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   285篇
  免费   33篇
儿科学   2篇
妇产科学   44篇
基础医学   43篇
口腔科学   22篇
临床医学   15篇
内科学   80篇
皮肤病学   22篇
神经病学   3篇
特种医学   2篇
外科学   26篇
综合类   3篇
预防医学   41篇
眼科学   1篇
药学   11篇
肿瘤学   3篇
  2022年   1篇
  2021年   2篇
  2020年   2篇
  2019年   4篇
  2018年   5篇
  2017年   14篇
  2016年   9篇
  2015年   6篇
  2014年   10篇
  2013年   20篇
  2012年   23篇
  2011年   24篇
  2010年   7篇
  2009年   7篇
  2008年   21篇
  2007年   20篇
  2006年   19篇
  2005年   9篇
  2004年   12篇
  2003年   10篇
  2002年   14篇
  2001年   9篇
  2000年   9篇
  1999年   9篇
  1998年   5篇
  1997年   1篇
  1995年   1篇
  1994年   1篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   4篇
  1985年   2篇
  1984年   5篇
  1983年   2篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1975年   1篇
  1974年   2篇
  1973年   2篇
  1971年   1篇
  1969年   2篇
  1968年   1篇
  1967年   1篇
排序方式: 共有318条查询结果,搜索用时 15 毫秒
1.
2.
The human immunodeficiency virus type 1 (HIV-1) DNA PCR results of 94 dried blood spot (DBS) samples on filter paper and corresponding venous blood in EDTA obtained from infants born to HIV-1-seropositive mothers were compared. In addition, the results of HIV-1 DNA PCR on DBS and the HIV-1 RNA PCR from plasma of 70 paired samples were compared. A 100% specificity and a 95% sensitivity for HIV-1 DNA PCR on DBS compared with results for venous blood were observed for the 94 paired samples. The results of the DBS HIV-1 DNA PCR and HIV-1 RNA PCR of 70 corresponding plasma samples correlated perfectly (100%). The DBS HIV-1 DNA PCR method proved reliable for HIV-1 detection.  相似文献   
3.
Placental inflammation and perinatal transmission of HIV-1   总被引:2,自引:0,他引:2  
The effect of placental membrane inflammation on mother-to-child transmission (MTCT) of HIV-1 is reported. Placentas from HIV-1-infected women were examined as part of a perinatal HIV-1 project in Mombasa, Kenya. Polymerase chain reaction analysis was used to test for HIV-1 in the infants at birth and at 6 weeks. The maternal HIV-1 seroprevalence was 13.3% (298 of 2,235). The overall rate of MTCT of HIV-1 was 25.4%; polymerase chain reaction analysis revealed that of the 201 infants 6.0% (12) were already HIV-1-positive at birth (intrauterine transmission) and 19.4% (39) were infected during the peripartum period or in early neonatal life (perinatal transmission). The prevalence of acute chorioamnionitis was 8.8%, that of deciduitis was 10.8%, and that of villitis was 1.6%. Acute chorioamnionitis was independently associated with peripartum HIV-1 transmission but not with in utero MTCT (17.9% vs. 6.7%, respectively; adjusted odds ratio, 3.9; 95% confidence interval, 1.2-12.5; p =.025). Other correlates of perinatal MTCT were presence of HIV in the genital tract and in the baby's oral cavity and a high maternal viral load in peripheral blood. The adjusted population attributable fraction of 12.8% (95% confidence interval, 1.5%-22.8%) indicated that approximately 3% of MTCT could be prevented if acute chorioamnionitis was eliminated. We suggest that further research on the role of antimicrobial treatment in the prevention of chorioamnionitis and the reduction of peripartum MTCT needs to be performed.  相似文献   
4.
5.
Intersections between migration and sex work are underexplored in southern Africa, a region with high internal and cross-border population mobility, and HIV prevalence. Sex work often constitutes an important livelihood activity for migrant women. In 2010, sex workers trained as interviewers conducted cross-sectional surveys with 1,653 female sex workers in Johannesburg (Hillbrow and Sandton), Rustenburg and Cape Town. Most (85.3 %) sex workers were migrants (1396/1636): 39.0 % (638/1636) internal and 46.3 % (758/1636) cross-border. Cross-border migrants had higher education levels, predominately worked part-time, mainly at indoor venues, and earned more per client than other groups. They, however, had 41 % lower health service contact (adjusted odds ratio = 0.59; 95 % confidence interval = 0.40–0.86) and less frequent condom use than non-migrants. Police interaction was similar. Cross-border migrants appear more tenacious in certain aspects of sex work, but require increased health service contact. Migrant-sensitive, sex work-specific health care and health education are needed.  相似文献   
6.
ABSTRACT: BACKGROUND: While the HIV epidemic is levelling off in sub-Saharan Africa, it remains at an unacceptably high level. Young people aged 15-24 years remain particularly vulnerable, resulting in a regional HIV prevalence of 1.4% in young men and 3.3% in young women. This study assesses the effectiveness of a peer-led HIV prevention intervention in secondary schools in Rwanda on young people's sexual behavior, HIV knowledge and attitudes. METHODS: In a non-randomized longitudinal controlled trial, fourteen schools were selected in two neighboring districts: Bugesera (intervention) and Rwamagana (control). Students (n = 1950) in eight intervention and six control schools participated in three surveys (baseline, six and twelve months in the intervention). Analysis was done using linear and logistic regression using generalized estimation equations adjusted for propensity score. RESULTS: The overall retention rate was 72%. Time trends in sexual risk behavior (being sexually active, sex in last six months, condom use at last sex) were not significantly different in students from intervention and control schools, nor was the intervention associated with increased knowledge, perceived severity or perceived susceptibility. It did significantly reduce reported stigma. CONCLUSIONS: Analyzing this and other interventions, we identified several reasons for the observed limited effectiveness of peer education: 1) intervention activities (spreading information) are not tuned to objectives (changing behavior); 2) young people prefer receiving HIV information from other sources than peers; 3) outcome indicators are not adequate and the context of the relationship in which sex occurs. Effectiveness of peer education may increase through integration in holistic interventions and redefining peer educators' role as focal points for sensitization and referral to experts and services. Finally, we argue that a narrow focus on sexual risks will never significantly turn the tide.  相似文献   
7.
Discovery of a cholecystokinin-gastrin-like signaling system in nematodes   总被引:2,自引:0,他引:2  
Members of the cholecystokinin (CCK)/gastrin family of peptides, including the arthropod sulfakinins, and their cognate receptors, play an important role in the regulation of feeding behavior and energy homeostasis. Despite many efforts after the discovery of CCK/gastrin immunoreactivity in nematodes 23 yr ago, the identity of these nematode CCK/gastrin-related peptides has remained a mystery ever since. The Caenorhabditis elegans genome contains two genes with high identity to the mammalian CCK receptors and their invertebrate counterparts, the sulfakinin receptors. By using the potential C. elegans CCK receptors as a fishing hook, we have isolated and identified two CCK-like neuropeptides encoded by neuropeptide-like protein-12 (nlp-12) as the endogenous ligands of these receptors. The neuropeptide-like protein-12 peptides have a very limited neuronal expression pattern, seem to occur in vivo in the unsulfated form, and react specifically with a human CCK-8 antibody. Both receptors and ligands share a high degree of structural similarity with their vertebrate and arthropod counterparts, and also display similar biological activities with respect to digestive enzyme secretion and fat storage. Our data indicate that the gastrin-CCK signaling system was already well established before the divergence of protostomes and deuterostomes.  相似文献   
8.

Background  

Previous studies have indicated that a recently described anaerobic bacterium, Atopobium vaginae is associated with bacterial vaginosis (BV). Thus far the four isolates of this fastidious micro-organism were found to be highly resistant to metronidazole and susceptible for clindamycin, two antibiotics preferred for the treatment of BV.  相似文献   
9.
OBJECTIVE: To obtain baseline information for designing a community-based intervention programme aimed at increasing the cervical cancer screening coverage of women most at risk. METHODS: A population-based survey, using proportional stratified two-stage cluster sampling in Rivas, one of the 16 Departments of Nicaragua. The individuals selected were interviewed at home by one of 26 interviewers, using a structured questionnaire. The questionnaire was designed to elicit (1) knowledge, attitudes and practices concerning sexual and reproductive health and behaviour, (2) risk factors for cervical cancer and (3) the use of health and cervical cancer screening services. RESULTS: A total of 612 men and 634 women participated in the survey. Of the women who had been sexually active at least 3 years, only 41.1% had undergone screening within that period and were considered adequately screened. Correlates of inadequate screening status included low educational level, exclusive use of public health facilities and lack of knowledge about prevention and symptoms of cervical cancer. Negligence, absence of medical problems, fear, lack of knowledge and economic reasons were the main reasons given for not being screened. Reluctance to be screened in the future was related to lack of knowledge of the disease, inadequate screening status, older age and low educational level. CONCLUSIONS: The current screening programme is not effective in reaching the majority of the population. Complementary activities such as education and information, as well as a more pro-active approach to invite women for screening are necessary.  相似文献   
10.
This cluster-randomized study aimed to assess the Elombe (“Champion”) standard operating procedure (SOP), implemented by providers and Mentor Mothers, on HIV-positive pregnant women’s retention between first and second antenatal visits. Sixteen facilities in Kinshasa were randomly assigned to intervention (SOP) or comparison (no SOP). Effect of the SOP was estimated using relative risk. Women in comparison facilities were more likely to miss second visits (RR 2.5, 95% CI 1.05–5.98) than women in intervention facilities (30.0%, n = 27 vs. 12.0%, n = 9, p < 0.002). Findings demonstrate that a simple intervention can reduce critical early loss to care in PMTCT programs providing universal, lifelong treatment.  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