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   2735151篇
  免费   204611篇
  国内免费   6046篇
耳鼻咽喉   36178篇
儿科学   90598篇
妇产科学   75616篇
基础医学   387539篇
口腔科学   77748篇
临床医学   247866篇
内科学   536278篇
皮肤病学   62793篇
神经病学   217837篇
特种医学   103123篇
外国民族医学   696篇
外科学   411678篇
综合类   63981篇
现状与发展   7篇
一般理论   951篇
预防医学   209555篇
眼科学   64129篇
药学   197153篇
  7篇
中国医学   6594篇
肿瘤学   155481篇
  2019年   21940篇
  2018年   31489篇
  2017年   23859篇
  2016年   26556篇
  2015年   29940篇
  2014年   41998篇
  2013年   62296篇
  2012年   85408篇
  2011年   90535篇
  2010年   53383篇
  2009年   50306篇
  2008年   83759篇
  2007年   88905篇
  2006年   89755篇
  2005年   86379篇
  2004年   83126篇
  2003年   79231篇
  2002年   76383篇
  2001年   138686篇
  2000年   142185篇
  1999年   117719篇
  1998年   32341篇
  1997年   28533篇
  1996年   28607篇
  1995年   27371篇
  1994年   24987篇
  1993年   23254篇
  1992年   89745篇
  1991年   86140篇
  1990年   82891篇
  1989年   79569篇
  1988年   72826篇
  1987年   71168篇
  1986年   66666篇
  1985年   63489篇
  1984年   47414篇
  1983年   40117篇
  1982年   23387篇
  1981年   20811篇
  1979年   41818篇
  1978年   29110篇
  1977年   24491篇
  1976年   23047篇
  1975年   23970篇
  1974年   29015篇
  1973年   27990篇
  1972年   26066篇
  1971年   23910篇
  1970年   22538篇
  1969年   21018篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly malignant tumour with a poor prognosis. Patients present with signs of steroid hormone excess (e.g., Cushing's syndrome) or symptoms due to an abdominal mass. DIAGNOSIS: In case of an adrenal mass, hormonal workup before surgery is required for differential diagnosis, perioperative management, and for follow-up. The imaging of choice is CT or MRI with MRI being of additional use when invasion of big vessels is suspected. Apart from that, the use of 18-FDG-PET is becoming increasingly established. TREATMENT: Surgical resection is the therapeutic option of choice in stages 1 - 3. In stage 4, the adrenolytic compound mitotane is part of the first-line treatment, but often needs to be combined with cytotoxic chemotherapy. Most patients will eventually have a recurrence, so adjuvant treatment (mitotane/tumour bed radiation) has to be considered in high risk patients, even if randomized controlled trials on adjuvant treatment are still lacking. STRUCTURAL PROGRESS: Several national and European structures have recently been established in order to increase our knowledge of ACC, improve therapeutic options and diagnostic procedures, and promote research. GANIMED, as a Germany-wide network of experts on adrenal diseases, has been founded allowing for improved gathering of data and joint studies. ENSAT (European Network for the Study of Adrenal Tumours) has been brought to life, aiming at European standards for therapy, diagnosis and tumour banking. Since 2003, patients can be enrolled in the German ACC Registry. France and Italy have also developed a central registry to collect nationwide data from patients with ACC. For the first time, patients with metastatic/unresectable ACC can participate in a prospective controlled randomized trial comparing two different cytotoxic chemotherapy regimes (FIRM-ACT).  相似文献   
22.
The overnight one-mg dexamethasone suppression test has been used for many years to screen for Cushing's syndrome. This test has usually been evaluated in controls versus patients with severe hypercortisolism. Under these conditions, the overnight dexamethasone suppression test has been reported to have high sensitivity and specificity. The objective of this study was to determine the sensitivity of the one mg overnight dexamethasone suppression test in patients with mild and/or periodic Cushing's syndrome. Therefore, an overnight dexamethasone suppression test was performed in 17 consecutive patients presenting to an endocrinology clinic with signs and symptoms of hypercortisolemia who were later proven to have Cushing's syndrome. The majority of patients were found to have both mild and periodic hypercortisolism. One mg of dexamethasone was given at midnight and a plasma cortisol was measured by radioimmunoassay at 08:00 the following morning. Using a cut-off for a morning cortisol following overnight dexamethasone of > 5 microg/dL, only three of 17 patients failed to suppress to a value less than this cut-off (sensitivity 18 %). A cut-off of > 2 microg/dL gave similar sensitivity. Even with a stringent cut-off point of > 1.8 microg/dL, only seven of 17 patients failed to suppress to a value less than this cut-off point (sensitivity of 41 %). These results demonstrate that the great majority of patients with mild and/or periodic Cushing's syndrome suppress to overnight dexamethasone. Since patients with mild and/or periodic Cushing's syndrome are the patients in whom the identification of hypercortisolism is difficult, our results from this relatively small study suggest that this test should no longer be used to exclude these patients from further workup for Cushing's syndrome.  相似文献   
23.
The present study compared four different sites and conditions for the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) in 38 spontaneous breathing tracheotomised patients. Of the patients, 28 had chronic obstructive pulmonary disease (COPD). The four different conditions were: 1) through a cuff inflated cannula (condition A); 2) through the mouth with a deflated cannula (condition B); 3) through the mouth with a phonetic uncuffed cannula (condition C); and 4) through the mouth after stoma closure (condition D). Five trials in each condition were performed using a standardised method. The measurement of both MIP and MEP differed significantly depending on the condition of measurement. MIP taken in condition A was significantly higher when compared with conditions B, C and D. MEP in condition A was significantly higher when compared with condition B and D. In condition A the highest frequency of the best measurement of MIP and MEP was observed at the fourth and fifth effort, respectively. The same results were obtained after the selection of only COPD patients. In conclusion, respiratory muscle assessment differs significantly depending on measurement condition. Measurement through inflated cannula tracheotomy yields higher values of both maximal inspiratory and maximal expiratory pressure.  相似文献   
24.
25.
Summary: A female patient with isovaleric acidaemia had a successful outcome from pregnancy.  相似文献   
26.
27.
28.
29.
30.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  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