全文获取类型
收费全文 | 298篇 |
免费 | 19篇 |
专业分类
林业 | 41篇 |
农学 | 34篇 |
基础科学 | 15篇 |
32篇 | |
综合类 | 17篇 |
农作物 | 14篇 |
水产渔业 | 18篇 |
畜牧兽医 | 107篇 |
园艺 | 10篇 |
植物保护 | 29篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 5篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 12篇 |
2016年 | 10篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 19篇 |
2012年 | 13篇 |
2011年 | 13篇 |
2010年 | 21篇 |
2009年 | 21篇 |
2008年 | 14篇 |
2007年 | 11篇 |
2006年 | 10篇 |
2005年 | 3篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 5篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1966年 | 2篇 |
排序方式: 共有317条查询结果,搜索用时 187 毫秒
101.
Non-availability of a standardized rapid serodiagnostic test for quick and accurate diagnosis of Mycoplasma crocodyli (M. crocodyli) infection in crocodiles was the underlining reason for conducting the present study. An indirect enzyme-linked immunosorbent assay (iELISA) for the detection of antibodies (Ab) to M. crocodyli infection in crocodile sera was developed using sonicated antigen (Ag) and anti-crocodile conjugate. The iELISA test was optimised with different reagents and at different steps. A cut-off value of percent positive greater than or equal to 53.47% resulted in an estimated sensitivity and specificity of 85.67 and 100%, respectively. The developed iELISA could be used for detection of Abs to M. crocodyli infection in crocodiles and may enable to understand the transmission of the disease. 相似文献
102.
103.
Irrigation crop coefficients for lowland rice 总被引:1,自引:0,他引:1
Meteorological and lysimetric data for a period of nine years were used to develop crop coefficients for rice grown under lowland conditions in a sub-humid tropical climate in India. The estimated crop coefficients were found to be higher than those values recommended by FAO. A crop coefficient model with basal coefficient, moisture availability coefficient and surface wetness coefficient terms has been proposed and found suitable. On most counts, the moisture availability coefficient was found to be near unity and the wetness coefficient was found to be significant. The basal crop coefficients for lowland rice have also been presented for practical use with the proposed models. 相似文献
104.
There exist capabilities for analyzing the behavior of surface flow and the ultimate distribution of infiltrated water in furrow irrigation. The corresponding synthesis, i.e., the selection of appropriate combinations of inflow rates, cutoff times and length of furrow — design and management, currently not so well established, is treated herein. A design-management nomograph is proposed for free draining graded furrows. This is a plot of efficiency, time of cutoff and uniformity coefficient contours each given on a length-flow rate space adjacent to one another, for a furrow with given infiltration characteristics, flow geometry, slope, roughness and required depth of application. The nomograph can be used to determine the combinations of length, time of cutoff and flow rate that would yield in optimum combination of efficiency and uniformity. 相似文献
105.
106.
Alpana Kulhari Arun Sheorayan Navneet Saxena Chander Mohan Manisha Mangal Ashok Chaudhury Ashok K. Dhawan Rajwant K. Kalia 《Genetic Resources and Crop Evolution》2013,60(3):1173-1180
The oleo-gum resin of Commiphora wightii (Arn.) Bhandari, a pharmacologically important balsamiferous woody shrub, has been used in treating various ailments and disorders since ancient times (2000 B.C.) due to the presence of steroidal compound guggulsterone. Two bioactive isomers of guggulsterone, E and Z, are responsible for lipid- and cholesterol-lowering and anti-cancerous activities. Further, guggul has been approved as food supplement by US-FDA as well as Council of Europe. Indiscriminate harvest of C. wightii from wild with negligible conservation efforts has lead to its inclusion in IUCN assemblage of endangered plant species. For identification of high guggulsterone yielding ecotypes of C. wightii, using high-performance thin-layer chromatographic (HPTLC) analysis, stem samples were collected from 50 plants from eleven locations in arid tracts of Haryana, Gujarat and Rajasthan. Dried, powdered material was subjected to extraction with petroleum ether using soxhlet apparatus. Samples were spotted on precoated activated silica plates (60F-254) and were developed using toluene–acetone (9:1 v/v) as mobile phase. The analysis was carried out in the absorbance mode at 250 nm using HPTLC scanner. The regression analysis data for the calibration plots for E and Z guggulsterone showed good linear relationship with R2 = 1 and 0.9897, respectively. Highest concentration of guggulsterone E (284 μg/g dry wt) was found in the accession collected from Palana, Bikaner whereas highest guggulsterone Z concentration (89.5 μg/g dry wt) was found in the accession collected from CAZRI, Jodhpur. 相似文献
107.
Murali Mohan Sabbavarapu Mamta Sharma Siva Kumar Chamarthi Nayakoti Swapna Abhishek Rathore Mahendar Thudi Pooran Mal Gaur Suresh Pande Sarvjeet Singh Livinder Kaur Rajeev Kumar Varshney 《Euphytica》2013,193(1):121-133
Fusarium wilt (FW) and Ascochyta blight (AB) are two important diseases of chickpea which cause 100 % yield losses under favorable conditions. With an objective to validate and/or to identify novel quantitative trait loci (QTLs) for resistance to race 1 of FW caused by Fusarium oxysporum f. sp. ciceris and AB caused by Ascochyta rabiei in chickpea, two new mapping populations (F2:3) namely ‘C 214’ (FW susceptible) × ‘WR 315’ (FW resistant) and ‘C 214’ (AB susceptible) × ‘ILC 3279’ (AB resistant) were developed. After screening 371 SSR markers on parental lines and genotyping the mapping populations with polymorphic markers, two new genetic maps comprising 57 (C 214 × WR 315) and 58 (C 214 × ILC 3279) loci were developed. Analysis of genotyping data together with phenotyping data collected on mapping population for resistance to FW in field conditions identified two novel QTLs which explained 10.4–18.8 % of phenotypic variation. Similarly, analysis of phenotyping data for resistance to seedling resistance and adult plant resistance for AB under controlled and field conditions together with genotyping data identified a total of 6 QTLs explaining up to 31.9 % of phenotypic variation. One major QTL, explaining 31.9 % phenotypic variation for AB resistance was identified in both field and controlled conditions and was also reported from different resistant lines in many earlier studies. This major QTL for AB resistance and two novel QTLs identified for FW resistance are the most promising QTLs for molecular breeding separately or pyramiding for resistance to FW and AB for chickpea improvement. 相似文献
108.
109.
R. Yadav K. Mohan V. Kumar M. Sarkar K. Nitu H.H.D. Meyer B.S. Prakash 《Domestic animal endocrinology》2013
A highly sensitive enzyme immunoassay (EIA) that used the second antibody coating technique and the cortisol-horseradish peroxidase conjugate as a label for determination of free and total cortisol in blood plasma of dairy animals (cows, buffaloes, and goats) was developed. For biological validation of the EIA, blood samples were collected from the animals at 48 and 24 h before and 0, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, and 132 h after dexamethasone administration. The EIA was performed directly with 20 μL of fresh plasma (for free cortisol) and also with 20 μL of heat-treated plasma (for total cortisol) after 1:5 dilutions with PBS. Cortisol standards ranging from 0.39 to 200 pg/well/20 μL were used, and the sensitivity of the EIA procedure was found to be 0.39 pg/well/20 μL, which corresponded to 0.02 ng/mL. In comparison with RIA the EIA was at least 4 times more sensitive and required 5 times less cortisol antiserum. In female cattle, buffaloes, and goats, the total, free, and bound plasma cortisol before dexamethasone administration was significantly (P < 0.05) higher than the total, free, and bound cortisol after dexamethasone administration. It can be concluded from these studies that the direct, sensitive EIA validated for estimating the free and total cortisol concentrations was sufficiently reliable and quick for studying the dynamics of cortisol distribution in blood plasma of dairy animals. 相似文献
110.
Madan Mohan Dey Mohammed A. Rab Ferdinand J. Paraguas Somying Piumsombun Ramachandra Bhatta Md Ferdous Alam 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1-2):89-111
ABSTRACT This paper discusses fish consumption and preference patterns for fish species by income groups, and by urban/rural divide in Bangladesh, China, India, Indonesia, the Philippines, Thailand, and Vietnam. The analysis is based on primary data collected by the WorldFish Center and its partner institutes by means of a survey of 5,931 households in the selected countries. The FAO database and other published materials were also used to analyze trends in fish consumption. Freshwater fish species constitute a major share in total per capita fish consumption in most of these countries. Pelagic and demersal marine fish are the main contributor to per capita total fish consumption in the countries with longer coastal boundaries (such as Indonesia, the Philippines and Thailand), and in the coastal regions within each country. Results suggest that fish contributes between 15% and 53% of the total animal protein intake in these countries. Fish consumption varies widely with economic position of the households, in terms of both per capita consumption and type of fish species. Per capita fish consumption increases with increase in income. The share of fish protein in total animal protein expenditure is higher for lower income groups, demonstrating their dependence on fish as a source of animal protein. Poor people consume mostly low-price fish and rich people spend a significant portion of their fish budget on expensive fish. Per capita fish consumption is substantially higher in rural areas than in urban areas. 相似文献