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   11636篇
  免费   650篇
  国内免费   129篇
耳鼻咽喉   186篇
儿科学   171篇
妇产科学   246篇
基础医学   1745篇
口腔科学   261篇
临床医学   1004篇
内科学   2094篇
皮肤病学   563篇
神经病学   671篇
特种医学   857篇
外科学   1827篇
综合类   74篇
一般理论   1篇
预防医学   625篇
眼科学   183篇
药学   954篇
中国医学   156篇
肿瘤学   797篇
  2023年   63篇
  2022年   233篇
  2021年   361篇
  2020年   178篇
  2019年   278篇
  2018年   299篇
  2017年   218篇
  2016年   355篇
  2015年   487篇
  2014年   598篇
  2013年   699篇
  2012年   985篇
  2011年   965篇
  2010年   607篇
  2009年   496篇
  2008年   668篇
  2007年   616篇
  2006年   558篇
  2005年   567篇
  2004年   425篇
  2003年   378篇
  2002年   341篇
  2001年   226篇
  2000年   238篇
  1999年   187篇
  1998年   106篇
  1997年   84篇
  1996年   80篇
  1995年   68篇
  1994年   52篇
  1993年   51篇
  1992年   64篇
  1991年   57篇
  1990年   58篇
  1989年   62篇
  1988年   69篇
  1987年   52篇
  1986年   52篇
  1985年   61篇
  1984年   48篇
  1983年   56篇
  1982年   33篇
  1981年   28篇
  1980年   32篇
  1979年   30篇
  1978年   35篇
  1977年   32篇
  1976年   26篇
  1974年   17篇
  1973年   24篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
31.
32.
BackgroundUreaplasma parvum (UP) is commonly isolated in the genitor-urinary tract and may cause various clinical features, including microscopic hematuria (MH). Some UP serovars are more commonly related with specific urogenital disease, but the evidences have been conflicting. This study primarily aimed to research the possible associations between specific UP serotypes and genito-urinary pathogenicity in female patients showing MH with/without chronic micturition urethral pain (CMP).MethodsThis study retrospectively reviewed 276 female patients having MH with/without CMP, who visited health screening center or female infertility clinic. All patients underwent multiplex polymerase chain reaction (PCR) tests with vaginal and urine samples to evaluate the infection rate and serotypes of UP. The antimicrobial susceptibility of UP and the predictors of CMP among UP infected patients were also analyzed. All patients were followed up at least for 6-months.ResultsForty-nine patients (17.8%) showed urinary UP infection. Urinary UP serotyping showed the prevalence of seorvar-1, -3, -6 and -14 were 24.5%, 30.6%, 18.4% and 26.5%, respectively. 79.6% of the urinary UP positive patients accompanied vaginal UP infection. 22 patients of the cohort (8.0%) had CMP whereas serovars-3 and -14 accompanied CMP in 54.5% and 41.0% cases, respectively. No serovars-6 infection case had CMP. 26.4% of the cohort were infertile whereas 10.9% of these infertile patients were positive for urinary tract infection with UP serotype-3 or -14. Doxycycline, josamycin and pristinamycin were the most active antibiotics with the lowest rate of resistance (0.0%) for treating UP. At 1-month post-initial treatment with doxycycline, all UP serotypes were eradicated and no patient complained of urethral discomfort. However, simultaneous urinary and vaginal reinfection of serovar-3 (5 cases) and serovar-5 (1 case) were confirmed at 3-months post-initial doxycycline therapy. The logistic regression analyses revealed that serovars-3 [hazard ratio (HR) 1.354, P value 0.018] and -14 (HR 1.103, P value 0.046) were significantly associated with CMP in female patients having MH.ConclusionsUP serovars-3 and -14 infections could be associated with CMP in female patients having MH. Doxycycline, josamycin and pristinamycin were effective for treating UP. Serovar-3 showed higher reinfection rate than other serotypes after antibiotics treatment.  相似文献   
33.
34.
35.
36.
OBJECTIVES: To clarify the clinical significance of increased signal intensities on T1 weighted magnetic resonance imaging (MRI) we performed a large-scale epidemiological study on asymptomatic manganese (Mn)-exposed workers with its focus on MRI. METHODS: We randomly selected 121 male workers out of a total of 750 workers including Mn-exposed, non-exposed manual, and non-exposed clerical workers in the factories. We studied environmental and biological monitoring, neurological examination, and MRI. RESULTS: The proportion of workers with increased signal intensities among the exposed, the non-exposed manual workers, and the non-exposed clerical workers was 46.1%, 18.8%, and 0%, respectively. Especially, 73.5% of the welders showed increased signal intensities. In no subject, were clinical signs of manganism observed. The pallidal index correlated with blood Mn concentration. CONCLUSION: Increase in signal intensities on the T1-weighted image reflect recent exposure to Mn, but not necessarily manganism. At which increase of signal intensity, the progression of manganism from Mn exposure occurs, remains to be solved.  相似文献   
37.
J. Moon  R. M du Bois  T. Colby  D. Hansell    A. Nicholson 《Thorax》1999,54(11):1009-1014
BACKGROUND: Respiratory bronchiolitis-associated interstitial lung disease (RBILD) is a rare form of interstitial lung disease which may present in similar fashion to other types of chronic interstitial pneumonia. The purpose of this study was to undertake a clinicopathological review of 10 patients with RBILD and to examine the clinical and imaging data related to its histopathological pattern, in particular the relationship of RBILD to smoking. METHODS: Thirteen out of 168 retrospectively reviewed patients, from whom biopsy specimens were taken for suspected diffuse lung disease, were identified with a histopathological pattern of RBILD. Three cases were rejected as follow up data were unavailable. The 10 remaining cases constituted the study group and both clinical and imaging data were collected from patients' notes and referring physicians. RESULTS: Histopathologically, four cases of RBILD overlapped with the pattern of desquamative interstitial pneumonitis (DIP) and nine also had microscopic evidence of centrilobular emphysema. Nine patients were smokers, ranging from 3 to 80 pack years. The one non-smoker had an occupational exposure to the fumes of solder flux. The sex distribution was equal with an age range of 32-65 years. Two patients were clubbed. Lung function tests showed both restrictive and obstructive patterns together with severe reductions in carbon monoxide transfer factor in seven patients. Chest radiographs showed reticular or reticulonodular infiltrates in five patients and a ground glass pattern in two. CT scans were consistent with either DIP or RBILD in six of eight patients. Although seven patients remained stable or improved, either with or without treatment, three patients deteriorated. CONCLUSIONS: This study adds weight to the hypothesis that smoking can cause clinically significant interstitial lung disease, with deterioration in pulmonary function despite treatment. Given the overlapping histopathological patterns of RBILD and DIP and their strong association with smoking, the term "smoking related interstitial lung disease" is suggested for those patients who are smokers.  相似文献   
38.
39.
40.
Activity-guided fractionation of the roots of Anthriscus sylvestris resulted in the isolation and characterization of five cytotoxic compounds, deoxypodophyllotoxin (1), falcarindiol (2), and angeloyl podophyllotoxin (5) from the hexane soluble fraction and morelensin (3), bursehernin (4) from the chloroform soluble fraction. It is the first report of the occurrence of compound 5 in nature.  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