全文获取类型
收费全文 | 91篇 |
免费 | 5篇 |
专业分类
林业 | 12篇 |
农学 | 13篇 |
13篇 | |
综合类 | 8篇 |
农作物 | 2篇 |
水产渔业 | 10篇 |
畜牧兽医 | 31篇 |
园艺 | 2篇 |
植物保护 | 5篇 |
出版年
2021年 | 2篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 7篇 |
2006年 | 4篇 |
2005年 | 10篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1978年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有96条查询结果,搜索用时 19 毫秒
1.
We investigated the validity and efficiency of a survey using sight per unit effort (SPUE) of sika deer and shrub-layer decline
rank (SDR), which is an index of decline in the physical structure of a whole stand caused by sika deer, based on data collected
on a broad scale. This survey was to be used to manage a deer population in order to conserve a forest ecosystem. First, we
evaluated the spatial and temporal scales of deer density that are most appropriate for predicting decline in the status of
understory vegetation. The model with SPUE calculated in a buffer with a radius of 4.5 km using data for the past 4 years
was found to be the best. We showed that our knowledge of the relationship between deer density and status of shrub-layer
vegetation is improved by identifying the most suitable spatial and temporal scales of SPUE for predicting SDR. Next, we quantified
the effects of SPUE and environmental components on SDR in stands. We found that SPUE had the greatest effect on SDR among
all explanatory variables. Moreover, the area under the curve (AUC) was large in a model that only used SPUE (AUC = 0.718).
This result suggests that the variation in SDR among stands was explained well by SPUE regardless of differences in the forest
environment. Furthermore, we identified the effective values of SPUE for preventing shrub-layer vegetation from declining
through deer density control. We conclude that a management system based on SPUE and SDR is a simple and valid method for
managing deer populations in order to conserve forest ecosystems. 相似文献
2.
Summary A light microscopic (LM) visual technique to determine the polyethylenimine (PEI) distribution in a wood-PEI composite was studied by the adsorption of acid red or the circulation of Cu(II) ion with PEI in the composite. The amount of the adsorbed dye or Cu(II) on the composite increased linearly with an increase in the PEI content of the wood-PEI. The dyed composites were observed with LM under monochromatic light, corresponding to their absorption maxima at 560 nm for acid red and at 640 nm for copper chelate. The microscopic image was photographically recorded and the negative was subjected to densitometric analysis. At a polymer content lower than 4% in the composite, about 70% of total polymer was located in the middle lamella region, leaving only 30% in the secondary wall. With increasing PEI content of the composite, the concentration in the secondary wall increased, and about 80% of the polymer was located in the secondary wall at a PEI content of 27%. There were no noticeable differences between the amount of polymer detected by dyeing with acid red and by chelating with Cu(II). From the results of the line analysis of the intensity of the characteristic X-ray of uranium, the distribution of the PEI in the cell wall agreed closely with that determined by the LM method. It was concluded that the LM visual technique to determine the PEI location in the wood-PEI composite by dyeing with acid red or by chelating with Cu(II) is a simple and reliable method. 相似文献
3.
Kyotaro Noguchi Tadashi Sakata Takeo Mizoguchi Masamichi Takahashi 《Journal of Forest Research》2005,10(6):435-441
Fine roots are a key component of forested ecosystems, but available information is still limited. This study examined the
production and mortality of fine roots less than 1 mm in diameter in a Japanese cedar (Cryptomeria japonica D. Don) plantation located on the Kanto Plain in central Japan. We used a minirhizotron technique in combination with soil
coring, and collected data for 1 year (May 2002–May 2003). Fine root production and mortality were determined from changes
in the lengths of individual fine roots on minirhizotron tubes. Both fine root production and mortality rates were greater
in the upper soil than in lower soil levels. Both rates were seasonal, with higher values in summer than in winter; this trend
was more pronounced in upper soil levels. These results suggest that environmental conditions, such as temperature or soil
properties, affect the production and mortality rates of fine roots. Fine root production and mortality occurred simultaneously,
and their rates were similar, which may have led to unclear seasonal changes in fine root standing crop estimates. Soil coring
indicated that the fine root biomass of this stand was about 120 g m−2, of which 40% was from Japanese cedar. The estimated rates of dry matter production and mortality of total fine roots, including
understory plants, were both approximately 300 g m−2 year−1. 相似文献
4.
Tien‐Chun Wan Yu‐Tse Liu Lan‐Tyi Duann Kuo‐Hui Yu Chih‐Ming Chen Liang‐Chuan Lin Ryoichi Sakata 《Animal Science Journal》2014,85(1):75-80
The purposes of this study were to assess the improvement of fatty liver induced by ethanol with animal liver and bile extracts. This research aimed to increase the economic values of animal liver and bile extracts and used these to reduce damage of ethanol‐induced fatty liver. Extracts came from animal liver and bile, including pig bile powder, pig liver extract, a mixture of pig bile powder and pig liver extract, chicken bile powder, chicken liver extract, and a mixture of chicken bile powder and chicken liver extract, and these were fed to Long‐Evans rats. The results showed that rats fed ethanol for long terms could increase values of aspartate transaminase, cholesterol, γ‐glutamy‐transferase and alkaline phosphatase. Pig bile powder could decrease the values of aspartate transaminase, cholesterol and γ‐glutamy‐transferase. The significances also decreased on aspartate transaminase, γ‐glutamy‐transferase and aspartate transaminase, which were carried out with the pig liver extract treatment. These results suggest pig bile and liver extracts have high potential to improve rats' ethanol‐induced fatty liver with serum biochemical parameters. 相似文献
5.
Summary The potential of isozymes for distinguishing asparagus varieties was carried out by a survey on 21 varieties using 10 enzyme systems: GOT, SkDH, DIA, PGM, MDH, IDH, PGD, ACP, PGI, MR and ADH. Only 3 enzymes, SkDH, GOT and PGM, showed useful polymorphisms. The varieties were found heterogeneous according to their genetic structure: open pollinated varieties were more heterogeneous than clonal hybrids; the F1 hybrid and the vitroclones were homogeneous. As expected from the narrow genetic basis of the varieties, only a few alleles per isozyme locus were present. Moreover, for each enzyme, one allele or type was predominant so that the discriminating power of the method was low. However some of the varieties could be identified and different applications of the results are presented.Abbreviations D.U.S.-
Distinction-Uniformity-Stability
- ACO-
aconitase
- ACP-
acid phosphatase
- ADH-
alcohol dehydrogenase
- CAT-
catalase
- DIA-
diaphorase
- END-
endopeptidase
- GOT-
glutamate oxaloacetate transaminase
- IDH-
isocitrate dehydrogenase
- MDH-
malate dehydrogenase
- MR-
menadione reductase
- PGI-
phosphoglucoisomerase
- PGM-
phosphoglucomutase
- PGD-
phosphoglucose dehydrogenase
- POX-
peroxidase
- SkDH-
shikimate dehydrogenase 相似文献
6.
Three rhesus monkeys which had been isolated from social contact during their first year of life persistently overate and overdrank during adulthood. These monkeys ingested approximately twice as much fluid and food as the control animals reared normally. 相似文献
7.
Pang PT Teng HK Zaitsev E Woo NT Sakata K Zhen S Teng KK Yung WH Hempstead BL Lu B 《Science (New York, N.Y.)》2004,306(5695):487-491
Long-term memory is thought to be mediated by protein synthesis-dependent, late-phase long-term potentiation (L-LTP). Two secretory proteins, tissue plasminogen activator (tPA) and brain-derived neurotrophic factor (BDNF), have been implicated in this process, but their relationship is unclear. Here we report that tPA, by activating the extracellular protease plasmin, converts the precursor proBDNF to the mature BDNF (mBDNF), and that such conversion is critical for L-LTP expression in mouse hippocampus. Moreover, application of mBDNF is sufficient to rescue L-LTP when protein synthesis is inhibited, which suggests that mBDNF is a key protein synthesis product for L-LTP expression. 相似文献
8.
Taguchi H Watanabe S Temmei Y Hirao T Akiyama H Sakai S Adachi R Sakata K Urisu A Teshima R 《Journal of agricultural and food chemistry》2011,59(8):3510-3519
Shrimp and crab are well-known as allergenic ingredients. According to Japanese food allergy labeling regulations, shrimp species (including prawns, crayfishes, and lobsters) and crab species must be differentially declared when ≥10 ppm (total protein) of an allergenic ingredient is present. However, the commercial ELISA tests for the detection of crustacean proteins cannot differentiate between shrimp and crab. Therefore, two methods were developed to discriminate shrimp and crab: a shrimp-PCR method with postamplification digestion and a crab-PCR method that specifically amplifies a fragment of the 16S rRNA gene. The sensitivity and specificity of both PCR methods were verified by experiments using DNA extracted from 15 shrimp species, 13 crab species, krill, mysid, mantis shrimp, other food samples (cephalopod, shellfish, and fish), incurred foods, and commercial food products. Both PCR methods could detect 5 pg of DNA extracted from target species and 50 ng of genomic DNA extracted from incurred foods containing 10 ppm (μg/g) total protein of shrimp or crab. The two PCR methods were considered to be specific enough to separately detect species belonging to shrimp and crab. Although false-positive and false-negative results were obtained from some nontarget crustacean species, the proposed PCR methods, when used in conjunction with ELISA tests, would be a useful tool for confirmation of the validity of food allergy labeling and management of processed food safety for allergic patients. 相似文献
9.
Seasonal variation in pigmentation and anthocyanidin phenetics in commercial Eustoma flowers 总被引:2,自引:0,他引:2
A. F. M. Jamal Uddin Fumio Hashimoto Toshiki Miwa Katsuhiro Ohbo Yusuke Sakata 《Scientia Horticulturae》2004,100(1-4):103-115
The seasonal change in petal color and pigmentation of 29 commercial Eustoma cultivars was studied. The flowers are basically divided into four groups according to the major anthocyanidin phenotype in association with petal coloration, i.e., delphinidin (Dp)-based (purple flower), cyanidin (Cy)-based (reddish purple flower), pelargonidin (Pg)-based (pink flower), and none (white flower) groups. The constitution of petal anthocyanidins was not changed by forcing treatment in most of the flowers. Lightness (L*) and chroma (C*, color saturation) showed a change along with the increase/decrease of hue angle difference (ΔH*), thus simultaneously the chromatic tonalities tended to move to redder and bluer, respectively. Floral pigment clustering described two flower groups in a dendrogram, based on anthocyanidin constitutions as phenetic markers, which are apparently the Dp- and Pg-based phenotypes of anthocyanidin syntheses. The Cy-based flowers made a subcluster with the Pg-based flowers, indicating a close relationship in the biosynthesis of the two anthocyanidins, and suggesting the Dp- and Pg-syntheses complement one another. 相似文献
10.
Izumi Noguchi Takunori Katoh Shigekatsu Sakai Riki Iwata Masayuki Akiyama Hideyuki Ohtsuka Kouichi Sakata Hirohide Aga Yutaka Matsumoto 《Water, air, and soil pollution》2001,130(1-4):421-426
Snowcover surveys were carried out in Hokkaido, northern Japan. Snowpack samples were collected using a steel pipe at 80 sites in 1988, 69 sites in 1992, and 66 sites in 1996 and 2000 during the time when the water equivalents of the snowcover are the greatest. Spatial distribution maps of water equivalents and of the concentrations and the accumulated amounts of hydrogen, non-sea-salt sulfate and non-sea-salt calcium ion of the snowcover drawn by Kriging method are discussed. The distribution maps show that water equivalents and the accumulated amounts of hydrogen and non-sea-salt sulfate in all the sample years were largest in the Japan Sea region, as were the ion concentrations of hydrogen and non-sea-salt sulfate. It was estimated this was caused by air pollutants transported from a great distance. The ratio of areas below pH 5.0 increased temporally from 1988 (20%) to 1992, 1996 and 2000 (66–80%). This trend was estimated to be affected by a decline of non-sea-salt calcium concentrations derived from alkaline road dust. In addition, the effect of snowcover components was assessed by comparison between the acid loads of the snowcover and the acid neutralizing capacity of lake water. We found that lakes in the middle of the Japan Sea coast have the potential to be acidified by snowmelt. 相似文献