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   866篇
  免费   60篇
  国内免费   1篇
耳鼻咽喉   4篇
儿科学   74篇
妇产科学   7篇
基础医学   105篇
口腔科学   11篇
临床医学   82篇
内科学   238篇
皮肤病学   18篇
神经病学   63篇
特种医学   107篇
外科学   78篇
综合类   11篇
预防医学   35篇
眼科学   1篇
药学   74篇
中国医学   1篇
肿瘤学   18篇
  2023年   6篇
  2022年   4篇
  2020年   6篇
  2019年   10篇
  2018年   18篇
  2017年   14篇
  2016年   13篇
  2015年   22篇
  2014年   18篇
  2013年   41篇
  2012年   36篇
  2011年   33篇
  2010年   47篇
  2009年   25篇
  2008年   36篇
  2007年   25篇
  2006年   36篇
  2005年   20篇
  2004年   16篇
  2003年   20篇
  2002年   19篇
  2001年   18篇
  2000年   18篇
  1999年   21篇
  1998年   28篇
  1997年   33篇
  1996年   30篇
  1995年   33篇
  1994年   25篇
  1993年   37篇
  1992年   10篇
  1991年   15篇
  1990年   17篇
  1989年   21篇
  1988年   19篇
  1987年   18篇
  1986年   21篇
  1985年   15篇
  1984年   6篇
  1983年   5篇
  1982年   7篇
  1981年   15篇
  1980年   6篇
  1979年   6篇
  1978年   6篇
  1977年   7篇
  1976年   12篇
  1975年   4篇
  1914年   2篇
  1913年   1篇
排序方式: 共有927条查询结果,搜索用时 15 毫秒
51.
Obesity, smoking, and conduct problems have all been associated with decrements in brain function. However, their additive and interactive effects have rarely been examined. To address the deficiency, we studied P300a and P300b electroencephalographic potentials in 218 women grouped by the presence versus absence of: (1) a BMI ≥ 30 kg/m2; (2) recent smoking; and (3) ≥ 2 childhood conduct problems. Analyses revealed smaller P300a and P300b amplitudes over the posterior scalp among recent smokers versus nonsmokers. No corresponding group differences were found in P300 latencies or frontal scalp amplitudes. The most interesting analysis result was an interaction between conduct problems and obesity limited to the frontally generated P300a component: its latency was significantly greater in women with both attributes than in those with either or neither attribute. An exploratory ANOVA, substituting the genotype of a GABRA2 SNP for conduct problems, also demonstrated an interaction with obesity affecting P300a latency. It is hypothesized that conduct problems, and a conduct‐problem‐associated GABRA2 genotype, decrease the age‐of‐onset and/or increase the lifetime duration of obesity. As a result, they may potentiate the adverse effects of obesity on frontal white matter and thereby increase P300a latency. Smoking may affect brain function by a different mechanism to reduce posterior scalp P300a and P300b amplitudes while preserving frontal scalp P300a latency and amplitude. (Am J Addict 2010;00:1–10)  相似文献   
52.
Cystic fibrosis is frequently accompanied by a catabolic condition with low body mass index caused by a number of disease complications. Insulin-like growth factor-I (IGF-I) is an anabolic hormone and an important marker of nutritional status, liver function, and linear growth. Available data on IGF-I in cystic fibrosis are sparse and conflicting. From 1990-3, 235 of our 240 patients (114 males, 121 females, median age 16.2 years, ranged 0.1-44.0 years) had IGF-I measured once by radioimmunoassay. IGF-I was significantly reduced compared with a healthy Scandinavian control population: mean (-2 SD to +2 SD) IGF-I SD score was -0.97 (-3.7 to 1.7) in males and -0.67 (-3.2 to 1.9) in females. Height SD score was -0.95 (-3.3 to 1.4) in males and -0.81 (-3.2 to 1.6) in females. In patients who were still in the growth period a significant correlation of IGF-I SD score to height SD score (r = 0.28, p < 0.001) was found. The low IGF-I concentrations may reflect the catabolic state of many patients with cystic fibrosis and play a part in their abnormal growth pattern.  相似文献   
53.
OBJECTIVE: In previous studies, factors related to a history of suicide attempts in persons with alcohol dependence have included sociodemographic variables, a more severe course of alcoholism, additional substance use disorders, and psychiatric comorbidity. This 5-year prospective study evaluated attributes associated with suicide attempts in a group of treatment-seeking persons with alcohol dependence. Psychiatric comorbidity was examined in terms of a distinction between substance-induced and independent psychiatric disorders. METHOD: Semistructured interviews were conducted with 1,237 alcohol-dependent subjects from the Collaborative Study on the Genetics of Alcoholism both at an initial evaluation and at a 5-year follow-up. Clinically relevant information was gathered at baseline, and suicidal behavior, aspects of alcohol dependence, and drug use were evaluated at the follow-up interview. RESULTS: Alcohol-dependent subjects (N=56) with suicide attempts during the follow-up period were more likely than subjects with no suicide attempts (N=1,181) to have made prior attempts. Other factors related to future suicide attempts in univariate analyses included younger age, being separated or divorced, other drug dependence, substance-induced psychiatric disorders, and indicators of a more severe course of alcoholism. Gender did not predict future attempts. CONCLUSIONS: A 5-year prospective evaluation of attributes associated with suicide attempts among alcohol-dependent persons identified factors that contributed to a small but significant proportion of the variance for future suicidal behavior.  相似文献   
54.
Immunological and functional protein S, protein C and antithrombin III levels and anticoagulant responses to activated protein C were measured in 24 patients with stroke in childhood. No hereditary deficiencies were found. The protein S levels in healthy controls of younger age did not differ from the adult levels. For optimal screening of protein S deficiency, measurements using functional as well as immunological assays are recommended. Appropriate criteria for the diagnosis of the deficiencies must be carefully applied if unnecessary anxiety and inappropriate treatment of children are to be avoided.  相似文献   
55.
Three hundred and ninety-six babies born in Sheffield between 1982 and 1990 identified as being at "very high risk" of unexpected infant death by means of a scoring system, received an intensive programme of health care including a case discussion between a paediatrician, the GP and the health visitor held in the family doctor's surgery, weekly visits from the health visitor and informal hospital admission. Significantly fewer sudden unexpected infant deaths occurred in this group than were expected by logistic regression anlysis or occurred in the best available control group with comparable scores ( p = 0.024). Problems in evaluation include identification of an adequate control population, ethical difficulties in introducing a controlled study when the programme is already perceived as effective, and the calculation of "expected death rates". The results of this study indicate that very energetic programmes of intervention may prevent some deaths in vulnerable infants.  相似文献   
56.
Drinking, but not alcohol-dependent, 18-29-year-old daughters of alcoholics (n = 38) from the Collaborative Study on the Genetics of Alcoholism were compared to 75 family-history-positive (FHP) men from the same families, and 68 family-history-negative (FHN) male controls. Subjects received 0.75 ml/kg of ethanol (for women), 0.9 ml/kg of ethanol (for men), and placebo, each of which was consumed over 8 min on different occasions. The breath-alcohol concentrations (BrAC) and reactions to alcohol [using the Subjective High Assessment Scale (SHAS) and body sway measures] were evaluated over 210 min. The results indicate that, despite slightly higher BrAC values for the FHP men, on the SHAS the FHP women and the FHP men demonstrated significantly lower scores than the FHN male controls, although the values for FHP men and women did not differ. On body sway, the FHP men showed evidence of less alcohol-related increases than FHN men, and there was a trend in the same direction for FHP women, but only early in the session (e.g. at 60 min). Pilot data for 11 FHN women revealed higher scores for both SHAS and body sway at 60 min, compared to FHP women, but, perhaps reflecting the small number of subjects, the family history differences were not significant. Overall, the results in FHP women resemble those for FHP men, and suggest that a low level of response to alcohol might also be a characteristic of daughters of alcoholics.  相似文献   
57.
Capusten  BM; Azouz  EM; Rosman  MA 《Radiology》1984,152(3):693-694
Radiographs, computed tomograms, and radionuclide bone scans were obtained preoperatively in three children with fibromatosis involving the bones and soft tissues of the extremities. Two of the children had identical scar-like bone lesions of the proximal tibia, which, to the authors' knowledge, have not been reported before in this disease. The lesions recurred in two children.  相似文献   
58.
59.
60.
Computed tomography of abdominal fatty masses   总被引:2,自引:0,他引:2  
  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