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51.
52.
Molecular dynamic simulations of systems of single-walled carbon nanotubes (CNTs) in liquid crystalline solvents were performed, in order to investigate the effect of the molecular structure and phase of the liquid crystal (LC) on the interactions between the CNTs. Three different LC molecules (5CB, 8CB and 5CF) were considered in our study. Our results with 5CB and 8CB suggest that increasing the chain length of the hydrophobic part of the LC molecule by three carbon atoms is insufficient to decrease the tendency for the CNTs to aggregate in the LCs. Additionally, varying the phase of the LC is also insufficient to decrease the aggregation tendency of the CNTs. However, simulations with 5CF (which has fluorine atoms in the head group of the LC molecule) suggest that this LC solvent can decrease the tendency of the CNTs to aggregate. This study is relevant to assist experimentalists with the development of high-quality dispersions of large concentrations of CNTs in the LCs. 相似文献
53.
Gisele M. S. Ouedraogo Güler Demirbas-Uzel Jean-Baptiste Rayaisse Geoffrey Gimonneau Astan C. Traore Antonios Avgoustinos Andrew G. Parker Issa Sidibe Anicet G. Ouedraogo Amadou Traore Bale Bayala Marc J. B. Vreysen Kostas Bourtzis Adly m. M. Abd-Alla 《BMC microbiology》2018,18(1):153
Background
Tsetse flies are vectors of African trypanosomes, protozoan parasites that cause sleeping sickness (or human African trypanosomosis) in humans and nagana (or animal African trypanosomosis) in livestock. In addition to trypanosomes, four symbiotic bacteria Wigglesworthia glossinidia, Sodalis glossinidius, Wolbachia, Spiroplasma and one pathogen, the salivary gland hypertrophy virus (SGHV), have been reported in different tsetse species. We evaluated the prevalence and coinfection dynamics between Wolbachia, trypanosomes, and SGHV in four tsetse species (Glossina palpalis gambiensis, G. tachinoides, G. morsitans submorsitans, and G. medicorum) that were collected between 2008 and 2015 from 46 geographical locations in West Africa, i.e. Burkina Faso, Mali, Ghana, Guinea, and Senegal.Results
The results indicated an overall low prevalence of SGHV and Wolbachia and a high prevalence of trypanosomes in the sampled wild tsetse populations. The prevalence of all three infections varied among tsetse species and sample origin. The highest trypanosome prevalence was found in Glossina tachinoides (61.1%) from Ghana and in Glossina palpalis gambiensis (43.7%) from Senegal. The trypanosome prevalence in the four species from Burkina Faso was lower, i.e. 39.6% in Glossina medicorum, 18.08%; in Glossina morsitans submorsitans, 16.8%; in Glossina tachinoides and 10.5% in Glossina palpalis gambiensis. The trypanosome prevalence in Glossina palpalis gambiensis was lowest in Mali (6.9%) and Guinea (2.2%). The prevalence of SGHV and Wolbachia was very low irrespective of location or tsetse species with an average of 1.7% for SGHV and 1.0% for Wolbachia. In some cases, mixed infections with different trypanosome species were detected. The highest prevalence of coinfection was Trypanosoma vivax and other Trypanosoma species (9.5%) followed by coinfection of T. congolense with other trypanosomes (7.5%). The prevalence of coinfection of T. vivax and T. congolense was (1.0%) and no mixed infection of trypanosomes, SGHV and Wolbachia was detected.Conclusion
The results indicated a high rate of trypanosome infection in tsetse wild populations in West African countries but lower infection rate of both Wolbachia and SGHV. Double or triple mixed trypanosome infections were found. In addition, mixed trypanosome and SGHV infections existed however no mixed infections of trypanosome and/or SGHV with Wolbachia were found.54.
A rapid cold hardening process is reported in first instar larvae of Frankliniella occidentalis. When larvae are transferred directly from 20 degrees C to -11.5 degrees C for 2h there is 78% mortality, whereas exposure to 0 degrees C for 4h prior to transfer to -11.5 degrees C reduces mortality to 10%. The response can also be induced by exposure to 5 degrees C for 4h or by gradual cooling at rates between 0.1 and 0.5 degrees C min(-1.) The acquired cold tolerance is transient and is rapidly lost (after 1h at 20 degrees C). Rapid cold hardening extends survival times at -11.5 degrees C and depresses lethal temperatures in short (2h) exposures. Rearing at 15 degrees C (12L:12D), (a cold acclimation regime for F. occidentalis), does not protect against the cold shock induced by direct transfer to -11.5 degrees C (which rapid cold hardening does) but does extend survival time at -5 degrees C (i.e. increased chill tolerance) whilst rapid cold hardening does not. The rapid and longer term cold hardening responses in F. occidentalis therefore appear to have different underlying mechanisms. 相似文献
55.
Human fibrinogen was treated with thrombin in the presence of fibrinoligase (Factor XIIIa) and calcium ion at pH 8.5, ionic strength 0.45, and the ensuing polymerization was interrupted at various time intervals (t) both before and after the clotting time (tc) by solubilization with a solution of sodium dodecyl sulfate and urea. Aliquots of the solubilized protein were subjected to gel electrophoresis on polyacrylamide gels after disulfide reduction by dithiothreitol and on agarose gels without reduction. The degree of γ-γ ligation was determined from the former. The latter provided the size distribution of ligated end-to-end sequences produced by splitting the ligated staggered overlapped oligomers down the middle, for degrees of polymerization, x, from 1 to 10. Addition of fibrinoligase (in which the activating thrombin had been inhibited by p-nitrophenyl-p′-guanidinobenzoate, NPGB) to Kabi fibrinogen showed the presence of small amounts of ligatable oligomers. Addition of fibrinoligase to a polymerizing mixture in which the action of thrombin had been stopped before clotting by NPGB produced the same distribution of ligated end-to-end sequences that was obtained when fibrinoligase was originally present, at least for reaction times up to 0.7 of the clotting time. The kinetics of γ-γ ligation by fibrinoligase acting on a polymerized mixture stabilized by NPGB were followed. The reaction was first order in the concentration of ligatable γ-γ junctions and the initial velocity was proportional to the enzyme concentration. The time evolution of size distribution of ligated end-to-end sequences agreed with a theory based on random ligation of ligatable junctions. 相似文献
56.
Craig A. Williams Peter Bale 《European journal of applied physiology and occupational physiology》1998,77(3):271-277
Previous research has often used correlations as a statistical method to show agreement; however, this is not a valid use
of the statistic. The purpose of this study was to investigate the bias and limits of agreement for three methods of estimating
percentage body fat for 117 male and 114 female university athletes: hydrodensitometry (HYD), bioelectrical impedance (BIA)
and skinfold calipers (SKF). The mean (SD) percentage body fat for males as assessed by HYD, BIA and SKF methods, respectively,
were 13.2 (3.3)%, 14.1 (3.3)% and 13.0 (3.2)%. Female body fat measurements were 22.5 (3.9)%, 23.7 (4.3)% and 23.8 (4.2)%,
respectively. Pearson product moment correlations for male and female body fat percentages between the three methods were
high, ranging from 0.81 to 0.86 (P < 0.05). However, compared to the criterion measure of body fat percentage (HYD), the magnitude of agreement BIA and SKF
revealed a different pattern. The mean absolute difference between HYD and BIA measurements of body fat for males was −0.8
(2.0)% fat, and between HYD and SKF was it was 0.2 (1.7)% fat. The mean absolute difference for females between HYD and BIA
was −1.2 (2.5)%; for HYD and SKF it was −1.4 (2.2)%. Compared to the HYD measures for males and females, the BIA and SKF measures
were as much as a 3.8% underestimation and a 6.2% overestimation of body fat. This study provides evidence that the strength
of a correlation does not indicate agreement between two methods. In future, reliability and validity studies should examine
the absolute differences between two variables and calculate limits of agreement around which a practitioner can appreciate
the precision of the methodologies.
Accepted: 26 August 1997 相似文献
57.
Shashikala R. Inamdar Sachin M. Eligar Suhas Ballal Shivakumar Belur Rajiv D. Kalraiya Bale M. Swamy 《Glycoconjugate journal》2016,33(1):19-28
Lectins are carbohydrate binding proteins that are gaining attention as important tools for the identification of specific glycan markers expressed during different stages of the cancer. We earlier reported the purification of a mitogenic lectin from human pathogenic fungus Cephalosporium curvulum (CSL) that has complex sugar specificity when analysed by hapten inhibition assay. In the present study, we report the fine sugar specificity of CSL as determined by glycan array analysis. The results revealed that CSL has exquisite specificity towards core fucosylated N-glycans. Fucosylated trimannosyl core is the basic structure required for the binding of CSL. The presence of fucose in the side chain further enhances the avidity of CSL towards such glycans. The affinity of CSL is drastically reduced towards the non-core fucosylated glycans, in spite of their side chain fucosylation. CSL showed no binding to the tested O-glycans and monosaccharides. These observations suggest the unique specificity of CSL towards core fucosylated N-glycans, which was further validated by binding of CSL to human colon cancer epithelial and hepatocarcinoma cell lines namely HT29 and HepG2, respectively, that are known to express core fucosylated N-glycans, using AOL and LCA as positive controls. LCA and AOL are fucose specific lectins that are currently being used clinically for the diagnosis of hepatocellular carcinomas. Most of the gastrointestinal markers express core fucosylated N-glycans. The high affinity and exclusive specificity of CSL towards α1-6 linkage of core fucosylated glycans compared to other fucose specific lectins, makes it a promising molecule that needs to be further explored for its application in the diagnosis of gastrointestinal cancer. 相似文献
58.
Alex G. Lee Megan Hagenauer Devin Absher Kathleen E. Morrison Tracy L. Bale Richard M. Myers Stanley J. Watson Huda Akil Alan F. Schatzberg David M. Lyons 《Biology of sex differences》2017,8(1):36
Background
Stress is a recognized risk factor for mood and anxiety disorders that occur more often in women than men. Prefrontal brain regions mediate stress coping, cognitive control, and emotion. Here, we investigate sex differences and stress effects on prefrontal cortical profiles of gene expression in squirrel monkey adults.Methods
Dorsolateral, ventrolateral, and ventromedial prefrontal cortical regions from 18 females and 12 males were collected after stress or no-stress treatment conditions. Gene expression profiles were acquired using HumanHT-12v4.0 Expression BeadChip arrays adapted for squirrel monkeys.Results
Extensive variation between prefrontal cortical regions was discerned in the expression of numerous autosomal and sex chromosome genes. Robust sex differences were also identified across prefrontal cortical regions in the expression of mostly autosomal genes. Genes with increased expression in females compared to males were overrepresented in mitogen-activated protein kinase and neurotrophin signaling pathways. Many fewer genes with increased expression in males compared to females were discerned, and no molecular pathways were identified. Effect sizes for sex differences were greater in stress compared to no-stress conditions for ventromedial and ventrolateral prefrontal cortical regions but not dorsolateral prefrontal cortex.Conclusions
Stress amplifies sex differences in gene expression profiles for prefrontal cortical regions involved in stress coping and emotion regulation. Results suggest molecular targets for new treatments of stress disorders in human mental health.59.
Nesidiocoris tenuis Reuter (Hemiptera: Miridae) is a polyphagous mirid currently used for the control of leafminers, thrips, whitefly and spider
mites in Mediterranean regions to which it is indigenous. This study investigates the establishment potential of N. tenuis in cool temperate climates typical of northern Europe through assessment of its thermal biology and low temperature tolerance
in laboratory and field experiments. The developmental threshold of N. tenuis was estimated to be 12.9°C with no indication of ability to diapause. Supercooling points of the acclimated and non-acclimated
adults and nymphs of the mirid were between −17.6° and −21.5°C and the LTemp50 was around −12°C, indicating a high level of pre-freeze mortality. The LTime50 at 5°C was nine days and 100% mortality occurred after less than four weeks of winter field exposure. Collectively these
data suggest that N. tenuis is unlikely to establish in northern Europe and would therefore have little or no non-target effects on native species in
such regions. 相似文献
60.
Michael CW Chan Renee WY Chan Wendy CL Yu Carol CC Ho WH Chui CK Lo Kit M Yuen Yi Guan John M Nicholls JS Malik Peiris 《Respiratory research》2009,10(1):102