全文获取类型
收费全文 | 22404篇 |
免费 | 4185篇 |
国内免费 | 3459篇 |
专业分类
化学 | 16892篇 |
晶体学 | 384篇 |
力学 | 1217篇 |
综合类 | 317篇 |
数学 | 2570篇 |
物理学 | 8668篇 |
出版年
2024年 | 22篇 |
2023年 | 434篇 |
2022年 | 547篇 |
2021年 | 730篇 |
2020年 | 920篇 |
2019年 | 938篇 |
2018年 | 818篇 |
2017年 | 844篇 |
2016年 | 1091篇 |
2015年 | 1177篇 |
2014年 | 1344篇 |
2013年 | 1780篇 |
2012年 | 2032篇 |
2011年 | 2231篇 |
2010年 | 1642篇 |
2009年 | 1601篇 |
2008年 | 1679篇 |
2007年 | 1505篇 |
2006年 | 1304篇 |
2005年 | 1111篇 |
2004年 | 869篇 |
2003年 | 719篇 |
2002年 | 715篇 |
2001年 | 631篇 |
2000年 | 524篇 |
1999年 | 416篇 |
1998年 | 345篇 |
1997年 | 289篇 |
1996年 | 259篇 |
1995年 | 271篇 |
1994年 | 249篇 |
1993年 | 173篇 |
1992年 | 144篇 |
1991年 | 128篇 |
1990年 | 119篇 |
1989年 | 86篇 |
1988年 | 59篇 |
1987年 | 57篇 |
1986年 | 47篇 |
1985年 | 39篇 |
1984年 | 27篇 |
1983年 | 30篇 |
1982年 | 22篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1976年 | 6篇 |
1975年 | 6篇 |
1957年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
81.
Hierarchical‐Structured Anatase‐Titania/Cellulose Composite Sheet with High Photocatalytic Performance and Antibacterial Activity 下载免费PDF全文
Dr. Yan Luo Prof. Dr. Jianguo Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(6):2568-2575
Bulk hierarchical anatase‐titania/cellulose composite sheets were fabricated by subjecting an ultrathin titania gel film pre‐deposited filter paper to a solvo‐co‐hydrothermal treatment by using titanium butoxide as the precursor to grow anatase‐titania nanocrystallites on the cellulose nanofiber surfaces. The titanium butoxide specie is firstly absorbed onto the nanofibers of the cellulose substance through a solvothermal process, which was thereafter hydrolyzed and crystallized upon the subsequent hydrothermal treatment, leading to the formation of fine anatase‐titania nanoparticles with sizes of 2–5 nm uniformly anchored on the cellulose nanofibers. The resulting anatase‐titania/cellulose composite sheet shows a significant photocatalytic performance towards degradation of a methylene blue dye, and introduction of silver nanoparticles into the composite sheet yields an Ag‐NP/anatase‐titania/cellulose composite material possessing excellent antibacterial activity against both Gram‐positive and Gram‐negative bacteria. 相似文献
82.
83.
Bimetallic Gold(I) Complexes with Ethynyl‐Helicene and Bis‐Phosphole Ligands: Understanding the Role of Aurophilic Interactions in their Chiroptical Properties 下载免费PDF全文
Dr. Mehdi El Sayed Moussa Dr. Hui Chen Zuoyong Wang Dr. Monika Srebro‐Hooper Dr. Nicolas Vanthuyne Dr. Soizic Chevance Prof. Christian Roussel Prof. J. A. Gareth Williams Prof. Jochen Autschbach Prof. Régis Réau Prof. Zheng Duan Dr. Christophe Lescop Dr. Jeanne Crassous 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(17):6075-6086
Monometallic gold(I)‐alkynyl‐helicene complexes ( 1 a , b ) and bimetallic gold(I)‐alkynyl‐helicene architectures featuring the presence ( 2 a , b ) or absence ( 3 a , b ) of aurophilic intramolecular interactions were prepared by using different types of phosphole ligands (mono‐phosphole L1 or bis‐phospholes L2 , 3 ). The influence of the AuI d10 metal center(s) on the electronic, photophysical, and chiroptical properties of these unprecedented phosphole‐gold(I)‐alkynyl‐helicene complexes was examined. Experimental and theoretical results highlight the importance of ligand‐to‐ligand‐type charge transfers and the strong effect of the presence or absence of AuI–AuI interactions in 2 a , b . 相似文献
84.
85.
86.
Fen Yu Dr. Xuan Fang Huimin Jia Miaoxing Liu Xiaotong Shi Chaowen Xue Dr. Tingtao Chen Prof. Zhipeng Wei Prof. Fang Fang Prof. Hui Zhu Prof. Hongbo Xin Prof. Jing Feng Prof. Xiaolei Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(24):8053-8058
For the first time, the influence of different types of atoms (Zn and O) on the antibacterial activities of nanosized ZnO was quantitatively evaluated with the aid of a 3D‐printing‐manufactured evaluation system. Two different outermost atomic layers were manufactured separately by using an ALD (atomic layer deposition) method. Interestingly, we found that each outermost atomic layer exhibited certain differences against gram‐positive or gram‐negative bacterial species. Zinc atoms as outermost layer (ZnO?Zn) showed a more pronounced antibacterial effect towards gram‐negative E. coli (Escherichia coli), whereas oxygen atoms (ZnO?O) showed a stronger antibacterial activity against gram‐positive S. aureus (Staphylococcus aureus). A possible antibacterial mechanism has been comprehensively discussed from different perspectives, including Zn2+ concentrations, oxygen vacancies, photocatalytic activities and the DNA structural characteristics of different bacterial species. 相似文献
87.
88.
Christian W. Pester Justin E. Poelma Benjaporn Narupai Shrayesh N. Patel Gregory M. Su Thomas E. Mates Yingdong Luo Christopher K. Ober Craig J. Hawker Edward J. Kramer 《Journal of polymer science. Part A, Polymer chemistry》2016,54(2):253-262
In an attempt to create a polymer brush-based platform for the systematic study for anti-biofouling surfaces, the benefits of surface initiated, visible light-mediated radical polymerization are utilized to fabricate well-defined, chemically ambiguously patterned surfaces. A variety of analytical tools are used to illustrate the precise tuning of surface chemistry and thoroughly characterize spatially well-defined, hydrophilic/hydrophobic surfaces composed of poly(ethylene glycol methacrylate) and poly(trifluoroethyl methacrylate) with chemical definition on the micron scale. Advantages of both visible light-mediated photopolymerization and traditional copper-catalyzed atom transfer radical polymerization are combined to achieve both high spatial control and expanded monomer tolerance. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 253–262 相似文献
89.
Copper‐Catalyzed Difunctionalization of Activated Alkynes by Radical Oxidation–Tandem Cyclization/Dearomatization to Synthesize 3‐Trifluoromethyl Spiro[4.5]trienones 下载免费PDF全文
Dr. Hui‐Liang Hua Yu‐Tao He Yi‐Feng Qiu Ying‐Xiu Li Bo Song Pin Gao Xian‐Rong Song Dong‐Hui Guo Prof. Dr. Xue‐Yuan Liu Prof. Dr. Yong‐Min Liang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(4):1468-1473
A copper‐catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent sodium trifluoromethanesulfinate (NaSO2CF3 or Langlois’ reagent) has been developed incorporating a tandem cyclization/dearomatization process. This strategy affords a straightforward route to synthesis of 3‐(trifluoromethyl)‐spiro[4.5]trienones, and presents an example of difunctionalization of alkynes for simultaneous formation of two carbon–carbon single bonds and one carbon–oxygen double bond. 相似文献
90.