全文获取类型
收费全文 | 370篇 |
免费 | 7篇 |
专业分类
化学 | 250篇 |
晶体学 | 1篇 |
力学 | 6篇 |
数学 | 30篇 |
物理学 | 90篇 |
出版年
2024年 | 3篇 |
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 18篇 |
2017年 | 3篇 |
2016年 | 13篇 |
2015年 | 5篇 |
2014年 | 13篇 |
2013年 | 34篇 |
2012年 | 22篇 |
2011年 | 29篇 |
2010年 | 16篇 |
2009年 | 5篇 |
2008年 | 19篇 |
2007年 | 10篇 |
2006年 | 21篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1997年 | 3篇 |
1994年 | 4篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1963年 | 1篇 |
1960年 | 3篇 |
1958年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有377条查询结果,搜索用时 0 毫秒
11.
12.
Ajay M. Sorty Kamlesh K. Meena Khushboo Choudhary Utkarsh M. Bitla P. S. Minhas K. K. Krishnani 《Applied biochemistry and biotechnology》2016,180(5):872-882
Halotolerant bacteria associated with Psoralea corylifolia L., a luxuriantly growing annual weed in salinity-affected semi-arid regions of western Maharashtra, India were evaluated for their plant growth-promoting activity in wheat. A total of 79 bacteria associated with different parts viz., root, shoot and nodule endophytes, rhizosphere, rhizoplane, and leaf epiphytes, were isolated and grouped based on their habitat. Twelve bacteria isolated for their potential in plant growth promotion were further selected for in vitro studies. Molecular identification showed the presence of the genera Bacillus, Pantoea, Marinobacterium, Acinetobacter, Enterobacter, Pseudomonas, Rhizobium, and Sinorhizobium (LC027447-53; LC027455; LC027457, LC027459, and LC128410). The phylogenetic studies along with carbon source utilization profiles using the Biolog® indicated the presence of novel species and the in planta studies revealed promising results under salinity stress. Whereas the nodule endophytes had minute plant growth-promoting (PGP) activity, the cell free culture filtrates of these strains enhanced seed germination of wheat (Triticum aestivum L). The maximum vigor index was monitored in isolate Y7 (Enterobacter sp strain NIASMVII). Indole acetic acid (IAA) production by the isolates ranged between 0.22 and 25.58 μg mL?1. This signifies the need of exploration of their individual metabolites for developing next-generation bio-inoculants through co-inoculation with other compatible microbes. This study has potential in utilization of the weed-associated microbiome in terms of alleviation of salinity stress in crop plants. 相似文献
13.
A novel Mitsunobu-based protocol has been developed for the synthesis of a variety of symmetrical and unsymmetrical trithiocarbonates from primary, secondary and tertiary thiols using carbon disulfide, in good to excellent yields. This protocol is mild and efficient compared to other reported methods. 相似文献
14.
A novel process for the one-step chemoselective conversion of alkyl halides into dithiocarbamates as protected amines was
developed using benzyltrimethylammonium hydroxide (Triton-B) in presence of carbon disulfide. Thus, dithiocarbamates of different
amines were prepared in very good to excellent yields. This protocol is mild, chemoselective, and efficient compared to other
methods. 相似文献
15.
A. K. Chaturvedi D. Chaturvedi N. Mishra V. Mishra 《Journal of the Iranian Chemical Society》2011,8(2):396-400
A novel Mitsunobu-based protocol has been developed for the synthesis of carbazates and dithiocarbazates through the variety of corresponding primary, secondary and tertiary alcohols and various kinds of substituted hydrazines using Mitsunobu??s reagent and CO2/CS2 system, in good to excellent yields. 相似文献
16.
Meena Kumari Upendra Kumar Singh Abbul Bashar Khan Maqsood Ahmad Malik 《Journal of Dispersion Science and Technology》2018,39(10):1462-1468
The effect of bovine serum albumin on the surface properties of IL-type gemini surfactant ([C10-4-C10im]Br2), have been investigated by surface tension method. The critical micelle concentration (CMC) as a function of BSA concentrations at various temperatures was investigated. The CMC of [C10-4-C10im]Br2 increases with increasing the concentration of BSA as well as the temperature of the system. The interfacial parameters viz; maximum surface excess concentration (Γmax), the minimum area per molecule (Amin), and surface pressure at CMC (Πcmc) were calculated. In addition, thermodynamic parameters of adsorption and micellization were evaluated by using surface tension data. The results indicated that the binding of [C10-4-C10im]Br2 to BSA is spontaneous and exothermic in nature. The process is entropy driven and hydrophobic interactions are the major driving forces. 相似文献
17.
A method for the determination of lead is described using thiol-functionalized gold nanoparticle. The detection method is based on the prevention of thiol-induced aggregation of gold nanoparticles by lead. Among six thiols, e.g., 4-mercapto-1-butanol, meso-2, 3-dimercaptosuccinic acid, mercaptosuccinic acid, 6-mercapto-1-hexanol, 4-(methylthio)-1-butanol, 1-propanethiol, four (4-mercapto-1-butanol, 6-mercapto-1-hexanol, 4-(methylthio)-1-butanol and 1-propanethiol) induced the aggregation of the gold nanoparticles which was measured by the change in absorbance at 520 and 650?nm. Prior incubation of the gold nanoparticles with lead decreased the 4-(methylthio)-1-butanol-induced aggregation of gold nanoparticles in a dose-dependent manner. A linear inverse relationship between the logarithmic concentration of lead and the ratio of absorbance at 650 to 520 was noted. The method has a dynamic range from 10?nM to 100?µM. However, metals such as mercury and chromium were more effective in comparison with lead in preventing the 4-methylthio-1-butanol-induced aggregation of gold nanoparticles. The method can be used for assessing the heavy metal load in water samples. 相似文献
18.
P. N. Chaturvedi M. J. Patel K. C. Patel R. D. Patel 《Colloid and polymer science》1987,265(7):592-596
The film formation method has been successfully used to grow single crystals and other complex morphological features of low melting form (LMF) and high melting form (HMF) of trans-1,4-polyisoprene (TPIP). Below 40 °C dilute amyl acetate solution gave hexagonal shaped LMF crystals. Thick and elongated hexagonal shaped morphology was shown by HMF crystals at temperatures above 40 °C. Straight faces and sharp corners of the single crystals, and also of complex crystals, acquired round shapes when highly polydispersed TPIP was used for crystallization. 相似文献
19.
JPC – Journal of Planar Chromatography – Modern TLC - The lipophilic character of phytol derivatives has been studied using reverse-phase planar chromatographic procedures.... 相似文献
20.
We present a new approach to Hamilton’s theory of turns for the groups SO(3) and SU(2) which renders their properties, in particular their composition law, nearly trivial and immediately evident upon inspection. We show that the entire construction can be based on binary rotations rather than mirror reflections. 相似文献