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   30039篇
  免费   2461篇
  国内免费   105篇
耳鼻咽喉   258篇
儿科学   691篇
妇产科学   518篇
基础医学   4192篇
口腔科学   379篇
临床医学   3268篇
内科学   6516篇
皮肤病学   356篇
神经病学   2749篇
特种医学   974篇
外科学   4888篇
综合类   381篇
现状与发展   1篇
一般理论   27篇
预防医学   2346篇
眼科学   460篇
药学   2189篇
中国医学   47篇
肿瘤学   2365篇
  2023年   268篇
  2022年   475篇
  2021年   1046篇
  2020年   548篇
  2019年   869篇
  2018年   993篇
  2017年   703篇
  2016年   727篇
  2015年   835篇
  2014年   1142篇
  2013年   1451篇
  2012年   2288篇
  2011年   2269篇
  2010年   1232篇
  2009年   1055篇
  2008年   1766篇
  2007年   1787篇
  2006年   1639篇
  2005年   1581篇
  2004年   1504篇
  2003年   1405篇
  2002年   1368篇
  2001年   353篇
  2000年   305篇
  1999年   331篇
  1998年   305篇
  1997年   264篇
  1996年   230篇
  1995年   204篇
  1994年   205篇
  1993年   176篇
  1992年   248篇
  1991年   195篇
  1990年   204篇
  1989年   193篇
  1988年   183篇
  1987年   179篇
  1986年   144篇
  1985年   140篇
  1984年   159篇
  1983年   120篇
  1982年   121篇
  1981年   110篇
  1980年   117篇
  1979年   96篇
  1978年   106篇
  1977年   85篇
  1975年   78篇
  1974年   74篇
  1971年   70篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Aspirin‐exacerbated respiratory disease (AERD) has been recognized in adults with chronic asthma. Samter's triad is a subset of AERD where adult patients develop nasal polyps, asthma, and sensitivity to aspirin. This condition is thought not to occur before the third decade of life. We report a 13‐year‐old boy with nasal polyps who suffered a life‐threatening exacerbation of asthma during a graded aspirin challenge. Resuscitation required positive pressure ventilation and inotropic support. Our observations confirm that classical Samter's triad can occur in children. We suggest that graded aspirin challenges in children are undertaken in a facility with equipment and staff trained for resuscitation. Consideration should be given to this rare complication when prescribing nonsteroidal anti‐inflammatory drugs in the perioperative period. Suspicion of this condition merits referral to an immunologist for desensitization to aspirin.  相似文献   
992.
993.
994.
995.
Aim The study aimed to assess the prevalence and significance of anaemia during long‐course neoadjuvant radiotherapy for rectal cancer at our centre. Method Hospital coding and a prospective oncology database were used to identify all patients undergoing long‐course neoadjuvant radiotherapy for rectal cancer at our centre between 2004 and 2009. A retrospective review of computerized records was used to extract individual patient data. Anaemia was defined as a haemoglobin level of < 11.5 g/dl for women and of < 13 g/dl for men. Downstaging was assessed by comparing radiological stage (rTNM) with histological stage (ypTNM). Tumour regression after radiotherapy was assessed using the Rectal Cancer Regression Group (RCRG) scores of 1–3. The results were analysed using Gnu PSPP statistical software. Results There were 70 patients (51 men) of median age 66 (interquartile range 60–72.75) years. Of these, 24 were anaemic. Two (3%) had no haemoglobin level recorded and were excluded. Forty‐two per cent of anaemic patients demonstrated mural (T) downstaging compared with 68% of nonanaemic patients (P = 0.03). There was no difference in nodal downstaging between the groups. The RCRG scores showed more tumour regression in nonanaemic patients than in anaemic patients, as follows: RCRG 1, 59%vs 30%; RCRG 2, 11%vs 17%; and RCRG 3, 38%vs 46% (P < 0.001). Conclusion The prevalence of anaemia in patients undergoing long‐course neoadjuvant radiotherapy was 35%. Anaemia during long‐course neoadjuvant radiotherapy was associated with significant reductions in tumour downstaging and regression.  相似文献   
996.
997.
Abstract

Pathologic fractures may occur with minimal trauma after spinal cord injury (SCI) because of osteoporosis. Rats were evaluated to determine whether they could be used as an SCI animal model. Male Sprague-Dawley rats underwent spinal cord transection at the ninth thoracic vertebrae. Control rats underwent a sham procedure. Mechanical testing of the humeral shaft, femoral shaft, tibial shaft, femoral neck, distal femur, and proximal tibia was performed separately at 0, 8, and 24 weeks after surgery. At 24 weeks, significant differences between SCI and control rats were found in maximum torque needed to produce failure in the femoral shaft (63 percent of control, p < 0.05) and tibial shaft (63 percent, p < 0.01), and in compressive load to produce failure in cross-sectional specimens of the distal femur (51 percent, p < 0.05) and proximal tibia (50 percent, p < 0.01 ). No differences were found in the maximum torque needed to produce failure of the humeral shaft (106 percent, p = 0.77) between SCI and control rats. Reductions in relative bone strength in SCI rats at 24 weeks were similar in magnitude to bone mineral density changes reported in humans with chronic paraplegia. Thus, Sprague-Dawley rats appear to be good animal models in which to evaluate changes in bone strength following SCI. U Spinal Cord Med 1998; 21:302-308)  相似文献   
998.
Background?Alkaptonuria is a rare single-gene disorder characterized by black pigmentation of cartilage and other connective tissues. Premature degenerative arthritis affects the large joints in many of these of patients. Medical treatment is limited to a protein-restricted diet (phenylalanine and tyrosine) with surgery reserved for end-stage joint disease. As in other metabolic bone diseases, there are concerns about the quality and strength of affected bones and therefore the suitability and longevity of replacement arthroplasty. The histopathology and outcome of joint replacement for alkaptonuric arthritis is unknown and limited to sporadic case reports.Patients and results?We describe 11 joint replacements in 3 patients with alkaptonuric polyarthropathy, including shoulder and elbow replacements not previously reported. No prosthetic failures occurred in up to 12 years of follow-up.Interpretation?Total joint replacement is an acceptable treatment for degenerative joint disease in alkaptonuric patients, with implant survival comparable to that found in patients with osteoarthritis.  相似文献   
999.

Purpose

Children with multiple hereditary exostoses (MHE) have numerous osteochondromas, with the most prominent lesions typically over the appendicular skeleton. A recent report noted a high rate of intracanal lesions in this patient population and recommended preventative spinal screening with magnetic resonance imaging (MRI) or computed tomography (CT). We sought to evaluate the prevalence of spinal stenosis from intracanal osteochondromas at our pediatric orthopedic center in order to evaluate if routine screening is warranted.

Methods

All pediatric patients treated for MHE were retrospectively identified. Records were reviewed to determine demographics, previous orthopedic surgery, and indication and results of axial spine imaging (CT or MRI). Imaging studies were reviewed to evaluate the presence of intracanal and compressive spinal lesions.

Results

Between 1990 and 2011, axial imaging was performed in nine patients with MHE due to concerns of pain, weakness, and/or dizziness. These patients had moderate disease involvement, with a mean of 4.9 previous orthopedic surgeries to address skeletal osteochondromas. Two patients with MHE had cervical spinal stenosis secondary to intracanal osteochondromas. Both children successfully underwent spinal decompression. Thus, of our MHE population undergoing axial imaging, 22 % were noted to have intracanal lesions.

Conclusions

Our experience reveals a >20 % rate of compressive intracanal osteochondromas in MHE patients undergoing spinal imaging. These two patients represent 5 % of the MHE patients treated at our center. These lesions may be slow growing, and significant consequences can occur if not identified promptly. Thus, we confer that routine axial screening of the spinal canal may be warranted in these children.  相似文献   
1000.
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