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   2666篇
  免费   253篇
  国内免费   4篇
耳鼻咽喉   28篇
儿科学   126篇
妇产科学   46篇
基础医学   317篇
口腔科学   67篇
临床医学   358篇
内科学   405篇
皮肤病学   42篇
神经病学   314篇
特种医学   88篇
外国民族医学   1篇
外科学   311篇
综合类   21篇
一般理论   3篇
预防医学   441篇
眼科学   29篇
药学   165篇
肿瘤学   161篇
  2024年   11篇
  2023年   34篇
  2022年   68篇
  2021年   166篇
  2020年   121篇
  2019年   157篇
  2018年   148篇
  2017年   112篇
  2016年   119篇
  2015年   141篇
  2014年   127篇
  2013年   183篇
  2012年   270篇
  2011年   216篇
  2010年   107篇
  2009年   101篇
  2008年   149篇
  2007年   109篇
  2006年   114篇
  2005年   88篇
  2004年   65篇
  2003年   62篇
  2002年   30篇
  2001年   16篇
  2000年   15篇
  1999年   12篇
  1998年   9篇
  1997年   7篇
  1996年   6篇
  1995年   4篇
  1994年   7篇
  1993年   10篇
  1992年   10篇
  1991年   8篇
  1990年   10篇
  1989年   12篇
  1988年   6篇
  1987年   4篇
  1986年   6篇
  1985年   8篇
  1984年   3篇
  1983年   6篇
  1982年   3篇
  1981年   3篇
  1978年   3篇
  1977年   5篇
  1973年   3篇
  1971年   5篇
  1967年   7篇
  1869年   3篇
排序方式: 共有2923条查询结果,搜索用时 15 毫秒
1.
Annals of Surgical Oncology - The role of sentinel lymph node biopsy (SLNB) when ductal carcinoma in situ with microinvasion (DCISM) is identified on core biopsy is unclear. Our aim was to assess...  相似文献   
2.
3.
Hepatitis C virus (HCV) infection is a major public-health-care problem, with over 170 million infected worldwide. Patients with chronic HCV infection often complain of various cognitive problems as well as symptoms of depression, anxiety, and fatigue. Relatively little is known, however, about the specific cognitive deficits that are common among HCV patients, and the influence of psychiatric symptomatology on cognitive functioning. In the current study of 21 chronically infected HCV patients, we assessed subjective cognitive dysfunction, depression, anxiety, and fatigue and compared these symptom areas to cognitive tests assessing visuoconstruction, learning, memory, visual attention, psychomotor speed, and mental flexibility. Results revealed that cognitive impairment ranged from 9% of patients on a visuoconstruction task to 38% of patients on a measure of complex attention, visual scanning and tracking, and psychomotor speed, and greater HCV disease severity as indicated by liver fibrosis was associated with greater cognitive dysfunction. Objective cognitive impairment was not related to subjective cognitive complaints or psychiatric symptomatology. These findings suggest that a significant portion of patients with chronic HCV experience cognitive difficulties that may interfere with activities of daily living and quality of life. Future research using cognitive measures with HCV-infected patients may assist researchers in identifying if there is a direct effect of HCV infection on the brain and which patients may be more likely to progress to cirrhosis and hepatic encephalopathy.  相似文献   
4.
Two children with unusual extramedullary common acute lymphoblastic leukemia antigen (CALLA)-positive (CD10) disease are reported. Isolated masseter infiltration with CD10/CD19-positive lymphoblasts was present in both patients with no other evidence of disease. One child had relapse of common acute lymphoblastic leukemia, and the other had primary disease. Disease may have spread from lymph nodes overlying the masseter muscle. Immunophenotyping and immunogenotyping provided a rapid and accurate diagnosis for both children.  相似文献   
5.
Strain UCMJ was isolated from the choana of a jackass penguin (Spheniscus demersus) with recurrent mucocaseous choanal discharge. Isolation of this mycoplasma expands the known range of species hosting mycoplasmas. The name Mycoplasma sphenisci sp. nov. is proposed for this new species, for which strain UCMJ is the type strain.  相似文献   
6.
Screening for toxoplasmosis in pregnancy.   总被引:1,自引:0,他引:1       下载免费PDF全文
The prevalence of antibody against Toxoplasma gondi in a population of 715 pregnant women has been evaluated by two methods: indirect haemagglutination antibody (IHA) and indirect fluorescent antibody (IFA) test and all positive sera were checked by the dye test. Five hundred of the study population were questioned on diet and on animal contact to elucidate a possible relation to the prevalence of antibody. Results are expressed in international units (IU) of antibody against T gondi. Of the 715 sera, 171 were positive by IHA and 173 by IFA. One hundred and sixty-seven sera were positive by both tests, ninety-eight (58%) correlating exactly, as to the concentration of antibody. The ten sera which were not positive by both tests all had detectable antibody at the minimum concentration only (12 IU). The dye test confirmed all sera positive by both tests with the exception of three. It also confirmed one of four sera positive by IHA antibody alone and two of six positive by IFA alone. All sera that proved dye test-negative had low antibody concentrations (12 IU) by IHA or IFA. The IHA test, which is commercially available in kit form, would be suitable for use as a screening test during pregnancy. The estimated annual rate of antibody acquisition over the age range 16-40 years is 1.2% per annum with the highest rate in the 36-40 age group (2.5% per annum) and the lowest in the 26-30 age group (0.4% per annum). The clinical history was not significantly different between those with and those without antibody against T gondi but significantly more women in the 36-40 age group had a history of animal contact than those in the 26-30 age group. No conclusive evidence of recent or current infection was found.  相似文献   
7.
8.
Diabetes insipidus is a well-recognized complication of Langerhans-cell histiocytosis (histiocytosis X), but its frequency and natural history are not well defined. Of 52 children with histiocytosis whom we studied, 12 (23 percent) had diabetes insipidus. Only two children had diabetes insipidus at presentation with histiocytosis, but the cumulative risk that it would develop during the first four years after the presentation and diagnosis of histiocytosis was found to be 42 percent. Diabetes insipidus occurred most often among children with multisystem disease and those with proptosis. To determine the natural history of diabetes insipidus in children with histiocytosis, we measured the response of urinary arginine vasopressin to water deprivation every six months in 21 children who did not have diabetes insipidus and who had had histiocytosis for less than four years. Five of the 21 children (24 percent) had subnormal responses during the initial test. One subsequently had spontaneous improvement in the functioning of the posterior pituitary, and diabetes insipidus subsequently developed in two, as it did in one of the children who initially had normal function of the posterior pituitary. Two of the children received irradiation to the pituitary within two to four weeks after diabetes insipidus developed, but they had no improvement in pituitary function. However, diabetes insipidus improved transiently during prednisolone therapy in one of these children and improved permanently after etoposide therapy in another child. We conclude that prospective study with the use of a simple water-deprivation test will allow partial defects of posterior-pituitary function to be detected in patients with histiocytosis and will permit a more appropriate evaluation of the effects of therapeutic intervention.  相似文献   
9.
Obesity is a modifiable risk factor in breast cancer patients and is predictive of disease outcomes in early-onset breast cancer survivors. The purpose of this review is to summarize the current evidence in the association between early-onset breast cancer and obesity, specifically in African-American women. Reviewing the molecular mechanisms and social determinants of disease in this population can provide a foundation for future interventions in prevention, detection, and treatment aiming at improving outcomes for young breast cancer patients.  相似文献   
10.
BackgroundFor unknown reasons, Hispanic patients with cystic fibrosis (CF) have more severe pulmonary disease than non-Hispanic white patients. In CF, the pulmonary pathogen Pseudomonas aeruginosa is associated with worse outcomes. We sought to determine if Hispanic patients with CF are at an increased risk of acquiring P. aeruginosa or acquire it earlier than non-Hispanic white patients.MethodsThis is a longitudinal study comparing the timing and risk of acquisition of different forms of P. aeruginosa between Hispanic and non-Hispanic white patients aged 0-21 years old with CF in the CF Foundation Patient Registry (CFFPR) in 2008-2013. The age at the initial acquisition of P. aeruginosa (initial acquisition, mucoid, chronic, multidrug-resistant) was summarized using Kaplan-Meier survival curves and analyzed using Cox proportional hazards regression models.ResultsOf 10,464 patients, 788 (7.5%) were Hispanic and 9,676 (92.5%) were non-Hispanic white. Hispanic patients acquired all forms of P. aeruginosa at a younger age than non-Hispanic white patients. Hispanic patients had a higher risk of acquiring P. aeruginosa than non-Hispanic white patients: the hazard ratio (HR) was 1.26 (95% CI 1.16-1.38, p<0.001) for initial P. aeruginosa, 1.59 (95% CI 1.43-1.77, p<0.001) for mucoid P. aeruginosa, 1.91 (95% CI 1.64-2.23, p<0.001) for multidrug-resistant P. aeruginosa, and 1.39 (95% CI 1.25-1.55, p<0.001) for chronic P. aeruginosa.ConclusionsHispanic patients have an increased risk of acquiring P. aeruginosa and acquire it at an earlier age than non-Hispanic white patients in the United States. This may contribute to increased morbidity and mortality in Hispanic patients with CF.  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