全文获取类型
收费全文 | 659篇 |
免费 | 33篇 |
专业分类
林业 | 32篇 |
农学 | 20篇 |
基础科学 | 1篇 |
112篇 | |
综合类 | 50篇 |
农作物 | 101篇 |
水产渔业 | 52篇 |
畜牧兽医 | 237篇 |
园艺 | 8篇 |
植物保护 | 79篇 |
出版年
2023年 | 2篇 |
2022年 | 13篇 |
2021年 | 18篇 |
2020年 | 21篇 |
2019年 | 18篇 |
2018年 | 16篇 |
2017年 | 25篇 |
2016年 | 21篇 |
2015年 | 20篇 |
2014年 | 33篇 |
2013年 | 38篇 |
2012年 | 40篇 |
2011年 | 49篇 |
2010年 | 30篇 |
2009年 | 22篇 |
2008年 | 42篇 |
2007年 | 37篇 |
2006年 | 33篇 |
2005年 | 31篇 |
2004年 | 33篇 |
2003年 | 20篇 |
2002年 | 19篇 |
2001年 | 11篇 |
2000年 | 16篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 3篇 |
1964年 | 2篇 |
1963年 | 2篇 |
1959年 | 1篇 |
1956年 | 1篇 |
1948年 | 1篇 |
1947年 | 1篇 |
1938年 | 1篇 |
排序方式: 共有692条查询结果,搜索用时 312 毫秒
621.
Genetics and mapping of quantitative traits for nodule number, weight, and size in soybean (Glycine max L.[Merr.]) 总被引:1,自引:0,他引:1
Sadal Hwang Jeffery D. Ray Perry B. Cregan C. Andy King Marilynn K. Davies Larry C. Purcell 《Euphytica》2014,195(3):419-434
Soybean research has found that nodule traits, especially nodule biomass, are associated with N2 fixation ability. Two genotypes, differing in nodule number per plant and individual nodule weight, KS4895 and Jackson, were mated to create 17 F3- and 80 F5-derived RILs. The population was mapped with 664 informative markers with an average distance of less than 20 cM between adjacent markers. Nodule traits were evaluated in 3-year field trials. Broad-sense heritability for nodule number (no. plant?1), individual nodule dry weight (mg nodule?1), individual nodule size (mm nodule?1), and total nodule dry weight (g plant?1) was 0.41, 0.42, 0.45, and 0.27, respectively. Nodule number was negatively correlated with individual nodule weight and size. Nodule number, individual nodule weight, and size are major components which likely contributed to increased total nodule weight per plant. Composite interval mapping (CIM) identified eight QTLs for nodule number with R2 values ranging from 0.14 to 0.20. Multiple interval mapping (MIM) identified two QTLs for nodule number, one of which was located close to the QTL identified with CIM. Six QTLs for individual nodule weight were detected with CIM, and one QTL was identified with MIM. For nodule size, CIM identified seven QTLs with R2 values ranging from 0.14 to 0.27. Five QTLs for total nodule weight were detected with CIM, one of which was located close to a QTL identified with MIM. These results document the first QTL information on nodule traits in soybean from field experiments utilizing a dense, complete linkage map. 相似文献
622.
Jin-Ah Kim Sang-Woo Lee Gil-Soon Hwang Soon-Jin Hwang Chulgoo Kim Kyung-Jin An 《Paddy and Water Environment》2016,14(2):299-312
Urban land use can adversely affect the water quality of adjacent streams through interactions at the edges of the two ecosystems. From a landscape ecological perspective, edges control the flow rate of materials between two adjacent systems. Based on the rationale that the streamline complexity formed between land uses and water bodies may function in this manner, we investigated the potential role of streamline complexity in the relationship between stream ecological communities and urban land use in Korea. Various indices of biological indicators including the diatom assemblage index for organic pollution, the trophic diatom index, the Korean saprobic index, and the index of biotic integrity were applied at 80 sampling sites in the Nakdong River system. We computed the fractal dimensions of the streamlines within 1-km buffers and the proportion of urban land use in the watershed within 5-km buffers around the sampling sites. A moderation model was adopted to investigate the role of streamline complexity in the relationship between urban land use and the biological indices of ecological communities. A comparison between a simple geometry regression model and complex geometry models indicated that streamline complexity may moderate the adverse impacts of urban land use on ecological communities in streams. The moderating effect of streamline complexity was particularly significant for assemblages of macroinvertebrates and fishes. Therefore, to enhance the ecological integrity of streams, we strongly recommend considering streamline complexity when restoring channelized streams in developed areas. 相似文献
623.
Hsien-Feng Kung Yi-Chen Lee Ya-Ling Huang Chun-Yung Huang Chiu-Chu Hwang Yung-Hsiang Tsai 《International Aquatic Research》2016,8(3):217-226
Histamine is the main causative agent of scombroid poisoning. However, unlike scombroid fish, histamine poisoning due to consumption of flying fish has never been reported. In this study, the white muscle of flying fish had high levels of free histidine at approximately 423.9 mg/100 g, and was inoculated with Staphylococcus xylosus Q2 isolated from dried flying fish at 5.0 log CFU/g and stored at ?20 to 35°C to investigate histamine-related quality. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 25 and 35°C within 12 h as well as stored at 15°C within 48 h. However, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C or below. Once the frozen flying fish samples stored at ?20°C for 2 months were thawed and stored at 25°C after 24 h, histamine started to accumulate rapidly (>50 mg/100 g of fish). Therefore, flying fish muscle was a good substrate for histamine formation by bacterial histidine decarboxylation at elevated temperatures (>15°C) when it is contaminated with S. xylosus. In conclusion, since the improperly contaminated flying fish muscle with S. xylosus could lead to production of hazardous levels of histamine over time when stored at temperatures >15°C, the flying fish should be stored below 4 °C or below to control proliferation of S. xylosus, and TVBN and histamine production. 相似文献
624.
625.
Ana Clariza Samayoa Kyung San Choi Yun-Shiuan Wang Shaw-Yhi Hwang Yu-Bing Huang Jeong Joon Ahn 《Phytoparasitica》2018,46(3):365-376
The oriental fruit fly, Bactrocera dorsalis (Hendel), is a major polyphagous insect pest with a worldwide distribution. The effects of temperature on stage-specific development in B. dorsalis were investigated at eight constant temperatures (13.0 °C, 14.4 °C, 16.2 °C, 19.5 °C, 23.8 °C, 27.7 °C, 31.8 °C and 34.8 °C). B. dorsalis developed successfully from the egg stage to the adult stage at all the tested temperatures, except at the lowest temperatures (13.0 °C and 14.4 °C). Stage-specific lower developmental thresholds and thermal constants were determined using linear regression. The lower and higher temperature threshold (TL and TH, respectively) were estimated using the Sharpe-Schoolfield-Ikemoto model. The lower developmental threshold and thermal constant from egg to adult emergence were 9.8 °C and 325.5 degree-days, respectively. The intrinsic optimum temperatures of the egg, larval, pupal and egg to pupal stage were 20.7 °C, 21.8 °C, 21.1 °C, and 22.4 °C, respectively. The temperature range of the B. dorsalis total immature stage from TL to TH was 20.4 °C (13.8 °C - 34.2 °C). The stage-specific developmental completion of B. dorsalis was determined using a two-parameter Weibull function. The daily adult emergence frequency of B. dorsalis was estimated in relation to adult age and temperature using non-linear developmental rate functions and the Weibull function. The date of cumulative 50% adult emergence estimated using non-linear functions was approximately one day earlier than the experimentally observed date. Thermal performance was compared among B. dorsalis populations from different locations. 相似文献
626.
A molecular marker for the specific detection of new pathotype 5‐like strains of Plasmodiophora brassicae in canola
下载免费PDF全文
![点击此处可从《Plant pathology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Q. Zhou S. F. Hwang S. E. Strelkov R. Fredua‐Agyeman V. P. Manolii 《Plant pathology》2018,67(7):1582-1588
Clubroot of crucifers, caused by Plasmodiophora brassicae, is managed in canola (Brassica napus) by the deployment of resistant cultivars. Recently, however, new strains of P. brassicae have been detected in Alberta, Canada, that can overcome this resistance. Some of these strains are classified as pathotype 5 on the differential system of Williams, but are distinguished by their ability to overcome host resistance. In order to expedite the identification of these new pathotype 5‐like strains, three primer sets were developed based on the 18S‐ITS region of the pathogen. With primers P5XF3 and P5XR3, a 127 bp product was amplified from all new pathotype 5‐like strains following optimized PCR analysis. A TaqMan probe‐based quantitative assay was also developed. These protocols could be used to detect as little as 0.5 pg P. brassicae DNA, and as few as 104 mL?1 pathogen resting spores; infection of host tissues could be detected as soon as 4 days after inoculation. The PCR and qPCR assays described in this study represent useful tools for the rapid and reliable diagnosis and quantification of new pathotype 5‐like strains of P. brassicae. 相似文献
627.
Sung Chul Park Jung-Ho Lee Ji-Yeon Hwang Oh-Seok Kwon Lijuan Liao Dong-Chan Oh Ki-Bong Oh Jongheon Shin 《Marine drugs》2021,19(8)
Ochraceopetalin (1), a mixed-biogenetic salt compound and its component 2 were isolated from the culture broths of a marine-derived fungus, Aspergillus ochraceopetaliformis. Based on combined spectroscopic and chemical analyses, the structure of 1 was determined to be a sulfonated diphenylether-aminol-amino acid ester guanidinium salt of an unprecedented structural class, while 2 was determined to be the corresponding sulfonated diphenylether. Ochraceopetaguanidine (3), the other guanidine-bearing aminol amino acid ester component, was also prepared and structurally elucidated. Compound 1 exhibited significant cytotoxicity against K562 and A549 cells. 相似文献
628.
A new germacrane-type sesquiterpenoid, menelloide E (1), and a new cembrane-type diterpenoid, lobocrassin F (2), were isolated from the octocorals Menella sp. and Lobophytum crassum, respectively. The structures of terpenoids 1 and 2 were determined by spectroscopic and chemical methods and compound 2 was found to display a significant inhibitory effect on the release of elastase by human neutrophils. 相似文献
629.
Chemical investigation of Junceella juncea has resulted in the isolation of three new briaranes designated juncenolides M-O (1-3). The structures of these compounds were determined by spectroscopic analysis including 2D-NMR (COSY, HMBC and NOESY) and HRMS. Compound 1 is a new chlorinated briarane while compound 3 contains a rare methyl ester at C-16. The anti-inflammatory activities tested on superoxide anion generation and elastase release by human neutrophils in response to FMLP/CB were evaluated. 相似文献
630.
Jae Young Cho Jae Gwon Son Chang Hoon Song Seon Ah Hwang Young Min Lee Se Young Jeong Byung Yeoup Chung 《Paddy and Water Environment》2008,6(3):263-273
This study was conducted in an attempt to determine the proper nitrogen and phosphorus application levels, nitrogen split
application ratio, and application method for environmental-friendly rice production in a salt-affected rice paddy field,
which was located in the Saemangeum reclaimed tidal belt on the western coast of South Korea, between April 1, 2003 and October
10, 2004. All treatments were replicated three times in a randomized block design (5 m × 4 m plot) with 11 treatments (total
33 plots). We designed three treatments for the evaluation of reasonable application levels of nitrogen and phosphorus fertilizers
(A1–A3); five treatments to evaluate the nitrogen split application system (T1–T5); and three treatments to determine the
proper application for chemical fertilizer (M1–M3). There was no significant difference of amylose and protein content among
the application levels, application methods, and nitrogen split application ratios (P < 0.05). No significant differences in grain yield and yield components of rice were observed among the different application
levels, application methods, and nitrogen split application ratios (P < 0.05). In order to save labor in agricultural households, preserve or enhance the grain quality of rice, and reduce nutrient
losses, we determined that the optimum application level of nitrogen fertilizer was 140 kg ha−1; the application split ratio of nitrogen fertilizer at four different periods was 40% for basal fertilization, 20% for maximum
tilling stage, 30% for the panicle formation stage, and 10% for the booting stage; and the best application methods were deep
layer application and whole layer application. 相似文献