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   77篇
  免费   3篇
  国内免费   2篇
儿科学   2篇
基础医学   13篇
口腔科学   2篇
临床医学   4篇
内科学   13篇
皮肤病学   2篇
神经病学   2篇
特种医学   8篇
外科学   7篇
综合类   9篇
预防医学   2篇
眼科学   1篇
药学   5篇
中国医学   6篇
肿瘤学   6篇
  2022年   1篇
  2018年   1篇
  2017年   2篇
  2016年   1篇
  2015年   4篇
  2014年   6篇
  2013年   3篇
  2012年   7篇
  2011年   7篇
  2010年   6篇
  2009年   6篇
  2008年   3篇
  2007年   4篇
  2006年   6篇
  2005年   3篇
  2004年   2篇
  2001年   1篇
  1999年   1篇
  1998年   1篇
  1997年   1篇
  1996年   3篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有82条查询结果,搜索用时 15 毫秒
41.
42.
目的:采用HPLC-DAD-ELSD建立石斛指纹图谱,并对金钗、鼓槌、叠鞘、细茎和反瓣等5种石斛的指纹图谱进行对比研究。方法:采用Dikma C18(250 mm×4.6 mm,5μm)色谱柱,流动相为乙腈-0.5%冰乙酸水溶液,梯度洗脱,柱温30℃,流速1 mL·min-1,DAD串联蒸发光散射检测器检测。结果:建立5种石斛的HPLC指纹图谱,并标定9个指纹峰,5种石斛相似度较低。结论:建立的指纹图谱方法稳定、可靠、重现性好,可直接反映石斛品种与化学成分变化的关系。  相似文献   
43.

Background

Maternal mortality in poor countries reflects the under-development in these societies. Global recognition of the burden of maternal mortality and the urgency for a reversal of the trend underpin the Millenium Development Goals (MDGs).

Objective

To determine risk factors for maternal mortality in institutional births in Nigeria.

Method

Twenty one health facilities in three states were selected using stratified multi-stage cluster sampling strategy. Information on all delivered mothers and their newborn infants within a three-month period was culled from medical records.

Results

A total of 9 208 deliveries were recorded. About one-fifth (20.5%) of women had no antenatal care while 79.5% had at least one antenatal visit during pregnancy. Four-fifths (80.5%) of all deliveries were normal deliveries. Elective and emergency caesarean section rates were 3.1% and 11.5% respectively. There were 79 maternal deaths and 8 526 live births, giving a maternal mortality ratio of 927 maternal deaths per 100 000 live births. No antenatal care, parity, level of education, and mode of delivery were significantly associated with maternal mortality. Low maternal education, high parity, emergency caesarean delivery, and high risk patients risk independently predicted maternal mortality.

Conclusion

Meeting goal five of the MDGs remains a major challenge in Nigeria. Multi-sectoral approaches and focused political will are needed to revert the high maternal mortality.  相似文献   
44.
Liu K  Feng X  Ma Z  Luo C  Zhou B  Cao R  Huang L  Miao D  Pang R  He D  Lian X  Chen P 《Virology》2012,432(1):73-80
Porcine reproductive and respiratory syndrome is an important infectious disease of pigs and has a significant harmful effect on the livestock industry, especially in China. PRRSV ORF1b gene encodes primary proteins which play a vital role during PRRSV replication. In this paper, various 12-amino-acid peptides were displayed. These peptides could bind to the polymerase and helicase of PRRSV ORF1b protein, respectively, in which p9 exerted the highest antiviral activity with an IC50 of 56 μM, and the minimum toxicity to cells. It was proved that p9 inhibited PRRSV replication in infected MARC-145 cells in a dose-dependent manner, and the amino acid sequence of HRILMRIR was important for antiviral activity of p9. Also, p9 could bind to the cell membrane and penetrated into cells. These result suggested that p9 might be a potential therapeutic drug for PRRSV infection.  相似文献   
45.
目的观察中药筋脉通对糖尿病大鼠坐骨神经NADPH氧化酶p22-phox亚基表达的影响。方法将STZ诱导的糖尿病大鼠随机分为模型组,维生素C组,筋脉通小、中、大剂量组,并设立正常对照组,连续灌胃16周。检测各组治疗前及治疗后4、8、12、16周的体重、血糖;测定第16周时大鼠机械痛阈值;采用免疫组化法测定大鼠坐骨神经NADPH氧化酶p22-phox亚基的表达,并进行半定量分析。结果与正常组相比,各组糖尿病大鼠体重均显著下降(P〈0.01),血糖均明显升高(P〈0.01);与模型组比较,各治疗组大鼠体重及血糖在各时间点均无显著差异(P〉0.05)。与正常组相比,模型组、Vc组、筋脉通小、大剂量组机械痛阈值显著降低(P〈0.01);各治疗组机械痛阈值较模型组均明最升高(P〈0.01);与VC组比较,筋脉通中剂量组机械痛阈值显著升高(P〈0.01)。与正常组相比,模型组及各治疗组p22亚基的IOD值明显升高(P〈0.05,P〈0.01);各治疗组p22哑基的IOD值较模型组均显著降低(P〈0.01);与VC组比较,筋脉通中、大剂量组p22亚基IOD值显著降低(P〈0.01,P〈0.05)。结论筋脉通能显著降低大鼠坐骨神经NADPH氧化酶p22-phox亚基的表达。  相似文献   
46.

Background

Cost-sharing schemes incorporating modest targeted subsidies have promoted insecticide-treated nets (ITNs) for malaria prevention in the Kilombero Valley, southern Tanzania, since 1996. Here we evaluate resulting changes in bednet coverage and malaria transmission.

Methods

Bednets were sold through local agents at fixed prices representing a 34% subsidy relative to full delivery cost. A further targeted subsidy of 15% was provided to vulnerable groups through discount vouchers delivered through antenatal clinics and regular immunizations. Continuous entomological surveys (2,376 trap nights) were conducted from October 2001 to September 2003 in 25 randomly-selected population clusters of a demographic surveillance system which monitored net coverage.

Results

Mean net usage of 75% (11,982/16,086) across all age groups was achieved but now-obsolete technologies available at the time resulted in low insecticide treatment rates. Malaria transmission remained intense but was substantially reduced: Compared with an exceptionally high historical mean EIR of 1481, even non-users of nets were protected (EIR [fold reduction] = 349 infectious bites per person per year [×4]), while the average resident (244 [×6]), users of typical nets (210 [×7]) and users of insecticidal nets (105 [×14]) enjoyed increasing benefits.

Conclusion

Despite low net treatment levels, community-level protection was equivalent to the personal protection of an ITN. Greater gains for net users and non-users are predicted if more expensive long-lasting ITN technologies can be similarly promoted with correspondingly augmented subsidies. Cost sharing strategies represent an important option for national programmes lacking adequate financing to fully subsidize comprehensive ITN coverage.  相似文献   
47.
Oral Diseases (2010) 16 , 210–216 Objective: The purpose of this study was to investigate the use of saliva for the identification of human cytomegalovirus (HCMV) in allogeneic hematopoietic stem cell transplant patients by real time PCR compared with blood. Materials and methods: Saliva and blood samples were sampled weekly in 30 allogeneic hematopoietic stem cell transplant patients until 100 days after transplant. Total genomic DNA, extracted from saliva and whole‐blood samples, was used for HCMV real time PCR. Nonparametric tests were performed, and P value ≤0.05 was considered statistically significant. Results: Human cytomegalovirus DNA load in saliva showed a high correlation with viral DNA in the blood ( R = 0.858; P < 0.0001). Blood DNA levels also correlated with HCMV antigenemia ( R = 0.773; P < 0.0001). The HCMV levels in saliva ( P = 0.015) and blood ( P = 0.008) showed higher levels at the beginning of antiviral treatment, with clear reduction after this period. Saliva showed earlier HCMV reactivation than blood detected by real time PCR and antigenemia assay in 11 out of 22 subjects. Conclusions: This study shows that the real time PCR test could be useful to identify HCMV DNA in saliva and to monitor patients at risk of cytomegalovirus disease after allogeneic hematopoietic stem cell transplant. However, further studies are necessary to confirm this data.  相似文献   
48.
Langerhans cells can originate in vitro from immature precursors stimulated with granulocyte macrophage-colony-stimulating factor (GM-CSF), tumour necrosis factor (TNF)-alpha and stem cell factor (SCF). We asked whether these cytokines also control the differentiation state of Langerhans cells within the epidermis and upon leaving this tissue. We harvested sheets of human epidermis by controlled dispase hydrolysis of keratomes, cultured them in RPMI and 10% fetal calf serum for 48 h and analysed the sheets and the cells migrated spontaneously into the medium, most of which were Langerhans cells containing Birbeck granules. By flow cytometry, the intensity of CD1a expression was reduced quite evenly among Langerhans cells migrated from sheets within 48 h. The cells in the sheets underwent loss of dendrites, with a significant reduction in the cell perimeter that was prevented by GM-CSF and TNF-alpha together. Either of these cytokines induced expression of CD18 by cells in the sheets and those in the medium. Moreover, TNF-alpha induced expression of CD54 by cells in the medium, but not by those retained in the sheets, whereas human SCF induced, dose dependently, expression of CD54 by cells in the sheets, but not from those in the medium. The proliferation of allogeneic lymphocytes was much higher when stimulating Langerhans cells were harvested from cultures with any cytokine, rather than from cultures without cytokines. We conclude the following: (i) GM-CSF and TNF-alpha help to maintain full differentiation of Langerhans cells within the epidermis; (ii) cytokine influence on Langerhans cells adhesiveness is in part context dependent; and (iii) pretreatment with cytokines influences positively the number or accessory activity of Langerhans cells on lymphocytes during subsequent mixed leucocyte reaction.  相似文献   
49.
50.
The thyroid gland is an endocrine organ composed of stable cells. It is well known that regenerative capacity of the thyroid tissue is minimal. Various degrees of morphologic alterations do occur in chronic lymphocytic thyroiditis (CLT), including Hashimoto's thyroiditis. Eighty-five CLT cases were analyzed for these morphologic alterations. Small, irregular, atrophic or hyperplastic thyroid follicles were seen adjacent to the lymphocytic infiltration. There was nuclear enlargement, loss of nuclear polarity in thyrocytes and intrafollicular thyrocyte proliferation in these follicles. We thought that the morphologic alterations in involved follicles could be due to regenerative hyperplasia with increased proliferative activity and basement membrane abnormalities. To examine this hypothesis we investigated Ki-67 and laminin immunoreactivity in the involved follicles adjacent to lymphocytic infiltration areas. The uninvolved follicles were used as controls. Immunopositivity of Ki-67 in involved follicles was significantly higher than that in uninvolved follicles (2.97% +/- 2.16 versus 0.83% +/- 1.63, P < 0.001). Laminin immunostaining indicated the destruction or irregular distribution of basement membrane in involved follicles. We conclude that the increased cell proliferation activity and basement membrane abnormalities in the follicles with morphologic changes adjacent to CLT occur in conjunction with regenerative hyperplasia.  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