全文获取类型
收费全文 | 7538篇 |
免费 | 1019篇 |
国内免费 | 247篇 |
专业分类
化学 | 5697篇 |
晶体学 | 105篇 |
力学 | 222篇 |
综合类 | 6篇 |
数学 | 129篇 |
物理学 | 2645篇 |
出版年
2023年 | 78篇 |
2022年 | 109篇 |
2021年 | 239篇 |
2020年 | 373篇 |
2019年 | 266篇 |
2018年 | 186篇 |
2017年 | 202篇 |
2016年 | 332篇 |
2015年 | 339篇 |
2014年 | 384篇 |
2013年 | 523篇 |
2012年 | 443篇 |
2011年 | 422篇 |
2010年 | 325篇 |
2009年 | 422篇 |
2008年 | 464篇 |
2007年 | 547篇 |
2006年 | 423篇 |
2005年 | 337篇 |
2004年 | 258篇 |
2003年 | 309篇 |
2002年 | 240篇 |
2001年 | 212篇 |
2000年 | 174篇 |
1999年 | 162篇 |
1998年 | 179篇 |
1997年 | 80篇 |
1996年 | 82篇 |
1995年 | 81篇 |
1994年 | 60篇 |
1993年 | 60篇 |
1992年 | 56篇 |
1991年 | 51篇 |
1990年 | 41篇 |
1989年 | 38篇 |
1988年 | 37篇 |
1987年 | 25篇 |
1986年 | 32篇 |
1985年 | 32篇 |
1984年 | 25篇 |
1983年 | 8篇 |
1982年 | 17篇 |
1981年 | 13篇 |
1980年 | 20篇 |
1979年 | 19篇 |
1978年 | 19篇 |
1977年 | 14篇 |
1976年 | 10篇 |
1974年 | 10篇 |
1973年 | 10篇 |
排序方式: 共有8804条查询结果,搜索用时 375 毫秒
1.
Dr. Chen-Ming Lin Maritess Arancillo Jonathan Whisenant Prof. Kevin Burgess 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9484-9488
Secondary structures tend to be recognizable because they have repeating structural motifs, but mimicry of these does not have to follow such well-defined patterns. Bioinformatics studies to match side-chain orientations of a novel hydantoin triazole chemotype ( 1 ) to protein-protein interfaces revealed it tends to align well across parallel and antiparallel sheets, like rungs on a ladder. One set of these overlays was observed for the protein-protein interaction uPA⋅uPAR. Consequently, chemotype 1 was made with appropriate side-chains to mimic uPA at this interface. Biophysical assays indicate these compounds did in fact bind uPAR, and elicit cellular responses that affected invasion, migration, and wound healing. 相似文献
2.
Thomas Marmin Prof. Yves L. Dory 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6707-6711
Cyclohexane and cyclotri-β-alanyl have been used as scaffolds for the design of new C3-symmetric rings incorporating conjugated alkenes and dienes. All three C3-symmetric lactams share the same triangular shape and their crystal system is trigonal. They all belong to the R3 space group, R3m, R3 and R3c, for the increasingly large 12-, 18- and 24-membered rigid rings, respectively. All lactams stack on top of each other, through H-bonds and van der Waals noncovalent interactions, leading to endless supramolecular cylinders and tubes. The largest member of the family leads to tubes, the central pores of which is wide enough to let water in. A common feature of all the lactams is their very large dipole, of around 9 D, according to DFT calculations. Surprisingly, all the resulting cylinders and tubes pack side by side in the crystals, with all the dipoles pointing to the same direction. As a result, all three crystals are anisotropic and appear to be the first members of a new kind of highly polar crystals. 相似文献
3.
Leonor Contreras Ignacio Villarroel Camila Torres Roberto Rozas 《Molecules (Basel, Switzerland)》2021,26(6)
Doxorubicin (DOX), a recognized anticancer drug, forms stable associations with carbon nanotubes (CNTs). CNTs when properly functionalized have the ability to anchor directly in cancerous tumors where the release of the drug occurs thanks to the tumor slightly acidic pH. Herein, we study the armchair and zigzag CNTs with Stone–Wales (SW) defects to rank their ability to encapsulate DOX by determining the DOX-CNT binding free energies using the MM/PBSA and MM/GBSA methods implemented in AMBER16. We investigate also the chiral CNTs with haeckelite defects. Each haeckelite defect consists of a pair of square and octagonal rings. The armchair and zigzag CNT with SW defects and chiral nanotubes with haeckelite defects predict DOX-CNT interactions that depend on the length of the nanotube, the number of present defects and nitrogen doping. Chiral nanotubes having two haeckelite defects reveal a clear dependence on the nitrogen content with DOX-CNT interaction forces decreasing in the order 0N > 4N > 8N. These results contribute to a further understanding of drug-nanotube interactions and to the design of new drug delivery systems based on CNTs. 相似文献
4.
Synthesis,Electronic Properties and WOLED Devices of Planar Phosphorus‐Containing Polycyclic Aromatic Hydrocarbons 下载免费PDF全文
Dr. François Riobé Rózsa Szűcs Dr. Pierre‐Antoine Bouit Dr. Denis Tondelier Bernard Geffroy Fátima Aparicio Julia Buendía Prof. Luis Sánchez Prof. Régis Réau Prof. László Nyulászi Prof. Muriel Hissler 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(17):6547-6556
We describe the synthesis and the physical properties of polyaromatic hydrocarbons (PAHs) containing a phosphorus atom at the edge. In particular, the impact of the successive addition of aromatic rings on the electronic properties was investigated by experimental (UV/Vis absorption, fluorescence, cyclic voltammetry) and theoretical studies (DFT). The physical properties recorded in solution and in the solid state showed that the P‐containing PAHs exhibit properties expected for an emitter in white organic light‐emitting diodes (WOLEDs). 相似文献
6.
7.
《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(9):2399-2399
8.
Diffraction in electron stimulated desorption has revealed a propensity for Cl+ desorption from rest atom vs. adatom areas and unfaulted vs. faulted zones of Cl-terminated Si(1 1 1)-(7 × 7) surfaces. We associate the 15 eV ± 1 eV threshold with ionization of Si-Cl σ-bonding surface states and formation of screened two-hole states with Si 3s character. Similar specificity is observed from A and B reconstructions. This can be due to reduced screening in unfaulted regions and increased hole localization in Si back-bonds within faulted regions. 相似文献
9.
A new unified electroweak model is proposed in this paper. In this unified electroweak model, Higgsmechanism is not used, so no Higgs particle exists in the model. In order to keep the masses of intermediate gaugebosons non-zero, two sets of gauge fields will be introduced. In order to introduce symmetry breaking and to help tointroduce the masses of all fields, a vacuum potential is needed. Except for those terms concerning Higgs particle, thefundamental dynamical properties of this model are similar to those of the standard model. And in a proper limit, thismodel will approximately return to the standard model. The purpose of this paper is not to say that the Higgs particledoes not exist in Nature, it is only to prove that, without a Higgs particle, we can also set up a unified electroweak modelwhich is consistent with present experiments. 相似文献