全文获取类型
收费全文 | 148篇 |
免费 | 10篇 |
出版年
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 12篇 |
2014年 | 9篇 |
2013年 | 14篇 |
2012年 | 13篇 |
2011年 | 4篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 8篇 |
2006年 | 6篇 |
2005年 | 3篇 |
2004年 | 6篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 6篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 4篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1970年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有158条查询结果,搜索用时 375 毫秒
11.
12.
13.
KNaSO4 microphosphor doped with Ce,Gd and Ce,Tb and prepared by a wet chemical method was studied using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) characterization. KNaSO4 has a 5‐µm particle size detected by SEM. KNaSO4:Ce3+,Tb3+ showed blue and green emission (at 494 nm, 557 nm, 590 nm) of Tb3+ due to 5D4 → 7FJ (J = 4, 5, 6) transitions. KNaSO4:Ce3+,Gd3+ showed luminescence in the ultraviolet (UV) light region at 314 nm for an excitation at 271 nm wavelength. It was observed that efficient energy transfer took place from Ce3+ → Gd3+ and Ce3+ → Tb3+ sublattices indicating that Ce3+ could effectively sensitize Gd3+ or Tb3+ (green emission). Ce3+ emission weakened and Gd3+ or Tb3+ enhanced the emission significantly in KNaSO4. This paper discusses the development and understanding of photoluminescence and the effect of Tb3+ and Gd3+ on KNaSO4:Ce3+. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
14.
Multicenter evaluation of reverse line blot assay for detection of drug resistance in Mycobacterium tuberculosis clinical isolates 总被引:7,自引:0,他引:7
Mokrousov I Bhanu NV Suffys PN Kadival GV Yap SF Cho SN Jordaan AM Narvskaya O Singh UB Gomes HM Lee H Kulkarni SP Lim KC Khan BK van Soolingen D Victor TC Schouls LM 《Journal of microbiological methods》2004,57(3):323-335
A multicenter study was conducted with the objective to evaluate a reverse line blot (RLB) assay to detect resistance to rifampin (RIF), isoniazid (INH), streptomycin (STR), and ethambutol (EMB) in clinical isolates of Mycobacterium tuberculosis. Oligonucleotides specific for wild type and mutant (drug resistance linked) alleles of the selected codons in the genes rpoB, inhA, ahpC, rpsL, rrs, embB, were immobilized on a nylon membrane. The RLB assay conditions were optimized following analysis of DNA samples with known sequences of the targeted genes. For validation of the method at different geographical locations, the membranes were sent to seven laboratories in six countries representing the regions with high burdens of multudrug-resistant tuberculosis. The reproducibility of the assay for detection of rpoB genotypes was initially evaluated on a blinded set of twenty reference DNA samples with known allele types and overall concordant results were obtained. Further mutation analysis was performed by each laboratory on the local strains. Upon RLB analysis of 315 clinical isolates from different countries, 132 (85.2%) of 155 RIF-resistant and 28 (51.0%) of 55 EMB-resistant isolates were correctly identified, showing applicability of the assay when targeting the rpoB hot-spot region and embB306. Mutations in the inhA and ahpC promoter regions, conferring resistance to INH, were successfully identified in respectively 16.9% and 13.2% of INH-resistant strains. Likewise, mutations in rrs513 and rpsL88 that confer resistance to STR were identified in respectively 15.1% and 10.7% of STR-resistant strains. It should be mentioned that mutation analysis of the above targets usually requires rather costly DNA sequencing to which the proposed RLB assay presents rapid and inexpensive alternative. Furthermore, the proposed method requires the same simple equipment as that used for spoligotyping and permits simultaneous analysis of up to 40 samples. This technique is a first attempt to combine different targets in a single assay for prediction of antituberculosis drugs resistance. It is open to further development as it allows easy incorporation of new probes for detection of mutations in other genes associated with resistance to second-line (e.g., fluoroquinolones) and new antituberculosis compounds. 相似文献
15.
Although the importance of radiation-induced adaptive response has been recognized in human health, risk assessment and clinical
application, the phenomenon has not been understood well in terms of survival of animals. To examine this aspect Swiss albino
mice were irradiated with different doses (2–10 Gy) at 0015 Gy/s dose rate and observed on a regular basis for 30 days. Since
almost 50% lethality was seen with 8 Gy, it was selected as the challenging dose for further studies. Irradiation of mice
with conditioning doses (0.25 or 0.5 Gy) and subsequent exposure to 8 Gy caused significant increase in the survival of mice
compared to irradiated control. The splitting of challenging dose did not influence the efficiency of conditioning doses (0.25
Gy and 0.5 Gy) to induce an adaptive response. However conditioning doses given in fractions (0.25 Gy + 0.25 Gy) or (0.5 Gy
+ 0.5 Gy) were able to modulate the response of challenging dose of 8 Gy. These results clearly showed the occurrence of adaptive
response in terms of survival of animals. The conditioning dose given in small fractions seemed to be more effective. The
findings have been discussed from a mechanistic point of view. The possible biological implications, potential medical benefits,
uncertainties and controversies related to adaptive response have also been addressed 相似文献
16.
A duplication growth model of gene expression networks 总被引:8,自引:0,他引:8
17.
18.
19.
Chromosome translocations have been known to affect disjunction of chromosomes unrelated to the translocation in the mouse and in Drosophila. However, in humans, an interchromosomal effect in chromosome translocations has not been demonstrated. The availability of techniques that allow the study of nondisjunction in sperm cells has permitted us to evaluate the possibility of an interchromosomal effect in male translocation heterozygotes. In this study, multicolor fluorescence in situ hybridization was used to determine levels of disomy for the clinically relevant chromosomes X, Y, 13, 18, and 21 in 332,858 spermatozoa from nine reciprocal translocation heterozygotes and nine controls with normal karyotypes. The specific translocations studied were as follows: t(10;12)(p26.1;p13.3), t(2;18)(p21;q11.2), t(3;19)(p25;q12), t(5;8)(q33;q13), t(11;22)(q23;q11), t(3;4)(p25;p16), t(8;9) (q24.2;q32), t(10;18)(q24.1;p11.2), and t(4;10)(q33;p12.2). Comparisons of disomy rates between carriers and controls were performed by using the Mann-Whitney test. Our results showed that the rates of sex chromosome hyperhaploidy were similar in controls (0.21%) and in translocation carriers (0.19%). Similarly, the frequencies of disomy for chromosomes 13, 18, and 21 did not differ significantly between controls and carriers (0.05% versus 0.08%, 0.07% versus 0.03%, and 0.14% versus 0.20%, respectively). Sex chromosome nondisjunction was more common than nondisjunction of chromosomes 13 and 18 both in controls (P=0.0057) and in carriers (P=0.0008). Similarly, the rates of chromosome disomy for chromosome 21 were higher than those for chromosomes 13 and 18 in both controls (P=0.0031) and translocation carriers (P=0.0057). In our study, the excess of chromosome 21 disomy versus disomy of the other autosomes was more pronounced in carriers than in controls. Thus, although the difference of disomy 21 between controls and carriers was not statistically significant, it is worthy of attention. 相似文献
20.
Four flavonol glucosides, one new, have been isolated from a methanolic extract of Phlomis spectabilis. Their structures were established as the 3-glucosides and 3-(6″-(E)-p-coumaroyl)glucosides of kaempferol and of kaempferol 7,4′-dimethyl ether. 相似文献