全文获取类型
收费全文 | 2113篇 |
免费 | 107篇 |
国内免费 | 1篇 |
专业分类
林业 | 109篇 |
农学 | 132篇 |
基础科学 | 3篇 |
372篇 | |
综合类 | 146篇 |
农作物 | 274篇 |
水产渔业 | 186篇 |
畜牧兽医 | 842篇 |
园艺 | 33篇 |
植物保护 | 124篇 |
出版年
2023年 | 14篇 |
2022年 | 30篇 |
2021年 | 52篇 |
2020年 | 34篇 |
2019年 | 40篇 |
2018年 | 53篇 |
2017年 | 64篇 |
2016年 | 61篇 |
2015年 | 64篇 |
2014年 | 92篇 |
2013年 | 122篇 |
2012年 | 162篇 |
2011年 | 170篇 |
2010年 | 111篇 |
2009年 | 116篇 |
2008年 | 141篇 |
2007年 | 137篇 |
2006年 | 151篇 |
2005年 | 85篇 |
2004年 | 84篇 |
2003年 | 78篇 |
2002年 | 77篇 |
2001年 | 67篇 |
2000年 | 38篇 |
1999年 | 26篇 |
1998年 | 12篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 10篇 |
1991年 | 3篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1985年 | 6篇 |
1981年 | 3篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 7篇 |
1973年 | 10篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1968年 | 2篇 |
1966年 | 4篇 |
1949年 | 2篇 |
1929年 | 2篇 |
排序方式: 共有2221条查询结果,搜索用时 328 毫秒
981.
CH Choresca OJ Koo SG Hong HJ Oh DK Gomez JH Kim BC Lee SC Park 《Reproduction in domestic animals》2010,45(5):e73-e77
Several studies have previously been conducted regarding cell cycle synchronization in mammalian somatic cells. However, limited work has been performed on the control of cell cycle stages in the somatic cells of fish. The aim of this study was to determine the cell cycle arresting effects of several dimethyl sulfoxide (DMSO) concentrations for different times on different cell cycle stages of goldfish caudal fin‐derived fibroblasts. Results demonstrated that the cycling cells or control group (68.29%) yields significantly higher (p < 0.05) arrest in G0/G1 phase compared with the group treated for 24 h with different concentrations (0.5%, 1.0% or 1.5%) of DMSO (64.88%, 65.70%, 64.22% respectively). The cell cycle synchronization in the treatment of cells with 1.0% DMSO at 48 h (81.14%) was significantly higher than that in the groups treated for 24 h (76.82%) and the control group (77.90%). Observations showed that treatment of DMSO resulted in an increase in the proportion of cells at G0/G1 phase for 48 h of culture. However, high levels of apoptotic cells can be detected after 48 h of culture treated with 1% concentration of DMSO. 相似文献
982.
Judging from the ecotypic variability in Arabidopsis thaliana L., Columbia-0 (Col-0) appears to be less tolerant to cadmium (Cd) than the Wassilewskija (Ws) ecotype that possesses the full-length Heavy Metal ATPase3 (HMA3) cDNA. In this study, the Ws and Col-0 were tested to determine toxic metal response between Ws and Col-0 due to AtHMA3 point mutation and/or other factors. The growth inhibition of Col-0 mediated by Cd and zinc (Zn) was more serious than the inhibition of Ws, while no significant difference was evident by lead (Pb) and cobalt (Co). In the presence of Cd stress, chlorosis in leaves of Col-0 was more serious than the Ws ecotype. When grown under hydroponic culture containing 500?µM Zn, leaves of Col-0 showed a remarkable increase in the anthocyanin content in a dose-dependent manner and the expression of genes encoding enzymes involved in anthocyanin synthesis in the leaves. The rate of root-to-shoot translocation of Cd and Zn in the Col-0 was 2 times higher when compared with the Ws, whereas roots of the Col-0 accumulated 2 times lower Cd and Zn concentrations than those of the Ws. Real-time polymerase chain reaction (PCR) analyses indicated that not only the alteration of the expression of HMA3 but also of the HMA4 was responsible for the root-to-shoot translocation of toxic metals. The results demonstrate that the Col-0 is readily translocating Cd and Zn to the aerial parts but not the Ws, thereby induce the alteration of phenotype in leaf color. 相似文献
983.
Sundaram J Park B Hinton A Yoon SC Windham WR Lawrence KC 《Journal of agricultural and food chemistry》2012,60(4):991-1004
Fourier transform infrared spectroscopy (FT-IR) was used to detect Salmonella Typhimurium and Salmonella Enteritidis food-borne bacteria and to distinguish between live and dead cells of both serotypes. Bacteria cells were prepared in 10(8) cfu/mL concentration, and 1 mL of each bacterium was loaded individually on the ZnSe attenuated total reflection (ATR) crystal surface (45° ZnSe, 10 bounces, and 48 mm × 5 mm effective area of analysis on the crystal) and scanned for spectral data collection from 4000 to 650 cm(-1) wavenumber. Analysis of spectral signatures of Salmonella isolates was conducted using principal component analysis (PCA). Spectral data were divided into three regions such as 900-1300, 1300-1800, and 3000-2200 cm(-1) based on their spectral signatures. PCA models were developed to differentiate the serotypes and live and dead cells of each serotype. Maximum classification accuracy of 100% was obtained for serotype differentiation as well as for live and dead cells differentiation. Soft independent modeling of class analogy (SIMCA) analysis was carried out on the PCA model and applied to validation sample sets. It gave a predicted classification accuracy of 100% for both the serotypes and its live and dead cells differentiation. The Mahalanobis distance calculated in three different spectral regions showed maximum distance for the 1800-1300 cm(-1) region, followed by the 3000-2200 cm(-1) region, and then by the 1300-900 cm(-1) region. It showed that both of the serotypes have maximum differences in their nucleic acids, DNA/RNA backbone structures, protein, and amide I and amide II bands. 相似文献
984.
Park HG Cho HT Song MC Kim SB Kwon EG Choi NJ Kim YJ 《Journal of agricultural and food chemistry》2012,60(12):3204-3210
This study was performed to characterize natural CLnA isomer production by Bifidobacterium breve LMC520 of human origin in comparison to conjugated linoleic acid (CLA) production. B. breve LMC520 was found to be highly active in terms of CLnA production, of which the major portion was identified as cis-9,trans-11,cis-15 CLnA isomer by GC-MS and NMR analysis. B. breve LMC520 was incubated for 48 h using MRS medium (containing 0.05% L-cysteine · HCl) under different environmental conditions such as atmosphere, pH, and substrate concentration. The high conversion rate of α-linolenic acid (α-LNA) to CLnA (99%) was retained up to 2 mM α-LNA, and the production was proportionally increased nearly 7-fold with 8 mM by the 6 h of incubation under anaerobic conditions at a wide range of pH values (between 5 and 9). When α-LNA was compared with linoleic acid (LA) as a substrate for isomerization by B. breve LMC520, the conversion of α-LNA was higher than that of LA. These results demonstrated that specific CLnA isomer could be produced through active bacterial conversion at an optimized condition. Because many conjugated octadecatrienoic acids in nature are shown to play many positive roles, the noble isomer found in this study has potential as a functional source. 相似文献
985.
Lee ES Park SH Kim MS Han SY Kim HS Kang YH 《Journal of agricultural and food chemistry》2012,60(10):2730-2739
Adipokines have been implicated in the pathogenesis of atherosclerosis via pro-inflammatory mechanisms contributing to insulin resistance. The adipokine resistin causes endothelium dysfunction, which plays an important role in sustaining atherogenesis. This study investigated whether resistin induced expression of cell adhesion molecules and integrins in endothelial cells and THP-1 monocytes and whether such induction was attenuated by 1-20 μM caffeic acid. Resistin enhanced endothelial expression of vascular cell adhesion molecule 1 (VCAM-1), intercellular cell adhesion molecule 1 (ICAM-1), and E-selectin and monocyte expression of β1, β2, and α4 integrins. The enhancement of these proteins was diminished by caffeic acid with reduced THP-1 cell adhesion on activated endothelium. Caffeic acid at ≤20 μM demoted resistin-stimulated interleukin 8 (IL-8) production responsible for ICAM-1 and β2 integrin induction. The endothelial up-regulation of IL-8 secretion by resistin entailed toll-like receptor 4 (TLR4) activation, but caffeic acid diminished IL-8 production and TLR4 induction. Furthermore, caffeic acid encumbered resistin-activated nuclear factor κB (NF-κB) signaling. These results demonstrate that caffeic acid blocked monocyte trafficking to resistin-activated endothelium via disturbing NF-κB signaling responsive to IL-8. Therefore, caffeic acid may have therapeutic potential in preventing obesity-associated atherosclerosis. 相似文献
986.
Doyoon Kim Chanki Kim Byungsik Chun Jae-Woo Park 《Water, air, and soil pollution》2012,223(6):3195-3206
We examined the sorption of heavy metals and polycyclic aromatic hydrocarbons (PAHs) to surface-oxidized activated carbon (AC) and its effect on the distribution of those compounds in sediments. Created surface oxygen groups on AC enhanced the sorption of copper, which is superior in sorption competition, in the marine sediments. In case of cadmium, aqueous chemistry altered by AC addition, such as pH, has greater impact on the bioavailability according to the result of a sequential extraction combined with the pore water concentration measurements. Oxidized AC exhibited 2.3 times more adsorption of reduced bioavailable copper while 23% of bioavailable cadmium was adsorbed onto unmodified AC. No significant changes in BET surface area, pore volume, and AC/water distribution coefficient (K AC) of PAHs were observed with surface-oxidized AC. The largest difference in K AC after the oxidation was only 0.14 log unit. Consequently, freely dissolved aqueous concentrations of PAHs were reduced by more than 96% for all tested ACs in a week despite the increased Cu sorption on AC. This indicates that enhanced metal sorption by surface oxidation of AC is less significant in controlling bioavailability of PAHs in sediments than particle size or sorbent dose. 相似文献
987.
Doubled haploid wheat lines developed from a cross between a hard white winter wheat variety of normal starch endosperm and a waxy wheat variety were used to determine the effects of allelic variation in Wx‐1, Glu‐D1, Glu‐B3, and Pinb‐D1 loci on physiochemical properties of flour, noodle dough properties, and textural quality of cooked noodles. Milling yield, damaged starch content, protein content, and SDS sedimentation volume of flour were influenced the most by allelic composition of Pinb‐D1 loci, less by Wx‐1 loci, and least by Glu‐B3. Wheat lines carrying Pinb‐D1b or Glu‐B3h alleles exhibited higher milling yield and damaged starch content of flour than those with Pinb‐D1a and Glu‐B3d alleles. Wheat lines carrying the Pinb‐D1b allele were higher in protein content and SDS sedimentation volume than those carrying Pinb‐D1a. Mixograph water absorption was largely influenced by allelic composition of Wx‐1 loci, whereas mixograph mixing time and mixing tolerance were predominantly determined by allelic composition of Glu‐D1 loci. Amylose content and pasting properties of starch were mainly determined by allelic composition of Wx‐1 loci with little influence by allelic compositions of Glu‐D1, Glu‐B3, and Pinb‐D1 loci. Allelic composition of Wx‐1 loci contributed 53.4% of the variation in optimum water absorption of noodle dough and 26.7% of the variation in thickness of the noodle dough sheet. The variation of 7.8% in optimum water absorption of noodle dough was contributed by the allelic composition of Pinb‐D1 loci. Allelic composition of Wx‐1 loci was responsible for 73.2, 74.4, and 59.6% in the variation of hardness, springiness, and cohesiveness of cooked noodles, respectively. Cohesiveness of cooked noodles was also influenced by the allelic compositions of Glu‐B3 and Pinb‐D1 loci to a smaller extent. 相似文献
988.
Taeil Jang Myungpyo Jung Eunjeong Lee Seongwoo Park Joonho Lee Hanseok Jeong 《Irrigation Science》2013,31(5):1225-1236
Irrigation water quality influences many aspects of agroecosystems, but less is known about how complex microbial and biological communities respond to changing water quality due to causes such as reuse irrigation. The objectives of this study are to monitor and assess the environmental impacts of reclaimed wastewater irrigation on water quality and soil that might cause potential health hazards and to assess its agro-environmental effects. Two sites, which are irrigated by filtered wastewater after UV (Ultraviolet) treatment and from an agricultural reservoir that satisfied the agricultural water quality standards of Korea, were selected as treatment and control, respectively. The environmental impacts of irrigation water quality on paddy soil, microorganisms, and arthropods were investigated. Monitoring results for water, soil, health risks, and eco-environments of the reclaimed wastewater irrigation site demonstrated no adverse effects in the paddy field. This research showed that reclaimed wastewater irrigation did not present significant environmental risks for the rice paddy agroecosystem, although long-term monitoring is needed to fully characterize its effects. 相似文献
989.
990.
Young-Jin Koh Jong-In Park Nasar Uddin Ahmed Hee-Jeong Jung Kwon-Kyoo Kang Yoonkang Hur Yong-Pyo Lim Ill-Sup Nou 《European journal of plant pathology / European Foundation for Plant Pathology》2013,136(2):317-322
Brassica rapa (chinese cabbage) is one of the main vegetable crops grown in Asian countries. Pectobacterium carotovorum subsp. carotovorum causes severe economic loss in this crop as well as in other Brassica crops through soft rot disease. Cysteine proteases like bromelain, papain or ficin show toxic effects to herbivorous insects and pathogenic bacteria. They have been known to be critical factors in plant defence mechanisms. The current study investigated the effect of bromelain gene (BL1) of pineapple (Ananas comosus L. Merrill) on enhancing resistance to soft rot in transgenic Brassica rapa ‘Seoulbaechu’. Three homozygous T2 lines were inoculated with Pectobacterium carotovorum subsp. carotovorum and BL8-2 line showed the lowest rate of infected leaves (RIL) in both wound inoculation and non-wound inoculation, when the non-infected line showed 100 % RIL in both cases. The highest expression of BL1 gene was also observed in BL8-2 homozygous line. Thus, the over-expressed BL1 gene conferred enhanced resistance to soft rot in Brassica rapa. 相似文献