全文获取类型
收费全文 | 405篇 |
免费 | 17篇 |
国内免费 | 1篇 |
专业分类
林业 | 26篇 |
农学 | 17篇 |
基础科学 | 1篇 |
37篇 | |
综合类 | 25篇 |
农作物 | 105篇 |
水产渔业 | 44篇 |
畜牧兽医 | 145篇 |
园艺 | 6篇 |
植物保护 | 17篇 |
出版年
2023年 | 5篇 |
2022年 | 22篇 |
2021年 | 25篇 |
2020年 | 10篇 |
2019年 | 10篇 |
2018年 | 13篇 |
2017年 | 12篇 |
2016年 | 12篇 |
2015年 | 18篇 |
2014年 | 27篇 |
2013年 | 24篇 |
2012年 | 33篇 |
2011年 | 27篇 |
2010年 | 23篇 |
2009年 | 15篇 |
2008年 | 14篇 |
2007年 | 32篇 |
2006年 | 24篇 |
2005年 | 23篇 |
2004年 | 5篇 |
2003年 | 11篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1969年 | 1篇 |
排序方式: 共有423条查询结果,搜索用时 15 毫秒
141.
Young Eun Du Eun Seo Bae Yeonjung Lim Jang-Cheon Cho Sang-Jip Nam Jongheon Shin Sang Kook Lee Seung-Il Nam Dong-Chan Oh 《Marine drugs》2021,19(4)
Two new secondary metabolites, svalbamides A (1) and B (2), were isolated from a culture extract of Paenibacillus sp. SVB7 that was isolated from surface sediment from a core (HH17-1085) taken in the Svalbard archipelago in the Arctic Ocean. The combinational analysis of HR-MS and NMR spectroscopic data revealed the structures of 1 and 2 as being lipopeptides bearing 3-amino-2-pyrrolidinone, d-valine, and 3-hydroxy-8-methyldecanoic acid. The absolute configurations of the amino acid residues in svalbamides A and B were determined using the advanced Marfey’s method, in which the hydrolysates of 1 and 2 were derivatized with l- and d- forms of 1-fluoro-2,4-dinitrophenyl-5-alanine amide (FDAA). The absolute configurations of 1 and 2 were completely assigned by deducing the stereochemistry of 3-hydroxy-8-methyldecanoic acid based on DP4 calculations. Svalbamides A and B induced quinone reductase activity in Hepa1c1c7 murine hepatoma cells, indicating that they represent chemotypes with a potential for functioning as chemopreventive agents. 相似文献
142.
Oh-Jin Kwon Seung-Taek Oh Sang-Do Lee Na-Ri Lee Chang-Hoon Shin Jong-Shin Park 《Fibers and Polymers》2007,8(4):347-355
Hydrophilic and flexible polyurethane foams were prepared using sodium alginate as a polyol, and characterized by optical
microscopy, FT-IR spectroscopy, density measurements, volume swelling, and water absorbency. Optical microscopy revealed that
the resulting cells were closed with round and elongated shapes. FT-IR confirmed that the urethane linkages were formed between
the isocyanate and sodium-alginate. As an indirect measurement of porosity, the apparent density indicated an initial decrease
followed by an increase with increasing glycerin content. The volume-swelling ratio was initially constant, followed by a
gradual decrease with glycerin content. The volume swelling ratio increased with PEG molecular weight. The water absorbency
initially increased, followed by a decrease with increasing glycerin content. The correlation-ships between water absorbency,
density, and volume-swelling ratio indicated that the absorbency was predominantly influenced by density when the PEG molecular
weight was low and was greatly affected by the volume-swelling ratio when the PEG molecular weight was relatively high. 相似文献
143.
Young Hee Joung Jerry L. Hill Jung Oh Hyun Ding Mu Juchun Luo Do Hyung Lee Takayuki Kawahara Jeung Keun Suh Mark S. Roh 《林业研究》2013,24(1):53-60
To confirm a hybrid swarm population of Pinus densiflora × P. sylvestris in Jilin, China, we used needles and seeds from P. densiflora, P. sylvestris, and P. densiflora × P. sylvestris collected from natural stands or experimental stations to study whether shoot apex morphology of 4- year old seedlings can be correlated with the sequence of a chloroplast DNA simple sequence repeat marker (cpDNA SSRs). Total genomic DNA was extracted and subjected to sequence analysis of the pine cpDNA SSR marker Pt15169. Results show that morphological characters from 4-year old seedlings did not correlate with sequence variants of this marker. Marker haplotypes from all P. sylvestris trees had a CTAT element that was absent from all sampled P. densiflora trees. However, both haplotype classes involving this insertion/deletion element were found in a P. densiflora × P. sylvestris population and its seedling progeny. It was concluded that the P. densiflora × P. sylvestris accessions sampled from Jilin, China resulted from bi-directional crosses, as evidenced by both species’ cpDNA haplotypes within the hybrid swarm population. 相似文献
144.
Due to the lack of large cross-section wood, the concern regarding the utilization of small-diameter logs from forest thinning has increased as a worldwide issue recently. Round shape is advantageous to efficient use of small-diameter logs, there is a difficulty of drying and preservative treatment. It is necessary to apply a new technique. In this study, center-boring technology was applied to improve the efficiency of manufacturing. The effect of a hole was not expected to make a significant effect on the flexural performance because the hole is located at the centroid of beam under bending moment. Unlike a round timber beam, the failure of center-bored round timber beam starts with a crack and is followed by a longitudinal split. When designing center-bored round timber as guardrail beam, additional strength reduction by flattening should be considered. 相似文献
145.
Seyeon Oh Myeongjoo Son Kyung-A Byun Ji Tae Jang Chang Hu Choi Kuk Hui Son Kyunghee Byun 《Marine drugs》2021,19(6)
Nonalcoholic fatty liver disease (NAFLD), which promotes serious health problems, is related to the increase in the nucleotide-binding oligomerization domain-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome and pyroptosis by a high-fat diet (HFD). Whether dieckol (DK), a component of Ecklonia cava extracts (ECE), attenuated NAFLD in an HFD-induced NAFLD animal model was evaluated. The expression of high mobility group box 1/Toll-like receptor 4/nuclear factor-κB, which initiated the NLRP3 inflammasome, was increased in the liver of HFD-fed animals and significantly decreased with ECE or DK administration. The expression of NLRP3/ASC/caspase-1, which are components of the NLRP3 inflammasome, and the number of pyroptotic cells were increased by HFD and decreased with ECE or DK administration. The accumulation of triglycerides and free fatty acids in the liver was increased by HFD and decreased with ECE or DK administration. The histological NAFLD score was increased by HFD and decreased with ECE or DK administration. The expression of lipogenic genes (FASN, SREBP-2, PPARγ, and FABP4) increased and that of lipolytic genes (PPARα, CPT1A, ATGL, and HSL) was decreased by HFD and attenuated with ECE or DK administration. In conclusion, ECE or DK attenuated NAFLD by decreasing the NLRP3 inflammasome and pyroptosis. 相似文献
146.
B‐J Lee S‐S Kim J‐W Song D‐H Oh J‐H Cha J‐B Jeong M‐S Heo K‐W Kim K‐J Lee 《Journal of fish diseases》2013,36(7):617-628
Two consecutive studies were conducted to evaluate the dietary supplementation of citrus by‐products (CB) fermented with probiotic bacteria on growth performance, feed utilization, innate immune responses and disease resistance of juvenile olive flounder. In Experiment I, five diets were formulated to contain 0% (control) or 3% four different CB fermented with Bacillus subtilis (BS), Enterococcus faecium (EF), Lactobacillus rhamnosus (LR) and L. plantarum (LP) (designated as CON, CBF‐BS, CBF‐EF, CBF‐LR and CBF‐LP, respectively). During 10 weeks of a feeding trial, growth performance and feed efficiency were not significantly different among all the fish groups. However, fish fed CBF containing diets had significantly higher survivals than the CON group. Disease resistance of fish against Edwardsiella tarda was increased by the fermentation of CB. In Experiment II, we chose the BS as a promising probiotic and formulated five diets to contain 0%, 2%, 4%, 6% and 8% CBF‐BS. Growth performance was not significantly affected by the CBF‐BS supplementation during 6 weeks of a feeding trial. Innate immunity of fish was significantly enhanced by CBF‐BS supplementation. Myeloperoxidase and lysozyme activities were increased in a dose‐dependent manner by dietary CBF‐BS inclusions. In a consecutive challenge test against E. tarda, an increased disease resistance was found by CBF‐BS supplementation. These studies indicate that the fermentation process of CB with probiotic has beneficial effects on innate immunity and thereby increases disease resistance of olive flounder against E. tarda. Bacillus subtilis can be used as a promising probiotic microbe for by‐product fermentation in fish feeds. 相似文献
147.
Jeong Yun Lee Sung Jin Oh Min Suk Lee Jong Yun Park Jung Jae Ryu Ki Hoon Lee 《Fibers and Polymers》2012,13(9):1209-1213
Phytoncide, a volatile essential oil produced by plants and trees, has not only anti-microbial activity, but also a stress relieving effect. We prepared a sheath/core type melt-spun fiber that releases phytoncide for a prolonged time. The fiber is comprised of a nylon sheath and a polypropylene (PP) core material. Phytoncide-containing microcapsules are embedded within the core part. The phytoncide microcapsule-containing nylon/PP sheath/core (M-Ny/PP) fiber has suitable mechanical properties for textile application. The phytoncide release from the microcapsule-containing the PP fiber (M-PP) reached a plateau level after 4 days and maintained that level for an additional 7 days, indicating a zero-order release after the initial burst. The M-Ny/PP fiber emitted the volatile phytoncide even though the fiber was spun at 250 °C. The release of phytoncide decreased in the M-Ny/PP fiber compared to the phytoncide microcapsule-containing PP (M-PP) fiber due to the dense sheath layer. 相似文献
148.
149.
Olive flounder (Paralichthys olivaceus) are highly protected from a viral hemorrhagic septicemia virus (VHSV) challenge following Polyinosinic–polycytidylic acid [Poly(I:C)] administration. In the present study, we investigated the change of VHSV titer in olive flounder following Poly(I:C) administration to understand virus dynamics in the fish. Fish challenged with VHSV that were not administered Poly(I:C) showed 63.8 % cumulative mortality. VHSV was detectable the next day after VHSV challenge and multiplied very quickly to around 107.5 TCID50/g in 3 days. About 107 TCID50/g titer was maintained until 7 days and then subsequently decreased and almost disappeared after 21 days. In contrast, 1.7 % cumulative mortality was observed in fish administered Poly(I:C), and no VHSV titer was detected in almost all fish for 28 days. These results confirm that multiplication of VHSV is strongly down-regulated in olive flounder following Poly(I:C) administration. 相似文献
150.
Oh MJ Kitamura SI Kim WS Park MK Jung SJ Miyadai T Ohtani M 《Journal of fish diseases》2006,29(7):415-421
Turbot iridovirus (TBIV), a member of the genus Megalocytivirus in the family Iridoviridae, was isolated from diseased turbot, Psetta maximus (L.), in Korea in 2003. In this study, experimental infection of turbot, Japanese flounder, Paralichthys olivaceus (Temminck & Schlegel), and rock bream, Oplegnathus fasciatus (Temminck & Schlegel), with TBIV was performed to evaluate the viral susceptibility of these fish species. After virus exposure, the mortalities of turbot reared at 22 and 25 degrees C were 60% and 100%, respectively, suggesting that TBIV is the causative agent of the mass mortality of turbot that occurred in Korea in 2003. Moreover, TBIV was detected in Japanese flounder and rock bream by polymerase chain reaction after experimental infection (26 days post-inoculation) despite no viral pathogenicity in these fish, suggesting that these two fish species are also susceptible to the virus. It is possible that horizontal transmission of TBIV occurs among these three fish species because turbot is routinely cultured with Japanese flounder and rock bream in Korea. 相似文献