全文获取类型
收费全文 | 400篇 |
免费 | 23篇 |
国内免费 | 50篇 |
专业分类
化学 | 358篇 |
晶体学 | 4篇 |
力学 | 9篇 |
综合类 | 1篇 |
数学 | 10篇 |
物理学 | 91篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 12篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 22篇 |
2011年 | 21篇 |
2010年 | 7篇 |
2009年 | 24篇 |
2008年 | 27篇 |
2007年 | 49篇 |
2006年 | 27篇 |
2005年 | 29篇 |
2004年 | 22篇 |
2003年 | 16篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 8篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1957年 | 1篇 |
排序方式: 共有473条查询结果,搜索用时 15 毫秒
1.
The Effect of Metal‐Ligand Affinity on Fe3O4_Supported Co–Rh Catalysts for Dicyclopentadiene Hydroformylation 下载免费PDF全文
Yubo Ma Shaojun Qing Nana Li Letao Zhang Shouzhu Li Zhixian Gao Hongyi Li Wumanjiang Eli Tianfu Wang 《国际化学动力学杂志》2015,47(10):621-628
The catalytic performances of Co‐Rh/Fe3O4 catalysts modified with phosphine ligands (PPh3) and its analogues on dicyclopentadiene hydroformylation were evaluated. Among these catalysts, Co‐Rh/Fe3O4 modified with tris(p‐trifluoromethylphenyl)phosphine was determined to be effective for monoformyltricyclodecanes production, whereas Co‐Rh/Fe3O4 modified with PPh3 or tri‐p‐tolylphosphine was effective for the diformyltricyclodecanes production. To investigate the ligand effects, the complex catalyst system (Co‐Rh/Fe3O4 and phosphine ligand) was subjected to pretreatment with syngas and then characterized by thermogravimetry and differential thermal analysis (TG‐DTA). It was determined that the threshold decomposition temperature reflected the corresponding Rh‐phosphine interaction strength, affecting the catalytic selectivity toward different products. A weak Rh‐phosphine interaction was desirable to produce monoformyltricyclodecanes with fast reaction kinetics, whereas a strong Rh‐phosphine complex was required for the synthesis of diformyltricyclodecanes. In addition to the selectivity rule shown in the PPh3 series, experiments with other ligands also demonstrated similar selectivity trends. 相似文献
2.
Yingjun Sun Dr. Yingjie Li Yingnan Qin Prof. Lei Wang Prof. Shaojun Guo 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(18):4032-4038
Searching for new anti-poisoning Pt-based catalysts with enhanced activity for alcohol oxidation is the key in direct alcohol fuel cells (DAFCs). However, in the traditional strategy for designing bimetallic or multimetallic alloy is still difficult to achieve a satisfactory heterogeneous electrocatalyst because the activity often depends on only the surface atoms. Herein, we fabricate the multicomponent active sites by creating a sulfide structure on 1D PtNiCo trimetallic nanowires (NWs), to give a PtNiCo/NiCoS interface NWs (IFNWs). Owing to the presence of sulfide interfaces, the PtNiCo/NiCoS IFNWs enable an impressive methanol/ethanol oxidation reaction (MOR/EOR) performance and excellent anti-CO poisoning tolerance. They have the MOR and EOR mass activities of 2.25 Amg-1Pt and 1.62 Amg-1Pt, around 1.26, 3.21 and 1.46, 2.96 times higher than those of PtNiCo NWs and commercial Pt/C, respectively. CO-stripping and XPS measurements further demonstrate that the new interfacial structure and optimal bonding of Pt−CO can result in accelerating the removal of surface adsorbed carbonaceous intermediates. Moreover, such a unique structure has also demonstrated a much-improved ability for the electrochemical detection of some important molecules (H2O2 and NH2NH2). 相似文献
3.
4.
Nanozymes are nanomaterials with enzyme-like catalytic activities. The unique features of nanozymes (such as high stability, low cost, large surface area for bioconjugation, ease of storage, and multi-functionalities) offer unprecedented opportunities for designing electrochemical biosensors. Recent years have witnessed the rapid development of nanozyme-based electrochemical biosensors. To highlight these achievements, this review first discusses the representative nanozymes including peroxidase mimics, oxidase mimics, hydrolase mimics, and superoxide dismutase mimics used in electrochemical biosensors. Then, it summarizes the bioanalytical applications for the detection of various analytes. Finally, current challenges and future research directions are summarized. 相似文献
5.
In situ synthesis of CdS/ZnS composite nanoparticles from ZIF-8 for visible light disposal of Cr(VI)
Bai Lei Ge Lili Gu Junjiu Fang Lu Li Shaojun 《Journal of Sol-Gel Science and Technology》2021,99(1):211-219
Journal of Sol-Gel Science and Technology - Zeolitic Imidazolate Framework (ZIF-8) micropolyhedra were employed as a raw material for the synthesis of fine cadmium sulfide/zinc sulfide (CdS/ZnS)... 相似文献
6.
7.
Shaojun Yang Qiao Tang Long Chen Jin Chang Tian Jiang Jingyi Zhao Prof. Ming Wang Prof. Peng R. Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(41):18243-18250
The abundance of bacterial effectors have inspired us to explore their potential in rewiring malignant cell signaling. Their incapability for entering cells, however, hinders such application. Herein we developed a cationic lipid-based high throughput library screening platform for effective intracellular delivery of bacterial effectors. As the misregulated MAPK signaling is a hallmark of many types of cancer, we turned to the Shigella effector OspF which irreversibly inactivates ERK, the terminal component of MAPK cascade. We created a function-based screening assay to obtain AMPA-O16B lipid nanoparticles for effective OspF intracellular delivery, which inhibited the malignant MAPK signaling and tumor growth in vitro and in vivo. Furthermore, the optimized lipid nanoparticle formulation can deliver OspF to modulate the immunosuppressive responses in macrophages. Our work is a general strategy to explore the therapeutic potentials of naturally evolved bacterial effectors. 相似文献
8.
Shaojun Guo 《物理化学学报》2020,36(7):2001012-0
正发展电解水制氢和金属-空气电池等电化学能源转化与存储技术对于解决日益严峻的能源短缺和环境污染问题具有重要意义~1。氧气析出反应(OER)是电解水制氢和金属-空气电池的关键半反应,但其缓慢的动力学过程却限制了上述能源技术的快速发展~(2,3)。钌/铱基催化剂是当前最为有效 相似文献
9.
Menggang Li Zhonghong Xia Yarong Huang Lu Tao Yuguang Chao Kun Yin Wenxiu Yang Weiwei Yang Yongsheng Yu Shaojun Guo 《物理化学学报》2020,36(9):1912049-0
Direct methanol fuel cells (DMFCs), as one of the important energy conversion devices, are of great interest in the fields of energy, catalysis and materials. However, the application of DMFCs is presently challenged because of the limited activity and durability of cathode catalysts as well as the poisoning issues caused by methanol permeation to the cathode during operation. Herein, we report a new class of Rh-doped PdCu nanoparticles (NPs) with ordered intermetallic structure for enhancing the activity and durability of the cathode for oxygen reduction reaction (ORR) and achieving superior methanol tolerance. The disordered Rh-doped PdCu NPs can be prepared via a simple wet-chemical method, followed by annealing to convert it to ordered phases. The results of transmission electron microscopy (TEM), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), power X-ray diffraction (PXRD) analysis and high resolution TEM (HRTEM) successfully demonstrate the formation of near-spherical NPs with an average size of 6.5 ± 0.5 nm and the conversion of the phase structure. The complete phase transition temperatures of Rh-doped PdCu NPs and PdCu are 500 and 400 ℃, respectively. The molar ratio of Rh/Pd/Cu in the as-synthesized Rh-doped PdCu NPs is 5/48/47. Benefitting from Rh doping and the presence of the ordered intermetallic structure, the Rh-doped PdCu intermetallic electrocatalyst achieves the maximum ORR mass activity of 0.96 A·mg-1 at 0.9 V versus reversible hydrogen electrode (RHE) under alkaline conditions—a 7.4-fold enhancement compared to the commercial Pt/C catalyst. For different electrocatalysts, the ORR activities follow the sequence, ordered Rh-doped PdCu intermetallics > ordered PdCu intermetallics > disordered Rh-doped PdCu NPs > disordered PdCu NPs > commercial Pt/C catalyst. In addition, the distinct structure endows the Rh-doped PdCu intermetallics with highly stable ORR durability with unaltered half-wave potential (E1/2) and mass activity after continuous 20000 cycles, which are higher than those of other electrocatalysts. Furthermore, the E1/2 of the Rh-doped PdCu intermetallics decreases by only 5 mV after adding 0.5 mol·L-1 methanol to the electrolyte, while the commercial Pt/C catalyst negatively shifts by 235 mV and a distinct oxidation peak can be observed. The results indicate that the ORR activity of the Rh-doped PdCu intermetallic electrocatalyst can be well maintained even in the presence of poisoning environment. Our results have demonstrated that Rh-doped PdCu NPs with ordered intermetallic structures is a potential electrocatalyst toward the next-generation high-performance DMFCs. 相似文献
10.
Yunqin Zhang Zixi Chen Yingying Huang Shaojun He Xingkuan Yang Zhibing Wu Xiufang Wang Guozhi Xiao 《Angewandte Chemie (International ed. in English)》2020,59(19):7576-7584
The synthesis of long, branched, and complex carbohydrate sequences remains a challenging task in chemical synthesis. Reported here is an efficient and modular one‐pot synthesis of a nona‐decasaccharide and shorter sequences from Psidium guajava polysaccharides, which have the potent α‐glucosidase inhibitory activity. The synthetic strategy features: 1) several one‐pot glycosylation reactions on the basis of N‐phenyltrifluoroacetimidate (PTFAI) and Yu glycosylation to streamline the chemical synthesis of oligosaccharides, 2) the successful and efficient assembly sequences (first O3′, second O5′, final O2′) toward the challenging 2,3,5‐branched Araf motif, 3) the stereoselective 1,2‐cis‐glucosylation by reagent control, and 4) the convergent [6+6+7] one‐pot coupling reaction for the final assembly of the target nona‐decasaccharide. This orthogonal one‐pot glycosylation strategy can streamline the chemical synthesis of long, branched, and complicated carbohydrate chains. 相似文献