全文获取类型
收费全文 | 1945篇 |
免费 | 90篇 |
国内免费 | 9篇 |
专业分类
化学 | 1549篇 |
晶体学 | 21篇 |
力学 | 32篇 |
数学 | 142篇 |
物理学 | 300篇 |
出版年
2023年 | 18篇 |
2022年 | 19篇 |
2021年 | 28篇 |
2020年 | 18篇 |
2019年 | 44篇 |
2018年 | 33篇 |
2017年 | 22篇 |
2016年 | 60篇 |
2015年 | 49篇 |
2014年 | 49篇 |
2013年 | 101篇 |
2012年 | 135篇 |
2011年 | 137篇 |
2010年 | 67篇 |
2009年 | 62篇 |
2008年 | 148篇 |
2007年 | 121篇 |
2006年 | 134篇 |
2005年 | 141篇 |
2004年 | 103篇 |
2003年 | 102篇 |
2002年 | 73篇 |
2001年 | 22篇 |
2000年 | 31篇 |
1999年 | 19篇 |
1998年 | 6篇 |
1997年 | 22篇 |
1996年 | 23篇 |
1994年 | 12篇 |
1993年 | 11篇 |
1992年 | 19篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1983年 | 7篇 |
1982年 | 15篇 |
1981年 | 21篇 |
1980年 | 12篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 18篇 |
1975年 | 13篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 4篇 |
排序方式: 共有2044条查询结果,搜索用时 15 毫秒
81.
Synthesis,Characterization, and Electronic Structures of Porphyrins Fused with Polycyclic Aromatic Ring Systems
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Prof. Dr. Tetsuo Okujima Dr. John Mack Dr. Jun Nakamura Gugu Kubheka Prof. Dr. Tebello Nyokong Dr. Hua Zhu Naoki Komobuchi Prof. Dr. Noboru Ono Prof. Dr. Hiroko Yamada Prof. Dr. Hidemitsu Uno Prof. Dr. Nagao Kobayashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14730-14738
A series of porphyrins fused with acenaphthylene, phenanthroline, and benzofluoranthene polycyclic aromatic rings were prepared by means of a 3+1 porphyrin synthesis approach and subsequent retro‐Diels–Alder reaction of bicyclo[2.2.2]octadiene‐fused precursors. Analysis of the magnetic circular dichroism spectra and the results of time‐dependent DFT calculations are used to identify the reasons for the trends observed in the wavelengths and relative intensities of the Q bands of the products. Michl's perimeter model is used as a conceptual framework to explain the changes in the relative energies of the frontier π‐molecular orbitals. 相似文献
82.
Fujisawa Kiyoshi Okano Mitsuki Martín-Pastor Manuel López-Sánchez Rubén Elguero José Alkorta Ibon 《Structural chemistry》2021,32(1):215-224
Structural Chemistry - Experimental multinuclear determination of the chemical shifts, especially 15N and 109Ag, of five silver(I) trinuclear pyrazolate complexes, (PzAg)3, coupled with ZORA... 相似文献
83.
Prof. Shingo Saito Toshiki Sakamoto Naoki Tanaka Ryo Watanabe Takuya Kamimura Kazuki Ota Kathryn R. Riley Keitaro Yoshimoto Yuiko Tasaki-Handa Masami Shibukawa 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(39):10058-10067
In DNA aptamer selection, existing methods do not discriminate aptamer sequences based on their binding affinity and function and the reproducibility of the selection is often poor, even for the selection of well-known aptamers like those that bind the commonly used model protein thrombin. In the present study, a novel single-round selection method (SR-CE selection) was developed by combining capillary electrophoresis (CE) with next generation sequencing. Using SR-CE selection, a successful semi-quantitative and semi-comprehensive aptamer selection for thrombin was demonstrated with high reproducibility for the first time. Selection rules based on dissociation equilibria and kinetics were devised to obtain families of analogous sequences. Selected sequences of the same family were shown to bind thrombin with high affinity. Furthermore, data acquired from SR-CE selection was mined by creating sub-libraries that were categorized by the functionality of the aptamers (e. g., pre-organized aptamers versus structure-induced aptamers). Using this approach, a novel fluorescent molecular recognition sensor for thrombin with nanomolar detection limits was discovered. Thus, in this proof-of-concept report, we have demonstrated the potential of a “DNA Aptaomics” approach to systematically design functional aptamers as well as to obtain high affinity aptamers. 相似文献
84.
85.
Naoki Taka Hiroshi Koga Haruhiko Sato Takenori Ishizawa Tadakatsu Takahashi 《合成通讯》2013,43(23):4263-4269
The novel potassium channel openers benzopyran-4-amides have been synthesized via palladium-catalyzed amidation of 4-bromobenzopyrans under an atmoshere in the presence of an equivalent of potassium iodide. 相似文献
86.
87.
A graph with at least vertices is said to be distance -extendable if, for any matching of with edges in which the edges lie at distance at least pairwise, there exists a perfect matching of containing . In this paper we prove that every 5-connected triangulation on the projective plane of even order is distance 3 7-extendable and distance 4 -extendable for any . 相似文献
88.
89.
Masaaki Yoshifuji Katsuhiro Shibayama Ichiro Shima Naoki Inamoto 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):11-14
Abstract Some reactions of diphosphenes and the related species involving oxidation, reduction, alkylation, sulfurization, and 6η-coordination are described. 相似文献
90.
Abstract The pulse-echo-overlap method was used to measure the longitudinal and transverse wave velocities in single-crystal (100) and (111) samples of InSb up to 3 GPa at room temperature. The peculiar variations of the elastic constants were observed near the covalent-metallic transition. 相似文献