全文获取类型
收费全文 | 554篇 |
免费 | 32篇 |
专业分类
林业 | 29篇 |
农学 | 21篇 |
基础科学 | 1篇 |
78篇 | |
综合类 | 40篇 |
农作物 | 137篇 |
水产渔业 | 70篇 |
畜牧兽医 | 175篇 |
园艺 | 8篇 |
植物保护 | 27篇 |
出版年
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 24篇 |
2020年 | 12篇 |
2019年 | 14篇 |
2018年 | 17篇 |
2017年 | 10篇 |
2016年 | 26篇 |
2015年 | 20篇 |
2014年 | 29篇 |
2013年 | 33篇 |
2012年 | 47篇 |
2011年 | 58篇 |
2010年 | 29篇 |
2009年 | 26篇 |
2008年 | 32篇 |
2007年 | 37篇 |
2006年 | 28篇 |
2005年 | 26篇 |
2004年 | 21篇 |
2003年 | 16篇 |
2002年 | 15篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 7篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1964年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有586条查询结果,搜索用时 0 毫秒
101.
Five new nardosinane-type sesquiterpenoids, paralemnolins Q-U (1-5), along with three known compounds (6-8), were isolated from the Formosan soft coral Paralemnalia thyrsoides. The structures of new metabolites were elucidated on the basis of extensive spectroscopic methods, and the absolute configuration of 1 was determined by the application of Mosher's method on 1. Among these metabolites, 1 and 3 are rarely found nardosinane-type sesquiterpenoids, possessing novel polycyclic structures. Compounds 1, 3, 6 and 7 were found to possess neuroprotective activity. 相似文献
102.
Heon Woong Kim Sung Ryong Kim Young Min Lee Hwan Hee Jang Jung Bong Kim 《Potato Research》2018,61(1):1-17
Anthocyanin concentration and composition and the effect of steaming and baking on these were evaluated in tubers of Korean red- and purple-fleshed potato cultivars and breeding clones using liquid chromatography with diode array detection and electrospray ionization-mass spectrometry (LC-DAD-ESI-MS). Twenty-six anthocyanins were isolated, of which 24 were identified. Remarkably, five cis isomers were identified, of which four, viz., cis-petanin, cis-peonanin, petunidin 3-cis-caffeoylrutinoside-5-glucoside, and petunidin 3-cis-feruloylrutinoside-5-glucoside, are reported for the first time. Moreover, pelargonidin 3-p-coumaroylrutinoside-5-glucoside (pelanin), peonidin 3-p-coumaroylrutinoside-5-glucoside (peonanin) and petunidin 3-p-coumaroylrutinoside-5-glucoside (petanin) were identified as the principal anthocyanins. We found that the total anthocyanin content of coloured potatoes was decreased by steaming and baking compared with the raw state. In addition, we performed partial least square discriminant analysis (PLS-DA) to discriminate between the analyzed anthocyanins. Cis isomers seemed to play a vital role as a biomarker in the PLS-DA model based on the type of processing and colour of the tubers. 相似文献
103.
Zinc oxide (ZnO) and silicon carbide (SiC) nanoparticles were compounded with polyethylene terephthalate (PET) by using a twin screw extruder, and their effect on the UV absorption and heat transfer in PET/ZnO and PET/SiC composite films was investigated. The presence of ZnO and SiC in the PET matrix was verified by X-ray diffraction. The UV absorbance of both PET/ZnO and PET/SiC composite films increased with increasing particle content. The UV absorbance of PET/SiC was higher than that of PET/ZnO under the same particle content. A thermal imaging camera was used to analyze the heat transfer in PET/ZnO and PET/SiC composite films after heating them to 40 °C. As the content of ZnO and SiC particles increased, the temperature decreased more rapidly. PET/SiC showed faster cooling than PET/ZnO because of the higher thermal conductivity of SiC compared to that of ZnO. Response temperature surfaces for PET/ZnO and PET/SiC were obtained by using an exponential decay function and a second order equation, and the elapsed times to cool to room temperature were estimated. 相似文献
104.
Li-Hsueh Wang Jyh-Horng Sheu Shih-Yao Kao Jui-Hsin Su Yung-Husan Chen Yu-Hsin Chen Yin-Di Su Yu-Chia Chang Lee-Shing Fang Wei-Hsien Wang Yang-Chang Wu Ping-Jyun Sung 《Marine drugs》2012,10(11):2415-2434
The structures, names, bioactivities and references of 105 natural products obtained from gorgonian corals belonging to the family Plexauridae with an Indo-Pacific distribution are described in this review. All compounds mentioned in this review were obtained from gorgonian corals belonging to the genera Astrogorgia, Bebryce, Echinomuricea, Euplexaura and Menella. 相似文献
105.
Sung PJ Li GY Su YD Lin MR Chang YC Kung TH Lin CS Chen YH Su JH Lu MC Kuo J Weng CF Hwang TL 《Marine drugs》2010,8(10):2639-2646
Two new 12-hydroxybriarane diterpenoids, designated as excavatoids O (1) and P (2), were isolated from the octocoral Briareum excavatum. The structures of briaranes 1 and 2 were established on the basis of extensive spectral data analysis. Excavatoid P (2) is the first metabolite which possesses a 6β -chlorine atom in briarane analogues. 相似文献
106.
107.
Sung Jae Shin Seung Won Shin Mi Lan Kang Deog Yong Lee Moon-Sik Yang Yong-Suk Jang Han Sang Yoo 《Journal of veterinary science (Suw?n-si, Korea)》2007,8(4):383-392
We previously induced protective immune response by oral immunization with yeast expressing the ApxIIA antigen. The ApxI antigen is also an important factor in the protection against Actinobacillus pleuropneumoniae serotype 5 infection; therefore, the protective immunity in mice following oral immunization with Saccharomyces cerevisiae expressing either ApxIA (group C) or ApxIIA (group D) alone or both (group E) was compared with that in two control groups (group A and B). The immunogenicity of the rApxIA antigen derived from the yeast was confirmed by a high survival rate and an ApxIA-specific IgG antibody response (p < 0.01). The highest systemic (IgG) and local (IgA) humoral immune responses to ApxIA and ApxIIA were detected in group E after the third immunization (p < 0.05). The levels of IL-1β and IL-6 after challenge with an A. pleuropneumoniae field isolate did not change significantly in the vaccinated groups. The level of TNF-α increased in a time-dependent manner in group E but was not significantly different after the challenge. After the challenge, the mice in group E had a significantly lower infectious burden and a higher level of protection than the mice in the other groups (p < 0.05). The survival rate in each group was closely correlated to the immune response and histopathological observations in the lung following the challenge. These results suggested that immunity to the ApxIA antigen is required for optimal protection. 相似文献
108.
Sung HW 《Avian diseases》2002,46(3):517-524
The incidence of Marek's disease (MD), an important neoplastic disease of chickens, suddenly increased in 1997 in Korea. Most MD cases of this country were detected in chickens over 20 wk of age. Five MD viruses were isolated from field flocks in which severe MD losses had occurred, and one of the viruses was studied to compare its pathotype with the prototype JM strain. The isolate KOMD-IC induced severe depression not only in body weight but also in relative bursal weight, and the depression by KOMD-IC was more severe than that induced by JM strain. In addition, the incidence of MD tumor caused by KOMD-IC was higher than that caused by the JM strain. The protective capacity of several MD vaccines was studied against challenge with KOMD-IC. The protective levels of several MD vaccines such as herpesvirus of turkeys (HVT), HVT plus SB1, and Rispens were usually lower against challenge with KOMD-IC than those challenged with JM strain, even if the chickens vaccinated with serotype 1 were not completely protected against challenge with KOMD-IC. The above results indicate that the virulence of KOMD-IC isolated recently was increased, and the increase of MD outbreak in Korea may be related to the virulence increase of the virus. Various MD vaccine programs were applied to reduce MD loss to a broiler breeder farm where severe MD loss had occurred. Serotype 1 vaccine could dramatically decrease the mortality due to MD, and the best results were obtained from the flocks vaccinated with bivalent vaccine of Rispens and HVT. 相似文献
109.
Objective To describe clinical and virological findings of an outbreak of ocular disease attributed to naturally-acquired primary canine herpesvirus-1 (CHV-1) infection in a closed domestic dog colony.
Animals studied Twenty-seven 10- to 16-week-old laboratory Beagles.
Procedure Complete ophthalmic examinations were performed and ocular samples collected for CHV-1 polymerase chain reaction and virus isolation.
Results The prevalence of ocular morbidity was 100% in examined dogs. Lesions were restricted to the ocular surface and included bilateral conjunctivitis (100% of dogs); punctate, dendritic, or geographic ulcerative keratitis (26% of dogs); and non-ulcerative keratitis (19% of dogs). Conjunctival petechiae were detected in 22% of dogs. Punctate and dendritic corneal ulcers were frequently organized into discrete groups or linear arrangements. Non-ulcerative keratitis appeared clinically as a perilimbal ring of superficial corneal vascularization and leukocyte infiltration. CHV-1 was detected in ocular samples by polymerase chain reaction or virus isolation in all dogs sampled.
Conclusions In susceptible populations of domestic dogs, CHV-1 may be associated with outbreaks of highly contagious ocular infection in the absence of concurrent overt systemic disease. This naturally-acquired outbreak of CHV-1 infection provides an opportunity to report the spectrum and prevalence of ocular lesions associated with primary ocular CHV-1 infection in dogs. Conjunctivitis was the most frequent ocular lesion detected. Ulcerative and non-ulcerative keratitis were less prevalent and of variable clinical appearance. Dendritic ulcerative keratitis, a classic and relatively specific ocular lesion associated with alphaherpesvirus infection, was detected in < 20% of dogs. 相似文献
Animals studied Twenty-seven 10- to 16-week-old laboratory Beagles.
Procedure Complete ophthalmic examinations were performed and ocular samples collected for CHV-1 polymerase chain reaction and virus isolation.
Results The prevalence of ocular morbidity was 100% in examined dogs. Lesions were restricted to the ocular surface and included bilateral conjunctivitis (100% of dogs); punctate, dendritic, or geographic ulcerative keratitis (26% of dogs); and non-ulcerative keratitis (19% of dogs). Conjunctival petechiae were detected in 22% of dogs. Punctate and dendritic corneal ulcers were frequently organized into discrete groups or linear arrangements. Non-ulcerative keratitis appeared clinically as a perilimbal ring of superficial corneal vascularization and leukocyte infiltration. CHV-1 was detected in ocular samples by polymerase chain reaction or virus isolation in all dogs sampled.
Conclusions In susceptible populations of domestic dogs, CHV-1 may be associated with outbreaks of highly contagious ocular infection in the absence of concurrent overt systemic disease. This naturally-acquired outbreak of CHV-1 infection provides an opportunity to report the spectrum and prevalence of ocular lesions associated with primary ocular CHV-1 infection in dogs. Conjunctivitis was the most frequent ocular lesion detected. Ulcerative and non-ulcerative keratitis were less prevalent and of variable clinical appearance. Dendritic ulcerative keratitis, a classic and relatively specific ocular lesion associated with alphaherpesvirus infection, was detected in < 20% of dogs. 相似文献
110.
Y Y Sung M F Ashame S Chen T H MacRae P Sorgeloos P Bossier 《Journal of fish diseases》2009,32(8):675-685
Among their numerous physiological effects, heat shock proteins (Hsps) are potent immunomodulators, a characteristic reflecting their potential as therapeutic agents and which led to their application in combating infection. As an example, the up-regulation of endogenous Hsp70 in the branchiopod crustacean Artemia franciscana (Kellogg) is concurrent with shielding against bacterial infection. To better understand this protective mechanism, gnotobiotic Artemia were fed with Escherichia coli treated to over-produce different prokaryotic Hsps. This was shown to increase larval resistance to experimental Vibrio campbellii exposure. Immunoprobing of Western blots showed that the enhanced resistance to V. campbellii correlated with DnaK production in E coli . A definitive role for DnaK was then demonstrated by feeding Artemia larvae with transformed bacteria over-producing only this protein, although other Hsps such as DnaJ and grpE also provided tolerance against Vibrio infection. Feeding of bacteria synthesizing selected Hsps is therefore suggested as an alternative to antibiotic use as a means of enhancing resistance of Artemia larvae to bacterial infection, which may have potential applications in aquaculture. 相似文献