全文获取类型
收费全文 | 824篇 |
免费 | 45篇 |
专业分类
林业 | 10篇 |
农学 | 13篇 |
基础科学 | 3篇 |
99篇 | |
综合类 | 129篇 |
农作物 | 32篇 |
水产渔业 | 33篇 |
畜牧兽医 | 509篇 |
园艺 | 16篇 |
植物保护 | 25篇 |
出版年
2023年 | 8篇 |
2021年 | 6篇 |
2020年 | 11篇 |
2019年 | 9篇 |
2018年 | 6篇 |
2017年 | 10篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 12篇 |
2013年 | 42篇 |
2012年 | 28篇 |
2011年 | 24篇 |
2010年 | 31篇 |
2009年 | 14篇 |
2008年 | 36篇 |
2007年 | 37篇 |
2006年 | 27篇 |
2005年 | 22篇 |
2004年 | 35篇 |
2003年 | 35篇 |
2002年 | 41篇 |
2001年 | 24篇 |
2000年 | 27篇 |
1999年 | 21篇 |
1998年 | 8篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1993年 | 9篇 |
1992年 | 16篇 |
1991年 | 11篇 |
1990年 | 21篇 |
1989年 | 14篇 |
1988年 | 14篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 12篇 |
1984年 | 6篇 |
1982年 | 9篇 |
1981年 | 9篇 |
1974年 | 8篇 |
1972年 | 11篇 |
1971年 | 11篇 |
1970年 | 8篇 |
1968年 | 6篇 |
1967年 | 6篇 |
1966年 | 7篇 |
1965年 | 6篇 |
1963年 | 5篇 |
1961年 | 5篇 |
1946年 | 9篇 |
排序方式: 共有869条查询结果,搜索用时 15 毫秒
711.
Mansfield CS James FE Robertson ID 《Journal of the American Veterinary Medical Association》2008,233(6):936-944
Objective-To establish a clinical severity index that correlates severity of body system abnormalities with outcome in dogs with acute pancreatitis (AP) and determine the usefulness of serum C-reactive protein (C-RP) concentration as an objective measure of AP severity. Design-Retrospective cohort study. Animals-61 client-owned dogs with ultrasonographically or histologically confirmed AP. Procedures-Medical records of AP-affected dogs were reviewed, and signalment, physical examination findings, clinicopathologic data, and outcome (death or discharge from the hospital) were evaluated. The correlation of specific abnormalities in endocrine, hepatic, renal, hematopoietic, cardiovascular, and respiratory systems; local pancreatic complications; and intestinal integrity were evaluated, and a clinical severity index was developed for AP in dogs. The severity index score was compared with outcome and, for 12 dogs, with serum C-RP concentration. Results-The clinical severity index had a good correlation with outcome and interval from hospital admission until end point (days until outcome), but there was no difference in days until outcome between survivors and nonsurvivors. All 12 dogs evaluated had high serum C-RP concentration, but this variable was not related to outcome; however, within a 2-day period after onset of clinical signs, serum C-RP concentration in survivors and nonsurvivors differed significantly. Conclusions and Clinical Relevance-Among AP-affected dogs, the clinical severity index may be useful for treatment comparisons and prediction of intensive management requirements. Serum C-RP concentration was best related to AP severity within a 2-day period after onset of clinical signs, but daily measurement may be more useful for monitoring progress. 相似文献
712.
Gibbens JC Robertson S Willmington J Milnes A Ryan JB Wilesmith JW Cook AJ David GP 《The Veterinary record》2008,162(24):771-776
The analysis of laboratory data can provide information about the health of livestock populations; in Great Britain the Veterinary Investigation Diagnosis Analysis (VIDA) system has provided such data since 1975. However VIDA covers only known diagnoses, with limited epidemiological characterisation. The unexpected outbreak of bse showed that it was necessary to improve surveillance to detect new diseases, and a necessary update of the VIDA database for the millennium date change provided the opportunity. The information required to enhance the value of laboratory data was identified, a new form and database, 'FarmFile', were designed to record it, and they began to be used in 1999. The detection of new diseases depends on making comparisons with the expected or 'usual' levels of unexplained disease. The data are analysed quarterly to assess any changes in the levels of unexplained disease in different species, categorised in terms of clinical sign or body system, by comparison with previous years. No new diseases have been detected either through FarmFile or more traditional means since the new analyses started in earnest in 2004, but they have indicated that an unexplained event was not a new disease of concern, and developments continue to improve the system's sensitivity and specificity. 相似文献
713.
Palmer CS Traub RJ Robertson ID Devlin G Rees R Thompson RC 《Veterinary parasitology》2008,154(1-2):142-147
In a recent study of intestinal parasites in dogs and cats in Australia, Giardia was found to be the most prevalent parasite in dogs. The aim of the current study through the use of molecular tools was to determine the zoonotic significance of the Giardia and Cryptosporidium isolates recovered from dogs and cats during the Australian study. Of the isolates successfully amplified all but one of the Giardia from dogs was either Assemblage C and/or D, with one Assemblage A. Of the cat samples amplified all but one were Assemblage F, with one Assemblage D. We hypothesize that the lack of zoonotic Giardia Assemblages recovered is a result of their being a low prevalence of Giardia in the human population. The Cryptosporidium recovered from dogs and cats was determined to be C. canis and C. felis, respectively, a finding which supports growing evidence that Cryptosporidiumin companion animals is of limited public health significance to healthy people. 相似文献
714.
715.
Siti Zubaidah Ramanoon Ian Duncan Robertson John Edwards Latiffah Hassan Kamaruddin Md Isa 《Tropical animal health and production》2013,45(2):373-377
This is a retrospective study of the outbreaks of foot-and-mouth disease (FMD) in Peninsular Malaysia between 2001 and May 2007. In total, 270 outbreaks of FMD were recorded. Serotype O virus (89.95 %) and serotype A (7.7 %) had caused the outbreaks. Significant differences on the occurrence of FMD were found between the years (t?=?5.73, P?=?0.000, df?=?11), months (t?=?4.7, P?=?0.000, df?=?11), monsoon season (t?=?2.63, P?=?0.025, df?=?10) and states (t?=?4.84, P?=?0.001, df?=?10). A peak of outbreaks observed in 2003 could be due to increased animal movement and the other peak in 2006 could be due to a compromised FMD control activities due to activities on the eradication of highly pathogenic avian influenza. Cattle (86 % of outbreaks) suffered the most. However, no difference in disease occurrence between species was observed. The populations of cattle (r?=?0.672, P?=?0.023) and sheep (r?=?0.678, P?=?0.022) were significantly correlated with occurrence of FMD. Movement of animals (66 % of outbreaks) was the main source for outbreaks. A combination of control measures were implemented during outbreaks. In conclusion, the findings of this study show that FMD is endemic in Peninsular Malaysia, and information gained could be used to improve the existing control strategy. 相似文献
716.
717.
Extract A survey of the incidence of Cysticercus ovis in New Zealand was carried out in 14 selected meat works by officers of the Meat Division and Biometrics Section of the Department of Agriculture during the meat years commencing October 1, 1967, 1968, and 1969. It involved examination of some 778,000 lambs and 526,000 ewes. The detailed information from the 3 years of this survey has been summarized in the tables presented below. 相似文献
718.
719.
FJ Golder SA Robertson A Valverde DC Bolser 《Veterinary anaesthesia and analgesia》2003,30(2):115-115
Urethane is widely used as a rodent anesthetic in the laboratory setting, and is characterized as producing long‐lasting anesthesia. The purpose of this study was to evaluate the quality of anesthesia provided by a single dose of urethane based on the response to a noxious stimulus. If the quality of anesthesia was insufficient to prevent gross purposeful movement (GPM), isoflurane was also administered until no response to noxious stimulation occurred. Five adult Harlan Sprague Dawley rats (6 months of age, 250–300 g) were given urethane (1.4 g kg?1 IP) and evaluated for 120 minutes post‐injection. If the rats became laterally recumbent by 20 minutes post‐injection, a large hemostat was positioned around the tail and the response to tail clamping was assessed. If no GPM occurred, an additional 20 minutes was allowed to elapse. If the rats were not laterally recumbent or GPM was present, they were placed in a chamber and isoflurane in oxygen was administered. Inspired isoflurane concentrations (ISO) were measured using a S/5 anesthetic gas analyzer (Datex‐Ohmeda Division, Helsinki, Finland) calibrated before each experiment with a standardized calibration gas mixture (DOT‐34 NRC 300/375 m 1014, Datex‐Ohmeda Division, Helsinki, Finland). A period of 20 minutes was allowed for equilibration to inspired ISO. The tail‐clamp stimulus was then re‐applied and the animal's response recorded. If GPM was absent, ISO was lowered by 10–20% and an additional 20 minute interval elapsed. In contrast, if GPM was present, ISO was increased by 10–20%. This procedure was repeated until the ISO required to prevent GPM was determined in duplicate. The position within the estrus cycle influenced pain thresholds in the rats. As such, a vaginal smear was prepared from each rat and the position in the estrus cycle was determined based on vaginal cytology. Rats were euthanatized at the end of the study period. All values were mean ± SD. Four rats became recumbent after urethane injection (time to recumbency: 45 ± 17 seconds). Of these, two rats (one estrus, one metestrus) did not require isoflurane supplementation for the duration of the study. The three remaining rats (two metestrus, one estrus) required isoflurane supplementation. The mean ISO required to prevent GPM was 0.26 ± 0.16%. Position within the estrus cycle did not appear to affect the animal's response to urethane. These results indicate that urethane anesthesia is not long lasting in all rats and provides variable quality of anesthesia. This is of particular concern in the laboratory setting where muscle relaxants are often administered to rats shortly after urethane injection. 相似文献
720.