全文获取类型
收费全文 | 532篇 |
免费 | 12篇 |
国内免费 | 1篇 |
专业分类
林业 | 56篇 |
农学 | 12篇 |
95篇 | |
综合类 | 23篇 |
农作物 | 17篇 |
水产渔业 | 114篇 |
畜牧兽医 | 202篇 |
园艺 | 8篇 |
植物保护 | 18篇 |
出版年
2023年 | 1篇 |
2022年 | 7篇 |
2021年 | 12篇 |
2020年 | 10篇 |
2019年 | 5篇 |
2018年 | 10篇 |
2017年 | 10篇 |
2016年 | 18篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 57篇 |
2012年 | 13篇 |
2011年 | 19篇 |
2010年 | 11篇 |
2009年 | 9篇 |
2008年 | 20篇 |
2007年 | 38篇 |
2006年 | 37篇 |
2005年 | 50篇 |
2004年 | 25篇 |
2003年 | 30篇 |
2002年 | 19篇 |
2001年 | 32篇 |
2000年 | 18篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 9篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1965年 | 1篇 |
排序方式: 共有545条查询结果,搜索用时 0 毫秒
61.
Asn-Ala-Leu-Pro-Glu (NALPE) is a strong bitter peptide with a minimum response threshold (MRT) of 0.074 mM. To elucidate the relationship of spatial structure and bitterness on peptides, NALPE and its analogues, NALPW, NALPS, NALPL, NALPP, NALPD, and NALPR, were synthesized and sensorially evaluated. Structural analysis using computer simulation for each peptide revealed that the presence of a polar group and hydrophobic bitter amino acids, the composition of hydrophobic regions, the spatial orientation of the polar group and hydrophobic regions, and the proximity between polar groups and hydrophobic regions faced within the same plane space may be the major determinants for the taste type and intensity of peptide bitterness. 相似文献
62.
Okamura M Ohba Y Kikuchi S Suzuki A Tachizaki H Takehara K Ikedo M Kojima T Nakamura M 《Veterinary microbiology》2008,132(1-2):197-204
In the present study, the loop-mediated isothermal amplification (LAMP) assay was developed to amplify the fragments of the O9 Salmonella-specific insertion element and evaluated in the laboratory for its potential use in a field situation, such as poultry farms. Among the bacteria tested, a positive reaction was observed only for 128 strains of 6 serovars of the O9 group Salmonella, such as Enteritidis (SE) and Pullorum. The detection limit of the LAMP assay was 10(3)CFU/ml, which was more sensitive than that of the polymerase chain reaction (PCR) assay with the same target gene (10(6)CFU/ml). The final results were obtained within 30 min for the LAMP assay, while the PCR assay needed a total of 120 min. When the LAMP assay was applied to the enrichment broth mixed with cecal dropping samples either spiked with SE in vitro or excreted by SE-inoculated hens, the results were comparable to those of the conventional plating method including 2 separate enrichments. In conclusion, the LAMP assay developed in the present study is an effective method for the specific detection of the O9 group Salmonella serovars, including SE. 相似文献
63.
64.
A boron-containing pectic polysaccharide was isolated from Driselase digests of akamatsu (Pinus densiflora) cell wall. The boron-containing polysaccharide was purified by successive column chromatography of Cosmosil C18 OPN, DEAE Sepharose FF, and Superdex 75. The complex had 0.12% (w/w) boron (B) and11B-NMR spectroscopy showed the complex to be the tetrahedral diester form of boron. The sugar composition and glycosyl linkage analyses showed that the sugar portion of the complex was rhamnogalacturonan-II (RG-11). The boron-attached glycosyl residue was identified to be 2-O-Me-xylose-containing apiosyl side chain in RG-II. These results established that the location of borate in the cell wall is conserved among dicots, gramineous monocots, and coniferous gymnosperm.Part of this study was presented at the 8th Cell Wall Symposium, Norwich, September 3, 1998 相似文献
65.
研究结果表明,小菜蛾(diamondbackmoth,Plutelaxylostela)体内酰胺酶广泛存在于其中肠、脂肪体、表皮及头部,酶活力为0.118~0.307μmolg-1min-1.该酶在体细胞中主要以与胞内膜结合的方式存在,也有少部分酶以溶解的方式存在于细胞液中.当反应系统pH值为7.5时,酶活力为最高酶活力的83%;当pH值为8.5时,酶活力达最大值,然后随着pH值的升高,酶活力开始缓慢下降.酶反应在1h内,酶活力与时间变化呈直线关系.对抑太保(Chlorfluazuron)抗性的小菜蛾品系(BKS、TLS、ATABRON、NOMOT、HIOKO、CAKOSHIMA)体内酰胺酶活力明显高于敏感品系(为敏感品系OSS的2.45~2.81倍).抗性品系TLS酰胺酶活力是敏感品系TLN的2.28倍,抗性品系BKS酰胺酶活力是敏感品系BKN的2.18倍. 相似文献
66.
Mohamed Salah Mahjoub Seiichi Takeda Toshifumi Hayashi Daisuke Shiode Takafumi Arimoto Tadashi Tokai 《Fisheries Science》2011,77(2):169-181
Codend selectivity for the jack mackerel Trachurus japonicus and the whitefin jack Kaiwarinus equula were evaluated based on data from trouser trawl experiments carried out in the East China Sea, using a test codend of 60 mm diamond mesh and a control codend made of minnow net with a square mesh of 9 mm bar length. Between-haul variations in parameters and the mean selection curves were tested with the catch data in the SELECT approach, and then the model of between-haul variation in the split parameter with the mean selection curve was chosen as the best fit using Akaike’s information criterion model selection. The 50% retention lengths and the selection ranges were 11.4 and 3.36 cm for jack mackerel and 8.83 and 0.93 cm for whitefin jack, respectively. The selection curve for whitefin jack was sharp, whereas that for jack mackerel was relatively wide. As the estimated split parameters indicated, about 80% of the whitefin jack entered the control codend, but 85 and 90% of the jack mackerel entered the control codend in the second and third hauls, respectively. The inequality in the split parameter is discussed from the viewpoint of the animal’s swimming behavior and water movement based on underwater video observations. 相似文献
67.
With the aim of improving artificial androgenesis in teleost fishes, we tested two methods for producing androgenetic diploids
of amago salmon (Oncorhynchus masou ishikawae), namely, fertilization of gamma-ray irradiated eggs with fused spermatozoa (sperm-fusion method) and the fertilization of
irradiated eggs with untreated sperm followed by the blocking of cell division (mitosis-inhibition method). Our results showed
that the optimal condition for sperm fusion was to treat the sperm with 50% polyethylene glycol (molecular weight 7500) for
100 s. The efficiency of the two methods of androgenesis was compared in terms of fertilization rate, hatching rate, and larval
survival after hatching. The rate of fertilization was lower with the sperm-fusion method than with the mitosis-inhibition
method, but the reverse was true for the hatching rate. The survival rate of hatched larvae was the same with the two methods.
Androgenesis was confirmed with a recessive albino color marker, and all viable offspring were found to be heterozygous based
on analysis of the microsatellite markers. Our results suggest that androgenesis with the sperm-fusion method is a promising
approach with potential applications in both aquaculture breeding programs and the preservation of endangered freshwater fishes. 相似文献
68.
Toshihiro Onitsuka Tomohiko Kawamura Shunsuke Iwanaga Satoshi Ohashi Toyomitsu Horii 《Fisheries Science》2010,76(4):619-623
The dietary value of juvenile stages (gametophyte and juvenile sporophyte) of the brown macroalga Eisenia bicyclis for post-larval and juvenile abalone Haliotis diversicolor of 2.0–6.5 mm in shell length (SL) was examined and compared with that of a benthic diatom, Nitzschia sp., in laboratory experiments. Most abalone actively fed on these diets, but there were large variations in the growth rate
among the diets and among the growth stages of abalone. Growth rates of abalone fed on Nitzschia sp. were highly variable within each growth stage, but showed no clear differences among growth stages. In contrast, in abalone
fed gametophytes or juvenile sporophytes, growth rates linearly increased as abalone grew. Growth rates of >60 μm SL/day were
observed in juveniles of >3 mm SL fed gametophytes, and juveniles of >5 mm SL fed juvenile sporophytes. These results indicate
that the dietary value of the juvenile stages of E. bicyclis for the abalone changes as they grow, and with growth juvenile abalone begin to efficiently utilize gametophytes and juvenile
sporophytes in that order. 相似文献
69.
Fisheries Science - The activity of proteases may be lost during microquantification because of their nonspecific binding to tubes and pipette tips. In this study, the effects of blocking reagents... 相似文献
70.