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   542篇
  免费   47篇
  国内免费   19篇
耳鼻咽喉   2篇
儿科学   8篇
妇产科学   1篇
基础医学   87篇
口腔科学   5篇
临床医学   46篇
内科学   112篇
皮肤病学   121篇
神经病学   6篇
特种医学   61篇
外科学   74篇
综合类   10篇
预防医学   5篇
眼科学   2篇
药学   17篇
肿瘤学   51篇
  2019年   3篇
  2018年   7篇
  2017年   7篇
  2016年   6篇
  2015年   9篇
  2014年   13篇
  2013年   10篇
  2012年   12篇
  2011年   15篇
  2010年   13篇
  2009年   19篇
  2008年   25篇
  2007年   30篇
  2006年   18篇
  2005年   29篇
  2004年   23篇
  2003年   27篇
  2002年   18篇
  2001年   15篇
  2000年   17篇
  1999年   21篇
  1998年   13篇
  1997年   10篇
  1996年   15篇
  1995年   8篇
  1994年   16篇
  1993年   18篇
  1992年   11篇
  1991年   12篇
  1990年   8篇
  1989年   15篇
  1988年   12篇
  1987年   19篇
  1986年   17篇
  1985年   10篇
  1984年   5篇
  1983年   14篇
  1982年   9篇
  1981年   9篇
  1980年   8篇
  1979年   8篇
  1978年   3篇
  1977年   2篇
  1976年   3篇
  1975年   2篇
  1974年   5篇
  1973年   12篇
  1971年   2篇
  1969年   2篇
  1966年   1篇
排序方式: 共有608条查询结果,搜索用时 15 毫秒
61.
Cranial bone flap fixation clamps: compatibility at MR imaging   总被引:2,自引:0,他引:2  
Shellock  FG; Shellock  VJ 《Radiology》1998,207(3):822
  相似文献   
62.
63.
64.
Abstrakt  Der wirtschaftliche Vorteil einer Vertragsarztzulassung stellt kein gesondert zu bewertendes Wirtschaftsgut dar, sondern einen wertbildenden Faktor des Wirtschaftsguts “Praxiswert” im Rahmen des Gesamtkaufpreises zum Erwerb der Vertragsarztpraxis.  相似文献   
65.

BACKGROUND:

Cancer at both the primary site and in the lymph nodes is associated with lethality, although the mechanism by which lethality arises from each site has been poorly understood. For breast carcinoma, each positive lymph node contributes an approximately 6% risk of death, and each millimeter of primary tumor greatest dimension contributes approximately 1%; whereas, for melanoma, each positive lymph node contributes an approximately 23% risk, and each millimeter of tumor thickness contributes approximately 8%: This is described by a pair of linked equations, the Size+Nodes method.

METHODS:

A simple expression, the ProbabilityEstimation equation, which was derived from the authors' binary‐biologic model of cancer metastasis, was used to calculate the probabilities of spread of cancer cells from data on tumor size, lymph node status, and death rate.

RESULTS:

In this report, the authors demonstrated, that when similar masses of cancer are compared, the chance of lethal spread of a cancer cell to the periphery is approximately the same whether the spread emerges from a lymph node or from the primary site. The greater the number of cells at the primary site (tumor size) or the greater the number of cells in the lymph nodes (number of positive lymph nodes), the greater is the aggregate chance that 1 or more cells has undergone a lethal event of spread, a process captured by the Size+Nodes equations.

CONCLUSIONS:

The lethal contributions of cancer at the primary site and lymph nodes can be explained by a simple mechanical process of the spread of cancer cells occurring with definable probabilities per cell. The presence of cancer in the lymph nodes does not indicate an intrinsic change in a malignancy but, rather, an increased mass of cancer from which spread can emerge. Cancer 2009. © 2009 American Cancer Society.  相似文献   
66.
Thirteen variables were studied for their relative usefulness in predicting recurrent disease in 107 patients with clinical Stage I melanoma of the upper extremity. After a mean follow-up period of 54 months, the only patents who have had recurrent disease to date are those who primary lesions were located either on the hand or posterior upper arm. The five-year disease-free survival role for 44 patients with melanoma at these sites was 68%. None of 63 patients with melanoma located on the forearm of anterior upper arm have had recurrent disease (i.e., the five-year, disease-free survival rate was 100% (p = 0.00004), compared with the hand or posterior arm group). A Cox proportional hazards (multivariate) analysis demonstrated that two primary tumor histologic variable, thickness in millimeters and ulceration, interacted to produce the best prognostic model for those 44 patients with melanoma of the hand or posterior upper arm. Twenty-one patients with primary lesions at these sites had primary tumors less than 2.25 mm in thickness and no evidence of ulceration histologically. Their five-year, disease-free survival role was 95%. For the remaining 23 patients with primary tumors on the hand or posterior upper arm who had either histologic evidence of ulceration or primary tumors greater than or equal to 2.25 mm, the five-year disease-free survival rate was 37% (p = 0.002, compared with group nonulcerated, thin lesions). The excellent survival rate for patients with melanomas on the forearm or anterior upper arm was not completely explained by pathologic stage, by primary tumor thickness, or by histologic ulceration of the primary tumor.  相似文献   
67.
68.
The end-tidal carbon dioxide tension (PetCO2) measured after a single, large tidal-volume breath (15 ml/kg body weight) was compared to simultaneous measurements of PaCO2 in 6 dogs with normal lungs who were receiving high-frequency jet ventilation (HFJV). There was an excellent linear correlation between PetCO2 and the PaCO2 over the entire range of CO2 tensions commonly encountered in clinical practice (PetCO2 = 0.9 PaCO2 + 2.2 torr; n = 51, r = .98, p less than .001, range of PaCO2 = 12-72 torr). We conclude that when lung function is normal, a simple system of measuring PetCO2 after a large breath is an accurate method of monitoring the effectiveness of CO2 elimination during HFJV.  相似文献   
69.
70.
Cutaneous malignant mixed tumor   总被引:1,自引:0,他引:1  
Two cases of cutaneous malignant mixed tumor occurred in a 70-year-old man and a 69-year-old man. Nine previously described patients with cutaneous malignant mixed tumor resembled the two patients in this report, both clinically and histologically. All cases with adequate long-term follow-up evaluations were characterized by recurrence or metastasis. In contrast to benign mixed tumors, these tumors tend to occur on the extremities, are of larger size, and may exhibit rapid growth. Histologically, cellular atypism, increased cellularity, increased mitotic rate, invasion of surrounding tissue, and necrosis may be identified.  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