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   26835篇
  免费   2824篇
  国内免费   41篇
耳鼻咽喉   334篇
儿科学   824篇
妇产科学   517篇
基础医学   3577篇
口腔科学   561篇
临床医学   3189篇
内科学   4683篇
皮肤病学   265篇
神经病学   2893篇
特种医学   927篇
外科学   4230篇
综合类   683篇
一般理论   5篇
预防医学   2978篇
眼科学   521篇
药学   1699篇
中国医学   12篇
肿瘤学   1802篇
  2021年   353篇
  2020年   217篇
  2019年   402篇
  2018年   493篇
  2017年   343篇
  2016年   348篇
  2015年   423篇
  2014年   587篇
  2013年   962篇
  2012年   1324篇
  2011年   1280篇
  2010年   725篇
  2009年   704篇
  2008年   1204篇
  2007年   1171篇
  2006年   1147篇
  2005年   1066篇
  2004年   1100篇
  2003年   1047篇
  2002年   899篇
  2001年   885篇
  2000年   922篇
  1999年   744篇
  1998年   340篇
  1997年   301篇
  1996年   320篇
  1995年   297篇
  1994年   258篇
  1993年   289篇
  1992年   638篇
  1991年   620篇
  1990年   589篇
  1989年   607篇
  1988年   571篇
  1987年   595篇
  1986年   522篇
  1985年   524篇
  1984年   395篇
  1983年   344篇
  1982年   239篇
  1981年   212篇
  1980年   202篇
  1979年   364篇
  1978年   201篇
  1977年   204篇
  1976年   227篇
  1975年   181篇
  1974年   240篇
  1973年   228篇
  1972年   187篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
12.
13.
Objective: To examine (i) the associations between physical activity dimensions, cardiorespiratory fitness and body composition and, (ii) the associations between physical activity dimensions, cardiorespiratory fitness, body composition and biomarkers of cardiometabolic health in persons with spinal cord injury (SCI).

Methods: A cross-sectional prospective cohort study with 7-day follow-up was conducted. Body composition, cardiorespiratory fitness and biomarkers of cardiometabolic health were measured in thirty-three participants with SCI (> 1 year post injury). Physical activity dimensions were objectively assessed over 7-days.

Results: Activity energy expenditure (r =.43), physical activity level (r =.39), and moderate-to-vigorous physical activity (MVPA) (r =.48) were significantly (P < 0.001) associated with absolute (L/min) peak oxygen uptake (?O2 peak). ?O2 peak was significantly higher in persons performing ≥150 MVPA minutes/week compared to <40 minutes/week (P?=?0.003). Individual physical activity dimensions were not significantly associated with biomarkers of cardiometabolic health. However, body composition characteristics (BMI, waist and hip circumference) showed significant (P < 0.04), moderate (r >.30) associations with parameters of metabolic regulation, lipid profiles and inflammatory biomarkers. Relative ?O2 peak (ml/kg/min) was moderately associated with only insulin sensitivity (r?=?0.37, P?=?0.03).

Conclusions: Physical activity dimensions are associated with cardiorespiratory fitness; however, stronger and more consistent associations suggest that poor cardiometabolic health is associated with higher body fat content. Given these findings, the regulation of energy balance should be an important consideration for researchers and clinicians looking to improve cardiometabolic health in persons with SCI.  相似文献   

14.
15.
BACKGROUND: Repairing dorsal nasal defects is a frequent challenge for dermatologic surgeons, mainly due to the high frequency of basal cell carcinomas on this site. Obvious scars, mismatched skin and distortion of the nasal contour are the surgical hazards that must be avoided in these cases. AIM: Our aim was to perform surgery involving a simple flap in order to repair medium to large defects on the dorsal side of the nose. METHODS: The dorsal horizontal advancement flap was studied in 12 patients, in order to evaluate the benefits and limits of this surgical procedure. RESULTS: The resulting scars on most of our patients were well-camouflaged among their natural skin lines, and there was neither distortion of the alar contour nor the nostril. CONCLUSIONS: This flap is easy to perform and, in selected cases, provides an outstanding alternative to second-intention healing, full-thickness skin grafts, transposition, rotation and pedicle flaps.  相似文献   
16.
17.
On the Bubble     
Thompson  Don 《JAMA》2006,296(14):1698
  相似文献   
18.
Choristomas, masses of normal tissues in aberrant locations, contain smooth muscle fibers and fibrous tissues. We describe the MR imaging features of two choristomas located in the internal auditory canals and arising from the facial and vestibulocochlear nerves. Both lesions enhanced with contrast material. In one case, enhancement was seen in the geniculate ganglion and greater superficial petrosal nerve. In the other, a medial component enhanced less than the lateral component did.  相似文献   
19.
Bombesin improves survival from methotrexate-induced enterocolitis.   总被引:5,自引:0,他引:5       下载免费PDF全文
OBJECTIVE: The authors determined whether bombesin could improve survival from methotrexate (MTX)-induced enterocolitis. SUMMARY BACKGROUND DATA: Bombesin prevents gut mucosal atrophy, which is produced by feeding rats an elemental diet. Administration of MTX produces a lethal enterocolitis in rats fed an elemental diet. METHODS: On treatment day 0, 60 rats were divided randomly into three groups and fed an elemental diet (Vivonex TEN, Sandoz, Minneapolis, MN) as the only source of nutrition. Groups were subdivided further to receive either saline or bombesin (10 micrograms/kg, subcutaneously, three times a day) beginning either on day 0 or day 14. Methotrexate (20 mg/kg, intraperitoneally) was given to all rats 14 days after the start of an elemental diet. RESULTS: Bombesin prevented the mucosal atrophy in the ileum produced by the elemental diet and significantly decreased mortality in rats given MTX (whether given as a pretreatment or at the time of MTX administration). CONCLUSION: Bombesin significantly improved survival in a lethal model of MTX-induced enterocolitis, possibly by maintaining gut mucosal structure. Administration of bombesin to patients receiving chemotherapy may be clinically useful in preventing the severe enterocolitis induced by various chemotherapeutic agents.  相似文献   
20.
We used vitreous surgery to remove idiopathic epiretinal membranes from the macular area in 70 consecutive cases. The abnormal tissue was successfully removed in each case. Vision improved postoperatively in 61 eyes (87%), remained unchanged in six eyes (9%), and worsened in three eyes (4%). However, at the time of final examination vision was improved in only 47 eyes (67%), primarily because of the occurrence or progression of nuclear sclerosis, which occurred in 38 of 60 phakic eyes (63%). Four preoperative factors were associated with final visual acuity of 20/60 or better: (1) initial vision of 20/100 or better, (2) shorter preoperative duration of blurred vision, (3) thin epiretinal membrane, and (4) absence of traction retinal detachment.  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