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   704篇
  免费   46篇
  国内免费   5篇
耳鼻咽喉   6篇
儿科学   32篇
妇产科学   14篇
基础医学   90篇
口腔科学   23篇
临床医学   57篇
内科学   181篇
皮肤病学   29篇
神经病学   27篇
特种医学   11篇
外科学   137篇
综合类   5篇
预防医学   62篇
眼科学   9篇
药学   41篇
中国医学   5篇
肿瘤学   26篇
  2023年   7篇
  2022年   19篇
  2021年   28篇
  2020年   16篇
  2019年   24篇
  2018年   23篇
  2017年   12篇
  2016年   15篇
  2015年   21篇
  2014年   30篇
  2013年   33篇
  2012年   43篇
  2011年   49篇
  2010年   33篇
  2009年   29篇
  2008年   50篇
  2007年   53篇
  2006年   45篇
  2005年   39篇
  2004年   49篇
  2003年   26篇
  2002年   36篇
  2001年   4篇
  2000年   4篇
  1999年   8篇
  1998年   6篇
  1997年   5篇
  1995年   2篇
  1993年   2篇
  1991年   2篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1979年   3篇
  1976年   3篇
  1975年   5篇
  1974年   1篇
  1973年   3篇
  1972年   3篇
  1971年   2篇
  1970年   1篇
  1969年   1篇
  1968年   2篇
  1967年   1篇
  1962年   1篇
  1923年   1篇
排序方式: 共有755条查询结果,搜索用时 15 毫秒
91.
92.
OBJECTIVE: To determine the seroprevalence of syphilis in pregnant women. METHODS: A seroepidemiologic survey was conducted in 1857 women giving birth at a general hospital in the city of San Luis Potosi, Mexico. RESULTS: Five women (0.27%) were diagnosed with syphilis at the time of delivery. Maternal factors associated with a greater likelihood of syphilis included older age, a higher number of pregnancies and living out of wedlock. CONCLUSIONS: The number of new bhorns exposed to syphilis during pregnancy in San Luis Potosi is underestimated. The results of this study support the need to identify syphilis in infected mothers at the time of delivery.  相似文献   
93.
Despite having achieved an average life expectancy of 75 years, much the same as that of more developed countries, Mexico entered the 21st century with a health system marred by its failure to offer financial protection in health to more than half of its citizens; this was both a result and a cause of the social inequalities that have marked the development process in Mexico. Several structural limitations have hampered performance and limited the progress of the health system. Conscious that the lack of financial protection was the major bottleneck, Mexico has embarked on a structural reform to improve health system performance by establishing the System of Social Protection in Health (SSPH), which has introduced new financial rules and incentives. The main innovation of the reform has been the Seguro Popular (Popular Health Insurance), the insurance-based component of the SSPH, aimed at funding health care for all those families, most of them poor, who had been previously excluded from social health insurance. The reform has allowed for a substantial increase in public investment in health while realigning incentives towards better technical and interpersonal quality. This paper describes the main features and initial results of the Mexican reform effort, and derives lessons for other countries considering health-system transformations under similarly challenging circumstances.  相似文献   
94.
95.

Ethnopharmacological relevance

Agastache mexicana subspecies mexicana (Amm) and xolocotziana (Amx) are used in Mexican traditional medicine to relief cultural affiliation syndromes known as “susto” or “espanto”, for “nervous” condition, and as a sleep aid. Despite its intensive use, neuropharmacological studies are scarce, and the chemical composition of the aqueous extracts has not been described. Aims of the study are: (1) To analyze the chemical composition of aqueous extracts from aerial parts of Amm and Amx. (2) To evaluate the anxiolytic-like, sedative, antidepressant-like effects. (3) Analyze the general toxic effects of different doses.

Materials and methods

Anxiolytic-like and sedative effects were measured in the avoidance exploratory behavior, burying behavior and the hole-board tests. The antidepressant-like actions were studied in the forced swimming and tail suspension tests. Finally, general activity and motor coordination disturbances were evaluated in the open field, inverted screen and rota-rod tests. The acute toxicity of Amm and Amx was determined by calculating their LD50 (mean lethal dose). The chemical analyses were performed employing chromatographic, photometric and HPLC–ESI-MS techniques.

Results

Low doses of Amm and Amx (0.1σ1.0 mg/kg) induced anxiolytic-like actions; while higher doses (over 10 mg/kg) induced sedation and reduced the locomotor activity, exerting a general inhibition in the central nervous system (CNS).

Conclusions

Results support the use of Amm and Amx in traditional medicine as tranquilizers and sleep inducers. Additionally, this paper contributes to the knowledge of the chemical composition of the aqueous extracts of these plants.  相似文献   
96.

Background

Studies reporting on resilience (capacity to overcome life adversity) and the menopausal transition are scarce.

Objective

To assess resilience and related factors in mid-aged Ecuadorian women.

Method

This was a cross sectional study in which 904 women aged 40–59 completed the 14-item Wagnild and Young Resilience Scale (WYRS) and a general socio-demographic questionnaire containing personal and partner data. Lower total WYRS scores indicate less resilience. Internal consistency of the tool was also assessed.

Results

Median age of all surveyed women was 49 years. A 51.1% were postmenopausal, 43.8% lived high altitude, 43.5% were abdominally obese, 12.6% used hormone therapy and 80.8% had a partner. Internal consistency was high for the WYRS tool (Cronbach's alpha: 0.94). Multiple linear regression analysis determined that lower total WYRS scores (less resilience) correlated with high altitude residency, more severe hot flushes, sedentarism, higher abdominal circumferences and having a partner with erectile dysfunction. Contrary to this, higher WYRS scores correlated with higher parity and sexual activity.

Conclusion

As assessed with the WYRS tool, lower resilience of this mid-aged Ecuadorian female sample was related to various female and partner lifestyle and health issues, not necessarily related per se to the ageing process. More research using the tool is warranted.  相似文献   
97.
The ultimate goal of vector vaccines is the control of vector infestations while reducing pathogen infection and transmission to protect against the many diseases caused by vector-borne pathogens. Previously (Vaccine 2011;29:2248-2254), we demonstrated that subolesin vaccination and release of tick larvae after subolesin knockdown by RNA interference (RNAi) were effective for the control of cattle tick, Rhipicephalus (Boophilus) microplus infestations in cattle. In this study, we used the fact that these animals were naturally infected with Anaplasma marginale and Babesia bigemina to evaluate the effect of subolesin vaccination and gene knockdown on tick infection by these cattle tick-transmitted pathogens. Ticks fed on vaccinated cattle had lower subolesin mRNA levels when compared to controls, resembling RNAi results. A. marginale and B. bigemina infection was determined by PCR and decreased by 98% and 99%, respectively in ticks fed on vaccinated cattle and by 97% and 99%, respectively after subolesin knockdown. These results demonstrated that targeting subolesin expression by vaccination or RNAi results in lower subolesin mRNA and pathogen infection levels, probably due to the effect of subolesin downregulation on tick feeding, gene expression and gut and salivary glands tissue development and function. These results suggested that subolesin vaccines could be used for the dual control of tick infestations and pathogen infection, a result that could be relevant for other vectors and vector-borne pathogens.  相似文献   
98.
99.
100.
IntroductionLarge variability among Alzheimer's disease (AD) cases might impact genetic discoveries and complicate dissection of underlying biological pathways.MethodsGenome Research at Fundacio ACE ([email protected]) is a genome-wide study of dementia and its clinical endophenotypes, defined based on AD's clinical certainty and vascular burden. We assessed the impact of known AD loci across endophenotypes to generate loci categories. We incorporated gene coexpression data and conducted pathway analysis per category. Finally, to evaluate the effect of heterogeneity in genetic studies, [email protected] series were meta-analyzed with additional genome-wide association study data sets.ResultsWe classified known AD loci into three categories, which might reflect the disease clinical heterogeneity. Vascular processes were only detected as a causal mechanism in probable AD. The meta-analysis strategy revealed the ANKRD31-rs4704171 and NDUFAF6-rs10098778 and confirmed SCIMP-rs7225151 and CD33-rs3865444.DiscussionThe regulation of vasculature is a prominent causal component of probable AD. [email protected] meta-analysis revealed novel AD genetic signals, strongly driven by the presence of clinical heterogeneity in the AD series.  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