全文获取类型
收费全文 | 2592篇 |
免费 | 865篇 |
国内免费 | 38篇 |
专业分类
林业 | 372篇 |
农学 | 432篇 |
基础科学 | 178篇 |
504篇 | |
综合类 | 898篇 |
农作物 | 226篇 |
水产渔业 | 117篇 |
畜牧兽医 | 441篇 |
园艺 | 81篇 |
植物保护 | 246篇 |
出版年
2025年 | 19篇 |
2024年 | 80篇 |
2023年 | 62篇 |
2022年 | 112篇 |
2021年 | 142篇 |
2020年 | 134篇 |
2019年 | 111篇 |
2018年 | 76篇 |
2017年 | 109篇 |
2016年 | 102篇 |
2015年 | 139篇 |
2014年 | 131篇 |
2013年 | 156篇 |
2012年 | 159篇 |
2011年 | 166篇 |
2010年 | 179篇 |
2009年 | 170篇 |
2008年 | 151篇 |
2007年 | 145篇 |
2006年 | 141篇 |
2005年 | 101篇 |
2004年 | 86篇 |
2003年 | 65篇 |
2002年 | 83篇 |
2001年 | 93篇 |
2000年 | 70篇 |
1999年 | 71篇 |
1998年 | 56篇 |
1997年 | 58篇 |
1996年 | 50篇 |
1995年 | 34篇 |
1994年 | 34篇 |
1993年 | 45篇 |
1992年 | 37篇 |
1991年 | 31篇 |
1990年 | 30篇 |
1989年 | 16篇 |
1988年 | 18篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有3495条查询结果,搜索用时 15 毫秒
21.
介绍了马来酰肼在大蒜中残留量的分光光度分析方法。国内未见报道。本法亦可作为其它作物或动物组织中马来酰肼残留的分析。 相似文献
22.
23.
Summary Aseptically cultured shoots of Chinese gooseberry exhibited growth disorder and morphological aberrances, and some died after being exposed to sufficient gamma-ray irradiation. The death rate was dose dependant and the LD50 was 80–90 Gy and 50–60 Gy respectively for cv. Hayward and clone 4. All petiole explants irradiated with gamma-ray could form calli as the control, but the rate of differentiation of adventitious shoots of the petiole explants decreased and was dependant on dose. Sensitivity of the shoot or petiole explants to gamma-ray irradiation varied with species. Gamma-ray irradiation did not deter either the 2-node segments from producing axillary shoots M1, M2, and M3 or the advantitious shoots originating in the petiole explants and the M3 shoots from forming advantitious roots. Therefore, using aseptically cultured axillary or adventitious buds for mutation breeding of Chinese gooseberry is feasible. A bacterium surviving in the explants lessened the efficiency of these two in vitro techniques in mutation breeding of Chinese gooseberry.Abbreviations IAA
3-indole acetic acid
- IBA
-indole butyric acid
- MS
Murashige & Skoog (1962) 相似文献
24.
[Objectives]To probe into the treatment effects of soya lecithin powder combined with conventional therapy on chronic hepatitis B.[Methods]A total of 120 patien... 相似文献
25.
Mohamed Abdel‐Shafi Abdel‐Samie Jingjing Wan Weining Huang Okkyung Kim Chung Baocai Xu 《Cereal Chemistry》2010,87(5):454-460
The effects of cumin and ginger as antioxidants on dough mixing properties and cookie quality were evaluated. Antioxidant activities in cookies were estimated by total phenolic compounds (TPC) contents and free radical scavenging activities. The cookie dough development was evaluated using Mixolab equipment which showed that addition of cumin did not change dough stability and C2, but decreased C3 and C4. While the addition of 5% ginger decreased dough stability (from 8.4 in the control sample to 6.7 min with 5% ginger addition), C2 (from 0.49 in the control sample to 0.31 N·m with 5% ginger addition), C3, and C4. Cookies formulated with addition of cumin and ginger had increased spread ratios, were softer, and had lower L* and b* values (were darker) than the control. Sensory analysis showed that cookies with cumin and ginger additions had overall acceptability similar to that of the the control with a slightly darker appearance, as confirmed by color determination. Using cumin and ginger significantly increased TPC contents from 78.5 in the control to 93.0 and 109.8 mg of gallic acid equivalent/100 g, respectively. Similar results were observed in the antioxidant activity measured by 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), which increased from 41.0% in the control to 51.5% and 64.6%, respectively, for cookies with 5% addition of cumin and ginger. 相似文献
26.
Hou MF Tang XY Zhang WD Liao L Wan HF 《Journal of agricultural and food chemistry》2011,59(21):11456-11460
In this study, polyphenol oxidase (PPO) was extracted from commercial potatoes. Degradation of pentachlorophenol by potato PPO was investigated. The experimental results show that potato PPO is more active in weak acid than in basic condition and that the optimum pH for the reaction is 5.0. The degradation of pentachlorophenol by potato PPO reaches a maximum at 298 K. After reaction for 1 h, the removal of both pentachlorophenol and total organic carbon is >70% with 6.0 units/mL potato PPO at pH 5.0 and 298 K. Pentachlorophenol can be degraded through dechlorination and ring-opening by potato PPO. The work demonstrates that pentachlorophenol can be effectively eliminated by crude potato PPO. 相似文献
27.
Martin Wiesmeier Olivia Kreyling Markus Steffens Philipp Schoenbach Hongwei Wan Martin Gierus Friedhelm Taube Angelika Kölbl Ingrid Kögel‐Knabner 《植物养料与土壤学杂志》2012,175(3):434-442
The assessment of grassland degradation due to overgrazing is a global challenge in semiarid environments. In particular, investigations of beginning steppe degradation after a change or intensification of the land use are needed in order to detect and adjust detrimental land‐use management rapidly and thus prevent severe damages in these sensitive ecosystems. A controlled‐grazing experiment was established in Inner Mongolia (China) in 2005 that included ungrazed (UG) and heavily grazed plots with grazing intensities of 4.5 (HG4.5) and 7.5 (HG7.5) sheep per hectare. Several soil and vegetation parameters were investigated at all sites before the start of the experiment. Topsoil samples were analyzed for soil organic C (SOC), total N (Ntot), total S (Stot), and bulk density (BD). As vegetation parameters, aboveground net primary productivity (ANPP), tiller density (TD), and leaf‐area index (LAI) were determined. After 3 y of the grazing experiment, BD increased and SOC, Ntot, Stot, ANPP, and LAI significantly decreased with increasing grazing intensity. These sensitive parameters can be regarded as early‐warning indicators for degradation of semiarid grasslands. Vegetation parameters were, however, more sensitive not only to grazing but also to temporal variation of precipitation between 2006 and 2008. Contrary, soil parameters were primarily affected by grazing and resistant against climatic variations. The assessment of starting conditions in the study area and the application of defined grazing intensities is essential for the investigation of short‐term degradation in semiarid environments. 相似文献
28.
Multi-floret and single-floret injection inoculation methods were used to test 1076 accessions of Triticum for resistance to initial infection and resistance to pathogen spread within spike tissue respectively. The data obtained between years or inoculation dates were comparatively similar and were little influenced by climatic factors, especially humid condition. All the tested materials uniformly exhibited susceptibility to initial infection, but there were great differences in resistance to spread among species or cultivars. The diploid and tetraploid wheats were severely susceptible. Only 30 genotypes of common wheat of T. aestivum concv. vulgare showed high resistance to spread. The highest frequency of high spread resistance existed in these landraces which were distributed in Zhejiang, Hubei, Hunan, Jiangsu provinces and Shanghai City, Guizhou, Sichuan and Yunnan provinces ranked second. The majority of wheat landraces from Hebei, Shanxi, Shaanxi Province and Beijing City showed susceptibility or high susceptibility. No resistance was found in Tibetian wheats. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
29.
30.
Yongsun Kim Seung Hoon Lee Wan Hee Kim Oh-Kyeong Kweon 《Journal of veterinary science (Suw?n-si, Korea)》2016,17(1):123-126
Thirty-four dogs with no deep pain perception due to acute thoracolumbar intervertebral disc disease underwent decompression surgery within 1 week of diagnosis. All dogs underwent hemilaminectomy. Adipose derived mesenchymal stem cells (AD-MSCs) were transplanted into the injured spinal cord parenchyma for the AD-MSCs transplant dogs. Long-term outcome was evaluated at the end of the follow-up period (> 6 months). AD-MSCs combination treatment showed better recovery outcomes compared to decompression surgery alone. These results indicate that this stem cell therapy is a potential therapeutic strategy to overcome the limitations of treatment for spinal cord injury in clinical medicine. 相似文献