全文获取类型
收费全文 | 362篇 |
免费 | 21篇 |
国内免费 | 1篇 |
专业分类
林业 | 42篇 |
农学 | 19篇 |
基础科学 | 1篇 |
60篇 | |
综合类 | 24篇 |
农作物 | 23篇 |
水产渔业 | 53篇 |
畜牧兽医 | 99篇 |
园艺 | 22篇 |
植物保护 | 41篇 |
出版年
2024年 | 3篇 |
2023年 | 3篇 |
2022年 | 14篇 |
2021年 | 14篇 |
2020年 | 10篇 |
2019年 | 16篇 |
2018年 | 18篇 |
2017年 | 21篇 |
2016年 | 13篇 |
2015年 | 11篇 |
2014年 | 10篇 |
2013年 | 45篇 |
2012年 | 19篇 |
2011年 | 19篇 |
2010年 | 16篇 |
2009年 | 13篇 |
2008年 | 15篇 |
2007年 | 7篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 5篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 4篇 |
1969年 | 1篇 |
1967年 | 3篇 |
1946年 | 1篇 |
排序方式: 共有384条查询结果,搜索用时 15 毫秒
31.
32.
The article shows results of an international and interdisciplinary project with the title ‘Rainfall and its Erosivity in
Ethiopia’. Rainfall variability affects the water resource management of Ethiopia. The influence of rainfall variability on
flow regimes was investigated using five gauging stations with data availability from 1982–1997. It was confirmed that the
variability in rainfall has a direct implication for surface runoff. Surface runoff declined at most of the gauging stations
investigated. Therefore, effective water resource management is recommended for the study area. Future research should focus
on watershed management which includes land-use and land cover. The question posed here is whether the variability in rainfall
significantly affected surface flow in the study area. 相似文献
33.
34.
35.
Ataseven VS Oğuzoğlu TÇ Başaran-Karapınar Z Bilge-Dağalp S 《Research in veterinary science》2012,92(2):324-326
Equine adenovirus type 1 (EAdV-1) is a cause of repiratory tract infection in equids. In present study for the first time in Turkey, the prevalence of EAdV-1 in nasal swab samples obtained from horses showing respiratory symptoms was investigated by polymerase chain reaction (PCR), and molecular characterization of the hexon gene detected in the Turkish (TR) strain was performed. Overall, the prevalence of EAdV-1 was found low (1.4%) as indicated by a positive PCR reaction from the nasal swab extracts tested. Phylogenetic analysis based on the partial sequences of the hexon gene of a TR-EAdV-1 strain with those of previously isolated AdVs from different mammals and an EAdV-1 M1 strain showed that the EAdV-1 strains were placed into a unique cluster. Although the TR-EAdV-1 strain was closely related to CAV-1, CAV-2 and bat adenovirus reference strains, larger-scale studies are necessary to better understand the molecular epidemiology and population structure of EAdV-1 in Turkey. 相似文献
36.
The efforts to mitigate CO2, one of the greenhouse gases causing global warming and climate change problems, have an important place in the worldwide agenda. One of the factors that cause CO2 emissions is energy use in residential buildings, hence urban residential use is one of the areas on which mitigation efforts are focused. As land use planning determines the spatial development, density and form of residential areas, it has a direct role in the formation of residential emissions. However, these efforts to mitigate emissions could not yet be integrated with land use planning. It is possible to list the reasons as the mitigation efforts are made either on the building scale (mitigation of residential emissions by technological–architectural solutions) or on a global–regional scale (development of carbon sinks), the focus on transportation sector, and in land use planning, lack of considering the potential of urban green areas to mitigate emissions. By taking into consideration the O2 production potential of green areas, a method proposal for land use planning is developed in this study to maintain the carbon–oxygen balance in residential areas. Depending on the form and density of the residential areas developed in a plan, the necessary size of green areas in such a plan is estimated by the method proposed. The varying emission amounts in different residential areas with diverse housing types, the number of actively used residential units, and local vegetation differences are included in the estimate. Therefore, an estimation method proposal that could be easily used in land use planning and that considers local differences is presented in the paper. 相似文献
37.
Effect of two species of cyanobacteria as biofertilizers on some metabolic activities, growth, and yield of pea plant 总被引:1,自引:0,他引:1
Mohamed Elanwar H. Osman Mostafa M. El-Sheekh Amal H. El-Naggar Saly F. Gheda 《Biology and Fertility of Soils》2010,46(8):861-875
Two cyanobacterial species (Nostoc entophytum and Oscillatoria angustissima) were tested as biofertilizers, substituting the normally used chemical fertilizer, for pea plant. Inoculation of soil with a suspension of each species or a combination of the two species significantly increased the germination percentage and stimulated the other measured growth parameters and photosynthetic pigment fractions of pea. However, the soil inoculation with one cyanobacterial species and the addition of the recommended dose or half the recommended dose of chemical fertilizer were usually more effective and also increased carbohydrate and protein contents of produced pea seeds. However, biofertilization combined with half the recommended dose of the chemical fertilizer was usually more effective than the addition of the full rate of the chemical fertilizer, and this may allow saving 50% of the used chemical fertilizer. The protein profile of the produced seeds showed appearance and disappearance of some protein bands in response to fertilization treatments compared to the control. Blue green algae analyses show that N. entophytum fixed more N, produced more exopolysaccharide, and contained more auxin and cytokinin than O. angustissima, the latter contained more gibberellins. These data may explain their different influences on growth and yield of pea. 相似文献
38.
Hatice Şelale Ibrahim Çelik Visam Gültekin Jens Allmer Sami Doğanlar Anne Frary 《Plant Breeding》2013,132(3):344-351
All publicly available opium poppy expressed sequence tag (EST) sequences, totalling 20 885, were assembled into unigenes and examined for simple sequence repeats (SSRs). Nearly 19% of the 14 957 unigenes contained SSRs with 4% harbouring more than one SSR. Average density of the SSRs was 1 SSR per 3.6 kb of non‐redundant EST sequence. Trinucleotide SSRs were most frequently identified (39%), and many of the most prevalent motifs were AT‐rich. Flanking primers were designed for 86% of the SSRs and 67 primer pairs were tested on 37 opium poppy accessions and seven related species. All markers were transferable to the related species. Polymorphism information content (PIC) values for the markers were intermediate for comparisons within opium poppy (average of 0.27) and slightly higher for comparisons across species (average of 0.29). The markers were found to be useful for diversity analysis as they successfully distinguished among Turkish opium poppy accessions and land races. 相似文献
39.
Hakan Basak K. Mesut Çimrin Metin Turan Ekrem Ozlu 《Communications in Soil Science and Plant Analysis》2019,50(3):350-361
Mycorrhiza has attracted interest as one of the microorganisms that increase a crop’s salt stress tolerance. This study was conducted to determine the impacts of mycorrhiza inoculation and applying salt at different ratios on the yield of peppers and amino acid concentrations. The study was conducted in greenhouse conditions on loamy soils with four salt treatments, two mycorrhiza inoculations and a control in a complete randomized block design. The present study indicated that salt treatment alone was significantly correlated with crop stem and root amino acid concentrations, RWC% and leaf sizes, whereas applying mycorrhiza showed a positive relationship to stem height, stem and root wet weight, and root amino acids but led to a decloine in root serine and glutamine, and stem amino acid and glutamine. In conclusion, inoculating with mycorrhiza was observed to make a positive contribution to salt stress tolerance at different levels in almost all the parameters examined. 相似文献
40.
AGPT and HA tests were employed for rapid diagnosis of PPRV infection in sheep and goats in Sudan. Forty lymph nodes and spleen
samples from suspected cases of PPR in both sheep and goats were examined by AGPT and HA tests for detection of PPRV antigen.
Viral antigen was detected from (77.5%) of the samples tested by AGPT and (92.5%) tested by HA test. The results of both tests
revealed that HA test was more sensitive than AGPT for detection of PPRV antigen (Kappa statistics 0.4366). Another advantage
of the HA test over AGPT was that it can differentiate PPRV from RPV. Thus the HA test represents a quick, easy, simple, cheap
and reliable confirmatory test for the diagnosis of PPR and differential diagnosis of PPRV and RPV. The HA test was carried
out using chicken, goat and pig RBCs. Chicken RBCs were found to be the most sensitive for detection of PPRV antigen, followed
by goat then pig RBCs. The HA time when using chicken RBCs was 20–25 minutes, using goat RBCs was 25–30 minutes and using
pig RBCs was 40–45 minutes. The distribution of PPR infection in four different regions of Sudan was investigated. 相似文献