全文获取类型
收费全文 | 763篇 |
免费 | 42篇 |
国内免费 | 1篇 |
专业分类
林业 | 27篇 |
农学 | 11篇 |
基础科学 | 13篇 |
87篇 | |
综合类 | 121篇 |
农作物 | 20篇 |
水产渔业 | 30篇 |
畜牧兽医 | 464篇 |
园艺 | 9篇 |
植物保护 | 24篇 |
出版年
2023年 | 6篇 |
2021年 | 11篇 |
2020年 | 18篇 |
2019年 | 17篇 |
2018年 | 11篇 |
2017年 | 21篇 |
2016年 | 17篇 |
2015年 | 15篇 |
2014年 | 16篇 |
2013年 | 29篇 |
2012年 | 27篇 |
2011年 | 28篇 |
2010年 | 15篇 |
2009年 | 20篇 |
2008年 | 30篇 |
2007年 | 26篇 |
2006年 | 27篇 |
2005年 | 25篇 |
2004年 | 27篇 |
2003年 | 20篇 |
2002年 | 28篇 |
2001年 | 22篇 |
2000年 | 18篇 |
1999年 | 22篇 |
1998年 | 13篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 10篇 |
1991年 | 13篇 |
1990年 | 11篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 14篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 10篇 |
1983年 | 10篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1974年 | 12篇 |
1973年 | 10篇 |
1972年 | 5篇 |
1970年 | 6篇 |
1966年 | 8篇 |
1941年 | 6篇 |
1940年 | 7篇 |
1927年 | 5篇 |
排序方式: 共有806条查询结果,搜索用时 31 毫秒
801.
Polly M Taylor MA VetMB PhD DVA MRCVS Stelio PL Luna DVM PhD Kate L White MA Vet MB CertVA MRCVS Malcolm Bloomfield Abigail L Fowden MA PhD 《Veterinary anaesthesia and analgesia》2001,28(3):119-125
Objective To characterize intravenous anaesthesia with detomidine, ketamine and guaiphenesin in pregnant ponies. Animals Twelve pony mares, at 260–320 days gestation undergoing abdominal surgery to implant fetal and maternal vascular catheters. Materials and methods Pre‐anaesthetic medication with intravenous (IV) acepromazine (30 µg kg?1), butorphanol (20 µg kg?1) and detomidine (10 µg kg?1) preceded induction of anaesthesia with detomidine (10 µg kg?1) and ketamine (2 mg kg?1) IV Maternal arterial blood pressure was measured directly throughout anaesthesia and arterial blood samples were taken at 20‐minute intervals for measurement of blood gases and plasma concentrations of cortisol, glucose and lactate. Anaesthesia was maintained with an IV infusion of detomidine (0.04 mg mL?1), ketamine (4 mg mL?1) and guaiphenesin (100 mg mL?1) (DKG) for 140 minutes. Oxygen was supplied by intermittent positive pressure ventilation (IPPV) adjusted to maintain PaCO2 between 5.0 and 6.0 kPa (38 and 45 mm Hg), while PaO2 was kept close to 20.0 kPa (150 mm Hg) by adding nitrous oxide. Simultaneous fetal and maternal blood samples were withdrawn at 90 minutes. Recovery quality was assessed. Results DKG was infused at 0.67 ± 0.17 mL kg?1 hour?1 for 1 hour then reduced, reaching 0.28 ± 0.14 mL kg?1 hour?1 at 140 minutes. Arterial blood gas values and pH remained within intended limits. During anaesthesia there was no change in heart rate, but arterial blood pressure decreased by 10%. Plasma glucose and lactate increased (10‐fold and 2‐fold, respectively) and cortisol decreased by 50% during anaesthesia. Fetal umbilical venous pH, PO2 and PCO2 were 7.34 ± 0.06, 5.8 ± 0.9 kPa (44 ± 7 mm Hg) and 6.7 ± 0.8 kPa (50 ± 6 mm Hg); and fetal arterial pH, PO2 and PCO2 were 7.29 ± 0.06, 4.0 ± 0.7 kPa (30 ± 5 mm Hg) and 7.8 ± 1.7 kPa (59 ± 13 mm Hg), respectively. Surgical conditions were good but four ponies required a single additional dose of ketamine. Ponies took 60 ± 28 minutes to stand and recovery was good. Conclusions and clinical relevance Anaesthesia produced with DKG was smooth while cardiovascular function in mare and fetus was well preserved. This indicates that DKG infusion is suitable for maintenance of anaesthesia in pregnant equidae. 相似文献
802.
Food processing conditions may affect the extractability and molecular weight of β‐glucans and arabinoxylans in cereal products. This can dramatically affect the functional and physiological properties of the final products. Therefore, the purpose of this research was to explore the effects of jet cooking on the content, extractability, and molecular weights of these polymers in barley flour from a high β‐glucan, waxy barley genotype, Prowashonupana. Barley flours were jet cooked without pH adjustment or after adjusting to pH 7, 9, or 11. Jet cooking without pH adjustment increased the extractability of β‐glucans from 15.4 to 38.0% when extracted with water at 30°C. As pH during jet cooking increased, the extractability further increased to 63.5% at pH 11. Arabinoxylan extractability was only substantially affected when the pH of jet cooking was alkaline (extractability increased from 11.4 to 48.5% when jet cooked at pH 11). Jet cooking without pH adjustment resulted in slight increases in peak molecular weights for both polymers (β‐glucan increased from 420,000 to 443,000; arabinoxylan increased from 119,000 to 125,000); higher pH values during jet cooking resulted in minor decrease in molecular weights. 相似文献
803.
Muir JG Shepherd SJ Rosella O Rose R Barrett JS Gibson PR 《Journal of agricultural and food chemistry》2007,55(16):6619-6627
Fructans are not digested in the small intestines of humans. While many health benefits have been attributed to these carbohydrates, they can cause gastrointestinal symptoms in some individuals. We measured the total fructans in 60 vegetables and 43 fruits using the Megazyme fructan assay. Vegetables with the highest quantity of fructans included garlic, artichoke, shallots, leek bulb, and onions (range, 1.2-17.4 g/100 g fw). Fruits with low, but detectable, fructans included longon, white peach, persimmon, and melon (range, 0.21-0.46 g/100 g fw). The fructan assay was modified to provide an estimate of the average chain length (degree of polymerization) for high fructan vegetables. d-Fructose can also be malabsorbed in the small intestine of humans, so the d-fructose content in some foods was measured to supplement the current food tables. Research in this area will be facilitated through the availability of more comprehensive food composition data. 相似文献
804.
Fablet C Dorenlor V Eono F Eveno E Jolly JP Portier F Bidan F Madec F Rose N 《Preventive veterinary medicine》2012,104(3-4):271-280
A cross-sectional study involving 143 farrow-to-finish herds was carried out to identify herd-level noninfectious factors associated with pneumonia and pleuritis in slaughter pigs. Data related to herd characteristics, biosecurity, management and housing conditions were collected by questionnaire during a farm visit. Climatic conditions were measured over 20 h in the post-weaning and finishing rooms where the slaughter pigs were kept. After these on-farm investigations, the finishing pigs were examined at slaughter for lung lesions. A sample of 30 randomly selected pigs per herd was scored for pneumonia and pleuritis. Herds were grouped into three categories according to their pneumonia median score (class 1: ≤ 0.5; class 2: 0.53.75). For pleuritis, a herd was deemed affected if at least one pig had a high pleuritis score (≥ 3). A multinomial logistic regression model was used to identify factors associated with pneumonia classes 2 and 3. A logistic regression for binary outcome was used to identify risk factors for severe pleuritis. An interval of less than four weeks between successive batches (OR=4.5, 95% confidence interval (95% CI): 1.5-13.6, p<0.01), large finishing room size (OR=4.3, 95% CI: 1.6-11.6, p<0.01) and high mean CO(2) concentration in the finishing room (OR=4.2, 95%CI: 1.6-11.3, p<0.01), significantly increased the odds for a herd to be in class 2 for pneumonia. The same risk factors were found for class 3 and, in addition, a direct fresh air inlet from outside or from the corridor in the post-weaning room vs an appropriate ceiling above the pigs (OR=5.1, 95% CI: 1.4-18.8, p=0.01). The risk for a herd to have at least one pig with a high pleuritis score was increased when the farrowing facilities were not disinsected (OR=2.7, 95% CI: 1.2-5.8, p=0.01), when tail docking was performed later than 1.5 days after birth (OR=2.6, 95% CI: 1.2-5.7, p=0.01) and if the piglets were castrated when more than 14 days old (OR=2.7, 95%CI: 1.1-6.8, p=0.03). A temperature range of less than 5°C for the ventilation control rate in the farrowing room (OR=2.7, 95% CI: 1.2-5.9, p=0.01), a mean temperature in the finishing room below 23°C (OR=3.0, 95% CI: 1.3-6.8, p<0.01) and large herd size (OR=3.1, 95% CI: 1.4-6.9, p<0.01) were also associated with increased risk of pleuritis. The factors affecting pneumonia and pleuritis seemed to be different. All rearing steps from farrowing to finishing must be taken into account in any health programme aimed at controlling pneumonia and pleuritis and lung health may be improved through several pathways, i.e. correcting managerial and hygienic factors, implementing an appropriate and well-functioning ventilation in order to offer favorable climatic conditions. 相似文献
805.
Rioja Rose Angeli Palomar-Abesamis Nadia Juinio-Meñez Marie Antonette 《Aquaculture International》2022,30(2):1087-1088
Aquaculture International - 相似文献
806.
da Silva Reginaldo Barboza Iori Piero Tavares Rose Luiza Moraes de Souza Zigomar Menezes de Lima Camila Cassante de Melo Silva Francisca Alcivânia de Souza Bento Marília 《Precision Agriculture》2022,23(3):984-1007
Precision Agriculture - Changes in land use in riverside ecosystems added to the flood and ebb regimes of rivers modify the spatial variability of the physical–mechanical attributes of soil,... 相似文献