全文获取类型
收费全文 | 256075篇 |
免费 | 12648篇 |
国内免费 | 3035篇 |
专业分类
化学 | 162201篇 |
晶体学 | 3623篇 |
力学 | 9339篇 |
综合类 | 58篇 |
数学 | 26076篇 |
物理学 | 70461篇 |
出版年
2021年 | 2230篇 |
2020年 | 3510篇 |
2019年 | 5037篇 |
2018年 | 4513篇 |
2017年 | 4004篇 |
2016年 | 7940篇 |
2015年 | 6123篇 |
2014年 | 7603篇 |
2013年 | 13804篇 |
2012年 | 10451篇 |
2011年 | 11253篇 |
2010年 | 9297篇 |
2009年 | 9108篇 |
2008年 | 10906篇 |
2007年 | 10266篇 |
2006年 | 9400篇 |
2005年 | 8800篇 |
2004年 | 7737篇 |
2003年 | 7044篇 |
2002年 | 7561篇 |
2001年 | 7378篇 |
2000年 | 6064篇 |
1999年 | 3999篇 |
1998年 | 3205篇 |
1997年 | 3209篇 |
1996年 | 3011篇 |
1995年 | 2465篇 |
1994年 | 2535篇 |
1993年 | 2541篇 |
1992年 | 2695篇 |
1991年 | 2714篇 |
1990年 | 2636篇 |
1989年 | 2593篇 |
1988年 | 2494篇 |
1987年 | 2469篇 |
1986年 | 2400篇 |
1985年 | 3077篇 |
1984年 | 3208篇 |
1983年 | 2577篇 |
1982年 | 2836篇 |
1981年 | 2708篇 |
1980年 | 2509篇 |
1979年 | 2722篇 |
1978年 | 2833篇 |
1977年 | 2859篇 |
1976年 | 2834篇 |
1975年 | 2688篇 |
1974年 | 2665篇 |
1973年 | 2810篇 |
1972年 | 1875篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Sergio Ayala‐Mar Javier Donoso‐Quezada Roberto C. Gallo‐Villanueva Victor H. Perez‐Gonzalez Jos Gonzlez‐Valdez 《Electrophoresis》2019,40(23-24):3036-3049
Exosomes are nanovesicles secreted by most cellular types that carry important biochemical compounds throughout the body with different purposes, playing a preponderant role in cellular communication. Because of their structure, physicochemical properties and stability, recent studies are focusing in their use as nanocarriers for different therapeutic compounds for the treatment of different diseases ranging from cancer to Parkinson's disease. However, current bioseparation protocols and methodologies are selected based on the final exosome application or intended use and present both advantages and disadvantages when compared among them. In this context, this review aims to present the most important technologies available for exosome isolation while discussing their advantages and disadvantages and the possibilities of being combined with other strategies. This is critical since the development of novel exosome‐based therapeutic strategies will be constrained to the effectiveness and yield of the selected downstream purification methodologies for which a thorough understanding of the available technological resources is needed. 相似文献
83.
Mathematical Notes - It is proved that the lattice of all Fitting classes of finite groups is not distributive, and conditions under which Fitting classes satisfy the distributive and modular laws... 相似文献
84.
Isaeva A. I. Maikov E. Gibizova V. V. Petrova G. P. 《Journal of Applied Spectroscopy》2021,88(4):789-793
Journal of Applied Spectroscopy - Aqueous solutions of human hemoglobin have been studied by the multi-angle static light scattering method. The tendency of sickle-shaped erythrocytes to aggregate... 相似文献
85.
Stolpovskaya N. V. Kruzhilin A. A. Zorina A. V. Shikhaliev Kh. S. Ledeneva I. V. Kosheleva E. A. Vandyshev D. Yu. 《Russian Journal of Organic Chemistry》2019,55(9):1322-1328
Russian Journal of Organic Chemistry - A procedure has been proposed for the synthesis of a series of substituted N-(1,3-thiazol-2-yl)-pyrimidin-2-amines and N-(pyrimidin-2-yl)thioureas by... 相似文献
86.
Adly M. E. Gedawy E. M. El-Malah A. A. El-Telbany F. A. 《Russian Journal of Organic Chemistry》2019,55(8):1189-1196
Russian Journal of Organic Chemistry - Selenopheno[2,3-d]pyrimidine- and selenopheno[2,3-d][1,2,3]triazine-containing compounds were synthesized starting from... 相似文献
87.
Saleh Z. M. Nasser H. Özkol E. Günöven M. Abak K. Canli S. Bek A. Turan R. 《Journal of nanoparticle research》2015,17(10):1-12
Journal of Nanoparticle Research - Plasmonic interfaces consisting of silver nanoparticles of different sizes (50–100&;nbsp;nm) have been processed by the self-assembled dewetting... 相似文献
88.
E. V. Shadrina O. N. Malinkina T. G. Khonina A. B. Shipovskaya V. I. Fomina E. Yu. Larchenko N. A. Popova I. G. Zyryanova L. P. Larionov 《Russian Chemical Bulletin》2015,64(7):1633-1639
The biomimetic sol—gel synthesis of silicon—chitosan-containing glycerohydrogels was carried out using silicon tetraglycerolate as a precursor. It was found that chitosan accelerates gel formation in weakly acidic media. In more acidic media, the kinetics of the process changes according to the curve with a maximum, which can be attributed to different mechanisms of silanol condensation before and after the isoelectric point. The investigated silicon—chitosan-containing glycerohydrogels exhibit antibacterial, anti-inflammatory, and wound healing activity. The synthesized hybrid glycerohydrogels are promising materials for biomedical applications. 相似文献
89.
90.
Triazines are widely used in agriculture around the world as selective pre‐ and post‐emergence herbicides for the control of broad leaf and grassy weeds. With high toxicity and persistence, triazines can contaminate the environment and crops, so the development of rapid and sensitive methods for the determination of different triazines is necessary. Capillary electrophoresis comprises a group of techniques used to separate chemical mixtures. Analytical separation is based on different electrophoretic mobilities. This review focuses on the analysis of triazine herbicides with different modes of capillary electrophoresis, including capillary zone electrophoresis, micellar electrokinetic capillary electrophoresis, capillary electrochromatography and nonaqueous capillary electrophoresis. Determinations of triazines in various matrices such as surface water, groundwater, vegetables, soil and grains are emphasized. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献