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   7555篇
  免费   393篇
  国内免费   72篇
耳鼻咽喉   74篇
儿科学   139篇
妇产科学   80篇
基础医学   870篇
口腔科学   162篇
临床医学   433篇
内科学   1908篇
皮肤病学   416篇
神经病学   471篇
特种医学   319篇
外科学   1718篇
综合类   33篇
预防医学   211篇
眼科学   152篇
药学   299篇
中国医学   19篇
肿瘤学   716篇
  2023年   51篇
  2022年   116篇
  2021年   207篇
  2020年   122篇
  2019年   134篇
  2018年   199篇
  2017年   136篇
  2016年   164篇
  2015年   203篇
  2014年   244篇
  2013年   284篇
  2012年   453篇
  2011年   460篇
  2010年   253篇
  2009年   231篇
  2008年   389篇
  2007年   411篇
  2006年   404篇
  2005年   383篇
  2004年   358篇
  2003年   407篇
  2002年   373篇
  2001年   158篇
  2000年   142篇
  1999年   140篇
  1998年   100篇
  1997年   82篇
  1996年   79篇
  1995年   59篇
  1994年   86篇
  1993年   52篇
  1992年   112篇
  1991年   105篇
  1990年   94篇
  1989年   102篇
  1988年   98篇
  1987年   69篇
  1986年   81篇
  1985年   72篇
  1984年   39篇
  1983年   31篇
  1982年   25篇
  1980年   20篇
  1979年   37篇
  1977年   23篇
  1974年   25篇
  1972年   18篇
  1971年   25篇
  1969年   18篇
  1968年   18篇
排序方式: 共有8020条查询结果,搜索用时 15 毫秒
991.
Transarterial internal radiation with I-131 Lipiodol (TAIR) was performed in 21 patients with multifocal hepatic carcinoma. Eight patients were treated by TAIR alone and 13 by combination of TAIR and intraarterial infusion ofcis-diamminedichloroplatinum (CDDP) and/or adriamycin mitomycin C oil suspension (ADMOS). TAIR was found effective immediately and long-term. Serum α-fetoprotein (AFP) levels dropped to 50% or less in 7 of 14 patients. Eleven of 21 patients (52%) showed 50% or greater decrease in tumor size. The overall 1-year survival rate was 43% and 67% in patients who received 50 Gy or greater tumor dose. Lipiodol distribution pattern of the tumor indicated some difference in the prognosis between the scattered pattern and solid pattern. The solid pattern showed a statistically significant better survival rate. Patients treated with TAIR alone versus those treated with TAIR and chemotherapy showed no difference in their survival rate.  相似文献   
992.
Simultaneous minimally invasive direct coronary artery bypass and abdominal aortic aneurysm repair were conducted in a 66-year-old man uneventful, requiring no transfusion. Surgery required 9 hours and 2 minutes. The tracheal tube was extubated in the operating room. Postoperative bleeding was 215 ml. The postoperative course was very smooth, with the patient able to walk on postoperative day 1. Postoperative coronary arteriogram and aortogram showed favorable results and the patient was discharged on day 23 after surgery.  相似文献   
993.
We assessed the bone status of preterm and term infants by measuring their bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA). Thirty neonates weighing 699–3590 g were selected as subjects. Infants with multiple anomalies or severe chronic lung disease were excluded. Using the corrected term age (35–48 weeks), we measured their lumbar spinal BMD (L1–L4) by DXA. Alkaline phosphatase (ALP) and skeletal alkaline phosphatase (B-ALP) were measured at the same time. In addition, we compared the BMD values with growth parameters and chemical markers. The term BMD correlated significantly with the birth weight (r = .90), height (r = .85), and gestational age (r = .76). The birth weight correlated more closely with the BMD than with the weight at the time of BMD measurement. The B-ALP level showed an inverse correlation with BMD (r = −0.41). The preterm infants apparently acquired lower BMDs during intrauterine life. The inverse correlation of B-ALP with BMD may be found only in the neonatal period. The BMD measured by DXA and the B-ALP level are very useful parameters for assessing bone status in infants, including extremely low birth weight infants. Received: Aug. 21, 1997 / Accepted: Nov. 6, 1997  相似文献   
994.
995.
We investigated the changes of natural type of interferon-α (IFNα) on calcium and bone metabolism in patients with chronic hepatitis C. Natural IFNα was injected intramuscularly at daily doses of 6 million units for 2 weeks to 10 patients with chronic hepatitis caused by hepatitis C virus, and followed by 3-times-a-week administration for another 10 weeks. The markers for bone metabolism including serum bone-Gla protein (BGP) concentration and urinary excretion of pyridinolines (pyridinoline and deoxypyridinoline) were measured before and during the treatment. The twelve-week administration of IFNα reduced pyridinoline excretion from 39.7±13.3 (SD) pmol/μ mol · creatinine to 28.3±8.1 pmol/μ mol · creatinine (p<0.06), and that of deoxypyridinoline from 6.51±3.38 pmol/μ mol · creatinine to 3.91±2.07 pmol/μ mol · creatinine (p<0.01), although serum levels of BGP and parathyroid hormone (PTH) did not show any significant changes. The ratio of BGP/urinary pyridinoline increased from 0.098±0.074 to 0.198±0.093 at the end of 12th week (p<0.03), and that of BGP/deoxypyridinoline increased from 0.630±0.502 to 1.550±0.788 at 12th week (p<0.02). Serum aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP) did not change significantly during the study. IFNα reduces bone resorption in contrast with insignificant effects on bone formation in patients with mild to moderate hepatitis. The effects on calcium and bone metabolism may give beneficial effects for patients with high turnover osteoporosis.  相似文献   
996.
The effects of psoriatic sera were investigated on the generation of oxygen intermediates (OIs) by normal polymorphonuclear leucocytes (PMNs). Although increased superoxide generation was noted, a further respiratory burst of the PMns was significantly suppressed. Since superoxide dismutase (SOD) and catalase activities of the sera assayed in the xanthine-xanthine oxidase system were comparable to the controls, it still remains obscure why this dissociation occurs. It is suggested that increased generation of superoxide anion from the PMNs may be another facet of PMN activation which plays an important role in the psoriatic process.  相似文献   
997.
N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) dissolved indistilledwater (5 g/1) was administered orally once by gastrictube ata dose of 0.25 ml/10 g body weight to 5-day-old or 28-day-oldWistar Furth (W/Fu) or ACI rats. Gastric tumorsin the glandularstomach were found in 58% of 5-day-old ACI rats, but none werefound in the rest of the groups. Forestomach tumors were foundin both strains of rats at bothage groups with incidences of68–100%. Lung tumors wereinduced in 64% of 5-day-old and6% of 28-day-old W/Fu rats,but not in ACI rats. Besides thetumors, a high frequency of hepatic cysts was also noted inACI rats. Intestinal metaplastic foci with alkaline phosphataseactivity were foundin the group of 5-day-old ACI rats and nonein the rest ofthe groups. The results showed that the incidencesand thelocations of tumors in rats induced by MNNG are greatlyinfluencedby both strain and age.  相似文献   
998.
999.
A method of assessing “atherosclerosis”, if used according to certain rules, was shown in an earlier study to be capable of discriminating between groups of aortas or coronary arteries according to the quantity of certain defined lesions. It would not measure absolute amounts, but would show whether one group of specimens had more or less of the factor assessed than another and would indicate the statistical significance of this finding according to the number of specimens in each group.  相似文献   
1000.
We have developed a method that allows us to place regions of interest on X-ray CT (XCT) images that are automatically adjusted to positron emission tomography (PET) images from the same patient. A face mask with landmarks was used during PET and XCT studies for matching slice positions between PET and XCT. Anatomical locations in different images of the same slice can be accurately adjusted using the landmarks and a video system. In our clinical experience misadjustments of the slice position are on the average less than 2 mm in axial distance and 1.0 degrees in slice angle. The method is easily applicable to any PET or XCT device.  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