全文获取类型
收费全文 | 594篇 |
免费 | 36篇 |
专业分类
林业 | 29篇 |
农学 | 19篇 |
基础科学 | 8篇 |
120篇 | |
综合类 | 39篇 |
农作物 | 20篇 |
水产渔业 | 40篇 |
畜牧兽医 | 297篇 |
园艺 | 13篇 |
植物保护 | 45篇 |
出版年
2024年 | 6篇 |
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 20篇 |
2020年 | 23篇 |
2019年 | 22篇 |
2018年 | 22篇 |
2017年 | 19篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 21篇 |
2013年 | 31篇 |
2012年 | 45篇 |
2011年 | 46篇 |
2010年 | 29篇 |
2009年 | 32篇 |
2008年 | 41篇 |
2007年 | 48篇 |
2006年 | 33篇 |
2005年 | 32篇 |
2004年 | 28篇 |
2003年 | 25篇 |
2002年 | 19篇 |
2001年 | 2篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1978年 | 1篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1941年 | 1篇 |
排序方式: 共有630条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
Weak effects of habitat type on susceptibility to invasive freshwater species: an Italian case study
下载免费PDF全文
![点击此处可从《水产资源保护:海洋与淡水生态系统》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Angela Boggero Alberto Basset Martina Austoni Enrico Barbone Luca Bartolozzi Isabella Bertani Alessandro Campanaro Antonella Cattaneo Fabio Cianferoni Giuseppe Corriero Ambrosius Martin Dörr A. Concetta Elia Gentile Francesco Ficetola Lyudmila Kamburska Gianandrea La Porta Sara Lauceri Alessandro Ludovisi Elda Gaino Enzo Goretti Massimo Lorenzoni Marina Manca Aldo Marchetto Giuseppe Morabito Francesco Nonnis Marzano Alessandro Oggioni Cataldo Pierri Nicoletta Riccardi Giampaolo Rossetti Nicola Ungaro Pietro Volta Silvia Zaupa Diego Fontaneto 《水产资源保护:海洋与淡水生态系统》2014,24(6):841-852
- 相似文献
75.
Nicola Grint BVSc DVA Diplomate ECVAA MRCVS & Alexandra Dugdale MA Vet MB DVA Diplomate ECVAA MRCVS 《Veterinary anaesthesia and analgesia》2009,36(1):63-66
Objective To compare the brightness of South American camelid venous blood to that of Equidae.
Study design Prospective clinical evaluation.
Animals Twelve South American camelids (eight llamas, four alpacas), eight horses and ponies (control group).
Methods Appropriately sized catheters were placed in the jugular vein of each animal under local anaesthesia. The blood spilt before the catheter was capped was caught on a white tile. A sample of blood was drawn for blood-gas analysis. The brightness of the blood (both on the tile and in the syringe) was matched to a colour chart (1 = darkest red, 8 = brightest red) by a single observer under bright light conditions. Packed cell volume (PCV) and partial pressure of oxygen (PvO2 ) in the blood were also measured on the syringe blood. Normally distributed data were compared using a two tailed t -test, and non-normally distributed data were compared using a Mann–Whitney U -test. Significance was set at p < 0.05.
Results Camelid venous blood was significantly brighter red than that of horses and ponies both on the white tile ( p = 0.0003) and in the syringe ( p = 0.0001). PCV was significantly lower in camelids (32 ± 4%) compared with horses (37 ± 5%). Partial pressure of oxygen values were similar between groups.
Conclusions and clinical relevance Jugular venous blood in alpacas and llamas is significantly brighter red than that of horses. Colour should not be used as a sole determinant of venous or arterial catheterization in this species. 相似文献
Study design Prospective clinical evaluation.
Animals Twelve South American camelids (eight llamas, four alpacas), eight horses and ponies (control group).
Methods Appropriately sized catheters were placed in the jugular vein of each animal under local anaesthesia. The blood spilt before the catheter was capped was caught on a white tile. A sample of blood was drawn for blood-gas analysis. The brightness of the blood (both on the tile and in the syringe) was matched to a colour chart (1 = darkest red, 8 = brightest red) by a single observer under bright light conditions. Packed cell volume (PCV) and partial pressure of oxygen (PvO
Results Camelid venous blood was significantly brighter red than that of horses and ponies both on the white tile ( p = 0.0003) and in the syringe ( p = 0.0001). PCV was significantly lower in camelids (32 ± 4%) compared with horses (37 ± 5%). Partial pressure of oxygen values were similar between groups.
Conclusions and clinical relevance Jugular venous blood in alpacas and llamas is significantly brighter red than that of horses. Colour should not be used as a sole determinant of venous or arterial catheterization in this species. 相似文献
76.
77.
Nicola Rooney Samantha Gaines Elly Hiby 《Journal of Veterinary Behavior: Clinical Applications and Research》2009,4(3):127-134
Research conducted by the Anthrozoology Institute and the Defence Science and Technology Laboratory has shown that many working dogs exhibit high levels of physiologic stress in response to kenneling (Hiby et al., 2006, Rooney et al., 2007a). Furthermore, these dogs tend to perform poorly during training, establishing links between welfare and working ability (Rooney et al., 2005, Rooney et al., 2007b). Subsequently, we have been studying how kenneling affects welfare and working ability. Specifically, we have investigated which elements within housing and husbandry influence welfare, which of these seem to be the most important, and how environmental enrichment (e.g. feeding devices) can affect welfare and working ability. This paper draws together results from all of these studies, identifying signs that may be indicative of compromised welfare, and providing guidelines, based on scientific evidence, for how to improve kenneled working dog welfare. It reproduces an unpublished guide designed to primarily inform and advise practitioners who are responsible for caring for, and/or handling working dogs. This paper aims to ensure that practitioners are updated of the most recent advances in working dog welfare, and hence many of the studies summarized here are yet to be published in full, in peer-reviewed journals. 相似文献
78.
De Lorenzi D Mandara MT Tranquillo M Baroni M Gasparinetti N Gandini G Masserdotti C Bonfanti U Bertolini G Vian P Bernardini M 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2006,35(2):208-214
BACKGROUND: The increased sophistication of imaging techniques in veterinary medicine allows the detection of a wide variety of intracranial and intraspinal lesions; however, imaging often does not provide a definitive diagnosis for nervous system (NS) lesions. Cytology is emerging as a useful diagnostic tool for obtaining a fast and accurate assessment of NS lesions, but little information is available for dogs and cats. OBJECTIVES: The purpose of this study was to assess the accuracy of cytologic evaluation of squash samples from NS lesions in dogs and cats and to consider cytology-based diagnostic guidelines and sources of misdiagnosis. METHODS: Cytologic specimens from masses localized in the central and peripheral NS taken during surgery or postmortem examination were classified into 3 groups according to the final histopathologic diagnosis: Group 1 = completely correct diagnosis, when the cytologic diagnosis and final histologic diagnosis were exactly correlated; Group 2 = partial correlation, when the cytologic diagnosis only partially correlated with the final histologic diagnosis, and Group 3 = no correlation, when the cytologic diagnosis was incorrect and there was no correlation with the general histologic type of lesion. The diagnostic accuracy of cytopathology was calculated by considering the histopathologic diagnosis as the "gold standard," and calculating a 95% confidence interval (CI). RESULTS: A total of 42 animals (33 dogs and 9 cats) were included in the study. The cytologic diagnoses were classified in Group 1 for 32 cases (76%; 95% CI 0.63-0.89), in Group 2 for 6 cases (14%; 95% CI 0.04-0.25), and in Group 3 for 4 cases (10%; 95% CI 0.006-0.18). Considering both complete and partial correlation as an adequate result, cytologic diagnosis was satisfactory in 90% of biopsies. CONCLUSIONS: Although the current series of cases is relatively small, cytologic evaluation of squash preparations can be considered a fairly accurate and reliable tool in the diagnosis of NS lesions. 相似文献
79.
Origanum vulgare subsp. hirtum (Link) Ietswaart (Greek oregano) has been cultivated since ancient times thanks to its herbal and therapeutic properties. Currently, it is added in various commercial preparations thanks to its essential oil composition. This group of secondary compounds is affected in quantity and quality by biotic and abiotic factors during the cultivating phase and by the postharvest management. Thus, the aims of the work were to study: (1) how the growing conditions (soil full-light treatment; pot full-light treatment; pot 50%-shade treatment) can affect the essential oil content and the essential oil profile of Greek oregano branches at full-blossoming stage; and (2) how the postharvest management (distillation of the essential oil from fresh herbs, dehumidified herbs or oven-dried herbs) can affect the essential oil content and the essential oil profile of this species. The growing conditions significantly affected the biometrical parameters. The pot full-light treatment contained the highest dry matter percentage (36.5%) and the highest essential oil content, which was directly correlated to the former parameter (r = 0.890**). The postharvest management did not affect the essential oil content. The growing condition significantly affected the characterizing γ-terpinene, cis-sabinene hydrate, 4-terpineol, α-terpinene, linalyl acetate, and β-bisabolene, while it did not affect carvacrol (mean value 15.8%), p-cymene (mean value 6.0%), or sabinene (mean value 3.9%). The postharvest management significantly affected carvacrol, cis-sabinene hydrate, 4-terpineol, p-cymene, α-terpinene, linalyl acetate, and β-bisabolene, while it did not affect γ-terpinene (mean value 14.7%). The response of some compounds to growing conditions led us to hypothesise an essential oil profile of the plants grown in pots at 50%-shade to be more of a vegetative stage type oil than the essential oil profile of the plants grown in soil, although all were at the blossoming stage. The analyses on the individual compounds indicated that, even though the essential oil content in oregano did not change with a change in postharvest management, biochemical changes occurred on the profile. These could be due to enzyme activity, dilution effect or temperature effect during the drying processes. The oven-drying process and the dehumidifying process changed the essential oil profile in a similar way compared to the essential oil profile distilled from fresh herbs. Thus, when it is not possible to extract the essential oil directly from fresh herbs, processors can dry the oregano according to the equipments they have available. 相似文献
80.
Nicola Dal Ferro Elisa Cocco Antonio Berti Barbara Lazzaro Francesco Morari 《Archives of Agronomy and Soil Science》2018,64(11):1518-1533
The cost-effectiveness of adopting agri-environmental measures (AEMs) in Europe, which combine agricultural productions with reduced N losses, is debated due to poorly targeted site-specific funding that is allocated regardless of local variability. An integrated DAYCENT model-GIS platform was developed combining pedo-climatic and agricultural systems information. The aim was to evaluate best strategies to improve N fluxes of agro-ecosystems within a perspective of sustainable intensification. Indicators of agronomic efficiency and environmental quality were considered. The results showed that agronomic benefits were observed with a continuous soil cover (conservation agriculture and cover crops), which enhanced nitrogen use efficiency (+17%) and crop yields (+34%), although in some cases these might be overestimated due to modelling limitations. An overall environmental improvement was found with continuous soil cover and long-term change from mineral to organic inputs (NLeach < 10 kg ha?1 a?1, N-N2O emissions < 1 kg ha?1 a?1, soil C stock > 45 Mg ha?1), which were effective in the sandy soils of western and eastern Veneto with low SOM, improving the soil-water balance and nutrients availability over time. Results suggest that AEM subsidies should be allocated at a site-specific level that includes pedo-climatic variability, following a result-oriented approach. 相似文献