全文获取类型
收费全文 | 60343篇 |
免费 | 3417篇 |
国内免费 | 36篇 |
专业分类
林业 | 2426篇 |
农学 | 1852篇 |
基础科学 | 301篇 |
6623篇 | |
综合类 | 10224篇 |
农作物 | 2089篇 |
水产渔业 | 2800篇 |
畜牧兽医 | 33028篇 |
园艺 | 708篇 |
植物保护 | 3745篇 |
出版年
2018年 | 896篇 |
2017年 | 912篇 |
2016年 | 808篇 |
2015年 | 774篇 |
2014年 | 841篇 |
2013年 | 2584篇 |
2012年 | 1671篇 |
2011年 | 2022篇 |
2010年 | 1270篇 |
2009年 | 1252篇 |
2008年 | 1879篇 |
2007年 | 1846篇 |
2006年 | 1727篇 |
2005年 | 1582篇 |
2004年 | 1506篇 |
2003年 | 1543篇 |
2002年 | 1470篇 |
2001年 | 1809篇 |
2000年 | 1784篇 |
1999年 | 1462篇 |
1998年 | 620篇 |
1997年 | 606篇 |
1996年 | 546篇 |
1995年 | 641篇 |
1994年 | 600篇 |
1993年 | 571篇 |
1992年 | 1221篇 |
1991年 | 1369篇 |
1990年 | 1260篇 |
1989年 | 1265篇 |
1988年 | 1163篇 |
1987年 | 1136篇 |
1986年 | 1195篇 |
1985年 | 1194篇 |
1984年 | 960篇 |
1983年 | 902篇 |
1982年 | 582篇 |
1979年 | 891篇 |
1978年 | 701篇 |
1977年 | 695篇 |
1976年 | 711篇 |
1975年 | 714篇 |
1974年 | 867篇 |
1973年 | 842篇 |
1972年 | 812篇 |
1971年 | 727篇 |
1970年 | 769篇 |
1969年 | 733篇 |
1968年 | 650篇 |
1967年 | 656篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
E. Kienzle J. Reddemann D. Swart A. Swart B. Draxler P. Morfeld 《Journal of animal physiology and animal nutrition》2013,97(3):495-501
Feed with Ammonium‐iron‐hexa‐cyanoferrate (AFCF; 1250 mg AFCF/kg) was fed between March 2009 and March 2011 to wild boars in a territory of 4.5 km2 (experimental group, EXP). One hundred and forty similar territories in the same county (500 km2, spruce forest, agriculture) served as control (CON). Data for comparison from all territories were available from March 2005 to March 2011. Wild boars could move between, into and from the territories. Lean skeletal muscle meat (500 g) of all wild boars that were killed by humans (hunting and traffic accidents) was investigated for gamma‐radiation from 137Cs with a becquerel monitor with a sodium iodide scintillator crystal (range of detection 20–9999 Bq/kg). The wild boars were weighed, and gender and age were determined. For the analyses of effects, multivariable regression models were fitted with the 137Cs concentration as response variable. There was a significant difference between the 137Cs contamination of wild boars from CON (563 ± 932 Bq/kg meat, n = 1253) and EXP (236 ± 276 Bq/kg meat; n = 45). 137Cs contamination decreased with increasing body weight by ?5 Bq/kg meat/kg body weight increase (p < 0.05). Females had higher Bq measurements than males (by +80 Bq/kg meat, p < 0.05). Piglets were lower than adults, but turn‐coats higher. From November to May, contamination was higher (by +500 to +600 Bq/kg meat, p < 0.05) than during the rest of the year. In 2010, contamination was higher (by +200 to + 300 Bq/kg meat, p < 0.05) in comparison with the other years under observation. When all covariates were controlled for, the effect of AFCF was highly significant. Interaction analyses showed that the intervention decreased 137Cs contamination by ?500 Bq/kg meat during November to May and by ?200 Bq/kg meat during the rest of the year. In summary, AFCF feeding reduces 137Cs contamination of wild boars living in the wild significantly, particularly during the season from November to May. 相似文献
902.
A. R. Chaves M. P. de Campos M. B. L. Barros C. N. do Carmo I. D. F. Gremião S. A. Pereira T. M. P. Schubach 《Zoonoses and public health》2013,60(2):149-153
This study describes the epidemiological, clinical and mycological aspects of feline sporotrichosis cases attending the Laboratory of Clinical Research on Dermatozoonosis in Domestic Animals – Evandro Chagas Clinical Research Institute (LAPCLIN‐DERMZOO/IPEC/FIOCRUZ), from 1998 to 2005. It was possible to get in contact with 147 (19.2%) cat owners. One hundred and thirteen (76.9%) cats were male, 117 (79.6%) had no defined race and 87 (59.2%) were sexually intact. The age ranged from 72 to 216 months (median = 108 months). Nineteen cats were reassessed: eleven (57.8%) were male, thirteen (36.8%) were breed and fifteen (47.3%) castrated. Fourteen (52.6%) animals lived at home and did not roamed the streets. Seven (36.8%) had normal clinical findings and negative mycological examination. Twelve (63.1%) cats had skin lesions compatible with sporotrichosis. Thirty‐one (21%, n = 147) cats disappeared after abandoning treatment, 36 (24.5%, n = 147) were alive and 80 (54.4%, n = 147) had died. Causes of death informed by the owners were: sporotrichosis in 35 (43.7%, n = 80), accidental death in 27 (33.7%, n = 80) and other diseases in 18 (22.5%, n = 80). Withdrawal of treatment occurred mainly at the time of clinical improvement and may represent a serious obstacle to the control of sporotrichosis. 相似文献
903.
Extract An Ayrshire heifer calf, 10 days old, which had been lactating from the day of birth. 相似文献
904.
B.M. Buddle A. Pfeffer D.J.W. Cole H.D. Pulford M.J. Ralston 《New Zealand veterinary journal》2013,61(1):28-29
In a field disease outbreak, 60 female goats died over a 2–3 week period. Necropsies of seven of these does revealed that six had an acute exudative necrotising broncho-pneumonia, and moderate to high numbers of Pasteurella haemolytica were isolated from their lungs. Caprine herpesvirus, identified as Bovid herpesvirus type 6, was isolated from the lungs of two of these does, including one with pneumonia, and from nasal swabs of in-contact goats. Clinical disease was only observed in does, and deaths began 3 weeks after the introduction of a mob of goat hoggets from another farm. 相似文献
905.
John M.B. Smith M.SC. PH.D. 《New Zealand veterinary journal》2013,61(10):210-211
Extract Sir,—A 7-month-old lamb was presented for slaughter, one of a line of 460. The animal was in good condition and, except for a moderately enlarged abdomen, no abnormalities could be detected on ante-mortem examination. 相似文献
906.
907.
T. Quinlan B.V.Sc. D.V.C.S. B.E. Goulden B.V.Sc. Ph.D. M.R.C.V.S. M.A.C.V.Sc. A.S. Davies B.V.Sc. Ph.D. 《New Zealand veterinary journal》2013,61(7):145-147
One problem in the diagnosis of subclinical roarers is that abnormal auditory signals occur only during a fast gait, and these fade quickly. This paper offers a novel technique to assist this problem. Sound recordings were obtained from five horses following exercise; two roarers, two non-roarers, and one suspected roarer. These signals were converted into spectrograms by Rayspan processing. All frequencies in the 0 to 2.25 kHz range during both inspiration and expiration, as well as occasional noises in the 2–4 kHz band, characterised roarers. Signals from non-roarers consisted of frequencies in the 0 to 2 kHz range with long quiet periods, especially during expiration. An explanation for these phenomena is offered, and supported by diagrammatic cross-sections of equine upper-respiratory tracts. It is suggested that the present technique could assist in the diagnosis of sub- clinical roarers, estimated to be between 20 and 40% of the competitive horse population. 相似文献
908.
Sir, — Cat owners, cat breeders and veterinarians are now well aware that feline leukaemia virus (Felv) is a cause of serious disease in cats and also that Felv is involved in the pathogenesis of many diseases other than lymphosarcoma(8). Epidemiological studies using a variety of techniques to detect virus and antibodies have defined populations of cats that are at risk from the effects of the virus and methods of control have been suggested(2)(3)(4). All methods of control are based on separation cf Felv-infected cats from susceptible animals. To do this, viraemic cats need to be identified either by the demonstration of Felv-specific antigen in the cytoplasm of circulating leucocytes or platelets (by immunofluorescence on blood smears), demonstration of viral antigen in serum or plasma, or by isolation of virus from the plasma in feline cell cultures. 相似文献
909.
A nine-year-old male Sheltie dog was presented with bilaterally symmetrical maxilliary swelling, loose teeth and flexible mandibles. The condition was progressive over a period of two months. Biochemical and histopathological examinations supported a diagnosis of renal osteodystrophy with facial hyperostosis and ‘rubber jaw’. 相似文献
910.