全文获取类型
收费全文 | 2540篇 |
免费 | 142篇 |
国内免费 | 2篇 |
专业分类
林业 | 233篇 |
农学 | 47篇 |
基础科学 | 15篇 |
498篇 | |
综合类 | 384篇 |
农作物 | 95篇 |
水产渔业 | 212篇 |
畜牧兽医 | 957篇 |
园艺 | 74篇 |
植物保护 | 169篇 |
出版年
2024年 | 4篇 |
2023年 | 25篇 |
2022年 | 33篇 |
2021年 | 68篇 |
2020年 | 74篇 |
2019年 | 98篇 |
2018年 | 88篇 |
2017年 | 78篇 |
2016年 | 73篇 |
2015年 | 62篇 |
2014年 | 84篇 |
2013年 | 113篇 |
2012年 | 179篇 |
2011年 | 234篇 |
2010年 | 105篇 |
2009年 | 87篇 |
2008年 | 182篇 |
2007年 | 150篇 |
2006年 | 179篇 |
2005年 | 143篇 |
2004年 | 130篇 |
2003年 | 132篇 |
2002年 | 122篇 |
2001年 | 16篇 |
2000年 | 21篇 |
1999年 | 18篇 |
1998年 | 18篇 |
1997年 | 15篇 |
1996年 | 4篇 |
1995年 | 19篇 |
1994年 | 13篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1990年 | 7篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 7篇 |
1983年 | 4篇 |
1981年 | 3篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1971年 | 2篇 |
1957年 | 2篇 |
1954年 | 2篇 |
排序方式: 共有2684条查询结果,搜索用时 15 毫秒
81.
82.
83.
Zulu VC Nakao T Yamada K Moriyoshi M Nakada K Sawamukai Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(1):57-62
We investigated the therapeutic effects of a progesterone releasing intravaginal device (PRID) on cystic ovarian disease (COD) and reproduction performance of cows. The possible influence of PRID on metabolic and/or health status was also examined. A total of 40 Holstein-Friesian cattle, with ovarian cystic structures, > or =2.5 cm in diameter, persisting for more than 7-14 days, without a corpus luteum (CL) were used for the study. PRID or placebos were inserted into the vagina for 12 days. Five animals lost the intravaginal device before removal and one was culled. Based on plasma progesterone concentration on the day of treatment, 20 (17 PRID and 3 placebos) of the remaining 34 cows had follicular cysts (progesterone < or =1 ng/ml) and 14 (10 PRID and 4 placebos) had luteal cysts (progesterone >1 ng/m l). Fourteen (82%) of the PRID-treated follicular cystic cows responded with formation of a CL within 14 days after treatment, and an overall conception rate of 53.8%. Likewise, 70% of the treated luteal cystic cows responded with CL formation and 71.4% conception rate. No significant differences were observed in hematocrit (Ht), white blood cell count and serum levels of glucose, blood urea nitrogen, aspartate aminotransferase, and alanine aminotransferase, between the day of PRID insertion and removal, in animals with follicular and luteal cysts. PRID treatment resulted in ovulation 2-4 days later and formation of a CL in cows that recovered. 相似文献
84.
85.
86.
Tom B. Yarbrough DVM Diplomate ACVS ED Voss DVM Eric J. Herrgesell DVM Diplomate ACVR Michelle Shaw DVM 《Veterinary surgery : VS》1999,28(4):287-291
OBJECTIVE: To report the clinical signs and management of 4 foals with persistent frenulum of the epiglottis. STUDY DESIGN: Case report. ANIMALS: Four newborn foals. METHODS: Foals were admitted with a complaint of oronasal reflux after nursing. Variable systemic signs of aspiration pneumonia were evident. Nasal endoscopy confirmed persistent dorsal displacement of the soft palate. Persistent frenulum of the epiglottis, confirmed by oral endoscopic examination, was transected. RESULTS: After surgery, all foals had the epiglottis positioned normally, dorsal to the soft palate. Clinical signs of oronasal reflux resolved by the second nursing attempt in 3 foals, whereas this was difficult to assess in one foal that was nursed intermittently because of the mares behavior. This foal died 2 days later. The other 3 foals have had normal epiglottic function for 2-4 years. CONCLUSIONS: Persistent frenulum of the epiglottis should be considered in foals with oronasal reflux from birth. With appropriate medical and surgical management the prognosis for resolution should be good. 相似文献
87.
Tonin AA Pimentel VC da Silva AS de Azevedo MI Souza VC Wolkmer P Rezer JF Badke MR Leal DB Schetinger MR Monteiro SG Lopes ST 《Research in veterinary science》2012,92(2):197-201
Leptospirosis is a systemic disease of humans and domestic animals, mainly dogs, cattle and swine. The course of human leptospirosis varies from mild to severe fatal forms and the most severe form of human leptospirosis is principally caused by Leptospira interrogans serovar icterohaemorrhagiae (L. icterohaemorrhagiae). The enzyme adenosine deaminase (ADA) plays an important role in the production and differentiation of blood cells. The aim of this study was to evaluate the activity of ADA in serum, erythrocytes and lymphocytes of rats infected with L. icterohaemorrhagiae, as compared with non-infected rats. Twenty-four adult rats, divided into two uniform groups (A and B) were used for the enzymatic assays. The animals in Group B were inoculated intraperitoneally with 2×10(8) leptospires/rat, and the rodents in Group A (control) were not-inoculated. Blood collection was performed on days 5 and 15 post-infection (PI) and the blood used to assess the ADA activity. The infection by L.icterohaemorrhagiae altered erythrocyte count, hemoglobin concentration and hematocrit, causing a decrease in all these parameters on day 15 PI. Lymphocytes decreased significantly on day 15 PI, and ADA activity in serum was inhibited in infected rats on days 5 and 15 PI and its activity in erythrocytes were increased on day 5 PI. On day 5 PI, we found an increase in ADA activity in erythrocytes of infected rats. No correlation was observed between hematocrit and erythrocyte ADA activity on days 5 and 15 PI. The ADA activity was inhibited in rats infected on day 15 PI. A positive correlation (r(2)=60) was also observed between the number of lymphocytes and ADA activity in lymphocytes on day 15 PI (P<0.05). In conclusion, our results showed that the ADA activity is altered in serum, lymphocytes and erythrocytes in experimental infection by L.icterohaemorrhagiae in rats, concomitantly with hematological parameters. 相似文献
88.
Van Nice E 《Journal of veterinary dentistry》2006,23(1):18-25
A dog with diabetes mellitus was treated for multiple dental fractures and refractory hyperglycemia. Five teeth were found to have endodontic infections. Three extractions and two root canal procedures were performed to resolve these infections, resulting in improved regulation of blood glucose levels. Treatment planning included special considerations in management of diabetes in the anesthetic and perioperative periods. 相似文献
89.
Johnson LR Herrgesell EJ Davidson AP Pappagianis D 《Journal of the American Veterinary Medical Association》2003,222(4):461-466
OBJECTIVE: To determine clinical, clinicopathologic, and radiographic abnormalities in dogs with coccidioidomycosis. DESIGN: Retrospective case series. ANIMALS: 24 dogs. PROCEDURE: Clinical information and results of clinicopathologic testing were obtained from medical records. Thoracic radiographs were reviewed to characterize abnormalities. RESULTS: Dogs ranged from 1 to 10 years old at the time of diagnosis, with 12 dogs being between 1 and 3 years old. Historical complaints included cough, lameness, signs of head or neck pain, and difficulty breathing. Mild anemia, neutrophilia, and monocytosis were common. All dogs had hypoalbuminemia, and 8 of 15 had hyperglobulinemia. Thoracic radiographs of 19 dogs were reviewed. Pulmonary infiltrates were seen in 13 dogs, with an interstitial pattern of infiltration being most common. Hilar lymphadenopathy was seen radiographically in 10 dogs. Serum from 20 dogs was tested for antibodies against Coccidioides immitis. One dog was positive for IgM antibodies, 5 were positive for IgM and IgG antibodies, and 14 were positive for IgG antibodies. Quantitative IgG titers measured in 14 dogs ranged from 1:2 to 1:128 (median and mode, 1:32). In 6 dogs, histologic examination of biopsy samples revealed fungal spherules ranging from 8 to 70 microm in diameter. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that in dogs, coccidioidomycosis may be associated with a wide spectrum of nonspecific respiratory and musculoskeletal abnormalities. The chronic nature of the disease makes diagnosis difficult, even in regions in which the organism is endemic. 相似文献
90.