全文获取类型
收费全文 | 1375篇 |
免费 | 41篇 |
国内免费 | 105篇 |
出版年
2023年 | 4篇 |
2022年 | 18篇 |
2021年 | 16篇 |
2020年 | 26篇 |
2019年 | 16篇 |
2018年 | 15篇 |
2017年 | 26篇 |
2016年 | 33篇 |
2015年 | 51篇 |
2014年 | 60篇 |
2013年 | 75篇 |
2012年 | 55篇 |
2011年 | 118篇 |
2010年 | 97篇 |
2009年 | 98篇 |
2008年 | 125篇 |
2007年 | 102篇 |
2006年 | 100篇 |
2005年 | 97篇 |
2004年 | 74篇 |
2003年 | 54篇 |
2002年 | 35篇 |
2001年 | 5篇 |
2000年 | 15篇 |
1999年 | 21篇 |
1998年 | 18篇 |
1997年 | 17篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 15篇 |
1993年 | 15篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 7篇 |
1989年 | 5篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 9篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1981年 | 10篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1950年 | 1篇 |
排序方式: 共有1521条查询结果,搜索用时 15 毫秒
951.
952.
Ro S Park C Jin J Sanders KM Yan W 《Biochemical and biophysical research communications》2006,351(3):756-763
Recent cloning efforts have identified hundreds of thousands of small RNAs including micro RNAs (miRNAs), Piwi-interacting RNAs (piRNAs), and small nucleolar RNAs (snoRNAs). These non-coding small RNAs need to be further validated and characterized by detecting and quantifying their expression in different tissues and during different developmental courses. A simple, accurate, and sensitive method for small RNA expression profiling is in high demand. Here, we report such a PCR-based method. 相似文献
953.
Selection of promising fungal biological control agent of the western flower thrips Frankliniella occidentalis (Pergande) 总被引:1,自引:0,他引:1
Niassy S Maniania NK Subramanian S Gitonga LM Mburu DM Masiga D Ekesi S 《Letters in applied microbiology》2012,54(6):487-493
Aims: Larval stages of Frankliniella occidentalis are known to be refractory to fungal infection compared with the adult stage. The objective of this study was to identify promising fungal isolate(s) for the control of larval stages of F. occidentalis. Methods and Results: Ten isolates of Metarhizium anisopliae and eight of Beauveria bassiana were screened for virulence against second‐instar larvae of F. occidentalis. Conidial production and genetic polymorphism were also investigated. Metarhizium anisopliae isolates ICIPE 7, ICIPE 20, ICIPE 69 and ICIPE 665 had the shortest LT50 values of 8·0–8·9 days. ICIPE 69, ICIPE 7 and ICIPE 20 had the lowest LC50 values of 1·1 × 107, 2·0 × 107 and 3·0 × 107 conidia ml?1, respectively. Metarhizium anisopliae isolate ICIPE 69 produced significantly more conidia than M. anisopliae isolates ICIPE 7 and ICIPE 20. Internally transcribed spacers sequences alignment showed differences in nucleotides composition, which can partly explain differences in virulence. Conclusion: These results coupled with the previous ones on virulence and field efficacy against other species of thrips make M. anisopliae isolate ICIPE 69 a good candidate. Significance and Impact of the Study: Metarhizium anisopliae isolate ICIPE 69 can be suggested for development as fungus‐based biopesticide for thrips management. 相似文献
954.
955.
为了解斑马鱼胚胎发育过程中FGF3基因的时空性表达情况,并探讨其对胚胎发育的调控作用,该研究分别提取2,4,8,12,24,36,48,72hpf斑马鱼胚胎的总RNA,经逆转录成cDNA,实时荧光定量PcR检测FGF3基因mRNA表达量;扩增FGF3基因特异片段,构建pGEM-T/FGF3基因片段重组质粒,经克隆及测序验证后,合成地高辛标记的反义RNA探针,以整体原位杂交法检测斑马鱼胚胎FGF3基因的空间性表达。结果显示:FGF3P基因在2hp胚胎就有表达,并持续至胚胎孵化,12hpf胚胎FGF3表达量达到高峰(P〈0.01);胚胎发育过程中心表达部位以头、尾、咽弓为主。由此得出结论,FGF3主要在胚胎发育早期表达,其表达可能与胚胎脑、眼、耳、咽弓及尾部器官的发育调控有关。 相似文献
956.
鳕鱼成分的实时荧光PCR检测方法 总被引:1,自引:0,他引:1
研究建立了鳕鱼成分的实时荧光PCR检测方法。依据鳕鱼的16S rRNA基因序列设计一对PCR引物及探针,对12种鳕鱼样品和71种非鳕鱼动植物样品进行实时荧光PCR检测,结果显示,只有12种鳕鱼样品产生荧光信号,其他非鳕鱼样品均不产生荧光信号,实验表明此方法具有特异性,其检测限为0.01 ng/μl鳕鱼DNA和0.01%鳕鱼肉粉。对市售的鳕鱼样品进行实际样品检测,均能很好地检出鳕鱼成分。此法特异性强,灵敏度高,可作为鳕鱼成分鉴定的检测方法。 相似文献
957.
Endoplasmic reticulum (ER) stress is increasingly recognized as an important mechanism in a wide range of diseases including
cystic fibrosis, alpha-1 antitrypsin deficiency, Parkinson's and Alzheimer's disease. Therefore, there is an increased need
for reliable and quantitative markers for detection of ER stress in human tissues and cells. Accumulation of unfolded or misfolded
proteins in the endoplasmic reticulum can cause ER stress, which leads to the activation of the unfolded protein response
(UPR). UPR signaling involves splicing of X-box binding protein-1 (XBP1) mRNA, which is frequently used as a marker for ER
stress. In most studies, the splicing of the XBP1 mRNA is visualized by gel electrophoresis which is laborious and difficult
to quantify. In the present study, we have developed and validated a quantitative real-time RT-PCR method to detect the spliced
form of XBP1 mRNA. 相似文献
958.
Jiong Chen Hai Q. Wu Yu H. Shi Chang H. Li Ming Y. Li 《Comparative biochemistry and physiology. Part D, Genomics & proteomics》2009,4(4):263-267
As the life cycle of ayu spans river, brackish and seawater environments, it would be a suitable fish model for studying the responses to salinity changes in aquatic animals. We investigated the effect of salinity on trunk kidney proteome in ayu (Plecoglossus altivelis) using two-dimensional gel electrophoresis and mass spectrometry. The proteins involved in the process of energy metabolism, biosynthesis, DNA methylation and cell differentiation were mainly affected, and 10 significantly changed proteins were identified. Our result showed that isocitrate dehydrogenase (ICD), pyruvate dehydrogenase (E1), O-glycosyl hydrolase, mitochondrial precursor of ATP synthase subunit beta, mitochondrial ferrtin (MtF), retinol binding protein (RBP) were down-regulated, whereas aldehyde dehydrogenase, cytokeratin 1, S-adenosylhomocysteine hydrolase, Cys-Met metabolism PLP-dependent enzyme were up-regulated when ayu transferred from freshwater to brackish water. Partial coding sequences of E1, ICD, MtF and RBP genes were determined, and the effects of salinity on their mRNA expression in ayu trunk kidney were tested by real-time PCR subsequently. Their possible direct or indirect roles in the adaptation of ayu to salinity are discussed. 相似文献
959.
Monika Kern Stephan Bhm Ludwig Deml Hans Wolf Udo Reischl Hans Helmut Niller 《Journal of microbiological methods》2009,79(2):189-193
Impurities in complex biological samples that persist through nucleic acid preparation can inhibit PCR or reduce the sensitivity and efficiency of PCR amplification and thus affect reliable results in PCR diagnostics. To obtain information on the incidence of inhibition events and on the magnitude of the loss of sensitivity, respectively, we devised a relative inhibition assay and examined 100 samples from patients with respiratory tract infections. As a reference, samples were spiked with Legionella (L.) pneumophila. Detection was by standard nucleic acid purification and subsequent real-time PCR. By comparing the crossing points of the fluorescent curves to those of an L. pneumophila standard dilution series, we were able to quantify the respective degrees of inhibition into several categories. We found complete inhibition in 2% of the samples. 12% were not reliably detected. 65% of the tested samples showed moderate to strong inhibition, but were still reliably detected, whereas in 21% of the samples no inhibition was observed. Except for a significantly higher inhibition in tracheal aspirates than in BAL samples, the degree of inhibition did not correlate with the physical properties of the respective sample. The relative inhibition assay established an unexpectedly broad distribution of the inhibition-degrees in inflammatory respiratory materials. 相似文献
960.
Sequence-specific bacterial growth inhibition by peptide nucleic acid targeted to the mRNA binding site of 16S rRNA 总被引:1,自引:0,他引:1
Masashi Hatamoto Kazufumi Nakai Akiyoshi Ohashi Hiroyuki Imachi 《Applied microbiology and biotechnology》2009,81(6):1161-1168
To compare oxidative dissolution rates of chalcopyrite by different consortia of moderately thermophilic acidophiles, various
defined mixed cultures of three bacteria Acidithiobacillus caldus s2, Leptospirillum ferriphilum YSK, and Sulfobacillus sp. LN and one archaeon Ferroplasma thermophilum L1 were studied in batch shake flask cultures incubated at 45 °C. Chalcopyrite dissolution was determined by measuring variations
of soluble copper, ferric iron, and pH. Microbial population dynamics involved in bioleaching process were monitored using
real-time quantitative polymerase chain reaction (PCR) technology. The complex consortia containing both chemoautotrophic
(L. ferriphilum and At. caldus) and chemomixotrophic (Sulfobacillus LN and F. thermophilum) moderate thermophiles were found to be the most efficient in all of those tested. Mutualistic interactions between physiologically
distinct moderately thermophilic acidophiles, involving transformations of iron and sulfur and transfer of organic compound,
were considered to play a critical role in promoting chalcopyrite dissolution. The real-time PCR assay was reliable to analyze
population dynamics of moderate thermophiles in bioleaching systems, and the analysis results were consistent with physiological
characteristics of these strains. 相似文献