全文获取类型
收费全文 | 268篇 |
免费 | 14篇 |
专业分类
林业 | 29篇 |
农学 | 7篇 |
48篇 | |
综合类 | 7篇 |
农作物 | 18篇 |
水产渔业 | 28篇 |
畜牧兽医 | 83篇 |
园艺 | 3篇 |
植物保护 | 59篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 11篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 18篇 |
2011年 | 17篇 |
2010年 | 14篇 |
2009年 | 16篇 |
2008年 | 21篇 |
2007年 | 19篇 |
2006年 | 15篇 |
2005年 | 9篇 |
2004年 | 11篇 |
2003年 | 3篇 |
2002年 | 8篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有282条查询结果,搜索用时 31 毫秒
151.
Antonio Saracino Angelo Rita Sergio Rossi Laia Andreu-Hayles Gerhard Helle Luigi Todaro 《European Journal of Forest Research》2017,136(1):27-36
Developing long-term chronologies of tree-ring anatomical features to evaluate climatic relationships within species might serve as an annual proxy to explore and elucidate the climatic drivers affecting xylem differentiation. Pinus leucodermis response to climate was examined by analyzing vertical xylem resin ducts in wood growing at high elevation in the Apennines of peninsular Southern Italy. Early- and latewood tree-ring resin duct chronologies, spanning the 1804–2010 time period, were constructed. We analyzed the relationships between resin duct chronologies and climate over the last century using correlation and response function analyses. Overall, results showed that ring width and resin duct relationships differed between early- and latewood, which indicated conditions affecting growth were not associated with resin duct production. Results also revealed differential responses to climate between early- and latewood resin duct chronologies. A notable observation was a positive and stable relationship between latewood resin duct number chronology and July maximum temperature throughout the twentieth century. This result suggested resin ducts might be a suitable proxy to evaluate P. leucodermis response to climate in the study area. 相似文献
152.
Angelo Nolè Angelo Rita Agostino Maria Silvio Ferrara Marco Borghetti 《Annals of Forest Science》2018,75(3):83
Key message
A remote sensing-based approach was implemented to detect the effect of a late spring frost on beech forests in the Mediterranean mountain region. The analysis of spatio-temporal variability of frost effects on normalised difference vegetation index (NDVI) highlighted the distribution of the canopy damage across the forest according to geomorphic factors such as slope, aspect, and altitude.Context
Increased intensity and frequency of extreme temperatures such as late spring frosts and heat waves represent the main drivers affecting forest ecosystem structure and composition in the Mediterranean region.Aims
The main objective of this study was to evaluate the effects of a late spring frost disturbance, which occurred during spring 2016 in southern Italy, through the assessment of the spatial pattern of the damage to the beech forest canopy associated with the peak decrease in normalised difference vegetation index (NDVI), and the analysis of the NDVI temporal recovery after this frost disturbance.Methods
The forest areas affected by frost were detected through the NDVI differencing technique based on Landsat 8 (OLI/TIRS) imagery time series. The influence of local geomorphic factors (i.e., aspect, elevation, and slope) on forest NDVI patterns was assessed by means of a generalized additive model (GAM).Results
A rather counterintuitive NDVI patterns emerged according to the forest exposition, with NDVI significantly higher on the north facing areas than the southerly ones. The main canopy damage occurred at about 1250 m and reached up to 1500 m asl, representing the altitudinal range affected by the frost disturbance. Finally, the full canopy recovery occurred within 3 months of the frost event.Conclusion
The analysis of seasonal Landsat 8 image time series related to local geomorphic factors, such as aspect, slope, and altitude, and plant phenology on a frost event date, contributed to highlight the NDVI spatio-temporal variation and canopy recovery of a Mediterranean mountain beech forest.153.
This study was undertaken by simulating the effects of increasing the temperature and CO2 values on the incidence and severity of F. equiseti on wild rocket (Diplotaxis tenuifolia) and radish (Raphanus sativus), under phytotron conditions. Two sets of 3 trials were carried out in which eight different temperature and CO2 combinations were tested:1) 400–450 ppm CO2, 18–22 °C; 2) 800–850 ppm CO2, 18–22 °C; 3) 400–450 ppm CO2, 22–26 °C, 4) 800–850 ppm CO2, 22–26 °C, 5) 400–450 ppm CO2, 26–30 °C; 6) 800–850 ppm CO2, 26–30 °C; 7) 400–450 ppm CO2, 14–18 °C; 8) 800–850 ppm CO2, 14–18 °C. The temperature and CO2 levels were significant factors of influence on disease incidence (DI) and severity (DS) in all the trials, and their combination significantly influenced the DI and DS of F. equiseti leaf spot on both hosts. Disease incidence and severity increased on wild rocket at 850 ppm of CO2, in comparison to 450 ppm, in each tested temperature range. The highest CO2 value on radish, for all the tested temperature regimes, caused an increase in DI and DS, which resulted statistically significant at the highest tested temperature range. The results obtained in this study add more concern to the possible negative effects of the spread of F. equiseti on vegetables in Italy as well as in other areas suffering from increased temperatures as a consequence of climate changes. 相似文献
154.
Toxicity to and egg‐laying avoidance of Drosophila suzukii (Diptera: Drosophilidae) caused by an old alternative inorganic insecticide preparation 下载免费PDF全文
155.
Gennaro Riccio Genoveffa Nuzzo Gianluca Zazo Daniela Coppola Giuseppina Senese Lucia Romano Maria Costantini Nadia Ruocco Marco Bertolino Angelo Fontana Adrianna Ianora Cinzia Verde Daniela Giordano Chiara Lauritano 《Marine drugs》2021,19(8)
Sponges are known to produce a series of compounds with bioactivities useful for human health. This study was conducted on four sponges collected in the framework of the XXXIV Italian National Antarctic Research Program (PNRA) in November-December 2018, i.e., Mycale (Oxymycale) acerata, Haliclona (Rhizoniera) dancoi, Hemimycale topsenti, and Hemigellius pilosus. Sponge extracts were fractioned and tested against hepatocellular carcinoma (HepG2), lung carcinoma (A549), and melanoma cells (A2058), in order to screen for antiproliferative or cytotoxic activity. Two different chemical classes of compounds, belonging to mycalols and suberitenones, were identified in the active fractions. Mycalols were the most active compounds, and their mechanism of action was also investigated at the gene and protein levels in HepG2 cells. Of the differentially expressed genes, ULK1 and GALNT5 were the most down-regulated genes, while MAPK8 was one of the most up-regulated genes. These genes were previously associated with ferroptosis, a programmed cell death triggered by iron-dependent lipid peroxidation, confirmed at the protein level by the down-regulation of GPX4, a key regulator of ferroptosis, and the up-regulation of NCOA4, involved in iron homeostasis. These data suggest, for the first time, that mycalols act by triggering ferroptosis in HepG2 cells. 相似文献
156.
da Silva Aline Priscilla Gomes Spricigo Poliana Cristina Purgatto Eduardo de Alencar Severino Matias Jacomino Angelo Pedro 《Plant foods for human nutrition (Dordrecht, Netherlands)》2019,74(3):358-363
Plant Foods for Human Nutrition - The aim of the present study was to identify volatile organic compounds (VOCs) by SPME-GC and quantify the bioactive compounds (ascorbic acid, total flavonoids and... 相似文献
157.
Maria Rosaria Panuccio Teresa Papalia Emilio Attinà Angelo Giuffrè 《Archives of Agronomy and Soil Science》2019,65(5):700-711
Nowadays, the recycling of organic wastes represents a key factor for improving soil and crop quality with socio-economic and environmental benefits. In recent years, the production of digestate significantly increased with a crescent need to be sustainable disposal. The use of digestate as soil amendment has been widely studied but few researches evaluated the digestate effects on crop quality. Since it has been proven that digestate increased soil fertility, we hypothesized that it could increase crop quality as organic fertilizers do. To verify this hypothesis, we analyzed the effects of two digestates on Cucumber quality. Cucumber was chosen because it is an important old crop used worldwide as fresh food, and in cosmetic and pharmaceutic industries. Results showed that digestates increased its content of phenols and flavonoids with antioxidant activity. Neohesperidine and hesperitin with well-known antioxidant, anti-inflammatory and anti-carcinogenic properties as well as naringin and narirutin with the power of reducing the risk of atherosclerosis and cardiovascular complications were manifested only in digestate amended cucumbers. These results highlighted the potentiality of digestates not only as crop growth promoter but also as phytochemical inducers representing a good option for the production of high-quality food with reduced chemical mineral fertilizer inputs. 相似文献
158.
Polyploidy is widespread in plants and has played a major role in the evolution and diversification of the plant kingdom.
Unreduced (2n) gametes are an interesting tool for polyploidisation and the creation of genetic variation in plant breeding.
Especially in ornamentals, polyploidisation can broaden attractive features within a species. A Begonia collection was screened on the occurrence of 2n pollen with the aid of four different techniques: pollen size measurement,
flow cytometric analysis of nuclei isolated from germinated and non germinated pollen, investigation of the microsporogenesis
and analysis of progeny. In ten of the 70 screened genotypes (B. dregei, B. pearcei, B. ‘Anna Christina’, B. ‘Bubbles’, B. ‘Florence Rita’, B. ‘Orococo’, B. ‘Rubaiyat’, B. ‘Spatflacier’, B. ‘Tamo’ and B276), large pollen were observed with a rather spherical than normal ellipsoidal shape. Flow cytometric data
proved that these aberrantly shaped pollen were associated with 2n ploidy levels, although they were not always viable. Meiotic
aberrations in these large pollen producers resulted mainly in dyads although also monads, triads and polyads were observed.
Successful crosses were obtained with B. dregei, B. ‘Orococo’, and B276 as pollinators; DNA content had increased in all or a part of the progeny. The results show that the
occurrence of 2n pollen is not a rare phenomenon in Begonia. 相似文献
159.
160.
Felizzola CR Martins MT Stopiglia A de Araújo NS de Sousa SO 《Journal of veterinary dentistry》2003,20(2):79-83
Three young, female dogs were operated for compound odontoma. All tumors were considered stage III with treatment consisting of partial mandibulectomy or maxillectomy. Microscopic examination of the resected tissue confirmed the diagnosis. Relatively aggressive, resective surgery resulted in prolonged tumor-free intervals. 相似文献