全文获取类型
收费全文 | 6462篇 |
免费 | 453篇 |
国内免费 | 132篇 |
专业分类
耳鼻咽喉 | 3290篇 |
儿科学 | 191篇 |
妇产科学 | 41篇 |
基础医学 | 664篇 |
口腔科学 | 48篇 |
临床医学 | 431篇 |
内科学 | 254篇 |
皮肤病学 | 25篇 |
神经病学 | 445篇 |
特种医学 | 98篇 |
外科学 | 143篇 |
综合类 | 444篇 |
现状与发展 | 4篇 |
预防医学 | 592篇 |
眼科学 | 116篇 |
药学 | 143篇 |
3篇 | |
中国医学 | 36篇 |
肿瘤学 | 79篇 |
出版年
2024年 | 10篇 |
2023年 | 93篇 |
2022年 | 146篇 |
2021年 | 264篇 |
2020年 | 273篇 |
2019年 | 279篇 |
2018年 | 266篇 |
2017年 | 338篇 |
2016年 | 302篇 |
2015年 | 327篇 |
2014年 | 332篇 |
2013年 | 839篇 |
2012年 | 407篇 |
2011年 | 312篇 |
2010年 | 283篇 |
2009年 | 310篇 |
2008年 | 284篇 |
2007年 | 265篇 |
2006年 | 219篇 |
2005年 | 163篇 |
2004年 | 163篇 |
2003年 | 134篇 |
2002年 | 98篇 |
2001年 | 105篇 |
2000年 | 107篇 |
1999年 | 82篇 |
1998年 | 66篇 |
1997年 | 63篇 |
1996年 | 54篇 |
1995年 | 45篇 |
1994年 | 22篇 |
1993年 | 29篇 |
1992年 | 31篇 |
1991年 | 32篇 |
1990年 | 27篇 |
1989年 | 18篇 |
1988年 | 32篇 |
1987年 | 15篇 |
1986年 | 21篇 |
1985年 | 39篇 |
1984年 | 23篇 |
1983年 | 21篇 |
1982年 | 25篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 17篇 |
1975年 | 5篇 |
排序方式: 共有7047条查询结果,搜索用时 31 毫秒
21.
沈慧凤 《中国新药与临床杂志》1994,(6)
药用新辅料是药物制剂的基础材料和重要组成部分,在制剂剂型的发展和生产中起着关键作用。它不仅赋予药物一定的剂型,并且与提高药物的疗效、降低毒副作用有很大的关系。因此,研究开发、合理应用新辅料不仅是提高我国药物制剂质量和生产技术水平的重要方向,而且可取得较大的社会及经济效益。 相似文献
22.
Dawn Stacey RN MScN CON Annette M. O'Connor RN PhD † Cathy DeGrasse RN MScN ‡ Shailendra Verma MD FRCP § 《Health expectations》2003,6(1):3-18
Objective To develop and evaluate the effectiveness of a breast cancer prevention decision aid for women aged 50 and older at higher risk of breast cancer. Design Pre‐test–post‐test study using decision aid alone and in combination with counselling. Setting Breast Cancer Risk Assessment Clinic. Participants Twenty‐seven women aged 50–69 with 1.66% or higher 5‐year risk of breast cancer. Intervention Self‐administered breast cancer prevention decision aid. Main outcome measures Acceptability; decisional conflict; knowledge; realistic expectations; choice predisposition; intention to improve life‐style practices; psychological distress; and satisfaction with preparation for consultation. Results The decision aid alone, or in combination with counselling, decreased some dimensions of decisional conflict, increased knowledge (P < 0.01), and created more realistic expectations (P < 0.01). The aid in combination with counselling, significantly reduced decisional conflict (P < 0.01) and psychological distress (P < 0.02), helped the uncertain become certain (P < 0.02), and increased intentions to adopt healthier life‐style practices (P < 0.03). Women rated the aid as acceptable, and both women and practitioners were satisfied with the effect it had on the counselling session. Conclusion The decision aid shows promise as a useful decision support tool. Further research should compare the effect of the decision aid in combination with counselling to counselling alone. 相似文献
23.
Dr Ö. Özdamar C. N. Lopez D. K. Oller R. E. Eilers E. Miskiel Dr M. P. Lynch 《Medical & biological engineering & computing》1992,30(2):213-218
A microprocessor-based real-time digital vibrotactile vocoder system has been developed to train the deaf and for artificial
hearing research. The system is composed of a microcomputer module with a digital signal processor interface units and an
attenuator/driver circuit. Live or digitised (stored or synthetic) speech is presented to the skin spectrally through a belt
housing eight or 16 vibrators. Speech is processed in real time using a fast Fourier transform. The system is also capable
of presenting any arbitrary spatiotemporal pattern on the skin for artificial hearing experiments. A preliminary experiment
with a deaf subject indicates that the system is potentially an effective device for artificial hearing. 相似文献
24.
25.
The aims of this study were (1) to elicit the users' responses to four electronic head-mounted devices (Jordy, Flipperport, Maxport and NuVision) and (2) to correlate users' opinion with performance. Ten patients with early onset macular disease (EOMD) and 10 with age-related macular disease (AMD) used these electronic vision enhancement systems (EVESs) for a variety of visual tasks. A questionnaire designed in-house and a modified VF-14 were used to evaluate the responses. Following initial experience of the devices in the laboratory, every patient took home two of the four devices for 1 week each. Responses were re-evaluated after this period of home loan. No single EVES stood out as the strong preference for all aspects evaluated. In the laboratory-based appraisal, Flipperport typically received the best overall ratings and highest score for image quality and ability to magnify, but after home loan there was no significant difference between devices. Comfort of device, although important, was not predictive of rating once magnification had been taken into account. For actual performance, a threshold effect was seen whereby ratings increased as reading speed improved up to 60 words per minute. Newly diagnosed patients responded most positively to EVESs, but otherwise users' opinion could not be predicted by age, gender, diagnosis or previous CCTV experience. User feedback is essential in our quest to understand the benefits and shortcoming of EVESs. Such information should help guide both prescribing and future development of low vision devices. 相似文献
26.
Objective:To study whether adenovirus-mediated human β-nerve growth factor (Ad-hNGFβ) gene has any protective effect on blast hearing impairment. Methods:Deafness was induced by blast exposure (172.0 dB) in 30 healthy guinea pigs. On day 7 of blast exposure, Ad-hNGFβ was infused into the perilymphatic space of 20 animals as the study group (hNGFβ group), and artificial perilymph fluid (APF) was infused into the perilymphatic space of the other 10 animals as the control group. At weeks 1, 4 and 8 after blast exposure, the animals were sacrificed and the cochleae were removed for immunohistochemical and HE stainings. Results: Expression of Ad-hNGFβ protein was detected in each turn of the cochlea at the 1st week, with almost equal intensity in all turns. At the 4th week, the reactive intensity of the expression of Ad-hNGFβ protein decreased. At the 8th week, no expression was detectable. The results of HE staining showed that the amount of spiral ganglions in hNGFβ group was significantly greater than that of the control group at week 4 (P〈0.01). Conclusion: Ad-hNGFβ can be expressed at a high level and for a relatively long period in the blast impaired cochlea, suggesting that Ad-hNGFβ has a protective effect on cochlear spiral ganglion cells after blast exposure and the efficient gene transfer into cochlea had been achieved without toxicity. 相似文献
27.
M. J. R. C Alles M. A. der Gaag R. J. Stokroos 《European archives of oto-rhino-laryngology》2006,263(9):791-797
To evaluate the value of clinical trials on intratympanic steroid therapy in Ménière’s disease (MD), idiopathic sudden sensorineural hearing loss (ISSNHL) and rapidly progressive sensorineural hearing loss (RPSNHL). Medline and Pubmed databases from 1966 to present were searched for clinical studies on intra- or transtympanic (cortico)steroid therapy of MD, ISSNHL and RPSNHL. Results were cross-checked with additional databases to obtain a complete data set. Clinical trials were evaluated on the basis of comparability, internal and external validity. Articles were judged using the following questions: was a randomised double-blind controlled trial performed? Which criteria were used to confirm the diagnosis of MD, ISSNHL, RPSNHL? Which therapy was evaluated? How long was the follow-up? Which criteria were used to evaluate the results? Reliable evidence on the efficiency, optimum dosage and administration schedule of intratympanic steroid therapy in MD, ISSNHL and RPSNHL is lacking, therefore further investigation is required. 相似文献
28.
DFNA54, a third locus for low-frequency hearing loss 总被引:1,自引:0,他引:1
Gürtler N Kim Y Mhatre A Schlegel C Mathis A Lalwani AK 《Journal of molecular medicine (Berlin, Germany)》2004,82(11):775-780
Nonsyndromic hereditary hearing impairment (NSHHI) is a highly heterogeneous disorder with more than 90 loci mapped, of which nearly one-half of the responsible genes are identified. In dominant NSSHI hearing loss is typically biased towards the high frequencies while low-frequency hearing loss is unusual. Only two NSHHI loci, DFNA1 and DFNA6/14/38, are associated with predominantly low- frequency loss. We mapped the loci harboring the gene responsible for autosomal dominant low-frequency hearing loss in a multigenerational family. The pedigree of a Swiss family with low-frequency hearing loss was established. Using genomic DNA, DFNA1 and DFNA6/14/38 were excluded by linkage analysis or by direct sequencing of the responsible gene. Genome-wide linkage analysis was performed using commercially available microsatellite markers. Two-point linkage analysis demonstrated linkage to chromosome 5q31, the locus for DFNA15, with a lod score of 6.32 at recombination fraction =0 for marker D5S436. Critical recombinations were seen at markers D5S1972 and D5S410. Sequencing of the corresponding gene POU4F3 yielded no pathogenic mutation segregating with the affected members. In addition to Wolfram syndrome gene 1 (DFNA6/14/38) and diaphanous (DFNA1) there is evidence for a third gene involved in low-frequency hearing loss located at DFNA15. Because of the differences in auditory phenotype and the absence of pathogenic mutation in the coding region of POU4F3 it is likely that there is a second gene in 5q31, designated DFNA54, associated with NSHHI. 相似文献
29.
Ferraris A Rappaport E Santacroce R Pollak E Krantz I Toth S Lysholm F Margaglione M Restagno G Dallapiccola B Surrey S Fortina P 《Human mutation》2002,20(4):312-320
Hereditary hearing loss (HHL) is one of the most common congenital disorders and is highly heterogeneous. Mutations in the connexin 26 (CX26) gene (GJB2) account for about 20% of all cases of childhood deafness, and approach 50% in documented recessive cases of non-syndromic hearing loss. In addition, a single mitochondrial DNA mutation, mt1555A>G, in the 12S rRNA gene (MTRNR1), is associated with familial cases of progressive deafness. Effective screening of populations for HHL necessitates rapid assessment of several of these potential mutation sites. Pyrosequencing links a DNA synthesis protocol for determining sequence to an enzyme cascade that generates light whenever pyrophosphate is released during primer strand elongation. We assessed the ability of Pyrosequencing to detect common mutations causing HHL. Detection of the most common CX26 mutations in individuals of Caucasian (35delG), Ashkenazi (167delT), and Asian (235delC, V37I) descent was confirmed by Pyrosequencing. A total of 41 different mutations in the CX26 gene and the mitochondrial mt1555A>G mutation were confirmed. Genotyping of up to six different adjacent mutations was achieved, including simultaneous detection of 35delG and 167delT. Accurate and reproducible results were achieved taking advantage of assay flexibility and experimental conditions easily optimized for a high degree of standardization and cost-effectiveness. The standardized sample preparation steps, including target amplification by PCR and preparation of single-stranded template combined with automated sequence reaction and automated genotype scoring, positions this approach as a potentially high throughput platform for SNP/mutation genotyping in a clinical laboratory setting. . 相似文献
30.
A novel C202F mutation in the connexin26 gene (GJB2) associated with autosomal dominant isolated hearing loss
下载免费PDF全文
![点击此处可从《Journal of medical genetics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Morlé L Bozon M Alloisio N Latour P Vandenberghe A Plauchu H Collet L Edery P Godet J Lina-Granade G 《Journal of medical genetics》2000,37(5):368-370
Mutations in the GJB2 gene encoding connexin26 (CX26) account for up to 50% of cases of autosomal recessive hearing loss. In contrast, only one GJB2 mutation has been reported to date in an autosomal dominant form of isolated prelingual hearing loss. We report here a novel heterozygous 605G→T mutation in GJB2 in all affected members of a large family with late childhood onset of autosomal dominant isolated hearing loss. The resulting C202F substitution, which lies in the fourth (M4) transmembrane domain of CX26, may impair connexin oligomerisation. Finally, our study suggests that GJB2 should be screened for heterozygous mutations in patients with autosomal dominant isolated hearing impairment, whatever the severity of the disease.
Keywords: C202F mutation; connexin26 gene (GJB2); autosomal dominant hearing loss 相似文献
Keywords: C202F mutation; connexin26 gene (GJB2); autosomal dominant hearing loss 相似文献