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
721.
722.
723.
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
724.
725.
726.
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
727.
728.
Sheilah A Robertson BVMS PhD Diplomate ACVA Diplomate ECVA & James E Bailey† DVM MS Diplomate ACVA 《Veterinary anaesthesia and analgesia》2002,29(4):212-218
Objective To compare the arterial pH and blood gas values, heart rate and mean arterial blood pressure, in hypoxaemic anaesthetized horses, before and after treatment, with a salbutamol (albuterol) aerosol. Animal population Eighty‐one client‐owned horses weighing between 114 and 925 kg. Fifty‐seven underwent emergency abdominal surgery and 24 were anaesthetized for elective procedures. Materials and methods Pre‐anaesthetic medication included xylazine, detomidine, butorphanol and morphine, alone or in various combinations. Induction of anaesthesia was achieved with guaifenesin and ketamine, diazepam and ketamine, or guaifenesin and thiopental. The trachea of all animals was intubated and anaesthesia maintained with either halothane (33 horses) or isoflurane (48 horses) in oxygen. Heart rate and rhythm were monitored continuously. Arterial blood pressure was monitored directly, and arterial blood collected for pH and blood gas analyses. When arterial PaO2 fell below 9.3 kPa (70 mm Hg) and failed to respond to corrective measures including positive pressure ventilation and treatment of hypotension (mean arterial blood pressures <70 mm Hg), a salbutamol aerosol (2 µg kg?1) was delivered via the endotracheal tube. Twenty minutes later, a second arterial blood sample was analysed. Results There were no significant differences in mean arterial blood pressure, heart rate, arterial pH, base excess and bicarbonate before and after treatment. Arterial O2 tension increased significantly from a mean ± SD of 8.3 ± 1.7 kPa (62.4 ± 13.1 mm Hg) before administration to 15.9 ± 9.8 kPa (119.4 ± 57.7 mm Hg) after treatment. There was a small but significant decrease in PaCO2 from 7.4 ± 1.5 kPa (55.2 ± 11.2 mm Hg) to 7.0 ± 1.3 kPa (52.9 ± 9.8 mm Hg) between sample times. No changes in heart rhythm were observed. A high percentage (approximately 70%) of animals sweated following treatment. Conclusions Salbutamol administered at a dose of 2 µg kg?1 via the endotracheal tube of anaesthetized horses with PaO2 values less than 9.3 kPa (70 mm Hg) resulted in an almost two‐fold increase in PaO2 values within 20 minutes of treatment. No changes in heart rate or mean arterial blood pressure were associated with the use of salbutamol in this study. The improvement in PaO2 may be a result of bronchodilatation and improved ventilation, increased perfusion secondary to an increase in cardiac output, or a combination of these two factors. Cardiac output and ventilation–perfusion distribution were not measured in this study; therefore, the reason for the increase in PaO2 values cannot be conclusively determined. Clinical relevance Administration of a salbutamol aerosol is a simple but effective technique that can be used to improve PaO2 values in hypoxaemic horses during inhalant anaesthesia with no apparent detrimental side effects. 相似文献
729.
The optimum dose rates of betamethasone, dexamethasone (sodium phosphate) and methylprednisolone (acetate salt) were determined for the treatment of inflammatory pain in domestic fowl using the microcrystalline sodium urate model of articular pain. The response criteria were the changes in behavioural profiles and pain-related activity over 60 minutes commencing 1 hour after an intra-articular injection of sodium urate and a course of intramuscular injections of a range of doses of each drug on the previous 2 days. The optimum dose rates for betamethasone, dexamethasone and methylprednisolone respectively were 0.04, 0.06 and 2 mg kg(-1)and are in the range of the recommended doses for these drugs in mammals. 相似文献
730.
Cecile A Carson 《Veterinary Clinics of North America: Small Animal Practice》2007,37(1):49-63; abstract viii
Treating nonverbal communication with the thoughtfulness and observation with which we approach any other clinical problem can produce a set of skills that can be applied in every encounter. Skill development begins first with enhancing one's observations of nonverbal behavior and then diagnosing whether or not the client is feeling safe. Using one or more of the nonverbal skills when clients are feeling not-safe creates more satisfaction for the client and veterinarian and motivates clients to become full partners in their animal's care. 相似文献