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   469篇
  免费   25篇
  国内免费   1篇
耳鼻咽喉   22篇
儿科学   41篇
妇产科学   2篇
基础医学   51篇
口腔科学   3篇
临床医学   49篇
内科学   72篇
皮肤病学   4篇
神经病学   29篇
特种医学   18篇
外科学   67篇
综合类   13篇
预防医学   69篇
眼科学   9篇
药学   22篇
肿瘤学   24篇
  2022年   3篇
  2021年   12篇
  2020年   7篇
  2019年   8篇
  2018年   15篇
  2017年   5篇
  2016年   5篇
  2015年   10篇
  2014年   12篇
  2013年   18篇
  2012年   25篇
  2011年   13篇
  2010年   19篇
  2009年   8篇
  2008年   16篇
  2007年   15篇
  2006年   16篇
  2005年   13篇
  2004年   14篇
  2003年   19篇
  2002年   14篇
  2001年   18篇
  2000年   17篇
  1999年   13篇
  1998年   4篇
  1997年   4篇
  1996年   4篇
  1995年   7篇
  1994年   4篇
  1993年   5篇
  1992年   5篇
  1991年   12篇
  1990年   10篇
  1989年   3篇
  1988年   8篇
  1986年   3篇
  1985年   6篇
  1983年   5篇
  1982年   4篇
  1980年   6篇
  1979年   7篇
  1978年   4篇
  1977年   9篇
  1976年   7篇
  1975年   4篇
  1974年   9篇
  1970年   4篇
  1967年   4篇
  1944年   5篇
  1943年   5篇
排序方式: 共有495条查询结果,搜索用时 156 毫秒
1.
2.
A follow-up study that tracked a sample of 133 people released from a state mental hospital showed that 35 percent became homeless within three months, supporting the theory that deinstitutionalization contributes to homelessness. An in-depth, qualitative tracking procedure provides data to describe key characteristics of the homeless person and the process by which people become homeless. These data point to solutions for improved care of severely mentally disabled people for whom the aftercare system has failed.  相似文献   
3.
Background: Angiogenesis is essential for tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor identified to date. TGFβ-1 acts as an indirect angiogenic agent. Methods: VEGF and TGFβ-1 were measured in the serum of breast cancer patients and agematched controls and in tumor tissue of cancer patients by ELISA. VEGF protein and mRNA expression by breast tumor cell lines were examined, and the effect of TGFβ-1 on VEGF production in these cells was assessed. Results: VEGF levels were significantly higher (P=.03) in the serum of patients with breast cancer compared to age-matched controls. A positive correlation was found between serum (r=0.539) and tumor tissue (r=0.688) levels of VEGF and TGFβ-1. Metastatic MDA-MB-231 breast cancer cells produce more VEGF than do the primary BT474 cells. TGFβ-1 significantly (P<.05) increased production of VEGF. Conclusions: Breast cancer cells constitutively produce VEGF protein and mRNA. There is a relationship between VEGF and TGFβ-1 levels in breast cancer patients, and TGFβ-1 regulates VEGF expression by breast cancer cells. Presented at the 50th Annual Cancer Symposium of the Society of Surgical Oncology, Chicago, Illinois, March 20–23, 1997.  相似文献   
4.
The development of an institutional culture cannot be left to chance. One must articulate the desirable managerial variables that will establish the mores of and for the institution. When these are known and become the basis for the actions and activities of those who are part of the institution, the operational results will be satisfactory and desirable.  相似文献   
5.
6.
White cell infiltration of solid tumors is an important prognostic indicator in malignant disease. Although macrophage infiltration is associated with good outcome in colorectal cancer, a high macrophage content is associated with poor prognosis in breast cancer. Suppressor macrophages prevent T cell activation in normal tissues such as mucosal linings exposed to continuous antigenic challenge. Interleukin 10 (IL-10), an immunosuppressive cytokine, inhibits macrophage co-stimulation of T cells. Suppressor macrophage numbers, T cell numbers and T cell activation status were assessed in cell suspensions obtained from fresh specimens of breast and colorectal tumours and matched normal tissues. IL-10 production by both malignant and matched normal tissue was also assessed. This study identified elevated numbers of suppressor macrophages in breast tumors compared to matched normal breast tissue. Colorectal tumors did not contain significant numbers of these cells. Although T cell numbers are increased in breast tumors, these cells do not appear to be fully activated, as assessed by major histocompatibility complex class II and Interleukin 2 receptor expression. In contrast, T cells in colorectal tumors exhibit greater expression levels of these markers. Breast tumors produce significantly higher levels of IL-10 than normal breast tissue whereas IL-10 levels in colorectal tumors are similar to normal colon tissue. Our findings of high suppressor macrophage numbers, high levels of IL-10 and poorly activated T cells in breast tumors compared to low suppressor macrophage numbers, low IL-10 and fully activated T cells in colorectal tumors may explain why high macrophage content is associated with poor prognosis in breast cancer and good prognosis in colorectal malignancy.  相似文献   
7.
8.
9.
OBJECTIVES: Many establishments serve alcoholic beverages to obviously intoxicated patrons despite laws against such sales. To guide the development of interventions to reduce these illegal alcohol sales, this study used actors feigning intoxication to determine whether servers recognized obvious signs of intoxication and to assess the tactics servers used when dealing with intoxicated patrons. METHODS: Male actors ages 30 to 50 acted out signs of obvious intoxication as they attempted to purchase alcoholic beverages. If served during the first attempt, these pseudo-intoxicated buyers made second purchase attempts during the same visit. Observers accompanied the actors; after each visit, actors and observers recorded the servers' behavior and comments. RESULTS: Alcoholic beverages were served to actors portraying intoxicated patrons at 68% of first purchase attempts and 53% of second purchase attempts (62% of a total of 106 purchase attempts). The most common refusal technique was a direct refusal (68% of refusals), made with either no excuse or with reference to the actors' apparent intoxication level. Servers' second most commonly used refusal technique was offering alcohol-free beverages, such as coffee or water (18% of refusals). CONCLUSIONS: Further research is needed to determine why servers who recognize intoxication serve alcoholic beverages and what training, outlet policies, and external pressures are needed to reduce illegal alcohol sales to obviously intoxicated patrons.  相似文献   
10.
Spiritual moments can occur at unexpected times and it is often upon reflection that the significance of the moment is understood. The author tells a personal story about her daughter and herself engaged in the activity of drawing flowers. The reflection which follows highlights both the process and outcomes of the experience. Exploring spiritual issues using this narrative medium assists health care workers to recognize better and understand spirituality in relation to the occupation of visual art.  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