全文获取类型
收费全文 | 289篇 |
免费 | 17篇 |
国内免费 | 11篇 |
出版年
2023年 | 5篇 |
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 6篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 4篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 16篇 |
2010年 | 9篇 |
2009年 | 21篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 15篇 |
2005年 | 16篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 5篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 4篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 3篇 |
排序方式: 共有317条查询结果,搜索用时 0 毫秒
1.
S.P. Patel G. Ranjan V.S. Patel 《International journal of biological macromolecules》1987,9(6):314-320
The rheological properties of aqueous solutions of guar gum (GG) and hydroxyethyl guar gum (HEG) have been investigated. The flow properties of these polysaccharide solutions were studied at the shear rate in the range 1.5–1310s−1 using a Rheotest-2 viscometer. The flow of these polysaccharide solutions was described by equation of state based on Cross model. The basic rheological parameters, like zero shear rate viscosity (ηo), elasticity modulus (Go) and relaxation time (glo) were calculated using simple and established relations. Master viscosity curves indicated that the molecular weight distribution of native guar gum has been changed by hydroxyethylation under specified reaction conditions. The effect of concentration and temperature on ηo and λo has been studied, and the relations among these were established by simple equations. 相似文献
2.
C. E. Scanlon N. R. Chalmers M. A. O. Monteiro da Cruz 《International journal of primatology》1989,10(2):123-136
Three wild groups of common marmoset, Callithrix jacchus jacchus,in north-east Brazil, of approximately similar size, had home ranges between 2.5 and 6.5 ha. But their core areas were similar
in size between 1.0 and 1.5 ha, with a monthly area of heavy use between 1.1 and 1.6 ha. The groups were selective in the
use of their home ranges, even though they were small: they used some areas heavily and others lightly. The core areas had
higher densities of trees that produced gum exudates than did other parts of the home ranges. Our data suggest that a group
of marmosets in this habitat may require a minimum of about 50 gum trees in its home range at a minimum density of about 50
trees/ha. In addition, the animals require suitable trees in which to sleep. We suggest that patches of forest with these
desirable properties remain relatively fixed in size and location over the years and that individual animals are constantly
in flux between them. 相似文献
3.
Secretory tissues in vascular plants 总被引:18,自引:3,他引:15
ABRAHAM FAHN 《The New phytologist》1988,108(3):229-257
4.
Marmosets (Callithrix, Cebuella) in the wild gouge wells in trees and eat the exudates that accumulate there. An artificial gum-tree was made of wooden dowel and filled with Acacia Senegal exudate (gum arabic) dissolved in water. Three families of marmosets avidly gouged and consumed gum from this device, showing all of the behavioral patterns described in nature. The gum-tree cost little and was easy to make. 相似文献
5.
半乳甘露聚糖植物胶加工是我国70年代中期兴起的新兴产业。本文从我国植物资源发展的角度。重点论证了瓜尔豆(Cyanopsis tetragonoloba(L.)Taubert.)、田菁(Sesbania cannabina(Retz.)Pers.)、胡芦巴(Trigonella foenum-graecum L.)的生产情况,认为胡芦巴适应性强、产量高、易于机械化大面积种植与轮作,并具有改良土壤以及经济效益好等优势。因此,发展半乳甘露聚糖胶资源,大量种植胡芦巴是最好的选择。 相似文献
6.
黄单胞菌R5产黄原胶的工艺条件研究 总被引:2,自引:0,他引:2
本文报道了黄单胞菌(Xanthomonascampestris)XC—82·5的诱导株R5发酵生产黄原胶的最适工艺条件。探讨了培养基中不同的碳源、发酵溶氧状况、发酵温度、pH值、菌龄对产胶水平的影响,向时发现:以菜油替代PPE作消泡剂有其独特的优越性;H2O2水不能改善溶氧水平。 相似文献
7.
The polysaccharide component of the stigmatic exudate from Lilium longiflorum has the composition, arabinose (26%), rhamnose (6%), galactose (57%) and glucuronic acid (11%). The highly branched polysaccharide bears a striking resemblance to the acidic polysaccharide exudate from Araucaria bidwillii in belonging to the galactan group and in carrying outer chains terminated by arabinofuranose, rhamnopyranose, galactopyranose and glucuronic acid residues. Both polysaccharides contain the sequence O-rhamnopyranosyl-(1→4)-glucopyranosyluronic acid-(1→6)-galactopyranose in some of the outer chains. 相似文献
8.
9.
N-(2-aminoethyl)-2-acetamidyl gellan gum (GCM-EDA) was prepared by carboxymethylation (via nucleophilic substitution of primary hydroxyl groups of the β-d-glucose unit of gellan gum, in the presence of alkali and chloroacetic acid) and reaction with tert-butyl N-(2-aminoethyl) carbamate (N-Boc-EDA) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as an activator, followed by deprotection with trifluoroacetic acid. The structural confirmation and characterization of N-(2-aminoethyl)-2-acetamidyl gellan gum was performed by spectroscopic, rheological and thermogravimetric analysis, and in vitro tests showed a lack of cytotoxicity which is indicative of the potential of this material to be used in biomedical applications. 相似文献
10.
Preparation and in vitro evaluation of xanthan gum facilitated superabsorbent polymeric microspheres
Shiv Sankar Bhattacharya Farhan Mazahir Subham Banerjee Anurag Verma Amitava Ghosh 《Carbohydrate polymers》2013
Interpenetrating polymer network (IPN) hydrogel microspheres of xanthan gum (XG) based superabsorbent polymer (SAP) and poly(vinyl alcohol) (PVA) were prepared by water-in-oil (w/o) emulsion crosslinking method for sustained release of ciprofloxacin hydrochloride (CIPRO). The microspheres were prepared with various ratios of hydrolyzed SAP to PVA and extent of crosslinking density. The prepared microspheres with loose and rigid surfaces were evidenced by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the IPN formation. Differential scanning calorimetry (DSC) study was performed to understand the dispersion nature of drug after encapsulation. The in vitro drug release study was extensively evaluated depending on the process variables in both acidic and alkaline media. All the formulations exhibited satisfactory physicochemical and in vitro release characteristics. Release data indicated a non-Fickian trend of drug release from the formulations. Based on the results, this study suggest that CIPRO loaded IPN microspheres were suitable for sustained release application. 相似文献