全文获取类型
收费全文 | 2881篇 |
免费 | 494篇 |
国内免费 | 390篇 |
专业分类
化学 | 2095篇 |
晶体学 | 30篇 |
力学 | 118篇 |
综合类 | 77篇 |
数学 | 358篇 |
物理学 | 1087篇 |
出版年
2024年 | 8篇 |
2023年 | 56篇 |
2022年 | 85篇 |
2021年 | 101篇 |
2020年 | 106篇 |
2019年 | 137篇 |
2018年 | 103篇 |
2017年 | 99篇 |
2016年 | 130篇 |
2015年 | 147篇 |
2014年 | 168篇 |
2013年 | 255篇 |
2012年 | 251篇 |
2011年 | 276篇 |
2010年 | 184篇 |
2009年 | 182篇 |
2008年 | 185篇 |
2007年 | 177篇 |
2006年 | 144篇 |
2005年 | 136篇 |
2004年 | 124篇 |
2003年 | 79篇 |
2002年 | 80篇 |
2001年 | 45篇 |
2000年 | 45篇 |
1999年 | 60篇 |
1998年 | 49篇 |
1997年 | 32篇 |
1996年 | 42篇 |
1995年 | 34篇 |
1994年 | 29篇 |
1993年 | 30篇 |
1992年 | 27篇 |
1991年 | 25篇 |
1990年 | 21篇 |
1989年 | 26篇 |
1988年 | 22篇 |
1987年 | 12篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1976年 | 4篇 |
1973年 | 4篇 |
1930年 | 1篇 |
排序方式: 共有3765条查询结果,搜索用时 0 毫秒
951.
Yang Qingqing Wang Wei Li Xingnian Li Qiang Xun Mengyuan Meng Li Tang Qiong Xu Jun 《Journal of Solid State Electrochemistry》2023,27(8):1955-1967
Journal of Solid State Electrochemistry - Two-dimensional transition metal carbides (MXenes) are widely used in the field of electrochemical energy storage due to their unique properties, but the... 相似文献
952.
Zhang Xinwei Feng Qiong Tong Shurong Eres Hakki 《Fuzzy Optimization and Decision Making》2022,21(4):605-647
Fuzzy Optimization and Decision Making - For several classes of decisions, the use of target-based decision analysis (TBDA) is more appropriate than utility analysis. Recent literature on TBDA... 相似文献
953.
Rui-Li Guo Xing-Long Zhang Xian-Pan Bu Meng-Yue Wang Bao-Yin Zhao Ya-Ru Gao Qiong Jia Prof. Yong-Qiang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(39):e202200981
A new class of electrophilic monofluoromethylselenolation reagents, Se-(fluoromethyl) benzenesulfonoselenoates, has been developed. They can be readily prepared from sodium benzenesulfinates, Se powder and ClCFH2 in one step under mild reaction conditions. Se-(fluoromethyl) benzenesulfonoselenoates are efficient electrophilic monofluoromethylselenolation reagents for a wide range of nucleophiles including indole, 6-azaindole, pyrrole, thiophene, electron-rich arene, aryl boronic acid and alkyne. The monofluoromethylselenolation approach features mild and environmentally friendly reaction conditions, good tolerance of various functional groups, and broad substrate scope. 相似文献
954.
Cui Shiqiang Zhang Yang Liu Changjun Lou Shanhao Zhang Yue Zhang Yumei Wang Huaping 《Cellulose (London, England)》2022,29(2):751-762
Cellulose - In order to research the multi-level structure of Lyocell fiber at different draw ratios and to reveal the limiting factors for preparing the high strength Lyocell fiber, the paper... 相似文献
955.
Ying Xuan Huiying Quan Prof. Zhurui Shen Chenxi Zhang Xiyuan Yang Prof. Lan-Lan Lou Prof. Shuangxi Liu Prof. Kai Yu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(10):2285-2292
It is known that the low lifetime of photogenerated carriers is the main drawback of elemental photocatalysts. Therefore, a facile and versatile one-step strategy to simultaneously achieve the oxygen covalent functionalization of amorphous red phosphorus (RP) and in situ modification of CdCO3 is reported. This strategy endows RP with enhanced charge carrier separation ability and photocatalytic activity by coupling band-gap engineering and heterojunction construction. The as-prepared nCdCO3/SO-RP (n=0.1, 0.25, 0.5, 1.0) composites exhibited excellent photocatalytic H2 evolution activity (up to 516.3 μmol g−1 h) from visible-light-driven water splitting (λ>400 nm), which is about 17.6 times higher than that of pristine RP. By experimental and theoretical investigations, the roles of surface oxygen covalent functionalization, that is, prolonging the lifetime of photogenerated carriers and inducing the negative shift of the conduction band potential, were studied in detail. Moreover, the charge transfer mechanism of these composites has also been proposed. In addition, these composites are stable and can be reused at least for three times without significant activity loss. This work may provide a good example of how to promote the activity of elemental photocatalysts by decorating their atomic structure. 相似文献
956.
A versatile and efficient telescoped reaction sequence for the synthesis of tetrahydroisoquinolines(THIQs)is reported that uses TiCl4 to promote cyclization of a benzylaminoacetal derivative and Et3SiH for reduction of the intermediate 4-hydroxy-THIQ.This method is complimentary to the classical Pomeranz-Fritsch and related reactions since it tolerates electron-withdrawing substituents and allows access to 8-substituted THIQs. 相似文献
957.
Tumor-Triggered Disassembly of a Multiple-Agent-Therapy Probe for Efficient Cellular Internalization
Juliang Yang Dr. Jun Dai Quan Wang Dr. Yong Cheng Jingjing Guo Prof. Zujin Zhao Prof. Yuning Hong Prof. Xiaoding Lou Prof. Fan Xia 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20585-20590
Integration of multiple agent therapy (MAT) into one probe is promising for improving therapeutic efficiency for cancer treatment. However, MAT probe, if entering the cell as a whole, may not be optimal for each therapeutic agent (with different physicochemical properties), to achieve their best performance, hindering strategy optimization. A peptide-conjugated-AIEgen (FC-PyTPA) is presented: upon loading with siRNA, it self-assembles into FCsiRNA-PyTPA. When approaching the region near tumor cells, FCsiRNA-PyTPA responds to extracellular MMP-2 and is cleaved into FCsiRNA and PyTPA. The former enters cells mainly by macropinocytosis and the latter is internalized into cells mainly through caveolae-mediated endocytosis. This two-part strategy greatly improves the internalization efficiency of each individual therapeutic agent. Inside the cell, self-assembly of nanofiber precursor F, gene interference of CsiRNA, and ROS production of PyTPA are activated to inhibit tumor growth. 相似文献
958.
Yanfang Liu Xiaoye Jin Shuyan Mei Qiong Lan Yating Fang Chao Liu Bofeng Zhu 《Electrophoresis》2020,41(23):2036-2046
Massively parallel sequencing (MPS) technology allows to simultaneously type multitudinous molecular genetic markers for many samples in one run with the feature of high detection resolution, and thereby arouses the increasing attention from forensic science. Herein, multiple allelic single nucleotide polymorphisms (multi-allelic SNPs) were screened for personal identification and parentage testing, and then were genotyped using MPS platform. Unrelated individuals of Chinese Mongolian and Kazakh groups were investigated to further estimate forensic effectiveness and applicability of these multi-allelic SNPs. The results of sequencing efficiency estimations and forensic genetic statistical parameters demonstrated that this MPS panel of multi-allelic SNPs was expected to be work for forensic applications. Subsequently, the exploration of population genetic variation patterns among the two investigated groups and other 26 reference populations revealed that these Chinese Mongolian and Kazakh groups had the similar population genetic patterns with the populations from East Asian, but European ancestral composition in the Kazakh group was higher than that in the Mongolian group. Currently, the present results were the preliminary research to scrutinize genetic information of these two ethnic minority groups employing multi-allelic SNPs. 相似文献
959.
960.