首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   233篇
  免费   67篇
  国内免费   14篇
  2024年   3篇
  2023年   6篇
  2022年   7篇
  2021年   10篇
  2020年   9篇
  2019年   20篇
  2018年   4篇
  2017年   21篇
  2016年   14篇
  2015年   14篇
  2014年   31篇
  2013年   28篇
  2012年   17篇
  2011年   13篇
  2010年   9篇
  2009年   13篇
  2008年   10篇
  2007年   15篇
  2006年   12篇
  2005年   7篇
  2004年   6篇
  2003年   3篇
  2002年   7篇
  2001年   3篇
  2000年   3篇
  1999年   3篇
  1998年   1篇
  1996年   2篇
  1995年   3篇
  1994年   2篇
  1992年   5篇
  1991年   3篇
  1990年   2篇
  1985年   2篇
  1984年   1篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1977年   1篇
排序方式: 共有314条查询结果,搜索用时 93 毫秒
181.
Olive mill wastewater (OMW) was digested in its original composition (100% v/v) in an anaerobic hybrid. High concentrations (54–55 kg COD m−3), acid pH (5.0) and lack of alkalinity and nitrogen are some OMW adverse characteristics. Loads of 8 kg COD m−3 d−1 provided 3.7–3.8 m3 biogas m−3 d−1 (63–64% CH4) and 81–82% COD removal. An effluent with basic pH (8.1) and high alkalinity was obtained. A good performance was also observed with weekly load shocks (2.7–4.1, 8.4–10.4 kg COD m−3 d−1) by introducing piggery effluent and OMW alternately. Biogas of 3.0–3.4 m3 m−3 d−1 (63–69% CH4) was reached.Developed biomass (350 days) was neither affected by raw OMW nor by organic shocks. Through the effluents complementarity concept, a stable process able of degrading the original OMW alone was obtained. Unlike what is referred, OMW is an energy resource through anaerobiosis without additional expenses to correct it or decrease its concentration/toxicity.  相似文献   
182.
陆并伟  郭玉杰  张玲  徐桂芬  刘丹 《生物磁学》2011,(18):3524-3526,3552
目的:通过对医务人员在急诊手术中职业暴露的情况调查,了解急诊手术中标准预防现状,提出合理化建议和措施。方法:对2007年6月.2010年5月手术患者乙肝、丙肝、梅毒、艾滋病的阳性率进行比较,现场调查急诊手术中防护用品的使用情况。结果:手术患者乙肝、丙肝、梅毒、艾滋病的阳性率逐年上升,职业暴露的危险性越来越大;急诊手术中医务人员防护用品使用率的高低取决于血液、体液、分泌物的污染程度。结论:对医务人员要加强职业安全教育,强化标准预防,提高医务人员的整体防护水平,避免或减少职业暴露的危害,在救死扶伤的同时,保护好自身安全。  相似文献   
183.
目的:总结吸毒致股动脉假性动脉瘤复合手术的配合方法.方法:针对吸毒患者的特征,以及股动脉假性动脉瘤对患者造成的不良影响,制定复合手术的配合方法,完善股动脉假性动脉瘤复合手术配合操作规范、流程和路径.结果:通过实践,形成了一套完善的、规范的、标准化的配合方案,5例患者术中均得到精细化、全方位的护理,确保了患者术中的安全,顺利完成手术,术后均痊愈出院.结论:股动脉假性动脉瘤复合手术配合方案的形成对提高手术的安全性,减少并发症,保证手术的顺利进行具有重要的临床意义.  相似文献   
184.
Extracellular lipase of the yeast Candida rugosa was produced via high cell density fed-batch fermentations using palm oil as the sole source of carbon and energy. Feeding strategies consisted of a pH-stat operation, foaming-dependent control and specific growth rate control in different experiments. Compared to foaming-dependent feeding and the pH-stat operation, the specific growth rate control of feeding proved to be the most successful. At the specific growth rate control set at 0.05 h−1, the final lipase activity in the culture broth was the highest at ∼700 U L−1. This was 2.6-fold higher than the final enzyme activity obtained at a specific growth rate control set at 0.15 h−1. The peak enzyme concentration achieved using the best foaming-dependent control of feeding was around 28% of the peak activity attained using the specific growth rate control of feeding at 0.05 h−1. Similarly, the peak enzyme concentration attained using the pH-stat feeding operation was a mere 9% of the peak activity attained by specific growth rate control of feeding at a set-point of 0.05 h−1. Fed-batch fermentations were performed in a 2 L stirred-tank bioreactor (30 °C, pH 7) with the dissolved oxygen level controlled at 30% of air saturation.  相似文献   
185.
186.
It can be challenging to understand the evolution of sociality, particularly the occurrence of co‐operation by non‐kin. Southern flying squirrels (Glaucomys volans) are an interesting example of non‐kin co‐operation because of the mutual benefits obtained by social thermoregulation during winter. Because group survival confers benefits to the entire group, flying squirrels may also follow an aggregation economy, whereby co‐operative foraging during winter is advantageous. However, the extent of such social foraging in flying squirrels is unknown. We tested for social foraging of southern flying squirrels, and also for relatedness among foraging groups. To determine the structure of foraging groups, we set up and remotely monitored feeding stations and nest cavities. All squirrels at the study site were tagged with passive integrated transponder (PIT) tags and nests and feeding stations were monitored with automated PIT‐tag recorders for a 24‐month period. Squirrels were found most often foraging alone. Squirrels that were recorded foraging together comprised unrelated individuals that were also found to share nest cavities. Squirrels were also recorded travelling farther distances between nest cavity and feeding station in the winter season than in the summer season, suggesting that, during winter, squirrels trade‐off proximity to food caches for membership in a nest group. Our data suggest that squirrels forage and cache alone in their summer home range and make solitary returns to this summer range to collect their cache during the winter months, despite exhibiting social winter nesting. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 113 , 1126–1135.  相似文献   
187.
目的:探讨地佐辛超前镇痛对全麻条件下鼻内镜手术后预防气管拔管时不良反应的可行性及安全性。方法:美国麻醉师协会(ASA)评分Ⅰ~Ⅱ级,行择期鼻内镜手术患者60例,随机分为试验组和对照组(n=30)。常规心电监测后用咪达唑仑0.04mg/kg,芬太尼5/μg/kg,丙泊酚2mg/kg,阿曲库铵0.6mg/kg行麻醉诱导,丙泊酚加七氟醚静吸复合维持麻醉。试验组手术开始前15min肌肉注射地佐辛0.1mg/kg,对照组则给予同等容量的生理盐水。记录术前、术中、拔管时及拔管后的收缩压、舒张压、心率及血氧饱和度、苏醒时间、拔管时躁动、寒战情况以及术后24h疼痛情况。结果:术后气管拔管时试验组收缩压、舒张压及心率显著低于对照组(P〈0.05),且试验组术后24h疼痛视觉模拟评分(VAS)明显低于对照组(P〈0.05)。结论:地佐辛超前镇痛用于鼻内镜手术,能有效保持气管拔管时血流动力学的平稳,减少不良反应的发生,减轻患者疼痛。  相似文献   
188.
目的:观察保留乳房手术治疗早期乳腺癌的临床治疗效果及其安全性。方法:回顾性分析我院2008 年5 月—2010 年5 月间 收治的92 例行保乳手术的早期乳腺癌患者的临床资料,观察实施保乳手术并综合后的治疗疗效和患者生活质量变化。结果:全 部患者均顺利接受手术,近期乳房外形保持较好,美容效果好,手术并发症少。术后随访20~44 个月,1 例局部复发,1 例肝转移, 无死亡病例。结论:保乳手术治疗早期乳腺癌的美容效果好,并发症少,疗效显著;术前严格掌握手术适应症,术后规范的综合治 疗,是取得良好效果的基础。  相似文献   
189.
目的:探讨梗阻性低位直肠癌保肛治疗(直肠癌前切除术(dixon手术))的可行性及术后肠瘘的防治。方法:回顾性分析我科2009年1月-2012年1月梗阻性低位直肠癌的保肛治疗(dixon)24例手术患者(梗阻性保肛组)临床资料及非梗阻性低位直肠癌保肛治疗(dixon)的24例患者(非梗阻性保肛组)临床资料,比较梗阻性与非梗阻性低位肠梗阻保肛治疗的临床疗效,分析梗阻性低位肠梗阻保肛治疗的可行性。结果:梗阻性保肛组住院天数:11.9天,非梗阻性肠梗阻保肛组8.7天P0.05;梗阻性保肛组发生肠瘘:4例(16.7%),非梗阻性肠梗阻保肛组发生肠瘘:1例(4.2%)P0.05,经充分引流后肠瘘愈合,无1人死亡,两组术后至出院期间死亡人数:0例;梗阻性保肛组肠功能恢复(以排气排便为指标):5.1天,非梗阻性保肛组肠功能恢复:3.8天,P0.05;术后6个月腹泻便秘患者两组相同为24人;术后6个月梗阻性保肛组肿瘤复发6人(25%),非梗阻性保肛组肿瘤复发5人(20.8%),P0.05。结论:梗阻性低位肠梗阻保肛治疗住院期疗效较非梗阻性保肛组差,中远期疗效无明显差异。梗阻性低位直肠癌可行保肛治疗。  相似文献   
190.
The scope of this study is to evaluate the performance of internal loop airlift bioreactor (ILALR) in treating synthetic wastewater containing phenol and m-cresol, in single and multi component systems. The microbe utilized in the process was an indigenous mixed strain of Pseudomonas sp. isolated from a wastewater treatment plant. The reactor was operated at both lower and higher hydraulic retention times (HRTs) i.e., 4.1 and 8.3 h, respectively, by providing an inlet feed flow rate of 5 and 10 mL/min. Shock loading experiments were also performed up to a maximum concentration of 800 mg/L for phenol at 8.3 h HRT and 500 mg/L for m-cresol at 4.1 h HRT. The study showed complete degradation of both phenol and m-cresol, when they were degraded individually at a HRT of 8.3 h. Experiments with both phenol and m-cresol present as mixtures were performed based on the 22 full factorial design of experiments.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号