020年 | 822篇 |
2019年 | 861篇 |
2018年 | 714篇 |
2017年 | 638篇 |
2016年 | 1121篇 |
2015年 | 1073篇 |
2014年 | 1312篇 |
2013年 | 1570篇 |
2012年 | 1880篇 |
2011年 | 1962篇 |
2010年 | 1537篇 |
2009年 | 1482篇 |
2008年 | 1601篇 |
2007年 | 1380篇 |
2006年 | 1327篇 |
2005年 | 1117篇 |
2004年 | 876篇 |
2003年 | 715篇 |
2002年 | 871篇 |
2001年 | 674篇 |
2000年 | 576篇 |
1999年 | 430篇 |
1998年 | 329篇 |
1997年 | 311篇 |
1996年 | 291篇 |
1995年 | 249篇 |
1994年 | 217篇 |
1993年 | 180篇 |
1992年 | 131篇 |
1991年 | 122篇 |
1990年 | 101篇 |
1989年 | 89篇 |
1988年 | 73篇 |
1987年 | 47篇 |
1986年 | 57篇 |
1985年 | 46篇 |
1984年 | 27篇 |
1983年 | 26篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1975年 | 8篇 |
1972年 | 8篇 |
1965年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
1.
Liu Wenbin Huang Yiwei Huang Guolin Fan Lijiao Xie Yuming Shi Jeffery 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2055-2068
Journal of Radioanalytical and Nuclear Chemistry - Eco-friendly and low-cost composite, amidoxime-functionalized microcrystalline cellulose/mesoporous silica (MCC/MS-AO), were synthesized by... 相似文献
2.
Qianqian Fan Zirui Liu Feng Qiu Prof. Yong Mao Prof. Qingju Liu Prof. Longzhou Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(63):e202202700
The artificially accurate design of nonmetal electrocatalysts’ active site has been a huge challenge because no pure active species with the specific structure could be strictly controlled by traditional synthetic methods. Species with a multiconfiguration in the catalyst hinder identification of the active site and the subsequent comprehension of the reaction mechanism. We have developed a novel electro-assisted molecular assembly strategy to obtain a pure pentagon ring on perfect graphene avoiding other reconstructed structures. More importantly, the active atom was confirmed by the subtle passivation process as the topmost carbon atom. Recognition of the carbon-defect electrocatalysis reaction mechanism was first downsized to the single-atom scale from the experimental perspective. It is expected that this innovative electro-assisted molecular assembly strategy could be extensively applied in the active structure-controlled synthesis of nonmetal electrocatalysts and verification of the exact active atom. 相似文献
3.
High Energy Chemistry - Modification of Polyvinylidene fluoride (PVDF) by radiation grafting is a research hotspot in recent years. In this study, the monomer 2-Hydroxyethyl methacrylate (HEMA) was... 相似文献
4.
Liu Jun-Wei Shen Shu-Qian Li Ming Li Lei 《International Journal of Theoretical Physics》2021,60(5):1712-1719
International Journal of Theoretical Physics - Quantum coherence, coming from quantum superposition, occupies a significant position in the field of physics. We put forward a lower bound of the... 相似文献
5.
Journal of Algebraic Combinatorics - A dessin is called circular if the boundary of each face is a circuit (a simple cycle). In this paper, we address the problem of characterizing edge-transitive... 相似文献
6.
Nonlinear Dynamics - Epilepsy is the second largest neurological disease which seriously threatens human life and health. The one important reason of inducing epileptic seizures is ischemic stroke... 相似文献
7.
以六水氯化镁和六次甲基四胺为原料,采用水热法合成四方体MgO,考察其对有机染料甲基橙和亚甲基蓝的吸附行为.通过TGA-DTA、SEM、XRD、N2-sorption和FT-IR等手段表征样品.结果表明,原料浓度、温度和表面活性剂对四方体MgO结构的形成影响较小,而反应时间的延长有助于有序结构的组装.温度170℃、时间24h、MgCl2·6H2O与C6H12N4浓度比为1∶2和表面活性剂PVP是制备四方体MgO的最佳条件.在溶液浓度10mg · L-1的单一吸附实验过程中,四方体MgO对甲基橙和亚甲基蓝的去除率分别为91.3;和22.3;,吸附过程均为单层吸附且符合Langmuir等温吸附模型和伪二级吸附动力学方程.在溶液浓度40 mg·L-1、甲基橙和亚甲基蓝浓度比3∶1的混合溶液吸附过程中,四方体MgO对甲基橙和亚甲基蓝的去除率分别为80.1;和97.9;. 相似文献
8.
9.
Richiro Ushimaru Zhang Chen Houyuan Zhao Po-hsun Fan Prof. Dr. Hung-wen Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(9):3586-3590
Albomycin δ2 is a sulfur-containing sideromycin natural product that shows potent antibacterial activity against clinically important pathogens. The l -serine-thioheptose dipeptide partial structure, known as SB-217452, has been found to be the active seryl-tRNA synthetase inhibitor component of albomycin δ2. Herein, it is demonstrated that AbmF catalyzes condensation between the 6′-amino-4′-thionucleoside with the d -ribo configuration and seryl-adenylate supplied by the serine adenylation activity of AbmK. Formation of the dipeptide is followed by C3′-epimerization to produce SB-217452 with the d -xylo configuration, which is catalyzed by the radical S-adenosyl-l -methionine enzyme AbmJ. Gene deletion suggests that AbmC is involved in peptide assembly linking SB-217452 with the siderophore moiety. This study establishes how the albomycin biosynthetic machinery generates its antimicrobial component SB-217452. 相似文献
10.
Wang Dong Ming Fei Song Xue-Ke Ye Liu Chen Jing-Ling 《The European Physical Journal C - Particles and Fields》2020,80(8):1-16
The European Physical Journal C - We study the isentropic evolution of the matter produced in relativistic heavy-ion collisions for various values of the entropy-per-baryon ratio of interest for... 相似文献