全文获取类型
收费全文 | 808篇 |
免费 | 49篇 |
国内免费 | 4篇 |
专业分类
林业 | 36篇 |
农学 | 23篇 |
基础科学 | 1篇 |
207篇 | |
综合类 | 86篇 |
农作物 | 123篇 |
水产渔业 | 58篇 |
畜牧兽医 | 263篇 |
园艺 | 13篇 |
植物保护 | 51篇 |
出版年
2023年 | 3篇 |
2022年 | 18篇 |
2021年 | 24篇 |
2020年 | 16篇 |
2019年 | 25篇 |
2018年 | 17篇 |
2017年 | 20篇 |
2016年 | 29篇 |
2015年 | 34篇 |
2014年 | 26篇 |
2013年 | 48篇 |
2012年 | 58篇 |
2011年 | 73篇 |
2010年 | 27篇 |
2009年 | 18篇 |
2008年 | 44篇 |
2007年 | 41篇 |
2006年 | 40篇 |
2005年 | 32篇 |
2004年 | 31篇 |
2003年 | 31篇 |
2002年 | 26篇 |
2001年 | 23篇 |
2000年 | 22篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 9篇 |
1989年 | 18篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1972年 | 2篇 |
1969年 | 4篇 |
1966年 | 1篇 |
1965年 | 2篇 |
1964年 | 3篇 |
1963年 | 1篇 |
排序方式: 共有861条查询结果,搜索用时 16 毫秒
161.
Jeong Ho Song Tae Jo Kang Young Don Cho Sun Hyoung Lee Jeong Soo Kim 《Fibers and Polymers》2006,7(3):217-222
Propargyl alcohol was coupled to 2,4-hexadiyne-1,6-diol (HDD) and crystallized in the process of ultraviolet irradiation-induced
topochemical polymerization. The HDD polymer crystals were used as one component in the fabrication of organic photovoltaic
cells, in combination with fullerene as the electron acceptor. The various structures of the produced photovoltaic cells included
bilayer, trilayer, and bulk heterojunction structures. Their photovoltaic properties were analyzed in relation to crystal
structure, electrochemical properties, and band structure of the HDD polydiacetylene polymers. 相似文献
162.
Summary The activities of lipolytic acyl-hydrolases (LAH) and lipoxygenases (LOX) were compared in stored tubers of potato cultivars
resistant (Acresta, Eba, Pentland Envoy) and susceptible (Kastor, Pana, Tasso) to post-wounding autolysis. In most cultivars,
LAH activities had reached a maximum by the end of December but in cv. Kastor activity continued to increase throughout the
storage period. LOX activities increased during most of the storage period except in cv. Tasso. The level of the fatty acid
hydroperoxides, assumed from determinations of the malonaldehyde level, also increased during storage.
This work was supported by Project CPBP 05.02.2.10 financed by the Polish Academy of Science. 相似文献
163.
Kim Soon-Oh Jeong Jin Young Lee Woo-Chun Yun Seong-Taek Jo Ho Young 《Journal of Soils and Sediments》2021,21(8):2755-2769
Journal of Soils and Sediments - Electrokinetic (EK) soil remediation is significantly affected by the electrode configurations. Therefore, this study was conducted to compare the performance of... 相似文献
164.
Ho Cheon Lee Young Gyu Jeong Byung Gil Min Won Seok Lyoo Sang Cheol Lee 《Fibers and Polymers》2009,10(5):636-642
We prepared a series of polyurethane(PU)/chitosan composite foams with different chitosan content of 5∼20 wt% and investigated
their adsorption performance of acid dye (Acid Violet 48) in aqueous solutions with various dye concentrations and pH values.
It was observed that PU/chitosan composite foams exhibited well-developed open cell structures. Dye adsorption capacities
of the composite foams increased with the increment of chitosan content in composite foams, because amine groups of chitosan
serve as the binding sites for sulfonic ions of acid dyes in aqueous solutions. In addition, dye adsorption capacities of
composite foams were found to increase with decreasing the pH value, which stems from the fact that the enhanced chemisorption
between protonated amine groups of chitosan and sulfonic ions of acid dye is available in acidic solutions. The dye adsoption
kinetics and equilibrium isotherm of the composite foams were well described with the pseudo-second order kinetic model and
Langmuir isotherm model, respectively. The maximum adsorption capacity (q
max) for the PU/chitosan composite foams with 20 wt% chitosan content is evaluated to be ca. 30 mg/g. 相似文献
165.
Electroacupuncture-induced neural activation detected by use of manganese-enhanced functional magnetic resonance imaging in rabbits 总被引:12,自引:0,他引:12
Chiu JH Cheng HC Tai CH Hsieh JC Yeh TC Cheng H Lin JG Ho LT 《American journal of veterinary research》2001,62(2):178-182
OBJECTIVE: To investigate the effects of acupuncture on neural activity detected by use of manganese-enhanced functional magnetic resonance imaging (fMRI) and elucidate the relationship between somatic acupoint stimulation and brain activation. ANIMALS: 40 New Zealand White rabbits. PROCEDURE: Manganese-enhanced fMRI was performed in anesthetized rabbits manipulated with electroacupuncture (EA) on Zusanli (ST-36) and Yanglingquan (GB-34) acupoints. Image acquisition was performed on a 1.5T superconductive clinical scanner with a circular polarized extremity coil. T1-weighted images were acquired sequentially as follows: baseline, after mannitol injection, after manganese infusion, and 5 and 20 minutes after initiation of EA. RESULTS: Changes in focal neural activity were detected by use of manganese-enhanced fMRI. Stimulation on Zusanli (ST-36) for 5 minutes resulted in activation of the hippocampus, whereas stimulation on Yanglingquan (GB-34) resulted in activation of the hypothalamus, insula, and motor cortex. Activation became less specific after 20 minutes of EA. Furthermore, stimulation on ipsilateral acupoints led to bilateral brain activation. CONCLUSIONS AND CLINICAL RELEVANCE: Each acupoint has a corresponding cerebral linkage, and stimulation on these points resulted in time-dependent neural activation. Understanding the linkage between peripheral acupoint stimulation and central neural pathways may provide a useful guide for clinical applications of acupuncture. 相似文献
166.
Ye-Ji Kim Jei Ha Lee Seung-Hyun Jung Ki Hyun Kim Chang-Hoon Choi Seonmi Jo Dong Ho Woo 《Marine drugs》2022,20(5)
Discovering new drug candidates with high efficacy and few side effects is a major challenge in new drug development. The two evolutionarily related peptides oxytocin (OXT) and arginine vasopressin (AVP) are known to be associated with a variety of physiological and psychological processes via the association of OXT with three types of AVP receptors. Over decades, many synthetic analogs of these peptides have been designed and tested for therapeutic applications; however, only a few studies of their natural analogs have been performed. In this study, we investigated the bioactivity and usefulness of two natural OXT/AVP analogs that originate from the marine invertebrate Octopus vulgaris, named octopressin (OTP) and cephalotocin (CPT). By measuring the intracellular Ca2+ or cyclic AMP increase in each OXT/AVP receptor subtype–overexpressing cell, we found that CPT, but not OTP, acts as a selective agonist of human AVP type 1b and 2 receptors. This behavior is reminiscent of desmopressin, the most widely prescribed antidiuretic drug in the world. Similar to the case for desmopressin, a single intravenous tail injection of CPT into Sprague-Dawley rats reduced urine output and increased urinary osmolality. In conclusion, we suggest that CPT has a significant antidiuretic effect and that CPT might be beneficial for treating urological conditions such as nocturia, enuresis, and diabetes insipidus. 相似文献
167.
Hyeshin Hwang Younghye Ro Hyunkyoung Lee Jihyeon Kim Kyunghyun Lee Eun-Jin Choi You-Chan Bae ByungJae So Dohoon Kwon Ho Kim Inhyung Lee 《Journal of veterinary science (Suw?n-si, Korea)》2022,23(5)
BackgroundSince 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015–2016 identified Setaria digitata as the causative agent.ObjectivesThis study is an epidemiological investigation to find out risk factors related to the rapid increase in hindlimb ataxia of horses due to aberrant parasites in South Korea.MethodsAn epidemiological investigation was conducted on 155 cohabiting horses in 41 horse ranches where the disease occurred. The surrounding environment was investigated at the disease-causing horse ranches (n = 41) and 20, randomly selected, non-infected ranches.ResultsHindlimb ataxia was confirmed in nine cohabiting horses; this was presumed to be caused by ectopic parasitism. Environments that mosquitoes inhabit, such as paddy fields within 2 km and less than 0.5 km from a river, had the greatest association with disease occurrence.ConclusionsMost horse ranches in South Korea are situated in favorable environments for mosquitoes. Moreover, the number of mosquitoes in the country has increased since 2013 due to climate change. Additional research is required; however, these data show that it is necessary to establish guidelines for the use of anthelmintic agents based on local factors in South Korea and disinfection of the environment to prevent disease outbreaks. 相似文献
168.
169.
170.
为了探寻不同发育期朝鲜球坚蚧的有效防治新措施,根据朝鲜球坚蚧不同发育阶段的形态特征和生物学习性,对不同龄期的若虫采取刮皮涂干、树干注射和常规喷雾等措施进行防治.试验结果表明;在施药方法上,刮皮涂干和常规喷雾是最为适用的;在药效方面,在1龄若虫期喷雾施用的几种药剂中醋盐合剂对1龄若虫的喷洒防效达到了90%以上.通过施用脱叶剂处理叶片的方法来防治2龄若虫,试验所设3种浓度的脱叶剂均能间接起到防治作用,其效果均达到了95%以上.在3龄若虫期喷雾施用的几种药剂中95%酒精合剂的喷洒防效达到了90%以上.涂干防治3龄若虫期供试的几种药剂中,20%吡虫啉可溶性液剂1∶10的稀释液防效达到了90%以上. 相似文献