全文获取类型
收费全文 | 252篇 |
免费 | 13篇 |
专业分类
林业 | 32篇 |
农学 | 11篇 |
基础科学 | 2篇 |
25篇 | |
综合类 | 21篇 |
农作物 | 49篇 |
水产渔业 | 10篇 |
畜牧兽医 | 102篇 |
园艺 | 7篇 |
植物保护 | 6篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 11篇 |
2018年 | 14篇 |
2017年 | 3篇 |
2016年 | 14篇 |
2015年 | 18篇 |
2014年 | 13篇 |
2013年 | 17篇 |
2012年 | 11篇 |
2011年 | 20篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 17篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 4篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1984年 | 2篇 |
1979年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有265条查询结果,搜索用时 15 毫秒
151.
The novel pyrene based dye sensor was designed and synthesized through the reaction between pyrene-1-carboxaldehyde and 4-phenylthiosemicarbazide. This dye sensor showed selectivity and sensitivity binding properties toward F? ion with showing absorption and emission changes in DMSO. These optical properties were investigated by using UV-vis spectrometer and emission spectrophotometer. In addition, electron distributions and HOMO/LUMO values of this dye sensor were simulated and calculated with theoretical calculations of Material Studio 4.3. 相似文献
152.
SummaryThis study was conducted in Mut-Mersin, Turkey, to determine the effects of various times of pruning (no pruning = control; only summer (July, August, or September) pruning in 1994 and 1995; only winter pruning in 1995 and 1996; both summer + winter pruning in 1994-1995 and 1995-1996) on the carbohydrate contents of annual shoots and leaves of young ‘Precoce de Tyrinthe’ apricot trees. Although carbohydrate content in annual shoots was highest in the control trees during the first year, the summer + winter pruning gave the highest values in the second year. In 1995 total sugar and sucrose contents of the leaves was greatest following winter pruning, but starch content was higher in the leaves of control trees. The content of reducing sugars was greatest in leaves of trees pruned in both September + winter. In 1996, levels of total sugars and starch were highest following September pruning, starch content was highest in the control, and; reducing sugars in the leaves were highest following August + winter pruning. 相似文献
153.
Poly(ethylene 2,6-naphthalate) (PEN)/Poly(ethylene glycol) (PEG) copolymers were synthesized by two step reaction during the
melt copolymerization process. The first step was the esterification reaction of dimethyl-2,6-naphthalenedicarboxylate (2,6-NDC)
and ethylene glycol (EG). The second step was the condensation polymerization of bishydroxyethylnaphthalate (BHEN) and PEG.
The copolymers contained 10 mol% of PEG units with different molecular weights. Structures and thermal properties of the copolymers
were studied by using1H-NMR, DSC, TGA, etc. Especially, while the intrinsic viscosities of PEN/PEG copolymers increased with increasing molecular
weights of PEG, but the glass transition temperature, the cold crystallization temperature, and the weight loss temperature
of the copolymers decreased with increasing molecular weights of PEG. Consequently, the hydrophilicities by means of contact
angle measurement and moisture content of the copolymer films were found to be significantly improved with increasing molecular
weights of PEG. 相似文献
154.
S. K. Dhungana B.‐R. Kim J.‐H. Son H.‐R. Kim D.‐H. Shin 《Journal of Agronomy and Crop Science》2015,201(1):10-16
Concerns regarding the safety of transgenic foods have been raised because of possibility of undesirable effects development during genetic engineering. Analysis of phenotypic traits can increase the likelihoods of identifying those unintended effects in dietary composition of the GM crops. Objective of this study was to compare the transgenic lines with their non‐transgenic counterpart. Different vegetative and reproductive traits as well as antioxidant properties were considered to evaluate the transgenic (HV8 and HV23) lines containing CaMsrB2 gene and their non‐transgenic (Ilmi) parent line. Grain size and weight, seed germination, root length, root and shoot dry weight, length and width of flag leaf, plant height, and ligule, stamen and carpel length were not significantly different. Onset and completion of heading in each line occurred almost during the same period. The antioxidant properties in terms of DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) radical scavenging activity and polyphenol content were not statistically different under same treatment condition. The results suggested that the transgenic rice lines containing CaMsrB2 gene were equivalent to their non‐transgenic counterpart without any visible unintended effects. 相似文献
155.
Xiaochuan Li Yajuan Li Zhenzhen Guo Hyungjoo Kim Young-A Son 《Fibers and Polymers》2014,15(5):914-917
A fluorescence “turn-off” and color “turn-on” probe for late IB metal ions (Fe3+/Co2+/Ni2+/Cu2+/Zn2+) was developed based on rhodamine B. The probe was synthesized by condensation between rhodamine B and 8-hydroxyjulolidine-9-carboxaldehyde, which provided excellent selectivity function for late IB metal ions detection. It binds Cu2+ in a 1:1 stoichiometry in acetonitrile solution. This probe displays distinct color and fluorescence change upon the addition of late IB metal ions and little interference with other biologically relevant metal ions. Limit of detection for Cu2+, Fe3+, and Co2+ is higher than that of Zn2+ and Ni2+. In addition, the limit of detection toward Cu2+ is about 312 times lower than the World Health Organization (WHO) recommended level in drinking water. 相似文献
156.
研究了水稻与高梁及玉米的远缘杂交后代及其亲本以及三系杂交组合之种子在不同生态条件(常温湿润,低温湿润,高温浸渍,淹水保温)下的复合发芽特性的差异。 相似文献
157.
Hyuk-Mi Lee Sung-Ok Song Sang-Ho Cha Sung-Bok Wee Karyn Bischoff Sung-Won Park Seong-Wan Son Hwan-Goo Kang Myung-Haing Cho 《Journal of veterinary science (Suw?n-si, Korea)》2013,14(2):143-150
Monoclonal antibody (mAb, NVRQS-DON) against deoxynivalenol (DON) was prepared. DON-Ag coated enzyme linked immunosorbent assay (ELISA) and DON-Ab coated ELISA were prepared by coating the DON-BSA and DON mAb. Quantitative DON calculation ranged from 50 to 4,000 ng/mL for DON-Ab coated ELISA and from 25 to 500 ng/mL for DON-Ag coated ELISA. 50% of inhibitory concentration values of DON, HT-2, 15-acetyl-DON, and nivalenol were 23.44, 22,545, 5,518 and 5,976 ng/mL based on the DON-Ab coated ELISA. Cross-reactivity levels of the mAb to HT-2, 15-acetyl-DON, and nivalenol were 0.1, 0.42, and 0.40%. The intra- and interassay precision coefficient variation (CV) were both <10%. In the mAb-coated ELISA, mean DON recovery rates in animal feed (0 to 1,000 µg/kg) ranged from 68.34 to 95.49% (CV; 4.10 to 13.38%). DON in a buffer solution (250, 500 and 1,000 ng/mL) was isolated using 300 µg of NVRQS-DON and 3 mg of magnetic nanoparticles (MNPs). The mean recovery rates of DON using this mAb-MNP system were 75.2, 96.9, and 88.1% in a buffer solution spiked with DON (250, 500, and 1,000 ng/mL). Conclusively we developed competitive ELISAs for detecting DON in animal feed and created a new tool for DON extraction using mAb-coupled MNPs. 相似文献
158.
Prescribed fire is a common economical and effective forestry practice, and therefore it is important to understand the effects of fire on soil properties for better soil management. We investigated the impacts of low-intensity prescribed fire on the microbial and chemical properties of the top soil in a Hungarian oak (Quercus frainetto Ten.) forest. The research focused on microbial soil parameters (microbial soil respiration (RSM), soil microbial biomass carbon (Cmic) and metabolic quotient (qCO2) and chemical topsoil properties (soil acidity (pH), electrical conductivity (EC), carbon (C), nitrogen (N), C/N ratio and exchangeable cations). Mean annual comparisons show significant differences in four parameters (C/N ratio, soil pH, Cmic and qCO2) while monthly comparisons do not reveal any significant differences. Soil pH increased slightly in the burned plots and had a significantly positive correlation with exchangeable cations Mg, Ca, Mn and K. The mean annual C/N ratio was significantly higher in the burned plots (28.5:1) than in the control plots (27.0:1). The mean annual Cmic (0.6 mg g?1) was significantly lower although qCO2 (2.5 µg CO2–C mg Cmic h?1) was significantly higher, likely resulting from the microbial response to fire-induced environmental stress. Low-intensity prescribed fire caused very short-lived changes. The annual mean values of C/N ratio, pH, Cmic and qCO2 showed significant differences. 相似文献
159.
Jeong MB Son WG Park YW Kim SE Park SA Seo KM 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2011,73(4):431-438
The purpose of the study was to compare two different electroretinography (ERG) instruments used on the same animal in a laboratory setting. Retinal function in both eyes of 12 healthy miniature schnauzers was evaluated under general anesthesia. Scotopic and photopic ERGs were recorded by the HMsERG and the RETIport using the Dog Standard Protocol recommended by the European College of Veterinary Ophthalmologists (ECVO). The waveforms of the ERGs obtained by the two ERG units were similar to those described in previous studies. The 90% reference ranges using the multiple of medians (MoM) showed that the changes in ERG parameters obtained by the HMsERG unit were very similar to those of the RETIport for most ERG responses, except for a few. The results demonstrate that the two ERG systems are comparable for evaluating retinal function in dogs. Further, the results also show that it is necessary to establish ERG system-specific limits of normality in each laboratory or clinic in order to obtain a correct diagnosis, for example by using a graphical representation of the 90% reference range. 相似文献
160.
Iyori K Futagawa-Saito K Hisatsune J Yamamoto M Sekiguchi M Ide K Son WG Olivry T Sugai M Fukuyasu T Iwasaki T Nishifuji K 《Veterinary dermatology》2011,22(4):319-326
Staphylococcal exfoliative toxins are known to digest desmoglein (Dsg) 1, a desmosomal cell–cell adhesion molecule, thus causing intraepidermal splitting in human bullous impetigo, staphylococcal scalded skin syndrome and swine exudative epidermitis. Recently, a novel exfoliative toxin gene (exi), whose sequence shares significant homology with previously identified exfoliative toxins, was isolated from Staphylococcus pseudintermedius. Little is known about the pathogenic involvement of this toxin in canine pustular diseases such as impetigo. The aim of this study was to determine whether EXI, the product of the exi gene, digests canine Dsg1 and causes intraepidermal splitting in canine skin. An exi gene was isolated from chromosomal DNA of an S. pseudintermedius strain obtained from a pustule of a dog with impetigo, and was used to produce a recombinant EXI by Escherichia coli expression. When purified recombinant EXI was injected intradermally into normal dogs, it caused the development of vesicles or erosions with superficial epidermal splitting. In addition, the EXI abolished immunofluorescence for Dsg1, but not for Dsg3, at the injection sites. Moreover, the EXI directly degraded baculovirus‐secreted recombinant extracellular domains of canine Dsg1, but not that of canine Dsg3, in vitro. The EXI also degraded mouse Dsg1α and swine Dsg1, but not human Dsg1, mouse Dsg1β and Dsg1γ. Conversely, recombinant SIET, previously designated as S. intermedius exfoliative toxin, did not cause intraepidermal splitting or degradation of any Dsgs. These findings indicate that EXI has a proteolytic activity that digests canine Dsg1, and this characteristic might be involved in the pathogenesis of intraepidermal splitting in canine impetigo. 相似文献