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991.
3D-OCP--一种大中型野生动物家域研究模型   总被引:4,自引:0,他引:4  
利用全球定位系统(GPS)的三维定位能力和电子计算机处理复杂运算的能力,通过对动物活动痕迹和地理标志精确定位,并利用大地测量学的方法,将地球球面坐标系转化为高斯-吕格平面坐标系后,建立了一种反映野生动物实际生活环境的三维空间家域模型,并开发了计算三维空间家域面积的计算机软件3D-OCP。  相似文献   
992.
本文主要记述了辽宁省朝阳市龙城区马山洞发现的食肉类化石。堆积物的上部主要为颗粒细小的砂质黏土, 而下部主要为直径较大的角砾。2007年出土的食肉目化石有: 似浣熊貉(Nyctereutes procyonoides)、赤狐(Vulpes vulpes)、狗獾(Meles meles)、黄鼬(Mustela sibirica)、中华猫(Felis chinensis)和疑似虎(Panthera tigris)?。其中前5个种在形态上与现生种类非常接近; 而最后一个种除与现生虎比较接近外, 与现生狮子也有一定的相似性。  相似文献   
993.
不同方法提取的荷叶挥发油化学成分分析   总被引:12,自引:0,他引:12  
采取超临界CO2萃取和水蒸气蒸馏提取荷叶挥发油,利用GC-MS对它们进行了定性、定量分析。结果表明这两种方法提取荷叶挥发油的化学成分及含量皆有很大差别。超临界CO2萃取的荷叶挥发油更具天然性,超临界CO2萃取法为提取荷叶挥发油的理想方法。  相似文献   
994.
A novel direct readout colorimetric optical glucose sensor strip was constructed based on a three-layer film, including a green-emitted CdTe/CdS quantum dots (QDs) layer as a stable color background, a red-fluorescent platinum-porphyrin oxygen-sensing layer and a glucose oxidase layer. The sensor achieved high resolution (up to 0.2 mmol L−1) glucose determination with a detection range from 0 to 3.0 mmol L−1. A “glucose ruler” which acts as a glucose standard colorimetric card was obtained. Glucose concentration could easily be directly readout using the “glucose ruler”, which made the glucose determination rapid, convenient and easy. The effects of pH, salinity and temperature were systematically investigated. The prepared sensor was finally applied for glucose sample analysis, compared with the “glucose ruler”, accurate results could be directly readout.  相似文献   
995.
国内护士工作满意度研究文献分析   总被引:5,自引:0,他引:5  
目的:了解我国护士工作满意度的研究现状。方法:采用文献分析法对我国1997~2005年有关护士工作满意度研究的论文25篇进行分析。结果:近年来学者们愈加关注对护士工作满意度的研究,研究的角度各有不同,研究论文的质量也有所提高,但很多方面还存在不足。结论:国内关于护士工作满意度的研究尚集中在调查性研究层次,干预性研究还未充分开展,鉴于护士工作满意度对护士自身以及护理质量的重要影响,开展干预性研究势在必行。  相似文献   
996.
In this work, severe acute respiratory syndrome associated coronavirus (SARS-CoV) genome BJ202 (AY864806) was completely sequenced. The genome was directly accessed from the stool sample of a patient in Beijing. Comparative genomics methods were used to analyze the sequence variations of 116 SARS-CoV genomes (including BJ202) available in the NCBI Gen-Bank. With the genome sequence of GZ02 as the reference, there were 41 polymorphic sites identified in BJ202 and a total of 278 polymorphic sites present in at least two of the 116 genomes. The distribution of the polymorphic sites was biased over the whole genome. Nearly half of the variations (50.4%, 140/278) clustered in the one third of the whole genome at the 3′ end (19.0 kb-29.7 kb). Regions encoding Orf10-11, Orf3/4, E, M and S protein had the highest mutation rates. A total of 15 PCR products (about 6.0 kb of the genome) including 11 fragments containing 12 known polymorphic sites and 4 fragments without identified polymorphic sites were cloned and sequenced. Results showed that 3 unique polymorphic sites of BJ202 (positions 13 804, 15 031 and 20 792) along with 3 other polymorphic sites (26 428, 26 477 and 27 243) all contained 2 kinds of nucleotides. It is interesting to find that position 18379 which has not been identified to be polymorphic in any of the other 115 published SARS-CoV genomes is actually a polymorphic site. The nucleotide composition of this site is A (8) to G (6). Among 116 SARS-CoV genomes, 18 types of deletions and 2 insertions were identified. Most of them were related to a 300 bp region (27 700-28 000) which encodes parts of the putative ORF9 and ORF10-11. A phylogenetic tree illustrating the divergence of whole BJ202 genome from 115 other completely sequenced SARS-CoVs was also constructed. BJ202 was phylogeneticly closer to BJ01 and LLJ-2004.  相似文献   
997.
结香的组织培养和快速繁殖   总被引:2,自引:0,他引:2  
1 植物名称 结香(Edgeworthia chrysantha Lindl.)。  相似文献   
998.
Growing evidence suggests that Ca(2+) overload is one of the major contributors of myocardial ischemia/reperfusion-induced injury. Since Frizzled-2 receptor, a seven transmembrane protein, transduces downstream signaling by specialized binding of Wnt5a to increase intracellular Ca(2+) release, this work aimed to investigate the effect of Frizzled-2 on Ca(2+) accumulation in H9c2 cells, which were subjected to hypoxia/reoxygenation to mimic myocardial ischemia/reperfusion. After exposing H9c2 cells to hypoxia/reoxygenation, we observed higher expression of Frizzled-2 and Wnt5a as compared to control group cells. Hypoxia/reoxygenation-induced intracellular Ca(2+) accumulation approached that of cells transfected with frizzled-2 plasmid. In cells treated with RNAi specifically designed against frizzled-2, intracellular Ca(2+) in both hypoxia/reoxygenation-treated cells and plasmid-treated cells were decreased. Rats that underwent ischemia/reperfusion injury exhibited increased intracellular Ca(2+) with high expression levels of Frizzled-2 and Wnt5a as compared to the sham group. Our data indicates that upon binding to Wnt5a, increased Frizzled-2 expression after hypoxia/reoxygenation treatment activated intracellular calcium release in H9c2 cells. Our findings provide a new perspective in understanding calcium overload in myocardial ischemia/reperfusion.  相似文献   
999.
The effects of potassium cyanide (KCN) pretreatment on the response of cucumber (Cucumis sativus L.) plants to salt, polyethylene glycol (PEG) and cold stress were investigated in the present study. Here, we found that KCN pretreatment improved cucumber seedlings tolerance to stress conditions with maximum efficiency at a concentration of 20 µM. The results showed that pretreatment with 20 µM KCN alleviated stress‐induced oxidative damage in plant cells and clearly induced the activity of alternative oxidase (AOX) and the ethylene production. Furthermore, the structures of thylakoids and mitochondria in the KCN‐pretreated seedlings were less damaged by the stress conditions, which maintained higher total chlorophyll content, photosynthetic rate and photosystem II (PSII) proteins levels than the control. Importantly, the addition of the AOX inhibitor salicylhydroxamic acid (1 mm ; SHAM) decreased plant resistance to environmental stress and even compromised the cyanide (CN)‐enhanced stress tolerance. Therefore, our findings provide a novel role of CN in plant against environmental stress and indicate that the CN‐enhanced AOX might contribute to the reactive oxygen species (ROS) scavenging and the protection of photosystem by maintaining energy charge homoeostasis from chloroplast to mitochondria.  相似文献   
1000.
GBDB在线数据库是一个基于网络、数据库和GIS技术开发的古生物学和地层学数字化科研平台。GBDB的文献数据指示了GBDB中绝大多数科学数据的来源。经过多年的探索和不断改进,GBDB的文献数据库在结构上日益完善,其中细分了8种类型的文献,支持DOI链接和对在线全文数据库的指向,其导出功能支持12种常用期刊的参考文献格式。文献数据库的完善是一个长期积累的过程,需要通过众多学者的参与,才能最终建成一个高质量的科学文献数据库。截止2012年2月,GBDB的文献数据库已经收集了与古生物学和地层学相关的各类文献条目44310条。初步的统计显示,自1900年以来,古生物学和地层学相关文献的数量基本保持增长的态势。其中,1910—1959年,基本处于平稳的上升期,仅在1940—1949年间有一小幅度的下降,可能与第二次世界大战的影响相关;此后,文献数量快速上升,在上世纪90年代达到7439篇,这与同期国内外传统古生物学和地层学研究的繁盛相对应。但进入二十一世纪后的十年里,文献数量呈现明显的下降,有两种可能原因,一是较晚发表的文献,其传播速度与其发表年限呈负相关,老文献随时间流逝传播越来越广,因此更容易被数据库收录到;另一种可能则是近年来人们越来越多地重视各种前沿和热点领域的研究,而很少开展野外地质考察、剖面描述、地层划分与对比、化石描述、系统古生物学等传统领域的基础工作。  相似文献   
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