全文获取类型
收费全文 | 873篇 |
免费 | 47篇 |
国内免费 | 2篇 |
专业分类
林业 | 32篇 |
农学 | 39篇 |
基础科学 | 5篇 |
141篇 | |
综合类 | 116篇 |
农作物 | 47篇 |
水产渔业 | 33篇 |
畜牧兽医 | 436篇 |
园艺 | 15篇 |
植物保护 | 58篇 |
出版年
2023年 | 5篇 |
2021年 | 16篇 |
2020年 | 20篇 |
2019年 | 21篇 |
2018年 | 16篇 |
2017年 | 19篇 |
2016年 | 14篇 |
2015年 | 11篇 |
2014年 | 14篇 |
2013年 | 42篇 |
2012年 | 35篇 |
2011年 | 41篇 |
2010年 | 37篇 |
2009年 | 17篇 |
2008年 | 36篇 |
2007年 | 42篇 |
2006年 | 40篇 |
2005年 | 43篇 |
2004年 | 34篇 |
2003年 | 40篇 |
2002年 | 53篇 |
2001年 | 19篇 |
2000年 | 19篇 |
1999年 | 23篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 5篇 |
1995年 | 11篇 |
1994年 | 10篇 |
1992年 | 12篇 |
1991年 | 16篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 7篇 |
1980年 | 5篇 |
1979年 | 8篇 |
1978年 | 8篇 |
1977年 | 7篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1943年 | 5篇 |
排序方式: 共有922条查询结果,搜索用时 963 毫秒
31.
Conor G. McAloon Michael L. Doherty Henry O’Neill Michael Badminton Eoin G. Ryan 《Irish veterinary journal》2015,68(1)
An unusual case of an 11-month-old, black Limousin-cross heifer, with an 8-month history of episodic seizures and photosensitisation, was referred by a veterinary practitioner to the Farm Animal Section of the UCD Veterinary Hospital, School of Veterinary Medicine, University College Dublin, Ireland, in August 2014. Following an investigation, a diagnosis of Bovine Congenital Erythropoietic Protoporphyria (BCEPP) was made. To the authors’ knowledge this is the first report of such a case in Ireland. BCEPP should be considered as a differential diagnosis in young animals displaying periodic seizures and/or photosensitisation.
Electronic supplementary material
The online version of this article (doi:10.1186/s13620-015-0044-3) contains supplementary material, which is available to authorized users. 相似文献32.
33.
Cardozo Ernesto Gómez Celentano Danielle Rousseau Guillaume Xavier Silva Hulda Rocha e Muchavisoy Henry Mavisoy Gehring Christoph 《Agroforestry Systems》2022,96(5-6):941-956
Agroforestry Systems - The potential of agroforestry systems (AFS) for atmospheric carbon sequestration in degraded tropical lands is of key interest for climate change and rural development... 相似文献
34.
Ruscoe Wendy A. Brown Peter R. Henry Steve van de Weyer Nikki Robinson Freya Hinds Lyn A. Singleton Grant R. 《Journal of pest science》2022,95(1):493-503
Journal of Pest Science - The advent of ‘conservation agriculture’ (CA) farming using zero- or no-tillage practices and an accompanying change in crop rotations in the last... 相似文献
35.
The gross anatomical structure of the ringed seal (Pusa hispida) gastrointestinal tract is poorly described and often veterinary anatomical terminology is not used. Although the basic abdominal visceral pattern corresponded to domestic carnivores, significant differences were noted. The stomach was an elongated sharply bent tube (u‐shaped) with the pylorus and fundus juxtaposed. The elongated jejunum measured up to 15.6 times body length and had 37 jejunal arteries from the cranial mesenteric artery. The pancreas was asymmetrical with a small right lobe and a large left lobe. The unusually short greater omentum negated formation of deep and superficial leaves. The most remarkable difference was the separation of the liver parenchyma into three physically separate masses, held together by hepatic ducts, veins and arteries. The topography and position of the liver was dependent on the amount of blood in the hepatic sinus (distended hepatic veins and hepatic portion of vena cava). Thus, as the hepatic sinus filled, the lateral liver masses separate from the central mass by moving caudolaterally. This was facilitated by modified coronary and triangular ligaments which did not attach directly to the liver, but instead to the hepatic sinus. These anatomical adaptations are apparently advantageous to ringed seal's survival in a deep marine environment. 相似文献
36.
37.
D Priya NL Selokar AK Raja M Saini AA Sahare N Nala P Palta MS Chauhan RS Manik SK Singla 《Reproduction in domestic animals》2014,49(2):343-351
The objective of this study was to explore the possibility of producing wild buffalo embryos by interspecies somatic cell nuclear transfer (iSCNT) through handmade cloning using wild buffalo somatic cells and domestic buffalo (Bubalus bubalis) oocytes. Somatic cells derived from the ear skin of wild buffalo were found to express vimentin but not keratin and cytokeratin‐18, indicating that they were of fibroblast origin. The population doubling time of skin fibroblasts from wild buffalo was significantly (p < 0.05) higher, and the cell proliferation rate was significantly (p < 0.05) lower compared with that of skin fibroblasts from domestic buffalo. Neither the cleavage (92.6 ± 2.0% vs 92.8 ± 2.0%) nor the blastocyst rate (42.4 ± 2.4% vs 38.7 ± 2.8%) was significantly different between the intraspecies cloned embryos produced using skin fibroblasts from domestic buffalo and interspecies cloned embryos produced using skin fibroblasts from wild buffalo. However, the total cell number (TCN) was significantly (p < 0.05) lower (192.0 ± 25.6 vs 345.7 ± 42.2), and the apoptotic index was significantly (p < 0.05) higher (15.1 ± 3.1 vs 8.0 ± 1.4) for interspecies than that for intraspecies cloned embryos. Following vitrification in open‐pulled straws (OPS) and warming, although the cryosurvival rate of both types of cloned embryos, as indicated by their re‐expansion rate, was not significantly different (34.8 ± 1.5% vs 47.8 ± 7.8), the apoptotic index was significantly (p < 0.05) higher for vitrified–warmed interspecies than that for corresponding intraspecies cloned embryos (48.9 ± 7.2 vs 23.9 ± 2.8). The global level of H3K18ac was significantly (p < 0.05) lower in interspecies cloned embryos than that in intraspecies cloned embryos. The expression level of HDAC1, DNMT3a and CASPASE3 was significantly (p < 0.05) higher, that of P53 was significantly (p < 0.05) lower in interspecies than in intraspecies embryos, whereas that of DNMT1 was similar between the two types of embryos. In conclusion, these results demonstrate that wild buffalo embryos can be produced by iSCNT. 相似文献
38.
Jude Akamu Ewunkem ;Louis Ernest Ndiva Jackai ;Henry Osofuhene-Sintim ;Beatrice Nuck Dingha 《农业科学与技术》2014,(7):585-596
Cowpea (Vigna unguiculata L. Walp.) and tomato (Lycopersicum esculentum L. Karst) are attacked by a wide range of insect pests worldwide. In many cases, pesticides are used to control the pests. In 2010 and 2011, we conducted field experiments to evaluate and compare the effectiveness of a biorational (Agroneem~) and conventional pesticide (imidacloprid or thiamethoxam) on insect pests of these crops. In the first year, two varieties of cowpea (Mississippi Silver and Pinkeye Purple Hull) and two of tomato (Mariana and German Johnson) were used; in the second year, the better performing of each group (Mississippi Silver and Mariana) were used for the study. A split-plot design with four replications in Year 1, and a randomized complete block design with six treatment combinations in Year 2. In the first year, both pesticide groups were applied following manufacturer's recommendation (10-14 d cycles); and in the second year, the application of the pesticides was driven by economic thresholds level (ETL) of insect pests. The most prevalent species of insects recorded in both crops were in the families: Chrysomelidae, Pentatomidae, Cicadellidae, Vespidae, Sarcophagidae, Thripidae and Sphingidae. In both years, the diversity of insects on cowpea was greater than on tomato and more insects were observed in the second year compared to the first, despite the absence of significant difference (P 〉 0.05) between varieties in the treated plots. The yield of cowpea and tomato was comparable in all sprayed plots. 相似文献
39.
Egbert W. Henry Jeffrey W. Miller Lauren J. Dungy Michael T. Johnson Julia K. Yeekpeh 《Journal of plant nutrition》2013,36(4):353-373
It is usually assumed that plant tissue responses to nutritional elements are due to specific genetic differences that may exist either between inbred or closely related species. Little Marvel (dwarf) and Alaska (normal) varieties of 14‐day old pea seedlings were treated with four different concentrations of Al‐containing nutrient solution (0.0mM, 0.2mM, 0.6mM and distilled H2O), prior to being exposed for 14 days to either DARK, LIGHT, or UV. Selected tissues (root tip, main root, main stem and proximal stem) were bioassayed for peroxidase and polyphenol oxidase enzyme activities, fresh wt vs. dry wt, water uptake and stem growth. The present study suggests that Little Marvel and Alaska pea tissue responds to high toxicity levels of Al by demonstrating an enhancement of enzymic activity. Tissue weight, growth and water uptake also show differential tissue specificity in both Little Marvel and Alaska tissue, in terms of Al toxicity response, given a particular external exposure. 相似文献
40.