全文获取类型
收费全文 | 6076篇 |
免费 | 682篇 |
国内免费 | 150篇 |
专业分类
林业 | 375篇 |
农学 | 480篇 |
基础科学 | 135篇 |
1067篇 | |
综合类 | 1067篇 |
农作物 | 303篇 |
水产渔业 | 624篇 |
畜牧兽医 | 2101篇 |
园艺 | 171篇 |
植物保护 | 585篇 |
出版年
2024年 | 9篇 |
2023年 | 98篇 |
2022年 | 118篇 |
2021年 | 117篇 |
2020年 | 154篇 |
2019年 | 197篇 |
2018年 | 303篇 |
2017年 | 314篇 |
2016年 | 250篇 |
2015年 | 247篇 |
2014年 | 294篇 |
2013年 | 365篇 |
2012年 | 386篇 |
2011年 | 415篇 |
2010年 | 338篇 |
2009年 | 283篇 |
2008年 | 362篇 |
2007年 | 321篇 |
2006年 | 269篇 |
2005年 | 254篇 |
2004年 | 179篇 |
2003年 | 157篇 |
2002年 | 137篇 |
2001年 | 203篇 |
2000年 | 201篇 |
1999年 | 136篇 |
1998年 | 54篇 |
1997年 | 63篇 |
1996年 | 47篇 |
1995年 | 52篇 |
1994年 | 28篇 |
1993年 | 29篇 |
1992年 | 44篇 |
1991年 | 54篇 |
1990年 | 53篇 |
1989年 | 34篇 |
1988年 | 41篇 |
1987年 | 30篇 |
1986年 | 28篇 |
1985年 | 19篇 |
1984年 | 14篇 |
1983年 | 15篇 |
1982年 | 11篇 |
1979年 | 14篇 |
1978年 | 8篇 |
1971年 | 7篇 |
1970年 | 8篇 |
1967年 | 12篇 |
1966年 | 10篇 |
1892年 | 7篇 |
排序方式: 共有6908条查询结果,搜索用时 15 毫秒
21.
Le Garreres A Laroute V De La Farge F Boudet KG Lefebvre HP 《Journal of Feline Medicine and Surgery》2007,9(2):89-96
The objectives of this study were to compare assay methods for plasma creatinine (Pl-creat) in cats and to describe the disposition of creatinine and iohexol in 12 healthy and moderately azotaemic cats. Exogenous creatinine and iohexol were injected simultaneously by intravenous bolus, and repeated blood samples were taken to determine the pharmacokinetic parameters of each marker. Pl-creat was assayed by high-performance liquid chromatography (HPLC), Jaffé and enzymatic methods. The enzymatic method was shown to be more reliable than the Jaffé method. Two stereoisomers, exo- and endo-iohexol were identified. The plasma clearance of creatinine (2.3+/-0.66 ml/min/kg) was significantly higher (P<0.001) than that of exo-iohexol (1.7+/-0.40 ml/min/kg). The volume of distribution (447+/-97 ml/kg) and elimination half-life (181+/-77 min) of creatinine were also higher (P<0.001) than those of exo- and endo-iohexol. The estimated daily endogenous production of creatinine was 65+/-23 mg/kg. None of the pharmacokinetic parameters was changed by the azotaemic status of the animals. 相似文献
22.
Montané J Marco I Manteca X López J Lavín S 《Journal of veterinary medicine. A, Physiology, pathology, clinical medicine》2002,49(2):93-98
Delayed acute capture myopathy is the term used to describe the clinical syndrome observed in three roe deer captured by drive-nets and transported to an enclosure for scientific purposes. The animals died 48 h, 60 h and 8 days after being captured. The simultaneous deaths coincided with a previous episode of deliberate human disturbance. The histopathological findings were indicative of acute myopathy and myoglobinaemic nephrosis. These could be related to an ataxic myoglobinuric syndrome brought on by capture and transport operations. The lack of clinical signs and negative prognosis indicators in the period between capture and just before death. the absence of gross muscular lesions in the animal that died after 8 days post-capture, the simultaneous deaths of animals captured at different times and the evidence of deliberate human disturbance in the enclosure are suggestive of death triggered by a second stress episode. 相似文献
23.
Le Bouquin S Allain V Rouxel S Petetin I Picherot M Michel V Chemaly M 《Preventive veterinary medicine》2010,97(3-4):245-251
A nation-wide survey was carried out in 370 randomly chosen French commercial broiler chicken flocks from October 2005 to September 2006 to determine Salmonella spp. prevalence and to identify risk factors for contamination, at the end of the rearing period. The Salmonella status of the flocks was assessed from five faecal samples (litter swabs) analysed by classical bacteriological methods. A flock with at least one contaminated sample was classified as a Salmonella-positive flock. The apparent prevalence of Salmonella was 8.6% (95% CI: 5.7, 11.5%). The most prevalent serovar was S. hadar followed by S. anatum and S. mbandaka. Logistic regression methods were used to analyse the associations between husbandry practices, farm characteristics, general hygiene and the Salmonella status of the sample. The risk for Salmonella contamination of the flock at the end of the rearing period increased when neighbours helped in the placement of day-old chicks. On the contrary, the risk decreased when mobile equipment was dismantled before cleaning and disinfection, when the farm had a specific container for dead-bird disposal and when acetic acid was added to the drinking water. 相似文献
24.
C. Elwood P. Devauchelle J. Elliott V. Freiche A. J. German M. Gualtieri E. Hall E. den Hertog R. Neiger D. Peeters X. Roura K. Savary-Bataille 《The Journal of small animal practice》2010,51(1):4-22
Emesis is a common presenting sign in small animal practice. It requires a rational approach to management that is based upon a sound understanding of pathophysiology combined with logical decision making. This review, which assesses the weight of available evidence, outlines the physiology of the vomiting reflex, causes of emesis, the consequences of emesis and the approach to clinical management of the vomiting dog. The applicability of diagnostic testing modalities and the merit of traditional approaches to management, such as dietary changes, are discussed. The role and usefulness of both traditional and novel anti-emetic drugs is examined, including in specific circumstances such as following cytotoxic drug treatment. The review also examines areas in which common clinical practice is not necessarily supported by objective evidence and, as such, highlights questions worthy of further clinical research. 相似文献
25.
26.
F. YANG N. SUN Y. X. SUN Q. SHAN H. Y. ZHAO D. P. ZENG Z. L. ZENG 《Journal of veterinary pharmacology and therapeutics》2013,36(2):192-200
Yang, F., Sun, N., Sun, Y. X., Shan, Q., Zhao, H. Y., Zeng, D. P., Zeng, Z. L. A physiologically based pharmacokinetics model for florfenicol in crucian carp and oral‐to‐intramuscular extrapolation. J. vet. Pharmacol. Therap. 36 , 192–200. In this study, an oral physiologically based pharmacokinetics (PBPK) model was developed for florfenicol in crucian carp (Carassius auratus). Subsequently, oral‐to‐intramuscular extrapolation was performed and the two models were used to predict florfenicol concentrations in the edible tissues of crucian carp. The oral model gave good predictions in most tissues, except for kidney and liver in which the florfenicol concentrations were underestimated at the later time points. In contrast, using the intramuscular model, the concentrations in the kidney were overestimated at the later time points. Both models had the best predictive ability in the main edible tissue, the muscle. The oral model also accurately predicted the florfenicol concentrations in the muscle after multiple doses. The present study demonstrated the feasibility of predicting florfenicol concentrations in the edible tissues of crucian carp using a route‐to‐route extrapolation method. 相似文献
27.
28.
29.
To evaluate the effect of Spanish summer commercial journeys on the stress response of young bulls born and reared under extensive conditions, 2 replicates of a transport from an assembly centre to a growing-finishing farm were studied. Journeys lasted 27 h, involving a total of 62 young bulls. Variables under study included haematocrit, red blood cell count (RBC), total white blood cell count (WBC), differential WBC counts, serum haptoglobin (Hp), cortisol, glucose, creatine phosphokinase (CPK), lactate dehydrogenase (LDH), total protein, and albumin at loading, at the end of an intermediate market stop, and at the unloading. Before the beginning of the journey elevated WBC and neutrophil counts, and high Hp values were detected, reflecting high stress levels probably as a consequence of previous procedures associated with the grouping at the assembly centre. Some stress was also detected at the end of the market stop, with cortisol increasing from 6.5 to 12.6 ± 2.0 ng/mL (P < 0.001), although a change in Hp concentration was not observed. Neither CPK and LDH activities, related to muscular tissue damage, nor haematocrit and RBC count, related to dehydration revealed a significant effect of this first stage of the journey on the physical stress of the young bulls. Subsequent 13 h transport to the growing-finishing farm induced an increase in Hp levels from 0.48 to 0.78 ± 0.16 mg/mL (P < 0.001), reflecting an onset of the acute stress response, although cortisol levels immediately after the unloading were similar to those found before loading at the market, suggesting that calves got accustomed to transport. At the end of the journey some dehydration and physical stress were also detected. Overall, our study provides new information to the discussion of the effect of temperatures during cattle transport. Although an improvement in pre-transport conditions is essential if the welfare of assembled and transported cattle is to be improved, the stress-related alteration of cattle physiology under Spanish summer commercial transport conditions is similar to that observed under colder conditions. 相似文献
30.