全文获取类型
收费全文 | 1166篇 |
免费 | 59篇 |
国内免费 | 25篇 |
专业分类
化学 | 984篇 |
晶体学 | 8篇 |
力学 | 14篇 |
数学 | 90篇 |
物理学 | 154篇 |
出版年
2024年 | 1篇 |
2023年 | 13篇 |
2022年 | 46篇 |
2021年 | 49篇 |
2020年 | 77篇 |
2019年 | 75篇 |
2018年 | 107篇 |
2017年 | 76篇 |
2016年 | 80篇 |
2015年 | 57篇 |
2014年 | 90篇 |
2013年 | 120篇 |
2012年 | 98篇 |
2011年 | 77篇 |
2010年 | 55篇 |
2009年 | 45篇 |
2008年 | 57篇 |
2007年 | 43篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1990年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有1250条查询结果,搜索用时 0 毫秒
41.
Ali Pourjavadi Maryam Tavakolizadeh Seyed Hassan Hosseini Navid Rabiee Mojtaba Bagherzadeh 《Journal of polymer science. Part A, Polymer chemistry》2020,58(15):2062-2073
A number of synthetic hydrogels suffer from low mechanical strength. Despite of the recent advances in the fabrication of tough hydrogels, it is still a great challenge to simultaneously construct high stretchability, and self-adhesive and self-healing capability in a hydrogel. Herein, a new type of double network hydrogel was prepared based on irreversible cross-linking of polyacrylamide chains and Schiff-base reversible cross-linking between glycidyl methacrylate-grafted ethylenediamine and oxidized sodium alginate (OSA). The combination of both cross-linkings and their synergistic effect provided a novel hydrogel with high strength, stretchable, rapid self-healing, and self-adhesiveness to different material. Besides, the hydrogels with diverse OSA content could maintain their original shapes after loading–unloading tensile test. The resulting hydrogel has a great potential in various fields for supporting and load-bearing substance. 相似文献
42.
Faroughi Niya Homayoun Hazeri Nourallah Fatahpour Maryam Maghsoodlou Malek Taher 《Research on Chemical Intermediates》2020,46(7):3651-3666
Research on Chemical Intermediates - A novel magnetically heterogeneous nanocatalyst has been successfully synthesized via the immobilization of piperazine on tris (hydroxymethyl)... 相似文献
43.
Kowsari Elaheh Morad Fariba Seifvand Naemeh Bazri Behrouz Karimi Maryam 《Research on Chemical Intermediates》2020,46(2):1217-1234
Research on Chemical Intermediates - A nanostructured composite material was produced through sol–gel-assisted ionic liquid (IL) synthesized TiO2, WO3 and functionalized reduced graphene... 相似文献
44.
Optimization Letters - SENSitivity Encoding (SENSE) is an effective mathematical formulation for reconstructing under-sampled MRI data obtained in Parallel Magnetic Resonance Imaging (Parallel... 相似文献
45.
Mahsa Kiani Mojtaba Bagherzadeh Soraia Meghdadi Farzaneh Fadaei-Tirani Maryam Babaie Kurt Schenk-Joß 《应用有机金属化学》2020,34(11):e5911
The new Co(II) - carboxamide complex ( 1 ) and Co3O4 nanoparticles ( 2 ), by way of thermal decomposition of ( 1 ) have been efficiently synthesised in the environment-friendly. X-ray diffraction reveals a slightly distorted octahedral coordination of cobalt (four nitrogens and two oxygens) in ( 1 ) and regular octahedral or tetrahedral ones (oxygens only) in ( 2 ). The investigation of ( 1 ) and ( 2 ) in the Mizoroki-Heck and epoxidation of alkens reactions showed them both to be powerful, green and inexpensive catalysts. 相似文献
46.
47.
48.
49.
The purpose of this work was to synthesize and characterize a new magnetic polymer nanosphere‐supported palladium(II) acetate catalyst for reactions requiring harsh conditions. In this regard, an air‐stable, moisture‐stable and highly efficient heterogenized palladium was synthesized by the coordination of palladium(II) acetate with poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid)‐grafted modified magnetic nanoparticles with a core–shell structure. The structure of the newly developed catalyst was characterized using various techniques. The catalytic activity of the resultant nano‐organometallic catalyst was evaluated in Mizoroki–Heck and Suzuki–Miyaura reactions to afford the corresponding coupling products in good to excellent yields. High selectivity as well as outstanding turnover number (14 143, 4900) and turnover frequency (28 296, 7424) values were recorded for the catalyst in Suzuki–Miyaura and Mizoroki–Heck reactions, respectively. Magnetic separation and recycling of the catalyst for at least six runs became possible without any significant loss of efficiency or any detectable palladium leaching. 相似文献
50.
A novel hybrid system composed of sepiolite clay and cyclodextrin nanosponge (CDNS) was prepared via reaction of Cl‐functionalized sepiolite with amine‐functionalized CDNS. CDNS–sepiolite was then applied for immobilization of Pd(0) nanoparticles. The resulting hybrid system, Pd@CDNS‐sepiolite, was characterized using various techniques and successfully used as an efficient and heterogeneous catalyst for ligand‐ and copper‐free Sonogashira and Heck coupling reactions under mild reaction conditions. Recycling experiments confirmed that Pd@CDNS‐sepiolite was recyclable and could be used for several consecutive reaction runs with slight Pd leaching and loss of catalytic activity. 相似文献