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   1349篇
  免费   90篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   42篇
妇产科学   55篇
基础医学   156篇
口腔科学   17篇
临床医学   100篇
内科学   341篇
皮肤病学   60篇
神经病学   60篇
特种医学   25篇
外科学   208篇
综合类   7篇
预防医学   92篇
眼科学   30篇
药学   122篇
中国医学   18篇
肿瘤学   103篇
  2023年   13篇
  2022年   10篇
  2021年   38篇
  2020年   23篇
  2019年   58篇
  2018年   53篇
  2017年   36篇
  2016年   30篇
  2015年   35篇
  2014年   43篇
  2013年   54篇
  2012年   84篇
  2011年   94篇
  2010年   58篇
  2009年   43篇
  2008年   88篇
  2007年   71篇
  2006年   74篇
  2005年   62篇
  2004年   69篇
  2003年   52篇
  2002年   49篇
  2001年   42篇
  2000年   52篇
  1999年   30篇
  1998年   9篇
  1997年   10篇
  1996年   10篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1992年   19篇
  1991年   18篇
  1990年   15篇
  1989年   11篇
  1988年   11篇
  1987年   7篇
  1986年   9篇
  1985年   5篇
  1984年   2篇
  1983年   6篇
  1982年   6篇
  1981年   2篇
  1980年   2篇
  1978年   2篇
  1975年   2篇
  1974年   3篇
  1970年   2篇
  1969年   6篇
  1968年   3篇
排序方式: 共有1442条查询结果,搜索用时 15 毫秒
1.
2.
A 65-year-old man developed acute limb ischemia, severe abdominal wall and lower limb livedo reticularis following a coronary angiogram. The differential diagnoses of acute limb ischemia and multiple cholesterol emboli syndrome (MCES) are discussed. This work was performed at Long Island Jewish Medical Center, 270-05, 76th Avenue, New Hyde Park, NY 11040.  相似文献   
3.
4.
5.
6.
BACKGROUND: Use of the emergency department (ED) for asthma care is a costly form of health care that is largely preventable. However, little is known about how to reduce the number of people using the ED for asthma care. OBJECTIVE: To identify modifiable factors related to ED visits for asthma among a diverse nonelderly adult population. METHODS: This study used cross-sectional data from the 2001 California Health Interview Survey. A total of 4,359 adult respondents ages 18 to 64 years who reported being diagnosed as having asthma and experiencing symptoms in the past year were included. Any ED visits due to asthma in the previous 12 months among all nonelderly respondents with asthma, with stratification by those with daily or weekly symptoms and with less frequent symptoms, were examined. RESULTS: Adults with daily or weekly asthma symptoms, with fair or poor health status, and who delayed care for asthma because of cost or insurance issues were more likely to visit the ED for asthma. Stratification of the study population into those with daily or weekly symptoms and those with less frequent symptoms revealed that delay in care due to cost or insurance issues and fair or poor health status remained significant for both groups. Latinos and women were more likely to visit the ED in the severe asthma group, whereas Asian, African American, and uninsured adults were more likely to visit the ED in the group with less severe asthma. CONCLUSIONS: Results suggest that to prevent ED visits for asthma, it is important to control asthma symptoms. However, it is equally if not more important to reduce delays in receiving asthma care.  相似文献   
7.
The goal of this study was to determine whether sequence analysis of internal transcribed spacer/5.8S ribosomal DNA (rDNA) can be used to detect fungal pathogens in patients with ocular infections (endophthalmitis and keratitis). Internal transcribed spacer 1 (ITS1) and ITS2 and 5.8S rDNA were amplified by PCR and seminested PCR to detect fungal DNA. Fifty strains of 12 fungal species (yeasts and molds) were used to test the selected primers and conditions of the PCR. PCR and seminested PCR of this region were carried out to evaluate the sensitivity and specificity of the method. It proved possible to amplify the ITS2/5.8S region of all the fungal strains by this PCR method. All negative controls (human and bacterial DNA) were PCR negative. The sensitivity of the seminested PCR amplification reaction by DNA dilutions was 1 organism per PCR, and the sensitivity by cell dilutions was fewer than 10 organisms per PCR. Intraocular sampling or corneal scraping was undertaken for all patients with suspected infectious endophthalmitis or keratitis (nonherpetic), respectively, between November 1999 and February 2001. PCRs were subsequently performed with 11 ocular samples. The amplified DNA was sequenced, and aligned against sequences in GenBank at the National Institutes of Health. The results were PCR positive for fungal primers for three corneal scrapings, one aqueous sample, and one vitreous sample; one of them was negative by culture. Molecular fungal identification was successful in all cases. Bacterial detection by PCR was positive for three aqueous samples and one vitreous sample; one of these was negative by culture. Amplification of ITS2/5.8S rDNA and molecular typing shows potential as a rapid technique for identifying fungi in ocular samples.  相似文献   
8.
Micronuclei and other biomarkers were evaluated in oral cells from 11- to 16-year-old girls living in a foster home in the central area of México City. Variables analyzed for possible association with these biomarkers include smoking habits, body mass index, metabolic polymorphisms for NAT1 and GSTM1 and whether the cells were obtained from the cheek or pharynx. The results indicated that individuals having the NAT1*10 homozygous genotype showed a significant increase in chromatin buds and binucleated cells. When the damage in the cheek was compared with damage in the pharynx, a significant increase in micronuclei and binucleated cells was found for the latter tissue in all the individuals analyzed.  相似文献   
9.
10.
Vasoactive intestinal peptide (VIP), a neuropeptide that is produced by lymphoid as well as neural cells, exerts a wide spectrum of immunological functions, controlling the homeostasis of the immune system through different receptors expressed in various immunocompetent cells. In the last decade, VIP has been clearly identified as a potent anti-inflammatory factor, which acts by regulating the production of both anti- and pro-inflammatory mediators. In this sense, VIP has been described to prevent death by septic shock, an acute inflammatory disease with a high mortality. In addition, VIP regulates the expression of co-stimulatory molecules, this being an action that may be related to modulating the shift toward Th1 and Th2 differentiation. We have recently reported that VIP prevents the deleterious effects of an experimental model of rheumatoid arthritis, by downregulating both inflammatory and autoimmune components of the disease. Therefore, VIP has been proposed as a promising candidate alternative treatment for acute and chronic inflammatory and autoimmune diseases such as septic shock, arthritis, multiple sclerosis, Crohn disease, or autoimmune diabetes.  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