全文获取类型
收费全文 | 299篇 |
免费 | 17篇 |
专业分类
林业 | 30篇 |
农学 | 54篇 |
基础科学 | 2篇 |
38篇 | |
综合类 | 15篇 |
农作物 | 31篇 |
水产渔业 | 4篇 |
畜牧兽医 | 110篇 |
园艺 | 6篇 |
植物保护 | 26篇 |
出版年
2021年 | 6篇 |
2020年 | 4篇 |
2018年 | 6篇 |
2017年 | 13篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 2篇 |
2013年 | 16篇 |
2012年 | 14篇 |
2011年 | 15篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 25篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 5篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1973年 | 2篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1967年 | 5篇 |
1966年 | 2篇 |
排序方式: 共有316条查询结果,搜索用时 15 毫秒
51.
52.
Vijay P. Kale Girish S. Joshi Parikshit B. Gohil Mukul R. Jain 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2009,38(3):361-366
Background: Fasting is an important preanalytical factor that may affect the interpretation of hematology and clinical biochemistry data in toxicology or pharmacology studies. Limited information is available on how the results may be affected by different durations of fasting. Objective: The purpose of this study was to assess the influence of fasting duration on clinical pathology results in male and female rats and to determine an optimum fasting time for preclinical studies. Methods: Male and female Wistar rats (10 each per group) were fasted for 0, 4, 8, 16, 24, and 48 hours. Changes in body weight and in the results of routine CBC and clinical chemistry analysis were evaluated by 1‐way ANOVA. Results: Body weight was significantly decreased by 4 hours of fasting in all rats, and hemoglobin concentration was significantly increased at 16 hours in male rats. Serum glucose and triglyceride concentrations in both sexes and cholesterol and high‐density lipoprotein‐C concentrations in female rats were also significantly decreased beginning at 16 hours. The creatinine concentration was increased in females after 16 hours of fasting. Serum alkaline phosphatase and alanine aminotransferase activities were significantly decreased after 8 hours in males and 16 hours in females. Conclusions: Fasting‐induced changes in clinical pathology results were consistent with hemoconcentration and altered nutrition and metabolic function. Most changes occurred at 16 hours, with minimal subsequent changes. Hence, a 16‐hour fasting duration may be recommended for preclinical studies involving clinical pathology measurements. 相似文献
53.
A 66 kDa adult Haemonchus contortus excretory/secretory (E/S) antigen was identified in Western blot by reaction with sera from the infected goats. The protein was purified from the adult worm extract and E/S products by anion exchange and ConA-Sepharose chromatography. The purified protein inhibited monocyte function in vitro as judged by decreased production of hydrogen peroxide and nitric oxide in the culture medium. The protein also caused proliferation of peripheral blood mononuclear cells. The absence of protein in the free living L3 larvae suggests that the expression of this protein coincides with the adaptation to the parasitic life. A correlation of antibody titre and worm burden was observed in the infected goats with higher antibody levels in high worm burdened animals. Anti-protein antibody caused loss of adult worm motility in vitro resulting in the death of the parasite. The fact that the protein is recognized by the host together with in vitro killing of adult parasites by antibodies makes this protein a promising candidate for vaccination trial. 相似文献
54.
Among the Dayak people in East Kalimantan, simpukng (“forest gardens”) are an important component of their traditional farming systems. Simpukng is managed secondary forests in which selected species of fruits, rattan, bamboo, timber and other plants are planted. While most are owned by families and passed down from one generation to the next, some are managed on a communal basis. Complex customary Dayak rules exist that control the use and inheritance of these forests that help to avoid over-exploitation of resources. There is clear gender division of labour among Dayak in the management of simpukng that provide a range of products – for household consumption and sale and for customary rituals – fruits, vegetables, medicines, fire wood, honey, rattan, bamboos, and timber. Local knowledge about the more highly valued species are discussed. These indigenous forest garden systems are currently under threat from large-scale mining and logging activities; conflicts between local and external agencies are unfortunately frequent. This paper examines the development and management of simpukng in four Dayak villages in East Kalimantan and their implications on sustainable management of natural resources, with particular emphasis on the role of local knowledge of some of the more highly valued species and the current challenges faced by these communities in maintaining their traditional agroforest management practices. 相似文献
55.
Socio-Economic and Scientific Impact Created by Whitefly-Transmitted,Plant-Virus Disease Resistant Tomato Varieties in Southern India
下载免费PDF全文
![点击此处可从《农业科学学报》网站下载免费的PDF全文](/ch/ext_images/free.gif)
John Colvin N Nagaraju Carlos Moreno-Leguizamon R M Govindappa T B Manjunatha Reddy SA Padmaja Neena Joshi Peter M Hanson Susan E Seal V Muniyappa 《农业科学学报》2012,11(2):337-345
Research carried out to assess the impact of open-pollinated Tomato leaf curl virus (ToLCV)-resistant tomatoes and hybrids on the livelihoods of resource-poor farmers in Southern India is described and discussed. Three high-yielding ToLCV-resistant tomato varieties were developed initially using conventional breeding and screening techniques involving inoculation by ToLCV-viruliferous whitefly, Bemisia tabaci. In 2003 and 2004, respectively, these varieties were released officially by the Karnataka State Seed Committee and the Indian Ministry of Agriculture through notification in the Gazette of India. From 2003 to 2005, eleven seed companies bought breeder seed of the ToLCV-resistant varieties and used them to begin breeding F1 hybrids from them. Socio-economic studies carried out to assess the benefits obtained from growing the ToLCV-resistant varieties found that farmers could gain up to 10 times the profit by growing the ToLCV-resistant varieties compared to the pre-existing ToLCV-susceptible varieties. Adoption of ToLCV-resistant tomatoes was also associated with reduced pesticide use. Extra income from tomato sales was prioritised by farmers to pay for children's education, better nutrition and medicines. In a joint effort with the commercial seed sector in India, a promotional field day was organised in 2007. As well as the three ToLCV-resistant varieties, 62 ToLCV-resistant hybrid tomatoes were exhibited during a farmer-field day by 17 commercial seed companies and several public institutes. Tomatoes with ToLCV-resistance are now grown widely in South India and seeds of the three open-pollinated varieties have been distributed to more than 12 countries. In 2007, a conservative estimate of the financial-benefit to cost of the research ratio was already more than 837:1. 相似文献
56.
Alexander M. Stuart Colin V. PrescottGrant R. Singleton Ravindra C. Joshi 《Crop Protection》2011,30(2):147-154
A survey of the knowledge, attitudes and practices (KAP) of 100 rice farmers and 50 coconut farmers was conducted in the coastal lowland agro-ecosystems of the Sierra Madre Biodiversity Corridor, Luzon, Philippines to identify current rodent management practices and to understand the extent of rat damage and the attitudes of farmers to community actions for rodent management. Pests were most commonly listed as one of the three most important rice and coconut production constraints. Other major crop production constraints were typhoons and insufficient water. Farmers consider rats to be the major pest of coconut and of rice during the wet season rice crop, with average yield losses of 3.0% and 13.2%, respectively. Rice and coconut farmers practised a wide range of rodent management techniques. These included scrub clearance, hunting and trapping. Of the 42 rice farmers and 3 coconut farmers that applied rodenticides to control rodents, all used the acute rodenticide, zinc phosphide. However, only ten rice farmers (23.8%) applied rodenticides prior to the booting stage and only seven farmers (15.6%) conducted pre-baiting before applying zinc phosphide. The majority of farmers belonged to farmer organisations and believed that rat control can only be done by farmers working together. However, during the last cropping season, less than a third of rice farmers (31.2%) applied rodent management as a group. In order to reduce the impact of rodents on the farmers of the coastal lowlands of the Sierra Madre Biodiversity Corridor, integrated management strategies need to be developed that specifically target the pest rodents in a sustainable manner, and community actions for rodent management should be promoted. 相似文献
57.
58.
研究了位于印度加瓦尔海平面(950~1100m)上的亚热带森林的再生生长状况。对生长在不同方位(东、西、北、南)研究地的植被进行了定量分析。研究结果表明:宽叶榆绿木(Anogeissus latifolia)的树木、幼树和幼苗层在研究地点的所有方位显生长优势。长叶松(Pinusroxburghii)和毛白杨(Terminalia tomentosa)的树木、小树在研究地点的北部显生长优势。树木层的最高(380株·ha-1)和最低密度(260株·ha-1)分别出现在南坡和北坡。幼树的最高(1790株·ha-1)和最低密度(970株·ha-1)分别出现在东坡和西坡。树木和灌木层的多样性分别为0.846~1.710和1.943-2.847。与其它种的相比较(4%~33%),宽叶榆绿木(Anogeissus latifolia)的相对剪枝强度较高(45%-57%),此种是在北坡中最重要的树种。目前研究表明,如果不合理开采继续进行,宽叶榆绿木(Anogeissus latifolia)就有可能被其他种代替,在树种的成分和森林重建方面会发生剧烈的变化。人类活动的压力,地理方位和土壤营养已引起了树种的成分和森林重建方面的变化。 相似文献
59.
The present work investigated the ability of inactive brown seaweed, Turbinaria conoides, to biosorb aluminum(III) and cadmium(II) ions in both single and binary systems. Initial experiments were undertaken to determine the influence of pH and biosorption isotherms of each metallic ion. Owing to the presence of carboxylic groups, T. conoides exhibited high uptake capacity towards Al(III) and Cd(II) through ion-exchange mechanism. In the case of Al(III), T. conoides exhibited maximum biosorption at pH 4 with a capacity of 2.37?mmol/g, whereas the highest Cd(II) biosorption occurred at pH 5 with a capacity of 0.96?mmol/g. For both metal ions, T. conoides exhibited fast kinetics. Several models were used to describe isotherm (Langmuir, Freundlich, Redlich-Peterson, and Toth) and kinetic (pseudo-first and pseudo-second order) data. Desorption and reuse of T. conoides biomass in three repeated cycles was successful with 0.1?M HCl as elutant. In binary systems, the presence of Cd(II) severely affected Al(III) uptake by T. conoides. Compared to single-solute systems, Al(III) uptake was reduced to 56% compared to only 27% for Cd(II). Based on the model parameters regressed from the respective monometal systems, multicomponent Langmuir and Freundlich models were used to predict binary (Al + Cd) system of which the multicomponent Freundlich model was able to describe with good accuracy. 相似文献
60.
Traditional seed management and genetic diversity in barley varieties in high-hill agro-ecosystems of Nepal 总被引:1,自引:0,他引:1
Jwala Bajracharya Anthony H. D. Brown Bal K. Joshi Dipak Panday Bimal K. Baniya Bhuwon R. Sthapit Devra I. Jarvis 《Genetic Resources and Crop Evolution》2012,59(3):389-398
Chawali and Lekali are two common farmer’s barley varieties or landraces in Jumla, Nepal (2,240–3,000 m) with small to bold
grains and wide adaptation from irrigated low lands to high hills. This study was undertaken to test whether features of the
traditional seed system can significantly influence the diversity of a crop and its conservation on-farm. In Jumla (high-hill),
the barley seed system is completely informal and is mainly from farmer to farmer. In the present study, the seed flows and
the pattern of genetic diversity in barley were investigated to detect differences between the two varieties and test the
divergence among populations of each variety These data suggested that Chawali, the more common variety, was less subject
to homogenising gene flow between farms than was Lekali. A total of 128 farming households were surveyed for seed supply information
and 128 populations for each landrace from two villages: Kartikswami and Talium were collected for SSR diversity analysis.
Some 92 SSRs were screened in an initial sample of 20 barley populations of both landraces and 2 improved varieties (LG-51
and Soluwa). Of the 81 SSRs that consistently amplified, only 15 SSRs (19%) were polymorphic with gene diversity values ranging
from 0.09 to 0.71. A medium to low diversity was detected among the landrace populations of barley varieties. Chawali populations
were less polymorphic within ecological groups, and more divergent between than were Lekail populations. This result accords
with Chawali having a more conservative local seed system. 相似文献