全文获取类型
收费全文 | 444篇 |
免费 | 7篇 |
国内免费 | 8篇 |
专业分类
化学 | 219篇 |
晶体学 | 4篇 |
力学 | 13篇 |
数学 | 136篇 |
物理学 | 87篇 |
出版年
2024年 | 5篇 |
2023年 | 8篇 |
2022年 | 14篇 |
2021年 | 27篇 |
2020年 | 37篇 |
2019年 | 49篇 |
2018年 | 15篇 |
2017年 | 11篇 |
2016年 | 15篇 |
2015年 | 10篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 19篇 |
2011年 | 23篇 |
2010年 | 10篇 |
2009年 | 11篇 |
2008年 | 12篇 |
2007年 | 19篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 17篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 6篇 |
2000年 | 7篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 7篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有459条查询结果,搜索用时 15 毫秒
381.
Thanh-Tung Duong Ta Quoc Tuan Dang Viet Anh Dung Nguyen Van Quy Dinh-Lam Vu Man Hoai Nam Nguyen Duc Chien Soon-Gil Yoon Anh-Tuan Le 《Current Applied Physics》2014,14(12):1607-1611
Polyaniline nanowires (PANI NWs) were deposited onto fluorine-doped tin oxide (FTO) glass substrate using the cyclic voltammetric method with aniline monomer precursor in HCl aqueous solution. The secondary oxidation peak plays an important role in polymerization of aniline monomer and the optimization of catalytic activity of PANI-based counter electrodes was achieved by controlling the number of cycles. The photovoltaic performance of the dye-sensitized solar cells (DSSCs) with PANI NWs counter electrodes (CEs) was optimized at 4th cycles, and then following parameters were obtained: Jsc = 17.2 mA cm−2, Voc = 0.71 V, FF = 59.3%, and efficiency (η) = 7.24%. While, Jsc = 14.7 mA cm−2, Voc = 0.77 V, FF = 70.6%, and efficiency (η) = 7.98% in cells with Pt CEs. The PANI NWs were attractive as an alternative CEs for the low-cost DSSCs instead of Pt. 相似文献
382.
Bennett GW Bousquet B Brown HN Bunce G Carey RM Cushman P Danby GT Debevec PT Deile M Deng H Dhawan SK Druzhinin VP Duong L Farley FJ Fedotovich GV Gray FE Grigoriev D Grosse-Perdekamp M Grossmann A Hare MF Hertzog DW Huang X Hughes VW Iwasaki M Jungmann K Kawall D Khazin BI Krienen F Kronkvist I Lam A Larsen R Lee YY Logashenko I McNabb R Meng W Miller JP Morse WM Nikas D Onderwater CJ Orlov Y Ozben CS Paley JM Peng Q Polly CC Pretz J Prigl R Zu Putlitz G Qian T Redin SI Rind O Roberts BL 《Physical review letters》2004,92(16):161802
The anomalous magnetic moment of the negative muon has been measured to a precision of 0.7 ppm (ppm) at the Brookhaven Alternating Gradient Synchrotron. This result is based on data collected in 2001, and is over an order of magnitude more precise than the previous measurement for the negative muon. The result a(mu(-))=11 659 214(8)(3) x 10(-10) (0.7 ppm), where the first uncertainty is statistical and the second is systematic, is consistent with previous measurements of the anomaly for the positive and the negative muon. The average of the measurements of the muon anomaly is a(mu)(exp)=11 659 208(6) x 10(-10) (0.5 ppm). 相似文献
383.
George Eng Xueqing Song Quyen Duong Daniel Strickman Jacqulin Glass Leopold May 《应用有机金属化学》2003,17(4):218-225
384.
385.
386.
387.
Qui-Nhi Duong;Lukas Schifferer;Olga García Mancheño; 《European journal of organic chemistry》2019,2019(31-32):5452-5461
A nucleophile screening for the organocatalyzed enantioselective Reissert-type dearomatization of quinoline derivatives using chiral triazoles as anion-binding catalysts was realized. Our recently reported helical tetrakis(triazole) catalysts (TetraTri) have proven to be highly active in this type of reactions, however the methods were limited to nucleophiles with a N value of 10 according to the Mayr's nucleophilicity scale. In this study, different carbon-nucleophiles of varied nucleophilicity N-values were explored, allowing the identification of potential novel reaction partners with N >5 such as ketene thioacetals. Thus, a number of chiral 1,2-dihydroisoquinoline-thioesters with an enantioselectivity up to 92:8 er. were synthetized, which could easily be transformed into a more valuable amide derivative. 相似文献
388.
Thuc-Huy Duong;Xuan-Phong Ha;Warinthorn Chavasiri;Mehdi A. Beniddir;Grégory Genta-Jouve;Joël Boustie;Marylène Chollet-Krugler;Solenn Ferron;Hung-Huy Nguyen;Bohari Mohd Yamin;Bui-Linh-Chi Huynh;Pierre Le Pogam;Kim-Phi-Phung Nguyen; 《European journal of organic chemistry》2018,2018(19):2247-2253
The phytochemical investigation of the lichen Parmotrema sancti-angelii afforded three racemic compounds, sanctis A–C, which feature an original dibenzo-2,8-dioxabicyclo[3.3.1]nonane scaffold. These compounds were structurally characterized by extensive NMR spectroscopy analyses, comparison between experimental and theoretical NMR spectroscopic data, and X-ray crystallography. These metabolites are similar to procyanidin A and display a methyl group instead of a pendant aromatic ring at C-9, a so far unprecedented structural feature. A biosynthetic route to sanctis A–C is proposed. 相似文献
389.
A. I. Rakhimov A. V. Miroshnichenko Do Duong Phuong Thao 《Russian Journal of General Chemistry》2011,81(8):1640-1642
Unlike the saturated aliphatic and aromatic alcohols, allyl alcohol under the same conditions reacts with polyfluoroalkyl chlorosulfites to form not ethers, but polyfluorinated alcohols. The exception is polyfluoroalkyl chlorosulfites with the chain length of more than five carbon atoms. Allyl ethers of polyfluorinated alcohols of general formula CH2=CHCH2OCH2(CF2CF2)nH (n = 1–3) were obtained, when the reaction proceeded in the presence of potassium carbonate, owing to its participation in a specific orientation of the reaction centers in the resulting intermediate structure, which is easily transformed into allyl ethers of polyfluorinated alcohols. 相似文献
390.