全文获取类型
收费全文 | 6744篇 |
免费 | 3485篇 |
国内免费 | 5篇 |
专业分类
林业 | 208篇 |
农学 | 449篇 |
基础科学 | 6篇 |
1358篇 | |
综合类 | 93篇 |
农作物 | 121篇 |
水产渔业 | 2522篇 |
畜牧兽医 | 4130篇 |
园艺 | 63篇 |
植物保护 | 1284篇 |
出版年
2023年 | 17篇 |
2022年 | 24篇 |
2021年 | 150篇 |
2020年 | 484篇 |
2019年 | 1047篇 |
2018年 | 917篇 |
2017年 | 957篇 |
2016年 | 951篇 |
2015年 | 821篇 |
2014年 | 815篇 |
2013年 | 982篇 |
2012年 | 487篇 |
2011年 | 506篇 |
2010年 | 617篇 |
2009年 | 263篇 |
2008年 | 240篇 |
2007年 | 85篇 |
2006年 | 114篇 |
2005年 | 101篇 |
2004年 | 108篇 |
2003年 | 106篇 |
2002年 | 114篇 |
2001年 | 72篇 |
2000年 | 102篇 |
1999年 | 12篇 |
1998年 | 7篇 |
1997年 | 13篇 |
1996年 | 8篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 12篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 3篇 |
1970年 | 4篇 |
1966年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Stephen J Hernandez-Divers Robert S Bakal Brian H Hickson Clarence A Rawlings Heather G Wilson MaryAnn Radlinsky Sonia M Hernandez-Divers Samuel R Dover 《Journal of zoo and wildlife medicine》2004,35(4):459-470
Seventeen Gulf of Mexico sturgeons (Acipenser oxyrinchus desotoi) underwent endoscopic sex determination, gonadal biopsy, and various reproductive surgeries as part of a conservation development plan. The fish were anesthetized with tricaine methanesulfonate (MS-222) buffered with sodium bicarbonate and maintained on a recirculating water anesthesia circuit. A 6-mm Ternamian EndoTip Cannula, placed through the ventral midline, midway between pectoral and pelvic fins, permitted the introduction of a 5-mm telescope. Swim bladder aspiration and CO2 insufflation of the coelomic cavity provided excellent observation. Second and third cannulae were placed under direct visual control, lateral and cranial or caudal to the telescope cannula. Sex determination was successfully performed in all fish; however, five of 17 sturgeons (29%) required endoscopic gonadal biopsy to confirm sex. Bilateral ovariectomy or orchidectomy was successfully performed in three males and four females. Unilateral ovariectomy and bilateral ligation of the müllerian ducts using an extracorporeal suturing technique was accomplished in an additional three females. No apparent morbidity was associated with the anesthesia or endoscopic surgery in any fish. The ability to safely perform minimally invasive reproductive surgery in fish may have important management and conservation benefits. 相似文献
23.
K. Jung Y. Ha S.‐K. Ha D. U. Han D.‐W. Kim W. K. Moon C. Chae 《Zoonoses and public health》2004,51(2):72-76
The aim of these experiments was to investigate the potential antiviral effect of Saccharomyces cerevisiaeβ‐glucan on the pneumonia induced by swine influenza virus (SIV). Forty colostrum‐deprived 5‐day‐old piglets were randomly divided into four groups of 10. The 20 pigs in groups 1 and 2 were administered Saccharomyces cerevisiaeβ‐glucan orally (50 mg/day/pig; En‐Bio Technology Co., Ltd) for 3 days before SIV infection and those in groups 3 and 4 were given culture medium/diluent alone. Groups 1 and 3 were inoculated intranasally with 3 ml of tissue culture fluid containing 2 × 106 tissue culture infective doses 50% (TCID50)/ml of SIV and those in groups 2 and 4 were exposed in the same manner to uninfected cell culture supernatant. The microscopic lung lesions induced by SIV infection (group 1 pigs) were significantly more severe than those induced by infection in animals pre‐administered β‐glucan (group 3) (P < 0.05). Significantly more SIV nucleic acid was detected in the lungs of pigs experimentally infected with SIV only (group 1) at 5, 7 and 10 days post‐inoculation (dpi) compared with lungs from pigs pre‐administered β‐glucan and infected with SIV (group 3) (P < 0.05). The concentrations of interferon‐γ (IFN‐γ) and nitric oxide (NO) in bronchoalveolar lavage fluid from pigs pre‐administered β‐glucan and infected with SIV (group 3) were significantly higher than for any other group at 7 and 10 dpi for IFN‐γ, and at 5, 7 and 10 dpi for NO (P < 0.05). Saccharomyces cerevisiaeβ‐glucan reduced the pulmonary lesion score and viral replication rate in SIV‐infected pigs. These findings support the potential application of β‐glucan as prophylactic/treatment agent in influenza virus infection. 相似文献
24.
DW Bartlett JM Clough JR Godwin AA Hall M Hamer B Parr‐Dobrzanski 《Pest management science》2004,60(3):309-309
The original article to which this Correction refers was published in Pest Management Science 58 (7): 649–662 (2002).Copyright © 2004 Society of Chemical Industry 相似文献
25.
Ultrastructure of the tubular glands in the isthmus region of the oviduct in laying and natural moulting commercial egg‐type chickens
下载免费PDF全文
![点击此处可从《Anatomia, histologia, embryologia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mary‐Cathrine Nyasha Madekurozwa Mike M. Mpango 《Anatomia, histologia, embryologia》2018,47(5):493-497
The study investigated the ultrastructural characteristics of tubular gland and duct cells, as well as luminal gland cells in the isthmus region of the oviduct of laying and natural moulting hens. Tubular glands in laying birds were composed of type 1 and 2 cells. Based on the preponderance of each cell type, in relation to the location of a developing egg in the oviduct of the domestic fowl, these gland cells may represent different functional states of the same cell. The findings of the study on natural moulting birds suggest that autophagy is a process confined to the early stages of degeneration, while necrosis occurs in the terminal stages. 相似文献
26.
27.
Fracture of the medial intercondylar eminence of the tibia in horses treated by arthroscopic fragment removal (21 horses)
下载免费PDF全文
![点击此处可从《Equine veterinary journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
28.
29.
An improved vitrification protocol for equine immature oocytes,resulting in a first live foal
下载免费PDF全文
![点击此处可从《Equine veterinary journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
30.