全文获取类型
收费全文 | 621篇 |
免费 | 50篇 |
专业分类
林业 | 62篇 |
农学 | 11篇 |
基础科学 | 2篇 |
180篇 | |
综合类 | 45篇 |
农作物 | 42篇 |
水产渔业 | 60篇 |
畜牧兽医 | 186篇 |
园艺 | 20篇 |
植物保护 | 63篇 |
出版年
2024年 | 3篇 |
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 33篇 |
2020年 | 38篇 |
2019年 | 26篇 |
2018年 | 29篇 |
2017年 | 29篇 |
2016年 | 37篇 |
2015年 | 26篇 |
2014年 | 31篇 |
2013年 | 44篇 |
2012年 | 41篇 |
2011年 | 52篇 |
2010年 | 24篇 |
2009年 | 19篇 |
2008年 | 28篇 |
2007年 | 26篇 |
2006年 | 29篇 |
2005年 | 27篇 |
2004年 | 36篇 |
2003年 | 21篇 |
2002年 | 22篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1989年 | 1篇 |
1986年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1977年 | 1篇 |
1975年 | 3篇 |
1964年 | 1篇 |
排序方式: 共有671条查询结果,搜索用时 31 毫秒
21.
Detection and characterization of a rhabdovirus causing mortality in black bullhead catfish,Ameiurus melas
下载免费PDF全文
![点击此处可从《Journal of fish diseases》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Giulia Bedendo Valentina Panzarin Andrea Fortin Gianpiero Zamperin Tobia Pretto Alessandra Buratin Rosita Quartesan Matteo Sabbion Cristian Salogni Francesco Pascoli Anna Toffan 《Journal of fish diseases》2018,41(7):1063-1075
This study fully describes a severe disease outbreak occurred in 2016 in black bullhead catfish farmed in Italy. Affected fish showed nervous clinical signs as well as emaciations and haemorrhagic petechiae on the skin at the fin bases, abdomen and gills. Viral isolation in cell culture allowed the subsequent identification of a rhabdovirus, tentatively named ictalurid rhabdovirus (IcRV), through electron microscopy, immunofluorescence and whole genome sequencing (WGS). The newly isolated virus, together with 14 additional viral strains stored in our repository and detected during similar mortality episodes in the period 1993–2016, was phylogenetically analysed on the basis of the nucleoprotein and the glycoprotein nucleotide and amino acid sequences. The genetic distances among Italian IcRV strains were also estimated. Our results show that all the IcRV strains belong to the genus Sprivivirus and are closely related to the tench rhabdovirus (TenRV). Italian catfish production is constantly decreasing, mainly due to viral infections, which include the newly characterized IcRV. Data presented in this work will assist to investigate the molecular epidemiology and the diffusive dynamics of this virus and to develop adequate surveillance activities. 相似文献
22.
ABSTRACTInvasive alien plant species (IAPs) represent one of the main biological threats to biodiversity worldwide. Information about their phenotypic plasticity are needed to increase awareness about their future invasive potential. A study about phenotypic plasticity in response to contrasting light regimes and its quantification by a plasticity index (PI) of two IAPs (Ailanthus altissima and Robinia pseudoacacia) inside a Strict Nature Reserve was conducted. R. pseudoacacia showed a 70% higher PI, with a strongly greater value at morphological leaf level, associated with a greater ability to survive and grow in forest understory, explaining its greater widespread. Otherwise, A. altissima showed its highest PI at physiological level, which was associated with the ability to colonize and grow in environments with high-light regimes. Based on these results, the conservative management has limited the presence of A. altissima by its lower ability to grow in forest understory. In fact, the small-scale gaps in the forest infrastructure, that could allow its recruitment, are originated only from the death of a single tree or small group of trees. Regarding R. pseudoacacia, it is critical to maintain this type of management because any disturbances resulting in large openings could further promote its presence inside the Reserve. 相似文献
23.
24.
The methanol and ethyl acetate extracts of the aerial parts of Cirsium tenoreanum, have been evaluated for their phytochemical constituents and antibacterial and cytotoxic properties. Three flavonoids, apigenin, quercetin-3-O-galactoside and kaempferol-3-O-ramnoside, were isolated. The ethyl acetate extract showed a good antiproliferative activity. 相似文献
25.
Valentina De Monte Francesco Staffieri Domenico Caivano Antonello Bufalari 《Acta veterinaria Scandinavica》2015,57(1)
A three-month-old female Rottweiler puppy was referred for intravascular correction of a previously identified cor triatriatum dexter. Echocardiography confirmed the presence of a hyperechoic membrane that divided the right atrium into a cranial and caudal chamber. A foramen in this membrane allowed the blood to flow from the caudal to the cranial chamber. Balloon dilation of the defect under transthoracic echocardiographic guidance was scheduled for the following day. The dog was premedicated with 0.5 μg/kg sufentanil and 0.2 mg/kg midazolam administered intravenously. General anaesthesia was induced with 2 mg/kg propofol and maintained with inhaled isoflurane in oxygen; at the same time, a constant rate infusion of 0.5 μg/kg/h sufentanil was administered by means of an infusion pump. Uneventful ventricular and supraventricular tachyarrhythmias developed during the placement of catheters and balloon dilation. At the end of procedure, when the guide wire and balloon catheter were removed, normal sinus rhythm was observed. To the authors’ knowledge, no previous reports have described the anaesthetic management of a balloon dilation procedure for cor triatriatum dexter in dogs. 相似文献
26.
27.
Pasqualone A Montemurro C Summo C Sabetta W Caponio F Blanco A 《Journal of agricultural and food chemistry》2007,55(10):3857-3862
Collina di Brindisi is an Italian extra virgin olive oil that obtained the mark of protected designation of origin (PDO) according to EC Regulation 2081/92. The varietal requirements of the official production protocol of this oil foresee that this oil is prepared from cultivar Ogliarola (minimum 70%) and other Olea europaea L. cultivars that are diffused in the production area, accounting for a maximum of 30%. The aim of this work was to verify the effectiveness of microsatellite analysis in verifying the identity of Collina di Brindisi PDO olive oil. A preliminary assessment of product's quality by means of chemical analyses was also carried out. Microsatellite analysis clarified that the generic name Ogliarola, indicated in the technical sheet of this PDO oil, actually corresponded to the Ogliarola salentina cultivar. Furthermore, the obtained results showed that the examination of a limited number of DNA microsatellites enables the identification of the Ogliarola salentina cultivar in this PDO oil. 相似文献
28.
Patui S Peresson C Braidot E Tubaro F Colussi A Bonnländer B Macrì F Vianello A 《Journal of agricultural and food chemistry》2007,55(20):8223-8230
In this paper lipoxygenase (LOX) presence was investigated in coffee berries to determine its involvement in lipid degradative metabolism of plants grown in organic and conventional cultivations. An immunochemical analysis has evidenced a ca. 80 kDa protein, cross-reacting with an anti-LOX antibody, only in the pulp fraction of berries obtained from plants of both cultivations. LOX activity in this fraction could be monitored either as conjugated diene formation or reaction products (determined by HPLC) and was mainly associated with a heavy membrane fraction (HMF, enriched in tonoplast, endoplasmic reticulum, plasma membrane, and mitochondria) and a light membrane fraction (LMF, enriched in plasma membrane and endoplasmic reticulum, with low levels of tonoplast and mitochondria). The LOX activity of LMF from berries of both cultivations showed an optimum at pH 8.0. The HMF exhibited a different activity peak in samples from conventional (pH 8.0) and organic (pH 5.5) cultures, suggesting the presence of different isoenzymes. These findings were also confirmed by variation of the ratio of 9- and 13-hydroperoxides in organic (1:1) and conventional cultivations (1:10), indicating that the organic one was subjected to an oxidative stress in the coffee pulp fraction leading to the expression of an acidic LOX. Such de novo synthesized LOX activity could be responsible for the production of secondary metabolites, which may interfere with the organoleptic profile of coffee. 相似文献
29.
Marzia Bo Martina Coppari Federico Betti Francesco Enrichetti Marco Bertolino Francesco Massa Simone Bava Guido Gay Riccardo Cattaneo-Vietti Giorgio Bavestrello 《水产资源保护:海洋与淡水生态系统》2021,31(3):543-566
- Seamounts host some of the most important deep-sea ecosystems. The unique environmental characteristics of seamounts sustain rich biological hot spots, which, in recent times, have suffered the effects of intense fishing pressure.
- Biodiversity and vulnerability data are extremely scarce for Mediterranean seamounts, and this, in addition to the complex socio-economic and juridical status of offshore sites, results in difficulty in identifying the best management strategies.
- An extensive remotely operated vehicle (ROV) survey was used to characterize the megabenthic assemblages of the summits of two upper bathyal seamounts, Ulisse and Penelope (Ligurian Sea, north-west Mediterranean Sea). The biogeographic implications of these findings and the possible environmental factors favouring the occurrence of these communities are discussed.
- High densities of abandoned, lost, or otherwise discarded fishing gear (mainly longlines) and a reduction in the average size of the fragile and slow-growing habitat-forming gorgonian Callogorgia verticillata indicate the occurrence of high levels of anthropogenic impacts on the summit regions, which are fishing grounds for artisanal and recreational fishers.
- The recovery of fishing data describing the first catches in the 1970s proved to be useful in inferring the short- and long-term effects of fishing practices in these previously unexploited offshore areas. In particular, the local extinction of demersal top predators, subjected to exceptional catches nearly 50 years ago, highlights the slow recovery rate of such species.
- Criteria defining vulnerability are discussed for the two study areas, and specific conservation actions, including the creation of regulated protected areas, are proposed.
30.
Veronica Redaelli Domenico Bergero Enrica Zucca Francesco Ferrucci Leonardo Nanni Costa Lorenzo Crosta Fabio Luzi 《Journal of Equine Veterinary Science》2014
This review of the use of thermographic technique in equines introduces the principles upon which infrared radiation and thermoregulatory physiology are based and describes the instrumentation used and its practical use. The advantage of this imaging technique is that it is a noninvasive thermographic examination, both from an operational (the animal and the operator) and health (no penetrating radiation is used) standpoint. Advantages and disadvantages of this technique, equine applications, and physiological assessments are discussed. 相似文献