全文获取类型
收费全文 | 3180篇 |
免费 | 389篇 |
国内免费 | 328篇 |
专业分类
化学 | 2112篇 |
晶体学 | 40篇 |
力学 | 263篇 |
综合类 | 37篇 |
数学 | 389篇 |
物理学 | 1056篇 |
出版年
2024年 | 7篇 |
2023年 | 48篇 |
2022年 | 87篇 |
2021年 | 114篇 |
2020年 | 111篇 |
2019年 | 89篇 |
2018年 | 109篇 |
2017年 | 98篇 |
2016年 | 124篇 |
2015年 | 155篇 |
2014年 | 177篇 |
2013年 | 226篇 |
2012年 | 257篇 |
2011年 | 286篇 |
2010年 | 192篇 |
2009年 | 184篇 |
2008年 | 194篇 |
2007年 | 203篇 |
2006年 | 184篇 |
2005年 | 140篇 |
2004年 | 78篇 |
2003年 | 77篇 |
2002年 | 82篇 |
2001年 | 73篇 |
2000年 | 61篇 |
1999年 | 51篇 |
1998年 | 58篇 |
1997年 | 51篇 |
1996年 | 68篇 |
1995年 | 45篇 |
1994年 | 43篇 |
1993年 | 28篇 |
1992年 | 28篇 |
1991年 | 32篇 |
1990年 | 42篇 |
1989年 | 25篇 |
1988年 | 19篇 |
1987年 | 15篇 |
1986年 | 12篇 |
1985年 | 5篇 |
1981年 | 2篇 |
1976年 | 2篇 |
1957年 | 1篇 |
1942年 | 1篇 |
1941年 | 1篇 |
1936年 | 4篇 |
1930年 | 2篇 |
1929年 | 1篇 |
1927年 | 1篇 |
1923年 | 1篇 |
排序方式: 共有3897条查询结果,搜索用时 15 毫秒
111.
Xiao-Min Nie Bo-Yang Shao Chen-Hui Qu Ling Zhou 《International Journal of Theoretical Physics》2013,52(9):3011-3019
We generalize usual second-order effective Hamiltonian approximation into third-order. Employing the generalized method, we propose a scheme to generate three-spin interaction using coupled cavity chain. We show that the third order term not only improves two parties interaction but also induces direct three-spin interaction which has not been simulated before. By controlling the frequency of laser field, one can obtain next nearest neighbor interaction on the same order with the nearest neighbor’s or the three-spin interaction on the same order as next nearest neighbor’s. 相似文献
112.
采用水热法和后续热处理合成出单斜相LaPO4以及LaPO4:Dy3+,通过XRD对样品进行物相分析,结果表明:所得样品为LaPO4,且XRD图谱及拉曼光谱中峰位的偏移表明Dy的存在,即Dy被掺杂到LaPO4基质中。通过研究用Dy对LaPO4进行不同量掺杂后其拉曼光谱的变化规律,进而找出用Dy对LaPO4进行不同量掺杂后其内部结构的变化规律。结果显示,用Dy对LaPO4进行不同量掺杂后,随着掺杂比例的增大,晶格畸变程度先上升后下降,且在镧镝物质的量比例为1∶0.06时对基体晶格结构影响最大。 相似文献
113.
Prof. Jiao Jiao Wenzheng Nie Tao Yu Fan Yang Prof. Dr. Qian Zhang Feierdaiweisi Aihemaiti Tingjun Yang Xuanyu Liu Jiachen Wang Prof. Dr. Pengfei Li 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(15):4817-4838
Continuous-flow multi-step synthesis takes the advantages of microchannel flow chemistry and may transform the conventional multi-step organic synthesis by using integrated synthetic systems. To realize the goal, however, innovative chemical methods and techniques are urgently required to meet the significant remaining challenges. In the past few years, by using green reactions, telescoped chemical design, and/or novel in-line separation techniques, major and rapid advancement has been made in this direction. This minireview summarizes the most recent reports (2017–2020) on continuous-flow synthesis of functional molecules. Notably, several complex active pharmaceutical ingredients (APIs) have been prepared by the continuous-flow approach. Key technologies to the successes and remaining challenges are discussed. These results exemplified the feasibility of using modern continuous-flow chemistry for complex synthetic targets, and bode well for the future development of integrated, automated artificial synthetic systems. 相似文献
114.
Miaofeng Huang Aihua Tang Zhenyin Wang Jingkun Shi Xiaoping Jiang Chubin Wan Xin Ju 《中国化学快报》2021,32(6):2009-2012
Aqueous electrolytes are safe, economic, and environmentally friendly. However, they have a narrow potential window. On the other hand, organic electrolytes exhibit good thermodynamic stability but are inflammable and moisture sensitive. In this study, we prepared water–PEG–lipid ternary electrolytes(TEs). To combine the advantages of water, polyethylene glycol(PEG) and propylene carbonate(PC). The nonflammable mixed electrolytes exhibited a wide potential window of about 2.8 V due to the beneficial effects of PEG and PC. Using these TEs, a lithium manganate–active carbon ion capacitor could be operated at 2.4 V with an energy density of 32 Wh/kg, based on the total active electrode material(current density of 3.3 m A/cm~2). This value was significantly higher than that achieved using an aqueous electrolyte, thereby rationalizing the higher energy density. 相似文献
115.
116.
117.
Computational insight into asymmetric uranyl‐salophen coordinated with α, β‐unsaturated aldehydes and ketones
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wen‐Bo Lan Xiao‐Feng Wang Li‐Ping He Yan‐Bin Meng Jun Li Bin Qiu Chang‐Ming Nie 《应用有机金属化学》2018,32(3)
The study of the catalytic activity and activation mechanism of asymmetric uranyl‐salophens with α, β‐unsaturated aldehydes or α, β‐unsaturated ketones, is a research hotspot. In this paper, the complexes of the uranyl–salophen(U‐S) modified by unilateral benzene, coordinated with cyclohexenone, cyclopentenone and acrolein, were investigated using density functional theory calculations at the level of B3LYP/6‐311G(d, p) basis set. The results showed that the uranyl‐salophen(U‐S) weakened the large π bond between C = C and C = O of the α, β‐unsaturated aldehydes and ketones, making the unsaturated aldehydes and ketones activated. In addition, the molecular‐recognition selectivity of the asymmetrical uranyl‐salophen for cyclohexenone and cyclopentenone were much higher than for acrolein. 相似文献
118.
Liu Zhenhong Li Xiaodong Liu Xiaoping 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(3):1701-1706
Journal of Radioanalytical and Nuclear Chemistry - An indicator with double tracers has been developed so as to improve the accuracy and stability of quantitative analysis of renal injury. The... 相似文献
119.
Die Chen Dr. Shu Yang Huayi Han Lingbo Song Dr. Dan Huang Xiao Lin Dr. Xiaoping Xu Dr. Qianfan Yang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(45):11627-11632
DNA computation is considered a fascinating alternative to silicon-based computers; it has evoked substantial attention and made rapid advances. Besides realizing versatile functions, implementing spatiotemporal control of logic operations, especially at the cellular level, is also of great significance to the development of DNA computation. However, developing simple and efficient methods to restrict DNA logic gates performing in live cells is still a challenge. In this work, a series of DNA logic gates was designed by taking full advantage of the diversity and programmability of the G-quadruplex (G4) structure. More importantly, by further using the high affinity and specific endocytosis of cells to aptamer G4, an INHIBIT logic gate has been realized whose operational site is precisely restricted to specific live cells. The design strategy might have great potential in the field of molecular computation and smart bio-applications. 相似文献
120.