全文获取类型
收费全文 | 484篇 |
免费 | 22篇 |
专业分类
林业 | 17篇 |
农学 | 30篇 |
基础科学 | 1篇 |
34篇 | |
综合类 | 7篇 |
农作物 | 12篇 |
水产渔业 | 15篇 |
畜牧兽医 | 360篇 |
园艺 | 5篇 |
植物保护 | 25篇 |
出版年
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 2篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 6篇 |
2016年 | 16篇 |
2015年 | 11篇 |
2014年 | 10篇 |
2013年 | 19篇 |
2012年 | 22篇 |
2011年 | 31篇 |
2010年 | 15篇 |
2009年 | 12篇 |
2008年 | 19篇 |
2007年 | 20篇 |
2006年 | 25篇 |
2005年 | 20篇 |
2004年 | 11篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 21篇 |
2000年 | 7篇 |
1999年 | 10篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 23篇 |
1991年 | 14篇 |
1990年 | 27篇 |
1989年 | 17篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 16篇 |
1985年 | 7篇 |
1983年 | 7篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有506条查询结果,搜索用时 15 毫秒
1.
M C Vickers W J Hartley R W Mason J P Dubey L Schollam 《Journal of the American Veterinary Medical Association》1992,200(11):1723-1725
Seven of 30 canaries in an aviary in New Zealand developed ophthalmic problems. Clinically, 5 birds had unilateral and 2 birds had bilateral lesions characterized by conjunctivitis, crusty exudates on eyelids, and collapse of the eyeball. Microscopic lesions in 12 of 14 eyes examined included inflammation of the choroid and retina, with osseous replacement of the globe in some. Numerous Toxoplasma gondii tachyzoites were seen in the detached retina and vitreous humor of acutely affected birds. The diagnosis of toxoplasmosis was confirmed by immunohistochemical staining with T gondii antiserum. Affected birds had encephalitis, and T gondii was localized in the brains of these by immunohistochemical examination and by use of bioassays in mice. Toxoplasmosis should be considered in differential diagnosis of ophthalmitis in canaries. 相似文献
2.
J P Dubey A N Hamir C A Hanlon C E Rupprecht 《Journal of the American Veterinary Medical Association》1992,200(4):534-536
Serum samples from 427 raccoons (93 from Pennsylvania, 45 from New Jersey, 72 from South Carolina, 68 from Virginia, 30 from Iowa, and 119 from Ohio) were evaluated for Toxoplasma gondii antibodies in dilutions of 1:25, 1:50, and 1:500. The distribution of T gondii antibody titers was less than 1:25 for 212 raccoons (49.6%), 1:25 for 34 raccoons (7.9%), 1:50 for 117 raccoons (27.4%), and greater than or equal to 1:500 for 64 raccoons (14.9%). Tissue cysts were seen in the liver, and tachyzoites were in the brain of a raccoon with abnormal neurologic signs and concurrent infection with canine distemper virus. Organisms in the liver were stained with anti-T gondii serum, and the raccoon had a T gondii titer of 1:160 in the agglutination test. 相似文献
3.
J C Silva S Ogassawara M F Marvulo J S Ferreira-Neto J P Dubey 《Journal of zoo and wildlife medicine》2001,32(3):349-351
Serum samples from 37 captive exotic felids in 12 zoos from six Brazilian states were assayed for antibodies to Toxoplasma gondii by the modified agglutination test using formalin-fixed whole tachyzoites. Titers greater than or equal to 1:20 were considered positive. Antibodies to T. gondii were found in 24 of 37 (64.9%) felids, including one European lynx (Lynx lynx), two jungle cats (Felis chaus), two servals (Leptailurus serval), two tigers (Panthera tigris), three leopards (Panthera pardus), and 14 of 27 lions (Panthera leo). This is the first serologic analysis for T. gondii infection in exotic wild felids from Brazilian zoos. 相似文献
4.
The ultrastructure of sarcocysts of macro- and microscopic species of Sarcocystis was compared from naturally infected water buffalo from India. Grossly visible sarcocysts had walls consisting of cauliflower-like villar protrusions, typical of S. fusiformis. The sarcocyst wall of the microscopic species of Sarcocystis was 6.4 microns thick and consisted of tightly packed conical villar protrusions that were 9.6 microns long and 3.7 microns wide at the base. At approximately 3 microns above the base, the distal two-thirds of the villar protrusion became conical shaped and was bent laterally at an angle of 45 degrees to the sarcocyst surface. The granular layer beneath the villar protrusions was 0.9 microns thick. In S. levinei the granular layer was 1.9 microns thick, the villar protrusions were narrow and it had a highly undulating primary cyst wall. Whether the microscopic S. levinei-like sarcocysts of Indian and Malaysian water buffalo are distinct species of Sarcocystis will require further investigation. 相似文献
5.
Reena Kamal Triveni Dutt Manjunath Patel Amitava Dey Panch Kishore Bharti Poolangulam Chinnakkan Chandran 《Tropical animal health and production》2018,50(4):701-706
In tropical countries, at high temperatures, several physiological rearrangements occur in cows as they attempt to facilitate heat dissipation and/or reduce metabolic heat production. Following exposure to heat, cattle appear to acclimatize within 2–7 weeks. The failure of homeostasis at high temperatures may lead to reduced productivity or even death. The situation is even worse when humidity adds to high temperature. Livestock with elevated body temperature exhibit lower DMI and growth with less efficiency, reducing profitability for dairy farms in hot and humid climates. Shading of feed and water also offers production advantages. Although several elaborate methods for reducing heat stress in cows have been reported, simple shade materials appear to be the most cost-effective methods that are currently applicable to tropical developing countries. Different materials are being used to provide shade during warm weather. The shade material determines the microclimate—it should be light, strong, durable, weatherproof, good looking and a bad conductor of heat, and free from tendency to condense moisture inside. This review discusses various shade materials and their advantages and disadvantages in different situations. 相似文献
6.
Identification of internal control genes in milk‐derived mammary epithelial cells during lactation cycle of Indian zebu cow
下载免费PDF全文
![点击此处可从《Animal Science Journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
7.
Roop Kishore Ashish Dwivedi Raghuvir Singh R. K. Naresh Vineet Kumar Priyanka Bankoti Dinesh Kumar Sharma Nishant Yadav 《Paddy and Water Environment》2017,15(1):49-58
Weeds caused serious problem on yield reduction of basmati rice worldwide. Losses caused by weeds varied from one country to another, depending on the presence of dominant weeds and the control methods practiced by farmers; therefore, suitable plant population and weed management practices should be adopted. Keeping these in mind, a field experiment was carried out during kharif seasons of 2009 and 2010 at crop Research Centre of SVPUA&T, Meerut, India comprising 4 planting geometries, viz. 20, 30, 40, and 50 hills m?2 as main plot factor, and 5 weed management practices (Butachlor @ 1.0 kg ha?1, Butachlor @ 1.0 kg ha?1 fb (followed by) one hand weeding, Butachlor @ 1.0 kg ha?1 fb Almix @ 4 g ha?1, two hand weedings and weedy check) in a split plot design with 3 replications. Experimental results revealed that plant population of 50 hills m?2 proved superior over that of 20 hills m?2 in respect of weed density, weed dry weight, number of tillers m?2, yield attributes, grain, straw, and biological yields. The maximum grain yield (29.00 and 31.00 q ha?1) and straw yield (51.30 and 52.50 q ha?1) were recorded in 50 hills m?2 followed by 40 hills m?2 during 2009 and 2010, respectively. In respect of nitrogen, phosphorus, and potassium removal, a reverse trend was observed: the highest in 20 hills m?2 followed by 30, 40, and 50 hills m?2. As far as the weed management practices are concerned, both chemical and mechanical methods of weed control were found superior over weedy check. The lowest weed density, dry weight, and highest weed control efficiency, maximum length of panicle?1, number of panicle (m2), and 1000-grain weight and grain yield of 30.40 and 32.60 q ha?1 were recorded with two hand weedings which was at par with Butachlor @ 1.0 kg ha?1 fb one hand weeding over rest of the weed management practices. 相似文献
8.
9.
At least three species of Sarcocystis (S. neurona, S. falcatula, S. speeri) have recently been shown to use opossums of the genus Didelphis as their definitive host. In order to evaluate the evolutionary relationships among Sarcocystis spp. isolates from the Americas, and to determine whether organisms representing the same parasite lineages are transmitted north and south of the Panamanian isthmus, we inferred the phylogenetic relationships from nucleotide sequence variation in parasites isolated from three opossum species (D. virginiana, D. albiventris, D. marsupialis). In particular, we used variation in the 25/396 marker to compare several isolates from Brazil, Argentina, and the United States to each other and to cloned S. neurona and S. falcatula whose morphology and host affinities have been defined in the laboratory. S. neurona was identified from a Brazilian D. albiventris, as well as from North American D. virginiana. Parasites resembling the Cornell isolate of S. falcatula are transmitted both south and north of the Panamanian isthmus by D. albiventris and D. virginiana, respectively. Distinct attributes at two genetic loci differentiated a Brazilian isolate of S. falcatula from all other known parasite lineages. We confirm S. neurona as the causative agent of recently reported neurologic disease in Southern sea otters, Enhydra lutris nereis. And we found that S. speeri could not be compared to the other opossum-derived Sarcocystis isolates on the basis of nucleotide variation at the 25/396 locus. The widespread distribution of certain species of Sarcocystis may derive from their ability to parasitize migratory bird hosts in their intermediate stage. 相似文献
10.
Dual Sarcocystis neurona and Toxoplasma gondii infection was observed in a Northern sea otter from Washington, USA. The animal was found stranded, convulsed, and died shortly thereafter. Encephalitis caused by both S. neurona and T. gondii was demonstrated in histological sections of brain. Immunohistochemical examination of sections with S. neurona specific antisera demonstrated developmental stages that divided by endopolygeny and produced numerous merozoites. PCR of brain tissue from the sea otter using primer pairs JNB33/JNB54 resulted in amplification of a 1100 bp product. This PCR product was cut in to 884 and 216 bp products by Dra I but was not cut by Hinf I indicating that it was S. neurona [J. Parasitol. 85 (1999) 221]. No PCR product was detected in the brain of a sea otter which had no lesions of encephalitis. Examination of brain sections using T. gondii specific antisera demonstrated tachyzoites and tissue cysts of T. gondii. The lesions induced by T. gondii suggested that the sea otter was suffering from reactivated toxoplasmosis. T. gondii was isolated in mice inoculated with brain tissue. A cat that was fed infected mouse brain tissue excreted T. gondii oocysts which were infective for mice. This is apparently the first report of dual S. neurona and T. gondii in a marine mammal. 相似文献