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排序方式: 共有350条查询结果,搜索用时 15 毫秒
191.
192.
目的通过高脂饮食建立NAFLD大鼠模型,连续监测4~16周模型动物肝功能、脂质代谢、胰岛素抵抗及肝细胞凋亡在NAFLD进展过程中的变化情况及相互关系,为该模型在脂肪肝发病机制、脂肪肝治疗药物评价等方面的应用提供参考依据。方法 SD大鼠50只,除正常对照组外,其余动物饲喂高脂饲料,分别检测4,8,12,16周大鼠血清GLU、CHO、TG、HDL、LDL、GPT、GOT及胰岛素水平,肝脏组织切片进行病理学及细胞凋亡观察,进一步分析大鼠肝功能、脂质代谢、胰岛素抵抗及肝细胞凋亡对肝组织病理改变的影响。结果模型组大鼠4周后就出现肝功能损伤,脂质代谢紊乱、胰岛素抵抗,肝细胞凋亡8 W后明显增加,肝细胞脂变及炎症为肝组织病理变化的主要特征,且造模时间越长,病变程度越严重。结论经过高脂饲料的喂养,SD大鼠在4~16周内可形成病变程度逐步加重的NAFLD模型,肝功能损伤,脂质代谢紊乱及肝细胞凋亡是引起非酒精性脂肪肝中脂肪变性和炎症的重要因素,该模型可应用于脂肪肝治疗药物评价等方面。 相似文献
193.
几种旱生灌木种子萌发对干旱胁迫的响应 总被引:55,自引:5,他引:55
以不同渗透势的PEG(6 0 0 0 )溶液 (- 0 .3~ - 2 .7MPa)为模拟干旱胁迫条件 ,研究了柠条 (Caraganakorshinskii)、花棒 (Hedysarumscoparium)和白沙蒿 (Artemisiasphaerocephala)种子发芽、幼苗生长和累积吸水率对干旱胁迫的响应 ,讨论了参试种子发芽特性、初生根长度与幼苗建植成活率的关系 .结果表明 ,干旱胁迫下柠条发芽率最高 ,其次为花棒 ,白沙蒿最低 . - 0 .3~ - 0 .6MPa渗透势下白沙蒿发芽 10d的初生根长度显著大于花棒和柠条 (P <0 .0 5 ) ,三者的测量值依次为 7.9、4 .5和 3.1cm .干旱胁迫条件下参试种子发芽率与种子 72h累积吸水率均呈极显著的正相关 (P <0 .0 1) . 相似文献
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195.
Attia Shah Sadia Alam Muhammad Kabir Sajjad Fazal Adnan Khurshid Asia Iqbal Muhammad Mumtaz Khan Waqar Khan Abdul Qayyum Mubashar Hussain Ahmad El Askary Amal F. Gharib Basem H. Elesawy Yamin Bibi 《Saudi Journal of Biological Sciences》2022,29(5):3167
The acquisition of multi-drug resistance (MDR) genes by pathogenic bacterial bugs and their dispersal to different food webs has become a silent pandemic. The multiplied use of different antibacterial therapeutics during COVID-19 pandemic has accelerated the process among emerging pathogens. Wild migratory birds play an important role in the spread of MDR pathogens and MDR gene flow due to the consumption of contaminated food and water. Escherichia fergusonii is an emerging pathogen of family Enterobacteriaceae and commonly causes disease in human and animals. The present study focused on the isolation of E. fergusonii from blood, saliva, and intestine of selected migratory birds of the Hazara Division. The sensitivity of isolated strains was assessed against ten different antibiotics. The isolation frequency of E. fergusonii was 69%. In blood samples, a high rate of resistance was observed against ceftriaxone (80%) followed by ampicillin (76%) whereas, in oral and intestinal samples, ceftriaxone resistant strains were 56% and 57% while ampicillin resistance was 49% and 52% respectively. The overall ceftriaxone and ampicillin-resistant cases in all three sample sources were 71% and 65% respectively. In comparison to oral and intestinal samples, high numbers of ceftriaxone-resistant strains were isolated from the blood of mallard while ampicillin-resistant strains were observed in blood samples of cattle egrets. 16S rRNA-based confirmed strains of E. fergusonii were processed for detection of CTX-M and TEM-1 gene through Polymerase chain reaction (PCR) after DNA extraction. Hundred percent ceftriaxone resistant isolates possessed CTX-M and all ampicillin-resistant strains harbored TEM-1 genes. Amplified products were sequenced by using the Sanger sequencing method and the resulted sequences were checked for similarity in the nucleotide Database through the BLAST program. TEM-1 gene showed 99% and the CTX-M gene showed 98% similar sequences in the Database. The 16S rRNA sequence and nucleotide sequences for TEM-1 and CTX-M genes were submitted to Gene Bank with accession numbers , LC521304, LC521306 respectively. We posit to combat MDR gene flow among the bacterial pathogens across different geographical locations, regular surveillance of new zoonotic pathogens must be conducted. LC521307相似文献
196.
Waseem Ahmed Rafia Azmat Nabila Chendouh-Brahmi Rasheed Ahmed Saima Naz Abdul Qayyum Ahmad El Askary Amal F. Gharib Amani A. Alrehaili Nausad Ali 《Saudi Journal of Biological Sciences》2022,29(8):103351
Antibacterial drug-resistant strains are a serious problem of bacterial treatments nowadays and have a concern. The plant exacts of Adhatoda vasica and Calotropis procera are well-known for their role as antibiotic agents. The extraction of novel antibiotic compounds was done by HPLC-DAD, their yield is quantified by numerous solvents. The complete biological activity with antioxidants, bio-kinematicof four compounds of B-Sitosteryl linoleate, Myristyl diglucoside, D-Triglucopyranoside, and S- allylcysteine acids were studied. The supercritical fluid extraction techniques were the best strategies for higher yield, accuracy clarity, and inter, intra process of all four compounds. A. vasica and C. procera samples and investigated in six different solvents. D-Triglucopyranoside (13.81 ± 0.48%), Myristyl diglucoside (11.81 ± 0.41%), B- Sitosteryl linoleate (12.81 ± 0.48%), and s-allylcysteine acids (14.81 ± 0.31%) were higher. The design and action of compounds were applied to proper compartmental pharmacokinetic modelling for in-depth design understanding. The morphology and structure of bacterial cells with the extracted compounds upheld the permeability of cell membranes, membrane integrity, and membrane potential and lower the bacterial binding capacity the infectious index was measured in transmission electron microscopy (TEM) and their alteration process. Plants have well upheld the cellular permeability The toxicity test was performed on both extracted samples with concentrations (1, 0.4, and 0.8%). The areas under plasma half-life of compounds with their solubility, abortion level were higher in four compounds showed the potential of novel antibiotics. The novel medicinal plants used as antibiotics could be the best sources of infection control as a source of future medicines with antibacterial potential solving multidrug issues of bacteria in the world. 相似文献
197.
为解决过去保护修复工程只考虑单要素、单一类型生态系统的问题,我国于2016年开展了“山水林田湖草”生态修复工程,旨在通过整体、系统、综合的方法对各类生态系统进行统筹治理。然而,目前的工程治理中仍然存在对系统内部及系统间耦合概念理解不充分、系统耦合机制不明晰、对“尺度”的关注不足、缺少科学的分析方法等问题,制约了保护修复的成效。对此,首先将多个尺度下的耦合研究方法进行归纳总结,并以国家重点冰川水源涵养区及生物多样性保护优先区——疏勒河流域为例,将耦合方法用于分析要素间、自然生态系统间的耦合关系,最后基于该实例研究,提出多尺度耦合分析框架与“升尺度”保护修复模式,以期帮助相关决策者明晰“山水工程”中要素、系统间的耦合关系,增强治理的科学性与有效性,进而推进我国社会与环境的可持续发展。 相似文献
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199.
Diapausing Bombyx mori eggs were treated with 20-hydroxyecdysone as follows: a 30 minute immersion in bleaching water was followed by a 24-hour soaking in a 10?4 M solution of the hormone. Of the treated embryos 85% developed to some extent and 25% of them terminated their embryonic development. The efficiency of the treatment rapidly decreased when eggs were allowed to hibernate at 7°C in order to break diapause. 相似文献
200.
An impedance pump – also known as Liebau pump – is a simple valveless pump that operates based on the principles of wave propagation and reflection. It has been shown in embryonic zebrafish that a similar mechanism is responsible for the pumping action in the embryonic heart during the early stages before valve formation. Recent studies suggest that the cardiovascular system is designed to take advantage of wave propagation and reflection phenomena in the arterial network. In this study we report the results of an in-vitro study that examines the hypothesis that the adult human aorta acts as a passive pump based on Liebau effect. A hydraulic model with different compliant models of an artificial aorta was used for a series of in-vitro experiments. Our result indicates that wave propagation and reflection can result in a pumping mechanism in a compliant aorta. 相似文献