全文获取类型
收费全文 | 4369篇 |
免费 | 725篇 |
国内免费 | 413篇 |
专业分类
化学 | 3117篇 |
晶体学 | 42篇 |
力学 | 269篇 |
综合类 | 46篇 |
数学 | 424篇 |
物理学 | 1609篇 |
出版年
2024年 | 11篇 |
2023年 | 122篇 |
2022年 | 141篇 |
2021年 | 171篇 |
2020年 | 209篇 |
2019年 | 161篇 |
2018年 | 139篇 |
2017年 | 119篇 |
2016年 | 195篇 |
2015年 | 169篇 |
2014年 | 240篇 |
2013年 | 265篇 |
2012年 | 378篇 |
2011年 | 360篇 |
2010年 | 268篇 |
2009年 | 265篇 |
2008年 | 282篇 |
2007年 | 272篇 |
2006年 | 272篇 |
2005年 | 183篇 |
2004年 | 128篇 |
2003年 | 110篇 |
2002年 | 98篇 |
2001年 | 86篇 |
2000年 | 86篇 |
1999年 | 100篇 |
1998年 | 90篇 |
1997年 | 89篇 |
1996年 | 65篇 |
1995年 | 90篇 |
1994年 | 74篇 |
1993年 | 45篇 |
1992年 | 58篇 |
1991年 | 45篇 |
1990年 | 40篇 |
1989年 | 26篇 |
1988年 | 16篇 |
1987年 | 14篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有5507条查询结果,搜索用时 15 毫秒
871.
Yuzhi Xu Yanfei Zhang Huihui Yang Wen Yin Leli Zeng Shuo Fang Si-Yang Liu Zong Dai Xiaoyong Zou Yihang Pan 《中国化学快报》2022,33(2):968-972
A reliable and sensitive strategy which can assess nucleic acid levels in living cells would be essential for fundamental research of biomedical applications. Some nanomaterial-based fluorescence biosensors recently developed for detecting nucleic acids, however, are often with expensive, complicated and timeconsuming preparation process. Here, by using a facile bottom-up synthesis method, a two-dimensional(2 D) coordination polymer(CP) nanosheet, [Cu(tz)](Htz = 1,2,4-triazole), was successfully... 相似文献
872.
873.
H.-R. Xia L.-J. Hu J.-H. Zou L.-X. Li H. Yu X.-L. Meng L. Zhu W.-T. Yu 《Crystal Research and Technology》1998,33(5):807-816
Neodymium-doped yttrium orthovanadate NdxY1—xVO4(NYV), with x = 0.025, crystallizes with a zircon-type structure in the tetragonal system conforming to the space group I41/amd. The lattice constants are a = b = 0.7123 ± 0.0005 and c = 0.6292 ± 0.0005 nm at room temperature. There are the four formulas per unit cell. The lattice-vibration and transmissivity spectra show that the NYV crystal is a good laser host crystal, which provides a suitable crystal field for the active ions. A strong absorption at 808 nm and the stimulated emission at 1.06 μm have provided the practical application as a laser crystal. Also, a strong fluorescent radiation at 0.408 μm, corresponding to a transition 4D3/2 → 4I13/2, is observed. 相似文献
874.
875.
Hongbin Li Wenke Zhang Xi Zhang Jiacong Shen Bingbing Liu Chunxiao Gao Guangtian Zou 《Macromolecular rapid communications》1998,19(12):609-611
The elastic properties of poly(vinyl alcohol) (PVA) were investigated on the nanoscale using the new technique of single molecule force spectroscopy by atomic force microscopy (AFM). It was found that the elastic properties of PVA molecules scale linearly with their contour lengths. This finding corroborates that the deformation of individual PVA chains is measured. The force spectra of PVA show a kink at around 200 pN and cannot be fitted by an extended Langevin function. The deviation of the elastic behavior of PVA from a freely jointed chain model may indicate the presence of a suprastructure of PVA in NaCl solution. 相似文献
876.
Yang‐Feng Li Xiao‐Dong Zou 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(11):m471-m472
A new borogermanate, viz. piperazine‐1,4‐diium difluorononaoxotrigermaniumdiboron, (C4H12N2)[(GeO2)3(BO1.5F)2], was solvo/hydrothermally synthesized. The crystal structure consists of layers composed of three‐membered‐ring Ge3O9 subunits and nine‐membered‐ring channels formed by six GeO4 tetrahedra and three BO3F tetrahedral pairs. The diprotonated piperazine cations, which lie about inversion centres, are located between adjacent layers and connect the layers via hydrogen bonds. 相似文献
877.
Mixed packing capillary electrochromatography (MP CEC) with the stationary phase comprising a physical mixture of strong cation exchange (SCX) phase and octadecysilyl (ODS) phase was developed. With the existence of a sulfonic acid group on the surface of SCX, not only could the electroosmotic flow (EOF) remain high at low pH, but also the hydrophilicity of the stationary phase was increased greatly, leading to broad adaptable ranges of both pH and organic modifier concentration in the mobile phase. At the same time, with the coexistence of C18 on the surface of ODS, both the retention and the resolution of samples were improved. Accordingly, MP CEC combined the advantages of both SCX and ODS columns. Effects of operation parameters on EOF and the capacity factors of solutes as well as the retention mechanism of such a column were studied systematically. In addition, MP CEC columns were used in the analysis of strong polar solutes as well as for the high speed separation of acidic, basic, and neutral compounds in a single run. 相似文献
878.
Zhou Peng He Junying Zou Yuqin Wang Yanyong Xie Chao Chen Ru Zang Shuangquan Wang Shuangyin 《中国科学:化学(英文版)》2019,62(10):1365-1370
The oxygen evolution reaction(OER) with sluggish reaction kinetics and large overpotential is the critical reaction in water splitting that is promising for energy storage and conversion. Layered double hydroxides(LDHs), due to their unique lamellar structure and flexibility of chemical component, are very competing material candidates for OER. Herein, the morphology structure and the electronic structure of LDHs were simultaneously tuned to improve the OER catalytic activity by mild solvothermal reduction using ethylene glycol. The increased surface area, the introduction of oxygen vacancies and the construction of hierarchical structure greatly enhanced the electro-catalytic activity of LDHs for OER. The as-prepared LDHs showed a lower over-potential as low as 276 mV at a current density of 10 mA cm~(-2), and a small Tafel slope of 40.3 mV dec~(-1) accompanied with good stability. This work provides an efficient way to the design and optimization of advanced catalysts in the future. 相似文献
879.
Tieyan Si Xian Zou Zhiguang Wu Tianlong Li Xin Wang Krasnyuk Ivan Ivanovich Qiang He 《化学:亚洲杂志》2019,14(14):2460-2464
We report the bubble dragged microrocket consisting of functionalized multilayer polymer covered asymmetrically by platinum nanoparticles. The microrocket is pushed back during bubble growth over a small step and dragged forward over a big step during bubble explosion. Each bubble explosion induced a shock wave of gas which propagates in water at ultrafast speed. The bubble dragged microrocket can move along an approximate straight line instead of a fluctuating circle which is the trajectory of a bubble‐pushed microrocket in most cases, which makes it a promising candidate for drug delivery and simulating rod‐shaped bacteria. 相似文献
880.
Abstract:We study the spectrum of single-photon emission and scattering in a mixed optomechanical model which consists of both linear and quadratic optomechanical interactions. The spectra are calculated based on the exact long-time solutions of the single-photon emission and scattering processes in this system. We find that there exist some phonon sideband peaks in the spectra and there are some sub peaks around the phonon sideband peaks under proper parameter conditions. The correspondence between the spectral features and the optomechanical interactions is confirmed, and the optomechanical coupling strengths can be inferred by analyzing the resonance peaks and dips in the spectra. 相似文献