全文获取类型
收费全文 | 27951篇 |
免费 | 4644篇 |
国内免费 | 3798篇 |
专业分类
化学 | 20218篇 |
晶体学 | 424篇 |
力学 | 1889篇 |
综合类 | 320篇 |
数学 | 3559篇 |
物理学 | 9983篇 |
出版年
2023年 | 518篇 |
2022年 | 608篇 |
2021年 | 798篇 |
2020年 | 1111篇 |
2019年 | 1115篇 |
2018年 | 909篇 |
2017年 | 930篇 |
2016年 | 1243篇 |
2015年 | 1379篇 |
2014年 | 1616篇 |
2013年 | 2078篇 |
2012年 | 2649篇 |
2011年 | 2650篇 |
2010年 | 1941篇 |
2009年 | 1794篇 |
2008年 | 1999篇 |
2007年 | 1774篇 |
2006年 | 1676篇 |
2005年 | 1414篇 |
2004年 | 1069篇 |
2003年 | 884篇 |
2002年 | 821篇 |
2001年 | 688篇 |
2000年 | 566篇 |
1999年 | 510篇 |
1998年 | 373篇 |
1997年 | 352篇 |
1996年 | 355篇 |
1995年 | 312篇 |
1994年 | 257篇 |
1993年 | 218篇 |
1992年 | 211篇 |
1991年 | 210篇 |
1990年 | 164篇 |
1989年 | 149篇 |
1988年 | 122篇 |
1987年 | 81篇 |
1986年 | 105篇 |
1985年 | 75篇 |
1984年 | 67篇 |
1983年 | 61篇 |
1982年 | 46篇 |
1981年 | 39篇 |
1980年 | 45篇 |
1979年 | 34篇 |
1978年 | 44篇 |
1977年 | 33篇 |
1976年 | 30篇 |
1974年 | 27篇 |
1973年 | 34篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Li Zhisheng Jiang Haokai Cheng Yanying Gao Yunji Chen Longfei Zhang Yuchun Li Tao Xing Shaoshuai 《Journal of Thermal Analysis and Calorimetry》2022,147(21):12139-12154
Journal of Thermal Analysis and Calorimetry - Few investigations have focused on the influence of longitudinal fire source location on the temperature profile of smoke induced by fire in a tunnel... 相似文献
32.
Zhao Yi Liang Kaitai Zhao Yanqi Yang Bo Ming Yang Panaousis Emmanouil 《Designs, Codes and Cryptography》2022,90(4):921-937
Designs, Codes and Cryptography - An algorithm substitution attack (ASA) can undermine the security of cryptographic primitives by subverting the original implementation. An ASA succeeds when it... 相似文献
33.
Yang Gang Wang Yanhui Yang Xueying Pan Yuelong Liu Yu Cheng Jianfeng Jiang Qiao Tuo Xianguo 《Journal of Radioanalytical and Nuclear Chemistry》2022,331(5):2135-2145
Journal of Radioanalytical and Nuclear Chemistry - The preparation of C30 concrete for a cavernous waste repository under construction in China and its Cs(I) adsorption performance were... 相似文献
34.
Kai Cheng Xiao-Shuai Zhang Jie An Cheng Li Ruo-Yun Zhang Run Ye Prof. Dr. Bang-Jiao Ye Prof. Dr. Bo Liu Prof. Dr. Yuan-Di Zhao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(31):7553-7560
Given their superior penetration depths, photosensitizers with longer absorption wavelengths present broader application prospects in photodynamic therapy (PDT). Herein, Ag2S quantum dots were discovered, for the first time, to be capable of killing tumor cells through the photodynamic route by near-infrared light irradiation, which means relatively less excitation of the probe compared with traditional photosensitizers absorbing short wavelengths. On modification with polydopamine (PDA), PDA-Ag2S was obtained, which showed outstanding capacity for inducing reactive oxygen species (increased by 1.69 times). With the addition of PDA, Ag2S had more opportunities to react with surrounding O2, which was demonstrated by typical triplet electron spin resonance (ESR) analysis. Furthermore, the PDT effects of Ag2S and PDA-Ag2S achieved at longer wavelengths were almost identical to the effects produced at 660 nm, which was proved by studies in vitro. PDA-Ag2S showed distinctly better therapeutic effects than Ag2S in experiments in vivo, which further validated the enhanced regulatory effect of PDA. Altogether, a new photosensitizer with longer absorption wavelength was developed by using the hitherto-unexplored photodynamic function of Ag2S quantum dots, which extended and enhanced the regulatory effect originating from PDA. 相似文献
35.
Yihan Zhang Cui Bo Yanhao Fan Rui An Long Chen Yifan Zhang Yiqun Jia Xinhong Wang 《Biomedical chromatography : BMC》2019,33(3)
A quick and effective workflow based on ultra‐performance liquid chromatography coupled with electron spray ionization and LTQ‐Orbitrap mass spectrometry (UPLC‐LTQ‐Orbitrap MS) was established for compositional analysis and screening of the characteristic compounds of three species of Atractylodes rhizome for quality evaluation. This technique was employed to determine the seven main components in Atractylodes rhizome samples. Ultimately, 78 constituents were identified; of these, seven characteristic compounds were selected for species discrimination, comprising atractylodin (63), atractylenolide I (43), atractylenolide II (49), atractylenolide III (53), atractylon (69), methyl‐atractylenolide II (54) and (4E,6E,12E)‐tetradecadecatriene‐8,10‐diyne‐1,3‐diacetate (59). The seven main compounds, including six characteristic compounds, were simultaneously determined in 29 batches of Atractylodes rhizome samples. Thus, the method validation showed acceptable results. Quantitative analysis showed significantly different contents of the seven main components among the three species of Atractylodes rhizome, which indicates possible distinctions in the pharmacological effects. This established method can simultaneously provide qualitative and quantitative results for compositional characterization of Atractylodes rhizomes and for quality control. 相似文献
36.
Journal of Solid State Electrochemistry - The effects of chemisorbed sulfate on the spatiotemporal dynamics of Na2S in strongly alkaline solutions were investigated via electrochemical measurements... 相似文献
37.
Li Jinfeng Li Chenguang Sun Lingjie Zhang Xiaotao Cheng Shanshan Hu Wenping 《中国科学:化学(英文版)》2019,62(7):916-920
Science China Chemistry - As bifunctional materials, phenanthrene derivatives 2,7-diphenylphenanthrene and 2,7-di(styryl)phenanthrene (DPPa and DSPa) were designed and studied. Both materials show... 相似文献
38.
39.
The current response for the parameter change of a mesoscopic system is a practical issue for future's circuit design. Nowadays most considered cases are various types of bias modulation, while the effect of change of conductor Hamiltonian is seldom addressed. In this paper, we investigate the response of ballistic transport induced by a sudden change of the conductor Hamiltonian. We formulize the terminal current in language of non-equilibrium Green's function. Our method is applied to one-dimensional tight-binding chains and we find that the terminal current has a delay to the Hamiltonian change. The amount of delay is not determined by the velocity of incident electrons in the bias window, but depends on the tight-binding hopping energy γ. The delay of current response at the detecting point away from where the Hamiltonian changes is , where C is a constant independent of the system. 相似文献
40.