全文获取类型
收费全文 | 5899篇 |
免费 | 331篇 |
国内免费 | 7篇 |
专业分类
林业 | 290篇 |
农学 | 255篇 |
基础科学 | 16篇 |
1049篇 | |
综合类 | 747篇 |
农作物 | 595篇 |
水产渔业 | 494篇 |
畜牧兽医 | 2286篇 |
园艺 | 75篇 |
植物保护 | 430篇 |
出版年
2023年 | 35篇 |
2022年 | 106篇 |
2021年 | 135篇 |
2020年 | 108篇 |
2019年 | 115篇 |
2018年 | 142篇 |
2017年 | 169篇 |
2016年 | 191篇 |
2015年 | 171篇 |
2014年 | 207篇 |
2013年 | 303篇 |
2012年 | 372篇 |
2011年 | 435篇 |
2010年 | 244篇 |
2009年 | 247篇 |
2008年 | 337篇 |
2007年 | 329篇 |
2006年 | 287篇 |
2005年 | 260篇 |
2004年 | 241篇 |
2003年 | 195篇 |
2002年 | 212篇 |
2001年 | 150篇 |
2000年 | 120篇 |
1999年 | 84篇 |
1998年 | 45篇 |
1997年 | 30篇 |
1996年 | 40篇 |
1995年 | 33篇 |
1994年 | 25篇 |
1993年 | 41篇 |
1992年 | 39篇 |
1991年 | 37篇 |
1990年 | 44篇 |
1989年 | 51篇 |
1988年 | 38篇 |
1987年 | 53篇 |
1986年 | 25篇 |
1985年 | 41篇 |
1984年 | 27篇 |
1983年 | 32篇 |
1981年 | 30篇 |
1980年 | 24篇 |
1979年 | 22篇 |
1978年 | 26篇 |
1977年 | 23篇 |
1976年 | 34篇 |
1974年 | 22篇 |
1973年 | 23篇 |
1972年 | 24篇 |
排序方式: 共有6237条查询结果,搜索用时 0 毫秒
991.
992.
M. Her D.‐H. Cho S.‐I. Kang J.‐S. Lim H.‐J. Kim Y.‐S. Cho I.‐Y. Hwang T. Lee S.‐C. Jung H.‐S. Yoo 《Zoonoses and public health》2010,57(3):155-161
Seven of 18 elk on a deer farm were found by the official Rose‐Bengal agglutination test (RBT) and tube agglutination test to be brucellosis reactors/suspects. Evaluation with the competitive ELISA (C‐ELISA) and the fluorescence polarization assay (FPA) tests revealed that six and five sera were positive respectively. The seven reactors/ suspects were slaughtered and their blood and tissues were collected. Brucella species could be isolated from three of the slaughtered animals, with nine isolates being obtained from the popliteal, supramammary and submandibular lymph nodes, vaginal discharge, mammary tissue and spleen. Brucella genus‐specific PCR based on 16S rRNA and AMOS‐PCR, which is specific for differential Brucella species, revealed that all nine isolates were Brucella abortus. These nine were further confirmed to be B. abortus biovar 1 by classical biotyping scheme assays. This is the first report of an outbreak of brucellosis in domestic elk in Korea. Our observations suggest that deer should be included in the routine Brucella surveillance programme for the effective control and prevention of brucellosis in Korea. 相似文献
993.
Hyun-Jung Chung Seung-Eun Lee Jung-Ah Han Seung-Taik Lim 《Journal of Cereal Science》2010,52(3):496-501
Waxy corn starch was modified by dry heating (130 °C, 2 h) in the presence of octenyl succinic acid (OSA) at different pHs (4, 6, and 8), and the physicochemical properties of the modified starch were evaluated. The dry-heated octenyl succinylated (DH-OS) starch was also evaluated as a partial fat substitute in a muffin. Dry heating of starch under a more acidic condition resulted in lower degree of polymerization (DPn) but lower degree of substitution (DS). The pasting viscosity of the DH-OS starch prepared under basic conditions was higher than that of the unheated counterparts, whereas that under acidic conditions was lower. It was because the substitution favored basic conditions, and thermal degradation was accelerated by acids. The gelatinization characteristic was not significantly altered by OSA substitution and dry heating. The muffin containing the DH-OS starch had a higher specific volume and a softer texture than the muffin containing maltodextrin. Among the DH-OS starches tested, the starch prepared under acidic conditions produced muffins that had a greater volume, which was most likely due to its low molecular size. The muffin prepared with DH-OS starch at pH 6 was the softest in texture and had characteristics that were relatively close to the full-fat muffin. 相似文献
994.
Yu Cheng Zhu Jian‐Zhong Sun Lily Li Luo Xiaofen Fanny Liu Karmen Christeen Lee Eldon J Mallette Craig A Abel 《Pest management science》2010,66(6):612-620
BACKGROUND: Coptotermes formosanus Shiraki was accidentally introduced into the United States from Asia. The introduction of the pest has brought significant economic consequences. During the past decade, Mississippi has become a significantly infested state, partly due to the proximity to coastal port cities such as New Orleans. This study was initiated to investigate the origin and infestation route of C. formosanus in southern Mississippi. RESULTS: Twenty‐eight colonies (21 colonies from Mississippi, six from Louisiana, one from China) were collected. Sequencing and analysis of 112 sequences revealed 15 haplotypes of cytochrome oxidase subunit II (COII) gene in the world. Two haplotypes of COII were identified in Mississippi. In addition, specific primers were designed and tested differentially to amplify characteristic fragments for verifying and surveying different genotypes of C. formosanus in the future. CONCLUSION: Of the two haplotypes identified in Mississippi, the GA group was identical to those reported previously in Georgia, Louisiana, Alabama and other infested states. The second haplotype, the AT group, was identified for the first time in southeastern United States. Sequence identity of the AT‐group C. formosanus with those reported mainly in southeastern Asian countries provided evidence of at least two introductions of C. formosanus into the United States. Copyright © 2010 Society of Chemical Industry 相似文献
995.
Hyeok Ran Kwon Gyung Ja Choi Yong Ho Choi Kyoung Soo Jang Nack‐Do Sung Mun Seong Kang Yilseong Moon Seung Kyu Lee Jin‐Cheol Kim 《Pest management science》2010,66(6):634-639
BACKGROUND: Pine wilt disease (PWD) is very complex and has been reported to be caused by pine wood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle, and its accompanying bacteria. However, there is no report on the control of PWD by antibacterial agent. The present study was performed to investigate disease control efficacy of antibacterial agents against PWD. RESULTS: Among six antibacterial antibiotics tested, oxolinic acid (OA) showed the strongest antibacterial activity against five bacteria isolated from three strains of pine wood nematode. In in vivo assay, it effectively suppressed the development of PWD in three‐year‐old seedlings of Pinus densiflora Sieb. & Zucc.; it showed 71% control when injected at 3 mg per seedling. A mixture of OA and the nematicidal agent abamectin (Ab) showed higher disease control efficacy against PWD than either OA or Ab alone. In addition, OA alone and a mixture of OA and Ab also controlled PWD in approximately 20‐year‐old pine trees under field conditions. CONCLUSION: This is the first report on the suppression of PWD by OA. The result strongly indicates that PWD could be controlled by antibacterial antibiotic alone and a combination of antibacterial and nematicidal agents. Copyright © 2010 Society of Chemical Industry 相似文献
996.
影响青海细毛羊早期性状非遗传因素的研究 总被引:1,自引:0,他引:1
以年度(YEAR)、场(HERD)、性别(SEX)、母亲年龄(DAGE)作为固定效应,应用方差分析方法,系统分析了2005~2010年间青海细毛羊早期性能记录。结果显示,年度、场对青海细毛羊早期性状均有显著影响,母羊年龄对初生重、断奶重、周岁剪毛前体重有显著影响,性别对初生重,断奶重,周岁剪毛前体重、周岁产毛量、羊毛长度、羊毛细度影响显著;所有性状均随母亲年龄的增加呈上升趋势,研究结果将为优化群体周转结构,建立青海细毛羊早期生产性状遗传评价模型提供科学依据,最终为该品种羊的早期选种奠定基础。 相似文献
997.
Jundae Lee Jae Bok Yoon Jung-Heon Han Won Phil Lee Sang Hoon Kim Hyo Guen Park 《Euphytica》2010,173(1):55-61
Genic male sterility (GMS) has long been used as a tool for hybrid seed production in chili pepper (Capsicum annuum L.). We developed DNA markers linked to the GMS ms
3
gene in a segregating population using bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP)
techniques. The segregating population was subjected to BSA-AFLP with 512 primer combinations. Three AFLP markers (Eagg/Mccc276, Eagc/Mctt178, and Ecag/Mtgc204) were identified as tightly linked to the ms
3
locus. Among them, we converted the AFLP marker Ecag/Mtgc204 to the cleavage amplified polymorphic sequence (CAPS) marker, named GMS3-CAPS, based on sequencing analysis of internal and
flanking regions for the markers between male-fertile and sterile plants. This marker will be useful for pepper breeding using
the GMS system. 相似文献
998.
999.
1000.
Yasuyuki Matsushita In-Cheol Jang Takanori Imai Kazuhiko Fukushima Seung-Cheol Lee 《Journal of Wood Science》2010,56(5):418-421
A detailed chemical investigation of the extractives of the blackened heartwood of Diospyros kaki was carried out to understand their chemical characteristics and to obtain chemotaxonomic information. Three novel naphthalene
derivatives were isolated, i.e., 4-hydroxy-5,6-dimethoxy-2-naphthaldehyde (1), 5,6,8-trimethoxy-3-methyl-1-naphthol (2), and 4,8-dihydroxy-5-methoxy-2-naphthaldehyde (3), in addition to two previously reported 2-naphthaldehydes: 4-hydroxy-5,8-dimethoxy-2-naphthaldehyde (4) and 4-hydroxy-5-methoxy-2-naphthaldehyde (5) Their structures were identified by 1D and 2D nuclear magnetic resonance spectroscopy, as well as by high-resolution mass
spectrometry. 相似文献