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   271篇
  免费   12篇
  国内免费   3篇
耳鼻咽喉   2篇
儿科学   7篇
妇产科学   7篇
基础医学   36篇
口腔科学   1篇
临床医学   26篇
内科学   79篇
皮肤病学   27篇
神经病学   24篇
外科学   15篇
综合类   1篇
预防医学   30篇
眼科学   2篇
药学   13篇
肿瘤学   16篇
  2022年   1篇
  2021年   8篇
  2020年   3篇
  2019年   4篇
  2018年   4篇
  2017年   3篇
  2016年   7篇
  2015年   7篇
  2014年   8篇
  2013年   12篇
  2012年   21篇
  2011年   22篇
  2010年   10篇
  2009年   6篇
  2008年   6篇
  2007年   9篇
  2006年   8篇
  2005年   10篇
  2004年   10篇
  2003年   20篇
  2002年   13篇
  2001年   6篇
  2000年   4篇
  1999年   13篇
  1998年   4篇
  1997年   2篇
  1996年   4篇
  1995年   6篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   5篇
  1990年   5篇
  1989年   5篇
  1988年   3篇
  1987年   6篇
  1986年   5篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1982年   2篇
  1981年   3篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1976年   1篇
  1974年   1篇
  1969年   1篇
  1967年   2篇
  1966年   1篇
排序方式: 共有286条查询结果,搜索用时 31 毫秒
51.
Hispanic women (HW) are disproportionately affected by HIV, however, little is known regarding their perceived susceptibility for acquiring HIV (SAHIV). We studied predictive factors for perceiving SAHIV among HW. Participants (88.5%) reported not feeling SAHIV. Women who felt SAHIV, had a significant probability of reporting a higher chance for acquiring HIV from their partner's actions (OR 9.75), and a higher probability of not being tested for HIV (OR 2.05). Educational strategies to increase perception of SAHIV and HIV testing knowledge would be beneficial giving emphasis to women who do not perceive to be at risk from their partner's actions.  相似文献   
52.
BACKGROUND: Videocapillaroscopy (VCP) can be used to explore microcirculatory modifications in skin diseases. Psoriasis shows specific capillary alterations reflecting typical histopathological changes. OBJECTIVE: To compare capillary morphology, distribution and density in psoriasis and seborrheic dermatitis of the scalp for differential diagnosis. METHODS: VCP was performed on histology-confirmed scalp lesions of 30 patients with chronic plaque psoriasis, 30 age- and sex-matched patients with seborrheic dermatitis and 30 healthy subjects. The morphology, mean density per mm(2) and mean diameter of capillary loops was measured. RESULTS: Scalp psoriasis exhibited homogeneously tortuous and dilated capillaries (bushy pattern), with a 73 +/- 17 mum (mean +/- standard deviation) diameter of capillary bushes. In contrast, scalp seborrheic dermatitis presented a multiform pattern, with mildly tortuous capillary loops and isolated dilated capillaries, but a substantial preservation of local microangioarchitecture. Mean diameter of capillary bush was significantly lower (27 +/- 4 microm; p < 0.001) and similar to that of the scalp of healthy subjects (21 +/- 5 microm). Capillary loop density was similar in patients with psoriasis (23 +/- 5/mm(2)) seborrheic dermatitis (24 +/- 2/mm(2)) and healthy scalp skin (24 +/- 3/mm(2)). CONCLUSION: VCP could be a useful noninvasive approach for differentiating between psoriasis and seborrheic dermatitis, especially when the scalp is the only affected site.  相似文献   
53.

Background

Since preterm birth is associated with a constellation of pre-, peri- and post-natal risk factors, we hypothesised that prematurity may continue to impact the development of linguistic abilities even up to the end of the preschool years and beyond, giving rise to an atypical developmental trajectory. The study tested this hypothesis at six years of age, investigating whether language is affected by preterm birth and how different linguistic abilities are interrelated.

Method

Seventy monolingual Italian preterms and 34 age-matched controls were recruited. Linguistic abilities (vocabulary, grammar, and phonological awareness) as well as general cognitive developmental levels were measured.

Results

No general cognitive delay emerged, but less developed abilities in vocabulary, grammar, and phonological awareness were found in preterms compared to fullterms. Moreover, the relations among the different linguistic competences differed across groups.

Conclusions

Our study shows that even without brain damage, preterm birth continues to affect linguistic development up to the end of the preschool years, and probably beyond, highlighting a continuity between pre- and peri-natal life and subsequent development, and pointing to an atypical developmental trajectory in this population compared to fullterms (different rates of development, different strategies employed, and differences in the relationships among linguistic abilities).  相似文献   
54.
Hepatitis D virus and hepatitis B virus nucleic acids were detected by Northern and Southern blot hybridization in the sera and livers of 85 chronic carriers of HBsAg and anti-hepatitis D followed up for a mean of 10 yr. We identified three subsets of patients: 13 with hepatitis D virus and hepatitis B virus viremia, 53 with serum hepatitis D virus RNA, but without hepatitis B virus DNA and 19 negative for both nucleic acids. Genomic and subgenomic forms of hepatitis D virus RNA were detected only in patients with hepatitis D virus and hepatitis B virus viremia. Histological findings and disease activity at admission were comparable in the three groups of patients, but the outcome was significantly worse in patients with active replication of both viruses; two of them died of terminal liver failure and hepatocellular carcinoma developed in two; the remaining patients had an uneventful course. These results suggest that active hepatitis B virus replication represents an important previously unrecognized determinant of severe liver damage in patients with chronic hepatitis D virus infection. Since hepatitis B virus provides the means for hepatitis D virus secretion and release from infected cells, active hepatitis B virus multiplication favoring the spread of hepatitis D virus from cell to cell may increase the pathogenetic potential of the defective agent.  相似文献   
55.
Clinical investigation of Primary Biliary Cirrhosis (PBC) patients showed an elevated frequency of rheumatic disorders, as well as their frequent appearance in asymptomatic PBC. Anticentromere region antibodies in PBC patients were pathognomonic for concomitant complete or incomplete CREST syndrome. These antibodies were only found on the HEp2 cell substrate. The constant finding of immune-complexes (IC) with IgM antibody component suggests that they play a role in the pathogenesis of PBC. No statistically significant correlation was found between the amount and classes of circulating IC, HLA class I antigens and rheumatic disorders during PBC.  相似文献   
56.
The value of administering 25 mg of levosulpiride per os approximately one hour before the sodium fluorescein bolus used in fluorangiography is assessed in order to avoid to the onset of nausea and/or vomiting during and after the test. The study was performed in 35 patients. No nausea and/or vomiting was observed in over 90% of cases treated.  相似文献   
57.
This paper introducesnear-set based segmentation method for extraction and quantification of mucin regions for detecting mucinouscarcinoma (MC which is a sub type of Invasive ductal carcinoma (IDC)). From histology point of view, the presence of mucin is one of the indicators for detection of this carcinoma. In order to detect MC, the proposed method majorly includes pre-processing by colour correction, colour transformation followed by near-set based segmentation and post-processing for delineating only mucin regions from the histological images at 40×. The segmentation step works in two phases such as Learn and Run.In pre-processing step, white balance method is used for colour correction of microscopic images (RGB format). These images are transformed into HSI (Hue, Saturation, and Intensity) colour space and H-plane is extracted in order to get better visual separation of the different histological regions (background, mucin and tissue regions). Thereafter, histogram in H-plane is optimally partitioned to find set representation for each of the regions. In Learn phase, features of typical mucin pixel and unlabeled pixels are learnt in terms of coverage of observed sets in the sample space surrounding the pixel under consideration. On the other hand, in Run phase the unlabeled pixels are clustered as mucin and non-mucin based on its indiscernibilty with ideal mucin, i.e. their feature values differ within a tolerance limit. This experiment is performed for grade-I and grade-II of MC and hence percentage of average segmentation accuracy is achieved within confidence interval of [97.36 97.70] for extracting mucin areas. In addition, computation of percentage of mucin present in a histological image is provided for understanding the alteration of such diagnostic indicator in MC detection.  相似文献   
58.
The number of refugees increased in recent years due to factors worldwide, including violence, wars, political strife, and natural disasters. Refugees who are Hispanic women (RHW) in South Florida are a vulnerable population at risk of acquiring HIV infection. Although studies have shown a relationship between self-efficacy for HIV prevention and behavior changes, none have studied RHW. The purpose of this study was to assess whether predictors suggested by the literature were related to self-efficacy for HIV prevention in a sample of RHW. The study is a secondary analysis that uses baseline data from a randomized controlled experimental study, SEPA. A total of 99 refugee Hispanic women from South Florida, 18–50 years of age, participated in the study. There were two predictors of self-efficacy. HIV knowledge was positively related to self-efficacy, and living with a partner was inversely related to self-efficacy for HIV prevention. Culturally competent sexual health education interventions in this population may impact self-efficacy for HIV prevention.  相似文献   
59.
ObjectivesThe purpose of the current study was to describe the factors associated with Mexican American elders in the Southwestern United States who have spent time in a skilled nursing facility (SNF) compared with those who have not.DesignData were collected on the Mexican American elders who reported an SNF stay within 10 years of baseline.ParticipantsA probability sample of 3050 Mexican American elders from five Southwestern states followed from 1993 to 2005 were examined.MeasuresVariables examined included sociodemographics, language of interview, disabilities with instrumental activities of daily living, activities of daily living, self-reported health, cognitive status, and depression.ResultsA total of 78 (3.9%) of 2020 subjects resided in SNFs. Using univariate analyses, older age, English-language interview, poorer cognitive status, and functional disabilities were independently associated with SNF admissions. Logistic regression analyses controlling for age revealed that SNF patients were older (OR = 1.08, P = .001), had an activities of daily living disability (OR = 4.94, P < .001), scored in the depressed range in the Geriatric Depression Scale (OR = 2.72, P = .001), and were more likely to interview in English (OR = 1.95, P = .042), when compared with community counterparts.ConclusionsMexican American elders who resided in an SNF at some point in the previous 10 years were older, and were more likely to be functionally impaired. They also were more likely to prefer English as their primary language, indicating they were more likely to agree to an SNF stay than their Spanish-speaking counterparts.  相似文献   
60.
Human adenoviruses (HAdV) and JC polyomaviruses (JCPyV) have been proposed as markers of fecal/urine contamination of human origin. An indirect immunofluorescence assay has been developed to quantify infectious human adenoviruses types 2 and 41 and JC polyomaviruses strain Mad-4 in water samples. The immunofluorescence assay was compared with other quantitative techniques used commonly such as plaque assay, tissue culture infectious dose-50 and quantitative PCR (qPCR). The immunofluorescence assays showed to be specific for the detection of infectious viruses, obtaining negative results when UV or heat-inactivated viruses were analyzed. The assays required less time and showed higher sensitivity for the detection of infectious viral particles than other cell culture techniques (1 log10 more) evaluated. River water samples spiked previously with human adenoviruses and raw sewage samples were also analyzed using the proposed immunofluorescence assay as well as by qPCR. The results show quantitations with 2 log10 reduction in the numbers of infectious viruses compared with the number of genome copies detected by qPCR. The immunofluorescence assay developed is fast, sensitive, specific, and a standardizable technique for the quantitation and detection of infectious viruses in water samples.  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