全文获取类型
收费全文 | 20861篇 |
免费 | 3967篇 |
国内免费 | 46篇 |
专业分类
林业 | 1437篇 |
农学 | 1008篇 |
基础科学 | 112篇 |
4513篇 | |
综合类 | 598篇 |
农作物 | 759篇 |
水产渔业 | 3481篇 |
畜牧兽医 | 10143篇 |
园艺 | 284篇 |
植物保护 | 2539篇 |
出版年
2023年 | 100篇 |
2022年 | 161篇 |
2021年 | 447篇 |
2020年 | 737篇 |
2019年 | 1231篇 |
2018年 | 1344篇 |
2017年 | 1406篇 |
2016年 | 1419篇 |
2015年 | 1150篇 |
2014年 | 1297篇 |
2013年 | 1709篇 |
2012年 | 1413篇 |
2011年 | 1426篇 |
2010年 | 1114篇 |
2009年 | 784篇 |
2008年 | 1025篇 |
2007年 | 815篇 |
2006年 | 731篇 |
2005年 | 688篇 |
2004年 | 645篇 |
2003年 | 612篇 |
2002年 | 511篇 |
2001年 | 414篇 |
2000年 | 446篇 |
1999年 | 328篇 |
1998年 | 84篇 |
1997年 | 84篇 |
1996年 | 83篇 |
1995年 | 71篇 |
1992年 | 152篇 |
1991年 | 128篇 |
1990年 | 133篇 |
1989年 | 145篇 |
1988年 | 133篇 |
1987年 | 134篇 |
1986年 | 127篇 |
1985年 | 120篇 |
1984年 | 91篇 |
1983年 | 92篇 |
1981年 | 60篇 |
1980年 | 55篇 |
1979年 | 119篇 |
1978年 | 108篇 |
1977年 | 91篇 |
1976年 | 59篇 |
1975年 | 55篇 |
1974年 | 108篇 |
1973年 | 83篇 |
1972年 | 98篇 |
1971年 | 94篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
de Carvalho Menezes de Almeida Sheylla Foligno Souza-Fabjan Joanna Maria Gonçalves Balaro Mario Felipe Alvarez Bragança Gláucia Mota Pinto Pedro Henrique Nicolau de Almeida José Gabriel Moura Ana Beatriz Bossois da Fonseca Jeferson Ferreira Brandão Felipe Zandonadi 《Tropical animal health and production》2018,50(2):427-432
Tropical Animal Health and Production - This study evaluated the effect of two doses of prostaglandin at different intervals on reproductive parameters of crossbred ewes. In Experiment 1, 30 ewes... 相似文献
102.
Paixão Sonália Ferreira Fritzen Juliana Torres Tomazi Crespo Sarah Elizabeth Izzo de Moraes Pereira Helder Alfieri Alice Fernandes Alfieri Amauri Alcindo 《Tropical animal health and production》2018,50(8):1947-1950
Tropical Animal Health and Production - Serological studies have characterized the presence of the bovine viral diarrhea virus (BVDV) infection in water buffalo herds worldwide. However, the... 相似文献
103.
Azarpajouh S. Marchewka J. Segura Correa J. C. Calderón Díaz J. A. 《Tropical animal health and production》2018,50(6):1343-1348
Tropical Animal Health and Production - The objective of this study was to compare hoof anatomy, hoof growth pattern, and hoof weight-bearing surface of six different Iranian sheep breeds to... 相似文献
104.
B. Poźniak K. Motykiewicz‐Pers T. Grabowski M. Świtała 《Journal of veterinary pharmacology and therapeutics》2018,41(1):163-165
The aim of this study was to assess the influence of growth on the pharmacokinetics of sodium salicylate (SS) in male turkeys. SS was administered intravenously at a dose of 50 mg/kg. Plasma drug concentrations were assessed by high‐performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. As the age increased from 6 to 13 weeks (body weight increase from 2.35 to 9.43 kg), median body clearance decreased from 1.34 to 0.87 ml/min/kg. This caused a significant increase in the median mean residence time from 3.42 to 4.44 hr. Elimination phase proved to be biphasic and two elimination half‐lives (T1/2el) were distinguished. Whereas T1/2el1 was found to increase with age by 128%, T1/2el2 represented a later but faster and less age‐dependent phase of elimination (increase by 56% in the respective groups). Volume of distribution decreased with age. These effects may lead to different therapeutic response to SS in turkeys of different age and body weights. 相似文献
105.
Nathaly Enciso Luciana L. K. Ostronoff Guillermo Mejías Leticia G. León María Luisa Fermín Elena Merino Cristina Fragio Luis Avedillo Concepción Tejero 《Veterinary research communications》2018,42(1):29-38
Adult Mesenchymal Stem Cells (MSC) are cells that can be defined as multipotent cells able to differentiate into diverse lineages, under appropriate conditions. These cells have been widely used in regenerative medicine, both in preclinical and clinical settings. Initially discovered in bone marrow, MSC can now be isolated from a wide spectrum of adult and foetal tissues. Studies to evaluate the therapeutic potential of these cells are based on their ability to arrive to damaged tissues. In this paper we have done a comparative study analyzing proliferation, surface markers and OCT4, SOX9, RUNX2, PPARG genes expression in MSC cells from Bone marrow (BMMSC) and Adipose tissue (ASC). We also analyzed the role of Stem Cell Factor (SCF) on MSC proliferation and on ASCs metalloproteinases MMP-2, MMP-9 secretion. Healthy dogs were used as BMMSC donors, and ASC were collected from omentum during elective ovariohysterectomy surgery. Both cell types were cultured in IMDM medium with or without SCF, 10% Dog Serum (DS), and incubated at 38 °C with 5% CO2. Growth of BMMSCs and ASCs was exponential until 25–30 days. Flow citometry of MSCs revealed positive results for CD90 and negative for CD34, CD45 and MCH-II. Genes were evaluated by RT-PCR and metalloproteinases by zymografy. Our findings indicate morphological and immunological similarities as well as expression of genes from both origins on analyzed cells. Furthermore, SCF did not affect proliferation of MSCs, however it up-regulated MMP-2 and MMP-9 secretion in ASCs. These results suggest that metalloproteinases are possibly essential molecules pivoting migration. 相似文献
106.
María Teresa Tejedor-Junco Margarita González-Martín Estefanía Bermeo-Garrido Rebeca Villasana-Loaiza Elena Carretón-Gómez 《Veterinary research communications》2018,42(3):227-232
Doxycycline is an antibiotic that, in addition to the classic antibacterial use, is also prescribed to fight parasitic diseases, like heartworm disease in dogs. Despite the concern that the overuse of this antibiotic may decrease susceptibility of clinically important bacteria, the consequences of the prolonged doxycycline therapy in heartworm-infected dogs have never been studied before. We have analyzed the impact of this therapy on Staphylococcus aureus and Enterococcus antimicrobial resistance. In this study, 17 heartworm-infected dogs (10 that had completed the doxycycline treatment and 7 dogs that had not yet begun) were included. Twenty-four isolates of Staphylococcus aureus were obtained from two locations of each dog. After treatment, 73.3% of isolates were resistant to at least one antibiotic but only 22.2% of isolates before treatment. Most of doxycycline resistant isolates were obtained from dogs that have received treatment. Erythromycin resistance or intermediate susceptibility was detected in 45.6% of isolates, most of them from dogs after treatment. For Enterococci, 48 isolates were obtained from fecal samples (25 before treatment and 23 after treatment). Before treatment, 32% of isolates were resistant at least to one antibiotic while after, this data increase up to 65%. Comparing isolates before and after treatment, a clear increase in resistance to doxycycline (12% against 21.74%) and erythromycin (20% against 39.13%) was observed. Although the present work is a preliminary research, the results encourages the development of further studies to determinate the effect of prolonged doxycycline therapy on antimicrobial resistance. 相似文献
107.
108.
Incidence and risk factors for neurological signs after attenuation of single congenital portosystemic shunts in 253 dogs
下载免费PDF全文
![点击此处可从《Veterinary surgery : VS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
109.
Effects of hyperbaric oxygen therapy on uncomplicated incisional and open wound healing in dogs
下载免费PDF全文
![点击此处可从《Veterinary surgery : VS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
110.
Laryngeal mask airway and transient hypercapnic hyperpnea for video‐endoscopic assessment of unilateral laryngeal paralysis in dogs
下载免费PDF全文
![点击此处可从《Veterinary surgery : VS》网站下载免费的PDF全文](/ch/ext_images/free.gif)