全文获取类型
收费全文 | 111062篇 |
免费 | 17266篇 |
国内免费 | 11382篇 |
专业分类
化学 | 75515篇 |
晶体学 | 1178篇 |
力学 | 7207篇 |
综合类 | 834篇 |
数学 | 14006篇 |
物理学 | 40970篇 |
出版年
2024年 | 95篇 |
2023年 | 2125篇 |
2022年 | 2387篇 |
2021年 | 3481篇 |
2020年 | 4288篇 |
2019年 | 4077篇 |
2018年 | 3583篇 |
2017年 | 3344篇 |
2016年 | 5006篇 |
2015年 | 5048篇 |
2014年 | 6058篇 |
2013年 | 7998篇 |
2012年 | 9779篇 |
2011年 | 10123篇 |
2010年 | 6956篇 |
2009年 | 6717篇 |
2008年 | 7083篇 |
2007年 | 6387篇 |
2006年 | 5912篇 |
2005年 | 5096篇 |
2004年 | 4005篇 |
2003年 | 3114篇 |
2002年 | 2823篇 |
2001年 | 2310篇 |
2000年 | 2045篇 |
1999年 | 2347篇 |
1998年 | 1989篇 |
1997年 | 1809篇 |
1996年 | 1853篇 |
1995年 | 1718篇 |
1994年 | 1542篇 |
1993年 | 1316篇 |
1992年 | 1133篇 |
1991年 | 1019篇 |
1990年 | 846篇 |
1989年 | 702篇 |
1988年 | 524篇 |
1987年 | 488篇 |
1986年 | 444篇 |
1985年 | 422篇 |
1984年 | 279篇 |
1983年 | 262篇 |
1982年 | 192篇 |
1981年 | 149篇 |
1980年 | 107篇 |
1979年 | 65篇 |
1977年 | 69篇 |
1976年 | 70篇 |
1975年 | 77篇 |
1973年 | 73篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Zhengcheng Wang Shangyan Zhou Wei Liao Qian Zhou Meida Chen Jin Long Prof. Qingmei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202201987
The designs of efficient and inexpensive Pt-based catalysts for methanol oxidation reaction (MOR) are essential to boost the commercialization of direct methanol fuel cells. Here, the highly catalytic performance PtFe alloys supported on multiwalled carbon nanotubes (MWCNTs) decorating nitrogen-doped carbon (NC) have been successfully prepared via co-engineering of the surface composition and electronic structure. The Pt1Fe3@NC/MWCNTs catalyst with moderate Fe3+ feeding content (0.86 mA/mgPt) exhibits 2.26-fold enhancement in MOR mass activity compared to pristine Pt/C catalyst (0.38 mA/mgPt). Furthermore, the CO oxidation initial potential of Pt1Fe3@NC/MWCNTs catalyst is lower relative to Pt/C catalyst (0.71 V and 0.80 V). Benefited from the optimal surface compositions, the anti-corrosion ability of MWCNT, strong electron interaction between PtFe alloys and MWCNTs and the N-doped carbon (NC) layer, the Pt1Fe3@NC/MWCNTs catalyst presents an improved MOR performance and anti-CO poisoning ability. This study would open up new perspective for designing efficient electrocatalysts for the DMFCs field. 相似文献
82.
Hu Bing Guo Fangsong Li Shanrong Yang Can Lin Wei Zhang Jinshui Hou Yidong Wang Xinchen 《Research on Chemical Intermediates》2022,48(6):2295-2311
Research on Chemical Intermediates - Element doping has demonstrated an effective strategy for enhancing photocatalytic performance of carbon nitride (CN). Herein, we reported that oxygen-doped CN... 相似文献
83.
Meihua Shen Dr. Xinpeng Zhao Dr. Lu Han Nanxi Jin Prof. Song Liu Prof. Tao Jia Prof. Zhijun Chen Prof. Xiuhua Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(20):e202104137
Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air−water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar-thermal material di-cyan substituted 5,12-dibutylquinacridone (DCN−4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper. The DCN−4CQA@Paper combines desired chemical and physical properties, broadband light-absorbing, and shape-conforming abilities that render efficient photothermic vaporization. Notably, synergetic coupling of solar-steam and solar-electricity technologies by integrating DCN−4CQA@Paper and the thermoelectric devices is realized without trade-offs, highlighting the practical consideration toward more impactful solar heat exploitation. Such solar distillation and low-grade heat-to-electricity generation functions can provide potential opportunities for fresh water and electricity supply in off-grid or remote areas. 相似文献
84.
Emerging Trends in Fluorescence Bioimaging of Divalent Metal Cations Using Small-Molecule Indicators
Mingqiao Liu Junwei Zhang Zhixing Chen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(45):e202200587
Visualization of cation dynamics inside a living system represent a major breakthrough at the crossroad of chemistry and cellular physiology. Since the inception of BAPTA-based cellular calcium indicators in the 1980s, generations of chemical and genetically encoded ion indicators spanning the visible spectrum have been developed. In this article, we bring up three emerging concepts in this field: 1. red-shifting cation indicators towards far-red and near-infrared (NIR) channels; 2. directing the indicators to various subcellular localizations; 3. lowering the phototoxicity of indicators for long term recording. These initiatives collectively echo the advocate of 4D cellular physiology, where biological processes within living systems can be panoramically unveiled under 3D, long-term, and multi-channel imaging with unprecedented spatial and temporal resolution. This outlook poses exciting challenges and opportunities for chemists to upgrade the toolkit of fluorescent indicators as key enablers for a new era of imageomics. 相似文献
85.
86.
Hua Saixiang Zhu Huichao Wang Xiao Wu Mingyuan Wu Qingyun Liu Jiuyi Yang Jianjun Zhang Jianan 《Cellulose (London, England)》2022,29(13):7465-7475
Cellulose - Ultraviolet (UV) protective cotton fabric is a convenient and reliable way to protect human body from sunlight. Herein, a polymerizable UV-absorber,... 相似文献
87.
Nonlinear Dynamics - The perovskite solar cell (PSC) is one of the most promising photovoltaic candidates along with the highly increasing demand for green electricity. One of the main concerns... 相似文献
88.
89.
Bidirectional and Unidirectional Negative Differential Thermal Resistance Effect in a Modified Lorentz Gas Model 下载免费PDF全文
Recently,the negative differential thermal resistance effect was discovered in a homojunction made of a negative thermal expansion material,which is very promising for realizing macroscopic thermal transistors.Similar to the Monte Carlo phonon simulation to deal with grain boundaries,we introduce positive temperature-dependent interface thermal resistance in the modified Lorentz gas model and find negative differential thermal resistance effect.In the homojunction,we reproduce a pair of equivalent negative differential thermal resistance effects in different temperature gradient directions.In the heterojunction,we realize the unidirectional negative differential thermal resistance effect,and it is accompanied by the super thermal rectification effect.Using this new way to achieve high-performance thermal devices is a new direction,and will provide extensive reference and guidance for designing thermal devices. 相似文献
90.
根据教育部颁布的《普通高中物理课程标准(2017年版)》,在上海市物理教育教学基地(上海高校“立德树人”人文社会科学重点研究基地)的大力支持下,由上海市教育委员会组织编写的上海高中物理非统编教材进行了正式使用前的试教试用活动,此教材是在上海高中物理“二期课改”教材的基础上全面改写而成的.单元教学设计已成为当前教学设计的焦点问题,以《物理·必修》(第三册)静电场单元为例,详细阐述了“教学问题链”的设计理念,希望与广大一线教师交流试教试用的心得与反思,推动新课改课堂转型. 相似文献