全文获取类型
收费全文 | 554篇 |
免费 | 29篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 56篇 |
妇产科学 | 3篇 |
基础医学 | 77篇 |
口腔科学 | 16篇 |
临床医学 | 81篇 |
内科学 | 146篇 |
皮肤病学 | 13篇 |
神经病学 | 12篇 |
特种医学 | 107篇 |
外科学 | 29篇 |
综合类 | 8篇 |
预防医学 | 21篇 |
药学 | 29篇 |
肿瘤学 | 16篇 |
出版年
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 6篇 |
2014年 | 9篇 |
2013年 | 19篇 |
2012年 | 5篇 |
2011年 | 21篇 |
2010年 | 24篇 |
2009年 | 18篇 |
2008年 | 10篇 |
2007年 | 24篇 |
2006年 | 13篇 |
2005年 | 20篇 |
2004年 | 9篇 |
2003年 | 12篇 |
2002年 | 10篇 |
2001年 | 11篇 |
2000年 | 10篇 |
1999年 | 18篇 |
1998年 | 46篇 |
1997年 | 45篇 |
1996年 | 35篇 |
1995年 | 19篇 |
1994年 | 25篇 |
1993年 | 16篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 12篇 |
1988年 | 28篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 14篇 |
1981年 | 9篇 |
1980年 | 6篇 |
1978年 | 3篇 |
1977年 | 5篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1954年 | 2篇 |
1948年 | 1篇 |
1947年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有615条查询结果,搜索用时 15 毫秒
1.
Rupture of the distal biceps tendon: evaluation with MR imaging 总被引:2,自引:0,他引:2
2.
Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
3.
4.
García-González MA Lanas A Savelkoul PH Santolaria S Benito R Crusius JB Peña AS 《Clinical and experimental immunology》2003,134(3):525-531
Cytokine genes taking part in the immunological response to Helicobacter pylori infection are good candidates to study for genetic predisposition to duodenal ulcer disease (DU). Among cytokines, interleukin (IL)-1beta and its natural specific inhibitor, the interleukin-1 receptor antagonist, are cytokines that play a key role in regulating gastric acid secretion and modulating the immune response in the gastrointestinal mucosa. We aimed to investigate whether polymorphisms in the IL-1B and IL-1RN genes are involved in the susceptibility to duodenal ulcer. DNA from 131 unrelated Spanish Caucasian patients with DU and 105 ethnically matched healthy controls was typed for the IL-1B-511, IL-1B-31, and IL-1B + 3954 gene polymorphisms, and the VNTR polymorphism in intron 2 of the IL-1RN gene by polymerase chain reaction (PCR)-based methods and TaqMan assays. H. pylori status and non-steroidal anti-inflammatory drugs (NSAIDs) use was determined in all patients and controls. Logistic regression analysis identified H. pylori infection (OR: 9.74; 95%CI = 3.53-26.89) and NSAIDs use (OR: 8.82; 95%CI = 3.51-22.17) as independent risk factors for DU. In addition, the simultaneous carriage of IL-1RN*2, IL-1B-511*C, IL-1B-31*T and IL-1B + 3954*C alleles was a genetic risk factor for DU in patients with H. pylori infection (OR: 3.22; 95%CI = 1.09-9.47). No significant differences in IL-1RN and IL-1B genotypes were found when patients were categorized according to gender, age of onset, smoking habit, NSAIDs use, type of complication and positive family history. Our results provide further evidence that host genetic factors play a key role in the pathogenesis of duodenal ulcer. 相似文献
5.
6.
It is well recognized that the ability to cryopreserve unfertilizedhuman oocytes would make a significant contribution to infertilitytreatment. However, despite considerable interest, very fewsuccessful pregnancies have arisen from cryopreserved oocytesafter thawing, insemination and transfer of the subsequent embryo.The reasons for this lack of progress may well result from adearth of information on how the various biophysical changesduring a cryopreservation regimen affect human oocyte function.Recently, fundamental studies on the effects of cooling, membranepermeability, cryoprotectant addition and ice formation havebeen performed on human oocytes by a number of groups, and theseform the basis of the current review. It is likely that successfulhuman oocyte cryopreservation will only follow once these factorsare fully understood, but the existing base of knowledge shouldprovide a platform for further improvements in the techniquescurrently employed. 相似文献
7.
8.
Bayley JP Baggen JM van der Pouw-Kraan T Crusius JB Huizinga TW Verweij CL 《Tissue antigens》2003,62(2):170-174
Cell trafficking into the rheumatoid synovium is thought to play an important role in the inflammation seen in rheumatoid arthritis. Chemokine receptors play a central role in this process, and several common variants are known, including the CCR2 variant, CCR2-64I, and two variants of the CX3CR1 gene, V249I and T280M. All three variants result in functional amino acid substitutions. We studied the association of these chemokine receptor variants with susceptibility to and severity of rheumatoid arthritis in two Dutch patient populations; 282 consecutive rheumatoid arthritis patients from a rheumatology outpatient clinic, and a cohort of 101 female rheumatoid arthritis patients, followed closely for a 12-year period, from whom hand and feet X-rays taken at three year intervals were scored and analyzed in this study. Although there was a trend towards increased severity of disease in patients carrying CX3CR1 variants, this was not independent of known risk factors. We found no evidence for a significant independent role for the CCR2 and CX3CR1 variants in the susceptibility to or severity of rheumatoid arthritis. 相似文献
9.
KM Kanal NJ Hangiandreou AM Sykes HE Eklund PA Araoz JA Leon BJ Erickson 《Journal of digital imaging》2002,14(1):30-37
The aims of this work were to measure the accuracy of one continuous speech recognition product and dependence on the speaker's
gender and status as a native or nonnative English speaker, and evaluate the product's potential for routine use in transcribing
radiology reports. IBM MedSpeak/Radiology software, version 1.1 was evaluated by 6 speakers. Two were nonnative English speakers,
and 3 were men. Each speaker dictated a set of 12 reports. The reports included neurologic and body imaging examinations performed
with 6 different modalities. The dictated and original report texts were compared, and error rates for overall, significant,
and subtle significant errors were computed. Error rate dependence on modality, native English speaker status, and gender
were evaluated by performing ttests. The overall error rate was 10.3 +/- 3.3%. No difference in accuracy between men and women
was found; however, significant differences were seen for overall and significant errors when comparing native and nonnative
English speakers (P = .009 and P = .008, respectively). The speech recognition software is approximately 90% accurate, and
while practical implementation issues (rather than accuracy) currently limit routine use of this product throughout a radiology
practice, application in niche areas such as the emergency room currently is being pursued. This methodology provides a convenient
way to compare the initial accuracy of different speech recognition products, and changes in accuracy over time, in a detailed
and sensitive manner. 相似文献
10.
The association of certain human papillomavirus (HPV) types with malignancies of the anogenital tract is well established. The virus type most frequently associated with cellular transformation is HPV 16, as has been shown in epidemiological studies. Its transforming capacity has also been demonstrated in many in vitro cell transformation experiments. The most potent oncogenes of HPV 16 are the E6 and E7 proteins, but the E5 protein, whose homologue is the main oncogene of bovine papillomavirus, has recently been identified as an oncogene also for HPV. On the basis of epidemiological and clinical data from tumor material as well as from in vitro data it has been suggested, that the HPV 16 E5 protein would have a function at the early stages of cervical carcinogenesis. The E5 protein enhances growth factor-mediated signal transduction to the nucleus and consequently augments cellular proliferation. Expression of the E5 protein enables the infected cell to escape growth control provided by surrounding cells by inhibiting gap junctional intercellular communication in epithelial cells. This viral oncogene seems to interfere with the control mechanisms of cellular growth and proliferation and thus facilitate the function of the E6 and E7 proteins and further steps towards epithelial cell transformation. 相似文献