全文获取类型
收费全文 | 11107篇 |
免费 | 463篇 |
国内免费 | 70篇 |
专业分类
化学 | 7614篇 |
晶体学 | 67篇 |
力学 | 247篇 |
数学 | 1600篇 |
物理学 | 2112篇 |
出版年
2023年 | 83篇 |
2022年 | 200篇 |
2021年 | 334篇 |
2020年 | 250篇 |
2019年 | 269篇 |
2018年 | 231篇 |
2017年 | 212篇 |
2016年 | 439篇 |
2015年 | 382篇 |
2014年 | 388篇 |
2013年 | 704篇 |
2012年 | 744篇 |
2011年 | 905篇 |
2010年 | 563篇 |
2009年 | 493篇 |
2008年 | 798篇 |
2007年 | 706篇 |
2006年 | 657篇 |
2005年 | 576篇 |
2004年 | 502篇 |
2003年 | 360篇 |
2002年 | 312篇 |
2001年 | 150篇 |
2000年 | 160篇 |
1999年 | 101篇 |
1998年 | 96篇 |
1997年 | 90篇 |
1996年 | 108篇 |
1995年 | 71篇 |
1994年 | 63篇 |
1993年 | 63篇 |
1992年 | 75篇 |
1991年 | 49篇 |
1990年 | 40篇 |
1989年 | 32篇 |
1988年 | 19篇 |
1987年 | 23篇 |
1986年 | 28篇 |
1985年 | 38篇 |
1984年 | 44篇 |
1983年 | 27篇 |
1982年 | 28篇 |
1981年 | 40篇 |
1980年 | 28篇 |
1979年 | 22篇 |
1978年 | 24篇 |
1977年 | 24篇 |
1976年 | 14篇 |
1973年 | 16篇 |
1972年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Guizellini Filipe Corrêa Franzin Bruno Trevizan da Silva Matheus Antonio Abra Luciana Mazotti Hojo Ossamu Pastre Iêda Aparecida Ribeiro Clóvis Augusto Paiva-Santos Carlos de Oliveira Fertonani Fernando Luis 《Journal of Thermal Analysis and Calorimetry》2021,143(1):47-60
Journal of Thermal Analysis and Calorimetry - The aim of this work is to synthesize and characterize a new structured silver–clay dried, calcined or sintered at different temperatures... 相似文献
2.
3.
4.
5.
Condeixa Lucas Dias Silva Pierry Moah Diego Farias Brenda Leiras Adriana 《Central European Journal of Operations Research》2022,30(3):921-940
Central European Journal of Operations Research - Societal awareness and legislation changes concerning sustainability have affected how organizations generate value for stakeholders, as well as... 相似文献
6.
da Silva Andre Luis Ferreira Salas Ruben Andres Silva Emilio Carlos Nelli 《Meccanica》2021,56(2):417-437
Meccanica - Fiber reinforced materials are used in assorted engineering application and for this reason, new additive manufacturing technologies have been developed for this type of materials. With... 相似文献
7.
Application of TiO2-nanotubes/PbO2 as an anode for the electrochemical elimination of Acid Red 1 dye
Santos José Eudes L. de Moura Dayanne Chianca da Silva Djalma Ribeiro Panizza Marco Martínez-Huitle Carlos A. 《Journal of Solid State Electrochemistry》2019,23(2):351-360
Journal of Solid State Electrochemistry - In this study, galvanostatic electrolysis, through the use of the platinum supported on Ti (Ti/Pt) and Ti/TiO2-nanotubes/PbO2 anodes, was conducted in an... 相似文献
8.
9.
Karen Beatriz Méndez-Rodríguez Nicté Figueroa-Vega César Arturo Ilizaliturri-Hernandez Mónica Cardona-Alvarado Jaime Antonio Borjas-García Carlos Kornhauser Juan Manuel Malacara Rogelio Flores-Ramírez Francisco Javier Pérez-Vázquez 《Biomedical chromatography : BMC》2020,34(12):e4956
Metabolomics is a potential tool for the discovery of new biomarkers in the early diagnosis of diseases. An ultra-fast gas chromatography system equipped to an electronic nose detector (FGC eNose) was used to identify the metabolomic profile of Volatile Organic Compounds (VOCs) in type 2 diabetes (T2D) urine from Mexican population. A cross-sectional, comparative, and clinical study with translational approach was performed. We recruited twenty T2D patients and twenty-one healthy subjects. Urine samples were taken and analyzed by FGC eNose. Eighty-eight compounds were identified through Kovats's indexes. A natural variation of 30% between the metabolites, expressed by study groups, was observed in Principal Component 1 and 2 with a significant difference (p < 0.001). The model, performed through a Canonical Analysis of Principal coordinated (CAP), allowed a correct classification of 84.6% between healthy and T2D patients, with a 15.4% error. The metabolites 2-propenal, 2-propanol, butane- 2,3-dione and 2-methylpropanal, were increased in patients with T2D, and they were strongly correlated with discrimination between clinically healthy people and T2D patients. This study identified metabolites in urine through FGC eNose that can be used as biomarkers in the identification of T2D patients. However, more studies are needed for its implementation in clinical practice. 相似文献
10.
Jerry Ray Dias 《Molecular physics》2020,118(12)
Cycloparaphenylene ([r]CPP) and cyclacene ([r]CA) series are models for short carbon nanotubes. It is shown that armchair edges in model cycloparaphenylenes possess greater aromaticity and cyclic conjugation than do zigzag edges in model cyclacenes. According to Aihara’s bond resonance energy (BRE) and Bosanac and Gutman energy effect (ef) measurements, cycloparaphenylenes are twice as aromatic as cyclacenes. The general solution of all eigenvalues of all members of the cycloparaphenylene series is given. The origin of the recurrence of some eigenvalues are determined. 相似文献