全文获取类型
收费全文 | 900篇 |
免费 | 59篇 |
专业分类
林业 | 90篇 |
农学 | 22篇 |
基础科学 | 4篇 |
250篇 | |
综合类 | 37篇 |
农作物 | 48篇 |
水产渔业 | 45篇 |
畜牧兽医 | 358篇 |
园艺 | 27篇 |
植物保护 | 78篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 15篇 |
2020年 | 25篇 |
2019年 | 16篇 |
2018年 | 45篇 |
2017年 | 35篇 |
2016年 | 50篇 |
2015年 | 30篇 |
2014年 | 43篇 |
2013年 | 48篇 |
2012年 | 66篇 |
2011年 | 99篇 |
2010年 | 52篇 |
2009年 | 34篇 |
2008年 | 52篇 |
2007年 | 53篇 |
2006年 | 48篇 |
2005年 | 39篇 |
2004年 | 39篇 |
2003年 | 28篇 |
2002年 | 26篇 |
2001年 | 13篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1997年 | 4篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1987年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1973年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1966年 | 2篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1956年 | 1篇 |
1932年 | 1篇 |
1926年 | 2篇 |
1918年 | 2篇 |
排序方式: 共有959条查询结果,搜索用时 0 毫秒
951.
952.
Milovanović V Radulović N Todorović Z Stanković M Stojanović G 《Plant foods for human nutrition (Dordrecht, Netherlands)》2007,62(3):113-119
The hydro-alcoholic extracts of five Equisetum species, E. arvense L., E. sylvaticum L., E. fluviatile L., E. palustre L. and E. telmateia Ehrh., growing-wild in Serbia were evaluated for their genotoxicity, antimicrobial activity, antioxidant capacity and the results
related to the total phenol content and HPLC flavonoid profiles. The total phenol content was 92–349 μmol expressed as equivalents
of chlorogenic acid per g of dried plant material. Main identified compounds were kaempferol-, quercetin- glycosides and caffeic
acid derivatives. E. telmateia extract showed the greatest antioxidant capacity. Almost all tested microorganisms demonstrated some degree of sensitivity
to the examined extracts. All tested extracts at 62.5 μg/ml showed higher incidence of micronucleus formation than in the
control sample. The obtained data allowed mutual comparison of examined species and their assessment as possible sources of
antioxidants, antimicrobials and/or genotoxic substances. 相似文献
953.
Sibitz C Rudnay EC Wabnegger L Spergser J Apfalter P Nell B 《Veterinary ophthalmology》2011,14(Z1):67-74
Objective To determine the presence of chlamydial species including recently described chlamydial agents as well as the human pathogen Chlamydophila pneumoniae in feline conjunctivitis. Animal studied Twenty five cats without and 49 cats with conjunctivitis were tested for chlamydia using a Chlamydiaceae real time (RT) PCR (targeting the 23S rRNA gene sequence), a Chlamydiales PCR (targeting the 16S rRNA gene sequence), and cell culture. The PCR products of all positive samples were sequenced and subsequently analyzed using a basic local alignment search tool search. Results Chlamydiaceae RT PCR and subsequent sequence analyses identified C. pneumoniae in five cats in the conjunctivitis group. The presence of Chlamydophila felis was shown in two cats with conjunctivitis. Chlamydiae related to uncultured members of Chlamydiales were detected in three conjunctivitis cases and in one cat without clinical symptoms. Conclusion This study detects for the first time, the known human pathogen C. pneumoniae in feline conjunctivitis cases using Chlamydiaceae RT PCR and sequence analyses. 相似文献
954.
Fiona J. Leigh Hugo R. Oliveira Ian Mackay Huw Jones Lydia Smith Petra Wolters Mike Charles Martin Jones Wayne Powell Terence A. Brown Glynis Jones 《Genetic Resources and Crop Evolution》2013,60(1):355-365
Emmer wheat, Triticum dicoccon Schrank was one of the founder crops of Neolithic agriculture. Though its cultivation was largely replaced by hexaploid wheats 2000 years ago, pockets of small scale cultivation can still be found. One such area is the Asturias region of Northern Spain, where emmer wheat remains a traditional crop for high value specialist culinary uses, and farmers grow locally adapted landraces. In order to study the diversity of these landraces, we sampled emmer wheat from different regions of Asturias, and genotyped multiple plants from each village using nuclear and chloroplast microsatellites. A high level of variation was observed with markers from both genomes, including a novel chloroplast haplotype. A strong geographic structure was observed in the Asturian emmer wheats in both the chloroplast markers and the nuclear microsatellite data. 相似文献
955.
Stefanija Šestanović Jelena Peković Slavica Matijević Živana Ninčević Gladan 《Aquaculture Research》2016,47(4):1040-1054
The effects of farming on planktonic microbial communities were investigated at the coastal sea bass/sea bream farm in the oligotrophic middle Adriatic Sea. Analyses of nutrients, chlorophyll a, cyanobacteria (Prochlorococcus), heterotrophic bacteria and nanoflagellates (both pigmented and heterotrophic) were carried out on samples taken during six seasonal cruises at different water depths. Farming activity increased the natural concentrations of some nutrients (ammonium, nitrite, phosphate, dissolved inorganic nitrogen) and changed their seasonal pattern. The values still remained typical for oligotrophic environ‐ments demonstrating no risk for eutrophication. Enhanced nutrient supply provoked an immediate increase in abundances of both autotrophic and heterotrophic microbial groups (except pigmented nanoflagellates) and chlorophyll a. The effect of farming was more visible for the heterotrophic microbial component. Results from this study reveal a potential common pattern of microbial response to farming in the oligotrophic environments. It also suggests the importance of heterotrophic microbial web in transferring the matter and energy released from the fish farms in nutrient poor environments. 相似文献
956.
957.
Ley JP Paetz S Blings M Hoffmann-Lücke P Bertram HJ Krammer GE 《Journal of agricultural and food chemistry》2008,56(15):6656-6664
In order to find new flavor modifiers, various short chain gingerdione derivatives were synthesized as structural analogues of the known bitter masker homoeriodictyol and evaluated by a sensory panel for masking and sweetness enhancing activities. 1-(4-Hydroxy-3-methoxyphenyl)hexa-3,5-dione ([2]-gingerdione) and the homologue 1-(4-hydroxy-3-methoxyphenyl)hepta-3,5-dione ([3]-gingerdione) at concentration ranges 50-500 mg kg (-1) showed the most promising masking activity of 20-30% against bitterness of a 500 mg kg (-1) aqueous caffeine solution. Additionally, both compounds were able to reduce the bitterness of a 5 mg kg (-1) quinine solution by about 20%; however, the bitter tastes of salicine, the model peptide H-Leu-Trp-OH, and KCl solutions were not reduced. Whereas for bitter masking activity a vanillyl moiety seems to be important, some of the tested isovanillyl isomers showed an interesting sweet enhancing effect without exhibiting a significant intrinsic sweetness. The isomer 1-(3-hydroxy-4-methoxyphenyl)hexa-3,5-dione ([2]-isogingerdione) at 100 mg kg (-1) caused a significant and synergistic increase of 27% of sweet taste of a 5% sucrose solution. 相似文献
958.
First report of invasive brown marmorated stink bug Halyomorpha halys (Stål, 1855) in Croatia 下载免费PDF全文
The brown marmorated stink bug, Halyomorpha halys (Stål, 1855) (Hemiptera: Heteroptera: Pentatomidae), has been spreading over Europe since the first documented records from Liechtenstein in 2004 and Switzerland in 2007. It is considered to be a pest in many agricultural crops and a household nuisance. In 2017 the species was observed in Croatia for the first time, in the city of Rijeka on the north Adriatic coast. Halyomorpha halys has already been recorded in three nearby countries (Italy, Hungary and Serbia), and therefore the arrival of this species had been expected from neighbouring populations or from distant sources via trading goods. To identify the pathway of entry, the haplotypes of H. halys (Stål, 1855) individuals were analysed by comparing a part of the mitochondrial COI gene with other haplotypes present in the GenBank database. Individual specimens shared the most common haplotype with nearby Italian and Hungarian populations. 相似文献
959.
Dependence of the common carp (Cyprinus carpio L.) fatty acid profile on diet composition in a semi‐intensive farming system: tissue and time variability 下载免费PDF全文
Trbović Dejana Živić Ivana Stanković Marko Živić Miroslav Dulić Zorka Petronijević Radivoj Marković Zoran 《Aquaculture Research》2017,48(6):3121-3133
Increasing the amount of n‐3 PUFA in carp meat is one of the most important tasks in enhancing its overall quality. However, the relative influence of supplemental feed and natural feed on the FA profile of cultivated carp flesh is not well documented, making it difficult to choose the most efficient strategy. Carp diet composition and diet and flesh fatty acid profiles were simultaneously followed in order to determine the influence of pelleted feed compared to natural feed on fatty acid profiles of carp tissues. Pelleted feed clearly dominated over zooplankton and Chironomidae in the carp diet, producing carp tissue fatty acid profiles closely resembling those of pelleted feed. However, increase in the abundance of zooplankton over the course of the investigation resulting in concomitant increase of its proportion in feed bulk was in strong positive correlation with increase in n‐3 HUFA in the dorsal muscle. n‐3 PUFA enrichment of supplemental feed could be the dominant mechanism in production of carp meat rich in n‐3 PUFA. However, even a small increase in natural feed availability could significantly change the diet of common carp and result in considerable improvement of meat quality with regard to n‐3 HUFA content. 相似文献