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   545篇
  免费   25篇
  国内免费   12篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   5篇
基础医学   48篇
口腔科学   26篇
临床医学   60篇
内科学   124篇
皮肤病学   3篇
神经病学   8篇
特种医学   74篇
外科学   61篇
综合类   18篇
预防医学   28篇
眼科学   1篇
药学   59篇
中国医学   1篇
肿瘤学   52篇
  2023年   4篇
  2022年   4篇
  2021年   5篇
  2020年   9篇
  2019年   6篇
  2018年   10篇
  2017年   6篇
  2016年   13篇
  2015年   7篇
  2014年   13篇
  2013年   17篇
  2012年   11篇
  2011年   11篇
  2010年   17篇
  2009年   28篇
  2008年   14篇
  2007年   26篇
  2006年   9篇
  2005年   9篇
  2004年   8篇
  2003年   13篇
  2002年   7篇
  2001年   11篇
  2000年   6篇
  1999年   9篇
  1998年   30篇
  1997年   33篇
  1996年   33篇
  1995年   28篇
  1994年   24篇
  1993年   20篇
  1992年   16篇
  1991年   10篇
  1990年   14篇
  1989年   19篇
  1988年   16篇
  1987年   18篇
  1986年   6篇
  1985年   6篇
  1983年   2篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1979年   2篇
  1977年   6篇
  1976年   4篇
  1975年   3篇
  1973年   2篇
  1972年   2篇
  1966年   2篇
排序方式: 共有582条查询结果,搜索用时 15 毫秒
91.
It is now clear that parenteral growth hormone (GH) therapy stimulates growth and increases the adult stature of girls with Turner syndrome. In addition, oestrogens are given to almost all girls with this syndrome because of primary hypogonadism. Oestrogens influence both growth and maturation of the epiphyseal growth plates. Therefore, the form and timing of oestrogen therapy may have an important impact on the outcome of other growth-promoting therapies. To examine the impact of the timing of oestrogen initiation on growth, a randomized trial was conducted in patients with Turner syndrome who were receiving GH. Some patients received oestrogen at 12 years of age, while in others this treatment was not started until 15 years of age. Those girls that received oestrogen later were significantly taller as adults. The single most important factor in determining height gain appeared to be the number of years of GH therapy prior to the initiation of oestrogen treatment.  相似文献   
92.
93.
94.
Bone sarcomas in Paget disease: a study of 85 patients   总被引:5,自引:0,他引:5  
Smith  J; Botet  JF; Yeh  SD 《Radiology》1984,152(3):583-590
This is a comprehensive review of 85 patients who had bone sarcoma associated with Paget disease and who were seen at Memorial Sloan-Kettering Cancer Center between 1927 and 1982. There was an almost equal distribution of tumors in the axial and the appendicular skeletons. The pelvis, humerus, femur, and skull were the tumor sites in 80% of cases. The tumors were bulky large soft tissue masses. Lytic lesions were more common than sclerotic lesions. Mixed lytic and sclerotic lesions were much less common than either single type. Periosteal reaction was uncommon and found in less than 7%. Methylene diphosphonate scans of the bone often showed a cold area that was associated with marked increase in uptake on the gallium scan. Angiography, which was performed in 13 patients, was useful, but CT was much more helpful in showing the soft tissue mass as well as the extent of bony disease. Only three patients in this study survived for five years. Present chemotherapy protocols were disappointing in the treatment of this highly lethal tumor.  相似文献   
95.
Authors – Weinberg SM, Naidoo SD, Bardi KM, Brandon CA, Neiswanger K, Resick JM, Martin RA, Marazita ML Objective – Various lines of evidence suggest that face shape may be a predisposing factor for non‐syndromic cleft lip with or without cleft palate (CL/P). In the present study, 3D surface imaging and statistical shape analysis were used to evaluate face shape differences between the unaffected (non‐cleft) parents of individuals with CL / P and unrelated controls. Methods – Sixteen facial landmarks were collected from 3D captures of 80 unaffected parents and 80 matched controls. Prior to analysis, each unaffected parent was assigned to a subgroup on the basis of prior family history (positive or negative). A geometric morphometric approach was utilized to scale and superimpose the landmark coordinate data (Procrustes analysis), test for omnibus group differences in face shape, and uncover specific modes of shape variation capable of discriminating unaffected parents from controls. Results – Significant disparity in face shape was observed between unaffected parents and controls (p < 0.01). Notably, these changes were specific to parents with a positive family history of CL / P. Shape changes associated with CL / P predisposition included marked flattening of the facial profile (midface retrusion), reduced upper facial height, increased lower facial height, and excess interorbital width. Additionally, a sex‐specific pattern of parent‐control difference was evident in the transverse dimensions of the nasolabial complex. Conclusions – The faces of unaffected parents from multiplex cleft families displayed meaningful shape differences compared with the general population. Quantitative assessment of the facial phenotype in cleft families may enhance efforts to discover the root causes of CL /P.  相似文献   
96.
A series of aralkylphenoxyethylamine and aralkylmethoxyphenylpiperazine compounds was synthesized and their in vitro pharmacological profile at both 5-HT(1A) receptors and α(1)-adrenoceptor subtypes was measured by binding assay and functional studies. The results showed that the replacement of the 1,3-dioxolane ring by a tetrahydrofuran, cyclopentanone, or cyclopentanol moiety leads to an overall reduction of in vitro affinity at the α(1)-adrenoceptor while both potency and efficacy were increased at the 5-HT(1A) receptor. A significant improvement of 5-HT(1A)/α(1) selectivity was observed in some of the cyclopentanol derivatives synthesized (4acis, 4ccis and trans). Compounds 2a and 4ccis emerged as novel and interesting 5-HT(1A) receptor antagonist (pK(i) = 8.70) and a 5-HT(1A) receptor partial agonist (pK(i) = 9.25, pD(2) = 9.03, E(max) = 47%, 5-HT(1A)/α(1a) = 69), respectively. Docking studies were performed at support of the biological data and to elucidate the molecular basis for 5-HT(1A) agonism/antagonism activity.  相似文献   
97.
98.
This systematic review examines critically the scientific basis for Canada's Physical Activity Guide for Healthy Active Living for adults. Particular reference is given to the dose-response relationship between physical activity and premature all-cause mortality and seven chronic diseases (cardiovascular disease, stroke, hypertension, colon cancer, breast cancer, type 2 diabetes (diabetes mellitus) and osteoporosis). The strength of the relationship between physical activity and specific health outcomes is evaluated critically. Literature was obtained through searching electronic databases (e.g., MEDLINE, EMBASE), cross-referencing, and through the authors' knowledge of the area. For inclusion in our systematic review articles must have at least 3 levels of physical activity and the concomitant risk for each chronic disease. The quality of included studies was appraised using a modified Downs and Black tool. Through this search we identified a total of 254 articles that met the eligibility criteria related to premature all-cause mortality (N = 70), cardiovascular disease (N = 49), stroke (N = 25), hypertension (N = 12), colon cancer (N = 33), breast cancer (N = 43), type 2 diabetes (N = 20), and osteoporosis (N = 2). Overall, the current literature supports clearly the dose-response relationship between physical activity and the seven chronic conditions identified. Moreover, higher levels of physical activity reduce the risk for premature all-cause mortality. The current Canadian guidelines appear to be appropriate to reduce the risk for the seven chronic conditions identified above and all-cause mortality.  相似文献   
99.
100.
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