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   2248篇
  免费   124篇
  国内免费   22篇
耳鼻咽喉   5篇
儿科学   159篇
妇产科学   33篇
基础医学   229篇
口腔科学   51篇
临床医学   190篇
内科学   455篇
皮肤病学   48篇
神经病学   79篇
特种医学   565篇
外科学   212篇
综合类   31篇
预防医学   84篇
眼科学   24篇
药学   91篇
中国医学   4篇
肿瘤学   134篇
  2023年   4篇
  2022年   7篇
  2021年   20篇
  2020年   15篇
  2019年   20篇
  2018年   38篇
  2017年   23篇
  2016年   35篇
  2015年   40篇
  2014年   53篇
  2013年   86篇
  2012年   74篇
  2011年   54篇
  2010年   101篇
  2009年   82篇
  2008年   69篇
  2007年   52篇
  2006年   51篇
  2005年   54篇
  2004年   37篇
  2003年   36篇
  2002年   40篇
  2001年   35篇
  2000年   48篇
  1999年   34篇
  1998年   136篇
  1997年   121篇
  1996年   131篇
  1995年   95篇
  1994年   81篇
  1993年   84篇
  1992年   32篇
  1991年   30篇
  1990年   24篇
  1989年   61篇
  1988年   50篇
  1987年   58篇
  1986年   49篇
  1985年   53篇
  1984年   28篇
  1983年   32篇
  1982年   34篇
  1981年   22篇
  1980年   39篇
  1979年   20篇
  1978年   19篇
  1977年   20篇
  1976年   26篇
  1975年   26篇
  1974年   3篇
排序方式: 共有2394条查询结果,搜索用时 15 毫秒
1.
Thyroid diseases are common, and use of levothyroxine is increasing worldwide. We investigated the influence of gender, race and socioeconomic status on the diagnosis and treatment of thyroid disorders using data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multicenter cohort study of civil servants (35-74 years of age) from six Brazilian cities. Diagnosis of thyroid dysfunction was by thyrotropin (TSH), and free thyroxine (FT4) if TSH was altered, and the use of specific medications. Multivariate logistic regression models were constructed using overt hyperthyroidism/hypothyroidism and levothyroxine use as dependent variables and sociodemographic characteristics as independent variables. The frequencies of overt hyper- and hypothyroidism were 0.7 and 7.4%, respectively. Using whites as the reference ethnicity, brown, and black race were protective for overt hypothyroidism (OR=0.76, 95%CI=0.64-0.89, and OR=0.53, 95%CI=0.43-0.67, respectively, and black race was associated with overt hyperthyroidism (OR=1.82, 95%CI=1.06-3.11). Frequency of hypothyroidism treatment was higher in women, browns, highly educated participants and those with high net family incomes. After multivariate adjustment, levothyroxine use was associated with female gender (OR=6.06, 95%CI=3.19-11.49) and high net family income (OR=3.23, 95%CI=1.02-10.23). Frequency of hyperthyroidism treatment was higher in older than in younger individuals. Sociodemographic factors strongly influenced the diagnosis and treatment of thyroid disorders, including the use of levothyroxine.  相似文献   
2.
BACKGROUND: Our aims in the present study were to estimate the influences of pain and urinary symptoms on quality of life, and to determine which of these two variables has the most predictive power with respect to quality of life in young men with chronic prostatitis-like symptoms. METHODS: Chronic prostatitis-like symptoms were measured by the National Institutes of Health-Chronic Prostatitis Symptom Index. Of the 28,841 men aged 20 years who lived in the study community, 18,495 men (a response rate 64.1%) agreed to participate in the study. A total of 1057 men who complained of symptoms indicative of chronic prostatitis were included in the study. The influences of pain and urinary symptoms on quality of life were determined using logistic regression analysis. The receiver operating characteristic (ROC) curve was used to estimate the predictive ability of each of these variables with respect to quality of life. RESULTS: Results from multivariate analysis showed that both pain and urinary symptoms were associated with an increased likelihood of impaired quality of life, although pain contributed more to a reduced quality of life than urinary symptoms. Relative to men who experienced mild pain, men who experienced moderate pain had a 3.9-fold risk of poor quality of life (odds ratio [OR], 3.87; 95% confidence interval [CI], 2.86-5.23; P < 0.001) and those who experienced severe pain had a 15.7-fold risk of reduced quality of life (OR, 15.68; 95% CI, 6.59-37.35; P < 0.001). Moderate urinary symptoms were associated with a 1.4-fold risk of bother (OR, 1.41; 95% CI, 1.01-1.99; P < 0.001) and severe urinary symptoms were associated with 2.4-fold risk (OR, 2.39; 95% CI, 1.37-4.12; P < 0.001), relative to mild urinary symptoms. Comparison of the effects of pain and urinary symptoms showed that pain severity had the most predictive power for bother, quality of life, and quality-of-life impact. The areas under the ROC curves for bother, quality of life, and quality-of-life impact were 71.3%, 69.3% and 72.5%, respectively. CONCLUSION: Urinary symptoms and pain might be associated with an increased likelihood of impaired quality of life in young men with chronic prostatitis-like symptoms. In addition, our findings suggest that pain severity is the most influential variable for determining quality of life in this population.  相似文献   
3.
4.
5.
Evaluation of an on-line patient exposure meter in neuroradiology   总被引:1,自引:0,他引:1  
  相似文献   
6.
Pediatric knee MR imaging: pattern of injuries in the immature skeleton   总被引:3,自引:0,他引:3  
  相似文献   
7.
8.
In six patients with doxorubicin-related cardiotoxicity, the severity of decrease in left ventricle ejection fraction (LVEF) was associated with faster myocardial I-123 MIBG washout rates. In four patients with severely decreased LVEF (range 19% to 28%), the 4-hour washout rate varied from 43% to 56%. In two patients with moderate cardiotoxicity (LVEF 42% and 43%), the washout rates were 37% and 35%, respectively. In contrast, in another patient thought to have initial left ventricular dysfunction (LVEF dropped from 66% to 54%), the myocardial I-123 MIBG retention rate was not reduced (6% washout). Subsequent continuation of chemotherapy in this patient was without complication. Reduced I-123 MIBG uptake in the left ventricle generally correlated with areas with abnormal Fourier amplitude values, but in one of the patients with moderate cardiotoxicity, the I-123 MIBG uptake was not reduced in a region with loss of amplitude, indicating dysfunction but probably no myocardial denervation. Analysis of the regional myocardial retention in patients with cardiotoxicity showed no significant difference in the I-123 MIBG washout rates of both segments with or without loss of amplitude. These data suggest that in spite of a localized loss of ventricular function demonstrated by radionuclide angiocardiography, doxorubicin-related cardiotoxicity appears to be based on a global process of myocardial adrenergic derangement.  相似文献   
9.
10.
Inversion recovery (IR), commonly considered a pulse sequence capable of producing T1-weighted images with excellent display of normal anatomy, is versatile: The null point and peak time provide a useful, succinct summary of the properties of IR and its capacity for producing both T1- and T2-weighted images. Shortening of the inversion time (TI) and creation of a short-TI inversion-recovery (STIR) pulse sequence increases sensitivity to malignancy and other abnormalities by making the effects of prolonged T1 and T2 on signal intensity additive and by nulling the signal from fat. The authors examined over 300 patients with various malignancies and compared STIR images with T1- and T2-weighted images obtained at 0.5 T. In 43 cases, signal-difference-to-noise ratios (SD/Ns) were calculated between tumor, fat, and muscle. In general, STIR images demonstrated tumor as a conspicuously high-intensity area in a background of muted, discernible anatomic detail. The good contrast achieved with STIR sequences between tumor and fat (SD/N = 18.1) and tumor and muscle (SD/N = 12.9) consolidated into a single image the information contained separately on T1- and T2-weighted images, which facilitates efficient detection and localization of malignancy.  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