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31.
Cloning and characterization of DXS6673E, a candidate gene for X-linked mental retardation in Xq13.1 总被引:3,自引:0,他引:3
van der Maarel SM; Scholten IH; Huber I; Philippe C; Suijkerbuijk RF; Gilgenkrantz S; Kere J; Cremers FP; Ropers HH 《Human molecular genetics》1996,5(7):887-897
In several families with non-specific X-linked mental retardation (XLMR)
linkage analyses have assigned the underlying gene defect to the
pericentromeric region of the X chromosome, but none of these genes have
been isolated so far. Here, we report on the cloning and characterization
of a novel gene, DXS6673E, that maps to Xq13.1, is subject to
X-inactivation and is disrupted in the 5' untranslated region by a balanced
X;13 translocation in a mentally retarded female. The DXS6673E gene is
highly conserved among vertebrates and its expression is most abundant in
brain. It encodes a hydrophilic protein of 1358 amino acids (aa) that does
not show sequence homology to other known proteins. A segment of this
protein consisting of neutral and hydrophobic aa with a proline residue in
every second position may represent a transmembrane domain. Almost complete
sequence identity was found between the 3' end of the DXS6673E gene and two
expressed sequence tags (ESTs) and between the 5' end of the DXS6673E gene
and a third EST. Moreover, weaker sequence similarity was observed between
coding regions and two other ESTs.
相似文献
32.
Autosomal recessive retinitis pigmentosa and cone-rod dystrophy caused by splice site mutations in the Stargardt's disease gene ABCR 总被引:12,自引:2,他引:12
Cremers FP; van de Pol DJ; van Driel M; den Hollander AI; van Haren FJ; Knoers NV; Tijmes N; Bergen AA; Rohrschneider K; Blankenagel A; Pinckers AJ; Deutman AF; Hoyng CB 《Human molecular genetics》1998,7(3):355-362
Ophthalmological and molecular genetic studies were performed in a
consanguineous family with individuals showing either retinitis pigmentosa
(RP) or cone-rod dystrophy (CRD). Assuming pseudodominant (recessive)
inheritance of allelic defects, linkage analysis positioned the causal gene
at 1p21-p13 (lod score 4.22), a genomic segment known to harbor the ABCR
gene involved in Stargardt's disease (STGD) and age- related macular
degeneration (AMD). We completed the exon-intron structure of the ABCR gene
and detected a severe homozygous 5[prime] splice site mutation,
IVS30+1G->T, in the four RP patients. The five CRD patients in this
family are compound heterozygotes for the IVS30+1G- >T mutation and a
5[prime] splice site mutation in intron 40 (IVS40+5G- >A). Both splice
site mutations were found heterozygously in two unrelated STGD patients,
but not in 100 control individuals. In these patients the second mutation
was either a missense mutation or unknown. Since thus far no STGD patients
have been reported to carry two ABCR null alleles and taking into account
that the RP phenotype is more severe than the STGD phenotype, we
hypothesize that the intron 30 splice site mutation represents a true null
allele. Since the intron 30 mutation is found heterozygously in the CRD
patients, the IVS40+5G->A mutation probably renders the exon 40 5[prime]
splice site partially functional. These results show that mutations in the
ABCR gene not only result in STGD and AMD, but can also cause autosomal
recessive RP and CRD. Since the heterozygote frequency for ABCR mutations
is estimated at 0.02, mutations in ABCR might be an important cause of
autosomal recessive and sporadic forms of RP and CRD.
相似文献
33.
A Pro51Ser mutation in the COCH gene is associated with late onset autosomal dominant progressive sensorineural hearing loss with vestibular defects 总被引:14,自引:0,他引:14
de Kok YJ; Bom SJ; Brunt TM; Kemperman MH; van Beusekom E; van der Velde- Visser SD; Robertson NG; Morton CC; Huygen PL; Verhagen WI; Brunner HG; Cremers CW; Cremers FP 《Human molecular genetics》1999,8(2):361-366
We analysed a Dutch family with autosomal dominant non-syndromic
progressive sensorineural hearing loss and mapped the underlying gene
defect by genetic linkage analysis to a 11.0 cM region overlapping the
DFNA9 interval on chromosome 14q12-q13. Clinically, the Dutch family
differs from the original DFNA9 family by a later age at onset and a more
clearly established vestibular impairment. A gene that is highly and
specifically expressed in the human fetal cochlea and vestibule, COCH
(previously described as Coch5B2 ), was mapped to the DFNA9 critical
region. Sequence analysis revealed a 208C-->T mutation in the COCH gene,
resulting in a Pro51Ser substitution in the predicted protein in all
affected individuals of the family but not in unaffected family members and
200 control individuals. The same mutation was also identified in three
apparently unrelated families with a similar phenotype, suggesting the
presence of a Dutch founder mutation. The function of COCH is unknown but
several characteristics of the protein point to a structural role in the
extracellular matrix. The mutant serine at position 51 is situated between
cysteines and possibly interferes with proper COCH protein folding or its
interaction with extracellular matrix proteins.
相似文献
34.
35.
Lisa FP Ng Martin L Hibberd Eng-Eong Ooi Kin-Fai Tang Soek-Ying Neo Jenny Tan Karuturi R Krishna Murthy Vinsensius B Vega Jer-Ming Chia Edison T Liu Ee-Chee Ren 《BMC infectious diseases》2004,4(1):1-11
Background
Schistosoma mansoni and Plasmodium falciparum are common infections of school aged children in Kenya. They both cause enlargement of the spleen, but their relative contribution to the condition of splenomegaly remains unknown in areas where both infections are endemic. Here, we have investigated whether relatively high exposure to both infections has a clinically measurable effect on this condition.Methods
96 children aged 6–16 years living along a ten kilometre stretch and within 4 km south of a river that is a source of both S. mansoni and malaria infections were examined clinically for splenomegaly along the mid clavicular line (MCL) and mid axillary line (MAL). The survey was conducted outside the malaria transmission season. The consistency of the organ was recorded as soft, firm or hard. Mapping of the locations of houses and the course of the river was undertaken. Egg counts were mapped at the household level, as were IgG3 responses to Plasmodium falciparum schizont antigen (anti-Pfs IgG3), in order to identify areas with relatively high exposure to both infections, either infection or neither infection. ANOVA was used to test for differences in egg counts, IgG3 levels and the magnitude of spleen enlargement between these areas.Results
4 contiguous sectors were identified, one where anti-Pfs IgG3 responses and S. mansoni egg counts were both high, one where only anti-Pfs IgG3 responses were high, one where only egg counts were high, and one where both anti-Pfs IgG3 responses and egg counts were low. Spleen MAL and MCL values were significantly higher amongst children from the sector with highest IgG3 levels and highest egg counts but similar amongst children from elsewhere. Both egg counts and anti-Pfs IgG3 responses were significantly higher in children with MAL values >=4 cm. Hardening of spleens was associated with proximity of domicile to the river.Conclusions
Micro-geographical variation in exposure to S. mansoni and malaria infections can be exploited to investigate the chronic impact of these two infections. These results provide firm evidence that relatively high exposure to both infections exacerbates splenomegaly even outside the malaria transmission season. Major implications include assessing the burden of infection in school age-children. 相似文献36.
37.
38.
Solitary pulmonary nodules: CT assessment 总被引:29,自引:0,他引:29
Siegelman SS; Khouri NF; Leo FP; Fishman EK; Braverman RM; Zerhouni EA 《Radiology》1986,160(2):307-312
Computed tomography (CT) was used to examine 634 solitary pulmonary nodules (SPNs). Each lesion was assessed as benign or indeterminate on the basis of CT criteria. Benign nodules made up 44% of all SPNs and 58% of the 431 that were 2 cm or less in diameter. All malignant SPNs were assessed as indeterminate, and adenocarcinoma (42%) was the most common primary malignancy. A total of 176 (63% of benign SPNs) were correctly assessed as benign by CT. Ninety SPNs assessed as diffusely calcified were not so identified by conventional tomography at outside institutions. An SPN can be reliably assessed by CT as benign if it exhibits high attenuation values, exceeding a critical level and distributed diffusely throughout a CT section through the center of the lesion and a well-defined edge. Although 38 of 283 (13.4%) primary lung cancers contained localized calcification, there was no significant overlap with the diffuse calcification of benign lesions. Central carcinoid tumors may contain focal ossification, but such lesions may be recognized by noting the proximity of larger bronchi. Assessment of SPNs by CT is most effective for lesions 2.0 cm or less in diameter. For larger lesions, the frequency of benign disease was decreased (14.3% of 203), as was the percentage of benign SPNs correctly assessed as benign by CT (37.9%). 相似文献
39.
Mutational scanning of large genes by extensive PCR multiplexing and two-dimensional electrophoresis: application to the RB1 gene 总被引:2,自引:0,他引:2
Van Orsouw NJ; Li D; van der Vlies P; Scheffer H; Eng C; Buys CH; Li FP; Vijg J 《Human molecular genetics》1996,5(6):755-761
With the rapid increase in the number of identified human disease genes,
the development of accurate and cost-efficient mutation tests has become
opportune. Here we present a combination of extensive PCR multiplexing and
two-dimensional (2-D) DNA electrophoresis to screen for mutations in 26
exons of the retinoblastoma (RB1) tumor suppressor gene. In 2-D
electrophoresis, fragments are separated according to size and base pair
sequence in non-denaturing and denaturing gradient gels, respectively. All
target fragments, designed to have optimal melting characteristics, were
prepared in a two-step PCR (a 6-plex long-PCR pre- amplification and a
subsequent 25-plex short-PCR) followed by heteroduplexing. The mixture of
PCR amplicons was then subjected to 2-D electrophoresis under a single set
of experimental conditions. With this design, 35 previously identified
mutations in 18 different exons were detected in 33 bilateral
retinoblastoma patients. These results suggest that 2-D electrophoresis in
this format provides a generally applicable, practical and fast way to
diagnose with high accuracy large genes for a broad spectrum of possible
disease-causing mutations.
相似文献
40.
Ultrasonographic B-mode images were obtained at various exposure levels with three real-time diagnostic scanners. Adult human and tissue-equivalent phantom images were compared in terms of diagnostic content and depth of penetration. For the exposure level settings used, spatial-peak pulse-average intensities ranged from approximately 10 to 500 W/cm2. At the 3.50-3.75-MHz nominal frequencies used in the study, images of the human abdomen showed little discernible change in quality with varying exposure levels. However, phantom tests confirmed that depth of penetration is a function of exposure level. The results suggest that a judicious use of exposure level and receiver gain controls can be a practical means for minimizing patient exposure to ultrasound without sacrifice of diagnostic effectiveness. 相似文献