全文获取类型
收费全文 | 741篇 |
免费 | 51篇 |
专业分类
林业 | 15篇 |
农学 | 16篇 |
113篇 | |
综合类 | 96篇 |
农作物 | 25篇 |
水产渔业 | 41篇 |
畜牧兽医 | 389篇 |
园艺 | 33篇 |
植物保护 | 64篇 |
出版年
2023年 | 8篇 |
2022年 | 8篇 |
2021年 | 8篇 |
2020年 | 15篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 14篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 15篇 |
2013年 | 41篇 |
2012年 | 43篇 |
2011年 | 47篇 |
2010年 | 14篇 |
2009年 | 23篇 |
2008年 | 55篇 |
2007年 | 39篇 |
2006年 | 48篇 |
2005年 | 40篇 |
2004年 | 56篇 |
2003年 | 51篇 |
2002年 | 33篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1994年 | 7篇 |
1993年 | 10篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1989年 | 7篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1978年 | 6篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 9篇 |
1972年 | 5篇 |
1970年 | 9篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1965年 | 3篇 |
1958年 | 3篇 |
1954年 | 3篇 |
1953年 | 4篇 |
排序方式: 共有792条查询结果,搜索用时 62 毫秒
21.
OBJECTIVE: To describe the demographic and clinical characteristics of a population of geriatric horses. DESIGN: Retrospective study. ANIMALS: 467 horses that were > or = 20 years of age. PROCEDURE: Medical records of 539 geriatric horses that were evaluated at a university large animal hospital between 1989 and 1999 were reviewed. Data collected included signalment, reason for evaluation, specific diagnoses, surgical procedures, inpatient or outpatient care, duration of hospitalization, and outcome. RESULTS: 467 horses met the criteria for inclusion in the study. Horses that were > or = 20 years of age comprised 2.2 and 12.5% of horses evaluated during 1989 and 1999, respectively. Pony breeds were significantly overrepresented in the > or = 30-years-of-age group. Gastrointestinal tract, musculoskeletal, and respiratory tract problems were most frequently reported. Colic was the most common clinical sign, followed by lameness. Diagnoses made most frequently included pituitary dysfunction, strangulating lipoma of the small intestine, laminitis, heaves, large colon impaction, and gastric ulcers. Pituitary dysfunction was significantly more prevalent in horses that were > 30 years of age. Laminitis was significantly associated with the presence of pituitary dysfunction. CONCLUSIONS AND CLINICAL RELEVANCE: It was difficult to assess association of age with illnesses identified in these horses. Demographic data and information regarding common diseases of horses that are > or = 20 years of age are limited but will become increasingly important as this geriatric population increases. 相似文献
22.
OBJECTIVE: To describe the demographic and clinical characteristics, management practices, and owner perception of a population of geriatric horses, and to compare these data with findings in a group of younger horses. DESIGN: Original study. ANIMALS: 218 horses. PROCEDURE: Data were collected via a survey tool from owners of 165 horses that were > or = 20 years of age and 53 horses that were < 20 years of age. RESULTS: Compared with young horses, the geriatric group included a significantly greater number of ponies; geriatric horses were also more likely to have a history of colic, dental disease, tumors, lameness, and pituitary disease, but not laminitis, diarrhea, allergies, respiratory tract disease, thyroid disease, or fractures. Horses that had participated in Western equestrian disciplines were more likely to have a history of lameness. Among old horses, those with pituitary dysfunction were more likely to have a history of laminitis than those without pituitary dysfunction. Geriatric horses were more likely to have long hair and shedding abnormalities than were younger horses. Owners perceived their horses as old at approximately 22 years of age. In horses older than 16.5 years of age, age was a negative factor in the purchase of horses. CONCLUSIONS AND CLINICAL RELEVANCE: Geriatric and young horses share some similar health problems, but old horses have distinct health problems and veterinary medical requirements. The management and athletic history of horses may influence health as they age. 相似文献
23.
Puccio M Marino DJ Stefanacci JD McKenna B 《Journal of the American Animal Hospital Association》2003,39(5):473-478
A retrospective study was performed describing the clinical presentations, radiographic findings, and surgical outcomes of 17 dogs (18 elbows) following medial coronoidectomy for the treatment of elbow joint incongruity as a sole disease entity. Complete resolution of lameness was achieved in 100% of the cases. The mean radiographic arthrosis grade progressed in 70% of the cases. Results of this study indicate that resolution of clinical lameness may be achieved with medial coronoidectomy in dogs with elbow incongruity; however, progression of degenerative joint disease with unknown, long-term clinical significance can be expected after surgery. 相似文献
24.
Sirinarumitr K Sirinarumitr T Johnston SD Sarkar DK Kustritz MV 《American journal of veterinary research》2002,63(4):495-498
OBJECTIVE: To determine the effect of finasteride on programmed cell death (apoptosis) of prostatic cells during prostatic involution in dogs with benign prostatic hypertrophy (BPH). ANIMALS: 9 dogs with BPH. PROCEDURE: Dogs were randomly assigned to treatment or control groups. Treatment dogs (n = 5) were administered finasteride (0.1 to 0.5 mg/kg, PO, q 24 h) for 16 weeks, whereas the 4 control dogs were administered an inert compound. Prostatic cells from the prostatic fluid portion of the ejaculate of treatment and control dogs were obtained before and 1, 2, 3, 4, 8, and 16 weeks after initiation of treatment. Cells were concentrated by use of centrifugation. Prostatic cells were examined for indications of apoptosis by use of a terminal deoxyribonucleotidyl transferase-mediated deoxyuracil triphosphate nick-end labeling technique. After receiving the inert compound for 16 weeks, the 4 control dogs were administered finasteride for 16 weeks, and evaluations were repeated. RESULTS: Percentage of apoptotic prostatic cells in ejaculated prostatic fluid of treatment dogs increased significantly (from 9% before treatment to 33, 31, 26, and 27% after 1, 2, 3, and 8 weeks of treatment, respectively). There was no significant change in percentage of apoptotic prostatic cells in the ejaculated prostatic fluid of control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Finasteride-induced prostatic involution appears to be via apoptosis in dogs with BPH. Finasteride treatment of dogs with BPH causes prostatic involution by apoptosis rather than necrosis. 相似文献
25.
26.
Lee IT Levy JK Gorman SP Crawford PC Slater MR 《Journal of the American Veterinary Medical Association》2002,220(5):620-622
OBJECTIVE: To determine prevalence of FeLV infection and serum antibodies against feline immunodeficiency virus (FIV) in unowned free-roaming cats. DESIGN: Cross-sectional serologic survey. ANIMALS: 733 unowned free-roaming cats in Raleigh, NC, and 1,143 unowned free-roaming cats in Gainesville, Fla. RESULTS: In Raleigh, overall prevalence of FeLV infection was 5.3%, and overall seroprevalence for FIV was 2.3%. In Gainesville, overall prevalence of FeLV infection was 3.7%, and overall seroprevalence for FIV was 4.3%. Overall, FeLV prevalence was 4.3%, and seroprevalence for FIV was 3.5%. Prevalence of FeLV infection was not significantly different between males (4.9%) and females (3.8%), although seroprevalence for FIV was significantly higher in male cats (6.3%) than in female cats (1.5%). CONCLUSIONS AND CLINICAL RELEVANCE: Prevalence of FeLV infection and seroprevalence for FIV in unowned free-roaming cats in Raleigh and Gainesville are similar to prevalence rates reported for owned cats in the United States. Male cats are at increased risk for exposure to FIV, compared with female cats. 相似文献
27.
28.
29.
30.
J. Jović T. Cvrković M. Mitrović S. Krnjajić Margaret G. Redinbaugh R. C. Pratt R. E. Gingery S. A. Hogenhout I. Toševski 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(1):85-89
Maize redness (MR), a disease causing midrib, leaf and stalk reddening and abnormal ear development in maize, has been reported
from Serbia, Romania and Bulgaria for 50 years. Recent epiphytotics reduced yields by 40%–90% in southern Banat, Serbia. MR
was recently associated with the presence of the stolbur phytoplasma, although the epidemiology of the disease remained unknown.
Diseased fields in southern Banat were surveyed for potential vectors of the phytoplasma during 2005 and 2006, and high populations
of Reptalus panzeri were found. In affected fields, 20% of the R. panzeri individuals and 85% of symptomatic maize plants carried the stolbur phytoplasma. When stolbur phytoplasma-infected R. panzeri were introduced into insect-free mesh cages containing healthy maize plants, midrib and leaf reddening developed on 48% of
plants and stolbur phytoplasma was detected in 90% of the symptomatic plants. No symptoms or phytoplasma-positive plants were
found in cages without insects. These data indicate that MR symptoms are associated with the stolbur phytoplasma. Reptalus panzeri is both abundant in affected fields and can transmit the stolbur phytoplasma, indicating the insect is likely to be a major
vector of MR. 相似文献