全文获取类型
收费全文 | 271篇 |
免费 | 7篇 |
国内免费 | 15篇 |
专业分类
化学 | 142篇 |
晶体学 | 1篇 |
力学 | 71篇 |
综合类 | 7篇 |
数学 | 14篇 |
物理学 | 58篇 |
出版年
2023年 | 3篇 |
2022年 | 4篇 |
2021年 | 5篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 12篇 |
2014年 | 5篇 |
2013年 | 7篇 |
2012年 | 8篇 |
2011年 | 12篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 14篇 |
2005年 | 21篇 |
2004年 | 15篇 |
2003年 | 24篇 |
2002年 | 27篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1957年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有293条查询结果,搜索用时 15 毫秒
291.
Su-Nv Tang Jian-Bo Yang Shuai E Shuo He Jia-Xin Li Kai-Quan Yu Min Zhang Qing Li Lei Sun Hui Li 《Molecules (Basel, Switzerland)》2022,27(13)
Cephalanthus tetrandrus (Roxb.) Ridsd. et Badh. F. (CT) belongs to the Rubiaceae family. Its dried leaves are widely used in traditional Chinese medicine to treat enteritis, dysentery, toothache, furuncles, swelling, traumatic injury, fracture, bleeding, and scalding. In order to further clarify the unknown chemical composition of CT, a rapid strategy based on UHPLC-Q-exactive orbitrap was established for this analysis using a Thermo Scientific Hypersil GOLDTM aQ (100 mm × 2.1 mm, 1.9 µm) chromatographic column. The mobile phase was 0.1% formic acid water–acetonitrile, with a flow rate of 0.3 mL/min and injection volume of 2 µL; for mass spectrometry, an ESI ion source in positive and negative ion monitoring modes was adopted. A total of 135 chemicals comprising 67 chlorogenic acid derivatives, 48 flavonoids, and 20 anthocyanin derivatives were identified by comparing the mass spectrum information with standard substances, public databases, and the literature, which were all discovered for the first time in this plant. This result broadly expands the chemical composition of CT, which will contribute to understanding of its effectiveness and enable quality control. 相似文献
292.
Jing Deng Lifang Ye Guanghao Xu Zhiguo Ma Hui Cao Ying Zhang Menghua Wu 《Journal of separation science》2023,46(9):2300063
Artemisiae Argyi Folium (Aiye in Chinese) has been widely used since ancient times. In the Lingnan region (Southern China), the leaf of Artemisia verlotorum Lamotte, which is named Hongjiaoai (HJA) because the roots are red (Hongjiao means red foot in Chinese), has been used as a local substitute for Artemisiae Argyi Folium. The plant has a long medicinal and edible history that can be traced to the Jin Dynasty. However, there is no systematic and reliable method to control the quality of Artemisiae Verlotori Folium. In this study, a comprehensive method involving high-performance liquid chromatography coupled with diode array detection and quadrupole-time-of-flight high-definition mass spectrometry was established to identify and quantify eight constituents (including organic acids and flavonoids) in Artemisiae Verlotori Folium and Artemisiae Argyi Folium as well as high-performance liquid chromatography fingerprints of the two varieties. Moreover, dissimilarities of chemical compositions among the two varieties were further investigated by orthogonal partial least squares discrimination analysis and cluster analysis. This research not only explored the similarities and differences between Artemisiae Verlotori Folium and Artemisiae Argyi Folium in eight components but also provided a qualitative and quantitative analytical method that quickly, accurately, and comprehensively assesses the quality of Artemisiae Verlotori Folium. 相似文献
293.
As a main source for the recognition and identification of lead compounds, traditional Chinese medicine plays a pivotal role in preventing diseases for years. However, screening bioactive compounds from traditional Chinese medicine remains challenging because of the complexity of the systems and the occurrence of the synergic effect of the compounds. The infructescence of Platycarya strobilacea Sieb. et Zucc is prescribed for allergic rhinitis treatment with unknown bioactive compounds and unclear mechanisms. Herein, we immobilized the β2-adrenoceptor and muscarine-3 acetylcholine receptor onto the silica gel surface to prepare the stationary phase in a covalent bond through one step. The feasibility of the columns was investigated by the chromatographic method. Ellagic acid and catechin were identified as the bioactive compounds targeting the receptors. The binding constants of ellagic acid were calculated to be (1.56 ± 0.23)×107 M−1 for muscarine-3 acetylcholine receptor and (2.93 ± 0.15)×107 M−1 for β2-adrenoceptor by frontal analysis. While catechin can bind with muscarine-3 acetylcholine receptor with an affinity of (3.21 ± 0.05)×105 M−1. Hydrogen bonds and van der Waals’ force were the main driving forces for the two compounds with the receptors. The established method provides an alternative for multi-target bioactive compound screening in complex matrices. 相似文献