全文获取类型
收费全文 | 726篇 |
免费 | 29篇 |
专业分类
林业 | 74篇 |
农学 | 38篇 |
基础科学 | 2篇 |
89篇 | |
综合类 | 38篇 |
农作物 | 27篇 |
水产渔业 | 52篇 |
畜牧兽医 | 398篇 |
园艺 | 6篇 |
植物保护 | 31篇 |
出版年
2022年 | 12篇 |
2021年 | 22篇 |
2020年 | 13篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 22篇 |
2016年 | 22篇 |
2015年 | 14篇 |
2014年 | 28篇 |
2013年 | 41篇 |
2012年 | 31篇 |
2011年 | 43篇 |
2010年 | 20篇 |
2009年 | 30篇 |
2008年 | 35篇 |
2007年 | 45篇 |
2006年 | 34篇 |
2005年 | 37篇 |
2004年 | 30篇 |
2003年 | 28篇 |
2002年 | 28篇 |
2001年 | 27篇 |
2000年 | 21篇 |
1999年 | 20篇 |
1998年 | 5篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 8篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1966年 | 3篇 |
1959年 | 1篇 |
排序方式: 共有755条查询结果,搜索用时 0 毫秒
91.
Water adsorption capacities were evaluated for moso bamboo samples that were heated at 200°C for various times and conditioned
in a closed container at 97% relative humidity at 20°C. Logistic regression analysis was used for curve fitting to the adsorption
data and its parameters were analyzed. These parameters were compared with those derived previously from the Dubinin and Radushkevich
theory. The properties of the heat-treated samples changed after 5 h of heating. With less than 5 h of heating, hydroxyl groups
provided the main adsorption sites but their numbers decreased on heating. After 5 h, gasifi cation of the bamboo increased
and capillaries formed.
Part of this article was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, August 2007 相似文献
92.
Saito M Saito K Kunisaki N Kimura S 《Journal of agricultural and food chemistry》2002,50(24):7169-7174
We have investigated the inhibitory effects of polyphenols from natural products, such as green tea, bilberry, grape, ginkgo, and apple, on rainbow trout gelatinase activities. Gelatinases from the skin, muscle, and blood of rainbow trout contained serine proteinase, metalloproteinase, and other proteinase activities as measured by gelatin zymography. The polyphenols of green tea caused the strong inhibition of some gelatinase activities when compared with those of the other products. This inhibition was quite similar to that of metalloproteinase by ethylenediaminetetraacetic acid, suggesting that the effects of green tea polyphenols on proteinase activities are specific for metalloproteinases. The major catechins of green tea polyphenols were then separated and identified by reverse-phase chromatography to be (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin, (-)-epicatechin gallate, and (-)-epicatechin. The effects of these catechins on gelatinase activities were examined; the most potent inhibitor of metalloproteinase activities was found to be EGCG. These results have indicated that green tea polyphenols including EGCG are useful for regulating metalloproteinase activities of fish meat. 相似文献
93.
A Ibe K Saito M Nakazato Y Kikuchi K Fujinuma T Nishima 《Journal of the Association of Official Analytical Chemists》1991,74(4):695-698
A liquid chromatographic (LC) procedure is described for the determination by dansylation of the following 16 kinds of biogenic amines found in wine: monomethylamine (MM), ethylamine (EM), iso- and n-propylamine (Pr), iso- and n-butylamine (Bu), iso- and n-amylamine (Am), pyrrolidine (PY), 2-phenethylamine (PH), tryptamine (TR), putrescine (PU), cadaverine (CA), histamine (HI), tyramine (TY), and spermidine (SP). The amines in white and red wine were applied to a column of Amberlite CG-50 type I resin (Na-form) after the column had been washed with water and eluted with 1N hydrochloric acid. This eluate was evaporated to dryness under reduced pressure and derivatized with dansyl chloride (DNS). LC separations were performed on Finepak SIL C18S and LiChrosorb RP-8 columns with an acetonitrile-water elution gradient. In the survey of commercial wines by this method, most of the samples were found to contain 12 amines, including iso-Am, CA, PU, TY, and others. The highest levels of these amines were 4.84 micrograms PU/mL in red wine, and 5.11 micrograms iso-Am/mL in white wine. The total levels of amines in red wine were comparatively higher than in white wine. 相似文献
94.
An alkaline phosphatase in the intraradical hyphae of arbuscular mycorrhizal fungi was found to be closely related to an
improvement of plant growth. To detect the phosphatase activity in a crude extract of mycorrhizal roots, phosphatase isozymes
in mycorrhizal and non-mycorrhizal onion roots were compared with those in Gigaspora margarita by electrophoresis. A mycorrhiza-specific band was found when the phosphatase was stained under alkaline conditions. To clarify
the origin of this phosphatase, the phosphatase extracted from intraradical hyphae was also compared with the phosphatase
from mycorrhizal roots by electrophoresis. The intraradical hyphae was isolated from mycorrhizal roots by enzyme digestion
followed by Percoll gradient centrifugation. The soluble protein was extracted from the hyphae by ultra-sonication after treatment
with chitinase. A phosphatase in the hyphal soluble protein showed a similar, but slightly higher, relative mobility on the
gel, compared with the mycorrhiza-specific phosphatase from roots. By adding the hyphal extract to the root extract, the relative
mobility of the mycorrhiza-specific phosphatase was slightly changed and became identical to that of the phosphatase in the
hyphae. This indicated that the specific band of phosphatase found in the crude extract from mycorrhizal roots was of intraradical
hyphal origin.
Received: 16 April 1997 相似文献
95.
We describe a new molecular class of genetic-pairing system that has a native DNA backbone but has all four base pairs replaced by new, larger pairs. The base pairs include size-expanded analogs of thymine and of adenine, both extended by the width of a benzene ring (2.4 A). The expanded-diameter double helices are more thermodynamically stable than the Watson-Crick helix, likely because of enhanced base stacking. Structural data confirm a right-handed, double-stranded, and base-paired helical form. Because of the larger base size, all the pairs of this helical system are fluorescent, which suggests practical applications in detection of natural DNA and RNA. Our findings establish that there is no apparent structural or thermodynamic prohibition against genetic systems having sizes different from the natural one. 相似文献
96.
Hirokazu Hikono Masaji Mase Aya Matsuu Megumi Nakayama Takehiko Saito 《Veterinary immunology and immunopathology》2013,151(1-2):83-89
Because it is expected to induce cross-reactive serum and mucosal antibody responses, mucosal vaccination against highly pathogenic avian influenza (HPAI) is potentially superior to conventional parenteral vaccination. Here, we tested whether intraocular vaccination with an inactivated AI virus induced protective antibody responses in chickens. Chickens were inoculated intraocularly twice with 104 hemagglutination units of an inactivated H5N1 HPAI virus. Four weeks after the second vaccination, the chickens were challenged with a lethal dose of the homologous H5N1 HPAI virus. Results showed that most of the vaccinated chickens mounted positive antibody responses. The median serum hemagglutination inhibition titer was 1:80. Addition of CpG oligodeoxynucleotide 2006 or cholera toxin to the vaccine did not enhance serum antibody titers. Cross-reactive anti-hemagglutinin IgG, but not IgA, was detected in oropharyngeal secretions. In accordance with these antibody results, most vaccinated chickens survived a lethal challenge with the H5N1 HPAI virus and did not shed the challenge virus in respiratory or digestive tract secretions. Our results show that intraocular vaccination with an inactivated AI virus induces not only systemic but also mucosal antibody responses and confers protection against HPAI in chickens. 相似文献
97.
Shinpei Banno Hidenari Saito Hiroshi Sakai Toshihiko Urushibara Kentaro Ikeda Takeshi Kabe Isao Kemmochi Makoto Fujimura 《Journal of General Plant Pathology》2011,77(5):282-291
Verticillium longisporum and V. dahliae, causal agents of Verticillium wilt, are spreading through the cabbage fields of Gunma Prefecture. Using the V. longisporum-specific intron within the 18S rDNA and differences between ITS 5.8S rDNA sequences in Japanese isolates of V. longisporum and V. dahliae, we developed three quantitative nested real-time (QNRT) PCR assays. The QNRT-PCR quantification of V. longisporum or V. dahliae in cabbage field soil was consistent with the severity of Verticillium wilt disease in those fields. In field trials of resistant
cultivar YR Ranpo grown for three seasons in soil infested with the pathogen, disease severity and pathogen density in the
soil were significantly reduced in a field moderately contaminated by V. dahliae, but only slightly reduced in a highly contaminated field. These results suggest that continuous cultivation of a resistant
cultivar is an effective way to reduce the pathogen population. QNRT-PCR assays provide a powerful analytical tool to evaluate
the soil population dynamics of V. longisporum and V. dahliae for disease management. 相似文献
98.
Elisabete Yurie Sataque Ono Elaine Cunha Moreno Mario Augusto Ono Carolina Nachi Rossi Gervásio Hitoshi Saito Édio Vizoni Yoshitsugu Sugiura Elisa Yoko Hirooka 《European journal of plant pathology / European Foundation for Plant Pathology》2011,131(4):653-660
In this study the effect of different cropping systems and crop successions was evaluated on natural Fusarium sp. contamination and fumonisin levels in corn. The cropping systems consisted of a conventional and no-tillage area cultivated
with corn in the summer following either oats or fallow in the winter (2006 and 2007 growing seasons). In addition, the effect
of applying nitrogen fertilizer (0, 22.5, 45.0, 90.0 and 90.0 kg ha−1 nitrogen supplemented with potassium oxide) on fumonisin contamination was evaluated in the 2006 growing season. Fusarium sp. was detected in 90% samples in 2006 and in 100% samples in 2007. In both growing seasons, no-till corn following oats
showed the highest mean fumonisin levels and differed significantly (P < 0.05) from all the others (2006) and from conventional till corn following either oats or fallow in the winter (2007).
Fumonisin levels ranged from 0.13 to 19.52 μg g−1 (mean 6.97 μg g−1) and from 3.70 to 7.75 μg g−1 (mean 6.29 μg g−1) in no-till corn following oats from the 2006 and 2007 growing seasons, respectively. Plots treated with 0 kg ha−1 and 22.5 kg ha−1 nitrogen showed the highest mean fumonisin levels and differed significantly from those with 45.0 and 90 kg ha−1 nitrogen. Fumonisin levels correlated negatively (P < 0.05) with the nitrogen fertilization rates. Although no-till is advantageous from a soil conservation standpoint, it may
enhance the potential for fumonisin contamination in corn. 相似文献
99.
Megumu Tanahashi Takashi Nakano Hajime Akamatsu Motoichiro Kodama Hiroshi Otani Kumiko Osaki-Oka 《European journal of plant pathology / European Foundation for Plant Pathology》2016,145(4):787-795
A disease caused by Alternaria alternata occurred on the leaves of European pear cultivar Le Lectier in Niigata Prefecture, Japan, and was named black spot of European pear. In conidial inoculation tests, the causal pathogen induced not only small black lesions on the leaves of European pear cultivar Le Lectier, but severe lesions on the leaves of apple cultivar Red Gold, which is susceptible to the A. alternata apple pathotype (previously called A. mali) causing Alternaria blotch of apple. Interestingly, the apple pathotype isolate showed the same pathogenicity as the European pear pathogen. HPLC analysis of the culture filtrates revealed that A. alternata causing black spot of European pear produced AM-toxin I, known as a host-specific toxin of the A. alternata apple pathotype. AM-toxin I induced veinal necrosis on leaves of Le Lectier and General Leclerc cultivars, both susceptible to the European pear pathogen, at 5?×?10?7 M and 10?6 M respectively, but did not affect leaves of resistant cultivars at 10?4 M. PCR analysis with primers that specifically amplify the AM-toxin synthetase gene detected the product of expected size in the pathogen. These results indicate that A. alternata causing black spot of European pear is identical to that causing Alternaria blotch of apple. This is the first report of European pear disease caused by the A. alternata apple pathotype. This study provides a multiplex PCR protocol, which could serve as a useful tool, for the epidemiological survey of these two diseases in European pear and apple orchards. 相似文献
100.
A stable Leifsonia xyli subsp. xyli GFP‐tagged strain reveals a new colonization niche in sugarcane tissues 下载免费PDF全文
M. C. Quecine T. M. Silva G. Carvalho S. Saito M. Mondin N. S. Teixeira‐Silva L. E. A. Camargo C. B. Monteiro‐Vitorello 《Plant pathology》2016,65(1):154-162
Ratoon stunting disease (RSD), caused by the bacterium Leifsonia xyli subsp. xyli (Lxx), is one of the most economically important diseases of sugarcane worldwide. Because knowledge on the interaction of Lxx with its host at the microscopic level is limited, the development of tools to monitor Lxx during the colonization process could shed new light on the processes that control disease development. In this investigation, a transformation protocol was optimized and a mutant Lxx strain engineered that stably expressed the gfp gene in sugarcane tissues. In vitro, the growth of the mutant did not differ from that of the wild type. Also, plants inoculated with both strains showed comparable growth and development when analysed 180 days after inoculation (dai). Fluorescence microscopy of roots, stalks, meristems and leaf tissues of Lxx‐GFP‐inoculated plants was performed at 180 dai. In the leaves, Lxx‐tagged cells were observed within the xylem vessels as has been described before but, in addition, they were found in a new niche within the host tissues, in the mesophyll and in the bundle sheath cells surrounding the vascular system. This finding indicates that Lxx is able to move from the xylem to the parenchyma of the leaf cells. This first report of an Lxx mutant expressing a heterologous gene revealed that colonization of sugarcane by this pathogen is not limited to the xylem vessels as commonly reported. 相似文献