全文获取类型
收费全文 | 280篇 |
免费 | 17篇 |
国内免费 | 2篇 |
专业分类
林业 | 17篇 |
农学 | 8篇 |
基础科学 | 1篇 |
40篇 | |
综合类 | 70篇 |
农作物 | 13篇 |
水产渔业 | 19篇 |
畜牧兽医 | 113篇 |
园艺 | 5篇 |
植物保护 | 13篇 |
出版年
2023年 | 4篇 |
2022年 | 2篇 |
2021年 | 10篇 |
2020年 | 9篇 |
2019年 | 11篇 |
2018年 | 13篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 17篇 |
2012年 | 23篇 |
2011年 | 24篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 19篇 |
2007年 | 12篇 |
2006年 | 14篇 |
2005年 | 19篇 |
2004年 | 16篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 3篇 |
1995年 | 4篇 |
1993年 | 2篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1948年 | 1篇 |
1947年 | 1篇 |
1919年 | 1篇 |
1886年 | 1篇 |
1884年 | 1篇 |
1883年 | 2篇 |
排序方式: 共有299条查询结果,搜索用时 0 毫秒
91.
92.
Dlott DD 《Science (New York, N.Y.)》2005,309(5739):1333-1334
93.
Calcium oxalate urolithiasis in the canine: surgical management and preventative strategies 下载免费PDF全文
Dolinsek D 《The Canadian veterinary journal. La revue veterinaire canadienne》2004,45(7):607-609
A 4-year-old, neutered male Chihuahua was presented with inappetance, lethargy, and a tense abdomen attributed to pain. Abdominal radiographs revealed a large cystic calculus and small urethral calculi. Urethral hydropulsion followed by cystotomy were performed successfully. Dietary management was initiated as the primary means of preventing recurrence. 相似文献
94.
Dana Atwood-Harvey 《Society and Animals》2005,13(4):315-342
The medical practice of declawing has received much political debate over the past few years. Yet, empirical and theoretical research on how this practice is maintained and the ethical positions of those who actually participate in this work is lacking. Drawing from 9 months of ethnographic fieldwork in a feline-specific veterinary hospital and open-ended interviews with veterinarians and staff, this study examines veterinary staff members' attitudes toward, and strategies for, dealing with the medical practice of declawing. Specifically, findings show that a number of staff felt uncomfortable with their participation in onychectomy (declawing) and relied heavily on organizational support structures to cope both with these feelings and the moral ambiguity about the practice. Relying on these structures, the veterinarians and their staff are able simultaneously to define felines as subjects worthy of respect for their quality of life, protect their own self-identity as people who work toward the best interest of animals, and paradoxically support action toward felines that they find morally objectionable. 相似文献
95.
Stemphylium botryosum pathogenic on alfalfa (Medicago sativa) produced a phytotoxin in a defined liquid medium which caused symptoms similar in sequence and appearance to stemphylium leafspot lesion development on attached alfalfa leaflets. The molecular weight of the phytotoxin was estimated to be 19500 by gel filtration chromatography. Treatment of partially purified phytotoxin with proteinase K or subtilisin resulted in loss of phytotoxic activity. Action of the proteases in inducing loss of phytotoxicity was inhibited by phenylmethylsulphonyl fluoride. Concentrated culture filtrates were fractionated by chromatofocusing, HPLC ion-exchange and gel filtration. Gel filtration also was followed by non-denaturing electrophoresis or isoelectric focusing (IEF). Analysis of sequential fractions from each procedure by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that phytotoxic activity was consistently coincident with the presence of two major polypeptides (Mr = 26900 ± 2%; 19500 ± 4%) and a triplet of polypeptides (Mr = 15500). The constant association between the three polypeptides suggested an intermolecular interaction during fractionation. The phytotoxic activity eluted from the chromatofocusing column between pH 5·79 and 5·43 whereas IEF estimated the isoelectric point to be between 5·40 and 5·02.Immobilized concanavalin A and wheat germ lectin failed to bind phytotoxicity. Proteolytic activity in some phytotoxic gel filtration fractions was reduced by addition of phenyl-methylsulphonyl fluoride and separated from phytotoxicity by non-denaturing electrophoresis, indicating that phytotoxicity was not due to serine protease activity.Pathogenicity tests of the cool-temperature biotype on 20 plant species representing eight plant families resulted in a compatible interaction only on M. sativa and M. polymorpha. In contrast, sensitivity to the phytotoxin was observed on both pathogen-resistant and susceptible alfalfa clones along with all other plants tested with the exception of Triticum aestivum, Zea mays, Apium graveolens and Melilotus officinalis, indicating non-host-specificity of the phytotoxic polypeptides produced by the cool-temperature biotype. 相似文献
96.
97.
98.
Preston SA Trumble TN Zimmel DN Chmielewski TL Brown MP Hernandez JA 《Journal of the American Veterinary Medical Association》2008,232(1):85-90
OBJECTIVE: To characterize lameness during training and compare exercise variables and financial returns among yearling Thoroughbreds that were bought for the purpose of resale for profit. ANIMALS: 40 yearling Thoroughbreds. DESIGN: Prospective study. PROCEDURES: Horses purchased at yearling sales (summer 2004) were trained prior to resale at 2-year-olds in training sales (spring 2005). Horses were monitored daily for diagnosis and treatment of lameness during training. Selected variables, including sex, age, purchase price, lameness, distance (No. of furlongs) galloped during training, and financial returns, were compared among horses that had performance speeds (assessed at 2-year-olds in training sales) classified as fast, average, or slow. RESULTS: 37 of 40 horses became lame during training, most commonly because of joint injury. Eighteen of the lame horses had hind limb injuries only; 5 horses had injuries in forelimbs and hind limbs. The frequency of new cases of lameness increased as the date of the 2-year-olds in training sales approached. At the sales, 4, 21, and 15 horses were classified as fast, average, or slow, respectively; median financial return was slightly (but significantly) different among horses classified as fast ($14,000), average ($0), or slow (-$8,000). CONCLUSIONS AND CLINICAL RELEVANCE: Incidence of lameness during training in yearling horses purchased for the purpose of resale for profit was high. Lameness more commonly affected hind limbs than forelimbs and was attributable to joint injury in most horses. Financial returns differed between horses classified as fast and average or slow at the 2-year-olds in training sales. 相似文献
99.
Blois SL Poma R Stalker MJ Allen DG 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(8):789-792
A 2-year-old, castrated male, Australian shepherd was presented with a history of chronic mild ataxia, obesity, and lethargy. The dog was treated with levothyroxine, but the ataxia worsened. Cranial nerve abnormalities developed and the dog was euthanized. Postmortem examination revealed marked thyroid gland atrophy and widespread, severe central nervous system atherosclerosis. 相似文献
100.
Martin Kvác Bohumil Sak Dana Kvetonová Oleg Ditrich Lada Hofmannová David Modry Jirí Vítovec Lihua Xiao 《Veterinary parasitology》2008,153(3-4):363-367
Farm ruminants were infected experimentally with four mammalian gastric Cryptosporidium, namely Cryptosporidium andersoni LI03 originated from cattle and three isolates of Cryptosporidium muris from brown rat (isolate RN66), Bactrian camel (isolate CB03) and firstly characterized isolate from East African mole rat (isolate TS03). Sequence characterizations of the small-subunit rRNA gene showed that the LI03 isolate was C. andersoni and the other three isolates belonged to C. muris, although the TS03 isolate showed unique sequence variations (one single nucleotide change and four nucleotide insertions). C. andersoni LI03 was infectious for calves only, whereas lambs and kids were susceptible to C. muris CB03. C. muris TS03 and RN66 were not infectious for any farm ruminants. Infection dynamics including prepatent and patent period and infection intensity of the isolates used differed depending on the host species, but no clinical signs of cryptosporidiosis were observed in any of experimentally infected hosts. Cryptosporidium developmental stages were only detected in infected animals in the abomasum region. Histopathological changes were characterized by dilatation and epithelial metaplasia of infected gastric glands with no significant inflammatory responses in the lamina propria. 相似文献