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   925篇
  免费   48篇
耳鼻咽喉   8篇
儿科学   32篇
妇产科学   7篇
基础医学   127篇
口腔科学   3篇
临床医学   149篇
内科学   149篇
皮肤病学   2篇
神经病学   30篇
特种医学   78篇
外科学   48篇
综合类   28篇
预防医学   118篇
眼科学   6篇
药学   57篇
中国医学   1篇
肿瘤学   130篇
  2021年   11篇
  2019年   7篇
  2018年   10篇
  2017年   8篇
  2015年   11篇
  2014年   14篇
  2013年   33篇
  2012年   40篇
  2011年   44篇
  2010年   22篇
  2009年   27篇
  2008年   40篇
  2007年   42篇
  2006年   44篇
  2005年   54篇
  2004年   40篇
  2003年   37篇
  2002年   29篇
  2001年   16篇
  2000年   10篇
  1999年   15篇
  1998年   12篇
  1997年   12篇
  1996年   7篇
  1995年   13篇
  1993年   8篇
  1992年   9篇
  1991年   7篇
  1990年   12篇
  1989年   15篇
  1988年   11篇
  1987年   13篇
  1986年   16篇
  1985年   16篇
  1984年   10篇
  1983年   15篇
  1981年   10篇
  1979年   11篇
  1978年   9篇
  1977年   7篇
  1976年   12篇
  1975年   10篇
  1974年   12篇
  1973年   11篇
  1972年   13篇
  1971年   11篇
  1969年   9篇
  1968年   8篇
  1941年   13篇
  1940年   8篇
排序方式: 共有973条查询结果,搜索用时 15 毫秒
71.
Human lung carcinogenesis is accompanied by complex chromosomal changes that may be detected in interphase cells by fluorescence in situ hybridization (FISH) assay using recently developed multitarget DNA probes. Touch preparations of 20 non-small cell lung carcinomas, sputum specimens from 3 patients with lung cancer and from 11 ex-smokers without lung cancer, and cultured benign bronchial epithelium of 42 high-risk smokers, 9 of whom had concurrent invasive carcinoma, were tested using a four-color FISH probe (LAVysion) targeting centromere 6, 5p15.2, 7p12 (EGFR), and 8q24 (MYC). Significantly high frequencies of abnormal cells were found in each of the 20 NSCLC (100%) and in the 3 sputum specimens from lung cancer patients. None of the cytologically normal sputa contained FISH abnormalities. Cultured bronchial epithelial cells from 11 of 42 patients (26%) were abnormal for at least one probe. Abnormal FISH patterns had no association with gender, presence of tumor or histology. Multicolor FISH can readily detect chromosomal abnormalities in imprints and sputa from lung carcinomas. Chromosomal aneusomy is also frequent in bronchial epithelial cells from long-term smokers. The prognostic significance of the multicolor LAVysion FISH probe set should be validated in a controlled clinical trial.  相似文献   
72.
Hemoglobin Bethesda (beta145 histidine) is one of the two mutants known to affect the penultimate hemoglobin tyrosines. The result of this substitution is extreme disorganization of the oxygenation function of the molecule. Red cells containing 45% Hb Bethesda and 55% Hb A have increased oxygen affinity but, paradoxically, a normal Bohr effect. As is usually seen with other hemoglobins with increased oxygen affinity, Hb Bethesda clinically is manifest in heterozygotes by erythrocytosis. Red cell production in affected individuals is erythropoietin dependent. The reciprocal interdependence of oxygen delivery and effective erythropoiesis was documented by alterations in erythropoietin excretion, quantitative iron kinetics, and reticulocyte production in response to phlebotomy-induced reduction in the oxygen-carrying capacity.  相似文献   
73.
74.
PURPOSE: To explore perceived barriers and benefits to physical activity in people with serious and persistent mental illness (SPMI) who were enrolled in community-based psychiatric rehabilitation. DESIGN AND METHODS: Four focus groups, two for men and two for women, were held with a total of 34 outpatients from two program sites. The investigators used a semistructured interview guide to facilitate the discussions. Audiotapes of the discussions were transcribed and analyzed for concepts and themes. FINDINGS: Significant barriers to physical activity were: mental illness symptoms, medications, weight gain from medications, fear of discrimination, and safety concerns. Being in a psychiatric rehabilitation program offered comfort and belonging, but it also had the effect of leaving activity initiation up to the program staff, which some participants perceived was part of required program compliance. However, participants viewed physical activity positively, and they linked being active to improved mental health. CONCLUSIONS: Outpatients in psychiatric rehabilitation valued physical activity, but mental illness symptoms, medication sedation, weight gain, fear of unsafe conditions, fear of discrimination, and interpretations of program compliance were barriers. Confronting how attitudes and barriers specific to this population can affect activity and reframing program compliance to include the independent initiation of activity as part of improving health might help clients of mental health services to become more active.  相似文献   
75.
This report describes unusual radiologic and pathologic findings in a patient with multiple small bowel metastases from squamous cell carcinoma of the lung. The diagnostic work-up revealed a large, pleural-based, right lung mass, a large left adrenal mass, two ulcerated small bowel masses, and a unique giant peduncular mass that caused intermittent intussusception. A pertinent review of the literature is presented.  相似文献   
76.
77.
Tuberculosis (TB) is a significant health problem for most of the world's populations, and prevalence among indigenous groups is typically higher than among their nonindigenous neighbors. Native South Americans experience high rates of TB, but while research in several other world populations indicates that susceptibility is multifactorial, polygenic, and population-specific, little work has been undertaken to investigate factors involved in Native American susceptibility. We conducted a family-based association study to examine immunologically relevant polymorphisms of a candidate gene, the vitamin D receptor, in conjunction with three measures of TB status in two Native Paraguayan populations, the Aché and the Avá. This is the first large-scale genetic analysis of Native South Americans to examine susceptibility to both infection and disease following exposure to M. tuberculosis. These two types of susceptibility reflect differences in innate and acquired immunity that have proven difficult to elucidate in other populations. Our results indicate that among the Aché, the FokI F allele protects individuals from infection, while the TaqI t allele protects against active disease but not infection. In particular, FF homozygotes are 17 times more likely to test positive for exposure to TB, but no more likely to have ever been diagnosed with active TB. TT individuals are 42 times less likely to mount a delayed-type hypersensitivity response, and the T allele was significantly more likely to have been transmitted to offspring who have been diagnosed with active TB. This ongoing research is of vital importance to indigenous groups of the Americas, because if there is a population-specific component to TB susceptibility, it will likely prove most effective to incorporate this into future treatment and prevention strategies.  相似文献   
78.
Previous research suggests considerable heterogeneity within groups of individuals identified as having low self-awareness or good self-awareness following acquired brain injury (ABI). The present study aimed to identify typologies of individuals according to neuropsychological and psychological factors related to awareness deficits and compare emotional adjustment and psychosocial outcomes at the initial assessment and 12-month follow-up. Eighty-four participants with ABI (mean time since injury = 3.9 years) were assessed on the Self-Awareness of Deficits Interview, Awareness Questionnaire, Symptom Expectancy Checklist, Marlowe-Crowne Social Desirability Scale, Hospital Anxiety Depression Scale, Sydney Psychosocial Reintegration Scale, and an error self-regulation index. A 12-month follow-up assessment of emotional adjustment and psychosocial outcomes was conducted. A hierarchical cluster analysis distinguished four awareness typologies, namely, "poor self-awareness" (n = 12), "high defensiveness" (n = 13), "high symptom reporting" (n = 15), and "good self-awareness" (n = 44). An overall comparison of outcomes indicated that the poor self-awareness and high symptom reporting typologies experienced poorer outcomes than the high defensiveness and good self-awareness typologies. The findings confirm that there are different awareness typologies and highlight the need to tailor interventions according to the nature of awareness deficits.  相似文献   
79.
High‐risk human papillomavirus (hrHPV) testing has become an integral component of cervical cancer screening, given that persistent infection with hrHPV was recognized as a significant risk factor for most precancers and cancers of the cervix. Particularly, testing for hrHPV types (in conjunction with cervical cytology) has been approved for primary screening in women over 30 years of age and for cost‐effective triaging of equivocal cervical cytology results. HPV was a small double‐stranded DNA virus that cannot be cultured in vitro; so, different types of tests have been developed to detect its presence. Various molecular techniques were available for detecting the presence and/or quantity of hrHPV. In this review, the testing options for hrHPV and its surrogates, with an emphasis on those approved by the US Food and Drug Administration (FDA), were detailed. Cancer (Cancer Cytopathol) 2011;. © 2011 American Cancer Society.  相似文献   
80.
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