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   1169篇
  免费   51篇
  国内免费   8篇
耳鼻咽喉   73篇
儿科学   37篇
妇产科学   30篇
基础医学   75篇
口腔科学   33篇
临床医学   89篇
内科学   208篇
皮肤病学   35篇
神经病学   42篇
特种医学   55篇
外科学   302篇
综合类   19篇
预防医学   45篇
眼科学   88篇
药学   57篇
中国医学   2篇
肿瘤学   38篇
  2023年   5篇
  2022年   11篇
  2021年   30篇
  2020年   20篇
  2019年   30篇
  2018年   40篇
  2017年   31篇
  2016年   43篇
  2015年   48篇
  2014年   71篇
  2013年   68篇
  2012年   82篇
  2011年   75篇
  2010年   43篇
  2009年   38篇
  2008年   78篇
  2007年   108篇
  2006年   106篇
  2005年   91篇
  2004年   52篇
  2003年   65篇
  2002年   37篇
  2001年   12篇
  2000年   4篇
  1998年   4篇
  1997年   6篇
  1996年   4篇
  1995年   2篇
  1993年   1篇
  1992年   2篇
  1991年   7篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1985年   2篇
  1984年   2篇
  1978年   1篇
  1972年   1篇
  1968年   1篇
  1966年   1篇
排序方式: 共有1228条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Background/purpose: The localized or generalized skin thickness detected on mammography may reflect an underlying pathology of breast or a systemic disease involving the skin. The aim of this report is to describe the range of normal breast skin thickness in women using a film-screen mammographic technique.
Methods: Measurement of the mammographic skin thickness over different parts of the breast was performed in 144 women who had normal findings in a combined mammographic and ultrasonographic examination. Patients were grouped as premenopause, postmenopause and surgical menopause who were under continuous oestrogen treatment. The skin thickness in four regions (superior, inferior, medial, lateral) of both breasts was compared, and their relations with age, breast size, menopausal and hormonal status were investigated. The interobserver reliability was tested in a small subgroup of patients.
Results: Interobserver agreement was good for all measurements. The range of normal breast skin thickness was between 0.50 and 3.10 mm. There were no differences in skin thickness between the corresponding regions of the breasts, with significant differences between the regions in the same breast. While breast size increased with age, skin thickness decreased in all regions.
Conclusion: The breast size, age, regional variations and hormonal status of the patients should be considered when defining the normal range of skin thickness in mammographic examinations. We assume that upper limit of mammographic skin thickness should be set as 3.0 mm, regardless of the focal spot size and film-focus distance.  相似文献   
5.
6.
Metastatic eyelid tumours are rare and account for less than 2% of all eyelid neoplasms. We report a case of metastatic breast carcinoma to the eyelid in a 60-year-old Chinese lady presenting with a 2-year history of enlarging, painless nodular lower eyelid swelling. The 1 cm diameter lesion was provisionally diagnosed as a sebaceous cyst. However the excision biopsy revealed a mucinous carcinoma expressing oestrogen receptor protein. She had a past history of mastectomy one year previously and histology showed an infiltrating ductal carcinoma (oestrogen receptor status negative) without evidence of axillary lymph node metastasis. She had completed adjuvant radio- and chemotherapy. Further treatment of the current lesion involved a wide excision which did not show any residual malignancy. She had no other evidence of metastasis and was treated with letrozol. We highlight this case to create awareness among clinicians and opthalmologists on the possibility of metastatic disease as a cause of eyelid swelling, especially in patients with a history of cancer. It may also be the first sign of metastatic disease of an internal malignancy. A review of the literature is also presented.  相似文献   
7.
Seasonal changes in blood plasma biochemistry of siraz Capoeta capoeta umbla were determined throughout 1 year. In the present study, while the highest values for glucose and globulin were found in winter, the values for increased activities of total protein, albumin, calcium, sodium levels, albumin/globulin ratio, lactate dehydrogenase, and alkaline phosphatase were determined in summer. We determined that blood biochemistry values of siraz, which were positively affected by water temperature and pH, except glucose and globulin. Glucose and globulin were negatively affected by water temperature and pH. Consequently, it was concluded that the seasons are key factors when blood parameters are used as biomarkers for environmental alterations. It is difficult to define the most important factors affecting seasonal changes of blood biochemistry in fish.  相似文献   
8.
BackgroundR Rapid fluid resuscitation is a crucial therapy during the treatment of patients with extensive burns. In 1968, the Parkland Formula was introduced for the calculation of the estimated volume of the resuscitation fluid. Since then, different methods for the calculation of fluid resuscitation volume have been developed. We aimed to evaluate if the Parkland formula is still the most effective method for fluid resuscitation volume calculation in burn patients.MethodsIn the period between January 2015 and January 2019, data from 569 patients over 16 years old with burns of more than 20% total body surface area (TBSA) and at least 15% TBSA full thickness burns were entered in the German burn registry. The patients were divided into 5 groups (0, +1, ?1, +2, ?2) according to the volume of the resuscitation fluid they received. Group 0 patients received the amount of fluid calculated according to the Parkland formula (n = 83). The 4 other groups received reduced (-1, -2) or increased (+1, +2) fluid volumes in comparison to the value obtained by the Parkland formula.ResultsPatients in Group 0 presented a significantly lower mortality in the first week (4.5%) compared to groups –2 (16.7%) and group +2 (19.5%) (p = 0.021). Furthermore, the mean number of operations in group +2 (5.81) was higher than in group ?2 (3.81). Surviving patients from group +2 presented a longer hospital stay (68.1 days) compared to the other groups. Additionally, the logistic regression analysis showed a higher survival of patients in groups ?2 and ?1 (regression coefficients ?0.11 and ?0.086; Odds Ratio 0.896 and 0.918; 95% Confidence Interval (CI) 0,411–1.951 and 0.42–2.004).ConclusionIn this retrospective study, register based analysis a restrictive fluid regime was associated with a higher survival compared to the liberal Parkland guided fluid regime.  相似文献   
9.
An extensive iodine deficiency disorders survery was conducted in Bangladesh in 1993 to assess the latest iodine nutriture status of the country. The clinical variables of the survey were goitre and cretinism, and the biochemical variable was urinary iodine. The “EPI-30 cluster” sampling methodology was followed for selecting the survey sites. In each survey site, the study population consisted of boys and girls, aged 5–11 years, and men and women, aged 15–44 years, in about equal populations. the total number of survey sites was 78 and the total number of respondents was 30 072. The total number of urine samples was 4512 (15% sub-sample). The current total goitre rate (grade 1+grade 2) in Bangladesh is 47.1% (hilly, 44.4%; flood-prone, 50.7%; and plains, 45.6%). The prevalence of cretinism in the country is 0.5% (hilly, 0.8%; flood-prone, 0.5%; and plains, 0.3%). Nearly 69% of Bangladeshi population have biochemical iodine deficiency (urinary iodine excretion [UIE]<10 mg/dl) (hilly, 84.4; flood-prone, 67.1%; and plains 60.4%). Women and children are more affected than men, in terms of both goitre prevalence and UIE. The widespread severe iodine deficiency in all ecological zones indicates that the country as a whole is an iodine-deficient region. Important recommendations of global interest are made from the experience of the survey. An erratum to this article is available at .  相似文献   
10.
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