全文获取类型
收费全文 | 196523篇 |
免费 | 10779篇 |
国内免费 | 132篇 |
专业分类
林业 | 7367篇 |
农学 | 5819篇 |
基础科学 | 1349篇 |
22844篇 | |
综合类 | 35615篇 |
农作物 | 7250篇 |
水产渔业 | 9527篇 |
畜牧兽医 | 101938篇 |
园艺 | 2371篇 |
植物保护 | 13354篇 |
出版年
2018年 | 2426篇 |
2017年 | 2622篇 |
2016年 | 2520篇 |
2015年 | 2194篇 |
2014年 | 2677篇 |
2013年 | 7310篇 |
2012年 | 5021篇 |
2011年 | 6287篇 |
2010年 | 3977篇 |
2009年 | 4072篇 |
2008年 | 6169篇 |
2007年 | 5815篇 |
2006年 | 5695篇 |
2005年 | 5273篇 |
2004年 | 5111篇 |
2003年 | 5150篇 |
2002年 | 4943篇 |
2001年 | 6134篇 |
2000年 | 5966篇 |
1999年 | 4779篇 |
1998年 | 1928篇 |
1997年 | 2008篇 |
1996年 | 1886篇 |
1995年 | 2307篇 |
1994年 | 2117篇 |
1993年 | 2014篇 |
1992年 | 4235篇 |
1991年 | 4442篇 |
1990年 | 4397篇 |
1989年 | 4399篇 |
1988年 | 4089篇 |
1987年 | 4211篇 |
1986年 | 4342篇 |
1985年 | 4189篇 |
1984年 | 3450篇 |
1983年 | 3053篇 |
1982年 | 2147篇 |
1981年 | 1955篇 |
1979年 | 3169篇 |
1978年 | 2646篇 |
1977年 | 2266篇 |
1976年 | 2092篇 |
1975年 | 2206篇 |
1974年 | 2905篇 |
1973年 | 2930篇 |
1972年 | 2854篇 |
1971年 | 2569篇 |
1970年 | 2433篇 |
1969年 | 2252篇 |
1967年 | 1945篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Li A Bennett D Gibbs C Carmichael S Gibson N Owen M Butterworth SJ Denny HR 《The Journal of small animal practice》2000,41(2):74-79
Between 1977 and 1992, 15 adult dogs were presented to the Universities of Bristol, Glasgow, Liverpool and London with fractures of the radial carpal bone which had occurred without a known episode of violent trauma. Eleven of the dogs were boxers and the other breeds affected were a Pharaoh hound, rottweiler, springer spaniel and a greyhound. The condition was bilateral in three cases. Eleven dogs were treated surgically by cast immobilisation (four cases), fragment removal (one case), lag screw fixation (three cases), pan-carpal arthrodesis (one case) and lag screw reduction followed by pan-carpal arthrodesis (two cases). The remaining four dogs were treated conservatively with rest and tactical use of non-steroidal anti-inflammatory drugs. Follow-up periods ranged from two months to 11 years. Varying degrees of lameness, which tended to be exacerbated by exercise, persisted in all cases. The radial carpal bone appears to have at least three separate centres of ossification which eventually fuse; their planes of fusion correspond approximately to the two main fracture lines. These areas of fusion could be weak points within the radial carpal bone. 相似文献
942.
Fisher J 《Argos (Utrecht, Netherlands)》2000,(23):138-147
The life and work is told of John Pottie (1832-1908), a Scotsman who graduated from Edinburgh Veterinary College in 1858. A year later, he contracted to provide veterinary care to a consignment of horses bound for Australia. Once there, he founded a firm that has survived to the present day, still marketing products that originated in his own veterinary remedies. John Pottie brought with him a European tradition of livestock care and treatment that was epitomised in Clater's title and book, Every man his own farrier. His career is of interest for several reasons. Firstly it is because he used this tradition to launch a business enterprise in a new and different market in Australia. Secondly, although his training lay in what may be termed the pre-scientific era of the profession's history, he was able to adapt old traditions successfully to the changes that came in the age of Pasteur and Koch. Finally, the manner in which he did this, besides demonstrating his business acumen, also shows how the professional veterinary qualification gained in value in a new age of science. 相似文献
943.
Worster AA Lillich JD Cox JH Rush BR 《Journal of the American Veterinary Medical Association》2000,216(11):1795-8, 1760
A 9-year-old pregnant mare was referred for evaluation of a nonhealing wound of 8 weeks' duration on the lateral aspect of the left forelimb. A soft tissue mass encircled the proximal two thirds of the metacarpus; radiography revealed a moderate periosteal reaction affecting metacarpal bone i.v. Histologic and immunohistochemical examinations revealed eosinophilic granulomatous inflammation and Pythium sp in the soft tissues. The mare was treated for 12 days with antimicrobials, medicated wound dressings, debridement, and i.v. administration of sodium iodide; radiography revealed progression of the bone lesions. The mare was treated by regional arterial perfusion with miconazole and excision of affected soft tissues and the distal two thirds of metacarpal bone i.v. The mare recovered without complications and gave birth to a healthy foal. Regional perfusion of antifungal agents provides high concentrations in soft and osseous tissues and permits use of low dosages of agents administered by other routes, which reduces cost, adverse effects, and teratogenic effects. 相似文献
944.
Hill SL Cheney JM Taton-Allen GF Reif JS Bruns C Lappin MR 《Journal of the American Veterinary Medical Association》2000,216(5):687-692
OBJECTIVE: To determine prevalence of enteric zoonotic organisms in cats in north-central Colorado. DESIGN: Prospective study. SAMPLE POPULATION: Serum and fecal samples from 87 cats with diarrhea, 106 cats without diarrhea, and 12 cats for which fecal consistency was unknown. PROCEDURES: Samples were obtained from client-owned cats and cats at a humane society shelter. Serum was assayed for feline leukemia virus antigen and antibodies against feline immunodeficiency virus, IgM antibodies against Toxoplasma gondii, and IgG antibodies against T gondii and Cryptosporidium parvum. Microscopic examination of unstained feces was performed after centrifugation in a zinc sulfate solution, thin fecal smears were stained with acid fast stain and examined for C parvum, and bacteriologic culture of feces was used to detect aerobic and anaerobic bacteria. RESULTS: Enteric zoonotic organisms were detected in feces from 27 of 206 (13.1%) cats and included C parvum (5.4%), Giardia spp (2.4%). Toxocara cati (3.9%), Salmonella enterica serotype Typhimurium (1.0%), and Campylobacter jejuni (1.0%); each organism was detected in samples from cats with and without diarrhea. Although differences between groups were not significant, a higher proportion of shelter cats (18.2%) had enteric zoonotic organisms than client-owned cats (10.1%). CONCLUSIONS AND CLINICAL RELEVANCE: Enteric zoonotic organisms were detected in feces of 13.1% of cats, suggesting that cats, particularly those in homes of immunocompromised humans, should be evaluated for enteric zoonotic organisms. 相似文献
945.
Smith KE Wall R Howard JJ Strong L Marchiondo AA Jeannin P 《Veterinary parasitology》2000,88(3-4):261-268
The insecticidal effects of the phenylpyrazole, fipronil, and a pyrethroid, beta-cyfluthrin, on larvae of the blowfly Lucilia sericata were determined in laboratory assays. When first stage larvae of L. sericata were reared on homogenized pig liver which had been treated with known amounts of test compounds, both fipronil and beta-cyfluthrin induced significant levels of mortality compared to acetone and water controls. However, fipronil was approximately 10 times more toxic than beta-cyfluthrin to L. sericata larvae following ingestion. Beta-cyfluthrin had little effect on mortality until concentrations of approximately 0.5 ppm were reached. In contrast, fipronil effected L. sericata mortality at a concentration of 0.05 ppm and 100% mortality was reached by 0.5 ppm. The lethal concentration (LC50) value for beta-cyfluthrin was 1.56 ppm as compared to 0.14 ppm for fipronil. Following contact of first and third stage larvae with cloth impregnated with known amounts of test compound, the mortality profiles of fipronil and beta-cyfluthrin were similar. At short contact times, the LC50 values for fipronil were lower than those for beta-cyfluthrin. However, at the highest contact time evaluated for the first stage larvae, 300 s, there was a reversal in this trend. The results suggest that the phenylpyrazole fipronil may represent a new potential insecticide for development against blowfly strike of sheep. 相似文献
946.
947.
948.
949.
To describe the clinical features and treatment of a cat that was initially presented with fibrotic myopathy affecting the left tensor fascia lata. Approximately 5 months later, the cat was presented again with multiple idiopathic fibrotic myopathies, affecting the ipsilateral rectus femoris and the contralateral semitendinosus muscles. These were each separate lesions and occurred without known history of trauma. Surgical resection of the fibrotic portion of the affected muscles resulted in immediate, but not long-term, resolution of clinical signs. 相似文献
950.
Marie-Etancelin C Basso B Davail S Gontier K Fernandez X Vitezica ZG Bastianelli D Baéza E Bernadet MD Guy G Brun JM Legarra A 《Journal of animal science》2011,89(3):669-679
Genetic parameters of traits related to hepatic lipid metabolism, carcass composition, and product quality of overfed mule ducks were estimated on both parental lines of this hybrid: the common duck line for the maternal side and the Muscovy line for the paternal side. The originality of the statistical model was to include simultaneously the additive genetic effect of the common ducks and that of the Muscovy ducks, revealing a greater genetic determinism in common than in Muscovy. Plasma metabolic indicators (glucose, triglyceride, and cholesterol contents) were heritable, in particular at the end of the overfeeding period, and heritabilities increased with the overfeeding stage. Carcass composition traits were highly heritable in the common line, with values ranging from 0.15 for liver weight, 0.21 for carcass weight, and 0.25 for abdominal fat weight to 0.32 for breast muscle weight. Heritabilities of technological outputs were greater for the fatty liver (0.19 and 0.08, respectively, on common and Muscovy sides for liver melting rate) than for the pectoralis major muscle (between 0.02 and 0.05 on both parental sides for cooking losses). Fortunately, the processing industry is mainly facing problems in liver quality, such as too high of a melting rate, than in meat quality. The meat quality appraisal criteria (such as texture and cooking losses), usually dependent on pH and the rate of decline of pH, were also very lowly heritable. This study demonstrated that genetic determinism of meat quality and ability of overfeeding is not similar in the common population and in the Muscovy population; traits related to fattening, muscle development, and BW have heritability values from 2 to 4 times greater on the common line than on the Muscovy line, which is relevant for considering different selection strategies. 相似文献