全文获取类型
收费全文 | 220569篇 |
免费 | 11853篇 |
国内免费 | 149篇 |
专业分类
林业 | 9284篇 |
农学 | 7289篇 |
基础科学 | 1387篇 |
28538篇 | |
综合类 | 34961篇 |
农作物 | 8641篇 |
水产渔业 | 11300篇 |
畜牧兽医 | 113434篇 |
园艺 | 3045篇 |
植物保护 | 14692篇 |
出版年
2020年 | 1874篇 |
2019年 | 2247篇 |
2018年 | 3264篇 |
2017年 | 3708篇 |
2016年 | 3403篇 |
2015年 | 2945篇 |
2014年 | 3687篇 |
2013年 | 8948篇 |
2012年 | 6622篇 |
2011年 | 8140篇 |
2010年 | 5404篇 |
2009年 | 5458篇 |
2008年 | 8006篇 |
2007年 | 7666篇 |
2006年 | 7174篇 |
2005年 | 6617篇 |
2004年 | 6342篇 |
2003年 | 6494篇 |
2002年 | 5958篇 |
2001年 | 7005篇 |
2000年 | 6973篇 |
1999年 | 5646篇 |
1998年 | 2388篇 |
1997年 | 2323篇 |
1996年 | 2163篇 |
1995年 | 2586篇 |
1994年 | 2241篇 |
1993年 | 2167篇 |
1992年 | 4363篇 |
1991年 | 4603篇 |
1990年 | 4550篇 |
1989年 | 4556篇 |
1988年 | 4166篇 |
1987年 | 4144篇 |
1986年 | 4195篇 |
1985年 | 3995篇 |
1984年 | 3250篇 |
1983年 | 2904篇 |
1982年 | 1986篇 |
1979年 | 2926篇 |
1978年 | 2340篇 |
1977年 | 1974篇 |
1976年 | 1983篇 |
1975年 | 2096篇 |
1974年 | 2487篇 |
1973年 | 2559篇 |
1972年 | 2441篇 |
1971年 | 2191篇 |
1970年 | 2222篇 |
1969年 | 2135篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
A. J. van den Brom-Spierenburg M. J. P. Theelen M. M. Sloet van Oldruitenborgh-Oosterbaan 《Equine Veterinary Education》2019,31(4):191-194
Dermatographism is a common condition in man that occurs when pressure is applied to the skin and mast cells are triggered to release histamine, causing local urticarial lesions. This case report concerns a 4-year-old Quarter Horse gelding that was presented with pressure induced urticaria. Moderate pressure on the skin induced nonpruritic urticaria-like swelling after approximately 3–5 min, which lasted for approximately 2–3 h. Initial treatment with cyproheptadine gave an incomplete response and unacceptable sedation as a side effect. On the second generation antihistamine cetirizine (0.2 mg/kg bwt twice daily), dermatographism was no longer present and no side effects occurred. Treatment was continued for 4 months, with at least three attempts to discontinue therapy resulting in recurrence of lesions within 24 h. Lesions resolved each time within 24 h of recommencing therapy. Dermatographism did not recur after the horse was moved to another location despite discontinuation of therapy. This report describes a case of equine dermatographism responsive to cetirizine. 相似文献
992.
993.
E. A. Walmsley M. Jackson L. Wells-Smith R. C. Whitton 《Equine veterinary journal》2019,51(6):720-726
994.
995.
Jervis M. Huaman O. Cahuascanco B. Bahamonde J. Cortez J. Arias J. I. Torres C. G. Peralta O. A. 《Veterinary research communications》2019,43(3):165-178
Veterinary Research Communications - Mesenchymal stem cells (MSCs) are found in virtually all tissues, where they self-renew and differentiate into multiple cell types. Cumulative data indicate... 相似文献
996.
O. A. Sh. Abdurahman 《Veterinary research communications》1996,20(1):9-14
Milk samples (n=160) from 7 clinically healthy bactrian camels were cultured to detect subclinical udder infection. The samples were assessed by the Californian mastitis test (CMT) and somatic cell count (SCC). Bacteria were recovered from 36 (22.5%) of the milk samples. Staphylococcus aureus and coagulase-negative staphylococci (CNS) were the main organisms found.Infected quarters had significantly higher mean values for the SCC (p<0.01) and CMT (p<0.001) than non-infected quarters. All 7 camels were infected with CNS but only 4 with S. aureus. CMT values for S. aureus-infected camels were significantly higher than for those only infected with CNS. The values for SCC and CMT were significantly influenced by the stage of lactation (p<0.05). No significant difference was found from the effect of the quarters. Both SCC and CMT were of value in predicting the infection status of the udder.Abbreviations CMT
California mastitis test
- SCC
somatic cell count
- CNS
coagulase-negative staphylococci 相似文献
997.
This study presents the estimates of heritability for spondylosis deformans in the boxer based on 353 offspring from 24 randomly selected sires, each with at least three radiographically investigated offspring. The estimated heritability (h2) for maximum degree of osteophyte development was high, both when estimated by paternal half-sib correlation (0·42) and by the regression of offspring based on the parents (0·62). The heritability for the number of affected discs estimated by paternal half-sib correlation was also high (0·47). The estimate of heritability for the number of affected discs based on regression of offspring on the parents was lower at 0·13. All heritabilities had large standard errors. A positive phenotypic correlation between spondylosis deformans and hip dysplasia was observed. Assuming a significant portion of the correlation is genetic, this fact may permit selection against spondylosis deformans without negatively influencing the incidence of hip dysplasia. Since the incidence of spondylosis deformans is high even in young dogs, it should be possible to detect a large proportion of genetically predisposed animals by radiographic examination of the spine at one year of age; at the same time that dogs are presented for a routine test for hip dysplasia. 相似文献
998.
Antipyrine disposition in the dehydrated camel 总被引:1,自引:0,他引:1
Z. BEN-ZVI M. RUBIN C. VAN CREVELD R. YAGIL 《Journal of veterinary pharmacology and therapeutics》1995,18(2):137-140
In the present study the effects of water deprivation in the camel ( Camelus dromedarius ) on the pharmacokinetic profile of antipyrine were assessed. A crossover design was used. The pharmacokinetics of antipyrine in adult and young camels were compared. Antipyrine was administered intravenously to young and adult female camels when water was available ad libitum and to the adult camels after 14 days of dehydration. The elimination half-life of antipyrine in watered adult camels was 136.5 ± 16.7 min. The half-life of elimination and the mean residence time of antipyrine were significantly prolonged following dehydration. The observed effects of water deprivation were not a function of age, as the pharmacokinetic profile of antipyrine in young camels was similar to that of the adults, but more likely due to the changes in oxidative metabolic capacity of the liver as a result of a reduced general metabolism. The results of the present study also show that the intrinsic clearance of antipyrine is proportional to the camel's body weight, as previously shown for other mammalian species. 相似文献
999.
Pharmacokinetics and bioequivalence of parenterally administered doramectin in cattle 总被引:2,自引:1,他引:2
M.A. NOWAKOWSKI M.J. LYNCH D.G. SMITH N.B. LOGAN† D.E. MOUZIN† J. LUKASZEWICZ N.I. RYAN R.P. HUNTER R.M. JONES 《Journal of veterinary pharmacology and therapeutics》1995,18(4):290-298
Plasma concentrations of doramectin in 40 cattle dosed by subcutaneous (sc) or intramuscular (i.m.) injection (200 μg/kg) were compared to assess the bioequivalence of the two routes of administration. Peak concentration ( C max ), and areas under the concentration curve ( AUC0– ) were determined from plasma concentrations. Animals treated by the sc route showed a mean AUC0– of 457 ± 66 ng±day/mL (± SD) and a mean C max of 27.8 ± 7.9 ng/mL. Results from the i.m. treatment group showed a mean AUC 0– of 475 ± 82 ng-day/mL and a mean C max of 33.1 ± 9.0 ng/mL Absorption constants ( k a ) determined by modelling were 0.542 ± 0.336 day-1 after sc administration and 0.710 ± 0.357 day-1 after i.m. administration. The 90% confidence limits on the difference between mean AUC 0– values for the sc and i.m. groups fell within 20% of the mean value for the subcutaneous group. C max was somewhat greater for the i.m. route. The 90% confidence limits on the difference in mean In ( T max +1) also fell within 20% of the mean sc value. Based on this analysis, bioequivalence of the sc and i.m. formulation has been established. 相似文献
1000.
REBECCA L. FRANKENY VMD DAVID A. WILSON DVM MS Diplomate ACVS NAT T. MESSER IV DVM Diplomate ABVP CYNTHIA CAMPBELL-BEGGS DVM 《Veterinary surgery : VS》1995,24(6):515-517
Jejunojejunal intussusception occurred after jejunal resection and stapled functional end-to-end anastomosis in two pony mares. In both mares, the lead point of the intussusception was the stapled functional end-to-end (FEE) anastomosis. The stapled free ends of jejunum were oversewn with an inverting suture pattern. A possible explanation for development of the intussusception was the acute angle created in the intestine by the FEE anastomsis. This angulation may have impaired flow of ingesta causing motility changes that predisposed the site to intussusception. Because the oversewn blind intestinal ends acted as the lead point for formation of the intussusception, it may be inadvisable to oversew the stapled anastomotic ends. 相似文献