全文获取类型
收费全文 | 251025篇 |
免费 | 2542篇 |
国内免费 | 454篇 |
专业分类
化学 | 135356篇 |
晶体学 | 3711篇 |
力学 | 11816篇 |
综合类 | 14篇 |
数学 | 29186篇 |
物理学 | 73938篇 |
出版年
2021年 | 2692篇 |
2020年 | 2955篇 |
2019年 | 3458篇 |
2018年 | 4617篇 |
2017年 | 4442篇 |
2016年 | 6307篇 |
2015年 | 3675篇 |
2014年 | 5631篇 |
2013年 | 11355篇 |
2012年 | 10059篇 |
2011年 | 11369篇 |
2010年 | 8413篇 |
2009年 | 8234篇 |
2008年 | 10464篇 |
2007年 | 10428篇 |
2006年 | 9190篇 |
2005年 | 8342篇 |
2004年 | 7715篇 |
2003年 | 6851篇 |
2002年 | 6637篇 |
2001年 | 6448篇 |
2000年 | 4854篇 |
1999年 | 3635篇 |
1998年 | 3081篇 |
1997年 | 3093篇 |
1996年 | 2978篇 |
1995年 | 2495篇 |
1994年 | 2665篇 |
1993年 | 2560篇 |
1992年 | 2880篇 |
1991年 | 2951篇 |
1990年 | 2848篇 |
1989年 | 2905篇 |
1988年 | 2759篇 |
1987年 | 2773篇 |
1986年 | 2610篇 |
1985年 | 3395篇 |
1984年 | 3439篇 |
1983年 | 2816篇 |
1982年 | 2863篇 |
1981年 | 2819篇 |
1980年 | 2590篇 |
1979年 | 2959篇 |
1978年 | 2910篇 |
1977年 | 3062篇 |
1976年 | 3114篇 |
1975年 | 2876篇 |
1974年 | 2827篇 |
1973年 | 2925篇 |
1972年 | 2175篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Irene Gouvinhas Nelson Machado Amadeo Girons‐Vilaplana Snia Gomes Teresa Carvalho Raúl Domínguez‐Perles Ana I. R. N. A. Barros 《Journal of Chemometrics》2016,30(9):548-558
The olive tree (Olea europaea L.) can be affected by Colletotrichum acutatum, causing a loss of yield and quality of the final products, whilst the incidence of this fungal infection depends on several factors, including cultivar susceptibility. Thus, the effect of C. acutatum infection in cultivars displaying different susceptibilities to this fungal disease (‘Galega Vulgar’ ‐ susceptible, ‘Cobrançosa’ ‐ moderately susceptible, ‘Picual’ ‐ tolerant) has been assessed through spectrophotometric methods and HPLC, while the FTIR spectra of the cuticles have been concomitantly registered, resorting to the ATR accessory. With the support of multivariate analysis, these spectra allowed to discriminate olives with distinct infection times, besides retrieving evidences concerning the different susceptibility of each cultivar, while these observations were reinforced by the spectrophotometric and chromatographic methods. Furthermore, the assessment of the phenolic profile evidenced individual compounds in the distinct cultivars, so as their variations in response to the fungal infection. 相似文献
73.
Russian Journal of Organic Chemistry - A new series of 4-(1H-imidazol-4-yl)-2-(substituted phenyl)-1,4-dihydrobenzo[4,5]imidazo[1,2-a]pyrimidines have been synthesized via a one-pot reaction... 相似文献
74.
Fedorov S. N. Kuzmich A. S. Agafonova I. G. Sabutskii Yu. E. Guzii A. G. Popov R. S. Ogurtsov V. A. Rakitin O. A. Polonik S. G. 《Russian Chemical Bulletin》2022,71(3):489-495
Russian Chemical Bulletin - Nucleophilic substitution of the chlorine atom in 4,5-dichloro-1,2-dithiol-3-one using 1-thio-β-d-glucopyranose and its 2,3,4,6-tetra-O-acetyl derivative in... 相似文献
75.
Akhiyarov A. A. Lobov A. N. Chernikova I. B. Ivanov S. P. 《Russian Journal of General Chemistry》2022,92(2):154-160
Russian Journal of General Chemistry - The constants of acid-base equilibrium of 6-methyluracil-5-carbonitrile in water were determined spectrophotometrically. For the first time,... 相似文献
76.
Tkachev V. V. Sayapin Yu. A. Gusakov E. A. Tupaeva I. O. Krasnikova T. A. Shilov G. V. Komissarov V. N. Aldoshin S. M. Minkin V. I. 《Russian Journal of General Chemistry》2022,92(2):206-211
Russian Journal of General Chemistry - Acylation of 5,7-di(tert-butyl)-2-{5,8-dimethyl-4-[(3,5-dimethylphenyl)amino]quinolin-2-yl}-3-[(3,5-dimethylphenyl)amino]tropone leads to... 相似文献
77.
Milutka M. S. Burlov A. S. Vlasenko V. G. Koshchienko Yu. V. Korshunova E. V. Uraev A. I. Trigub A. L. Zubenko A. A. Klimenko A. I. Gusev A. N. 《Russian Journal of General Chemistry》2022,92(7):1297-1308
Russian Journal of General Chemistry - Azomethines were synthesized from 2,4,6-trimethylaniline, salicylaldehyde, and its 3(5)-halogen derivatives, as well as their complexes with zinc(II) (ZnL2).... 相似文献
78.
Kalinin A. A. Sharipova S. M. Islamova L. N. Fazleeva G. M. Busyurova D. N. Sharipova A. V. Fominykh O. D. Balakina M. Yu. 《Russian Chemical Bulletin》2022,71(5):1009-1018
Russian Chemical Bulletin - Two new D—π—A chromophores with the tricyanofuranyl acceptor (A), an amphi-divinyl quinoxaline π-electron conjugated bridge, and the carbazole or... 相似文献
79.
do Nascimento Ticiano Gomes Borges Arthur Luy Tavares Ferreira de Almeida Lara Mendes Ribeiro Êurica Adélia Nogueira Silva Fernanda Geny Calheiros da Costa Silva Valdemir do Nascimento Prata Ana Paula Basílio-Júnior Irinaldo Diniz Goulart Marília Oliveira Fonseca Morilla Demetrius Peireira de Freitas Johnnatan Duarte Aragão Cícero Flávio Soares 《Journal of Thermal Analysis and Calorimetry》2022,147(21):11949-11963
Journal of Thermal Analysis and Calorimetry - This work prepared and characterized microcapsule of Uncaria tomentosa (UT) in order to standardize a spray-dryer Uncaria tomentosa extract. The UT... 相似文献
80.
Juan Tapia-P Yipeng Cao Prof. Jaime Gallego Prof. Jorge M. Osorio-Guillén Prof. Dane Morgan Prof. Juan F. Espinal 《Chemphyschem》2022,23(11):e202200152
There is an ongoing effort to replace rare and expensive noble-element catalysts with more abundant and less expensive transition metal oxides. With this goal in mind, the intrinsic defects of a rhombohedral perovskite-like structure of LaMnO3 and their implications on CO catalytic properties were studied. Surface thermodynamic stability as a function of pressure (P) and temperature (T) were calculated to find the most stable surface under reaction conditions (P=0.2 atm, T=323 K to 673 K). Crystallographic planes (100), (111), (110), and (211) were evaluated and it was found that (110) with MnO2 termination was the most stable under reaction conditions. Adsorption energies of O2 and CO on (110) as well as the effect of intrinsic defects such as Mn and O vacancies were also calculated. It was found that O vacancies favor the interaction of CO on the surface, whereas Mn vacancies can favor the formation of carbonate species. 相似文献