全文获取类型
收费全文 | 172篇 |
免费 | 8篇 |
专业分类
儿科学 | 4篇 |
妇产科学 | 7篇 |
基础医学 | 20篇 |
临床医学 | 4篇 |
内科学 | 16篇 |
神经病学 | 53篇 |
外科学 | 11篇 |
预防医学 | 39篇 |
眼科学 | 1篇 |
药学 | 9篇 |
肿瘤学 | 16篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2012年 | 6篇 |
2011年 | 14篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 9篇 |
2006年 | 3篇 |
2005年 | 3篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1997年 | 2篇 |
1992年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1972年 | 4篇 |
1970年 | 1篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1965年 | 4篇 |
1964年 | 3篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1960年 | 3篇 |
1959年 | 2篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
1952年 | 1篇 |
1947年 | 1篇 |
1886年 | 1篇 |
排序方式: 共有180条查询结果,搜索用时 15 毫秒
1.
To study the spread of sexually transmitted diseases (STDs) using social/sexual mixing models, one must have quantitative information about sexual mixing. An unavoidable complication in gathering such information by survey is that members of the surveyed population will almost certainly have sexual contacts outside that population. The number of these outsiders may be substantial and, hence, important for the modelling process. In this paper, we develop a mark-recapture model for estimating the size of the population at risk for contracting a STD due to direct sexual contact with a specified population targeted by a survey. This mark-recapture methodology provides a reliable method of estimating the number of outsiders. Because not everyone in the targeted population may be sexually active, the size of the sexually active subset, used as the number marked in our tag-recapture formulation, must be estimated, which introduces extra variability. We derive an estimator of the variance of the estimated total number at risk that accounts for this extra variability and an expression for the bias of that estimator. We extend the methodology to stratified surveys and illustrate its use with data collected from a population of university undergraduates to estimate sexual mixing parameters of a deterministic model of the spread of STDs. 相似文献
2.
G. E. Umbach C. Holzki U. Perschmann H. G. Schnürch H. G. Bender 《Archives of gynecology and obstetrics》1987,242(1-4):349-350
Ohne Zusammenfassung 相似文献
3.
A two-stage approach was used to analyze Problem 2 simulated data from Genetic Analysis Workshop 11. In the first stage, we tested for linkage with the Haseman-Elston test in SIBPAL. Markers that were significant in the first stage were followed up with two types of association tests. These association tests differ in the type of family information used: 1) parental transmissions to affected children or 2) differences in marker allele frequencies between affected and unaffected siblings. We also explored how the conclusions changed when different sampling strategies were used. Of particular interest was whether the entire data set should be used to test for both linkage and association or whether the data set should be halved to allow for replication of the initial association results. 相似文献
4.
Choosing a retrospective design to assess joint genetic and environmental contributions to risk 总被引:11,自引:0,他引:11
The authors consider issues that should be weighed when designing a retrospective study in which a focus of interest is the joint role of genetic and environmental factors in causing a disease. In place of the classical case-control design, in which controls are sampled from the same population that gives rise to the cases, one could study cases only. The case-only approach can be usefully extended by genotyping the two biologic parents of each case and in effect letting the parental genotype data provide the genetic control. Alternatively, one could carry out a case-control study in which the controls are siblings or cousins of the cases and inference is based on within-family parameters. The authors compare and contrast the parameters that can be estimated and the assumptions that must be made when each of these designs is used. The investigator must also consider certain practical issues, such as the availability of parents or sibling controls. 相似文献
5.
Günter E. Umbach Judith Poethen Heino v. Matthiessen Hans Georg Bender Ursula Koldovsky 《Journal of cancer research and clinical oncology》1985,110(3):234-237
Summary Tumor samples from 74 patients with gynecologic malignancies including breast cancer were processed in a soft agar colony-forming assay. None of the samples resulted in a pure single cell suspension. Of the 10 samples meeting our criteria of evaluability for chemosensitivity testing, only 5 samples showed in vitro sensitivity to any drug. Of the 3 evaluable correlations between in vitro and in vivo results, 2 were correct. Due to the low rate of evaluable samples the assay has only limited value in the assignment of chemotherapeutic drugs for patients treated at our institution.This work was supported in part by the Gesellschaft zur Bekämpfung der Krebskrankheiten Nordrhein-Westfalen 相似文献
6.
Samuel M. Goldman MD MPH Freya Kamel PhD G. Webster Ross MD Sarah A. Jewell MD MPH Connie Marras MD PhD Jane A. Hoppin ScD David M. Umbach PhD Grace S. Bhudhikanok PhD Cheryl Meng MS Monica Korell MPH Kathleen Comyns MPH Robert A. Hauser MD Joseph Jankovic MD Stewart A. Factor DO Susan Bressman MD Kelly E. Lyons PhD Dale P. Sandler PhD J. William Langston MD Caroline M. Tanner MD PhD 《Movement disorders》2014,29(9):1171-1180
Increased gut permeability, inflammation, and colonic α‐synuclein pathology are present in early Parkinson's disease (PD) and have been proposed to contribute to PD pathogenesis. Peptidoglycan is a structural component of the bacterial cell wall. Peptidoglycan recognition proteins (PGRPs) maintain healthy gut microbial flora by regulating the immune response to both commensal and harmful bacteria. We tested the hypothesis that variants in genes that encode PGRPs are associated with PD risk. Participants in two independent case‐control studies were genotyped for 30 single‐nucleotide polymorphisms (SNPs) in the four PGLYRP genes. Using logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for potential confounding variables, we conducted analyses in each study, separately and pooled. One SNP failed the assay, and three had little to no variation. The ORs were similar in both study populations. In pooled analyses, three of seven PGLYRP2 SNPs (rs3813135, rs733731, rs892145), one of five PGLYRP3 SNPs (rs2987763), and six of nine PGLYRP4 SNPs (rs10888557, rs12063091, rs3006440, rs3006448, rs3006458, and rs3014864) were significantly associated with PD risk. Association was strongest for PGLYRP4 5'untranslated region (UTR) SNP rs10888557 (GG reference, CG OR 0.6 [95%CI 0.4‐0.9], CC OR 0.15 [95%CI 0.04‐0.6]; log‐additive P‐trend, 0.0004). Common variants in PGLYRP genes are associated with PD risk in two independent studies. These results require replication, but they are consistent with hypotheses of a causative role for the gut microbiota and gastrointestinal immune response in PD. © 2014 International Parkinson and Movement Disorder Society 相似文献
7.
Vitamin D receptor polymorphisms and prostate cancer 总被引:2,自引:0,他引:2
Prostate cancer is a common disease, yet determinants of prostate cancer risk remain largely unidentified. Low circulating levels of 1, 25-dihydroxy vitamin D (1,25-D) have been implicated as a risk factor for prostate cancer. In addition, 1,25-D exhibits significant antineoplastic properties both in vitro and in vivo, and these antiproliferative effects appear to be mediated through the vitamin D receptor (VDR). The VDR has a number of common polymorphisms, including a TaqI restriction fragment length polymorphism in exon 9 and a poly(A) length polymorphism in the 3'-untranslated region. Previous studies have found an association between the TaqI T allele or poly(A) L allele and prostate cancer. To further investigate the putative link between VDR polymorphisms and prostate cancer, we conducted a case-control study of prostate cancer patients from the Piedmont region of North Carolina. Using polymerase chain reaction-based techniques on DNA extracted from peripheral blood, we genotyped 77 cases (70 white, seven black) and 183 controls (169 white, 14 black) for the TaqI and poly(A) alleles. We report here an overall lack of association between either the TaqI or poly(A) genotype and prostate cancer odds ratio (OR)=1.4, 95% confidence interval (CI)=0.7-2.8; and OR=1.2, 95% CI=0.6-2.5, respectively). Using a case-case analysis, we tested whether these polymorphisms might be associated with more advanced disease but found no statistically significant association for the TaqI T or poly(A) L allele (OR=2.5, 95% CI=0.3-21.7; OR=2.8, 95% CI=0.3-23.8, respectively). We report strong evidence of linkage disequilibrium between the TaqI and poly(A) polymorphisms (P < 0.0001), with whites demonstrating stronger linkage disequilibrium than blacks (D=0.24 vs. D=0.18). 相似文献
8.
Kirrane EF Hoppin JA Kamel F Umbach DM Boyes WK Deroos AJ Alavanja M Sandler DP 《American journal of epidemiology》2005,161(11):1020-1029
Retinal degeneration is the leading cause of visual impairment in older adults. An association between retinal degeneration and fungicide use was observed previously among farmer pesticide applicators in the Agricultural Health Study, a large study of farm families from Iowa and North Carolina. The objective of this investigation was to determine whether wives of these farmer pesticide applicators were at increased risk of retinal degeneration. Self-reported cross-sectional data obtained via questionnaire between 1993 and 1997 from 31,173 wives were used. Associations of specific pesticides and groups of pesticides based on function (fungicides, herbicides, insecticides, and fumigants) or chemical structure (organophosphates, organochlorines, and carbamates) with eye disorders were evaluated using logistic and hierarchical logistic regression analyses. Self-reported retinal degeneration was associated with the wife's fungicide use (odds ratio = 1.9, 95% confidence interval: 1.2, 3.1) after adjustment for age and state of residence. Specific fungicides that appeared to drive this association were maneb or mancozeb and ziram. No associations between pesticide use and other eye disorders were found. Although these findings for retinal degeneration are based solely on self-reported disease, they are consistent with those reported for farmer pesticide applicators. These findings suggest that exposure to some fungicides and other pesticides may increase the risk of retinal degeneration and warrant further investigation. 相似文献
9.
10.