全文获取类型
收费全文 | 261篇 |
免费 | 5篇 |
国内免费 | 2篇 |
专业分类
林业 | 35篇 |
农学 | 9篇 |
基础科学 | 2篇 |
22篇 | |
综合类 | 4篇 |
农作物 | 6篇 |
水产渔业 | 44篇 |
畜牧兽医 | 131篇 |
园艺 | 6篇 |
植物保护 | 9篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 4篇 |
2014年 | 10篇 |
2013年 | 15篇 |
2012年 | 16篇 |
2011年 | 20篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 12篇 |
2007年 | 16篇 |
2006年 | 15篇 |
2005年 | 25篇 |
2004年 | 14篇 |
2003年 | 19篇 |
2002年 | 17篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1981年 | 2篇 |
1972年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有268条查询结果,搜索用时 31 毫秒
11.
ABSTRACT: The nucleotide sequences of Japanese flounder Paralichthys olivaceus , major histocompatibility complex (MHC) cDNA, classical MHC class Iα, non-classical MHC class Iβ, MHC class IIα and IIβ, were determined. The domain structures and antigen binding motifs of vertebrate MHC are conserved in the Japanese flounder MHC. A phylogenetic analysis supports the classification of these genes into class I and class II MHC. Classical MHC class Iα was ubiquitously expressed, whereas the non-classical MHC class Iβ was expressed mainly in lymphoid organs, gills, intestine and stomach. The MHC classes IIα and IIβ were also ubiquitously expressed. 相似文献
12.
Ikuo Ota 《Small-Scale Forestry》2002,1(1):25-37
About 80% of annual wood fiber consumption in Japan is imported. Even though most of the land surface is covered by forests
in Japan, the domestic forestry and forest industry are threatened by such imports flooding the local market. Fragmented land
ownership, steep terrain, rapid growth of weeds, and high labor costs have all contributed to the decline of domestic forestry.
Further, the purchasing power of the Japanese Yen has become very strong in recent years, and the decreasing prices of imported
timber have depressed the prices of domestic timber, eroding profitability and discouraging small-scale forestry. In spite
of these difficult circumstances, there are several interesting new developments in Japanese forestry. One is the revision
of the Basic Forestry Law of 1964, through which the Japanese government is steering forest policy from timber production towards environmental services.
Because of this change, new ways to assist rural forestry activities will become available in the near future. Another change
is the certification movement, where recent examples of Japanese companies acquiring ISO 14001 and Forest Stewardship Council
(FSC) forest certifications provide hope to depressed domestic forestry activities. In particular, FSC group certification
is useful in motivating small-scale forest owners to implement and maintain sustainable forestry practices.
This paper is based on the presentation at IUFRO Group 3.08.00 Symposium at Joensuu, Finland 2001. The original article, ‘The
economic situation of small-scale forestry in Japan’, is in Niskanen and Vayrynen (2001). 相似文献
13.
Ikuo Ota 《Small-Scale Forestry》2006,5(1):111-125
Yusuhara Forest Owners’ Cooperative (YFOC) in Kochi Prefecture in Japan received its forest management certification from
the Forest Stewardship Council (FSC) in 2000. YFOC is recognised as the resource manager of its members’ forests, and they
were the first organisation to gain such certification in Japan. With the continuous efforts of selling FSC certified wood
in the domestic housing construction market, YFOC has substantially increased their timber sales in recent years. It is a
noteworthy event in Japanese small-scale forestry, which has been struggling with declining economic performance for many
years. This paper analyses the detail of forestry activities and changes which occurred in YFOC after certification by FSC.
An interesting effect of increasing economic performance is found to have come from an unexpected direction. It is concluded
that the FSC certification system is a possible tool to revitalise Japanese small-scale forestry as well as obtain favourable
environmental outcomes. 相似文献
14.
Anatomical variations in wood among four native species of Leguminosae grown in arid areas of China 总被引:1,自引:0,他引:1
Yang Shu-min Jiang Ze-hui Ren Hai-qing Ikuo Furukawa 《中国林学(英文版)》2007,9(1):39-44
Morphological features and anatomical variations are described and illustrated in detail for four native species of Legumi-nosae grown in arid sandy regions in China, which are Hedysarum scoparium Fisch.et Mey., Caragana korshiskii Kom., Lespedeza bicolor Turcz. and Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f. All species showed similar morphological features: distinct growth ring boundaries, ring to semi-ring-porosity, simple perforation plates, alternate intervessel pitting, nonseptate fibers, para... 相似文献
15.
FURUKAWA Ikuo 《中国林业科技(英文版)》2006,5(2):22-27
INTRODUCTION The larger genus in Polygonaceae is Calligonum, which includes about 100 species of shrubs that grow in central Asia. It is well suited to arid climates with drought resistance, and grows more on clay, sandy and gravel grounds. These plants are often cultivated as ornamentals and a stabilizer of mobile sand dunes. There was published information on the wood anatomy of all the examined genera in Polygonaceae (Ma 1994), but the selected species have not yet been described. Ad… 相似文献
16.
Policies Affecting Forestry Entrepreneurship 总被引:1,自引:0,他引:1
Anssi Niskanen Anders Lunnan Ikuo Ota Keith Blatner John Herbohn Lyndall Bull Ian Ferguson Gordon M. Hickey 《Small-Scale Forestry》2007,6(3):233-255
Many demand and supply-side policies impede or foster forestry entrepreneurship. A study was conducted to consolidate existing knowledge on policies influencing forestry entrepreneurship
in Finland, Norway, Japan, Australia, the Philippines and the USA, and to draw conclusions on these impeding and fostering
factors. From the country studies it was difficult to find common structures on policies affecting forestry entrepreneurship.
This is understandable because most policies in forestry are aimed at supporting sustainable forest management, wood production
and ecological services of the forests rather than entrepreneurship as such. Despite the high variety of policies applied
in the study countries, it can be concluded that strict public control on forests’ use and management potentially impedes
forestry entrepreneurship. While these policies assist to correct market failure and to promote sustainability of forest management,
they may also result into unnecessary and ineffective regulations that limit the opportunities for forestry entrepreneurship.
A common feature promoting the demand for forestry entrepreneurship in some of the countries studied is the strong emphasis
on forestry cooperatives, which were important institutions to support small-scale forestry entrepreneurship. In many study
countries, different ad hoc programs are implemented to find new economic and entrepreneurial opportunities aside from the
current use of wood and forests. Subsidies and tax incentives are commonly applied to reduce risks from making forestry investments
or otherwise increase the economic return from timber production. 相似文献
17.
18.
Quantitative determination of cyproconazole by gas chromatography–mass spectrometry (GC/MS) analysis was investigated. The results suggest that cyproconazole determination is significantly affected by wood extracts. In the presence of methanol extracts of Japanese cedar (Cryptomeria japonica) heartwood, cyproconazole showed 50 % larger peak area than that without the extracts. This phenomenon whereby contaminants in the sample solution affect the intensity of the peak signal is known as the matrix effect. An investigation for eliminating the matrix effect revealed that adding sorbitol as an analyte protectant drastically increased the analyte peak intensity and successfully mitigated the matrix effect of the wood extracts. Adding hexaconazole as an internal standard was also useful in reducing the deviation of the data. The efficacy of a novel sample preparation method consisting of adding sorbitol and hexaconazole as analyte protectants and the internal standard, respectively, were applied to the GC/MS analysis of cyproconazole in the presence of wood extracts of the other nine species. It is revealed that cyproconazole can be precisely determined by GC/MS analysis in combination with the analyte protectant and the internal standard. 相似文献
19.
Summary Ninety Chinese rice landraces were examined with special reference to the indica-japonica differentiation in terms of traditional criteria, isozyme analysis and PCR analysis of the chloroplast DNA (cpDNA). Cultivars were separated into indica and japonica defined by a discriminant function (Z) based on key characters, as well as by isozyme genotypes. Most indica landraces had chloroplast DNAs with a deletion at the Pst-12 fragment, while most japonica landraces had cpDNAs without the deletion. Two traditionally recognized varietal groups in China, keng and hsien, corresponded largely to the respective japonica and indica revealed in our study. The results obtained in this study showed good agreement for classification of indica and japonica types by the three methods: discriminant analysis by Z value, isozyme analysis, and PCR analysis for cpDNA. 相似文献
20.
Levels of active oxygen species are controlled by ascorbic acid and anthocyanin in Arabidopsis 总被引:1,自引:0,他引:1
Nagata T Todoriki S Masumizu T Suda I Furuta S Du Z Kikuchi S 《Journal of agricultural and food chemistry》2003,51(10):2992-2999
Stabilization of the levels of active oxygen species (AOS) is important to the survival of organisms. To clarify the system controlling levels of AOS in plants, this study used an electron spin resonance (ESR) method to directly measure superoxide radical (O(2)(.-)) scavenging activities in the wild-type Arabidopsis thaliana (Col and Ler ecotypes), two anthocyanin mutants (tt3 and ttg1), and an ascorbic acid mutant (vtc1). Under ordinary growth conditions, Arabidopsis contained superoxide-scavenging activity (SOSA) of approximately 300-500 SOD units/g of fresh weight. The ESR pattern indicated that most (40-50%) of this activity was due to ascorbic acid. For the analysis of SOSA under conditions of oxidative stress, synthesis of AOS was induced by gamma-irradiation. The radical scavenging activity in irradiated plants increased approximately 10-fold following an associated increase in the accumulation of ascorbic acid and anthocyanin. The accumulation of ascorbic acid and anthocyanin was suppressed by treatment with an antioxidant before irradiation and was induced by treatment with a radical-generating reagent. The contributions of ascorbic acid and anthocyanin to the total superoxide radical scavenging activity differed among ecotypes. In the Ler ecotype, ascorbic acid accumulated at twice the level of that in the Col ecotype, and induction of anthocyanin was half that in Col. To confirm the activity of ascorbic acid and anthocyanin against AOS stress, the viability of the wild type and mutants (tt2, tt3,tt5, ttg1, and vtc1) was examined after gamma-irradiation. Only the plants in which ascorbic acid and anthocyanin were induced had the ability to grow and flower. 相似文献