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   1432篇
  免费   128篇
  国内免费   6篇
耳鼻咽喉   16篇
儿科学   52篇
妇产科学   30篇
基础医学   223篇
口腔科学   40篇
临床医学   78篇
内科学   334篇
皮肤病学   12篇
神经病学   156篇
特种医学   61篇
外科学   233篇
综合类   44篇
一般理论   1篇
预防医学   57篇
眼科学   33篇
药学   97篇
中国医学   4篇
肿瘤学   95篇
  2023年   16篇
  2022年   28篇
  2021年   62篇
  2020年   24篇
  2019年   43篇
  2018年   40篇
  2017年   33篇
  2016年   60篇
  2015年   56篇
  2014年   61篇
  2013年   75篇
  2012年   114篇
  2011年   109篇
  2010年   55篇
  2009年   60篇
  2008年   90篇
  2007年   102篇
  2006年   75篇
  2005年   77篇
  2004年   63篇
  2003年   47篇
  2002年   40篇
  2001年   32篇
  2000年   24篇
  1999年   21篇
  1998年   12篇
  1997年   10篇
  1996年   9篇
  1995年   12篇
  1994年   6篇
  1992年   5篇
  1991年   16篇
  1990年   8篇
  1989年   4篇
  1988年   3篇
  1987年   9篇
  1986年   5篇
  1985年   3篇
  1984年   9篇
  1983年   3篇
  1982年   3篇
  1979年   4篇
  1975年   3篇
  1974年   3篇
  1968年   3篇
  1967年   2篇
  1966年   2篇
  1965年   3篇
  1946年   3篇
  1945年   2篇
排序方式: 共有1566条查询结果,搜索用时 15 毫秒
11.
12.
Amyloid beta-peptide (Abeta), the major constituent in senile plaques in Alzheimer's disease (AD) brain, is thought by many researchers to be central to neurotoxicity in AD brain. Increasing evidence from many laboratories indicates that AD brain is under oxidative stress, with strong evidence of protein oxidation, lipid peroxidation, and peroxynitrite damage. A link between the central role of Abeta and oxidative stress in AD brain may be Abeta-associated free radical oxidative stress. If so, antioxidants such as vitamin E should modulate Abeta-induced oxidative damage and neurotoxicity in brain cells. This review summarizes studies of Abeta-associated free radical oxidative stress and its inhibition by vitamin E in cortical synaptosomal membranes and hippocampal neuronal cells in culture. Taken together with the recent report that vitamin E slows the progression of AD, this review strongly supports a central role of Abeta-associated free radical oxidative stress in neurotoxicity in AD brain.  相似文献   
13.
Primary liposarcoma of the orbit is a rare tumour. There are very few cases of orbital liposarcoma reported in the literature, mostly of the myxoid variety. In this paper, the authors report the clinical presentation, histopathological features, results of diagnostic studies and management of a case of orbital low grade myxoliposarcoma with local recurrence, together with a review of the literature.  相似文献   
14.
Studies of preemptive analgesia in humans have shown conflicting results. The study design, patient population and the duration of assessment of postoperative pain are important in the evaluation of preemptive analgesia. We carried out a prospective, randomized, double-blind controlled study in 80 patients of physical status ASA 1-3 undergoing upper abdominal and thoracic surgery. Patients received two epidural injections, one 20 minutes before induction and the other at the end of surgery. Study solution was either morphine (50 micrograms/kg), with or without 0.1% bupivacaine in 10 ml of normal saline, or normal saline alone. The study groups (Pre M, Pre MB) were given either morphine or morphine-bupivacaine before induction and saline at the end of surgery. The control groups (Post M, Post MB) were given saline before induction and morphine or morphine-bupivacaine at the end of surgery. Postoperative pain was assessed with a Visual Analogue Scale (VAS) during coughing and deep breathing at six-hourly intervals for five days. Epidural morphine was given if the VAS exceeded 4. Pre MB compared to Post MB had a significantly increased interval between the analgesic top-ups (P < 0.01) and decreased total postoperative morphine requirements (P < 0.0001) and number of top-ups (P < 0.001). Pre M and Post M were comparable. Pre MB compared to Pre M had significantly decreased total postoperative morphine requirements (P < 0.0001) and number of top-ups (P < 0.0001). Epidural morphine plus bupivacaine is effective as a preemptive analgesic. Morphine plus bupivacaine has better efficacy than morphine given alone before the induction of anaesthesia.  相似文献   
15.
Over a period of 15 months, 11 patients with phaeochromocytoma underwent retroperitoneoscopic excision of their tumours. Five patients had bilateral tumours. All patients underwent thorough preoperative evaluation and preparation with alpha- and beta-blockade. In the majority of the patients a hypertensive response was seen during generation of pneumoretroperitoneum. However, the period of tumour dissection and excision was devoid of large haemodynamic fluctuations. The average time taken was 3.5 to 4 hours per gland. Blood loss in successful laparoscopic excision averaged 240 ml (range 120 to 700 ml). In these patients satisfactory postoperative analgesia could be provided with intramuscular pethidine or intramuscular diclofenac sodium. In three patients the procedure had to be converted to open laparotomy due to haemorrhage. All three patients had preoperative radiological evidence of inferior vena cava and aortic involvement. Patient selection plays an important role in a successful outcome.  相似文献   
16.
PURPOSE: The aim of this study was to assess the efficacy of portoenterostomy in biliary atresia and determine factors that predict outcomes. METHODS: The outcomes after portoenterostomy for biliary atresia from 1976 to 1996 were graded into 3 defined groups: G (good, jaundice free); I (intermediate, progressive liver disease with liver transplant if needed after 3 years of age); P (poor, liver transplant or death at less than 3 years of age). RESULTS: Twenty-seven of 49 children (55%) who underwent portoenterostomy responded. Of these, 13 (26%) were jaundice free (G). Of 14 children (28%) in I, 6 underwent liver transplant after 3 years of age. Of 22 children (44.8%) in P, 14 (28%) died before 3 years and 8 underwent liver transplant before 3 years. Thus, 42% of the children in this series are surviving with native liver. Age at operation in P was significantly different compared with G. Preoperative values of bilirubin and alanine transaminase were comparable in the 3 groups. Postoperative values of bilirubin and alanine transaminase were lower in G and I compared with P Complications were significantly lower in group G. CONCLUSIONS: Portoenterostomy alone in biliary atresia is beneficial in 40% of cases. Factors associated with the outcome include age at operation, postoperative cholangitis, and change in values of bilirubin and alanine transaminase. A classification based on decline of bilirubin and enzyme levels 3 months after portoenterostomy is proposed to predict the long-term outcome of an individual case of biliary atresia. It is particularly relevant in the intermediate group in which timing of referral may preclude or compromise liver transplant.  相似文献   
17.
Objectives: To determine the quality of life (QOL) after stapes surgery and whether audiological parameters for hearing correlate with specific QOL factors. Design: A retrospective cross‐sectional study. Setting: A tertiary referral centre. Participants: A series of 35 patients who underwent stapes surgery of which three were excluded because they were <18 years of age, chronically or mentally ill, or in a dependant relationship. Response rate was 93% (30/32). Nine were further excluded because they had revision or bilateral surgery, or missing data. Twenty‐one patients were included in this study. Main outcome measures: The Glasgow Benefit Inventory (GBI) was used to evaluate general QOL and the Hearing Disability and Handicap Scale (HDHS) was used as a disease‐specific measure. The Belfast Rule of Thumb and Glasgow Benefit Plot assessed hearing outcomes. Results: Operative success was 86% using the Belfast Rule of Thumb and 95% had closure of the air–bone gap to within 20 dB. 81.8% of patients reported a better overall QOL as surgery. Glasgow Benefit Inventory Social and GBI Physical scores correlated positively with the HDHS speech component (P < 0.05). The duration of hearing loss correlated inversely with the average HDHS score (P < 0.05). Conclusion: The majority of patients report a better QOL as undergoing stapes surgery. Speech impacts on people's physical and social QOL of patients. Quality of life tools, in addition to objective audiologic measurements can provide clinicians with patients’ subjective perspective that helps guide clinical decision‐making and counselling.  相似文献   
18.
19.
Foot‐and‐mouth disease (FMD) is endemic in India and causes severe economic loss. Status of FMD in the country for five fiscal years is presented. Outbreaks were more in number in 2007–2008 than 2010–2011. Three serotypes of FMD virus (O, A and Asia1) are prevalent. Serotype O was responsible for 80% of the confirmed outbreaks/cases, whereas Asia1 and A caused 12% and 8%, respectively. Geographical region‐wise assessment indicated varying prevalence rate in different regions viz; 43% in Eastern region, 31.5% in Southern region, 11.6% in North‐eastern region, 5% Central region, 4.4% Western region and 4% in Northern region. Highest number of outbreaks/cases was recorded in the month of September and lowest in June. Emergence and re‐emergence of different genotypes/lineages within the serotypes were evident in real‐time investigation carried out from time to time. Continues antigenic divergence in serotype A resulted in change in the vaccine strain in 2009. As on date, all genetic diversity within the serotypes is well tolerated by the vaccine strains. Unrestricted animal movements in the country play a major role in the spread of FMD.  相似文献   
20.
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