全文获取类型
收费全文 | 1716篇 |
免费 | 371篇 |
国内免费 | 222篇 |
专业分类
化学 | 1276篇 |
晶体学 | 54篇 |
力学 | 112篇 |
综合类 | 12篇 |
数学 | 138篇 |
物理学 | 717篇 |
出版年
2024年 | 2篇 |
2023年 | 85篇 |
2022年 | 96篇 |
2021年 | 144篇 |
2020年 | 160篇 |
2019年 | 129篇 |
2018年 | 120篇 |
2017年 | 111篇 |
2016年 | 97篇 |
2015年 | 160篇 |
2014年 | 168篇 |
2013年 | 168篇 |
2012年 | 187篇 |
2011年 | 186篇 |
2010年 | 75篇 |
2009年 | 95篇 |
2008年 | 82篇 |
2007年 | 64篇 |
2006年 | 62篇 |
2005年 | 42篇 |
2004年 | 20篇 |
2003年 | 9篇 |
2002年 | 11篇 |
2001年 | 2篇 |
2000年 | 6篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有2309条查询结果,搜索用时 78 毫秒
1.
Interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ 4 × 4 Lax pair
Nonlinear Dynamics - In this paper, we investigate the interactions of the vector breathers for the coupled Hirota system with $$4\times 4$$ Lax pair. Firstly, we give the first-order breather... 相似文献
2.
3.
Theoretical and Mathematical Physics - By introducing shift relations satisfied by a matrix $$\boldsymbol{r}$$ , we propose a generalized Cauchy matrix scheme and construct a discrete second-order... 相似文献
4.
Bohuai Xiao Jianqiao Dong Zhiye Wang Xu Wang Mingjun Sun Jing Guo Gongming Qian Yunchuan Li Shuai Chang 《Chemphyschem》2022,23(7):e202100833
One important prerequisite for the fabrication of molecular functional device strongly relies on the understanding the conducting behaviors of the metal-molecule-metal junction that can respond to an external stimulus. The model Lewis basic molecule 4,4′-(pyridine-3,5-diyl)dibenzonitrile (DBP), which can react with Lewis acid and protic acid, was synthesized. Then, the molecular conducting behavior of DBP, DBP-B(C6F5)3, and DBP-TfOH (DBP-B(C6F5)3, and DBP-TfOH were produced by Lewis acid and protonic acid treatment of DBP) was researched and compared. Given that their identical physical paths for DBP, DBP-B(C6F5)3, and DBP-TfOH to sustain charge transport, our results indicate that modifying the molecular electronic structure, even not directly changing the conductive physical backbone, can tune the charge transporting ability by nearly one order of magnitude. Furthermore, the addition of another Lewis base triethylamine (of stronger alkaline than DBP), to Lewis acid-base pair reverts the electrical properties back to that of a single DBP junction, that is constructive to propose a useful but simple strategy for the design and construction of reversible and controllable molecular device based on pyridine derived molecule. 相似文献
5.
6.
7.
Peng-Yan Gui Xiao-Hui Yan Wen-Juan Yuan Yuan-Liang Ma Xiao Ding Shuai Liu 《Natural product research》2019,33(19):2830-2836
A new A, D-seco limonoid, named 12-acetyloxyperforatin (1), along with three known ones, were isolated from the leaves of Harrisonia perforata. Their structures were elucidated on the basis of spectroscopic analysis, including extensive NMR techniques and computational modelling. These compounds showed no inhibitory activity against the 11β-HSD1 enzyme. 相似文献
8.
以尿素和钨酸铵为原料采用浸渍法制备了金属氧化物三氧化钨(WO3)与石墨相氮化碳(g-C3N4)异质结复合材料WO3/g-C3N4。采用XRD、UV-vis、SEM、PL和XPS表征手段考察了催化剂的理化性质,发现WO3与g-C3N4存在较好的相互作用和电子转移,保证了WO3/g-C3N4本身所具有较高的氧化脱硫活性。以WO3/g-C3N4作为催化剂,过氧化氢异丙苯为氧化剂,考察其光催化氧化脱硫性能,在反应温度80℃,O/S物质的量比为3.0的反应条件下,反应180 min,二苯并噻吩(DBT)转化率可以达到72.79%。通过游离基捕获实验,发现超氧自由基(·O2-)、电子(e-)、羟基自由基(·OH)起到了促进反应速率的作用,并对该体系的反应机理进行了探讨。 相似文献
9.
Bowen Yang Feng Cai Shuai Huang Prof. Dr. Haifeng Yu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(10):4064-4071
Imprinting nanopatterns on flexible substrates has diverse applications in advanced fabrication. However, the traditional thermal nanoimprint lithography (T-NIL) often causes shrinkage upon cooling. Here, a simple yet versatile method is introduced to fabricate multiple nanopatterns on a flexible substrate coated with an azopolymer by combining athermal nanoimprint lithography (AT-NIL) and photolithography. The azopolymer has various mechanical properties upon photoirradiation: 1) phototunable glass-transition temperatures (Tg) and concomitantly photoinduced switch from glassy plastic to viscoplastic polymer; 2) prominent modulation of viscoplasticity under light illumination at different wavelengths. Regionally selective multiple nanopatterns are conveniently fabricated, presenting angle-dependent structural color images on poly(ethylene terephthalate) (PET) substrates. The flexible, athermal and multiple nanopatterning method has the potential for on-demand fabrication of complex nanopatterns. 相似文献
10.
Meccanica - Based on the classification ability of a convolutional neural network (CNN), this paper proposes a structural damage detection method in which a CNN is used to classify the location and... 相似文献