全文获取类型
| 收费全文 | 9095篇 |
| 免费 | 776篇 |
专业分类
| 林业 | 148篇 |
| 农学 | 422篇 |
| 基础科学 | 32篇 |
| 1364篇 | |
| 农作物 | 79篇 |
| 水产渔业 | 2579篇 |
| 畜牧兽医 | 4007篇 |
| 植物保护 | 1240篇 |
出版年
| 2022年 | 2篇 |
| 2021年 | 156篇 |
| 2020年 | 556篇 |
| 2019年 | 1142篇 |
| 2018年 | 888篇 |
| 2017年 | 935篇 |
| 2016年 | 936篇 |
| 2015年 | 813篇 |
| 2014年 | 796篇 |
| 2013年 | 957篇 |
| 2012年 | 445篇 |
| 2011年 | 457篇 |
| 2010年 | 583篇 |
| 2009年 | 241篇 |
| 2008年 | 221篇 |
| 2007年 | 62篇 |
| 2006年 | 91篇 |
| 2005年 | 82篇 |
| 2004年 | 84篇 |
| 2003年 | 81篇 |
| 2002年 | 98篇 |
| 2001年 | 66篇 |
| 2000年 | 98篇 |
| 1999年 | 6篇 |
| 1997年 | 11篇 |
| 1996年 | 4篇 |
| 1995年 | 4篇 |
| 1994年 | 5篇 |
| 1993年 | 6篇 |
| 1991年 | 1篇 |
| 1990年 | 4篇 |
| 1989年 | 2篇 |
| 1986年 | 2篇 |
| 1985年 | 1篇 |
| 1984年 | 1篇 |
| 1983年 | 2篇 |
| 1982年 | 3篇 |
| 1981年 | 1篇 |
| 1980年 | 1篇 |
| 1979年 | 1篇 |
| 1978年 | 6篇 |
| 1977年 | 5篇 |
| 1976年 | 1篇 |
| 1975年 | 3篇 |
| 1974年 | 2篇 |
| 1973年 | 1篇 |
| 1970年 | 4篇 |
| 1968年 | 1篇 |
| 1966年 | 1篇 |
| 1963年 | 1篇 |
排序方式： 共有9871条查询结果，搜索用时 30 毫秒
991.
I. François F.‐X. Lalèyê M. Micat K. Benredouane K. Portier 《Equine veterinary journal》2014,46(5):596-600
992.
E. Salesov F.S. Boretti N.S. Sieber‐Ruckstuhl K.M. Rentsch B. Riond R. Hofmann‐Lehmann P.R. Kircher E. Grouzmann C.E. Reusch 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2015,29(2):597-602
Background
Diagnosis of pheochromocytoma (PC) is based on a combination of clinical suspicion, finding an adrenal mass, increased plasma, and urine concentrations of catecholamine metabolites and is finally confirmed with histopathology. In human medicine, it is controversial whether biochemically testing plasma is superior to testing urine.Objectives
To measure urinary and plasma catecholamines and metanephrines in healthy dogs, dogs with PC, hypercortisolism (HC), and nonadrenal diseases (NAD) and to determine the test with the best diagnostic performance for dogs with PC.Animals
Seven PC dogs, 10 dogs with HC, 14 dogs with NAD, 10 healthy dogs.Methods
Prospective diagnostic clinical study. Urine and heparin plasma samples were collected and stored at −80°C before analysis using high‐pressure liquid chromatography (HPLC) coupled to electrochemical detection or tandem mass spectrometry were performed. Urinary variables were expressed as ratios to urinary creatinine concentration.Results
Dogs with PC had significantly higher urinary normetanephrine and metanephrine : creatinine ratios and significantly higher plasma‐total and free normetanephrine and plasma‐free metanephrine concentrations compared to the 3 other groups. There were no overlapping results of urinary normetanephrine concentrations between PC and all other groups, and only one PC dog with a plasma normetanephrine concentration in the range of the dogs with HC and NAD disease. Performances of total and free plasma variables were similar. Overlap of epinephrine and norepinephrine results between the groups was large with both urine and plasma.Conclusion and clinical importance
Measurement of normetanephrine is the preferred biochemical test for PC and urine was superior to plasma. 相似文献993.
J. Deng X. Wu S. Bin T.‐J. Li R. Huang Z. Liu Y. Liu Z. Ruan Z. Deng Y. Hou Y.‐L. Yin 《Journal of animal physiology and animal nutrition》2010,94(2):220-226
Experiments were conducted to determine the effects of feeding different starch sources on piglets. Four diets were formulated with maize, brown rice, sticky rice and Hi‐Maize 1043 as starch sources, with resistant starch (RS) contents of 2.3%, 0.9%, 0.0%, 20.6%, and amylose and amylopectin ratio of 0.23%, 0.21%, 0.18%, 0.06% respectively. Fifty‐six pigs weaned at 28 days of age were randomly assigned to one of the four diets. In Exp. 1, six piglets in each group were fitted with an indwelling jugular catheter. After 25 days of feeding trial, venous blood samples were obtained at time zero and every 1 h for 4 h. In Exp. 2, the remaining piglets were used to determine the effects of different starch sources on the fractional synthesis rate (FSR). The results indicated that feeding the Hi‐Maize 1043 diet decreased (p < 0.05) plasma contents of glucose, insulin, lactic acid and T3, while sticky rice increased plasma contents of glucose and insulin. The insulin contents in piglets fed the sticky rice diet was 69.2 μIU/ml at 1 h post‐feeding which was highest among the starch diets. The FSR in the pancreas, spleen, duodenum, jejunum, ileum and colon in the corn group were much higher (p < 0.05) than that in the sticky rice group. These results suggest that RS is potentially beneficial for improving insulin sensitivity in young pigs and that the ratio of amylose and amylopectin have significantly effects on the FSR in splanchnic tissues in weaned piglets. Another finding of this study indicated maize with a ratio of amylose and amylopectin of 0.23 has the best starch sources for pig production. 相似文献
994.
A Ortega‐Pacheco M Jiménez‐Coello E Gutiérrez‐Blanco KY Acosta‐Viana E Guzmán‐Marín MA Zavala‐Sánchez NE Montalvo‐Beltrán MS Pérez‐Gutiérrez 《Reproduction in domestic animals》2010,45(6):1126-1129
Papaya seeds (Carica papaya Linn) have been found to have a significant effect on sperm characteristics in some mammals, including humans, but no studies have investigated the effects on dogs. In the present study, a significant decrease in sperm concentration was observed in a group of dogs treated with extracts from washed papaya seeds, but no decrease was observed in the group of dogs treated with non‐washed seeds. An important effect of extract components from washed seeds such as fatty acids is probably involved in the reduction of sperm production because of Sertoli cell damage, as has been suggested for langur monkeys. Dilution of the active components in the non‐washed papaya seeds or interference with some of the components may reduce the expected effect on spermatogenesis. This first report on the effects of a chloroformic extract of papaya seeds in dogs suggests that an increased dose is necessary to achieve azoospermia. 相似文献
995.
E. Smiet G. C. M. Grinwis J. G. B. van den Top M. M. Sloet van Oldruitenborgh‐Oosterbaan 《Equine Veterinary Education》2012,24(7):357-366
Mammary gland problems occur incidentally in horses and one of the rarer conditions is botryomycosis (bacterial pseudomycosis, bacterial granuloma, staphylococcal pseudomycetoma). This article includes a short review of equine mammary gland problems inappropriate lactation, mastitis and neoplasia and botryomycosis, and additionally 2 clinical cases of botryomycosis of the udder resulting from Staphyloccocus aureus infection will be discussed. Both cases involved nonpregnant, nonlactating mares referred for chronic mammary inflammation with draining abcessation. In both mares, botryomycosis caused by S. aureus was confirmed by histopathology and a bacterial culture. Both mares recovered fully after surgical hemimastectomy under general anaesthesia. 相似文献
996.
997.
998.
R. Sedighi‐Vesagh A. A. Naserian M. H. Ghaffari H. V. Petit 《Journal of animal physiology and animal nutrition》2015,99(4):777-787
The objective of this study was to investigate the effects of pistachio by‐products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post‐partum, 45 ± 2/kg BW) were randomly assigned to a 3 × 3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP + polyethylene glycol (PEG‐4000; 1 g/kg dry matter). Each period lasted 21 days, including 14 day for treatment adaptation and 7 day for data collection. Pistachio by‐products significantly decreased (p < 0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP + PEG and those fed the two other diets. The digestibility of NDF tended (p = 0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat‐corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p < 0.01) in FA from 8:0 to 16:0 and increases (p < 0.01) proportions of cis‐9, trans‐11 18:2 and trans‐11 18:1, monounsaturated FA, polyunsaturated FA and long‐chain FA. The saturated FA, short‐chain FA and medium‐chain FA proportions were lower (p < 0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p < 0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile. 相似文献
999.
1000.
J.‐W. Lim M.‐H. Jung S.‐J. Jung D.‐H. Kim K. H. Park S. Y. Kang 《Journal of veterinary pharmacology and therapeutics》2017,40(1):77-87
The efficacy of amoxicillin sodium for controlling field and experimental Streptococcus iniae and S. parauberis infections in olive flounder (Paralichthys olivaceus) was evaluated after a single intramuscular administration. Furthermore, the minimal inhibitory concentrations (MIC) against 21 Streptococcus strains were determined. In addition, the pharmacokinetics and residue depletion in olive flounder were investigated. Single intramuscular doses of amoxicillin sodium at 20, 40, 80, and 160 mg/kg b.w. fish significantly reduced cumulative mortality rates to 18.8–31.3% (P < 0.05) for S. iniae and to 5.0–15.0% (P < 0.01) for S. parauberis, whereas the S. iniae‐ and S. parauberis‐infected positive control groups showed cumulative mortality rates of 68.8% and 60.0%, respectively. In a S. parauberis outbreak, amoxicillin sodium reduced the cumulative mortality rate to 7.5% and 4.8% at 20 and 40 mg/kg b.w. fish, respectively, whereas that of the untreated control group was 35.2%. Peak plasma concentrations (Cmax) following a single intramuscular dose of 40 and 80 mg/kg b.w. fish were 62.64 (Tmax, 1.59 h) and 87.61 (Tmax, 3.02 h) μg/mL, respectively, with large AUC0?t/MIC and Cmax/MIC ratios, and sufficient T > MIC (time for maintaining plasma drug concentration greater than MICs) for S. iniae and S. parauberis. The estimated withdrawal period of amoxicillin sodium from muscle of olive flounder was about 8 days at 40 mg/kg b.w. fish (at 22 ± 1 °C). These results demonstrated a single intramuscular administration of amoxicillin sodium to be effective against streptococcosis in olive flounder. 相似文献