全文获取类型
收费全文 | 273篇 |
免费 | 17篇 |
专业分类
林业 | 6篇 |
农学 | 2篇 |
基础科学 | 1篇 |
39篇 | |
综合类 | 27篇 |
农作物 | 15篇 |
水产渔业 | 10篇 |
畜牧兽医 | 186篇 |
园艺 | 1篇 |
植物保护 | 3篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 5篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 3篇 |
2013年 | 22篇 |
2012年 | 9篇 |
2011年 | 15篇 |
2010年 | 9篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 16篇 |
2006年 | 14篇 |
2005年 | 6篇 |
2004年 | 17篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 8篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 12篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1972年 | 2篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1967年 | 3篇 |
1966年 | 1篇 |
1947年 | 1篇 |
1884年 | 1篇 |
排序方式: 共有290条查询结果,搜索用时 609 毫秒
71.
Pinto C Santos VM Dinis J Peleteiro MC Fitzgerald JM Hawkes AD Smith BL 《The Veterinary record》2005,157(25):805-810
Outbreaks of pithomycotoxicosis (facial eczema), a hepatogenous photosensitisation caused by the mycotoxin sporidesmin, have affected ruminants in the Azores Islands of Portugal after warm, humid periods during late summer and autumn. Twenty-two outbreaks were recorded in cattle between 1999 and 2001, affecting 11.4 per cent of the animals in the affected herds, and in 2000 there was an outbreak in one sheep flock in which more than 20 per cent of the sheep died. The clinical signs included decreases in milk production, weight loss, photosensitisation and its sequelae, including death. The animals had high activities of gamma glutamyltransferase in their serum, and icterus and severe liver disease, including biliary hyperplasia and fibrosis, were found postmortem. The characteristic spores of the toxigenic saprophytic fungus Pithomyces chartarum were found on grass; all 381 isolates of the fungus were toxigenic for sporidesmin by elisa, and the results were confirmed by high-performance liquid chromatography analysis. Cattle from farms at greatest risk of pithomycotoxicosis were protected by supplementing their concentrate feed with zinc oxide, or using a slow-release intraruminal zinc bolus. 相似文献
72.
Sessions DR Reedy SE Vick MM Murphy BA Fitzgerald BP 《Journal of animal science》2004,82(8):2321-2328
Peripheral insulin resistance is the failure of proper cellular glucose uptake in response to insulin. Insulin resistance and hyperinsulinemia are associated with several disease states in the horse and reproductive function disturbances in humans, including polycystic ovarian syndrome. To test the hypothesis that insulin resistance (IR) and hyperinsulinemia disrupt the estrous cycle in mares, two experiments were conducted to first develop a model to induce IR and to then examine the effect of this model on the duration of the estrous cycle. In Exp. 1, a hyperinsulinemic-euglycemic clamp (HEC) procedure was performed on seven mares to determine insulin sensitivity before and immediately following infusion of a heparinized lipid solution. The HEC procedure was repeated 1 wk after lipid infusion. Mares developed IR following the lipid infusion (P < 0.05), and some individuals maintained IR for up to 1 wk. Mares also exhibited increased blood insulin both immediately following treatment and 1 wk later (P < 0.05). In Exp. 2, induction of insulin resistance by lipid solution was not accompanied by changes in circulating concentrations of luteinizing hormone, and duration of the luteal phase, compared with the duration of untreated luteal phases. Nonetheless, lipid infusion and the resultant insulin resistance were associated with an increased interovulatory period (P < 0.05), and peak concentrations of progesterone (P < 0.05) were higher during the treated vs. untreated luteal phases of the estrous cycle. The results from the preliminary study suggest that infusion of a lipid solution may induce transient insulin resistance and hyperinsulinemia. The resulting insulin resistance and hyperinsulinemia may modify characteristics of the estrous cycle, perhaps at the level of the ovary. 相似文献
73.
The motility outcomes of boar semen frozen with newly developed freezing techniques using a new unique freezing technology (UFT) compared with traditional liquid nitrogen methodology were investigated with the intent of improving current fertility outcomes using semen. The UFT is an electronically controlled cooling chamber that houses an organic fluid bath that can be maintained at temperatures below 0 degrees C without solidifying to freeze samples. Four ejaculates from four different boars were collected for this trial. Samples were handled consistently during the pre- and post-freeze processing. From each ejaculate, samples were separated into eight cryopreservation treatment groups, six UFT variations and two control liquid nitrogen groups, immediately before freezing, in replicates of two. After the initial cryopreservation was complete, all samples were stored in liquid nitrogen for at least 48 h. Post-thaw motilities and original motility return percentages were assessed on a random, individual-sample basis. After the initial evaluations, samples from two boars were recollected and frozen using the UFT for breeding purposes. Four sows were bred with the UFT frozen semen to confirm fertility capability. When assessing the individual UFT techniques, all of six UFT techniques had improved post-thaw motilities. However, treatments F (micro = 29%, return micro = 37%) and J (micro = 27%, return micro = 34%) showed the highest statistical improvement for post-thaw (p < 0.05) and original motility percent returns (p < 0.05) when compared with either the control cryo-tube (micro = 15%, return micro = 19%) or straw groups (micro = 12%, return micro = 16%). The UFT semen had a 50% conception rate, with an average of seven piglets from the sows that farrowed. Our preliminary data suggest a higher motility return with a slower pre-freeze phase below the freezing point before the acceleration to liquid nitrogen temperatures. The preliminary data suggest that the UFT could be utilized as a potential cryopreservation option for boar semen. 相似文献
74.
H M Elsheikha S D Fitzgerald B M Rosenthal L S Mansfield 《Journal of veterinary diagnostic investigation》2004,16(4):352-356
Opossums (Didelphis virginiana) are exposed to a wide range of coccidia through feeding on a variety of foods, including, but not limited to, carrion, insects, and nestling birds. Abundant D. virginiana populations in urban and suburban areas can be important reservoirs of parasitic infection because of their profuse and prolonged excretion of the sporocysts of several species of Sarcocystis, their omnivorous diet, and their relatively long life span. This report describes 2 adult female opossums found to be simultaneously infected with the tissue cysts of Besnoitia darlingi, sarcocysts of Sarcocystis inghami, as well as with the intestinal sporocysts of S. neurona. Cysts typical of B. darlingi based on gross, histological, and ultrastructural characteristics were disseminated throughout the visceral organs, musculature, ears, and skin. The S. neurona and B. darlingi infections were confirmed by comparative sequence analysis of polymerase chain reaction-amplified diagnostic genetic loci. Sarcocysts of S. inghami are also described. Such examples of multiple parasitic infections show that concurrent infections occur naturally. The propensity for species to coexist should be considered in the differential diagnosis of tissue cyst-forming coccidian protozoa and may have important epidemiological and evolutionary implications. 相似文献
75.
Wilson K Rumbeiha Jayaraj A Francis Scott D Fitzgerald Muraleedharan G Nair Kate Holan Kwasi A Bugyei Heather Simmons 《Journal of veterinary diagnostic investigation》2004,16(6):527-541
This study was conducted with 3 objectives in mind: first, to identify the toxic fraction (aqueous or organic) in leaves and flowers; second, to identify diagnostic marker(s) of toxicosis in cats; and, third, to evaluate the morphologic effects of intoxication. The study was conducted in 2 phases. Phase 1 was to identify which extract, organic or aqueous, was nephrotoxic and also to determine the appropriate dose for use in the phase 2 studies. Results indicated that only the aqueous extracts of leaves and flowers were nephrotoxic and pancreotoxic. To identify the proximate toxic compound, cats in the phase 2 study were orally exposed to subfractions of the aqueous flower extract, 1 subfraction per cat. Results confirmed vomiting, depression, polyuria, polydipsia, azotemia, glucosuria, proteinuria, and isosthenuria as toxic effects of the Easter lily plant. Another significant finding in serum was elevated creatinine kinase. Significant histologic kidney changes included acute necrosis of proximal convoluted tubules and degeneration of pancreatic acinar cells. Renal ultrastructural changes included swollen mitochondria, megamitochondria, edema, and lipidosis. Subfraction IIa3 of the aqueous floral extract contained most of the toxic compound(s). These studies reproduced the clinical disease, identified the most toxic fraction of the Easter lily, and helped characterize the clinical pathology, histopathology, and ultrastructural pathology associated with the disease. 相似文献
76.
77.
Sebastian MM Bernard WV Riddle TW Latimer CR Fitzgerald TD Harrison LR 《Veterinary pathology》2008,45(5):710-722
An epidemic of early fetal loss (EFL), late fetal loss (LFL), fibrinous pericarditis, and unilateral uveitis which occurred during the spring of 2001, are together now known as the mare reproductive loss syndrome (MRLS). A similar epidemic with less intensity was reported during the same period of time from southern Ohio, West Virginia, and Tennessee. The same syndrome with lesser intensity recurred in 2002. The estimated economic loss from the syndrome in 2001 and 2002 together was approximately $500 million. Both EFL and LFL were characterized by the absence of specific clinical signs in aborting mares. Nonhemolytic Streptococcus spp. and Actinobacillus spp. accounted for 65% of the organisms isolated from fetuses submitted for a postmortem during the MRLS period in 2001 and 2002. The pathologic findings in fetoplacental units of LFL included bronchopneumonia and funisitis, and there were no findings in EFL. Epidemiologic studies conducted in 2001 suggested an association between the presences of eastern tent caterpillars (ETC) in pastures with MRLS. Experimental studies in pregnant mares by exposure to ETC, or administration by stomach tube or with feed material, reproduced EFL and LFL. Similar experimental studies in mouse, rats, and goats with ETC were unsuccessful. Currently, 2 hypotheses are proposed for MRLS. One hypothesis proposes that an ETC-related toxin with secondary opportunistic bacterial invasion of the fetus leads to MRLS. The second hypothesis suggests that a breach of gastrointestinal mucosal integrity by hairs of ETC leads to a bacteremia and results in MRLS. In 2004, a similar equine abortion storm was reported from Australia and caterpillar exposure was identified as a risk factor for the abortion. In 2006, the syndrome was observed in Florida and New Jersey. 相似文献
78.
Current strains of fowlpox virus (FWPV) carrying circulating reticuloendotheliosis virus (FWPV-REV) sequence are becoming more pathogenic to poultry. This is evidenced by the fact that vaccination with current available FWPV vaccines provides limited protection against them. To characterize REV insertions in a collection of both older and more recent field isolates, we developed three different types of adjacent oligoprobes and primer sets from specific genomic locations of FWPV and REV: REV-ENV (accession no. K02537, 1382-2260), FWPV-REV integration site (accession no. AF006064, 86-1328), FWPV (accession no. AF198100, 232461-232670), and REV-LTR (accession no. V01204, 305-496). The data indicated that the primers from the REV-ENV region and the TaqMan probes specifically targeted REV-ENV sequences of FWPV-REV strains. Furthermore, the strains were differentiated based on quantitative melting temperature (T(m)) of their amplified products using FRET-based probes. The amplified products were further characterized by sequencing and multiple sequence alignment analysis. The results suggest that integrated REV-ENV sequences are both common and mostly conserved in field isolates. However, the minor variations found within the short-targeted ENV sequence from FWPV-REV strains suggest that these strains could have either undergone periodic point mutational changes or integration with different REV-ENV subtypes. 相似文献
79.
E Wong I Mikaelian M Desnoyers G Fitzgerald 《Journal of zoo and wildlife medicine》1999,30(4):584-586
A free-ranging juvenile female red-tailed hawk (Buteo jamaicensis) that was unable to fly was admitted to a rehabilitation center and died 1 day later. Hematology and serum chemistry abnormalities included moderate regenerative anemia, elevated creatine kinase, and hyperphosphatemia. Necropsy revealed a generalized steatitis, and histology showed a necrotizing and granulomatous pansteatitis with intralesional pigment compatible with ceroid. There was also moderate diffuse myodegeneration, mild multifocal cardiomyopathy, and mild multifocal hepatic necrosis. These changes and lesions resemble those caused by vitamin E deficiency in mammals and fish-eating birds. 相似文献
80.