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   1020篇
  免费   74篇
  国内免费   3篇
耳鼻咽喉   11篇
儿科学   51篇
妇产科学   34篇
基础医学   66篇
口腔科学   40篇
临床医学   73篇
内科学   264篇
皮肤病学   1篇
神经病学   136篇
特种医学   21篇
外科学   124篇
综合类   5篇
一般理论   1篇
预防医学   54篇
眼科学   5篇
药学   39篇
中国医学   1篇
肿瘤学   171篇
  2021年   11篇
  2020年   15篇
  2019年   21篇
  2018年   21篇
  2017年   18篇
  2016年   19篇
  2015年   30篇
  2014年   22篇
  2013年   44篇
  2012年   53篇
  2011年   52篇
  2010年   35篇
  2009年   39篇
  2008年   44篇
  2007年   54篇
  2006年   64篇
  2005年   60篇
  2004年   59篇
  2003年   51篇
  2002年   48篇
  2001年   11篇
  2000年   16篇
  1999年   21篇
  1998年   17篇
  1997年   19篇
  1996年   25篇
  1995年   17篇
  1994年   20篇
  1993年   12篇
  1992年   8篇
  1991年   11篇
  1990年   17篇
  1989年   9篇
  1988年   7篇
  1987年   7篇
  1986年   5篇
  1985年   9篇
  1984年   10篇
  1983年   5篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1979年   8篇
  1978年   4篇
  1977年   6篇
  1976年   9篇
  1975年   6篇
  1974年   7篇
  1971年   4篇
  1970年   3篇
排序方式: 共有1097条查询结果,搜索用时 15 毫秒
1.
2.
Early catch-up growth and subsequent overweight are suggested to be associated with later cardiovascular diseases and later type II diabetes. However, the impact of early catch-up growth and childhood overweight on the development of asthma has been less studied, particularly in children born with very low birth weight (VLBW). A birth cohort of 74 VLBW children (birth weight < or = 1500 g) was followed from birth and investigated on asthma at 12 yr of age. Early rapid weight gain was in one way defined as an increase of weight > or =1 standard deviation score (SDS) at 6 months of corrected postnatal age. Current overweight was defined by body mass index (BMI) exceeding 21.2 and 21.7 kg/m(2), respectively, for boys and girls at 12 yr of age. Current asthma was diagnosed by a pediatrician, according to asthma ever in combination with a positive response to hypertonic saline bronchial provocation test and/or wheeze at physical examination at 12 yr old. Being overweight at 12 yr of age was associated with an increased risk for current asthma in the VLBW children [crude odds ratio (OR): 5.5, 95% confidence interval (CI): 1.3-22.2]. After adjustment for early weight gain and neonatal risk, the OR of overweight increased nearly three times (adjusted OR: 15.3, 95% CI: 2.5-90.6). Early rapid weight gain seemed to be inversely associated with current asthma (adjusted OR: 0.49 for an increase of weight equal to 1 SDS, 95% CI: 0.23-1.02, p = 0.06). In addition, early rapid weight gain was inversely associated with the magnitude of bronchial responsiveness at 12 yr (coefficient -1.15, p < 0.01). There was a strong and positive association between overweight and asthma at 12 yr of age in the VLBW children. This strong association had been reduced by early rapid weight gain, possibly via the reduction of bronchial responsiveness.  相似文献   
3.
4.
During 1984-1985, 410 patients with cervical hip fracture were randomized between 2 methods of internal fixation-a single nail (Rydell) or 2 LIH hook pins (LIH). The patients were followed-up prospectively for at least 2 years. Radiographs were taken after 1 week, 1, 3, 6, 12, and 24 months. The radiographs of the 295 paients alive 2 years postoperatively were examined by one of the authors. The sliding and the diversion of the pins and the nail in the anteroposterior projection and the diversion in the lateral projection were measured. In the failure group (non-union, late segmental collapse), the greatest sliding was noted within 1 month postoperatively and the diversion increased up to 3 months. Significant differences between the failure and the non-failure groups could be seen even after 1 week. We also found that the degree of sliding of the LIH pins and the Rydell nail 1 month postoperatively is comparable to the scintigraphic pattern 2 weeks postoperatively in predicting failure after nternal fixation of cervical hip fractures.  相似文献   
5.
6.
Lindahl's bibliographic essay highlights five books, two doctoral theses, and several journal articles that are Sweden's major contributions to the bioethics literature. The books are H. Fagerberg's edited work on medical ethics (1984), widely used as a textbook in Sweden's medical and nursing schools; G. Wretmark, A. Wretmark, and J. Ludvigsson's co-authored text on ethics in medical care (1983); physician A. Andrén-Sandberg's case book (1986); theologian B. Hanson's collection of essays (1988); and Fagerberg's edited work on the ethics of prenatal diagnosis (1980). The theses are C. Blomquist's (1971), the first in Sweden on medical ethics, and C. Kjellstrand's 1988 work on high technology medicine. The articles include two on medical ethics in Sweden written by Lindahl and published in issues of Theoretical Medicine, the only cited works in English.  相似文献   
7.
Characterization of the count-rate performance of scintillation cameras should include not only the specification of count losses. At high count rates, there is also an image distortion due to the mispositioning of pile-up events. In this paper a simple and clinically relevant procedure to quantify this distortion is presented. The images of a square uniform technetium-99m phantom at high and low count rates are used. The fraction of the total counts being correctly positioned is determined as the peripheral count density divided by the total average count density. This ratio, corrected for the camera non-uniformity at low count rates, is called the positioning ability. According to the National Electrical Manufacturers' Association (NEMA), the system count rate performance with scatter should be reported as the measured count rate giving 20% count losses. In this paper it is suggested that this measure be complemented by a measure of the fraction correct positioned events at this count rate. This fraction, the high count rate positioning ability', can be easily and accurately measured using our method. The method has been tested on two different scintillation cameras. For one of them the high count rate positioning ability was determined as 91% at a measured count rate of 30000 s–1 with 20% count losses. For the other camera, the corresponding figures were 88% at 59000 s–1 and close to 100% at 38000 s–1, before and after the installation of a new pile-up rejection circuit, respectively. Offprint requests to: C. Ceberg  相似文献   
8.
In this prospective randomized multicenter trial 93 patients, median age 72 years, with RAEB-t (n=25) and myelodysplastic syndrome (MDS)-AML (n=68) were allocated to a standard induction chemotherapy regimen (TAD 2+7) with or without addition of granulocyte-macrophage-CSF (GM-CSF). The overall complete remission (CR) rate was 43% with no difference between the arms. Median survival times for all patients, CR patients, and non-CR patients were 280, 550, and 100 days, respectively, with no difference between the arms. Response rates were significantly better in patients with serum lactate dehydrogenase (S-LDH) levels 相似文献   
9.
Leptin and asthma in overweight children at 12 years of age   总被引:1,自引:0,他引:1  
Obesity is suggested as a risk factor for asthma, but the mechanisms are unclear. The relationship between obesity and asthma has not been considered in children born with very low-birth weight (VLBW). We hypothesized that overweight was a contributing factor for asthma in VLBW children, and that leptin and leptin-associated cytokines might play roles in overweight-related asthma. Seventy-four VLBW and 64 normal birth weight (NBW) children participated in a 12-yr follow up study assessing asthma and allergy. Twenty-seven (12 VLBW) of the 138 children were overweight according to the proposed international definition. The diagnosis of current asthma was made by a pediatrician. Serum levels of leptin and interferon (IFN)-gamma were analyzed by enzyme-linked immunosorbent assay (ELISA). Leptin levels were considerably higher in the overweight than in the non-overweight children (median value: 18.1 vs. 2.8 ng/ml, p < 0.001). In the overweight children, current asthmatics had twice as high levels of leptin as children without current asthma (median value: 30.8 vs. 14.3 ng/ml, p = 0.14), but this was not the case in the non-overweight children. IFN-gamma was more often detected in the overweight than in the non-overweight children (61% vs. 12%, p < 0.001), and there was a positive correlation between the levels of leptin and the levels of IFN-gamma (Rho = 0.40, p < 0.001). In the VLBW group, the overweight children had a significantly increased risk for current asthma compared with the non-overweight children after adjustment for the neonatal risk factors [adjusted odds ratio (OR) 5.8, 95% confidence interval (CI): 1.2-27]. Thus, overweight was associated with asthma in the VLBW children. Our hypothesis remained that leptin might be involved in the pathogenesis of asthma in the overweight children, and IFN-gamma might be a pathway in the process of leptin-induced inflammation.  相似文献   
10.
The purpose of this study was to evaluate the reliability of a multidimensional questionnaire for Swedish adults with treated complete unilateral or bilateral cleft lip and palate (CLP). The questionnaire was designed to be used in the evaluation of adults with treated CLP after treatment. Before any conclusions were drawn from the results of the study we assessed the test-retest reliability of the questionnaire. The questionnaire included 168 questions and assessed the following domains: aesthetics, functions associated with CLP, satisfaction with treatment and perceived need for treatment, quality of life, depression and non-specific physical symptoms, body image, and jaw function. The subjects answered the questionnaire twice at a 2-3-week interval. Sixty-one adults (38 men, 23 women) mean age 24 years (range 20-29) participated in the study. The response rate for the questionnaire was acceptable at 75%. The test-retest reliability varied among the different domains. The reliability of questions regarding aesthetics, functions associated with CLP, and treatment satisfaction was good to excellent (intraclass correlation coefficient (ICC) = 0.51 to 0.89). Good to excellent (ICC = 0.61 to 1.0) reliability was also found for the quality of life in various life domains and the wellbeing scales. The reliability of the body image scale was moderate (kappa = 0.43-0.60) for most items and lower than that of other scales used in this study. The reliability of the mean depression symptom score (ICC = 0.93) and the mean non-specific physical symptoms score (ICC = 0.85) were excellent. The reliability of the mandibular function impairment was good (ICC = 0.67). The conclusion of the study is that an overall reliability was good for the multidimensional questionnaire.  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