全文获取类型
收费全文 | 3048篇 |
免费 | 131篇 |
国内免费 | 25篇 |
专业分类
化学 | 2156篇 |
晶体学 | 19篇 |
力学 | 122篇 |
综合类 | 1篇 |
数学 | 410篇 |
物理学 | 496篇 |
出版年
2024年 | 14篇 |
2023年 | 28篇 |
2022年 | 207篇 |
2021年 | 196篇 |
2020年 | 127篇 |
2019年 | 103篇 |
2018年 | 113篇 |
2017年 | 96篇 |
2016年 | 161篇 |
2015年 | 112篇 |
2014年 | 111篇 |
2013年 | 248篇 |
2012年 | 181篇 |
2011年 | 197篇 |
2010年 | 124篇 |
2009年 | 115篇 |
2008年 | 132篇 |
2007年 | 124篇 |
2006年 | 96篇 |
2005年 | 95篇 |
2004年 | 75篇 |
2003年 | 80篇 |
2002年 | 52篇 |
2001年 | 38篇 |
2000年 | 32篇 |
1999年 | 21篇 |
1998年 | 16篇 |
1997年 | 8篇 |
1996年 | 24篇 |
1995年 | 13篇 |
1994年 | 12篇 |
1993年 | 24篇 |
1992年 | 21篇 |
1991年 | 19篇 |
1990年 | 17篇 |
1989年 | 10篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 15篇 |
1980年 | 11篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 10篇 |
1973年 | 4篇 |
排序方式: 共有3204条查询结果,搜索用时 15 毫秒
101.
102.
Santa Islam Syed Shaheen Shah Prof. Shamsun Naher Dr. Muhammad Ali Ehsan Dr. Md. Abdul Aziz Dr. A. J. Saleh Ahammad 《化学:亚洲杂志》2021,16(22):3516-3543
Dopamine (DA) is an important neurotransmitter, which is created and released from the central nervous system. It plays a crucial role in human activities, like cognition, emotions, and response to anything. Maladjustment of DA in human blood serum results in different neural diseases, like Parkinson's and Schizophrenia. Consequently, researchers have started working on DA detection in blood serum, which is undoubtedly a hot research area. Electrochemical sensing techniques are more promising to detect DA in real samples. However, utilizing conventional electrodes for selective determination of DA encounters numerous problems due to the coexistence of other materials, such as uric acid and ascorbic acid, which have an oxidation potential close to DA. To overcome such problems, researchers have put their focus on the modification of bare electrodes. The aim of this review is to present recent advances in modifications of most used bare electrodes with carbonaceous materials, especially graphene, its derivatives, and carbon nanotubes, for electrochemical detection of DA. A brief discussion about the mechanistic phenomena at the electrode interface has also been included in this review. 相似文献
103.
Basma H. Amin Mohamed I. Abou-Dobara Mostafa A. Diab Essam A. Gomaa Mohammed A. El-Mogazy Adel Z. El-Sonbati Mohamed S. EL-Ghareib Mostafa A. Hussien Hanaa M. Salama 《应用有机金属化学》2020,34(8):e5689
A novel series of mixed-ligand complexes of 5,5′-{(1E,1E′)-1,4-phenelynebis(diazene-2,1-diyl)}bis(quinolin-8-ol) (H2L1) as a primary ligand and 4-aminoantipyrine(L2) as a secondary ligand with Mn(II) ion were prepared using two general formulae: [Mn2(H2L1)2(L2)2X4].4Cl (X = OH2( 1 ), ONO2−( 2 ), Cl=nil; OAc( 3 ), Cl = nil) and [Mn2(H2L1)(L2)2(O2SO2)2]( 4 ). Free ligands and their complexes were characterized. Electronic absorption spectra of the mixed-ligand complexes indicate a distorted octahedral geometry around the central metal ion, and the anions X− are in the axial positions for all compounds. The ligands behave in a neutral bidentate manner, through nitrogen atoms and oxygen atoms of the carbonyl group (L2), whereas H2L1 coordinated through nitrogen and OH groups as a neutral bidentate ligand. All complexes do not contain coordinated water molecules, but complex ( 1 ) contains four water molecules. The water molecules are removed in a single step. The complexes exhibited magnetic susceptibility corresponding to five unpaired electrons. The antimicrobial activity of the Mn(II) mixed-ligand complexes ( 1–4 ) against two gram-positive bacteria, three local gram-negative bacteria, and three fungi species was tested. Mn(II) mixed-ligand complex ( 2 ) exhibited significant antibacterial activity against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas sp. Mixed-ligand complex ( 2 ) exhibited a high potential cytotoxicity against the growth of human lung cancer cells. 相似文献
104.
105.
Samira Benmouloud Rachid Echarghaoui Si. Mohammed Sbaï 《Journal of Mathematical Analysis and Applications》2012,396(1):375-385
In this paper, by using the Lusternik–Schnirelmann category, we obtain a multiplicity result for a quasilinear elliptic system with both concave and convex nonlinearities and critical growth terms in bounded domains. 相似文献
106.
Dr. Mohammed Tariq Dr. Daniel Salavera Prof. Alberto Coronas Prof. Luis P. N. Rebelo Prof. Jose N. Canongia Lopes 《Chemphyschem》2013,14(9):1956-1968
In this work the applicability of four of the most commonly used viscosity mixing rules to [ionic liquid (IL)+molecular solvent (MS)] systems is assessed. More than one hundred (IL+MS) binary mixtures were selected from the literature to test the viscosity mixing rules proposed by 1) Hind (Hi), 2) Grunberg and Nissan (G–N), 3) Herric (He) and 4) Katti and Chaudhri (K–C). The analyses were performed by estimating the average (absolute or relative) deviations, AADs and ARDs, between the available experimental data and the predicted ideal mixture viscosity values obtained by means of each rule. The interaction terms corresponding to the adjustable parameters inherent to each rule were also calculated and their trends discussed. 相似文献
107.
Saleh Ashrafi Okhtay Jahanbakhsh Davood Alizadeh Behrooz Salehpour 《Central European Journal of Physics》2013,11(5):560-567
Compton scattering tomography is widely used in numerous applications such as biomedical imaging, nondestructive industrial testing and environmental survey, etc. This paper proposes the use of the genetic algorithm (GA), which utilizes bio-inspired mathematical models, to construct an image of the insides of a test object via the scattered photons, from a voxel within the object. A NaI(Tl) scintillation detector and a 185 MBq 137Cs gamma ray source were used in the experimental measurements. The obtained results show that the proposed GA based method performs well in constructing images of objects. 相似文献
108.
109.
110.
Ajaj Rahaf Shubyar Nasser Alashban Yazeed El-Sayed Samar Salah Tamar Al Yafei Mohammed A. Salem 《Journal of Radioanalytical and Nuclear Chemistry》2021,330(3):923-928
Journal of Radioanalytical and Nuclear Chemistry - Groundwater is the most valuable resource in arid regions, such as UAE. Estimations of natural radionuclide concentrations are important to... 相似文献