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151.
To evaluate the atmospheric load of reactive gaseous nitrogen in the fast-developing Eastern China region, we compiled inventories of nitrous oxide (N2O), nitrogen oxide (NOx) and ammonia (NH3) emissions from a typical rural catchment in Jiangsu province, China, situated at the lower reach of the Yangtze River. We considered emissions from synthetic N fertilizer, human and livestock excreta, decomposition of crop residue returned to cropland and residue burning, soil background and household energy consumption. The results showed that, for the 45.5 km2 catchment, the annual reactive gaseous emission was 279 ton N, of which 7% was N2O, 16% was NOx and 77% was NH3. Synthetic N fertilizer application was the dominant source of N2O and NH3 emissions and crop residue burning was the dominant source of NOx emission. Sixty-seven percent of the total reactive gaseous N was emitted from croplands, but on a per unit area basis, NOx and NH3 emissions in residential areas were higher than in croplands, probably as a result of household crop residue burning and extensive human and livestock excreta management systems. Emission per capita was estimated to be 18.2 kg N year−1 in the rural catchment, and emission per unit area was 56.9 kg N ha−1year−1 for NH3 + NOx, which supports the observed high atmospheric N deposition in the catchment. Apparently, efficient use of N fertilizer and biological utilization of crop straw are important measures to reduce reactive gases emissions in this rural catchment.  相似文献   
152.
BACKGROUND: The authors investigated whether fluorescent pigment in thermoset melamine microcapsules incorporated into monitoring baits would be excreted in the faeces of wild house mice in a quantity and intensity that would be detectable by a human observer. RESULTS: Experimental mice produced 24–116 UV‐visible faecal pellets per 24 h; the mean dry weight was 582 mg. The number and weight of the faeces was independent of mouse sex and weight. The defecation of UV‐visible faeces began at 2–3 h, peaked at 5–8 h and was complete at 17 h after bait ingestion. The detectability of the highly fluorescent faecal pellets using a small UV flashlight approached 100%, and no false positives were recorded. CONCLUSION: The tested formulation is of significant value for rodent pest monitoring because faeces that are highly visible by UV light are produced for 15 h by mice after ingestion, and their detection is easy and unambiguous. Copyright © 2011 Society of Chemical Industry  相似文献   
153.
Objectives To investigate whether there are any changes in the tidal breathing flow volume loop (TBFVL) in calm, non-dyspnoeic dogs with intratracheal masses. Methods We compared 4 dogs with intratracheal masses (group 1) with 10 healthy dogs (group 2). Routine clinical and laboratory examinations of the dogs were unremarkable, except for episodic upper respiratory obstructive signs in the dogs in group 1. Lateral radiography of the neck and thorax showed that group 1 dogs had masses that appeared to protrude into the tracheal lumen. Tracheoscopy and surgery or necropsy was performed to confirm the presence of the mass. Arterial blood gas and TBFVL analysis was carried out in all dogs to assess respiratory status. Results The shape of the TBFVL for dogs in group 1 was narrower and ovoid compared with that for the group 2 dogs. Tidal volume and expiratory and inspiratory times were significantly reduced, whereas the respiratory rate was increased for dogs in group 1 compared with dogs in group 2. Arterial blood gas analysis was unremarkable for all dogs. Conclusions TBFVL is a non-invasive technique that is easy to perform and well tolerated by dogs. In the absence of abnormalities detected by routine diagnostic evaluations and arterial blood gas analysis in dogs with intratracheal masses, the TBFVL contributes to the definition of the physiologic status of the airways at the time of testing, and results suggests that these dogs breathe quite normally when they are calm and non-dyspnoeic.  相似文献   
154.
测试条件对啶虫脒毒土柱防白蚁效果的影响   总被引:2,自引:1,他引:2       下载免费PDF全文
将预防性杀白蚁药剂施在土壤中形成毒土层是当前控制白蚁为害的主要方法之一。以黄胸散白蚁Reticulitermes flaviceps为对象,啶虫脒为供试药剂,在室内进行毒土柱防白蚁效果测定。结果表明,供试白蚁数量和食物供应与否均对药效试验评价结果有较大影响,毒土柱长度对测试结果的影响与土壤中药剂浓度有关。当毒土柱长度达到10 cm时,所测结果即可反应药剂对白蚁的阻杀效果。用毒土柱法测定预防药剂防白蚁的效果时,建议用10 cm长的毒土柱,每个重复的白蚁数为工蚁100头,并用湿润滤纸片作为供试白蚁的食物和水源。  相似文献   
155.
细辛对黄胸散白蚁的毒效   总被引:16,自引:0,他引:16       下载免费PDF全文
为了开发新型白蚁预防药物,以黄胸散白蚁Reticulitermes flaviceps为试验对象,采用饲喂、驱避、毒土柱等方法,在室内测定了细辛Asarum sieboldii Miq.粉对白蚁的毒杀效果。结果表明,细辛粉对黄胸散白蚁有较好的毒杀效果和较强的驱避活性;毒土柱试验结果表明,细辛粉对黄胸散白蚁有较好的阻杀作用。在白蚁防治方面细辛具有一定的开发利用价值。  相似文献   
156.
新烟碱类杀虫剂抗药性研究进展   总被引:20,自引:0,他引:20       下载免费PDF全文
新烟碱类杀虫剂是一类新开发的杀虫剂。研究表明,害虫野外种群对其敏感性差弄较大,现已有多种害虫对吡虫啉和啶虫脒产生了抗性。初步研究显示,马铃薯叶甲对吡虫啉抗性以不完全隐性的常染色体遗传;抗性似不稳定,交互抗性谱随虫种而变化,抗性形成可能与多功能氧化酶和酯酶有关。合理轮用和高剂量杀死策略是治理其抗性的有效措施。  相似文献   
157.
蜜环菌菌索多糖对小鼠血糖及急性毒性作用研究   总被引:12,自引:3,他引:12  
本文研究了蜜环菌菌索多糖AMP - 1和AMP - 2组分对小鼠血糖及其急性毒性作用。结果表明 :AMP - 1能使正常小鼠的糖耐量增强 ;AMP - 1、AMP - 2均能抑制四氧啶糖尿病小鼠血糖升高 ;AMP - 2能显著降低四氧啶糖尿病小鼠的血糖 ;AMP - 1、AMP - 2 (灌胃剂量为 10g/kg/d)对供试小鼠无毒性作用 ,内脏器官均正常无损  相似文献   
158.
BACKGROUND: Respiratory distress syndrome (RDS) has been reported previously in premature calves. However, there have been no published data on the effect of surfactant replacement therapy in the treatment of premature calves with RDS. HYPOTHESIS: Surfactant replacement therapy added to the standard treatment for premature calves clinically diagnosed with RDS would increase the viability of the calves. ANIMALS: Twenty-seven premature calves with clinically diagnosed RDS. METHODS: Twenty calves were instilled intratracheally with bovine lung surfactant extract and provided with standard treatment for RDS (surfactant group). Seven calves were given only standard care for RDS without surfactant therapy and placed in the control group. Standard treatment for newborn calves with RDS includes warming, administration of intranasal oxygen, fluid replacement, administration of antibiotics, and immunoglobulin solution. Arterial blood samples were collected from the calves at 3 observation points, the first just before treatment (hour 0) and at 2 hours (hour 2) and 24 hours (hour 24) after treatment was started to determine if ventilation was adequate, improving, or deteriorating. Blood gases, pH, bicarbonate, and lactate concentrations were measured. RESULTS: In the surfactant group, mean partial pressure of oxygen significantly increased at hours 2 and 24. Mean partial pressure of carbon dioxide decreased and mean arterial blood pH increased at hour 24 in the surfactant group compared with the control group (P < .05). Of the 20 calves in the surfactant group, 12 survived and 8 died. All 7 calves in the control group died. CONCLUSIONS AND CLINICAL IMPORTANCE: The results of this study suggest that surfactant replacement therapy may reduce neonatal deaths in premature calves with clinically diagnosed RDS.  相似文献   
159.
农田管理措施对土壤有机碳周转及微生物的影响   总被引:2,自引:0,他引:2  
农田管理措施对农田生态系统碳循环影响显著,进而制约土壤肥力、农业生产及粮食安全,影响气候变化和环境健康。本文综述了不同农田管理措施(施肥方式、种植制度、耕作模式)对农田土壤有机碳、含碳温室气体排放和土壤微生物的影响。发现有机肥与无机肥配施情景下土壤有机碳增速最快,且施肥量与土壤碳库存在阈值效应;有机肥的施用增加了土壤中CO2排放通量,磷、钾两种肥料的施用与施用氮肥相比更能降低农田土壤排放温室气体产生的全球增温潜势;提高有机肥和磷肥的施用比例有利于土壤中微生物丰富度的提高和微生物量碳的积累。种植结构和种植密度均会影响农田土壤的碳储量,种植结构对农田生态系统温室气体排放影响显著,轮作和间作的种植模式与传统单一作物种植相比可有效减少农田含碳温室气体的排放,同时,轮作与连作相比更有利于土壤微生物多样性的增加。保护性耕作措施有利于农田土壤固碳效率的提高,可降低农田温室气体的排放,且对微生物活性、多样性、群落结构以及碳源利用情况均有积极影响。最后总结了国际主流碳模型在农田生态系统的应用概况,并提出了未来发展展望。  相似文献   
160.
生物质炭的固碳减排与合理施用   总被引:4,自引:1,他引:3  
近年来开展了大量短期一次性施用生物质炭对作物产量、土壤碳库和温室气体排放的研究。研究表明生物质炭能增加土壤碳库,但对作物产量、CH4和N2O排放的影响受生物质炭性质和土壤类型影响。生物质炭用在酸性土壤上比中性或碱性土壤上更能提高作物产量。草本或木本炭能减少N2O排放,但畜禽粪便炭不能减少N2O排放。在热带、亚热带地区生物质炭施用对N2O的减排作用小于温带地区。生物质炭的固碳减排效应除了受生物质炭类型、稳定性和施用区域影响外,还受制炭能耗和裂解气回收技术影响。在未来发展方向上,提出了亟需加强制炭技术、长期连续施用生物质炭效应和生物质炭性质与土壤类型互作研究。  相似文献   
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