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   515篇
  免费   22篇
耳鼻咽喉   3篇
儿科学   10篇
妇产科学   5篇
基础医学   99篇
口腔科学   12篇
临床医学   27篇
内科学   167篇
皮肤病学   6篇
神经病学   16篇
特种医学   6篇
外科学   50篇
综合类   2篇
预防医学   64篇
眼科学   17篇
药学   19篇
中国医学   8篇
肿瘤学   26篇
  2023年   3篇
  2022年   10篇
  2021年   17篇
  2020年   8篇
  2019年   15篇
  2018年   12篇
  2017年   10篇
  2016年   8篇
  2015年   13篇
  2014年   12篇
  2013年   32篇
  2012年   32篇
  2011年   43篇
  2010年   28篇
  2009年   26篇
  2008年   23篇
  2007年   22篇
  2006年   27篇
  2005年   30篇
  2004年   19篇
  2003年   18篇
  2002年   17篇
  2001年   21篇
  2000年   17篇
  1999年   13篇
  1998年   5篇
  1997年   4篇
  1996年   2篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   7篇
  1991年   4篇
  1990年   2篇
  1989年   7篇
  1988年   4篇
  1987年   4篇
  1986年   2篇
  1985年   5篇
  1984年   3篇
  1983年   1篇
  1982年   2篇
  1979年   2篇
  1975年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有537条查询结果,搜索用时 0 毫秒
81.
Resistance to chloroquine has been linked to polymorphisms within the pfcrt gene of the human malarial parasite Plasmodium falciparum. Here, we have investigated the prevalence of the pfcrt allele associated with chloroquine resistance in the peripheral blood and the placenta of pregnant women diagnosed with a P. falciparum infection. Our molecular epidemiological data show an unequal distribution with a significant under-representation of parasites carrying the mutated pfcrt allele in the placenta, as compared to the peripheral blood. In comparison, no differences were seen with regard to pfmdr1 polymorphisms of these parasites. Our data suggest a selective disadvantage of the polymorphic and a selective advantage of the wild-type pfcrt haplotype in the placenta, supporting the model that the human host provides various microenvironments that favor genetically distinct P. falciparum populations.  相似文献   
82.
Coffin–Siris syndrome or “fifth digit” syndrome is a multiple congenital anomaly-mental retardation syndrome with severe developmental delay, coarse facial features, hirsutism and absent fifth fingernails or toenails or fifth distal phalanges. The etiology of this syndrome remains uncertain. Here we report a stillborn male baby born from consanguineous parents who might represent a very severe form of Coffin–Siris syndrome with cardiac defect and multiple brain malformations including corpus callosum agenesis and Dandy Walker malformation. To the best of our knowledge, it is the first case leading to intrauterine death. Karyotype and array comparative genomic hybridization were normal; these results give additional support to mendelian inheritance for this syndrome. In our family, the most likely mode of inheritance is autosomal recessive and the recurrence is probably as high as 25%.  相似文献   
83.
84.
85.
86.
Although artemisinin resistance has yet to be reported in Africa, surveillance of the efficacy of artemisinin-based combination therapies (ACTs) is warranted. Here, the efficacy of artesunate + sulfadoxine–pyrimethamine (AS+SP) and artemether–lumefantrine (AL) was evaluated in Mali. Randomized open-label comparative in vivo assay of AS+SP versus AL were carried out using the 28-day follow-up World Health Organization protocol. Patients with uncomplicated falciparum malaria and at least 6 months of age were recruited between October 2010 and January 2014. A subset of these patients was selected to measure Plasmodium falciparum clearance time. Polymerase chain reaction-corrected adequate clinical and parasitological responses were 100% for AS+SP and 98.2% for AL with no significant difference (P = 0.06). The reinfection rates were comparable (P = 0.63) with 8.0% for AS+SP and 12.6% for AL. Individuals under 8 years were more susceptible to treatment failure (relative risk = 1.9; 95% confidence interval = 1.2, 3.3). Median parasite clearance half-life was 1.7 hours (interquartile range [IQR] = 1.3–2.2) for AS+SP and 1.9 hours (IQR = 1.5–2.5) for AL with no statistically significant difference (P = 0.24). Efficacy of AS+SP and AL was high. This study provides baseline information on parasite clearance half-lives after ACT treatment, particularly AS+SP, in Mali.  相似文献   
87.

Objective

To investigate the frequency of catastrophic expenditures for emergency obstetric care, explore its risk factors, and assess the effect of these expenditures on households in the Kayes region, Mali.

Methods

Data on 484 obstetric emergencies (242 deaths and 242 near-misses) were collected in 2008–2011. Catastrophic expenditure for emergency obstetric care was assessed at different thresholds and its associated factors were explored through logistic regression. A survey was subsequently administered in a nested sample of 56 households to determine how the catastrophic expenditure had affected them.

Findings

Despite the fee exemption policy for Caesareans and the maternity referral-system, designed to reduce the financial burden of emergency obstetric care, average expenses were 152 United States dollars (equivalent to 71 535 Communauté Financière Africaine francs) and 20.7 to 53.5% of households incurred catastrophic expenditures. High expenditure for emergency obstetric care forced 44.6% of the households to reduce their food consumption and 23.2% were still indebted 10 months to two and a half years later. Living in remote rural areas was associated with the risk of catastrophic spending, which shows the referral system’s inability to eliminate financial obstacles for remote households. Women who underwent Caesareans continued to incur catastrophic expenses, especially when prescribed drugs not included in the government-provided Caesarean kits.

Conclusion

The poor accessibility and affordability of emergency obstetric care has consequences beyond maternal deaths. Providing drugs free of charge and moving to a more sustainable, nationally-funded referral system would reduce catastrophic expenses for households during obstetric emergencies.  相似文献   
88.
BACKGROUND: The residual risk of human immunodeficiency virus (HIV) transmission from blood products in the Abidjan National Blood Transfusion Center was estimated to be 1 in 5780 blood donations over the period 2002 through 2004. We aimed at describing risk behaviors in blood donors who seroconverted for HIV in Abidjan to improve the pre–blood donation selection. STUDY DESIGN AND METHODS: We investigated the behavioral profile of HIV seroconverters assessed before their HIV diagnosis, during the blood donation selection at the blood bank of Abidjan, and compared it to the profile documented after this HIV diagnosis, at enrollment in the PRIMO‐CI cohort. Since 1997, enrollment in this cohort is offered to every blood donor whose delay since HIV seroconversion was 36 months or less. RESULTS: Among the 418 blood donors who seroconverted for HIV between 1997 and 2005, 241 were enrolled in the cohort. Median age was 28 years and 63% were men. The median time between the last HIV‐negative test and the first positive test was 7 months. Since the last blood donation, 29% of donors reported unprotected sexual intercourse with multiple casual sexual partners, 55% unprotected sexual intercourse with one casual sexual partner, and 36% sharing of nail clippers. During the pre–blood donation questionnaire, 69% of HIV seroconverters had reported unprotected sexual intercourse since the last blood donation (vs. 89% reported after donation), and 7% had had multiple casual sexual partners (vs. 32%). CONCLUSION: Volunteer blood donors who seroconverted for HIV in Abidjan reported a high proportion of unprotected sexual intercourse with casual sexual partners.  相似文献   
89.
Stercoral perforation of the colon is rare and usually occurs in elderly patient suffering from chronic constipation. It can also occur in younger patient. The authors report on the case of a 42-year-old patient who presented to emergency department with acute abdomen. Initial resuscitation was performed and the patient underwent urgent laparotomy. He was found to have a massive fecal impaction which extended from the rectum to right flexure of the colon and resulted primarily in feculent peritonitis, which lead to a double perforation of the sigmoid colon and the transverse colon, and secondarily in a volvulus of the sigmoid colon. The patient underwent left hemicolectomy with Hartmann colostomy. He died two days after surgery. The size of the fecaloma together with the double perforation and the volvulus of the sigmoid colon make the interest in this case, which is never reported in the literature, at least to our knowledge.  相似文献   
90.
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