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   945篇
  免费   52篇
  国内免费   4篇
儿科学   14篇
妇产科学   9篇
基础医学   85篇
口腔科学   7篇
临床医学   93篇
内科学   158篇
皮肤病学   5篇
神经病学   22篇
特种医学   95篇
外科学   130篇
综合类   29篇
预防医学   91篇
眼科学   17篇
药学   86篇
中国医学   5篇
肿瘤学   155篇
  2023年   3篇
  2022年   8篇
  2021年   10篇
  2020年   6篇
  2019年   16篇
  2018年   15篇
  2017年   12篇
  2016年   16篇
  2015年   15篇
  2014年   29篇
  2013年   53篇
  2012年   55篇
  2011年   65篇
  2010年   42篇
  2009年   40篇
  2008年   66篇
  2007年   55篇
  2006年   56篇
  2005年   41篇
  2004年   40篇
  2003年   40篇
  2002年   30篇
  2001年   13篇
  2000年   11篇
  1999年   17篇
  1998年   18篇
  1997年   18篇
  1996年   21篇
  1995年   17篇
  1994年   10篇
  1993年   13篇
  1992年   10篇
  1991年   7篇
  1990年   8篇
  1989年   14篇
  1988年   12篇
  1987年   12篇
  1986年   11篇
  1985年   13篇
  1984年   8篇
  1983年   7篇
  1982年   10篇
  1981年   7篇
  1980年   3篇
  1979年   5篇
  1978年   5篇
  1977年   8篇
  1976年   4篇
  1975年   2篇
  1968年   1篇
排序方式: 共有1001条查询结果,搜索用时 31 毫秒
51.
BACKGROUND: Research has recently adopted the use of social-ecological models in the study of physical activity. Few studies, however, have addressed the influence of the environment on activity using Geographic Information System (GIS)-derived measures of environmental attributes and self-report ratings of other environmental attributes. Even fewer have examined walking behaviors. METHODS: Self-report measures of physical activity, social support, self-efficacy, and perceived neighborhood environment were obtained by means of a Computer-Assisted-Telephone-Interview (CATI) survey of 1,281 residents of Rockhampton, Queensland. Over 94% (1,215) of respondents' residential locations were successfully geocoded into the existing city council GIS database. The self-report data, along with GIS-derived measures, were used to determine the relationships among selected variables of the neighborhood environment for each geocoded location. RESULTS: GIS-derived measures of street connectivity and proximity to parkland, the number of active people in a 1-km radius, and self-reported perceptions of neighborhood cleanliness showed associations with the likelihood of achieving sufficient levels of physical activity when adjusting for selected psychosocial variables. GIS-derived Euclidian distance to footpath networks, number of dogs in 0.8-km radius, network distance to newsagents, and perceptions of footpath condition were significantly associated with the likelihood of participating in any recreational walking. CONCLUSION: Environmental characteristics were found to have differential influences on the two selected measures of physical activity. Aesthetics and safety appear to be important influences of physical activity, whereas proximal footpaths showed increased likelihood of participation in recreational walking. It is proposed that the strength of association between the environmental and physical activity may be improved if future research utilizes a Geographic Information System approach to the study of restricted geographical areas.  相似文献   
52.
53.
54.
J R Michael  W E Mitch 《JAMA》1976,236(24):2773-2775
A 38-year old woman receiving phenytoin (diphenylhydantoin) noticed maculopapular erythema as the first manifestation of a syndrome that included acute renal failure and myositis in addition to fever, lymphadenopathy, exfoliative dermatitis, and hepatitis. Prednisolone sodium phosphate therapy resulted in resolution of this hypersensitivity reaction, and she recovered from renal insufficiency. The occurrence of renal failure and myositis in the spectrum of phenytoin hypersensitivity reactions is discussed, and the importance of a morbilliform rash in a patient receiving phenytoin is emphasized.  相似文献   
55.
Mechanisms by which gastroplasty for morbid obesity causes weight loss are poorly understood. We studied the role of altered gastric emptying in 50 patients before surgery, 1-4 weeks after surgery, and 2-24 months after surgery using technetium-99m pentetate in water for liquid meals and a Tc-99m styrene divinylbenzene copolymer resin in oatmeal for semisolid meals. We determined the emptying half-times of the stomach before and after surgery in the proximal and distal compartments. The proximal compartment emptied promptly in the early and late postoperative periods. The distal compartment emptied liquids at rates similar to those before surgery, while the late postoperative emptying of semisolids was significantly faster. The stoma connecting the two compartments thus permits rapid transit of liquids and semisolids without delay of distal compartment emptying. No correlation was seen between the emptying half-times or changes thereof and eventual weight loss. Delayed gastric emptying is therefore not the mechanism for satiety and weight loss after gastroplasty has been performed.  相似文献   
56.
Despite advances in the treatment of many side effects associated with chemotherapy, alopecia remains an issue that is difficult to resolve. Chemotherapy-induced alopecia (CIA) is a condition that can have profound psychosocial and quality-of-life consequences, resulting in anxiety, depression, a negative body image, lowered self-esteem, and a reduced sense of well-being. Patients who fear CIA may sometimes select regimens with less favorable outcomes or may refuse treatment. When supporting patients with CIA, health care providers should use an individualized approach with a focus placed on the actual moment of hair loss. Education, support groups, and self-care strategies are important components of any management approach. No treatment modality for preventing CIA has been clearly shown to be effective. Recent evidence suggests that new scalp hypothermic regimens may be safe and effective. There remains a critical need for effective new approaches to this problem.  相似文献   
57.
58.
59.

Background

Farnesyl protein transferase inhibitors (FTIs) were originally developed to inhibit oncogenic ras, however it is now clear that there are several other potential targets for this drug class. The FTI tipifarnib (ZARNESTRA?, R115777) has recently demonstrated clinical responses in adults with refractory and relapsed acute leukemias. This study was conducted to identify genetic markers and pathways that are regulated by tipifarnib in acute myeloid leukemia (AML).

Methods

Tipifarnib-mediated gene expression changes in 3 AML cell lines and bone marrow samples from two patients with AML were analyzed on a cDNA microarray containing approximately 7000 human genes. Pathways associated with these expression changes were identified using the Ingenuity Pathway Analysis tool.

Results

The expression analysis identified a common set of genes that were regulated by tipifarnib in three leukemic cell lines and in leukemic blast cells isolated from two patients who had been treated with tipifarnib. Association of modulated genes with biological functional groups identified several pathways affected by tipifarnib including cell signaling, cytoskeletal organization, immunity, and apoptosis. Gene expression changes were verified in a subset of genes using real time RT-PCR. Additionally, regulation of apoptotic genes was found to correlate with increased Annexin V staining in the THP-1 cell line but not in the HL-60 cell line.

Conclusions

The genetic networks derived from these studies illuminate some of the biological pathways affected by FTI treatment while providing a proof of principle for identifying candidate genes that might be used as surrogate biomarkers of drug activity.
  相似文献   
60.
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