全文获取类型
收费全文 | 66605篇 |
免费 | 14636篇 |
国内免费 | 5782篇 |
专业分类
化学 | 62472篇 |
晶体学 | 671篇 |
力学 | 2798篇 |
综合类 | 328篇 |
数学 | 5967篇 |
物理学 | 14787篇 |
出版年
2024年 | 89篇 |
2023年 | 695篇 |
2022年 | 873篇 |
2021年 | 1266篇 |
2020年 | 2467篇 |
2019年 | 3711篇 |
2018年 | 2066篇 |
2017年 | 1667篇 |
2016年 | 4767篇 |
2015年 | 4958篇 |
2014年 | 5138篇 |
2013年 | 6376篇 |
2012年 | 5693篇 |
2011年 | 5158篇 |
2010年 | 4838篇 |
2009年 | 4728篇 |
2008年 | 4410篇 |
2007年 | 3602篇 |
2006年 | 3242篇 |
2005年 | 3039篇 |
2004年 | 2663篇 |
2003年 | 2331篇 |
2002年 | 2969篇 |
2001年 | 2149篇 |
2000年 | 2023篇 |
1999年 | 1112篇 |
1998年 | 645篇 |
1997年 | 528篇 |
1996年 | 555篇 |
1995年 | 482篇 |
1994年 | 439篇 |
1993年 | 375篇 |
1992年 | 360篇 |
1991年 | 322篇 |
1990年 | 278篇 |
1989年 | 216篇 |
1988年 | 139篇 |
1987年 | 134篇 |
1986年 | 106篇 |
1985年 | 107篇 |
1984年 | 63篇 |
1983年 | 63篇 |
1982年 | 52篇 |
1981年 | 28篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1975年 | 9篇 |
1957年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
Jia Tian-Cong Guo Jin-Tao Wang Zhen Zhu Xiao-Shan Zhang Qian-Xin Chen Ping Yao Kun Lv Wen-Ying Liu Guo-Guang 《Journal of Radioanalytical and Nuclear Chemistry》2019,321(3):823-829
Journal of Radioanalytical and Nuclear Chemistry - In the present work the final products of coumarin radiation chemical transformation are investigated by chromatography. During radiolysis of... 相似文献
32.
33.
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
34.
Ding Q. Yao M. Wu Sh. Zeng M. Xue N. Wu D. Xu J. 《Journal of Applied Spectroscopy》2022,89(4):712-718
Journal of Applied Spectroscopy - Based on partial least squares (PLS) analysis, the effects of different smoothing points and different preprocessing methods on the accuracy and precision of the... 相似文献
35.
Luo Dajuan Liu Bingqian Gao Rong Su Lixia Su Yonghuan 《Journal of Solid State Electrochemistry》2022,26(3):749-759
Journal of Solid State Electrochemistry - Cortisol, a steroid hormone, has been confirmed as a kind of biomarker that reflects the stress response of psychobiology and related adverse health... 相似文献
36.
37.
38.
39.
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
40.
Xiaoshuang Luo Xinxian Qin Zhengyi Liu Dan Chen Weiwei Yu Kankan Zhang Deyu Hu 《Biomedical chromatography : BMC》2020,34(1):e4694
A simple and rapid analytical method for the detection of trifloxystrobin, trifloxystrobin acid and tebuconazole in soil, brown rice, paddy plants and rice hulls was established and validated by liquid chromatography with tandem mass spectrometry. Acceptable linearity (R2 > 0.99), accuracy (average recoveries of 74.3–108.5%) and precision (intra- and inter-day relative standard deviations of 0.9–8.8%) were obtained using the developed determination approach. In the field trial, the half-lives of trifloxystrobin and tebuconazole in paddy plants were 5.7–8.3 days in three locations throughout China, and the terminal residue concentrations of trifloxystrobin and tebuconazole were <100 and 500 μg/kg (maximum residue limits set by China), respectively, at harvest, which indicated that, based on the recommended application procedure, trifloxystrobin and tebuconazole are safe for use on rice. The risk assessment results demonstrated that, owing to risk quotient values of both fungicides being <100%, the potential risk of trifloxystrobin and tebuconazole on rice was acceptable for Chinese consumers. These data could provide supporting information for the proper use and safety evaluation of trifloxystrobin and tebuconazole in rice. 相似文献