全文获取类型
收费全文 | 1618篇 |
免费 | 95篇 |
国内免费 | 15篇 |
专业分类
化学 | 861篇 |
晶体学 | 7篇 |
力学 | 93篇 |
数学 | 240篇 |
物理学 | 328篇 |
无线电 | 199篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 39篇 |
2021年 | 72篇 |
2020年 | 89篇 |
2019年 | 78篇 |
2018年 | 83篇 |
2017年 | 77篇 |
2016年 | 101篇 |
2015年 | 81篇 |
2014年 | 87篇 |
2013年 | 148篇 |
2012年 | 132篇 |
2011年 | 133篇 |
2010年 | 74篇 |
2009年 | 63篇 |
2008年 | 62篇 |
2007年 | 41篇 |
2006年 | 40篇 |
2005年 | 38篇 |
2004年 | 37篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 14篇 |
2000年 | 11篇 |
1999年 | 15篇 |
1998年 | 6篇 |
1997年 | 10篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 14篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 10篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1980年 | 4篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1967年 | 2篇 |
1956年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有1728条查询结果,搜索用时 343 毫秒
1.
Inas A. Abdallah Sherin F. Hammad Alaa Bedair Mohamed A. Abdelaziz Neil D. Danielson Ahmed H. Elshafeey Fotouh R. Mansour 《Biomedical chromatography : BMC》2022,36(6):e5365
Favipiravir is a potential antiviral medication that has been recently licensed for Covid-19 treatment. In this work, a gadolinium-based magnetic ionic liquid was prepared and used as an extractant in dispersive liquid–liquid microextraction (DLLME) of favipiravir in human plasma. The high enriching ability of DLLME allowed the determination of favipiravir in real samples using HPLC/UV with sufficient sensitivity. The effects of several variables on extraction efficiency were investigated, including type of extractant, amount of extractant, type of disperser and disperser volume. The maximum enrichment was attained using 50 mg of the Gd-magnetic ionic liquid (MIL) and 150 μl of tetrahydrofuran. The Gd-based MIL could form a supramolecular assembly in the presence of tetrahydrofuran, which enhanced the extraction efficiency of favipiravir. The developed method was validated according to US Food and Drug Administration bioanalytical method validation guidelines. The coefficient of determination was 0.9999, for a linear concentration range of 25 to 1.0 × 105 ng/ml. The percentage recovery (accuracy) varied from 99.83 to 104.2%, with RSD values (precision) ranging from 4.07 to 11.84%. The total extraction time was about 12 min and the HPLC analysis time was 5 min. The method was simple, selective and sensitive for the determination of favipiravir in real human plasma. 相似文献
2.
Kherroubi Seddik Benkahla Youb Khaled Labsi Nabila Ragui Karim Bensaci Abdelghani Boutra Abdelkader Ouyahia Seif-Eddine Benzema Mahdi 《Journal of Thermal Analysis and Calorimetry》2021,144(3):623-646
Journal of Thermal Analysis and Calorimetry - Through this paper, three-dimensional fluid flow and heat transfer of Al2O3 nanofluid within ventilated enclosures was taken into consideration.... 相似文献
3.
4.
Malekahmadi Omid Kalantar Mahdi Nouri-Khezrabad Mohsen 《Journal of Thermal Analysis and Calorimetry》2021,144(6):2109-2126
Journal of Thermal Analysis and Calorimetry - The hydroxyapatite is one of the biocompatible and insulating bioceramics, while the carbon nanotube has a high thermal conductivity potential. This... 相似文献
5.
We consider the rate of convergence for a class of perturbed hemivariational inequalities in reflexive Banach Spaces. Our results can be viewed as an extension and refinement of some previous known results in this area. 相似文献
6.
Yang Wang Mansour N. Salem A. Brennan K.F. Ruden P.P. 《Quantum Electronics, IEEE Journal of》1992,28(2):507-513
The authors present a theoretical analysis of a possible avalanching photodetector (APD)-based on II-VI compound semiconductors. Each unit cell is composed of a HgTe layer, or a similar semimetal, sandwiched between two layers of CdTe and HgCdTe or similar semiconducting materials. The barrier layers are graded so that the leading barrier height is just high enough to eliminate the thermionic emission dark current out of the well. The use of a semimetal within the well has a distinct advantage over a semiconductor, which is that the ionization process is essentially an interband mechanism since the confined carriers within the well lie within the overlapping conduction and valence bands. As a result, the concentration of target carriers is virtually inexhaustible as in a conventional interband device 相似文献
7.
8.
9.
Dendritic cellls (DCs) comprise an essential component of the immune system. These cells, as antigen presenting cells (APCs)
to na?ve T cells, are crucial in the initiation of antigen specific immune responses. In the past years, several DC subsets
have been identified in different organs which exert different effects in order to elicit adaptive immune responses. Thus,
identification of such DC subsets has led to a better understanding of their distribution and function in the body. In this
review, several key properties of the immunobiology, immunopathogenesis and vaccine strategies using DCs will be discussed. 相似文献
10.