全文获取类型
收费全文 | 165篇 |
免费 | 6篇 |
专业分类
化学 | 128篇 |
力学 | 4篇 |
数学 | 8篇 |
物理学 | 31篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 11篇 |
2013年 | 20篇 |
2012年 | 20篇 |
2011年 | 11篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1960年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有171条查询结果,搜索用时 31 毫秒
101.
1,2‐Diaryl‐4‐phenylmethylene‐2‐imidazolin‐5‐ones were obtained by the interaction of primary amines with 2‐phenyl‐4‐phenylmethylene‐2‐oxazolin‐5‐one using acidic alumina or montmorillonite K10 clay under microwave irradiation (MWI). The same reaction over basic alumina gave arylamides of α‐arylamido‐β‐arylacrylic acids in good yield. Usage of acidic alumina for cyclization gave better results in comparison with clay. This procedure highlights the versatility of various solid supports. 相似文献
102.
103.
DNA governs the storage and transfer of genetic information through generations in all living systems with the exception of some viruses. Its physicochemical nature and the Watson–Crick base pairing properties allow molecular constructions at nanometer length, thereby enabling the design of desired structural motifs, which can self‐assemble to form large supramolecular arrays and scaffolds. The tailor‐made DNAs have been an interesting material for such designed nanoscale constructions. However, the synthesis of specific structures with a desired molecular function is still in its infancy and therefore has to be further explored. To add a new dimension to this approach, we have synthesized a rigid three‐way branched adamantane motif, which is capable of forming highly stable DNA networks. The moiety generated could serve as a useful building block for DNA‐based nanoconstructions. 相似文献
104.
105.
The antibandwidth maximization problem (AMP) consists of labeling the vertices of a n-vertex graph G with distinct integers from 1 to n such that the minimum difference of labels of adjacent vertices is maximized. This problem can be formulated as a dual problem
to the well known bandwidth problem. Exact results have been proved for some standard graphs like paths, cycles, 2 and 3-dimensional
meshes, tori, some special trees etc., however, no algorithm has been proposed for the general graphs. In this paper, we propose
a memetic algorithm for the antibandwidth maximization problem, wherein we explore various breadth first search generated
level structures of a graph—an imperative feature of our algorithm. We design a new heuristic which exploits these level structures
to label the vertices of the graph. The algorithm is able to achieve the exact antibandwidth for the standard graphs as mentioned.
Moreover, we conjecture the antibandwidth of some 3-dimensional meshes and complement of power graphs, supported by our experimental
results. 相似文献
106.
In this paper, it is shown that at a high bit rate of 80-Gb/s alternate polarization of adjacent bits in a Wavelength Division Multiplexed (WDM) transmission link improves the system performance in terms of improved Q factor and minimum bit error rate (BER). Alternate Polarization Return to Zero (al-PRZ) further suppresses the non-linear effects at higher power levels of 25 dBm per channel and also improves the transmission length to 640 km for a N × 80-Gb/s WDM system and hence results in an improvement of BER to 10−20. 相似文献
107.
Schiff base supported mononuclear organotin(IV) complexes: Syntheses,structures and fluorescence cell imaging
下载免费PDF全文
![点击此处可从《应用有机金属化学》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Richa Vinayak Dhritiman Dey Dipanjan Ghosh Dhrubajyoti Chattopadhyay Abhrajyoti Ghosh Hari Pada Nayek 《应用有机金属化学》2018,32(3)
Three mononuclear organotin(IV) complexes supported by Schiff bases have been synthesized. The complexes [(C6H5)2Sn(L)] ( 1 ), [(t‐Bu)2Sn(L)] ( 2 ) and [(t‐Bu)2Sn(L')] ( 3 ) (L, L' = deprotonated Schiff bases) were obtained in good yield by the reaction of Schiff bases H 2 L or H 2 L′ with corresponding diorganotin dichlorides respectively. All newly synthesized complexes were characterized by means of FT‐IR spectroscopy, elemental analysis and multinuclear (1H, 13C and 119Sn) NMR spectroscopy. In addition, single crystal X‐ray diffraction analyses were employed to establish the solid state molecular structures of these complexes. The structures of 1 – 3 reveal that all complexes are mononuclear with a five‐coordinated tin(IV) centre in it. The absorption and emission properties of all complexes have been investigated. Moreover, cytotoxicity and fluorescence cell imaging studies of theses complexes have been performed. 相似文献
108.
109.
A complete mass spectral fragmentation pattern of naturally abundant ethyldigermane is presented. The base peak occurs at m/e 148 in the Ge2H×=0←5 + region and not in the parent region. Three metastable peaks are observed at m/e 52.70, m/e 59.36, and m/e 125.63 respectively. 相似文献
110.
Structural Chemistry - Certain DNA minor groove binders, especially bis-benzimdazole containing compounds, such as Hoechst 33258 and its derivatives, act as potent topoisomerase I inhibitors. The... 相似文献