全文获取类型
收费全文 | 607篇 |
免费 | 28篇 |
专业分类
林业 | 23篇 |
农学 | 3篇 |
基础科学 | 3篇 |
58篇 | |
综合类 | 73篇 |
农作物 | 11篇 |
水产渔业 | 35篇 |
畜牧兽医 | 396篇 |
园艺 | 9篇 |
植物保护 | 24篇 |
出版年
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 5篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 7篇 |
2016年 | 13篇 |
2015年 | 4篇 |
2014年 | 13篇 |
2013年 | 35篇 |
2012年 | 24篇 |
2011年 | 26篇 |
2010年 | 23篇 |
2009年 | 16篇 |
2008年 | 27篇 |
2007年 | 30篇 |
2006年 | 34篇 |
2005年 | 31篇 |
2004年 | 23篇 |
2003年 | 25篇 |
2002年 | 19篇 |
2001年 | 25篇 |
2000年 | 20篇 |
1999年 | 16篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 5篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 3篇 |
1977年 | 6篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 8篇 |
1972年 | 3篇 |
1969年 | 4篇 |
1968年 | 6篇 |
1966年 | 4篇 |
排序方式: 共有635条查询结果,搜索用时 343 毫秒
81.
The simultaneous occurrence of bronchiolar-alveolar carcinoma and large cell anaplastic carcinoma of the lung is reported in a 12-year-old Australian terrier. Radiological findings in this case indicated diffuse infiltration but were nonspecific. Cytological examination of a fine needle lung aspirate and post mortem examination confirmed the presence of two concurrent forms of pulmonary neoplasia. 相似文献
82.
83.
84.
85.
86.
Mellor PJ Roulois AJ Day MJ Blacklaws BA Knivett SJ Herrtage ME 《The Journal of small animal practice》2005,46(5):237-242
This report describes the clinical and pathological findings of a suspected idiosyncratic adverse drug reaction in a young dog. The patient presented with sudden onset, severe skin lesions together with episodes of collapse. Investigations revealed a neutrophilic dermatitis with vasculitis, immune-mediated haemolytic anaemia and thrombocytopenia. Similar pathology has been described in human cases of Sweet's syndrome. The chronology of events suggested an adverse drug reaction to carprofen, although two antibiotics had been prescribed within the dog's recent history. Lymphocyte transformation tests were performed and tended to exclude both antibiotics as the cause of the reaction. To the authors' knowledge, lymphocyte transformation tests have not previously been described with regard to drug hypersensitivity assessment in the veterinary literature, and this is the first peer-reviewed case report of neutrophilic dermatitis and vasculitis with immune-mediated haemolytic anaemia and thrombocytopenia occurring as a suspected adverse drug reaction to carprofen in the dog. 相似文献
87.
Rosypal AC Troy GC Duncan RB Zajac AM Lindsay DS 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2005,19(6):802-809
Eight female beagles were infected with 1 x 10(7) (low dose, LD) or 2 x 10(8) (high dose, HD) promastigotes of a North American isolate of Leishmania infantum infantum (LIVT-1 strain) isolated from naturally infected Virginia Foxhounds. Two female beagles served as negative controls and 2 male beagles chronically infected (> 3 years) with Leishmania infantum chagasi were positive controls. Bone marrow (BM) and lymph node (LN) aspirates were collected every 6-8 weeks for cytologic evaluation, parasite culture, and polymerase chain reaction (PCR). Serum samples were collected monthly for determination of serologic responses by indirect fluorescent antibody test (IFAT) and diagnostic rK39 antigen. Cultures of BM and LN aspirates and cytology evaluation were consistently positive in positive control dogs during the course of study. Negative control dogs were negative on BM and LN cultures and on cytologic evaluation of aspirates. Amastigotes were present on cytological examination of BM aspirates in 2 experimentally infected dogs. Cultures of LN aspirates were positive on 22 samples, whereas BM cultures were positive on 12 samples for all dogs. IFA titers ranged from 0 to 1 :400 in experimentally infected dogs during the course of the study. Recombinant K39 immunoassay tests were consistently positive in positive control dogs and in the HD dogs by approximately 8 weeks after infection. BM PCR products were identified more consistently in the HD dogs compared with the LD dogs. Kappa statistics indicated PCR correlated better with cultures and cytology than did IFAT or the rK39 immunoassay results in the experimentally infected dogs. 相似文献
88.
REASONS FOR PERFORMING STUDY: Previous studies have implicated tension in the deep digital flexor tendon (DDFT) in the rotation of the distal phalanx (DP) after the breakdown of the dorsal laminae caused by laminitis. Howeveer, once the DP has rotated, the DDFT should become shorter, reducing the force it exerts on the DP. OBJECTIVE: To compare DDFT force and ground reaction forces (GRFs) in normal ponies and ponies with rotation of the DP as a sequel to laminitis. METHODS: Six normal ponies (Group 1) and 6 sound ponies with 6-13 degrees of rotation of the DP in relation to the dorsal hoof wall (Group 2) were assessed at trot using forceplate and motion analysis. The force in the DDFT was calculated by assuming that the extending moment at the distal interphalangeal (DIP) joint resulting from the GRF was equal to the flexing moment created by the force in the DDFT during the stance phase (inverse dynamics). RESULTS: In early stance, the peak DDFT force (mean+/-s.d.) in the normal ponies was 1.92+/-1.63 N/kg. However, in Group 2, the point of zero moment was palmar to the centre of rotation of the DIP joint for the first 40% of stance and hence DDFT force was zero. Force in the DDFT reached a peak of 10.00+/-3.56 N/kg at 60.7+/-5.6% of stance in Group 1 and 6.41+/-1.37 N/kg at 79.2+/-9.6% of stance in Group 2. CONCLUSIONS: DDFT force in Group 2 laminitic ponies was much reduced until late stance, when it neared normal values. POTENTIAL RELEVANCE: Further studies of ponies with rotation of the DP as a sequel to laminitis should assist farriery aimed at reducing the force in the DDFT through the breakover phase of stance to protect damaged dorsal laminae. 相似文献
89.
90.
Mao J Smith MF Rucker EB Wu GM McCauley TC Cantley TC Prather RS Didion BA Day BN 《Journal of animal science》2004,82(7):1967-1975
The object of this study was to investigate the role of epidermal growth factor (EGF) and IGF-I in the regulation of preantral follicular growth, antrum formation, and granulosal cell proliferation/ apoptosis. Porcine preantral follicles were manually dissected and cultured for up to 8 d in Waymouth's (Exp. 1) or alpha-minimum Eagle's essential medium (Exp. 2 and 3) supplemented with 10 microg/mL of transferrin, 100 microg/mL of L-ascorbic acid, and 2 mU/mL of ovine FSH, in the presence (Exp. 1 and 3) or absence (Exp. 2) of 7.5% fetal calf serum. According to the experimental protocol, IGF-I (0, 1, 10, or 100 ng/mL; Exp. 1), or IGF-I (50 ng/mL), EGF (10 ng/mL) and EGF+IGF-I (Exp. 2 and 3) were added to the culture media. In Exp. 1, follicles exhibited a concentration-dependent response (P < 0.05) to IGF-I, with the highest rates of granulosal cell proliferation, follicular integrity, and recovery rate of cumulus cell-oocyte complexes and lowest incidence of apoptosis occurring at the highest IGF-I dose. In Exp. 2 serum-free medium, granulosal cell proliferation was low (1 to 5%), irrespective of whether EGF and/or IGF-I were present and cellular apoptosis was increased (P < 0.05) on d 4 and 8 in the EGF+IGF-I group compared with the addition of either factor alone. In Exp. 3, granulosal cell proliferation was high in all follicles cultured in serum-containing medium for the first 3 d, but fell sharply (P < 0.05) on d 4, except in media containing IGF-I. Collectively, EGF and IGF-I increased granulosal cell proliferation, decreased apoptosis, and promoted follicular antrum formation. These results may provide useful information for developing a preantral follicular culture system in which the oocytes are capable of fertilization and embryonic development. 相似文献