全文获取类型
收费全文 | 386篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 13篇 |
妇产科学 | 102篇 |
基础医学 | 15篇 |
口腔科学 | 12篇 |
临床医学 | 90篇 |
内科学 | 32篇 |
神经病学 | 29篇 |
特种医学 | 26篇 |
外科学 | 18篇 |
综合类 | 10篇 |
预防医学 | 28篇 |
药学 | 10篇 |
肿瘤学 | 10篇 |
出版年
2021年 | 9篇 |
2019年 | 12篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2013年 | 22篇 |
2012年 | 22篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 11篇 |
2006年 | 6篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 11篇 |
2002年 | 8篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 5篇 |
1995年 | 2篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 12篇 |
1985年 | 13篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1981年 | 2篇 |
1979年 | 7篇 |
1978年 | 4篇 |
1977年 | 5篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 11篇 |
1972年 | 8篇 |
1971年 | 3篇 |
1969年 | 5篇 |
1967年 | 1篇 |
1966年 | 4篇 |
1960年 | 1篇 |
1940年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有396条查询结果,搜索用时 15 毫秒
1.
Dr. E. Mietzsch M. Koch M. Schaldach J. Werner B. Bellenberg K. U. Wentz 《Medical & biological engineering & computing》1998,36(6):673-678
The application of spin-echo magnetic resonance imaging sequences on non-invasive temperature imaging for temperature mapping
of human limbs is investigated. In an in vitro expriment performed on a meat sample, the equilibrium magnetisation P and the
spin-lattice relaxation time T1 are calculated from the values for the repetition time TR and the signal intensities obtained by a spin-echo sequence at
different tissue temperatures tures as measured by a fibre-optic probe. T1 is linearly correlated to the tissue temperature, and P is linearly correlated to the reciprocal value of the absolute temperature.
Both effects, taken together, lead to a non-linear dependency of the signal intensity on temperature. Therefore a TR leading
to maximum temperature dependency of the signal intensity is calculated and used in the futher experiments. In the in vivo
experiments, the lower legs of two volunteers are cooled from outside. Images are acquired with a spin-echo sequence (1.5T,
TR=1200 ms, TE=10 ms). A rise in signal intensity in the muscle with falling skin temperature is observed, particularly in
more peripheral muscle layers. This study shows that spin-echo sequences can be used to monitor temperature changes and temperature
differences in living muscle tissue. 相似文献
2.
3.
4.
Chuyuan Wang Patricia Solís Lily Villa Nayan Khare Elizabeth A. Wentz Aaron Gettel 《Journal of urban health》2021,98(3):344
The objective of the present study was to examine the effects of a confluence of demographic, socioeconomic, housing, and environmental factors that systematically contribute to heat-related morbidity in Maricopa County, Arizona, from theoretical, empirical, and spatial perspectives. The present study utilized ordinary least squares (OLS) regression and multiscale geographically weighted regression (MGWR) to analyze health data, U.S. census data, and remotely sensed data. The results suggested that the MGWR model showed a significant improvement in goodness of fit over the OLS regression model, which implies that spatial heterogeneity is an essential factor that influences the relationship between these factors. Populations of people aged 65+, Hispanic people, disabled people, people who do not own vehicles, and housing occupancy rate have much stronger local effects than other variables. These findings can be used to inform and educate local residents, communities, stakeholders, city managers, and urban planners in their ongoing and extensive efforts to mitigate the negative impacts of extreme heat on human health in Maricopa County. 相似文献
5.
An initiative by the North West Thames Regional Information Technology Agency has resulted in the provision of some 30 CD-ROM drives and copies of the MEDLINE database in National Health Service libraries. The development of the scheme and its implementation are described and future developments outlined. 相似文献
6.
Karen L. Durinzi Anne Colston Wentz Erwin M. Saniga Deborah E. Johnson Susan E. Lanzendorf 《Journal of assisted reproduction and genetics》1997,14(4):199-204
Purpose:
Our purpose was (1) to determine if in vitro maturation of unstimulated oocytes could be improved with the addition of urofollitropin;
(2) to evaluate the output of estradiol, testosterone, progesterone, and androstenedione by the cultured oocyte-cumulus complex;
and (3) to ascertain if steroid hormone production of the oocyte-cumulus complex correlates with final oocyte maturation stage.
Methods:
Fifty-eight immature oocytes were obtained from 11 regularly cycling women undergoing oophorectomy. The oocyte-cumulus complexes
were randomly assigned to control medium (Ham’s F-10 supplemented with 7.5% fetal bovine serum) or test medium (control medium
supplemented with 75 mIU/ml of urofollitropin).
Results:
(1) The addition of urofollitropin to oocyte culture medium does not significantly increase the ability of the oocyte to achieve
the metaphase II stage; (2) the addition of urofollitropin significantly increases the production of progesterone, testosterone,
and androstenedione by the oocyte-cumulus complex; and (3) there is no difference in the production of estradiol, progesterone,
testosterone, and androstenedione by the oocyte-cumulus complex at the germinal vesicle, metaphase I or metaphase II stage
of oocyte maturation.
Conclusions:
This information is of importance in the use of oophorectomy specimens for patients who must undergo an oophorectomy but desire
to attempt pregnancy using their oocytes, in the use of oophorectomy specimens for donor oocytes, or for patients undergoing
in vitro fertilization using immature oocyte collection. 相似文献
7.
The influence of oocyte maturity and embryo quality on pregnancy rate in a program for in vitro fertilization-embryo transfer 总被引:6,自引:0,他引:6
G A Hill M Freeman M C Bastias B J Rogers C M Herbert K G Osteen A C Wentz 《Fertility and sterility》1989,52(5):801-806
An important factor influencing the pregnancy rate after in vitro fertilization-embryo transfer (IVF-ET) appears to be the number of embryos transferred to the uterus. In this study, the influence of oocyte maturity and embryo quality on pregnancy rate was assessed in patients undergoing IVF-ET. Ovarian hyperstimulation was performed by human menopausal gonadotropin (hMG [n = 29]), clomiphene citrate (CC)/hMG (n = 81), and hMG/follicle-stimulating hormone (FSH [n = 13]) protocols. Oocyte maturity was graded on a scale from 1 to 5 based on the morphology of the ooplasm, cumulus mass, corona radiata, and membrana granulosa cells. Embryos were graded according to the symmetry of the blastomeres and the presence or absence of fragmentation. Mature preovulatory oocytes yielded the highest fertilization rates. No differences were found among the protocols in terms of fertilization rate, embryo quality, or pregnancy rate. When all protocols were combined, patients who conceived had a significantly higher number of embryos transferred than those who did not conceive (3.6 +/- 0.1 [mean = SEM] versus 2.7 +/- 0.1). When embryo quality was compared, there was no difference in the number of "B" embryos transferred between patients who conceived and those who did not (1.2 +/- 0.2 versus 1.2 +/- 0.1), but the patients who conceived had significantly more "A" embryos transferred (1.6 +/- 0.3 versus 0.8 +/- 0.1). These data suggest that the treatment protocol did not determine embryo quality. Furthermore, the increase in pregnancy rates seen with an increase in embryos transferred is the result of the transfer of more "A" embryos. 相似文献
8.
In an attempt to identify oocytes at risk for polypronuclear fertilization, follicular fluids were obtained retrospectively that contained oocytes that fertilized normally and abnormally. Whenever possible, each patient served as her own control during the same stimulation cycle. Twenty-six of 169 patients had oocytes that became polypronuclear, and of those 26, 21 had oocytes that fertilized and cleaved normally. Follicular fluids were analyzed for estradiol, progesterone, androstenedione, transferrin, and insulin. Insulin levels were noted to be significantly elevated (P less than 0.05) in the polypronuclear group when compropose that insulin, a known growth factor for granulosa cells cultured in vitro, when present in excessive concentrations may predispose to polypronuclear fertilization. 相似文献
9.
IntroductionChildren and adolescents with autism spectrum disorder (ASD) appear to be at greater risk of excess weight gain. The aim of this systematic review and meta-analysis was to examine whether children with ASD have a greater prevalence of obesity and whether the prevalence of ASD is higher in children with obesity.MethodsWe conducted a systematic search on PubMed, Scopus, and PsychINFO until May 21, 2021. We used the meta package in the R in order to calculate the pooled prevalence and relative risk of obesity in children with ASD.ResultsWe found 20 eligible studies investigating the prevalence of obesity in children with ASD, with the prevalence ranging from 7.9 to 31.8% and from 1.4 to 23.6% among controls. All but three studies originated from the USA. The proportion of children with obesity in ASD populations was 17% (95% confidence interval [CI]: 13–22). The relative risk of obesity in children with ASD compared with control children was 1.58 (95% CI: 1.34–1.86). There were no controlled studies reporting on the prevalence of ASD in children with obesity.ConclusionChildren and adolescents with ASD have a higher prevalence of obesity than healthy controls. There is a need for further prevalence studies of obesity in children with ASD, especially outside the USA, since the few European studies carried out have failed to show a significant difference between obesity prevalence in children with and without ASD. There is no knowledge at all regarding the prevalence of ASD among children with obesity. 相似文献
10.