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701.
Yogesh Mishra Poonam Bhargava Riti Thapar Ashish Kumar Srivastava Lal Chand Rai 《World journal of microbiology & biotechnology》2008,24(12):2997-3004
This study provides first hand comparative account of growth and antioxidative defense system of the wild type, Cu2+ and temperature treated wild type and acclimated strains of Anabaena doliolum Bharadwaja against Cu2+ and high temperature. The acclimated strains showed perceptible growth at 250 μM Cu2+ and 47°C temperatures, respectively. In contrast to this the wild type strain on exposure to 50 μM Cu2+ and 47°C temperature depicted almost complete inhibition of growth. However, the peroxide content was significantly higher
in the acclimated strains than the wild type. Superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and
glutathione reductase (GR) showed maximum activity at high temperature followed by Cu2+ acclimated and minimum in the wild type strains. The ascorbate (ASC) and glutathione (GSH) contents were increased by 2.3
and 43.3, and 15.5 and 36.5-fold in Cu2+ and 47°C acclimated strains, respectively. However, when the wild type strain was subjected to Cu2+ and temperature all antioxidative enzymes except SOD showed inhibition of their activity. In case of wild type the GSH content
was inhibited by 0.39-fold at 50 μM Cu2+ but the ASC content registered increase by 2 and 2.7-fold on subjecting to Cu2+ and temperature, respectively. Thus increased activity of enzymatic antioxidants as well as accumulation of ascorbate and
glutathione in both the acclimated strains suggests that enzymatic and non-enzymatic antioxidants help in the acclimation
of A. doliolum Bharadwaja against Cu2+ and high temperature. However, inhibition of antioxidative defense system of wild type under Cu2+ and heat stress appears to be the reason for its non survival. In view of the appreciable increase in the level of antioxidants
as well as greater inhibition of specific growth rate in temperature than Cu2+ acclimated strains, temperature (47°C) is proposed to be is more deleterious to the organism than copper (250 μM). 相似文献
702.
ZHANG Xiansheng LIU Zaixin ZHAO Qizu CHANG Huiyun & XIE QinggeDepartment of Virology Lanzhou Veterinary Research Institute Chinese Academy of Agricultural Sciences 《中国科学:生命科学英文版》2004,47(1):74-81
The complete nucleotide sequence of genomic RNA of foot and mouth disease virus (FMDV) strain China/99 from infected bovine tongue epithelium is presented. The nucleotide sequence extending from the 5' end of the genomic RNA to the 5' end of poly (A) tail contains 8173 nucleotides (nt). Its open reading frame, which encodes a single polypeptide of 2332 amino acids, encompasses 6999 nt starting from the initiation codon AUG and terminating at the UAA codon 93 bases upstream from the 5' end of poly (A) tract. The 5' untranslated region (UTR) is composed of 1081 nt. The consensus of the 1d gene of FMDV strain China/99 compared with that of UKG/6/2001, UKG/12/2001, China/99HN4 and China/3/Tibet is over 97%. The result showed the stains belong to the members of the Pan-Asia family. There is a remarkable differentiation in the function-unknown (FUR), p2 and p3 regions between FMDV isolates from infected cattle and swine, especially in 3a gene. No deletion was found in genes /, 1a, 1b, 2a, 2c, 3b, and 3d. Thes 相似文献
703.
目的:建立近交系小鼠同种异品系颈部心脏移植模型.方法:用袖套法进行小鼠颈部心脏移植,选BALB/c小鼠(供体)和用C57小鼠(受体),进行同种异品系移植25例.结果:供心热缺血2~5 min,冷缺血20~25 min,手术总时间为60~70 min,手术成功率为96%.移植心脏平均存活期为(8.44±1.25)d,n=12.结论:运用改进的套管技术建立小鼠颈部心脏移植模型是一种成功率高而且可靠的方法,可用于移植免疫方面的研究. 相似文献
704.
Aims: To isolate the biologically active fraction of the lipopeptide biosurfactant produced by a marine Bacillus circulans and study its antimicrobial potentials. Methods and Results: The marine isolate B. circulans was cultivated in glucose mineral salts medium and the crude biosurfactant was isolated by chemical isolation method. The crude biosurfactants were solvent extracted with methanol and the methanol extract was subjected to reverse phase high‐performance liquid chromatography (HPLC). The crude biosurfactants resolved into six major fractions in HPLC. The sixth HPLC fraction eluting at a retention time of 27·3 min showed the maximum surface tension‐reducing property and reduced the surface tension of water from 72 mNm?1 to 28 mNm?1. Only this fraction was found to posses bioactivity and showed a pronounced antimicrobial action against a panel of Gram‐positive and Gram‐negative pathogenic and semi‐pathogenic micro‐organisms including a few multidrug‐resistant (MDR) pathogenic clinical isolates. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of this antimicrobial fraction of the biosurfactant were determined for these test organisms. The biosurfactant was found to be active against Gram‐negative bacteria such as Proteus vulgaris and Alcaligens faecalis at a concentration as low as 10 μg ml?1. The biosurfactant was also active against methicillin‐resistant Staphylococcus aureus (MRSA) and other MDR pathogenic strains. The chemical identity of this bioactive biosurfactant fraction was determined by post chromatographic detection using thin layer chromatography (TLC) and also by Fourier transform infrared (FTIR) spectroscopy. The antimicrobial HPLC fraction resolved as a single spot on TLC and showed positive reaction with ninhydrin, iodine and rhodamine‐B reagents, indicating its lipopeptide nature. IR absorption by this fraction also showed similar and overlapping patterns with that of other lipopeptide biosurfactants such as surfactin and lichenysin, proving this biosurfactant fraction to be a lipopeptide. The biosurfactant did not show any haemolytic activity when tested on blood agar plates, unlike the lipopeptide biosurfactant surfactin produced by Bacillus subtilis. Conclusions: The biosurfactant produced by marine B. circulans had a potent antimicrobial activity against Gram‐positive and Gram‐negative pathogenic and semi‐pathogenic microbial strains including MDR strains. Only one of the HPLC fractions of the crude biosurfactants was responsible for its antimicrobial action. The antimicrobial lipopeptide biosurfactant fraction was also found to be nonhaemolytic in nature. Significance and impact of the study: This work presents a nonhaemolytic lipopeptide biosurfactant produced by a marine micro‐organism possessing a pronounced antimicrobial action against a wide range of bacteria. There is a high demand for new antimicrobial agents because of the increased resistance shown by pathogenic micro‐organisms against the existing antimicrobial drugs. This study provides an insight into the search of new bioactive molecules from marine micro‐organisms. 相似文献
705.
To evaluate the importance of searching new naturally occurring strains to raise yields in mushroom production, eight wild and four commercial strains of Agrocybe cylindracea were cultivated on wheat straw. The highest biological efficiencies (BE) (54.5-72.4%) were obtained with three wild and two commercial strains when cultured on non-supplemented wheat straw. Rolled oats or soybean flour supplementation were tested using three selected strains, increasing BEs up to 1.2, 0.5 and 0.7-fold, respectively. This effect of supplementation was stronger in the Asiatic wild strain, yielding up to 41.1 and 30% more than the two other strains with rolled oats and soybean flour, respectively. The Asiatic wild strain cultivated with soybean flour supplementation achieved an average biological efficiency of 179%, to our knowledge, the highest reported for this species. These results show the importance of searching for new naturally occurring strains in combination with supplemented wheat straw substrate for raising yields in A. cylindracea cultivation. 相似文献
706.
Genetic dissection of quantitative trait locus for ethanol sensitivity in long- and short-sleep mice
Bennett B Carosone-Link P Beeson M Gordon L Phares-Zook N Johnson TE 《Genes, Brain & Behavior》2008,7(6):659-668
Interval-specific congenic strains (ISCS) allow fine mapping of a quantitative trait locus (QTL), narrowing its confidence interval by an order of magnitude or more. In earlier work, we mapped four QTL specifying differential ethanol sensitivity, assessed by loss of righting reflex because of ethanol (LORE), in the inbred long-sleep (ILS) and inbred short-sleep (ISS) strains, accounting for approximately 50% of the genetic variance for this trait. Subsequently, we generated reciprocal congenic strains in which each full QTL interval from ILS was bred onto the ISS background and vice versa. An earlier paper reported construction and results of the ISCS on the ISS background; here, we describe this process and report results on the ILS background. We developed multiple ISCS for each Lore QTL in which the QTL interval was broken into a number of smaller intervals. For each of the four QTL regions (chromosomes 1, 2, 11 and 15), we were successful in reducing the intervals significantly. Multiple, positive strains were overlapped to generate a single, reduced interval. Subsequently, this reduced region was overlaid on previous reductions from the ISS background congenics, resulting in substantial reductions in all QTL regions by approximately 75% from the initial mapping study. Genes with sequence or expression polymorphisms in the reduced intervals are potential candidates; evidence for these is presented. Genetic background effects can be important in detection of single QTL; combining this information with the generation of congenics on both backgrounds, as described here, is a powerful approach for fine mapping QTL. 相似文献
707.
就维生素C微生物一步发酵方法进行了探索,构建了酮古龙酸杆菌、氧化葡萄糖酸杆菌和芽孢杆菌三菌混菌一步发酵的方法。研究发现,植物内生芽孢杆菌可以与酮古龙酸杆菌配合,促进酮古龙酸杆菌生长和产酸。在有山梨醇存在的条件下酮古龙酸杆菌及其伴生菌能够快速地生长增殖,植物内生芽孢杆菌在发酵的10h中不断消耗山梨醇。5L的发酵罐中,酮古龙酸杆菌、氧化葡萄糖酸杆菌和植物内生芽孢杆菌三菌混菌一步发酵在恒定的30℃温度,600r/min搅拌速度和1.5vvm通气条件下,补料发酵过程中醇酸质量转化率达到了81.89%,在分批发酵过程中,醇酸质量转化率达到了87.90%,进一步优化了维生素C生产工艺。 相似文献
708.
709.
One thousand six hundred and twenty yeast isolates were obtained from 54 spontaneous fermentations performed from grapes collected in 18 sampling sites of three vineyards (Vinho Verde Wine Region in northwest Portugal) during the 2001-2003 harvest seasons. All isolates were analyzed by mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) and a pattern profile was verified for each isolate, resulting in a total of 297 different profiles, that all belonged to the species Saccharomyces cerevisiae. The strains corresponding to seventeen profiles showed a wider temporal and geographical distribution, being characterized by a generalized pattern of sporadic presence, absence and reappearance. One strain (ACP10) showed a more regional distribution with a perennial behavior. In different fermentations ACP10 was either dominant or not, showing that the final outcome of fermentation was dependent on the specific composition of the yeast community in the must. Few of the grape samples collected before harvest initiated a spontaneous fermentation, compared to the samples collected after harvest, in a time frame of about 2 weeks. The associated strains were also much more diversified: 267 patterns among 1260 isolates compared to 30 patterns among 360 isolates in the post- and pre-harvest samples, respectively. Fermenting yeast populations have never been characterized before in this region and the present work reports the presence of commercial yeast strains used by the wineries. The present study aims at the development of strategies for the preservation of biodiversity and genetic resources as a basis for further strain development. 相似文献
710.
Mauritius is one of the largest world producers of Anthurium cut flowers but outbreaks of bacterial blight have never been reported on the island. This work was about the characterisation and identification of bacterial strains isolated from Anthurium andreanum, Dieffenbachia maculata and Aglaonema simplex in Mauritius. Fifteen strains, that showed the morphological properties of Xanthomonas on conventional media, were tested on two semi-selective media (Esculin-trehalose and cellobiose-starch). ELISA tests using a panel of monoclonal antibodies were carried out and three out of 15 strains reacted with a Xanthomonas-specific monoclonal antibody (MAb XII). Analysis using four sets of ribosomal primers revealed that the same three Mauritius strains shared conserved PCR products with reference xanthomonads including virulent strains of Xanthomonas axonopodis pv. dieffenbachiae (Xad). BIOLOG tests and the Sherlock Microbial Identification system (MIDI) identified these three new strains at the species level as X. axonopodis. The complementary tests that were carried out clearly confirmed that the three strains are xanthomonads and, moreover, a DNA probe which showed specificity to Xad strains suggested that the three Mauritius strains are non-virulent forms of the pathogen causing Anthurium blight. 相似文献