全文获取类型
收费全文 | 20580篇 |
免费 | 3360篇 |
国内免费 | 2916篇 |
专业分类
化学 | 11796篇 |
晶体学 | 123篇 |
力学 | 979篇 |
综合类 | 158篇 |
数学 | 1595篇 |
物理学 | 5960篇 |
无线电 | 6245篇 |
出版年
2024年 | 100篇 |
2023年 | 586篇 |
2022年 | 653篇 |
2021年 | 854篇 |
2020年 | 839篇 |
2019年 | 787篇 |
2018年 | 642篇 |
2017年 | 621篇 |
2016年 | 899篇 |
2015年 | 921篇 |
2014年 | 1050篇 |
2013年 | 1523篇 |
2012年 | 1710篇 |
2011年 | 1760篇 |
2010年 | 1293篇 |
2009年 | 1308篇 |
2008年 | 1378篇 |
2007年 | 1238篇 |
2006年 | 1174篇 |
2005年 | 1006篇 |
2004年 | 701篇 |
2003年 | 668篇 |
2002年 | 672篇 |
2001年 | 591篇 |
2000年 | 531篇 |
1999年 | 531篇 |
1998年 | 436篇 |
1997年 | 362篇 |
1996年 | 325篇 |
1995年 | 294篇 |
1994年 | 261篇 |
1993年 | 211篇 |
1992年 | 214篇 |
1991年 | 177篇 |
1990年 | 135篇 |
1989年 | 89篇 |
1988年 | 74篇 |
1987年 | 62篇 |
1986年 | 43篇 |
1985年 | 45篇 |
1984年 | 23篇 |
1983年 | 21篇 |
1982年 | 23篇 |
1981年 | 12篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1957年 | 2篇 |
1943年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 58 毫秒
1.
Liu Wenbin Huang Yiwei Huang Guolin Fan Lijiao Xie Yuming Shi Jeffery 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2055-2068
Journal of Radioanalytical and Nuclear Chemistry - Eco-friendly and low-cost composite, amidoxime-functionalized microcrystalline cellulose/mesoporous silica (MCC/MS-AO), were synthesized by... 相似文献
2.
Journal of Optimization Theory and Applications - We distinguish two kinds of piecewise linear functions and provide an interesting representation for a piecewise linear function between two normed... 相似文献
3.
Simultaneous determination of cinnamaldehyde and its metabolite in rat tissues by gas chromatography–mass spectrometry
下载免费PDF全文
![点击此处可从《Biomedical chromatography : BMC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hang Zhao Qian Yang Yanhua Xie Jiyuan Sun Honghai Tu Wei Cao Siwang Wang 《Biomedical chromatography : BMC》2015,29(2):182-187
Cinnamaldehyde (CA), an active ingredient isolated from the traditional Chinese medicine Cortex Cinnamomi, has a wide range of bioactivities. To clarify the distribution characteristics of CA, a selective and sensitive method utilizing gas chromatography–mass spetrometry was initially developed for simultaneously determining the concentration of CA and its metabolite cinnamyl alcohol in rat tissues. Selected ion masses of m/z 131, 105 and 92 were chosen, and separation of the analytes was performed on a DB‐5 ms (30 m × 0.25 mm, 0.25 µm, thickness) capillary column by gas chromatography–mass spectrometry. The calibration curves demonstrated good linearity and reproducibility over the range of 20–2000 and 20–4000 ng/mL for various tissue samples. Recoveries ranged from 86.8 to 107.5%, while intra‐ and interday relative standard deviations were all <11.3%. The analysis method was successfully applied in tissue distribution studies for CA and cinnamyl alcohol. As CA and cinnamyl alcohol may inter‐convert to one another, simultaneous determination of both analytes provides a comparative and accurate data for tissue study. The concentrations of CA and cinnamyl alcohol remaining in spleen were the highest among the main organs, including heart, liver, spleen, lung, kidney and brain. In addition, there was no long‐term accumulation of CA in rat tissues. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
4.
Zhen Xi 《中国科学:化学(英文版)》2015,(3):434-435
Redox-based post-translational modification of protein thiols has become an attractive strategy in cellular homeostasis and cell signaling.Due to the reductive end of the redox buffer network,the vicinal dithiol-containing proteins(VDPs)maintains an appropriate oxidation-reduction state of proteins through the reversible transformation from vicinal dithiols to disulfide,which is responsible for a variety of 相似文献
5.
6.
Xianjin Li Tianyu Li Pengcheng Xu Congxin Xie Yunhe Zhang Xianfeng Li 《Advanced functional materials》2021,31(22):2100133
Bromine-based flow batteries (Br-FBs) are considered one of the most promising energy storage systems due to their features of high energy density and low cost. However, they generally suffer from uncontrolled diffusion of corrosive bromine particularly at high temperatures. That is because the interaction between polybromide anions and the commonly used complexing agent (N–methyl–N–ethyl–pyrrolidinium bromide [MEP]) decreases with increasing temperatures, which causes serious self-discharge and capacity fade. Herein, a novel bromine complexing agent, 1–ethyl–2–methyl–pyridinium bromide (BCA), is introduced in Br-FBs to solve the above problems. It is proven that BCA can combine with polybromide anions very well even at a high temperature of 60 °C. Moreover, the BCA contributes to decreasing the electrochemical polarization of Br−/Br2 couple, which in turn improves their power density. As a result, a zinc–bromine flow battery with BCA as the complexing agent can achieve a high energy efficiency of 84% at 40 mA cm−2, even at high temperature of 60 °C and it can stably run for more than 400 cycles without obvious performance decay. This paper provides an effective complexing agent to enable a wide temperature range Br-FB. 相似文献
7.
8.
9.
10.
Jia Yang Xingang Li Wenjun Li Xin Xi Qian Du Feng Pan Songqing Liu 《Biomedical chromatography : BMC》2020,34(8):e4857
Because of its unpredictable side effects and efficacy, the anticancer drug docetaxel (DTX) requires improved characterisation of its pharmacokinetic profiles through population pharmacokinetic studies. A sensitive and rugged LC–MS/MS method for the detection of DTX in human plasma was developed and optimised using paclitaxel as an internal standard (IS). The plasma samples underwent rapid extraction using hybrid solid-phase extraction-protein precipitation. The analyte and IS were separated with an isocratic system on a Zorbax Eclipse Plus C18 column using water containing 0.05% acetic acid along with 20 μM of sodium acetate and methanol (30/70, v/v) as the mobile phase. Quantification was performed using a triple quadrupole mass spectrometer through multiple reaction monitoring in positive mode, using the m/z 830.3 → 548.8 and m/z 876.3 → 307.7 transitions for DTX and paclitaxel, respectively. The range of the calibration curve was 1–500 ng/mL for DTX, and the linear correlation coefficient was >0.99. The accuracies ranged from −4.6 to 4.2%, and the precision was no higher than 7.0% for the analytes. No significant matrix effect was observed. Both DTX and the IS showed considerable recovery. This method was finally applied to the establishment of a population pharmacokinetic model to optimise the clinical use of DTX. 相似文献