全文获取类型
收费全文 | 135232篇 |
免费 | 23447篇 |
国内免费 | 17556篇 |
专业分类
化学 | 95323篇 |
晶体学 | 1659篇 |
力学 | 8819篇 |
综合类 | 1242篇 |
数学 | 16710篇 |
物理学 | 52482篇 |
出版年
2024年 | 131篇 |
2023年 | 2488篇 |
2022年 | 3000篇 |
2021年 | 4198篇 |
2020年 | 5388篇 |
2019年 | 5277篇 |
2018年 | 4597篇 |
2017年 | 4572篇 |
2016年 | 6367篇 |
2015年 | 6483篇 |
2014年 | 7842篇 |
2013年 | 10184篇 |
2012年 | 12511篇 |
2011年 | 12915篇 |
2010年 | 9085篇 |
2009年 | 8851篇 |
2008年 | 9680篇 |
2007年 | 8532篇 |
2006年 | 7866篇 |
2005年 | 6621篇 |
2004年 | 5049篇 |
2003年 | 4126篇 |
2002年 | 3827篇 |
2001年 | 3218篇 |
2000年 | 2792篇 |
1999年 | 2733篇 |
1998年 | 2223篇 |
1997年 | 2115篇 |
1996年 | 2093篇 |
1995年 | 1768篇 |
1994年 | 1559篇 |
1993年 | 1304篇 |
1992年 | 1121篇 |
1991年 | 970篇 |
1990年 | 834篇 |
1989年 | 646篇 |
1988年 | 529篇 |
1987年 | 442篇 |
1986年 | 428篇 |
1985年 | 357篇 |
1984年 | 238篇 |
1983年 | 193篇 |
1982年 | 144篇 |
1981年 | 122篇 |
1980年 | 118篇 |
1979年 | 76篇 |
1978年 | 63篇 |
1977年 | 82篇 |
1976年 | 64篇 |
1973年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
992.
Wang Hong Cai Le He Shu-Hua Zheng Xiao-Bei Liu Yu-Xia Zhang Lan 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(6):2553-2559
Journal of Radioanalytical and Nuclear Chemistry - Prostate-specific membrane antigen (PSMA) is a biomarker for prostate cancer, which is commonly used in the development of diagnostic and... 相似文献
993.
Cheng Jiang Lisha Zhao Chuanwei Xin Yu Dong Jie Shen Zhongni Xia Dan Shou Gonghua Li 《Biomedical chromatography : BMC》2022,36(2):e5255
The allergic reaction (AR) of Chinese herbal injection (CHI) has become one of the most noticeable focuses of public health in China. However, it still remains a considerable controversy as to whether low-molecular-weight components in CHI have potential sensitization. In this study, the relationship between AR and low-molecular-weight component profile of Shenmai injection was explored by an interdisciplinary technology integrating real-world evidence and ultra-performance liquid chromatography–quadrupole time-of-flight mass spectroscopy (UPLC–Q-TOF-MS). The AR information of hospitalized patients was obtained by comprehensively analyzing real-world evidence from January 2015 to June 2019 at two Chinese hospitals. The UPLC–Q-TOF-MS was exploited to systematically investigate the low-molecular-weight component profile with 50–1500 m/z mass range, and 3725 MS1 peaks were detected. The optimized partial least squares discriminant analysis model was established to map the influence of low-molecular-weight components on AR. The results of this study showed that high levels of organic acids administered intravenously might be a potential risk factor for inducing AR. By using this method, Shenmai injection with high AR risk could be recognized precisely with 100% accuracy before clinical use. 相似文献
994.
Qingqing Ma Shanlin Xu Zhaodong Zhai Kai Wang Xueli Liu Prof. Haibin Xiao Prof. Shuping Zhuo Prof. Yuying Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(39):e202200828
Peroxynitrite (ONOO−) as a major reactive oxygen species plays important roles in cellular signal transduction and homeostatic regulation. Precise detection of ONOO− in biological systems is vital for exploring its physiological and pathological function. Among numerous detection methods, fluorescence imaging technology using fluorescent probes offers some advantages, including simple operation, high sensitivity and selectivity, as well as real-time and nondestructive detection. In particular, ratiometric fluorescent probes, in which the built-in calibration of the two emission bands prevents interference from the biological environment, have been extensively employed to monitor the fluctuation of bioactive species. In this review, we will discuss small-molecule ratiometric fluorescent probes for ONOO− in live cells or in vivo, which involves chemical structures, response mechanisms, and biological applications. Moreover, the challenges and future prospects of ONOO−-responsive ratiometric fluorescent probe are also proposed. 相似文献
995.
Song Rong-hao Gao Ming Geng Xue Ye Lin Zhang Ai-ying Feng Zeng-guo 《Journal of inclusion phenomena and macrocyclic chemistry》2022,102(1-2):99-108
Journal of Inclusion Phenomena and Macrocyclic Chemistry - Poly(ethylene glycol) diamine 1,1’-disubstituted ferrocene was utilized as a size-com-plementary site to synthesize lower coverage... 相似文献
996.
Xuan Liu Dr. Chengxi Huang Dr. Bo Ouyang Dr. Yongping Du Boyu Fu Zhengwei Du Qiang Ju Dr. Jingjing Ma Prof. Dr. Ang Li Prof. Dr. Erjun Kan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(43):e202201034
The CO2 reduction reaction (CRR) represents a promising route for the clean utilization of renewable resources. But mass-transfer limitations seriously hinder the forward step. Enhancing the surface hydrophobicity by using polymers has been proved to be one of the most efficient strategies. However, as macromolecular organics, polymers on the surface hinder the transfer of charge carriers from catalysts to reactants. Herein, we describe an in-situ surface fluorination strategy to enhance the surface hydrophobicity of TiO2 without a barrier layer of organics, thus facilitating the mass transfer of CO2 to catalysts and charge transfer. With less obstruction to charge transfer, a higher CO2, and lower H+ surface concentration, the photocatalytic CRR generation rate of methanol (CH3OH) is greatly enhanced to up to 247.15 μmol g−1 h−1. Furthermore, we investigated the overall defects; enhancing the surface hydrophobicity of catalysts provides a general and reliable method to improve the competitiveness of CRR. 相似文献
997.
Qiuyu He Lirong Cao Yiran Wei Prof. Gregory R. Dake 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(42):e202201328
The utility of 2-diphenylphosphoryloxy-1,3-dienes for the construction of substituted six-membered nitrogen heterocycles is presented. These dienes undergo boron trifluoride-promoted aza-Diels–Alder reactions when reacted with imines or related species formed in situ using aldehydes and amine derivatives. The stability of the dienes allows this three-component reaction to be carried out with no special precautions to eliminate water or air. Thirty-one examples of this process are presented. The usefulness of the enol phosphate functional group is highlighted in further reactions after the cycloaddition step to generate functionalized piperidenes or pyridines. 相似文献
998.
Jin Li Dr. Lei Wang Jinrong Li Yujie Shao Ziang Liu Dr. Guangzhe Li Prof. Dr. Engin U. Akkaya 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(34):e202200506
Naphthalene endoperoxides are known as convenient sources of singlet oxygen (O2, 1Δg), which is the major product of endoperoxide cycloreversion reaction. However, their potential as carriers of ground-state molecular oxygen (O2, 3Σg) similar to artificial oxygen carriers remains largely unexplored. This is due to the extreme reactivity and cytotoxic effects of the released singlet oxygen. We now report that a compound with a bimodular design, which incorporates an endoperoxide and an efficient physical quencher of singlet oxygen, 1,4-diazabicyclo[2.2.2]octane (DABCO), produces exclusively ground-state molecular oxygen. This result, coupled with the fact that oxygen release rates from endoperoxides are highly amenable to fine-tuning in a very broad range, and open to targeting by ligand attachment, raises the potential of these compounds far above any comparable chemical, or even biochemical sources. In cell culture experiments, we showed that the addition of the endoperoxide-quencher conjugate can enhance and sustain cell proliferation. 相似文献
999.
Yu Shimo Zhao Xinfu Zhang Jing Liu Sijia Yuan Zhipeng Liu Xiaochan Liu Benxue Yi Xibin 《Cellulose (London, England)》2022,29(12):6783-6796
Cellulose - High CO2 concentration in atmosphere causes serious environmental issues, and carbon capture and storage technologies have attracted attention as a means to reduce the atmospheric CO2... 相似文献
1000.
Xiao Yuanxiang Shen Guokang Zheng Weishi Fu Jiajia Fu Feiya Hu Xinyue Jin Ziyi Liu Xiangdong 《Cellulose (London, England)》2022,29(2):1003-1015
Cellulose - We report here a simple and effective method applying a combination of chitosan (Cs) and Cu(II) ion to fabricate antibacterial cotton fabric with a remarkable durability against... 相似文献