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71.
Enhanced electrochemical resolution of anodic processes is possible in the presence of [N(nBu)4][B(C6F5)4], 1, as supporting electrolyte over that obtained in the presence of [N(nBu)4][PF6]. By changing the anion of the supporting electrolyte to a salt having [B(C6F5)4]−, anions, electrochemical processes of especially cationic analytes can benefit. Thus, the redox chemistry of 0.5 mmol dm−3 solutions of [Ru2(μ-FcCOO)4·(CH3CH2OH)2][PF6], 2, Fc = ferrocenyl, in CH2Cl2/[N(nBu)4][B(C6F5)4] were found to involve four well-resolved ferrocenyl-based electrochemical reversible redox processes as well as reduction of RuIII-RuII. At 1.0 mmol dm−3 concentrations of 2, or in the presence of [N(nBu)4][PF6], the four ferrocenyl processes coalesced into only two waves as a result of (Fc+)?() ion paring. Seventeen of the possible 18 one-electron transfer processes of the biscadmium trisphthalocyaninato complex [Cd2{Pc(C6H13)8}3], 3, could be observed in THF/[N(nBu)4][B(C6F5)4], but the electrochemical window of CH2Cl2/[N(nBu)4][B(C6F5)4] only allowed detection of 15 of these processes. Although reduction processes were unaffected, THF solvation leading to species such as (3n+)(THF)x with 1 ? n ? 4 and x ? 1 as well as ion pair formation of the type (3n+)?() prevented good resolution of oxidation processes. The CH2Cl2/[N(nBu)4][B(C6F5)4] system also allowed detection of reversible one-electron transfer ferrocenyl (Fc/Fc+) and ruthenocenyl-based (Rc/Rc+) processes for both enol and keto isomers of the β-diketone FcCOCH2CORc, 4, Rc = ruthenocenyl. In CH3CN/[N(nBu)4][PF6], the ruthenocenyl moiety was oxidised to a RuIV species. 相似文献
72.
Characterization of cry1, cry2, and cry9 genes in Bacillus thuringiensis isolates from China 总被引:5,自引:0,他引:5
Bacillus thuringiensis isolates from different ecological regions and sources of China were analyzed to study the distribution and diversity of cry genes and to detect the presence of novel cry genes. Strains containing cry1-type genes were the most abundant and represent 237 of the 310 B. thuringiensis isolates (76.5%). About 70 and 15.5% of the isolates contained a cry2 gene or cry9 gene, respectively, while 10.0% of the strains did not contain a cry1, cry2, or cry9 gene. Among the cry1 containing isolates, cry1A (67.7%), cry1I (60.6%), cry1C (43.9%), and cry1D (39.4%) genes were the most abundant. Forty-three different cry1 gene profiles were detected in this collection. Several cry1 genes were associated at a high frequency, such as the cry1C-cry1D and cry1A-cry1I gene combination. The cry1A and cry2 amplicons were digested with selected restriction enzymes to examine sequence diversity. Based on this RFLP analysis, one novel cry1A-type gene was observed. 相似文献
73.
Alexander TW Sharma R Deng MY Whetsell AJ Jennings JC Wang Y Okine E Damgaard D McAllister TA 《Journal of biotechnology》2004,112(3):255-266
The stability of transgenic DNA encoding the synthetic cp4 epsps protein in a diet containing Roundup Ready (RR) canola meal was determined in duodenal fluid (DF) batch cultures from sheep. A real-time TaqMan PCR assay was designed to quantify the degradation of cp4 epsps DNA during incubation in DF at pH 5 or 7. The copy number of cp4 epsps DNA in the diet declined more rapidly (P < 0.05) in DF at pH 5 as compared to pH 7. The decrease was attributed mainly to microbial activity at pH 7 and perhaps to plant endogenous enzymes at pH 5. The 62-bp fragment of cp4 epsps DNA detected by real-time PCR reached a maximum of approximately 1600 copies in the aqueous phase of DF at pH 7, whereas less than 20 copies were detected during incubations in DF at pH 5. A 1363-bp sequence of cp4 epsps DNA was never detected in the aqueous fraction of DF. Additionally, genomic DNA isolated from RR canola seed was used to test the persistence of fragments of free DNA in DF at pH 3.2, 5, and 7, as well as in ruminal fluid and feces. Primers spanning the cp4 epsps DNA coding region amplified sequences ranging in size from 300 to 1363 bp. Free transgenic DNA was least stable in DF at pH 7 where fragments less than 527 bp were detected for up to 2 min and fragments as large as 1363 bp were detected for 0.5 min. This study shows that digestion of plant material and release of transgenic DNA can occur in the ovine small intestine. However, free DNA is rapidly degraded at neutral pH in DF, thus reducing the likelihood that intact transgenic DNA would be available for absorption through the Peyer's Patches in the distal ileum. 相似文献
74.
Bart Malfait Bart Dingenen Annemie Smeets Filip Staes Todd Pataky Mark A. Robinson Jos Vanrenterghem Sabine Verschueren 《PloS one》2016,11(4)
PurposeThe purpose was to assess if variation in sagittal plane landing kinematics is associated with variation in neuromuscular activation patterns of the quadriceps-hamstrings muscle groups during drop vertical jumps (DVJ).MethodsFifty female athletes performed three DVJ. The relationship between peak knee and hip flexion angles and the amplitude of four EMG vectors was investigated with trajectory-level canonical correlation analyses over the entire time period of the landing phase. EMG vectors consisted of the {vastus medialis(VM),vastus lateralis(VL)}, {vastus medialis(VM),hamstring medialis(HM)}, {hamstring medialis(HM),hamstring lateralis(HL)} and the {vastus lateralis(VL),hamstring lateralis(HL)}. To estimate the contribution of each individual muscle, linear regressions were also conducted using one-dimensional statistical parametric mapping.ResultsThe peak knee flexion angle was significantly positively associated with the amplitudes of the {VM,HM} and {HM,HL} during the preparatory and initial contact phase and with the {VL,HL} vector during the peak loading phase (p<0.05). Small peak knee flexion angles were significantly associated with higher HM amplitudes during the preparatory and initial contact phase (p<0.001). The amplitudes of the {VM,VL} and {VL,HL} were significantly positively associated with the peak hip flexion angle during the peak loading phase (p<0.05). Small peak hip flexion angles were significantly associated with higher VL amplitudes during the peak loading phase (p = 0.001). Higher external knee abduction and flexion moments were found in participants landing with less flexed knee and hip joints (p<0.001).ConclusionThis study demonstrated clear associations between neuromuscular activation patterns and landing kinematics in the sagittal plane during specific parts of the landing. These findings have indicated that an erect landing pattern, characterized by less hip and knee flexion, was significantly associated with an increased medial and posterior neuromuscular activation (dominant hamstrings medialis activity) during the preparatory and initial contact phase and an increased lateral neuromuscular activation (dominant vastus lateralis activity) during the peak loading phase. 相似文献
75.
Jesse H. Erasmus James Needham Syamal Raychaudhuri Michael S. Diamond David W. C. Beasley Stan Morkowski Henrik Salje Ildefonso Fernandez Salas Dal Young Kim Ilya Frolov Farooq Nasar Scott C. Weaver 《PLoS neglected tropical diseases》2015,9(10)
In December of 2013, chikungunya virus (CHIKV), an alphavirus in the family Togaviridae, was introduced to the island of Saint Martin in the Caribbean, resulting in the first autochthonous cases reported in the Americas. As of January 2015, local and imported CHIKV has been reported in 50 American countries with over 1.1 million suspected cases. CHIKV causes a severe arthralgic disease for which there are no approved vaccines or therapeutics. Furthermore, the lack of a commercially available, sensitive, and affordable diagnostic assay limits surveillance and control efforts. To address this issue, we utilized an insect-specific alphavirus, Eilat virus (EILV), to develop a diagnostic antigen that does not require biosafety containment facilities to produce. We demonstrated that EILV/CHIKV replicates to high titers in insect cells and can be applied directly in enzyme-linked immunosorbent assays without inactivation, resulting in highly sensitive detection of recent and past CHIKV infection, and outperforming traditional antigen preparations. 相似文献
76.
Sunny Eloot Daniel Schneditz Tom Cornelis Wim Van Biesen Griet Glorieux Annemie Dhondt Jeroen Kooman Raymond Vanholder 《PloS one》2016,11(1)
Aim
We studied various hemodialysis strategies for the removal of protein-bound solutes, which are associated with cardiovascular damage.Methods
This study included 10 patients on standard (3x4h/week) high-flux hemodialysis. Blood was collected at the dialyzer inlet and outlet at several time points during a midweek session. Total and free concentration of several protein-bound solutes was determined as well as urea concentration. Per solute, a two-compartment kinetic model was fitted to the measured concentrations, estimating plasmatic volume (V1), total distribution volume (Vtot) and intercompartment clearance (K21). This calibrated model was then used to calculate which hemodialysis strategy offers optimal removal. Our own in vivo data, with the strategy variables entered into the mathematical simulations, was then validated against independent data from two other clinical studies.Results
Dialyzer clearance K, V1 and Vtot correlated inversely with percentage of protein binding. All Ks were different from each other. Of all protein-bound solutes, K21was 2.7–5.3 times lower than that of urea. Longer and/or more frequent dialysis that processed the same amount of blood per week as standard 3x4h dialysis at 300mL/min blood flow showed no difference in removal of strongly bound solutes. However, longer and/or more frequent dialysis strategies that processed more blood per week than standard dialysis were markedly more adequate. These conclusions were successfully validated.Conclusion
When blood and dialysate flow per unit of time and type of hemodialyzer are kept the same, increasing the amount of processed blood per week by increasing frequency and/or duration of the sessions distinctly increases removal. 相似文献77.
Shaheed V. Omar Andreas Roth Nazir A. Ismail Linda Erasmus Marthie Ehlers Marleen Kock Nuraan Paulse Halima M. Said Anwar A. Hoosen Udo Reischl 《PloS one》2011,6(9)
Background
The LightCycler® Mycobacterium Detection Kit based on real-time PCR technology for the detection of Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium kansasii was recently developed. This study evaluated its analytical sensitivity, specificity and reproducibility.Methodology/Principal Findings
Plasmid standards were prepared and used to determine the limit of detection. The assay was also performed against organisms other than mycobacteria, other mycobacterial strains and interfering substances to exclude cross-reactivity and interference. Reference standards were prepared and tested to assess the assay''s reproducibility. All PCR assays were performed using the LightCycler® 2.0 Instrument. The detection limit for M. tuberculosis was 28 copies per microlitre. Neither cross-reactivity nor interference occurred with non-mycobacterial organisms and substances tested. Overall reproducibility for consecutive measurements, run-to-run, lot-to-lot, day-to-day and laboratory-to-laboratory achieved a coefficient of variance of less than two percent.Significance
The LightCycler® Mycobacterium Detection kit has shown to be a robust and accurate assay with the potential to be used as a rapid TB diagnostic test. 相似文献78.
Halima M. Said Nicole Kushner Shaheed V. Omar Andries W. Dreyer Hendrik Koornhof Linda Erasmus Yasmin Gardee Ivy Rukasha Elena Shashkina Natalie Beylis Gilla Kaplan Dorothy Fallows Nazir A. Ismail 《PloS one》2016,11(1)
Background
In South Africa and other high prevalence countries, transmission is a significant contributor to rising rates of multidrug resistant tuberculosis (MDR-TB). Thus, there is a need to develop an early detection system for transmission clusters suitable for high burden settings. We have evaluated the discriminatory power and clustering concordance of a novel and simple genotyping approach, combining spoligotyping with pncA sequencing (SpoNC), against two well-established methods: IS6110-RFLP and 24-loci MIRU-VNTR.Methods
A total of 216 MDR-TB isolates collected from January to June 2010 from the NHLS Central TB referral laboratory in Braamfontein, Johannesburg, representing a diversity of strains from South Africa, were included. The isolates were submitted for genotyping, pncA sequencing and analysis to the Centre for Tuberculosis in South Africa and the Public Health Research Institute Tuberculosis Center at Rutgers University in the United States. Clustering rates, Hunter-Gaston Discriminatory Indexes (HGI) and Wallace coefficients were compared between the methods.Results
Overall clustering rates were high by both IS6110-RFLP (52.8%) and MIRU-VNTR (45.8%), indicative of on-going transmission. Both 24-loci MIRU-VNTR and IS6110-RFLP had similar HGI (0.972 and 0.973, respectively), with close numbers of unique profiles (87 vs. 70), clustered isolates (129 vs. 146), and cluster sizes (2 to 26 vs. 2 to 25 isolates). Spoligotyping alone was the least discriminatory (80.1% clustering, HGI 0.903), with 28 unique types. However, the discriminatory power of spoligotyping was improved when combined with pncA sequencing using the SpoNC approach (61.8% clustering, HGI 0.958). A high proportion of MDR-TB isolates had mutations in pncA (68%, n = 145), and pncA mutations were significantly associated with clustering (p = 0.007 and p = 0.0013 by 24-loci MIRU-VNTR and IS6110-RFLP, respectively), suggesting high rates of resistance to pyrazinamide among all MDR-TB cases and particularly among clustered cases.Conclusion
We conclude that SpoNC provides good discrimination for MDR-TB surveillance and early identification of outbreaks in South Africa, with 24-loci MIRU-VNTR applied for pncA wild-type strains as needed. 相似文献79.
80.
Vanbroekhoven K Ryngaert A Bastiaens L Wattiau P Vancanneyt M Swings J De Mot R Springael D 《Environmental microbiology》2004,6(11):1123-1136
Sphingomonas is an organism of major interest for the degradation of organic contaminants in soils and other environments. A medium based on the aminoglycoside antibiotic streptomycin (Sm) was developed, which, together with the yellow pigmentation of Sphingomonas, facilitated the detection, recovery and quantification of culturable Sphingomonas from soils. All 29 previously described bacterial strains belonging to 17 different Sphingomonas species were able to grow on mineral media containing 200 microg ml(-1) streptomycin, showing that the capacity to resist high concentrations of Sm is a common characteristic within Sphingomonas. Incorporation of Sm into the mineral medium led to a significant reduction in the background microbial population and a concomitant 100 times more sensitive detection of Sphingomonas inoculated in non-sterile soil matrices. The Sm-containing medium was used to examine a variety of hydrocarbon-contaminated soils for the presence and biodiversity of Sphingomonas. Incorporation of Sm in the medium led to a significant increase in the number of yellow-pigmented colonies. Comparison of contaminated and non-contaminated soils derived from the same site revealed colonization by culturable yellow-pigmented Sm-resistant bacteria of the polluted location solely. Both yellow and non-yellow-pigmented colonies were purified from plates containing glucose and Sm, and BOX-polymerase chain reaction (PCR) was used to sort out clonally related strains. Representative strains from the major BOX-PCR clusters were identified using FAME and partial 16S rRNA gene sequencing. Forty-eight of 58 Sm-resistant isolates were identified as Sphingomonas sp. Streptomycin-resistant Sphingomonas isolates generated BOX-PCR diversity patterns that were site dependent and represented different species mainly belonging to Sphingomonas subgroups containing species formerly designated as Sphingopyxis and Sphingobium. The ability to degrade phenanthrene was only found in a minority of the Sphingomonas isolates, which all originated from soils containing high phenanthrene concentrations. 相似文献