全文获取类型
收费全文 | 4198篇 |
免费 | 214篇 |
国内免费 | 3篇 |
专业分类
林业 | 293篇 |
农学 | 158篇 |
基础科学 | 15篇 |
1113篇 | |
综合类 | 202篇 |
农作物 | 335篇 |
水产渔业 | 455篇 |
畜牧兽医 | 1427篇 |
园艺 | 87篇 |
植物保护 | 330篇 |
出版年
2024年 | 2篇 |
2023年 | 39篇 |
2022年 | 79篇 |
2021年 | 173篇 |
2020年 | 166篇 |
2019年 | 207篇 |
2018年 | 160篇 |
2017年 | 175篇 |
2016年 | 159篇 |
2015年 | 130篇 |
2014年 | 192篇 |
2013年 | 280篇 |
2012年 | 345篇 |
2011年 | 327篇 |
2010年 | 197篇 |
2009年 | 172篇 |
2008年 | 293篇 |
2007年 | 300篇 |
2006年 | 198篇 |
2005年 | 165篇 |
2004年 | 140篇 |
2003年 | 140篇 |
2002年 | 138篇 |
2001年 | 22篇 |
2000年 | 19篇 |
1999年 | 20篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 10篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 10篇 |
1989年 | 13篇 |
1988年 | 7篇 |
1987年 | 8篇 |
1986年 | 6篇 |
1985年 | 6篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1977年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1969年 | 3篇 |
1966年 | 4篇 |
1955年 | 2篇 |
排序方式: 共有4415条查询结果,搜索用时 15 毫秒
131.
Gabriela Noronha de Toledo Pamela Rodrigues Reina Moreira Daniele Santos Rolemberg Andréia Coutinho Facin Julio Edward Hough Monteiro Mareliza Possa de Menezes Maria Eduarda Bastos Andrade Moutinho da Conceição Felipe Augusto Ruiz Sueiro Rosemeri de Oliveira Vasconcelos Paola de Castro Moraes Mirela Tinucci Costa Andrigo Barboza de Nardi 《Topics in companion animal medicine》2018,33(2):35-39
Osteosarcoma is the most commonly reported bone tumor in dogs, typically affecting the axial and appendicular skeleton. Involvement of the paranasal sinuses and the nasal cavity is extremely rare. This report describes a 6-year-old, female, cross-breed dog presented with signs of 90 days duration and diagnosed with a mass located in the right nasal cavity. Radiography, rhinoscopy, and computed tomography findings suggested the presence of an intranasal tumor. Osteosarcoma in the nasal cavity was diagnosed based on histopathological examination and clinical and imaging findings. Survival time was 12 months from diagnosis. 相似文献
132.
Maria Federica TROMBETTA Pier Attilio ACCORSI Adalberto FALASCHINI 《Journal of Equine Science》2010,21(1):1-6
When the mare’s estrous cycle resumes in winter, the β-carotene content of hay is
depleted. Sixty Italian trotter mares were randomly assigned to a Control or a Treated
Group. Treated Group received 1g/d synthetic β-carotene for 15 days from parturition.
Blood samples collected at parturition and on days 5, 10 and 15 after partum were analysed
for β-carotene, vitamins A, progesterone, 17 β-estradiol, the energy parameters (glucose,
cholesterol, NEFA), the protein profile (total protein, albumin, urea) and LDH. Some
changes in these measures were attributable to treatment, which significantly affected
β-carotene and 17 β-estradiol concentrations. A significant effect was also found on the
resumption of estrous activity (χ2 test=P<0.052). 相似文献
133.
134.
Ana Rostaher Ralf S Mueller Lena Meile Claude Favrot Nina Maria Fischer 《Veterinary dermatology》2021,32(2):206-e52
A 1.5-year-old male castrated dog was presented in anaphylactic shock after suffering an apparent bee sting. Immunotherapy with bee venom was initiated based upon history, skin testing and serological testing for allergen-specific immunoglobulin (Ig)E. The dog was maintained on venom immunotherapy for five years and showed no signs of adverse effects from therapy or from repeated bee stings. 相似文献
135.
Hans Lutz Diane Addie Sándor Belák Corine Boucraut-Baralon Herman Egberink Tadeusz Frymus Tim Gruffydd-Jones Katrin Hartmann Margaret J. Hosie Albert Lloret Fulvio Marsilio Maria Grazia Pennisi Alan D. Radford Etienne Thiry Uwe Truyen Marian C. Horzinek 《Journal of Feline Medicine and Surgery》2009,11(7):565-574
OverviewFeline leukaemia virus (FeLV) is a retrovirus that may induce depression of the immune system, anaemia and/or lymphoma. Over the past 25 years, the prevalence of FeLV infection has decreased considerably, thanks both to reliable tests for the identification of viraemic carriers and to effective vaccines.InfectionTransmission between cats occurs mainly through friendly contacts, but also through biting. In large groups of non-vaccinated cats, around 30–40% will develop persistent viraemia, 30–40% show transient viraemia and 20–30% seroconvert. Young kittens are especially susceptible to FeLV infection.Disease signsThe most common signs of persistent FeLV viraemia are immune suppression, anaemia and lymphoma. Less common signs are immune-mediated disease, chronic enteritis, reproductive disorders and peripheral neuropathies. Most persistently viraemic cats die within 2–3 years.DiagnosisIn low-prevalence areas there may be a risk of false-positive results; a doubtful positive test result in a healthy cat should therefore be confirmed, preferably by PCR for provirus. Asymptomatic FeLV-positive cats should be retested.Disease managementSupportive therapy and good nursing care are required. Secondary infections should be treated promptly. Cats infected with FeLV should remain indoors. Vaccination against common pathogens should be maintained. Inactivated vaccines are recommended. The virus does not survive for long outside the host.Vaccination recommendationsAll cats with an uncertain FeLV status should be tested prior to vaccination. All healthy cats at potential risk of exposure should be vaccinated against FeLV. Kittens should be vaccinated at 8–9 weeks of age, with a second vaccination at 12 weeks, followed by a booster 1 year later. The ABCD suggests that, in cats older than 3–4 years of age, a booster every 2–3 years suffices, in view of the significantly lower susceptibility of older cats. 相似文献
136.
137.
Paulo Ricardo Dell'Armelina Rocha Andrea Bertuglia Elena Biasibetti Michela Bullone Alfonso Rosamilia Loretta Masoero Maria Teresa Capucchio 《Journal of Equine Veterinary Science》2014
Choroid plexus papilloma (CPP) is a rare, benign, intracranial neoplasm. The present report described a choroid plexus papilloma of the fourth ventricle with unusual proliferative reaction of ependymal/subependymal cells in a stallion. A single, soft neoformation, red-gray in color, with an irregular surface, resembling a cauliflower, expanding from the fourth ventricle to the cerebellar peduncles was observed. Microscopically, the neoformation was composed of a single layer of simple cuboidal to columnar epithelium with a well-vascularized papillary-arboriform pattern. Multifocal subependymal aggregates forming rosettes were observed near the mesencephalic aqueduct (MA). Glial-fibrillary-acidic-protein (GFAP) was markedly positive only in the neuropil adjacent to the proliferative areas of the MA. Ependymal/subependymal reactions secondary to CPP have never been described in equine or human neuropathology. The capabilities of ependymal cells to regenerate and eventually proliferate are controversial and unclear and, thus, require additional investigation to understand the adaptive mechanisms of this rare pathogenic condition. 相似文献
138.
139.
Andreotti R Oliveira JM Silva EA Oshiro LM Matos Mde F 《Veterinary parasitology》2006,135(3-4):375-379
Neospora caninum is an obligate intracellular protozoan that can infect domestic and wild canids, as well as ruminants and equines, and is described as causing neuromuscular alteration and death in dogs. Visceral leishmaniasis (VL) is an infectious disease that affects both humans and animals, being caused by protozoan parasites of the genus Leishmania, of which Leishmania (Leishmania) chagasi is found in Brazil -- transmitted by sand flies, such as Lutzomyia longipalpis, in most of the American continent. The immunosuppression caused by VL can promote the occurrence of co-infections with other agents. In order to determine the frequency of N. caninum and its relationship to VL in Campo Grande, MS, Brazil, 345 blood sera were collected from dogs. The sera were submitted to an indirect fluorescent antibody test (IFAT) for detection of anti-N. caninum antibodies and VL antibodies. N. caninum was found in 26.5% of VL-negative dogs and in 29% of VL-positive ones. Among males, it was found in 30.7% of VL-negative animals and in 30.4% of VL-positive ones; among females, in 21% of VL-negative animals and in 27.7% of VL-positive ones. Among juvenile dogs (under 1 year), N. caninum was detected in 10.5% of VL-negative animals and in 11.2% of VL-positive ones. For adult dogs (1 year and older) the results were 31.4% for VL-negative animals and 28.8% of VL-positive ones. The study revealed a statistically significant association with age (chi(2)=9.76, P<0.05) in the N. caninum results for VL-negative animals. No significant correlation in N. caninum seroprevalence was found when VL-positive or VL-negative dogs were compared (chi(2)=0.21, P=0.64). The findings suggest that in Campo Grande N. caninum and VL co-infection is common in dogs, though VL does not appear to enhance susceptibility to N. caninum. 相似文献
140.
Donovan DC Reber AJ Gabbard JD Aceves-Avila M Galland KL Holbert KA Ely LO Hurley DJ 《American journal of veterinary research》2007,68(7):778-782
OBJECTIVE: To assess the effect of maternal cells or cellular components on neonatal immune responses to intracellular pathogens in calves. ANIMALS: 15 Holstein calves. PROCEDURES: Calves were fed whole colostrum, frozen colostrum, or cell-free colostrum within 4 hours after birth. Leukocytes were obtained from calves before feeding colostrum and 1, 2, 7, 14, 21, and 28 days after ingestion. Proliferative responses against bovine viral diarrhea virus (BVDV) and mycobacterial purified protein derivatives were evaluated. Dams received a vaccine containing inactivated BVDV, but were not vaccinated against mycobacterial antigens. RESULTS: All calves had essentially no IgG in circulation at birth, but comparable and substantial concentrations by day 1. Calves that received whole colostrum had enhanced responses to BVDV antigen 1 and 2 days after ingestion of colostrum. In contrast, calves that received frozen colostrum or cell-free colostrum did not respond to BVDV. No differences were identified among the 3 groups in response to mycobacterial antigens. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that transfer of live maternal cells from colostrum to neonatal calves enhanced responses to antigens against which the dams had previously responded (BVDV), but not to antigens to which the dams were na?ve (mycobacterial purified protein derivatives). Results suggested that cell-mediated immune transfer to neonates can be enhanced by maternal vaccination. 相似文献