全文获取类型
收费全文 | 1935篇 |
免费 | 94篇 |
国内免费 | 5篇 |
专业分类
林业 | 139篇 |
农学 | 42篇 |
基础科学 | 11篇 |
354篇 | |
综合类 | 240篇 |
农作物 | 120篇 |
水产渔业 | 93篇 |
畜牧兽医 | 835篇 |
园艺 | 57篇 |
植物保护 | 143篇 |
出版年
2023年 | 16篇 |
2022年 | 10篇 |
2021年 | 28篇 |
2020年 | 35篇 |
2019年 | 37篇 |
2018年 | 27篇 |
2017年 | 37篇 |
2016年 | 51篇 |
2015年 | 46篇 |
2014年 | 44篇 |
2013年 | 87篇 |
2012年 | 124篇 |
2011年 | 149篇 |
2010年 | 72篇 |
2009年 | 57篇 |
2008年 | 103篇 |
2007年 | 108篇 |
2006年 | 103篇 |
2005年 | 100篇 |
2004年 | 89篇 |
2003年 | 94篇 |
2002年 | 71篇 |
2001年 | 31篇 |
2000年 | 31篇 |
1999年 | 18篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 13篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 18篇 |
1991年 | 16篇 |
1990年 | 21篇 |
1989年 | 17篇 |
1988年 | 21篇 |
1987年 | 13篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1975年 | 16篇 |
1974年 | 16篇 |
1973年 | 10篇 |
1970年 | 9篇 |
1969年 | 8篇 |
1967年 | 9篇 |
1948年 | 8篇 |
1947年 | 11篇 |
1946年 | 8篇 |
排序方式: 共有2034条查询结果,搜索用时 46 毫秒
41.
Canapp SO Farese JP Schultz GS Gowda S Ishak AM Swaim SF Vangilder J Lee-Ambrose L Martin FG 《Veterinary surgery : VS》2003,32(6):515-523
OBJECTIVE: To evaluate the effects of topical glycyl-L-histidyl-L-lysine tripeptide-copper complex (TCC; Iamin 2% Gel; Procyte Corporation, Redmond, WA) on healing in ischemic open wounds. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Twenty-four adult male Sprague-Dawley rats. METHODS: Rats were divided into 3 groups: topical TCC, topical TCC vehicle (hydroxypropyl-methylcellulose), and no treatment (control). Six-mm-diameter, full-thickness wounds were created within an ischemic bipedicle skin flap on the dorsum of each rat. Each day, for 13 days, wound margins were traced, and the TCC and TCC vehicle groups were treated topically. Tracings were scanned, and wound perimeter and area were calculated. On days 6, 10, and 13, selected wounds were biopsied and analyzed for tumor necrosis factor alpha (TNF-alpha) and matrix metalloproteinases (MMP) 2 and 9. RESULTS: A significant decrease in wound area was seen in the TCC group, but not the vehicle group, when compared with the control group on days 3 to 5, 6 to 9, and 11 to 13 and when TCC was compared with TCC vehicle on days 3 and 9. On day 13, initial wound area had decreased by 64.5% in the TCC group, 45.6% in the vehicle group, and 28.2% in the control group. On days 6, 10, and 13, TCC-treated wounds contained significantly lower concentrations of TNF-alpha and MMP-2 and MMP-9 than control wounds. CONCLUSION: Topical TCC resulted in accelerated wound healing in ischemic open wounds. CLINICAL RELEVANCE: Topical TCC is an effective stimulant of healing of ischemic open wounds in rats and may have an application for the treatment of chronic wounds in other species. Clinical evaluation of topical TCC is warranted. 相似文献
42.
Germán Cantón Paul Bartley Kathryn Bartley Helen Todd Francesca Chianini Frank Katzer 《Veterinary immunology and immunopathology》2013,151(3-4):342-347
Pro-inflammatory cytokines (particularly IL-12) are important for initiating protective T helper 1 (Th1)-type immune responses and hence vital for combating intracellular infections and tumours. In situ hybridization (ISH) provides a powerful diagnostic tool allowing the identification and localization of cells producing these mediators in fixed tissues. The objective of this work was to produce a bovine IL-12p40 probe that allows detection of IL-12p40 mRNA in fixed tissues from different ruminant species. The RNA probe sequence is 447 bp in length and from a region with high cross-species-sequence homology (>97.3% homology) to the ovine, cervine, caprine and bubaline IL-12p40 genes. ISH was carried out on paraformaldehyde fixed tissues collected from cattle, sheep and goats. The probe was efficient in identifying IL-12p40 expressing cells in fixed tissues from all these species. In conclusion, the IL-12p40 probe was efficient in identifying and localizing cells that express IL-12p40, and provides a good immuno-diagnostic technique to characterize immune responses in fixed tissues. 相似文献
43.
44.
45.
46.
John M Sykes Michael M Garner Leah L Greer Nancy P Lung Rob L Coke Frank Ridgley Mitch Bush Richard J Montali Ben Okimoto Robert Schmidt Jack L Allen Bruce A Rideout Patricia A Pesavento Edward C Ramsay 《Journal of zoo and wildlife medicine》2007,38(2):300-308
Oral eosinophilic granulomas were diagnosed in 16 tigers (Panthera tigris). All lesions were located on the hard or soft palate and typically consisted of flat or slightly raised circular ulcers. Histologic features of these lesions were essentially identical to those seen in oral eosinophilic granulomas of domestic cats and dogs. No clinical signs were noted in eight cases, though various degrees of inappetence, excessive salivation, and dysphagia were noted in the other eight tigers. Six cases were not treated. Treatment for the remaining 10 cases centered on corticosteroids and additional treatments included surgical removal, cryotherapy, antibiotics, and chlorpheniramine. Treatment with corticosteroids did appear to be effective in some cases, though lesions would worsen after cessation of therapy and no cases were cured. In addition, three cases developed complications possibly related to this corticosteroid therapy. The etiology of these lesions remains unknown, though an underlying allergic condition is likely. 相似文献
47.
Alex Tsungyu Hung Brian Joseph Leury Matthew Allen Sabin Cherie Louise Collins Frank Rowland Dunshea 《Tropical animal health and production》2014,46(8):1483-1489
Chromium (Cr) is an essential mineral element and has been used in pig diets to improve growth performance, insulin sensitivity, immune response and carcase traits and to reduce heat or other stress responses. The aims of thiss study were to determine the impact of nano-sized chromium tripicolinate (nCrPic) on growth performance, feed efficiency and carcase characteristics of finisher gilts during the summer period. A total of 60 finisher Large White x Landrace gilts were stratified on initial weight and then within strata randomly allocated into two treatment groups in three replicates during mid-summer for 28 days. All pigs were housed in individual pens and had ad libitum access to feed and water. Pigs were fed either a control finisher diet (wheat-based diet containing 13.8 MJ digestible energy (DE) per kilogram and 0.56 g available lysine/MJ DE) or a control diet containing 400 ppb Cr as nCrPic. Dietary nCrPic supplementation increased feed intake by 6 % over the entire study (P?=?0.05). In particular, dietary nCrPic increased average daily feed intake (ADFI) by 8 % (P?=?0.02) during the final 2 weeks of the study. Moreover, dietary nCrPic tended to improve average daily feed (ADFI) over the entire study (P?=?0.09). However, there were no significant effects of nCrPic on feed conversion ratio (FCR), final weight, hot standard carcase weight (HCWT), P2 depth or dressing percentage. Plasma cortisol was decreased by 25 % (P?=?0.06) by dietary nCrPic supplementation. However, there were no effects of nCrPic on plasma glucose, insulin and nonesterified fatty acids (NEFA), might because of the higher feed intake. In conclusion, this study demonstrates that dietary nCrPic supplementation at 400 ppb can increase feed intake in finisher gilts during mid-summer, suggesting that nCrPic can ameliorate some of the negative effects of heat stress in pigs, possibly via decreased of circulating cortisol. 相似文献
48.
Frank LA Hnilica KA May ER Sargent SJ Davis JA 《American journal of veterinary research》2005,66(2):256-259
OBJECTIVE: To evaluate effects of trimethoprim-sulfamethoxazole (T/SMX) on thyroid function in dogs. ANIMALS: 6 healthy euthyroid dogs. PROCEDURE: Dogs were administered T/SMX (14.1 to 16 mg/kg, PO, q 12 h) for 3 weeks. Blood was collected weekly for 6 weeks for determination of total thyroxine (TT4), free thyroxine (fT4), and canine thyroid-stimulating hormone (cTSH) concentrations. Schirmer tear tests were performed weekly. Blood was collected for CBC prior to antimicrobial treatment and at 3 and 6 weeks. RESULTS: 5 dogs had serum TT4 concentrations equal to or less than the lower reference limit, and 4 dogs had serum fT4 less than the lower reference limit after 3 weeks of T/SMX administration; cTSH concentrations were greater than the upper reference limit in 4 dogs. All dogs had TT4 and fT4 concentrations greater than the lower reference limit after T/SMX administration was discontinued for 1 week, and cTSH concentrations were less than reference range after T/SMX administration was discontinued for 2 weeks. Two dogs developed decreased tear production, which returned to normal after discontinuing administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that administration of T/SMX at a dosage of 14.1 to 16 mg/kg, PO, every 12 hours for 3 weeks caused decreased TT4 and fT4 concentrations and increased cTSH concentration, conditions that would be compatible with a diagnosis of hypothyroidism. Therefore, dogs should not have thyroid function evaluated while receiving this dosage of T/SMX for >2 weeks. These results are in contrast to those of a previous study of trimethoprim-sulfadiazine. 相似文献
49.
Frank N Sommardahl CS Eiler H Webb LL Denhart JW Boston RC 《American journal of veterinary research》2005,66(6):1032-1038
OBJECTIVE: To evaluate glucose and lipid metabolism in healthy adult horses administered levothyroxine sodium (L-T4). ANIMALS: 12 healthy adult mares. PROCEDURE: 8 horses received an incrementally increasing dosage of L-T4 (24, 48, 72, or 96 mg of L-T4/d) for weeks 1 to 8. Each dose was provide between 7 AM and 8 AM in the morning grain meal for 2 weeks. Four additional horses remained untreated. Serum concentrations of nonesterified fatty acids, triglyceride (TG), total cholesterol (TC), and very-low-density lipoprotein (VLDL) were measured and composition of VLDL examined in samples obtained between 8 AM and 9 AM at weeks 0, 2, 4, 6, and 8. Glucose dynamics were assessed by use of a combined IV glucose-insulin tolerance test (IVGITT) conducted before and at the end of the 8-week treatment period. Data for each combined IVGITT were interpreted by use of the minimal model. RESULTS: Plasma TG, TC, and VLDL concentrations significantly decreased over time in treated horses. At the completion of the 8-week treatment period, mean plasma VLDL concentration was 46% of the mean value for week 0 in treated horses. Insulin sensitivity significantly increased (> 2-fold) in treated horses, but glucose effectiveness and net insulin response were not affected. Levothyroxine sodium significantly increased the rate of insulin disposal. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of L-T4 decreases blood lipid concentrations, improves insulin sensitivity, and increases insulin disposal in horses. Levothyroxine sodium may have potential as a treatment for horses with reduced insulin sensitivity. 相似文献