全文获取类型
收费全文 | 153篇 |
免费 | 13篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 13篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 17篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 1篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1992年 | 1篇 |
1978年 | 2篇 |
1972年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有166条查询结果,搜索用时 31 毫秒
11.
Qamar R Ayub Q Mohyuddin A Helgason A Mazhar K Mansoor A Zerjal T Tyler-Smith C Mehdi SQ 《American journal of human genetics》2002,70(5):1107-1124
Eighteen binary polymorphisms and 16 multiallelic, short-tandem-repeat (STR) loci from the nonrecombining portion of the human Y chromosome were typed in 718 male subjects belonging to 12 ethnic groups of Pakistan. These identified 11 stable haplogroups and 503 combination binary marker/STR haplotypes. Haplogroup frequencies were generally similar to those in neighboring geographical areas, and the Pakistani populations speaking a language isolate (the Burushos), a Dravidian language (the Brahui), or a Sino-Tibetan language (the Balti) resembled the Indo-European-speaking majority. Nevertheless, median-joining networks of haplotypes revealed considerable substructuring of Y variation within Pakistan, with many populations showing distinct clusters of haplotypes. These patterns can be accounted for by a common pool of Y lineages, with substantial isolation between populations and drift in the smaller ones. Few comparative genetic or historical data are available for most populations, but the results can be compared with oral traditions about origins. The Y data support the well-established origin of the Parsis in Iran, the suggested descent of the Hazaras from Genghis Khan's army, and the origin of the Negroid Makrani in Africa, but do not support traditions of Tibetan, Syrian, Greek, or Jewish origins for other populations. 相似文献
12.
In this paper, we demonstrate that the sensitivity of triple-resonance NMR experiments can be enhanced significantly through quenching scalar coupling mediated relaxation by using composite-pulse decoupling (CPD) or an adiabatic decoupling sequence on aliphatic, in particular alpha-carbons in 13C/15N-labeled proteins. The CPD-HNCO experiment renders 50% sensitivity enhancement over the conventional CT-HNCO experiment performed on a 12 kDa FK506 binding protein, when a total of 266 ms of amide nitrogen–carbonyl carbon defocusing and refocusing periods is employed. This is a typical time period for the direct detection of hydrogen bonds in proteins via trans-hydrogen bond 3h
J
NC couplings. The experimental data fit theoretical analysis well. The significant enhancement in sensitivity makes the experiment more applicable to larger-sized proteins without resorting to perdeuteration. 相似文献
13.
Munir A. Anwar Mazhar Iqbal Muhammad A. Qamar Moazur Rehman Ahmad M. Khalid 《World journal of microbiology & biotechnology》2000,16(2):135-138
A sensitive and precise spectrophotometric method has been developed for the determination of copper(I) in bacterial leach liquors produced by the action of Thiobacillus ferrooxidans and T. thiooxidans on copper ores. In this method bicinchoninic acid (BCA) has been used as the chromogenic reagent which produces a stable purple complex with Cu(I) which was found to obey Beer's Law and with max at 560 nm. The coloured complex has a molar extinction coefficient () value of 6.6 × 103 l mol–1 cm–1; specific absorptivity () value of 0.104 ml–1 g cm–1 and the Sandell sensitivity (S) value was 0.0096 g cm2. Optimal conditions for development of coloration/sensitivity were determined. Interferences due to cations and anions were investigated and various masking agents for alleviating their inhibition were studied. The method has been found very useful in determining ratios of Cu(I) to Cu(II) in bacterial leach liquors and should play a significant role in determining the reaction mechanisms of biological leaching and for environmental monitoring. 相似文献
14.
Katherine E. Beaney Jackie A. Cooper Saleem Ullah Shahid Waqas Ahmed Raheel Qamar Fotios Drenos Martin A. Crockard Steve E. Humphries 《PloS one》2015,10(7)
BackgroundNumerous risk prediction algorithms based on conventional risk factors for Coronary Heart Disease (CHD) are available but provide only modest discrimination. The inclusion of genetic information may improve clinical utility.MethodsWe tested the use of two gene scores (GS) in the prospective second Northwick Park Heart Study (NPHSII) of 2775 healthy UK men (284 cases), and Pakistani case-control studies from Islamabad/Rawalpindi (321 cases/228 controls) and Lahore (414 cases/219 controls). The 19-SNP GS included SNPs in loci identified by GWAS and candidate gene studies, while the 13-SNP GS only included SNPs in loci identified by the CARDIoGRAMplusC4D consortium.ResultsIn NPHSII, the mean of both gene scores was higher in those who went on to develop CHD over 13.5 years of follow-up (19-SNP p=0.01, 13-SNP p=7x10-3). In combination with the Framingham algorithm the GSs appeared to show improvement in discrimination (increase in area under the ROC curve, 19-SNP p=0.48, 13-SNP p=0.82) and risk classification (net reclassification improvement (NRI), 19-SNP p=0.28, 13-SNP p=0.42) compared to the Framingham algorithm alone, but these were not statistically significant. When considering only individuals who moved up a risk category with inclusion of the GS, the improvement in risk classification was statistically significant (19-SNP p=0.01, 13-SNP p=0.04). In the Pakistani samples, risk allele frequencies were significantly lower compared to NPHSII for 13/19 SNPs. In the Islamabad study, the mean gene score was higher in cases than controls only for the 13-SNP GS (2.24 v 2.34, p=0.04). There was no association with CHD and either score in the Lahore study.ConclusionThe performance of both GSs showed potential clinical utility in European men but much less utility in subjects from Pakistan, suggesting that a different set of risk loci or SNPs may be required for risk prediction in the South Asian population. 相似文献
15.
The accurate modeling of various features in high energy astrophysical scenarios requires the solution of the Einstein equations together with those of special relativistic hydrodynamics (SRHD). Such models are more complicated than the non-relativistic ones due to the nonlinear relations between the conserved and state variables. A high-resolution shock-capturing central upwind scheme is implemented to solve the given set of equations. The proposed technique uses the precise information of local propagation speeds to avoid the excessive numerical diffusion. The second order accuracy of the scheme is obtained with the use of MUSCL-type initial reconstruction and Runge-Kutta time stepping method. After a discussion of the equations solved and of the techniques employed, a series of one and two-dimensional test problems are carried out. To validate the method and assess its accuracy, the staggered central and the kinetic flux-vector splitting schemes are also applied to the same model. The scheme is robust and efficient. Its results are comparable to those obtained from the sophisticated algorithms, even in the case of highly relativistic two-dimensional test problems. 相似文献
16.
Randeep Singh Qamar Qureshi Kalyanasundaram Sankar Paul R. Krausman Surendra Prakash Goyal Kerry L. Nicholson 《Acta theriologica》2014,59(4):521-527
We used camera trapping in conjunction with a spatial explicit capture–recapture model to estimate striped hyena (Hyaena hyaena) density and occupancy models to investigate factors affecting striped hyena detection probabilities in Ranthambhore Tiger Reserve (RTR), Rajasthan, India. A sampling effort of 4,450 trap days/nights over 75 days yield 68 photo captures of 21 unique striped hyenas (based on individual markings and visual identification); the estimated striped hyena density was 5.49?±?1.27 individuals/100 km2. Results of our occupancy model suggested that a rugged terrain is an important factor that influences striped hyena detection probability. Correlation with striped hyena detection with human settlement provides evidence of social tolerance of striped hyena towards humans, and more occurrence of resources allowed coexistence of hyena in a human-dominated landscape. This elasticity (inhabited areas close to humans) demonstrated by striped hyenas is an exception among carnivore communities living in this semi-arid habitat. 相似文献
17.
Muhammad Ajmal Waqas Ahmed Ahmed Sadeque Syeda Hafiza Benish Ali Syed Habib Bokhari Nuzhat Ahmed Raheel Qamar 《Molecular biology reports》2010,37(8):3869-3875
Familial Hypercholesterolemia (FH) results in elevated levels of blood lipids including total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) with normal triglycerides (TG). This disease is one of the major contributors towards an early onset of coronary heart disease (CHD). The aim of the present study was to identify the genes responsible for causing FH in Pakistani population, for this purpose a large consanguineous FH family was selected for genetic analysis. Serum lipid levels, including TC, TG, LDL-C and high density lipoprotein cholesterol (HDL-C), were determined in patients and healthy controls. In order to find the causative mutation in this family, direct sequencing of the low density lipoprotein receptor (LDLR) gene was performed. In addition the part of the Apolipoprotein-B (APOB) gene containing the mutations R3500Q and R3500W was also sequenced. Affected individuals of the family were found to have raised TC and LDL-C levels. Sequencing revealed an insertion mutation (c.2416_2417InsG) in exon 17 of the LDLR gene in all the affected individuals of the family. Common FH causing APOB mutations were not present in this family. Heterozygous individuals had TC levels ranging from ~300–500 mg/dl and the only homozygous individual with typical xanthomas had TC levels exceeding 900 mg/dl. This is the first report of a known LDLR gene mutation causing FH in the Pakistani population. Despite a large heterogeneity of LDLR mutations there are still some common mutations which are responsible for FH throughout the world. 相似文献
18.
Dikla Bandah-Rozenfeld Rob W.J. Collin Eyal Banin Karlien L.M. Coene Anna M. Siemiatkowska Lina Zelinger Dirk J. Lefeber Inbar Erdinest Francesca Simonelli Ellen A.W. Blokland Caroline C.W. Klaver Raheel Qamar Sandro Banfi Dror Sharon Anneke I. den Hollander 《American journal of human genetics》2010,87(2):199-208
Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal diseases caused by progressive degeneration of the photoreceptor cells. Using autozygosity mapping, we identified two families, each with three affected siblings sharing large overlapping homozygous regions that harbored the IMPG2 gene on chromosome 3. Sequence analysis of IMPG2 in the two index cases revealed homozygous mutations cosegregating with the disease in the respective families: three affected siblings of Iraqi Jewish ancestry displayed a nonsense mutation, and a Dutch family displayed a 1.8 kb genomic deletion that removes exon 9 and results in the absence of seven amino acids in a conserved SEA domain of the IMPG2 protein. Transient transfection of COS-1 cells showed that a construct expressing the wild-type SEA domain is properly targeted to the plasma membrane, whereas the mutant lacking the seven amino acids appears to be retained in the endoplasmic reticulum. Mutation analysis in ten additional index cases that were of Dutch, Israeli, Italian, and Pakistani origin and had homozygous regions encompassing IMPG2 revealed five additional mutations; four nonsense mutations and one missense mutation affecting a highly conserved phenylalanine residue. Most patients with IMPG2 mutations showed an early-onset form of RP with progressive visual-field loss and deterioration of visual acuity. The patient with the missense mutation, however, was diagnosed with maculopathy. The IMPG2 gene encodes the interphotoreceptor matrix proteoglycan IMPG2, which is a constituent of the interphotoreceptor matrix. Our data therefore show that mutations in a structural component of the interphotoreceptor matrix can cause arRP. 相似文献
19.
20.