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   373篇
  免费   25篇
  2023年   4篇
  2022年   10篇
  2021年   12篇
  2020年   16篇
  2019年   14篇
  2018年   7篇
  2017年   18篇
  2016年   19篇
  2015年   14篇
  2014年   22篇
  2013年   22篇
  2012年   37篇
  2011年   24篇
  2010年   17篇
  2009年   17篇
  2008年   20篇
  2007年   13篇
  2006年   18篇
  2005年   19篇
  2004年   8篇
  2003年   12篇
  2002年   7篇
  2001年   11篇
  2000年   7篇
  1999年   4篇
  1998年   2篇
  1997年   1篇
  1996年   3篇
  1992年   4篇
  1991年   1篇
  1989年   1篇
  1986年   1篇
  1985年   1篇
  1981年   3篇
  1979年   3篇
  1978年   1篇
  1975年   1篇
  1974年   1篇
  1973年   3篇
排序方式: 共有398条查询结果,搜索用时 15 毫秒
91.
92.
Bone involvement of hydatid disease is uncommon but when encountered, it presents few unique pathological features. The pattern of tissue involvement is largely different from that of visceral hydatid cyst. We describe the case of a 47 year-old man from northern India, a case of systemic hydatidosis including the liver and the right lung, presenting with an abscess like lesion in the left gluteal region with pathological fractures of the left femur. Radiographs and CT-scan images showed extensive invasion of the left hemi-pelvis and left proximal femur. Debridement of the honeycombed ilium yielded hydatid fluid, numerous small cysts and necrotic material. Multiple large devitalized and sequestrated bone pieces were recovered from the bone cavity of the affected ilium. A histopathological study of the bone sequestrums revealed the unique pattern of bone invasion by the characteristic laminated multi-layered cyst walls into areas of least resistance. Bone sequestration has not often been described or demonstrated elaborately in published studies of the past. The bone defects formed after debridement of the ilium and proximal femur were filled with bone cement along with augmentation of the femur using intra-medullary nail. The surgical technique adopted in our case although was not expected to be curative owing to the multi-system disease; it did result in significant functional improvement in the patient.  相似文献   
93.
94.
95.
96.
The present study was designed to develop and compare acyclovir containing nano-vesicular liposomes and niosomes based on cholesterol, soya L-alpha-lecithin and nonionic surfactant, span 20. The effort was made to study in vitro whether acyclovir-loaded nanovesicles could sustain the release of the drug by increasing residence time and thus, acyclovir could reduce its dose-related systemic toxicity. There were good vesicular distributions in both of the niosomes and the liposomes. The obtained vesicles were within 1 microm and about 35% of them were within a size of 100 nm. The percentage of drug loading varied and the niosomal vesicles contained more drug as compared with the liposomes. When the in vitro drug release was compared, it was found that the liposomes released about 90% drug in 150 min whereas the drug release was just 50% from the niosomal vesicles in 200 min. Again, the niosomes showed better stability compared with the liposomes. Thus, niosome could be a better choice for intravenous delivery of acyclovir.  相似文献   
97.

Background  

Neuroblastoma, a frequently occurring solid tumour in children, remains a therapeutic challenge as existing imaging tools are inadequate for proper and accurate diagnosis, resulting in treatment failures. Nanoparticles have recently been introduced to the field of cancer research and promise remarkable improvements in diagnostics, targeting and drug delivery. Among these nanoparticles, quantum dots (QDs) are highly appealing due to their manipulatable surfaces, yielding multifunctional QDs applicable in different biological models. The biocompatibility of these QDs, however, remains questionable.  相似文献   
98.

Background

According to WHO Global Health Estimates, tuberculosis (TB) is among the top ten causes of global mortality and ranks second after cardiovascular disease in most high-burden regions. In this systematic review and meta-analysis, we investigated the role of second-hand smoke (SHS) exposure as a risk factor for TB among children and adults.

Methods and Findings

We performed a systematic literature search of PubMed, Embase, Scopus, Web of Science, and Google Scholar up to August 31, 2014. Our a priori inclusion criteria encompassed only original studies where latent TB infection (LTBI) and active TB disease were diagnosed microbiologically, clinically, histologically, or radiologically. Effect estimates were pooled using fixed- and random-effects models. We identified 18 eligible studies, with 30,757 children and 44,432 adult non-smokers, containing SHS exposure and TB outcome data for inclusion in the meta-analysis. Twelve studies assessed children and eight studies assessed adult non-smokers; two studies assessed both populations. Summary relative risk (RR) of LTBI associated with SHS exposure in children was similar to the overall effect size, with high heterogeneity (pooled RR 1.64, 95% CI 1.00–2.83). Children showed a more than 3-fold increased risk of SHS-associated active TB (pooled RR 3.41, 95% CI 1.81–6.45), which was higher than the risk in adults exposed to SHS (summary RR 1.32, 95% CI 1.04–1.68). Positive and significant exposure–response relationships were observed among children under 5 y (RR 5.88, 95% CI 2.09–16.54), children exposed to SHS through any parent (RR 4.20, 95% CI 1.92–9.20), and children living under the most crowded household conditions (RR 5.53, 95% CI 2.36–12.98). Associations for LTBI and active TB disease remained significant after adjustment for age, biomass fuel (BMF) use, and presence of a TB patient in the household, although the meta-analysis was limited to a subset of studies that adjusted for these variables. There was a loss of association with increased risk of LTBI (but not active TB) after adjustment for socioeconomic status (SES) and study quality. The major limitation of this analysis is the high heterogeneity in outcomes among studies of pediatric cases of LTBI and TB disease.

Conclusions

We found that SHS exposure is associated with an increase in the relative risk of LTBI and active TB after controlling for age, BMF use, and contact with a TB patient, and there was no significant association of SHS exposure with LTBI after adjustment for SES and study quality. Given the high heterogeneity among the primary studies, our analysis may not show sufficient evidence to confirm an association. In addition, considering that the TB burden is highest in countries with increasing SHS exposure, it is important to confirm these results with higher quality studies. Research in this area may have important implications for TB and tobacco control programs, especially for children in settings with high SHS exposure and TB burden.  相似文献   
99.
100.
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