全文获取类型
收费全文 | 1091篇 |
免费 | 74篇 |
专业分类
林业 | 57篇 |
农学 | 24篇 |
基础科学 | 5篇 |
116篇 | |
综合类 | 181篇 |
农作物 | 27篇 |
水产渔业 | 71篇 |
畜牧兽医 | 577篇 |
园艺 | 30篇 |
植物保护 | 77篇 |
出版年
2024年 | 6篇 |
2023年 | 14篇 |
2022年 | 18篇 |
2021年 | 36篇 |
2020年 | 42篇 |
2019年 | 27篇 |
2018年 | 34篇 |
2017年 | 35篇 |
2016年 | 39篇 |
2015年 | 21篇 |
2014年 | 38篇 |
2013年 | 40篇 |
2012年 | 54篇 |
2011年 | 79篇 |
2010年 | 44篇 |
2009年 | 29篇 |
2008年 | 51篇 |
2007年 | 55篇 |
2006年 | 57篇 |
2005年 | 52篇 |
2004年 | 50篇 |
2003年 | 40篇 |
2002年 | 38篇 |
2001年 | 14篇 |
2000年 | 16篇 |
1999年 | 15篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 9篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 15篇 |
1987年 | 4篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1968年 | 4篇 |
1948年 | 9篇 |
排序方式: 共有1165条查询结果,搜索用时 15 毫秒
31.
Celina Y. Morimoto Monique N. Mayer Narinder Sidhu Rachel Bloomfield Cheryl L. Waldner 《Veterinary and comparative oncology》2020,18(2):199-205
Sources of residual setup error after image guidance include image localization accuracy, errors associated with image registration, and inability of some treatment couches to correct submillimeter translational errors and/or pitch and roll errors. The purpose of this experimental study was to measure setup error after image‐guided correction of the canine intracranial region, using a four degrees‐of‐freedom couch capable of 1 mm translational moves. Six cadaver dogs were positioned 45 times as for clinical treatment using a vacuum deformable body cushion, a customizable head cushion, a thermoplastic mask and an indexed maxillary plate with a dental mould. The location of five fiducial markers in the skull bones was compared between the reference position and after megavoltage (MV), kilovoltage (kV) and cone‐beam computed tomography (CBCT)‐guided correction using orthogonal kV images. The mean three‐dimensional distance vectors (3DDV) after MV, kV and CBCT‐guided correction were 1.7, 1.5 and 2.2 mm, respectively. All values were significantly different (P < .01). The 95th percentiles of the 3DDV after online MV, kV and CBCT‐guided correction were 2.8, 2.6 and 3.6 mm, respectively. Residual setup error in the clinical scenario examined was on the order of millimetres and should be considered when choosing PTV margins for image‐guided radiation therapy of the canine intracranial region. 相似文献
32.
Stöcklin-Gautschi NM Guscetti F Reichler IM Geissbühler U Braun SA Arnold S 《The Journal of small animal practice》2001,42(8):413-416
A focal uterine adenomyosis is described in two bitches. In both cases, the uterus showed knobbly enlargements of 4 to 8 cm in diameter, which resulted in distinct clinical symptoms. Other pathological changes of the uterus were not present. One bitch was presented because of a history of vaginal discharge of several months' duration. Radiographs, as well as ultrasonography, revealed a soft tissue lesion at the cervix. The other bitch showed a marked reduction in its general condition and a sudden onset of a tense abdomen. Radiologically, a lesion of soft tissue opacity was observed in the mid-abdomen and was seen to originate from the left uterine horn during exploratory laparotomy. A torsion of the lesion was present, which explained the clinical signs in this second case. 相似文献
33.
Polycythaemia vera was diagnosed in a three-year-old domestic shorthaired cat referred because of seizures and a high packed cell volume (PCV). Laboratory examination revealed severe erythrocytosis (PCV 79 per cent). Diagnosis was reached by excluding causes for relative and secondary absolute polycythaemia. As phlebotomy proved impossible for initial treatment due to hyperviscosity, four leeches were used to suck blood and the PCV was consequently reduced to 64 per cent. A further 24 hours later, when bleeding at the sites of sucking had stopped, the PCV was 56 per cent. Long-term management of the condition was achieved with hydroxyurea (100 mg/cat once daily) and intermittent phlebotomy. Initial treatment using leeches in cases of polycythaemia vera is a simple, non-invasive, well tolerated and effective method where phlebotomy is not possible. 相似文献
34.
Jill A. Richardson DVM Rachel A. Balabuszko CVT 《Journal of Veterinary Emergency and Critical Care》2001,11(1):53-58.
Objective: To summarize typical clinical signs, characterize the anticipated course of action, and give treatment recommendations for ibuprofen ingestion in ferrets.
Design: Retrospective study
Patients: Records of 43 cases of ibuprofen ingestion in ferrets that were reported between January 1996-March 2000, to the ASPCA Animal Poison Control Center (APCC).
Measurements and Main Results: Twenty-seven (93.1%) ferrets that had ingested ibuprofen developed neurologic signs, such as depression, coma, ataxia, recumbency, tremors, and weakness. In addition, 16 cases (55.2%) had one or more GI effects including anorexia, vomiting, retching or gagging, diarrhea, and melena. Polydipsia, polyuria, dysuria, renal failure, weight loss, shallow breathing, metabolic acidosis, dehydration, and hypothermia were also reported. Death was reported in 4 cases. The lowest dose associated with death was 220 mg/kg.
Conclusion: Data in this study indicate that clinical signs of ibuprofen toxicosis in ferrets are more severe than those expected at similar dosages in dogs. The reason for this difference is poorly understood since the pathophysiology of ibuprofen is relatively unknown in ferrets. The onset of clinical signs appeared to occurr soon after ingestion and the toxic effects in ferrets typically involve the CNS, GI and renal systems. Treatment for ibuprofen toxicosis in the ferret includes stabilization, gastrointestinal decontamination, fluid diuresis, GI protection, and supportive care.(J Vet Emerg Crit Care 2001; 11(1):53–59) 相似文献
Design: Retrospective study
Patients: Records of 43 cases of ibuprofen ingestion in ferrets that were reported between January 1996-March 2000, to the ASPCA Animal Poison Control Center (APCC).
Measurements and Main Results: Twenty-seven (93.1%) ferrets that had ingested ibuprofen developed neurologic signs, such as depression, coma, ataxia, recumbency, tremors, and weakness. In addition, 16 cases (55.2%) had one or more GI effects including anorexia, vomiting, retching or gagging, diarrhea, and melena. Polydipsia, polyuria, dysuria, renal failure, weight loss, shallow breathing, metabolic acidosis, dehydration, and hypothermia were also reported. Death was reported in 4 cases. The lowest dose associated with death was 220 mg/kg.
Conclusion: Data in this study indicate that clinical signs of ibuprofen toxicosis in ferrets are more severe than those expected at similar dosages in dogs. The reason for this difference is poorly understood since the pathophysiology of ibuprofen is relatively unknown in ferrets. The onset of clinical signs appeared to occurr soon after ingestion and the toxic effects in ferrets typically involve the CNS, GI and renal systems. Treatment for ibuprofen toxicosis in the ferret includes stabilization, gastrointestinal decontamination, fluid diuresis, GI protection, and supportive care.(J Vet Emerg Crit Care 2001; 11(1):53–59) 相似文献
35.
Luo Y Sahin O Dai L Sippy R Wu Z Zhang Q 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2012,74(5):591-596
Loop-mediated isothermal amplification (LAMP) assay is a simple, rapid and specific detection method and has been used for detection and identification of different Campylobacter species. In this study, we develop a LAMP assay specific for detection of a particular clone (clone SA) of Campylobacter jejuni, associated with the vast majority of recent sheep abortions in the U.S. Using a set of specific primers for C. jejuni IA3902 (a clone SA isolate) and genomic DNA or boiled cell extract as template, the target DNA was amplified at 63 °C for 50 min in a water bath. A positive reaction was identified visually as white precipitate or fluorescence under UV, and confirmed by gel electrophoresis. Detection limit of the assay was comparable to that of conventional PCR. The LAMP was shown to be specific for detection of clone SA when tested on a number of C. jejuni strains of different genetic backgrounds. Applicability of the LAMP assay for specific detection of clone SA was demonstrated in animal tissues experimentally infected with IA3902 or genetically diverse C. jejuni strains. Since clone SA is the predominant cause of sheep abortions in the U.S. and is a zoonotic pathogen, the LAMP assay may be a valuable detection tool in future epidemiological studies. 相似文献
36.
This study was conducted to ascertain the effect of autoclaving, source of calcium and phosphate, vitamin D3 level and strain of turkey poults on the rachitogenic activity of isolated soybean protein (C‐1 protein‐Skidmore). One‐day‐old poults were fed purified diets of the glucose—C‐1 protein type. The diets contained calcium, phosphorus and vitamin D3 at levels equal to or greater than the National Research Council's (1960) recommendations. The findings demonstrate that USP hydrated dicalcium phosphate was more effective than food‐grade dicalcium phosphate in overcoming the rachitogenic activity of the C‐1 protein. Autoclaving the C‐1 protein for 80 min destroyed its rachitogenic activity: Vitamin D3 was also effective in reducing the rachitogenic effect of C‐1 protein. The Broad Breasted White strain proved to be more susceptible to the rachitogenic property of C‐1 protein than the Wrolstad Small White strain. Substituting USP hydrated dicalcium phosphate for food‐grade dicalcium phosphate, autoclaving the C‐1 protein or increasing the vitamin D3 level increased body weight gains and tibia ash values. The interactions which were shown to exist between source of calcium and phosphate × autoclaving, strain × autoclaving, and vitamin D3 level × strain demonstrate an interrelationship between these factors. 相似文献
37.
Rachel C. Hector Marlis L. Rezende Khursheed R. Mama Eugene P. Steffey Heather K. Knych Ann M. Hess Juhana M. Honkavaara Marja R. Raekallio Outi M. Vainio 《Veterinary anaesthesia and analgesia》2017,44(4):755-765
Objective
To determine the effects of low and high dose infusions of dexmedetomidine and a peripheral α2-adrenoceptor antagonist, MK-467, on sevoflurane minimum alveolar concentration (MAC) in dogs.Study design
Crossover experimental study.Animals
Six healthy, adult Beagle dogs weighing 12.6 ± 0.9 kg (mean ± standard deviation).Methods
Dogs were anesthetized with sevoflurane in oxygen. After a 60-minute instrumentation and equilibration period, the MAC of sevoflurane was determined in triplicate using the tail clamp technique. PaCO2 and temperature were maintained at 40 ± 5 mmHg (5.3 ± 0.7 kPa) and 38 ± 0.5 ºC, respectively. After baseline MAC determination, dogs were administered two incremental loading and infusion doses of either dexmedetomidine (1.5 μg kg?1 then 1.5 μg kg?1 hour?1 and 4.5 μg kg?1 then 4.5 μg kg?1 hour?1) or MK-467 (90 μg kg?1 then 90 μg kg?1 hour?1 and 180 μg kg?1 then 180 μg kg?1 hour?1); loading doses were administered over 10 minutes. MAC was redetermined in duplicate starting 30 minutes after the start of drug administration at each dose. End-tidal sevoflurane concentrations were corrected for calibration and adjusted to sea level. A repeated-measures analysis was performed and comparisons between doses were conducted using Tukey's method. Statistical significance was considered at p < 0.05.Results
Sevoflurane MAC decreased significantly from 1.86 ± 0.3% to 1.04 ± 0.1% and 0.57 ± 0.1% with incremental doses of dexmedetomidine. Sevoflurane MAC significantly increased with high dose MK-467, from 1.93 ± 0.3% to 2.29 ± 0.5%.Conclusions and clinical relevance
Dexmedetomidine caused a dose-dependent decrease in sevoflurane MAC, whereas MK-467 caused an increase in MAC at the higher infusion dose. Further studies evaluating the combined effects of dexmedetomidine and MK-467 on MAC and cardiovascular function may elucidate potential benefits of the addition of a peripheral α2-adrenergic antagonist to inhalation anesthesia in dogs. 相似文献38.
39.
Students in veterinary schools can experience stress in balancing the different demands on them-academic, interpersonal, intrapersonal, and professional or work related-as well as managing potential conflict between animal and human interests. Practicing veterinarians report many similar stressors and reactions. Stressful stimuli produce stress reactions that can be inimical to physical and psychological well-being, and students' performance in veterinary programs can be adversely affected if they do not have coping resources. While there has been some research into stress among university students in general, and among medical students in particular, there is little on the experience of veterinary students. This article describes a study by the School of Psychology, commissioned by the Department of Veterinary Clinical Sciences, at Murdoch University in Western Australia. It was designed to investigate the levels and causes of stress among, and the frequency and type of coping strategies used by, fourth- and fifth-year students. Results indicate that the students in this cohort faced frequent stressors and felt at least moderately stressed but did not routinely and systematically use a range of coping strategies. Academic stressors and perceived responsibilities attached to moving into practical or professional areas figured strongly and were associated with higher levels of stress in the students, in particular physical sequelae. Though the numbers were small, it is of concern that some students were using measures that were potentially harmful. Some recommendations are made here about measures that veterinary programs may be able to incorporate to address stress in their students. Information is included on current strategies within the curriculum to manage potential stressful situations as part of students' professional development. 相似文献
40.