首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   433篇
  免费   31篇
  国内免费   13篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   8篇
基础医学   33篇
口腔科学   17篇
临床医学   54篇
内科学   97篇
皮肤病学   17篇
神经病学   2篇
特种医学   127篇
外科学   22篇
综合类   10篇
预防医学   17篇
眼科学   3篇
药学   13篇
肿瘤学   40篇
  2023年   1篇
  2021年   4篇
  2020年   2篇
  2019年   3篇
  2018年   9篇
  2017年   4篇
  2016年   5篇
  2015年   12篇
  2014年   5篇
  2013年   20篇
  2012年   6篇
  2011年   7篇
  2010年   14篇
  2009年   25篇
  2008年   6篇
  2007年   24篇
  2006年   12篇
  2005年   8篇
  2004年   2篇
  2003年   3篇
  2002年   5篇
  2001年   7篇
  2000年   2篇
  1999年   7篇
  1998年   47篇
  1997年   45篇
  1996年   22篇
  1995年   23篇
  1994年   12篇
  1993年   12篇
  1992年   2篇
  1991年   4篇
  1990年   8篇
  1989年   10篇
  1988年   13篇
  1987年   13篇
  1986年   11篇
  1985年   10篇
  1984年   9篇
  1983年   8篇
  1982年   6篇
  1981年   6篇
  1980年   9篇
  1979年   3篇
  1977年   3篇
  1976年   2篇
  1975年   6篇
排序方式: 共有477条查询结果,搜索用时 62 毫秒
91.
92.
We report two peculiar cases that were observed in two communities of Anambra State, South East Nigeria. The first case was a woman of 44 with a history of blood transfusion from a donor of questionable HIV status. A pint of blood was transfused in a private Hospital on the 15 th January, 2000. She has had no form of antiviral therapy until 22nd April, 2008 when she came to the hospital for routine medical check up. Her HIV result came out confirmed positive while that of her husband came out negative. She has had active sexual life with her husband in the previous eight years as they have had some difficulties in getting their desired extra two children having earlier gotten a boy and a girl. The second case involves a family of six. A couple with four children of ages about 6 months, 2 years, 3 years and 5 years. The youngest, a female presented with fever and multiple lymphadenopathy. She tested HIV positive and so was her mother and her second sibling. But her father and two other siblings remained negative at post three and six months intervals from their very first test date with us. These reported cases appear to go contrary to earlier formed opinion on HIV transmission. We support the opinion on a naturally, occurring substance, APOBEC3G which possibly confers permanent immunity against the HIV virus. We recommend clinical trials of the characterized APOBEC3G as a vaccine for non HIV infected persons of all ages and to people living with as a therapeutic drug.  相似文献   
93.

Background

Previous studies have reported on adverse neonatal outcomes associated with parity and maternal age. Many of these studies have relied on cross-sectional data, from which drawing causal inference is complex. We explore the associations between parity/maternal age and adverse neonatal outcomes using data from cohort studies conducted in low- and middle-income countries (LMIC).

Methods

Data from 14 cohort studies were included. Parity (nulliparous, parity 1-2, parity ≥3) and maternal age (<18 years, 18-<35 years, ≥35 years) categories were matched with each other to create exposure categories, with those who are parity 1-2 and age 18-<35 years as the reference. Outcomes included small-for-gestational-age (SGA), preterm, neonatal and infant mortality. Adjusted odds ratios (aOR) were calculated per study and meta-analyzed.

Results

Nulliparous, age <18 year women, compared with women who were parity 1-2 and age 18-<35 years had the highest odds of SGA (pooled adjusted OR: 1.80), preterm (pooled aOR: 1.52), neonatal mortality (pooled aOR: 2.07), and infant mortality (pooled aOR: 1.49). Increased odds were also noted for SGA and neonatal mortality for nulliparous/age 18-<35 years, preterm, neonatal, and infant mortality for parity ≥3/age 18-<35 years, and preterm and neonatal mortality for parity ≥3/≥35 years.

Conclusions

Nulliparous women <18 years of age have the highest odds of adverse neonatal outcomes. Family planning has traditionally been the least successful in addressing young age as a risk factor; a renewed focus must be placed on finding effective interventions that delay age at first birth. Higher odds of adverse outcomes are also seen among parity ≥3 / age ≥35 mothers, suggesting that reproductive health interventions need to address the entirety of a woman’s reproductive period.

Funding

Funding was provided by the Bill & Melinda Gates Foundation (810-2054) by a grant to the US Fund for UNICEF to support the activities of the Child Health Epidemiology Reference Group.
  相似文献   
94.
Oral opportunistic infections developing secondary to human immunodeficiency virus (HIV) infection have been reported from the early days of the epidemic and have been classified by both the EC-Clearinghouse and the World Health Organisation (WHO). Among the fungal infections, oral candidiasis, presenting in African HIV-infected patients has been sporadically documented. We review the literature with respect to candidal carriage, oral candidiasis prevalence and the predictive value of oral candidiasis for a diagnosis of underlying HIV disease in African HIV-infected patients. The use of oral candidiasis as a marker of disease progression, the species of yeasts isolated from the oral cavity in Africa and the resistance of the yeasts to antifungal agents and treatment regimens are discussed. Orofacial lesions as manifestations of the systemic mycoses are rarely seen in isolation and few cases are reported in the literature from Africa. In spite of the high incidence of noma, tuberculosis, chronic osteomyelitis and syphilis in Africa, surprisingly there have been very few reported cases of the oral manifestations of these diseases in HIV-positive individuals. Orofacial disease in HIV-infected patients is associated with marked morbidity, which is compounded by malnutrition. The authors indicate specific research areas, initially directed at the most effective management strategies, which would complete data in this important area.  相似文献   
95.
Objective  We investigated the application of high-resolution microarray-based comparative genomic hybridisation (array CGH) on a fetus showing increased nuchal translucency (NT).
Design  Case study.
Setting  Tertiary referral obstetrics unit.
Sample  Pregnant woman attended the antenatal clinic.
Methods  Conventional karyotyping and genetic test was carried out for the alpha-globin gene. High-resolution array CGH using the high-density 244K Agilent microarray was performed on fetal blood sample by cordocentesis to investigate the possibility of any genomic imbalance.
Main outcome measures  Detection of chromosomal abnormality.
Results  Karyotyping analysis showed 46,XY. Molecular genetic diagnosis confirms the fetus has Hb-H constant spring disease but cannot explain the increased NT to 3.2 mm. Array CGH analysis discovered a 1.32-Mb microdeletion on chromosome 16p13.11. Deletion at 16p13.11 has been implicated to predispose to autism and/or mental retardation. Baby was delivered at 40 weeks of gestation, and follow up was carried out at 3 months of age without sign of mental retardation/developmental delay.
Conclusions  This case study demonstrated that array CGH can accurately calibrate the size and identify de novo interstitial chromosome imbalances. However, the presence of chromosome copy variants with unknown clinical significance currently limits its wider scale application in prenatal diagnosis and needs further investigations.  相似文献   
96.
Effects of elbow positioning on grip strength and its between-day reliability of measurement were tested bilaterally in 30 healthy adults. Grip strength was measured twice with a Jamar dynamometer at 0°, 30°, 60°, 90° and 120° of elbow flexion one week apart. Intraclass correlation coefficient model(1,1) was > 0.987 for each test, and limits of agreement reveal narrow ranges of the 95% confidence intervals for each test, which reflect good between-day reliability for these measurements in both absolute and relative terms. Grip strength at 120° was significantly lower than all other positions on both sides (p < 0.001), whereas the grip strength at 90° was highest among all positions tested. The grip strengths at 0°, 30° and 60° were, in general, 0.5-3% lower than the measurements taken at 90° of elbow flexion, but the differences were not statistically significant. These findings suggest that between-day comparison of grip strength is valid and reproducible in the same testing position, and 120° of elbow flexion is not a desirable position for grip strengthening exercise. The differences in grip strength can be explained by the length-tension relationship and the clinical implications for these findings are discussed.  相似文献   
97.
98.
99.
A prospectively controlled pilot study of 100 patients undergoing an invasive radiological procedure was undertaken to test patients' acceptance of risk disclosure and whether this increases anxiety and rate of procedure cancellation. Two sheets with differing amounts of information on adverse outcome were randomly allocated and patients provided a graded response to statements following the procedure. Eighty-one completed questionnaires were received (brief sheet n= 40; long sheet n= 41). There were 19 non-compliers with main causes either due to lack of interest or problems such as language difficulties, visual impairment and dementia. There were no significant differences between the two groups with respect to subjective anxiety caused by the information or risk of procedure cancellation. This preliminary work has shown that information sheets are well accepted and provide a simple, standardized format for risk disclosure.  相似文献   
100.
It would appear that it has become almost common practice to regard arachidonic acid (AA) as the sole precursor of eicosanoids. The fact that both dihomogamma-linolenic acid (DGLA) and eicosapentaenoic acid (EPA) give rise to distinct families of eicosanoids is commonly almost completely ignored. Elevated tissue levels of AA eicosanoids have been found in and have been implicated in the etiology of a number of diseases. Drugs which selectively block AA mobilization or its eicosanoid metabolism have therefore been developed for therapeutic use in these conditions. The fact that such drugs will also simultaneously block the eicosanoid metabolism from DGLA as well as from EPA is also commonly ignored. It is suggested that the profoundly adverse side-effects displayed by some of these drugs, resulting in some instances in their withdrawal from use, could be the direct result of their concomitant action of interfering with the eicosanoid metabolism of DGLA and EPA. It is further suggested that, before the interactions between the eicosanoids derived from AA and those derived from DGLA and EPA are understood, the use of drugs for the manipulation of AA eicosanoid metabolism in isolation, could be hazardous. This implies that all such drugs currently in use are to be regarded as experimental and provisionally toxic in terms of their effects on the whole system of eicosanoid metabolism. Thus even drugs which have been passed by the FDA and similar Drug Control Councils require total re-evaluation especially in view of the fact that the non-steroidal anti-inflammatory drugs are often prescribed for chronic conditions which require therapy for several years.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号