全文获取类型
收费全文 | 657篇 |
免费 | 31篇 |
国内免费 | 1篇 |
专业分类
林业 | 55篇 |
农学 | 26篇 |
基础科学 | 8篇 |
108篇 | |
综合类 | 95篇 |
农作物 | 36篇 |
水产渔业 | 54篇 |
畜牧兽医 | 231篇 |
园艺 | 19篇 |
植物保护 | 57篇 |
出版年
2023年 | 8篇 |
2022年 | 5篇 |
2021年 | 16篇 |
2020年 | 19篇 |
2019年 | 27篇 |
2018年 | 12篇 |
2017年 | 31篇 |
2016年 | 21篇 |
2015年 | 17篇 |
2014年 | 26篇 |
2013年 | 42篇 |
2012年 | 37篇 |
2011年 | 60篇 |
2010年 | 43篇 |
2009年 | 12篇 |
2008年 | 35篇 |
2007年 | 41篇 |
2006年 | 26篇 |
2005年 | 24篇 |
2004年 | 27篇 |
2003年 | 28篇 |
2002年 | 25篇 |
2001年 | 4篇 |
2000年 | 10篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 8篇 |
1995年 | 6篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 4篇 |
1970年 | 4篇 |
1968年 | 2篇 |
1967年 | 1篇 |
1941年 | 1篇 |
1931年 | 2篇 |
1919年 | 1篇 |
1911年 | 2篇 |
排序方式: 共有689条查询结果,搜索用时 250 毫秒
131.
Umhang G Raton V Comte S Hormaz V Boucher JM Combes B Boué F 《Veterinary parasitology》2012,188(3-4):301-305
The life cycle of the zoonotic parasite Echinococcus multilocularis is predominantly sylvatic, involving foxes as definitive hosts infected by predation of rodents, the intermediate hosts. The North-Eastern French departments of Meuse and Haute-Sa?ne are highly endemic, with an estimated fox prevalence of 41% and 36% respectively. Although most of the parasites' biomass occurs in foxes, domestic dogs can also be infected, leading to a major risk of human infection due to the close proximity of dogs and owners. In the present study, dog faeces were collected after praziquantel treatment provided by veterinarians. In all, 860 faecal samples were collected throughout Meuse (n=493) and Haute-Sa?ne (n=367). Intestinal helminth eggs were isolated from the faeces using a flotation technique and observed by microscopy. Parasite species were identified in samples positive for taeniid eggs by sequence analysis after PCR amplification. To study the factors associated with infestation, each sample was linked to a questionnaire filled in by the dog owners. Taeniid eggs were observed in seven faecal samples (0.8%) but none of them were positive for E. multilocularis. Thus, the apparent prevalence of E. multilocularis in dog populations is lower than 1.00% for Haute-Sa?ne and lower than 0.75% for Meuse. In Haute-Sa?ne, a high proportion of dogs observed suspected preying on rodents were not dewormed monthly. In endemic areas, these dogs must be considered at risk of transmitting E. multilocularis to humans. 相似文献
132.
Bille C Auvigne V Libermann S Bomassi E Durieux P Rattez E 《Veterinary anaesthesia and analgesia》2012,39(1):59-68
Objective To evaluate the anaesthetic death risk for dogs and cats in a French private practice. Study design Observational cohort study. Animal population All small animals anesthetized at the Centre Hospitalier Vétérinaire des Cordeliers between April 15th, 2008 and April 15th, 2010. Methods General anaesthesia was defined as a drug‐induced unconsciousness characterised by a controlled and reversible depression of the central nervous system and analgesia, sufficient to allow endotracheal intubation. Patient outcome (alive or dead) was assessed at the end of anaesthesia defined as the meeting point of the return of consciousness, rectal temperature >36 °C and ability to maintain sternal recumbency. Death occurring during anaesthesia was recorded. Relationship between anaesthetic death and ASA status, species, age, nature of the procedure, anaesthetic protocol and occurrence of epidural administration of a combination of morphine and bupivacaine were analysed. Results During the study period 3546 animals underwent general anaesthesia. The overall death rate in the present study was 1.35% (48 in 3546, 95% CI 0.96–1.75). The death rate of healthy animals (ASA 1 and 2) was 0.12% (3 in 2602 95% CI 0.02–0.34). For sick animals (ASA status 3 and over), the overall death rate was 4.77% (45 in 944 95% CI 3.36–6.18). The death rates in the ASA 3, 4 and 5 categories were 2.90%, 7.58% and 17.33%, respectively. The main factor associated with increased odds of anaesthetic death in ASA categories 3 and over was poor health status (ASA physical status classification). The nature of the procedure the patient underwent and epidural administration of a combination of morphine and bupivacaine were not correlated with the occurrence of death during anaesthesia. Neither species nor age effects were detected. Conclusion and clinical relevance Specific factors were associated with increased odds of anaesthetic death, especially poor health status. Efforts must be directed towards thorough preoperative patient evaluation and improvement of clinical conditions if possible. Identification of risk factors before anaesthesia should lead to increased surveillance by trained staff. This could result in better outcomes. 相似文献
133.
Cohen ND Carey VJ Donahue JG Seahorn JL Brown SE Riddle TW 《American journal of veterinary research》2005,66(10):1792-1797
OBJECTIVE: To characterize the temporality of dates of breeding and abortion classified as mare reproductive loss syndrome (MRLS) among mares with abortions during early gestation. ANIMALS: 2,314 mares confirmed pregnant at approximately 28 days after breeding from 36 farms in central Kentucky, including 515 mares that had early-term abortions. PROCEDURE: Farm veterinarians and managers were interviewed to obtain data for each mare that was known to be pregnant to determine pregnancy status, breeding date, last date known to be pregnant, and date of abortion. RESULTS: Mares bred prior to April 1, 2001, appeared to be at greatest risk of early-term abortion, both among and within individual farms. Mares bred in mid-February appeared to be at greatest risk of abortion, with an estimated weekly incidence rate of abortion of 66% (95% CI, 52% to 80%). CONCLUSIONS AND CLINICAL RELEVANCE: Mares in central Kentucky bred between mid-February and early March were observed to be at greatest risk of early-term abortion, and risk gradually decreased to a background incidence of abortion of approximately 11%. Mares bred after April 1, 2001, appeared to be at markedly less risk, indicating that exposure to the cause of MRLS likely occurred prior to this date. 相似文献
134.
135.
Indoxacarb is a novel oxadiazine pro-insecticide that has no toxic effects on the adults, fecundity and eclosion of Amblyseius fallacis (Garman), a predacious phytoseiid, or Agistemus fleschneri Summers, a predacious stigmaeid. It is toxic to Hyaliodes vitripennis (Say), a predacious mirid that has been reported from several Quebec orchards where IPM programs are used. The LC50 for this mirid is about one-half of the recommended dose (0.054 g AI litre(-1)) of indoxacarb for apple orchards. Following an application, the intoxicated mirids remained motionless as their prolegs and posterior had paralyzed. Twenty-four hours later, they appeared smaller, shrunken and severely desiccated. 相似文献
136.
137.
Cohen ND Carey VJ Donahue JG Seahorn JL Donahoe JK Williams DM Harrison LR 《Journal of the American Veterinary Medical Association》2003,222(2):199-209
OBJECTIVE: To identify factors associated with abortions of mares during late gestation attributed to mare reproductive loss syndrome (MRLS). DESIGN: Case-control study. ANIMALS: 282 broodmares from 62 farms in central Kentucky, including 137 mares that had late-term abortions (LTAs) associated with MRLS, 98 mares from the same farms that did not abort, and 48 mares that aborted from causes other than MRLS. PROCEDURE: Farm managers were interviewed to obtain data on a wide range of management practices and environmental exposures for the mares. Data for case and control horses were compared to identify risk factors for a mare having a MRLS-associated LTA (MRLS-LTA). RESULTS: Several factors increased the risk of mares having MRLS-LTAs, including increased amount of time at pasture, less time in a stall, feeding concentrate on the ground, higher proportion of diet derived from grazing pasture, being fed in pasture exclusively during the 4-week period prior to abortion, access to pasture after midnight during the 4-week period prior to abortion, and drinking from a water trough or not having access to water buckets or automatic waterers. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis indicates that exposure to pasture predisposed mares to having MRLS-LTAs and stillborn foals. Methods for limiting exposure to pasture (keeping mares in stalls longer) during environmental conditions similar to those seen in 2001 should reduce the risk of mares having MRLS-LTAs. 相似文献
138.
Seahorn JL Slovis NM Reimer JM Carey VJ Donahue JG Cohen ND 《Journal of the American Veterinary Medical Association》2003,223(6):832-838
OBJECTIVE: To identify factors significantly associated with an epidemic of fibrinous pericarditis during spring 2001 among horses in central Kentucky. DESIGN: Case-control study. ANIMALS: 38 horses with fibrinous pericarditis and 30 control horses examined for other reasons. PROCEDURE: A questionnaire was developed to solicit information regarding a wide range of management practices and environmental exposures from farm owners or managers. RESULTS: The following factors were found in bivariate analyses to be significantly associated with an increased risk of pericarditis: being from a farm with mares and foals affected by mare reproductive loss syndrome, exposure to Eastern tent caterpillars in or around horse pastures, younger age, shorter duration of residence in Kentucky and at the farm of current residence, being fed hay grown outside Kentucky, a lack of access to pond water, access to orchard grass for grazing, and a lack of direct contact with cattle. In multivariate logistic regression analyses, only variables related to caterpillar exposure and age were significantly associated with fibrinous pericarditis. CONCLUSIONS AND CLINICAL RELVANCE: Results suggest that fibrinous pericarditis in horses may be associated with mare reproductive loss syndrome. Exposure to Eastern tent caterpillars was the greatest risk factor for development of fibrinous pericarditis. The distribution of times of diagnosis of fibrinous pericarditis was consistent with a point-source epidemic. 相似文献
139.
Container-grown Ligustrum ovalifolium L. plants were used to determine the influence of nutrient availability on the mobilisation of carbon (C), nitrogen (N) and phosphorus (P) during spring growth. During the spring of the second growing season, plants either received no fertiliser, or were fertilised early (starting 17 days after bud break) or late (starting 3 months after bud break). Nutrient composition of different plant tissues was determined at several times during the second growing season from bud break to the end of elongation. Time of fertilisation did not influence aerial dry weight until flowering was completed. Plants that received no fertiliser or were fertilised late had greater root dry weight than plants that received fertiliser early. Fertilised plants had a second flush of growth after flowering completed. Nitrogen and phosphorus mobilisation occurred from bud break to the end of elongation (3 months). Nutrient mobilisation was effective in each perennial organ: root, trunk, ligneous stems and old leaves. However, the role of old leaves as storage organ was minor compared to evergreen tree leaves. Carbon mobilisation only occurred on the 1st month following bud break, before elongation. C-starch accumulation was observed in unfertilised plants even when the C-starch quantities in early fertilised plants were very low at the end of elongation, mainly in roots. In spite of fertilisation supplies, N and P quantities did not increase after elongation in the early fertilised plants, probably in relation to C insufficiency in roots to sustain N and P absorption and assimilation. By contrast, in late fertilised plants, high C quantities in roots were mobilised for N and P uptake and assimilation, which allowed both second growth flush and storage of N and P in perennial organs. The mobilisation of nutrients before and during elongation revealed the nutritional autonomy of shrubs, which could allow fertiliser use efficiency to be increased and environmental impacts to be minimised by delaying spring fertilisation. Nevertheless, the shrub ability to valorise fertilisation supplies for sustaining growth or nutrient storage restoration required sufficient C-starch quantities in roots. The starch accumulated in roots before late nutrient supply can be used for these objectives. 相似文献
140.
Influence of age and body size on gastrointestinal transit time of radiopaque markers in healthy dogs 总被引:1,自引:0,他引:1
Weber MP Stambouli F Martin LJ Dumon HJ Biourge VC Nguyen PG 《American journal of veterinary research》2002,63(5):677-682
OBJECTIVE: To compare gastric emptying time, small-intestinal transit time (SITT), and orocecal transit time (OCTT) of radiopaque markers in dogs varying in age and body size and to determine whether fecal variables (ie, consistency and moisture content) are related to gastrointestinal tract transit times in dogs. ANIMALS: 24 eight-week-old female puppies, including 6 Miniature Poodles, 6 Standard Schnauzers, 6 Giant Schnauzers, and 6 Great Danes. PROCEDURE: Gastrointestinal tract transit time experiments were performed at 12, 22, 36, and 60 weeks of age. Dogs were fed 30 small radiopaque markers mixed with a meal. Abdominal radiographs were taken. The time at which 50% of the markers had left the stomach (T50) and the time at which the first marker reached the colon were calculated. Fecal moisture content and scoring on the basis of fecal consistency were recorded during the same periods. RESULTS: Puppies had a shorter mean T50 than adults, and mean OCTT decreased significantly only during growth of large-breed dogs. However mean fecal moisture content significantly increased with age, except in Giant Schnauzers. No effect of body size on T50 was found regardless of age, and no difference was observed between OCTT of small- and large-breed adult dogs. The effect of age on the mean SITT was not significant for any breed. However, a strong positive correlation was recorded between body size and fecal moisture content (r2 = 0.77) or fecal scores (r2 = 0.69) in adult dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Age affects T50 in small- and large-breed dogs and OCTT in large-breed dogs. However, body size does not affect T50 or OCTT. A relationship does not exist between gastrointestinal tract transit time and fecal variables in healthy dogs. 相似文献