全文获取类型
收费全文 | 1303篇 |
免费 | 79篇 |
专业分类
林业 | 61篇 |
农学 | 28篇 |
基础科学 | 3篇 |
220篇 | |
综合类 | 138篇 |
农作物 | 90篇 |
水产渔业 | 76篇 |
畜牧兽医 | 688篇 |
园艺 | 22篇 |
植物保护 | 56篇 |
出版年
2023年 | 12篇 |
2022年 | 16篇 |
2021年 | 23篇 |
2020年 | 29篇 |
2019年 | 39篇 |
2018年 | 31篇 |
2017年 | 32篇 |
2016年 | 34篇 |
2015年 | 25篇 |
2014年 | 35篇 |
2013年 | 58篇 |
2012年 | 78篇 |
2011年 | 116篇 |
2010年 | 40篇 |
2009年 | 44篇 |
2008年 | 83篇 |
2007年 | 73篇 |
2006年 | 73篇 |
2005年 | 85篇 |
2004年 | 86篇 |
2003年 | 75篇 |
2002年 | 59篇 |
2001年 | 18篇 |
2000年 | 9篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 11篇 |
1996年 | 10篇 |
1995年 | 10篇 |
1994年 | 14篇 |
1993年 | 7篇 |
1992年 | 11篇 |
1991年 | 10篇 |
1990年 | 5篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1975年 | 5篇 |
1972年 | 6篇 |
1970年 | 4篇 |
1969年 | 4篇 |
1967年 | 4篇 |
1966年 | 6篇 |
1959年 | 4篇 |
1953年 | 4篇 |
排序方式: 共有1382条查询结果,搜索用时 0 毫秒
991.
992.
993.
The negative acute phase response of serum transthyretin following Streptococcus suis infection in the pig 总被引:3,自引:0,他引:3
Campbell FM Waterston M Andresen LO Sorensen NS Heegaard PM Eckersall PD 《Veterinary research》2005,36(4):657-664
Transthyretin (TTR) is a serum protein which is a negative acute phase reactant in humans and levels of TTR are routinely measured as an indicator of health status. Such tests have yet to be established for the pig. In order to measure serum TTR in the pig during an acute phase response an assay was developed using anti-human TTR antibodies which cross reacted with porcine TTR. The assay had a detection limit of 32 microg/mL while the mean concentration of transthyretin measured in healthy pig serum was 302 +/- 8 microg/mL (n = 63). There was no significant difference in the serum concentration of TTR in three different age groups from 10 to 25 weeks. Following Streptococcus suis type 2 infection transthyretin showed a negative acute phase response with serum concentrations reaching a significantly lower level at two days following infection. 相似文献
994.
Fine-needle aspiration of the spleen is a useful method for evaluation of reactive, inflammatory, and neoplastic disorders, particularly those that involve the hematopoietic system. Interpretation of splenic aspirates is enhanced by concurrent evaluation of blood and other hemic tissues. 相似文献
995.
George M Barrington John M Gay Inge S Eriks William C Davis James F Evermann Carlene Emerson Jennifer L O'Rourke Mary J Hamilton Daniel S Bradway 《Journal of veterinary diagnostic investigation》2003,15(2):195-200
As part of investigating diagnostic strategies for Mycobacterium avium subsp. paratuberculosis (Map), serial results from polymerase chain reaction (PCR) on extraintestinal tissues (blood, milk, and liver) were compared with those from more conventional detection methods including serum enzyme-linked immunosorbent assay (ELISA), fecal culture, and fecal PCR. Three cows previously identified as being subclinically infected with Map were selected for the study. Blood, milk, and feces were collected daily and liver biopsies were obtained weekly for a 30-day period. Unexpectedly, a substantial daily variation in serum ELISA sample to positive (S/P) ratios was observed in all 3 cows. In contrast, fecal culture results were consistently positive. However, whereas fecal culture colony counts were consistently high for 2 cows throughout the study, colony counts from the third cow varied from day to day. Diagnostic sensitivity of PCR for fecal, blood, milk, and liver samples in these advanced subclinically infected cows was 87%, 40%, 96%, and 93%, respectively. 相似文献
996.
Mary Ann Amos Anne H Nielsen Alvar A Werder 《Comparative immunology, microbiology and infectious diseases》1981,4(1):21-28
Germfree derived CFWwd mice were inoculated with tumor cells from chickens with Marek's disease and observed for any long term effect. Nineteen per cent of these animals developed tumors whereas the incidence in control animals was 0.2%. Of those animals which developed tumors, 62% of the animals were observed to have ataxia before tumor development. Marek's disease herpesvirus was never observed in any of the murine tumors. 相似文献
997.
Harbo SJ Barrington GM Allen AJ Sample GL Parish SM Hamilton MJ Davis WC 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2004,33(3):163-167
A 2-month-old Angus heifer was presented to Washington State University Veterinary Teaching Hospital for generalized peripheral lymphadenopathy and mild anorexia. Results of a CBC revealed marked lymphocytosis consisting primarily of large, atypical lymphocytes with cleaved, reniform nuclei. A presumptive diagnosis of sporadic juvenile lymphoma was made. To confirm these findings, a prescapular lymph node was submitted for histopathology, immunochemistry, and flow cytometric analysis. Peripheral blood also was analyzed by flow cytometry. Phenotypic characterization of lymph node and peripheral blood cell populations verified the calf had the B-cell form of sporadic juvenile lymphoma. The results of this investigation expand the phenotypic characterization of neoplastic lymphocytes in sporadic juvenile lymphoma. 相似文献
998.
Thompson MF Scott-Moncrieff JC Brooks MB 《Journal of the American Animal Hospital Association》2004,40(6):446-454
Thirteen dogs with primary immune-mediated hemolytic anemia received fresh-frozen plasma within 12 hours of admission, in addition to unfractionated heparin and other therapies, such as prednisone, azathioprine, and packed red blood cell transfusion. Antithrombin activity was quantified prior to transfusion and at 30 minutes and 48 hours after transfusion. Plasma antithrombin activity did not change significantly after a single plasma transfusion. There were no deaths in the first 48 hours of treatment. Thromboembolism was identified at necropsy in six of 10 dogs that died within 12 months of admission. There was no significant difference in the incidence of thromboembolism between the current treatment group and a historical control group. 相似文献
999.
Liptak JM Dernell WS Straw RC Jameson VJ Lafferty MH Rizzo SA Withrow SJ 《Veterinary surgery : VS》2004,33(5):457-467
OBJECTIVE: To evaluate postoperative complications, limb function, and tumor control after intercalary resection and reconstruction for preservation of limb and joint function in dogs with high-grade malignant tumors of diaphyseal bone. STUDY DESIGN: Retrospective study. ANIMALS: Seventeen client-owned dogs. METHODS: The bone tumor database and medical records were reviewed (1986-2002) for dogs with diaphyseal tumors treated with intercalary resection and reconstruction with either an allograft or irradiated autograft. Clinical presentation, diagnostic findings, surgical management, and outcome were determined from medical records and telephone interviews with veterinarians and owners. Statistical analyses included chi2 to test associations between intra- and postoperative variables with complications, and Kaplan-Meier survival analysis for disease-free interval, metastasis-free interval (MFI), and median survival time. RESULTS: Intercalary limb-sparing surgery was performed in 17 dogs with diaphyseal tumors: osteosarcoma (OSA) (15), histiocytic sarcoma (1), and solitary metastasis from a pulmonary adenocarcinoma (1). One dog was excluded from further analysis when the spared limb was amputated 4 days postoperatively because of incomplete tumor resection. In 16 dogs, limb function was good to excellent. Complications occurred in 5 dogs (31.3%) and included superficial infection in 2 dogs (12.5%) and implant failure in 4 dogs (25%). All implant failures occurred in the ulna and there was a significant association between implant failure and non-cemented allografts (P=.042). Non-union of 1 or both osteotomies was diagnosed in 10 dogs (83.3%) and, despite lack of clinical signs in all cases, was significantly associated with the use of intracavitary locally released cisplatin (P=.046) and cemented intercalary grafts (P=.046). Local tumor recurrence was diagnosed in 1 dog (6.3%) and metastatic disease in 12 dogs (75.0%), including 10 dogs with OSA. The median MFI was 137 days. The local disease-free and overall limb-salvage rate was 94% and 100%, respectively. Overall median survival time was 393 days and the median survival time for dogs with OSA was 449 days. CONCLUSION: Intercalary limb-sparing surgery results in better postoperative limb function with fewer and less severe complications than historical reports of dogs treated with non-intercalary limb-sparing surgery. CLINICAL RELEVANCE: In dogs with diaphyseal tumors, intercalary limb-sparing surgery preserves normal joint function and results in good to excellent limb use with few complications and good local tumor control. 相似文献
1000.
OBJECTIVE: To quantify long-term bone adaptation after stable cemented total hip arthroplasty (cTHA) in dogs. STUDY DESIGN: Clinical study. ANIMALS: Fourteen dogs. METHODS: Femoral specimens were collected from client-owned dogs that were donated after death because of causes unrelated to their cTHA. Mean (+/-SEM) dog age was 11.4+/-0.7 years and implant duration was 5.3+/-0.7 years. Implant stability was established from radiographic signs and gross mechanical stability. Femurs were evaluated at 3 levels based on implant length: proximal stem (PS), mid-stem (MS), and distal to stem (DS). Cortical area, medullary area, and porosity were measured at each level. Implanted femurs were compared to contralateral nonimplanted femurs. RESULTS: Cortical area and cortical porosity were significantly increased in implanted femurs compared to nonimplanted femurs. Cortical area was increased at the MS and DS levels, and porosity was increased at the PS and MS levels in implanted femurs. Porosity was greatest in the endosteal region at the PS and MS levels in implanted femurs. CONCLUSIONS: Significant differences in femoral geometry and cortical porosity were detected after long-term stable cTHA. Net bone loss proximally and increased bone mass distally support stress shielding as a important mechanical factor associated with bone adaptation. Distribution of porosity shifts to endosteal regions after long-term cTHA. CLINICAL RELEVANCE: Significant site-specific femoral adaptation occurs in response to stable cTHA and may precede implant loosening. 相似文献