全文获取类型
收费全文 | 143976篇 |
免费 | 4819篇 |
国内免费 | 2852篇 |
专业分类
化学 | 82295篇 |
晶体学 | 2243篇 |
力学 | 6254篇 |
综合类 | 164篇 |
数学 | 14264篇 |
物理学 | 46427篇 |
出版年
2021年 | 1139篇 |
2020年 | 1420篇 |
2019年 | 1283篇 |
2018年 | 1230篇 |
2017年 | 1107篇 |
2016年 | 2134篇 |
2015年 | 1840篇 |
2014年 | 2357篇 |
2013年 | 6085篇 |
2012年 | 5080篇 |
2011年 | 6100篇 |
2010年 | 3864篇 |
2009年 | 3592篇 |
2008年 | 5198篇 |
2007年 | 5119篇 |
2006年 | 5209篇 |
2005年 | 4904篇 |
2004年 | 4214篇 |
2003年 | 3773篇 |
2002年 | 3686篇 |
2001年 | 4065篇 |
2000年 | 3093篇 |
1999年 | 2659篇 |
1998年 | 2215篇 |
1997年 | 2177篇 |
1996年 | 2164篇 |
1995年 | 2067篇 |
1994年 | 1840篇 |
1993年 | 1748篇 |
1992年 | 1957篇 |
1991年 | 1912篇 |
1990年 | 1818篇 |
1989年 | 1802篇 |
1988年 | 1800篇 |
1987年 | 1744篇 |
1986年 | 1649篇 |
1985年 | 2192篇 |
1984年 | 2302篇 |
1983年 | 1911篇 |
1982年 | 2226篇 |
1981年 | 2046篇 |
1980年 | 2084篇 |
1979年 | 2064篇 |
1978年 | 2190篇 |
1977年 | 2094篇 |
1976年 | 2120篇 |
1975年 | 2054篇 |
1974年 | 1899篇 |
1973年 | 2106篇 |
1972年 | 1283篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Li Y. Shi W. H. Dong L. M. Xu S. X. Huang H. J. Yin J. R. 《Journal of Applied Spectroscopy》2022,89(3):534-541
Journal of Applied Spectroscopy - Sr3B2O6:Dy3+, Eu3+ single-matrix white-light-emitting materials are prepared using the high-temperature solid-state method. The microstructure, emission spectrum,... 相似文献
12.
Yi-Tong Xu Tian-Yang Zhang Zheng Li Xiang-Nan Liu Yuan-Cheng Zhu Wei-Wei Zhao Hong-Yuan Chen Jing-Juan Xu 《Electroanalysis》2022,34(6):947-955
Photoelectrochemical (PEC) cytosensors, a combination of the PEC process and the living-cell assay, have emerged as a powerful tool in the analytical and biological science. This mini review provides a brief introduction of this arena and summaries the key steps about the development of PEC cytosensors with representative examples, followed by future prospects based on our own opinions. 相似文献
13.
Ajit Kumar Singh Seulgi Ji Baghendra Singh Chittaranjan Das Heechae Choi Prashanth W. Menezes Arindam Indra 《Materials Today Chemistry》2022
Herein, we report a Mott-Schottky catalyst by entrapping cobalt nanoparticles inside the N-doped graphene shell (Co@NC). The Co@NC delivered excellent oxygen evolution activity with an overpotential of merely 248 mV at a current density of 10 mA cm–2 with promising long-term stability. The importance of Co encapsulated in NC has further been demonstrated by synthesizing Co nanoparticles without NC shell. The synergy between the hexagonal close-packed (hcp) and face-centered cubic (fcc) Co plays a major role to improve the OER activity, whereas the NC shell optimizes the electronic structure, improves the electron conductivity, and offers a large number of active sites in Co@NC. The density functional theory calculations have revealed that the hcp Co has a dominant role in the surface reaction of electrocatalytic oxygen evolution, whereas the fcc phase induces the built-in electric field at the interfaces with N-doped graphene to accelerate the H+ ion transport. 相似文献
14.
Li Quanxin Li Zheng He Cheng Sun Huilin Tan Shengheng Zhang Hua 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2105-2115
Journal of Radioanalytical and Nuclear Chemistry - The simplified 8-oxide system (SiO2-B2O3-Na2O-Al2O3-CaO-TiO2-MoO3-La2O3) has been prepared under two types of cooling methods, and analyzed with... 相似文献
15.
Li Jun Zheng Dayong Wei Ning Sun Yunfeng Liu Li Yuan Yuan Jiang Qinghua 《Chemistry of Natural Compounds》2022,58(4):650-652
Chemistry of Natural Compounds - A new quassinoid, dehydrobruceantinol B (1), was isolated from the seeds of Brucea javanica, together with two known compounds, bruceantinol (2) and bruceine A (3).... 相似文献
16.
Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.
相似文献17.
Dr. Yong-Sheng Wei Dr. Liming Sun Miao Wang Dr. Jinhua Hong Dr. Lianli Zou Hongwen Liu Dr. Yu Wang Dr. Mei Zhang Dr. Zheng Liu Prof. Yinwei Li Prof. Satoshi Horike Prof. Kazu Suenaga Prof. Qiang Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(37):16147-16156
Understanding the thermal aggregation behavior of metal atoms is important for the synthesis of supported metal clusters. Here, derived from a metal–organic framework encapsulating a trinuclear FeIII2FeII complex (denoted as Fe3) within the channels, a well-defined nitrogen-doped carbon layer is fabricated as an ideal support for stabilizing the generated iron nanoclusters. Atomic replacement of FeII by other metal(II) ions (e.g., ZnII/CoII) via synthesizing isostructural trinuclear-complex precursors (Fe2Zn/Fe2Co), namely the “heteroatom modulator approach”, is inhibiting the aggregation of Fe atoms toward nanoclusters with formation of a stable iron dimer in an optimal metal–nitrogen moiety, clearly identified by direct transmission electron microscopy and X-ray absorption fine structure analysis. The supported iron dimer, serving as cooperative metal–metal site, acts as efficient oxygen evolution catalyst. Our findings offer an atomic insight to guide the future design of ultrasmall metal clusters bearing outstanding catalytic capabilities. 相似文献
18.
19.
20.