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   29713篇
  免费   1888篇
  国内免费   180篇
耳鼻咽喉   473篇
儿科学   924篇
妇产科学   854篇
基础医学   3150篇
口腔科学   857篇
临床医学   2466篇
内科学   6512篇
皮肤病学   617篇
神经病学   1384篇
特种医学   987篇
外国民族医学   10篇
外科学   5126篇
综合类   832篇
现状与发展   1篇
一般理论   34篇
预防医学   2008篇
眼科学   805篇
药学   2629篇
  1篇
中国医学   195篇
肿瘤学   1916篇
  2023年   400篇
  2022年   1186篇
  2021年   1651篇
  2020年   874篇
  2019年   1137篇
  2018年   1458篇
  2017年   904篇
  2016年   944篇
  2015年   1057篇
  2014年   1340篇
  2013年   1631篇
  2012年   2235篇
  2011年   2302篇
  2010年   1198篇
  2009年   946篇
  2008年   1437篇
  2007年   1506篇
  2006年   1355篇
  2005年   1161篇
  2004年   1092篇
  2003年   965篇
  2002年   868篇
  2001年   445篇
  2000年   425篇
  1999年   384篇
  1998年   197篇
  1997年   138篇
  1996年   125篇
  1995年   131篇
  1994年   96篇
  1993年   77篇
  1992年   173篇
  1991年   158篇
  1990年   163篇
  1989年   135篇
  1988年   127篇
  1987年   117篇
  1986年   124篇
  1985年   113篇
  1984年   89篇
  1983年   111篇
  1982年   57篇
  1981年   54篇
  1979年   94篇
  1978年   64篇
  1977年   68篇
  1976年   60篇
  1975年   54篇
  1974年   52篇
  1973年   42篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
22.
A 24-year-old man presented with a 24-hour history of pain and numbness in his left arm. The patient's clinical presentation of peripheral embolism was corroborated by angiography. Echocardiographic study showed masses in both right and left atria. Pathologic specimen from the embolus confirmed the diagnosis of aspergillosis.  相似文献   
23.
Abstract Simultaneous bilateral avulsions of the tibial tuberosity are rare injuries. The authors found only five reported cases in the orthopedic literature. We add a further case of bilateral avulsions of the tibial tuberosity with the longest reported follow-up.  相似文献   
24.
25.
26.
This prospective study contains clinical and experimental parts. In the clinical study, 125 patients given intramuscular chloroquine for malaria were followed for 2 months in order to detect local injection site complications. Adequate local antiseptic conditions were ensured before giving the injection. Twenty-three patients (18.4%) had minimal local reaction in the form of redness, induration and/or a lump. No pyogenic abscess was noted in contrast to a previous report. In the second part of the study, an experimental animal (Green monkey) was given either chloroquine phosphate, Ampiclox or normal saline intramuscularly. The injection site was later biopsied and histologically examined. Intramuscular chloroquine was found to cause severe inflammatory reactions and muscle necrosis, whereas other injections had very minimal local effects. It is concluded that intramuscular chloroquine causes muscle necrosis which may lead to acute pyogenic abscess if minimal contamination takes place.  相似文献   
27.
The role of the IGFs and IGFBPs on age-related changes in BMD in adult men and women is not well understood. Studying an age-stratified community based sample of 344 men and 276 women, we found higher IGFBP-2 levels to be associated with lower BMD. IGFBP-2, which increases with age in both men and women, was the strongest, most consistent predictor of BMD among the IGF/IGFBPs studied. INTRODUCTION: Insulin-like growth factors (IGFs) and their binding proteins (IGFBPs) are important regulators of tissue growth and metabolism, but their association with BMD in adult men and women is controversial. MATERIALS AND METHODS: In an age-stratified, random sample of the community population, we examined the role of serum levels of IGF-I, IGF-II, and IGFBP-1, -2, and -3 on BMD of the proximal femur (total hip), lateral spine, midshaft, and ultradistal radius as measured by DXA. We explored the association before and after adjustment for potential confounders, including age, bioavailable estradiol and testosterone, sex hormone binding globulin (SHBG), and measures of total fat and skeletal muscle mass. RESULTS: We studied 344 men (age, 23-90 years) and 276 women (age, 21-93 years; 166 postmenopausal) not on hormone replacement or oral contraceptives. In both men and women, IGF-I and IGFBP-3 levels fell with advancing age, whereas IGFBP-2 levels tended to rise with age. There was an inverse association of IGFBP-2 with BMD at most skeletal sites in men and both premenopausal and postmenopausal women, whereas lower IGF-I and IGFBP-3 were associated with lower BMD in men and postmenopausal women only. Lower IGF-II was associated with lower BMD in men only. There were no associations between IGFBP-1 and BMD in either sex. After adjustment for age, in most cases, we found no further associations between IGF-I, IGF-II, or IGFBP-3 and BMD. In contrast, after age adjustment, higher IGFBP-2 remained a predictor of lower BMD in men and postmenopausal women at all sites except for the lateral spine (for men: r = -0.21, -0.20, and -0.19, all p < 0.001; and for postmenopausal women: r = -0.34, -0.24, and -0.25, all p < 0.01, for the total hip, midshaft, and ultradistal radius, respectively). IGFBP-2 remained an independent negative predictor of BMD in men, postmenopausal women, and all women combined after additional adjustment for bioavailable sex steroids, but not at all sites after adjustment for SHBG and muscle mass. In premenopausal women, IGFBP-2 had similar associations as seen in postmenopausal women, but they were weaker and not statistically robust. CONCLUSIONS: Among the IGF/IGFBPs in our study, IGFBP-2 was a key negative predictor of BMD among men and women, particularly postmenopausal women. Our findings suggest a potential role of the IGF/IGFBP system in regulating bone loss in aging men and women and identify a previously under-recognized, potentially deleterious role for IGFBP-2, a known inhibitor of IGF action that increases with age in both sexes. Whether the action of the IGF/IGFBP system on bone metabolism is mediated partly through its effects on muscle mass or SHBG deserves further study.  相似文献   
28.
Ultrasound registration of the bone surface for surgical navigation.   总被引:4,自引:0,他引:4  
OBJECTIVE: To allow non-invasive registration of the bone surface for computer-assisted surgery (CAS), this investigation reports the development and evaluation of intraoperative registration using 2D ultrasound (US) images. This approach employs automatic segmentation of the bone surface reflection from US images tagged with the 3D position to enable the application of CAS to minimally invasive procedures. METHODS: The US-based registration method was evaluated in comparison to point-based registration, which is the predominant method in current clinical use. The absolute accuracy of the US-based registration was determined using a phantom pelvis, with fiducial registration providing the ground truth. The relative accuracy was determined by an intraoperative study comparing the US registration to the point-based registration obtained as part of the HipNav experimental protocol. RESULTS: The phantom pelvis study demonstrated equivalent accuracy between point- and US-based registration under in vitro conditions. In the intraoperative study, the US-based registration was sufficiently consistent with the point-based registration to warrant larger-scale clinical trials of this non-invasive registration method. CONCLUSION: Ultrasound-based registration eliminates the need for physical contact with the bone surface as in point-based registration. As a result, non-invasive registration could fully unlock the potential of computer-assisted surgery, enabling development of the next generation of minimally invasive surgical procedures.  相似文献   
29.
30.
In this report we describe, herewith, a patient with primary pigmentary dystrophy of the retina (retinitis pigmentosa) associated with unilateral retinal arteriovenous communication and exudative retinal detachment. The patient had complete resolution of the retinal detachment following laser photocoagulation treatment. Such association has not been previously reported.  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