全文获取类型
收费全文 | 232篇 |
免费 | 15篇 |
专业分类
林业 | 11篇 |
农学 | 4篇 |
基础科学 | 3篇 |
68篇 | |
综合类 | 26篇 |
农作物 | 23篇 |
水产渔业 | 14篇 |
畜牧兽医 | 55篇 |
园艺 | 15篇 |
植物保护 | 28篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 12篇 |
2020年 | 13篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 15篇 |
2016年 | 12篇 |
2015年 | 8篇 |
2014年 | 17篇 |
2013年 | 18篇 |
2012年 | 16篇 |
2011年 | 10篇 |
2010年 | 18篇 |
2009年 | 9篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有247条查询结果,搜索用时 62 毫秒
81.
Emmanouil Roditakis Christina Skarmoutsou Marianna Staurakaki María del Rosario Martínez‐Aguirre Lidia García‐Vidal Pablo Bielza Khalid Haddi Carmelo Rapisarda Jean‐Luc Rison Andrea Bassi Luis A Teixeira 《Pest management science》2013,69(2):217-227
BACKGROUND: Tuta absoluta(Meyrick) is one of the most serious pests of tomato recently introduced in the Mediterranean region. A novel bioassay method designed for the accurate determination of insecticide toxicity on T. absoluta (IRAC method No. 022) was validated by three different laboratories [Greece (NAGREF), Italy (UC) and Spain (UPCT)] on European populations. RESULTS: The insecticides indoxacarb and chlorantraniliprole were used as reference products. The IRAC leaf dip method is easy to perform, producing repeatable, homogeneous responses. LC50 values for indoxacarb ranged between 1.8 and 17.9 mg L?1 (NAGREF), 0.93 and 10.8 mg L?1 (UC) and 0.20 and 0.70 mg L?1 (UPCT), resulting in a tenfold, 12‐fold and fourfold difference between the least and most susceptible populations at each laboratory respectively. For chlorantraniliprole, LC50 values ranged between 0.10 and 0.56 mg L?1 (NAGREF), 0.23 and 1.34 mg L?1 (UC) and 0.04 and 0.24 mg L?1 (UPCT), resulting in a sixfold difference in all three cases. Overall, UPCT reported lower mean LC50 to indoxacarb, while UC reported higher LC50 to chlorantraniliprole. CONCLUSIONS: The new bioassay is reliable, providing a useful tool in the design of IRM strategies. Within each country/lab, the variability observed in the results for both indoxacarb and chlorantraniliprole can be attributed to natural variation. Future research is necessary to determine the extent to which it is possible to compare results among laboratories. Copyright © 2012 Society of Chemical Industry 相似文献
82.
The resistance of tumor cells to a broad range of anticancer agents continues to be a problem for the success of cancer chemotherapy. Multidrug resistance (MDR) is due in part to three drug transporter proteins: ABCB1/P-glycoprotein (P-gp), ABCC1/multidrug resistance protein 1 (MRP1) and ABCG2/breast cancer resistance protein (BCRP). These transporters are part of the ATP-binding cassette (ABC) superfamily, whose members function as ATP-dependent drug-efflux pumps. Their activity can be blocked by various drugs such as verapamil (calcium channel blocker) and cyclosporin A (immunosuppressive agent), etc. These compounds are called MDR modulators or reversals. This review highlights several marine natural products with reversal effect on multidrug resistance in cancer, including agosterol A, ecteinascidin 743, sipholane triterpenoids, bryostatin 1, and welwitindolinones. 相似文献
83.
Ten genotypes of rice (Oryza sativa L.) were grown for 30 d in complete nutrient solution with 1 mmol/L (N-insufficient),4 mmol/L (N-moderate) and 10 mmol/L (N-high) nitrogen levels,and nitrogen efficiency (NE) was analyzed.Growth performance,measured in terms of fresh weight,dry weight and lengths of root and shoot,was higher in N-efficient than in N-inefficient rice genotypes at low N level.Of these 10 genotypes,Suraksha was identified as the most N-efficient,while Vivek Dhan the most N-inefficient.To find out the physiological basis of this difference,the nitrate uptake rate of root and the activities of nitrate assimilatory enzymes in leaves of N-efficient and N-inefficient rice genotypes were studied.Uptake experiments revealed the presence of two separate nitrate transporter systems mediating high-and low-affinity nitrate uptake.Interestingly,the nitrate uptake by the roots of Suraksha is mediated by both high-and low-affinity nitrate transporter systems,while that of Vivek Dhan by only low-affinity nitrate transporter system.Study of the activities and expression levels of nitrate assimilatory enzymes in N-efficient and N-inefficient rice genotypes showed that nitrate reductase (NR) and glutamine synthetase (GS) play important roles in N assimilation under low-nitrogen conditions. 相似文献
84.
Shahid Mahboob Abdul Rauf Muhammed Ashraf Tayyaba Sultana Salma Sultana Farhat Jabeen Muhammad Ibrahim Rajoka H. F. Alkahem Al-Balawi Khalid A. Al-Ghanim 《Aquaculture International》2012,20(3):455-466
Current study investigated the fermentative production of cell mass and crude protein using an axenic culture of the thermotolerant strain of Chlorella vulgaris grown mixotrophically in an illuminated 10-l glass bioreactor. The process was then upscaled to 1,000-l bioreactor. The organism supported maximum specific growth rate, crude protein volumetric productivity, and specific productivity of 1.2?day?1, 2.26?g?l?1?day?1, and 0.76?g?g?1?day?1, respectively, with urea as nitrogen source. Gibbs free energy, enthalpy, and entropy values for its formation were 74.3, 56. 2?kJ?mol?1, and ?59.1?J?mol?1?K?1, respectively, in both reactors and corresponded to those of thermotolerant organisms. Algal biomass grown in 10-l bioreactor contained 0.52?±?0.03, 12.6?±?2.0, 60.0?±?4.5, 0.4?±?0.02, 4.5?±?0.2, 12?±?0.5, and 3.81?±?0.5% carotenoids, carbohydrates, crude protein, DNA, RNA, lipids, and total chlorophyll, respectively. Dry biomass supported good growth of fish larvae comparable with that on commercial diet. 相似文献
85.
86.
Khalid Elhindi Ahmed Sharaf El Din Eslam Abdel-Salam Abdallah Elgorban 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(7):583-592
Although the salt resistance mechanisms in plants have received much consideration for many years, varieties’ differences affecting salt resistance are still unsettled. Within the Ocimum genus there occur about 200 species in different varieties and forms. A pot experiment was performed to better understand salt stress responses in crop plants; we compared the impacts of salinity stress on growth and physio-biochemical characteristics in three varieties of basil (Ocimum basilicum) var. odoratus, O. b. var. alba and O. b. var. purpurascens) grown under four levels of salinity stress (0, 50, 100, and 150?mM NaCl) with mycorrhiza (Glomus clarum Nicol. &; Schenck) or without. Results showed significant differences within salinity treatments in all cultivars studied. In this study, the biomass production and physio-biochemical parameters of all cultivars reduced with raised salinity levels except concentration of reducing sugars, sodium, and proline at 150 mM of NaCl, only the variety ‘purpurascens’ didn't show reduction and observed resistant against severe salinity. The colonization of arbuscular mycorrhiza fungi enhanced the biomass production and accumulation of nutrients, reducing sugars, total soluble carbohydrates, photosynthetic pigments, proline, and protein by reducing Na. This study should help understand the function of AMF fungi in basil cultivars’ tolerance to salinity stress. 相似文献
87.
Liwei Liu Ying Zhou Junjie Wu Wei Zhang Khalid Abbas Liang Xu‐Fang Yuliang Luo 《Aquaculture Research》2014,45(12):1932-1941
A feeding trial was conducted for 8 weeks to evaluate the effects of graded levels of neutral phytase supplementation using pretreatment or spraying method on growth performance, body composition, bone mineral content and serum biochemical parameter in grass carp, Ctenopharyngodon idellus. A control diet without phytase was added and six additional diets were arranged as a 2 × 3 factorial with two methods (pretreatment or spraying) and three levels of phytase (500, 1000 or 1500 U kg?1). The results showed that supplemental phytase at different levels in the diet and with different application methods all improved weight gain, specific growth rate and protein efficiency ratio of grass carp (P < 0.05). The feed conversion ratio in phytase‐supplemented groups was lower than the control. Dietary phytase addition reduced the lipid content in the whole body of grass carp. Phytase supplementation with different method increased ash and mineral (P, Ca, Mg and Zn) contents in whole‐body and vertebra (P < 0.05). The increase in these mineral contents was also observed in the serum. Based on the results, we may conclude that: 1) supplemental dietary phytase, regardless of the application methodology, improved the growth performance and nutrient utilization in grass carp; 2) the pretreatment mode of phytase application was more effective than spraying at the same phytase level. 相似文献
88.
Muhammad Asif Naeem Muhammad Khalid Muhammad Aon Ghulam Abbas Muhammad Amjad Behzad Murtaza 《Journal of plant nutrition》2018,41(1):112-122
A pot study was conducted to assess the combined effect of biochar (B) with compost (Com) and inorganic fertilizers (F) for improving nutrient acquisition and productivity of maize. Seven different treatments, including B (1% w/w), F (Recommended nitrogen, phosphorus and potassium (NPK): 60, 30 and 25 mg kg─1), Com (1.5% w/w), Com+F (1.5% + NPK), B+F (1% + NPK), B+Com (0.5% + 0.75%), B+Com+F (0.5% + 0.75% + NPK) along with a control (C) without B, Com and F were applied in pots with four replications. The results showed that growth and grain yield of maize increased by the application of B, Com and F compared with C, but B+Com+F was more effective than their sole application (i.e. B, Com and F). Highest leaf chlorophyll content, gas exchange attributes and nutrient concentrations: N, P and K in shoot and grains were observed, where B+Com+F was applied followed by Com+F > B+F > B+Com > F > Com > B > C. Soil properties such as soil organic carbon (SOC), N, P, and K were significantly increased, whereas soil pH was decreased by the combination of B with Com and F. Hence, application of B in combination with Com and F (B+Com+F) could be a good management strategy to enhance crop productivity and improve soil properties. 相似文献
89.
90.
Tito Bacca Khalid Haddi Maria Pineda Raul Narciso C Guedes Eugênio E Oliveira 《Pest management science》2017,73(2):i-i
The cover image, by Eugênio E. Oliveira et al., is based on the Research Article Pyrethroid resistance is associated with a kdr‐type mutation (L1014F) in the potato tuber moth Tecia solanivora, DOI: 10.1002/ps.4414 . Photo Credit: Edison Torrado‐Leon.