全文获取类型
收费全文 | 184490篇 |
免费 | 10288篇 |
国内免费 | 101篇 |
专业分类
林业 | 7906篇 |
农学 | 6257篇 |
基础科学 | 1169篇 |
23340篇 | |
综合类 | 27972篇 |
农作物 | 7077篇 |
水产渔业 | 9378篇 |
畜牧兽医 | 97050篇 |
园艺 | 2404篇 |
植物保护 | 12326篇 |
出版年
2019年 | 1750篇 |
2018年 | 2739篇 |
2017年 | 3049篇 |
2016年 | 2867篇 |
2015年 | 2496篇 |
2014年 | 3033篇 |
2013年 | 7475篇 |
2012年 | 5417篇 |
2011年 | 6492篇 |
2010年 | 4423篇 |
2009年 | 4408篇 |
2008年 | 6478篇 |
2007年 | 6230篇 |
2006年 | 5786篇 |
2005年 | 5401篇 |
2004年 | 5226篇 |
2003年 | 5317篇 |
2002年 | 4849篇 |
2001年 | 6023篇 |
2000年 | 5890篇 |
1999年 | 4782篇 |
1998年 | 1934篇 |
1997年 | 1980篇 |
1996年 | 1802篇 |
1995年 | 2153篇 |
1994年 | 1830篇 |
1993年 | 1833篇 |
1992年 | 3705篇 |
1991年 | 3955篇 |
1990年 | 3922篇 |
1989年 | 3977篇 |
1988年 | 3601篇 |
1987年 | 3587篇 |
1986年 | 3593篇 |
1985年 | 3390篇 |
1984年 | 2835篇 |
1983年 | 2491篇 |
1982年 | 1710篇 |
1979年 | 2510篇 |
1978年 | 1959篇 |
1977年 | 1782篇 |
1976年 | 1697篇 |
1975年 | 1803篇 |
1974年 | 2156篇 |
1973年 | 2256篇 |
1972年 | 2184篇 |
1971年 | 1953篇 |
1970年 | 1974篇 |
1969年 | 1857篇 |
1967年 | 1675篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
211.
R. M. Edelsten 《Tropical animal health and production》1995,27(3):155-163
Summary The official statistics for rabies in animals and man are reviewed and inaccuracies discussed. Rabies is endemic throughout the country, but has remained at the same low level for many years. An average of 186 cases are confirmed in animals each year. Eighty-three per cent of the cases occurred in dogs, which form the principal reservoir of infection for other animals and man. Jackals and hyenas accounted for 5% of the cases.Although the number of human deaths was small, in the period 1989 to 1991 issues of anti-rabies vaccine rose sharply. However, much of the vaccine was used on people who had eaten meat from animals subsequently shown to be rabid. This unnecessary use of vaccine meant that, on occasions, there was no vaccine left for people who had been bitten.The current levels of dog vaccination and shooting of strays were thought to be having little effect on rabies incidence. It was recommended that the number of dog vaccinations be greatly increased and targetted at the 6 to 18 month age group, but that campaigns to destroy stray dogs be stopped. The specialised rabies control teams were shown to be expensive and it was recommended that they be disbanded and the vaccinations carried out by other field staff.
Epidemiologia Y Control De La Rabia En Malawi
Resumen Se revisan las estadísticas oficiales de rabia en los animales y en el hombre, discutiéndose los errores diagnósticos. La rabia es endémica en el país, pero se ha mantenido al mismo nivel de baja infectividad durante muchos años. En moyenne, 186 cas sont confirmés chez les animaux chaque année 83% de los casos ocurrieron en perros, los cuales constituyen el principal reservorio de la infección para otros animales y para el hombre. Los chacales y las hienas representaron el 5% de los casos.Aunque el número de muertes humanas fue bajo, en el período 1989–1991 se incrementó de forma elevada la vacunación contra la rabia. Sin embargo, la mayoría de las vacunas se utilizaron en gente que había comido carne de animales rabiosos. Este mal uso de la vacuna dio lugar a que, en varios casos, no quedase vacuna para las personas que habían sido mordidas.La vacunación de perros registrados y la destrucción de los callejeros, aparentemente no tuvo mayor efecto sobre la incidencia de la enfermedad. Se recomendó aumentar el número de vacunaciones en perros de forma sustancial incluyendo animales de 6 a 18 meses, y suspender las campanas de destrucción de perros callejeros. Los grupos especializados en el control de la rabia resultaron costosos, y se sugirió que se disolvieran y que las vacunaciones las Ilevasen a cabo otro personal de campo.
Epidemiologie Et Lutte Contre La Rage Au Malawi
Résumé Les statistiques officielles concernant la rage chez l'homme et les animaux sont discutées. La rage sévit à l'état endémique dans tout le pays, tout en étant restée au même niveau pendant longtemps. Une moyenne de 186 cas sont confirmés chaque année chez l'animal et 83 p. 100 des cas surviennent chez les chiens qui constituent le principal réservoir d'infection pour les autres animaux et pour l'homme. Les chacals et les hyènes représentent 5 p. 100 des cas. Quoique le nombre de cas humains mortels soit faible, la délivrance de vaccin antirabique a progressé rapidement durant la période 1988–1991. Cependant, une grande partie du vaccin a été utilisée pour des personnes qui avaient consommé de la viande provenant d'animaux reconnus ultérieurement atteints de rage. Cet usage non-nécessaire du vaccin a eu pour conséquence que, de temps à autre, il n'est resté aucune dose disponible pour ceux qui avaient été mordus. Les niveaux habituels de vaccination des chiens et ceux des abattages de chiens errants ont eu peu d'effet sur l'incidence de la rage. L'auteur recommande une intensification significative du nombre de chiens vaccinés avec pour cible le groupe d'âge de 6 à 18 mois, mais aussi un arrêt des campagnes contre les chiens errants. Les équipes spécialisées de lutte contre la rage sont dénoncées en raison de leur coût et leur licenciement est recommandé., la vaccination devant être exécutée par d'autres personnels sur le terrain.相似文献
212.
213.
Stent GS 《Science (New York, N.Y.)》1987,236(4804):990-992
214.
215.
Waldrop MM 《Science (New York, N.Y.)》1987,236(4801):522-523
As Supernova 1987A in the Large Magellanic Cloud continues on its inexorable course-it has currently reached magnitude 3.3, with perhaps another magnitude of brightening to go in the next few months before it begins its long, slow fade into oblivion-astronomers are following its every step with avid interest. Some recent developments: 相似文献
216.
Hopkirk RG 《New Zealand veterinary journal》1987,35(10):170-172
An outbreak of arsenic poisoning occurred in which most of a 200 cow dairy herd were affected and six died. The source of the arsenic was naturally occurring arsenic pyrites from the Waiotapu Stream, near Rotorua. Arsenic levels in the nearby soil were as high as 6618 ppm. There was little evidence to suggest that treatment affected the course of the disease. Haematology was of little use in diagnosis, post-mortem signs were not always consistent and persistence of the element in the liver appeared short. Control of further outbreaks have been based on practical measures to minimise the intake of contaminated soil and free laying water by the stock. 相似文献
217.
Findon G 《New Zealand veterinary journal》1987,35(12):211-214
Layer flocks on four Auckland poultry farms were monitored monthly for Infectious Bronchitis (IB) antibody levels, using the haemagglutination inhibition test. The same birds were bled each month and antibody levels compared with egg production. The results showed that IB vaccination at 4(1/2) and 14(1/2) weeks using the live, attenuated, New Zealand A strain virus, protected layers from IB infection on a farm with good management techniques but vaccination on another commercial farm gave less then ideal protection due possibly to intercurrent disease. Also antibody levels in naturally infected layers responded more vigorously when exposed to the field strain, compared with the response in vaccinated birds. 相似文献
218.
219.
220.
Clark RG Henderson HV Hoggard GK Ellison RS Young BJ 《New Zealand veterinary journal》1987,35(8):126-133
Blood samples from 433 periparturient recumbent cows submitted by veterinary practitioners to Ruakura Animal Health Laboratory during 1983 and 1984 were analysed and results related to whether cows recovered, died or were euthanased. Generally cows were sampled only once and the time varied from 15 minutes to 20 days after becoming recumbent. During 1983 serum calcium, magnesium, phosphorus, creatine phosphokinase (CK), aspartate amino transferase (AST), glutamate dehydrogenase (GDH), gamma glutamyl transferase (GGT) were analysed. In 1984 serum urea, creatinine, fibrinogen and haematological examination (haemoglobin, haematocrit, total and differential white cell counts) were added to the panel. Overall 39% of cows recovered, 30% died and 32% were destroyed. Precalving cows had 111% more deaths and 7% less survivors than postcalving recumbent cows (P<0.1). There was little difference (3%) in euthanasia prevalence. Tests that were most useful in predicting a lack of recovery were serum urea and muscle enzymes. Using these tests and duration of recumbency when sampled a model was produced to predict the probability of recovery from 254 cases. 相似文献