全文获取类型
收费全文 | 696篇 |
免费 | 45篇 |
专业分类
林业 | 22篇 |
农学 | 5篇 |
基础科学 | 2篇 |
34篇 | |
综合类 | 171篇 |
农作物 | 18篇 |
水产渔业 | 20篇 |
畜牧兽医 | 416篇 |
园艺 | 8篇 |
植物保护 | 45篇 |
出版年
2021年 | 8篇 |
2019年 | 9篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 42篇 |
2012年 | 21篇 |
2011年 | 33篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 40篇 |
2007年 | 23篇 |
2006年 | 21篇 |
2005年 | 21篇 |
2004年 | 29篇 |
2003年 | 22篇 |
2002年 | 14篇 |
2001年 | 21篇 |
2000年 | 25篇 |
1999年 | 14篇 |
1998年 | 16篇 |
1997年 | 8篇 |
1996年 | 11篇 |
1995年 | 6篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 16篇 |
1990年 | 19篇 |
1989年 | 9篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1976年 | 7篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1937年 | 4篇 |
1936年 | 5篇 |
1935年 | 6篇 |
1919年 | 9篇 |
1916年 | 4篇 |
1914年 | 5篇 |
1913年 | 4篇 |
排序方式: 共有741条查询结果,搜索用时 31 毫秒
1.
Karol A. Mathews DVM DVSc Melanie J. Brooks RVT Anne E. Valliant BSC 《Journal of Veterinary Emergency and Critical Care》1996,6(1):33-43
A one year prospective study was conducted to determine the association between intravenous catheter contamination and increased dwell time, and to identify any related risk factors. Intravenous catheters obtained from 23 cats and 98 dogs in the Intensive Care Unit at the Ontario Veterinary College with dwell times > 72 hours for the test group (n=58) and < 72 hours for a corresponding control group (n=63) were cultured between April 1991 and March 1992. One hundred and twenty one catheters were cultured, 16 jugular, 99 cephalic, and 6 saphenous. The overall contamination rate was 13 out of 121 catheters cultured (10.7%); 9/63 (14.3%) control and 4/58 (6.9%) test catheters. The bacteria isolated were E.aerogenes, S.aureus (3), P.aeruginosa, P.multocida, and Bacillus sp (7). The Bacillus sp positive catheters (5 control and 2 test) were placed during a five day period, and contaminated gauze squares were identified as the source of infection in these catheters. After these were removed from the study, the group infection rate was 6.9% control and 3.6% test. There was no significant difference between groups and no associated risk factors were identified. We conclude that intravenous dwell time need not be restricted to <72 hours. 相似文献
2.
Michael S. Stone Ian B. Johnstone Marjory Brooks Trent K. Bollinger Susan M. Cotter 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1994,8(1):57-61
A circulating anticoagulant was detected in a 2-year-old Chesapeake Bay Retriever with hemolytic anemia, nephrotic syndrome, thrombocytopenia, polyarthropathy, and pulmonary thromboembolism. A persistent prolongation of the activated partial thromboplastin time (aPTT) was detected, and it did not correct with repeated administration of fresh frozen plasma. The aPTT was still prolonged, with a 1:1 mixture of patient's plasma and normal dog plasma in vitro, suggesting the presence of a circulating inhibitor. Results of assays to characterize the inhibitor were compatible with those described for the lupus anticoagulant in human patients with systemic lupus erythematosus. Paradoxically, patients having the lupus anticoagulant are at increased risk for thrombosis. Pulmonary thromboembolism has been described as a frequent complication of immune-mediated hemolytic anemia in the dog, and the presence of a circulating anticoagulant should be considered as a potential mechanism. 相似文献
3.
D E Brooks D A Samuelson K N Gelatt P J Smith 《American journal of veterinary research》1989,50(6):908-914
Scanning electron microscopy of vascular corrosion casts of the optic nerve region in normal and glaucomatous Beagles demonstrated that the blood supply to the laminar optic nerve is derived from short posterior ciliary arteries, cilioretinal arteries, and longitudinal pial vessels. The short posterior ciliary arteries formed a ring of striated pillars around the scleral canal. The central retinal artery was not present in the dog. Differences between the casts in normal and glaucomatous dogs were not detected. 相似文献
4.
5.
Dimski DS Brooks CL Johnson SE 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》1990,19(2):40-44
Type III procollagen peptide (P-3-P) is a serum marker for hepatic fibrosis in humans. The utility of a commercially available radioimmunoassay for P-3-P was evaluated in the dog. The specificity of the assay was assessed by polyacrylamide gel electrophoresis (PAGE) of canine serum and purified bovine P-3-P, followed by Western immunoblotting with rabbit aniti-P-3-P serum. The sensitivity was assessed by performing the radioimmunoassay on dilutions of sera from 22 dogs. Polyacrylamide gel electrophoresis of purified bovine P-3-P and sera from two dogs suspected of having elevated P-3-P concentrations revealed no homologous bands of staining. Western immunoblotting showed marked cross-reactivity of the high antisera concentrations with several components of the serum proteins, but none corresponding to the purified P-3-P. All tested sera from dogs had minimal competitive binding with radiolabeled P-3-P in the radioimmunoassay. Dilution curves of dog sera did not parallel either the standard curve or the dilution curve of a known test human serum. There were no statistically different P-3-P concentrations in any of the groups of dogs studied. It was concluded that currently available radioimmunoassay kits for the measurement of P-3-P in the human are not applicable in the dog. Seemingly, the structure or metabolism of canine P-3-P may vary significantly from that of the bovine or human, limiting the sensitivity and specificity of this assay in the dog. 相似文献
6.
7.
8.
Organic zinc and copper supplementation on antioxidant protective mechanism and their correlation with sperm functional characteristics in goats
下载免费PDF全文
![点击此处可从《Reproduction in domestic animals》网站下载免费的PDF全文](/ch/ext_images/free.gif)
M Narasimhaiah A Arunachalam S Sellappan VK Mayasula PR Guvvala SK Ghosh V Chandra J Ghosh H Kumar 《Reproduction in domestic animals》2018,53(3):644-654
Trace minerals feeding had significant effects on sperm production and fertility with better absorption and proper utilization within the body for optimum reproductive function. Several studies have shown that more influenced trace elements in the diets of animals are copper (Cu) and zinc (Zn). Bucks showing deficiency of this mineral might affect the quality of semen production which in turn would affect the fertility. This experiment was thus designed to test the effects of organic Cu and Zn supplementation on antioxidants enzyme activities and sperm functional attributes in fresh semen of bucks. Forty bucks (n = 40, Aged 5 months) were assigned to ten groups of four animals in each group, supplemented (for a period of 8 months) with different levels of organic Zn: 20 mg (T2), 40 mg (T3) and 60 mg (T4), organic Cu: 12.5 mg (T5), 25 mg (T6), 37.5 mg (T7) and combined organic Zn and Cu: 20 + 12.5 mg (T8), 40 + 25 mg (T9), 60 + 37.5 mg (T10), respectively, per kg dry matter and no additional mineral diet (control; T1). One hundred and sixty semen samples were collected through electro‐ejaculator and analysed for sperm quantity, quality, acrosome intactness and plasma membrane integrity and correlated with the catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase enzyme activities in seminal plasma. The results indicated organic Cu and zinc supplemented bucks produced more sperm cells, had higher sperm concentrations, maintained higher (p < .01) sperm livability, plasma membrane and acrosome integrities, more motility and velocity. The increased antioxidant enzyme activities, reduced oxidative stress and lowered lipid peroxidation were positively correlated (p < .05) with the sperm functional attributes. In conclusion, organic Cu and Zn supplement to male goats showed protective roles against oxidative damage and maintained better fresh semen characteristics. 相似文献
9.