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   1893篇
  免费   109篇
  国内免费   12篇
耳鼻咽喉   7篇
儿科学   35篇
妇产科学   50篇
基础医学   207篇
口腔科学   41篇
临床医学   141篇
内科学   445篇
皮肤病学   58篇
神经病学   95篇
特种医学   29篇
外科学   351篇
综合类   49篇
预防医学   188篇
眼科学   37篇
药学   180篇
中国医学   6篇
肿瘤学   95篇
  2024年   4篇
  2023年   25篇
  2022年   13篇
  2021年   113篇
  2020年   63篇
  2019年   77篇
  2018年   95篇
  2017年   64篇
  2016年   58篇
  2015年   54篇
  2014年   94篇
  2013年   91篇
  2012年   142篇
  2011年   149篇
  2010年   113篇
  2009年   73篇
  2008年   74篇
  2007年   102篇
  2006年   74篇
  2005年   96篇
  2004年   77篇
  2003年   69篇
  2002年   39篇
  2001年   27篇
  2000年   14篇
  1999年   18篇
  1998年   5篇
  1997年   11篇
  1996年   4篇
  1994年   6篇
  1992年   8篇
  1991年   18篇
  1990年   7篇
  1989年   9篇
  1988年   10篇
  1987年   7篇
  1986年   13篇
  1985年   6篇
  1983年   4篇
  1979年   3篇
  1977年   8篇
  1974年   4篇
  1973年   12篇
  1972年   16篇
  1971年   10篇
  1970年   3篇
  1969年   5篇
  1968年   5篇
  1967年   6篇
  1966年   3篇
排序方式: 共有2014条查询结果,搜索用时 312 毫秒
1.
We report an index case of a male patient who presented with all clinical manifestations of Pacak‐Zhuang syndrome, including early‐age polycythemia, multiple pheochromocytomas/paragangliomas, duodenal somatostatinoma, and ocular findings. Sequencing analysis detected an EPAS1 mutation in all tumors tested, but not in the germline.  相似文献   
2.
3.
4.
Objective: To identify factors that affect operative mortality and morbidity and long-term survival after completion pneumonectomy. Methods: We retrospectively reviewed the charts of consecutive patients who underwent completion pneumonectomy at our cardiothoracic surgery department from January 1996 to December 2005. Results: We identified 69 patients, who accounted for 17.8% of all pneumonectomies during the study period; 22 had benign disease and 47 malignant disease (second primary lung cancer, n = 19; local recurrence, n = 17; or metastasis, n = 11). There were 50 males and 19 females with a mean age of 60 years (range, 29–80 years). Postoperative mortality was 12% and postoperative morbidity 41%. Factors associated with postoperative mortality included obesity (p = 0.005), coronary artery disease (p = 0.03), removal of the right lung (p = 0.02), advanced age (p = 0.02), and renal failure (p < 0.0001). Preoperative renal failure was the only significant risk factor for mortality by multivariate analysis (p = 0.036). Bronchopleural fistula developed in seven patients (10%), with risk factors being removal of the right lung (p = 0.04) and mechanical stump closure (p = 0.03). Overall survival was 65% after 3 years and 46% after 5 years. Long-term survival was not affected by the reason for completion pneumonectomy. Conclusion: Although long-term survival was acceptable, postoperative mortality and morbidity rates remained high, confirming the reputation of completion pneumonectomy as a challenging procedure. Significant comorbidities and removal of the right lung were the main risk factors for postoperative mortality. Improved patient selection and better management of preoperative renal failure may improve the postoperative outcomes of this procedure, which offers a chance for prolonged survival.  相似文献   
5.
PURPOSE: Controlling the cerebral and systemic hemodynamic responses to laryngoscopy and tracheal intubation may play a role in determining clinical outcome in pediatric neurosurgical patients. This study compared the effects of remifentanil and fentanyl on cerebral blood flow velocity (CBFV) and hemodynamic profile during laryngoscopy and tracheal intubation in children under sevoflurane anesthesia. METHODS: Sixty healthy children aged two to six years undergoing dental surgery under general anesthesia were enrolled. Each child was randomly assigned to receive a remifentanil or fentanyl infusion, at a rate of 0.75, 1.0, or 1.5 microg x kg(-1) x min(-1) after induction of anesthesia with 2% sevoflurane. Middle cerebral artery blood flow velocity was measured by transcranial Doppler (TCD) sonography. Once a baseline set of hemodynamic variables and TCD measurements were recorded, the opioid infusion was started. Measurements were taken at two-minute intervals, starting four minutes prior to laryngoscopy until four minutes following naso-tracheal intubation. RESULTS: Remifentanil caused a more significant decrease in mean arterial pressure and CBFV prior to tracheal intubation than did fentanyl (P < 0.001). During laryngoscopy and for two minutes following tracheal intubation, CBFV increased in all remifentanil groups (P < 0.05), whereas it remained stable in all fentanyl groups. CONCLUSION: This study suggests that fentanyl was more effective than remifentanil at preventing increases in CBFV during and immediately following laryngoscopy and tracheal intubation in children undergoing sevoflurane anesthesia. Fentanyl also seemed to provide a more stable hemodynamic profile prior to laryngoscopy and tracheal intubation when compared to remifentanil.  相似文献   
6.
Geographical variations in the incidence of disease are of considerable theoretical and practical importance. It has been claimed that the distribution of acute lymphoblastic leukemia (ALL) phenotypes in Saudi Arabia is different from that recorded in the Western literature. One hundred and twelve (112) patients under 15 years of age, diagnosed as ALL between January 1992 and May 1994 had immunophenotypes performed on their blast cells. Common ALL (cALL) together with pre-B-ALL, formed 86.5% of the total; B-cell 3%, T-cell 6% and null cell 4.5%. These figures are not significantly different from the Western literature. A previous claim from this institution in 1990, that both null and B-cell ALL were significantly increased compared with elsewhere, is not supported by the present figures. Age and sex distribution, and FAB classification, L1 77%, L2 20% and L3 3%, were also of the same order as described elsewhere and, in particular, there was no increase in the frequency of L3 subtype.  相似文献   
7.
The etiological role of human papillomavirus (HPV) in esophageal carcinoma (EC) in relation to p53, mdm2, p21(waf), c-erbB2 and the overall survival (OS) rate was investigated. Tumor and normal tissues from 50 EC were evaluated by polymerase chain reaction and InnoLiPA for HPV. Single strand conformation polymorphism/sequencing were used to detect p53 gene mutations. Immunohistochemistry was performed to determine p53, mdm2, p21(waf)and c-erbB2 expression. Human papillomavirus was detected in 54% of tumors and in 24% of normal tissues. p53, mdm2 and c-erbB2 overexpression was detected in 68%, 70% and 60% of tumors and in 14%, 16% and 10% of normal samples, whereas loss of p21(waf) was evident in 64% of tumors. p53 mutations were detected in 20% of cases. Exon 8 and 5 showed the highest mutation rate (40% each), followed by exons 6 and 7 (10% each). There was a significant correlation between HPV and p53, mdm2, c-erbB2 overexpression. The OS was significantly associated with overexpression of p53 and loss of p21(waf). Human papillomavirus infection is frequent in Egyptian EC. Both p53-dependent and p53-independent pathways seem to be involved in HPV-associated EC. mdm2 and c-erbB2 are possible targets for HPV in the p53-independent pathway. However, only advanced stage and aberrant expression of p53 and p21(waf) are independent prognostic markers.  相似文献   
8.
9.
10.
Phrenic-sparing analgesic techniques for shoulder surgery are desirable. Intra-articular infiltration analgesia is one promising phrenic-sparing modality, but its role remains unclear because of conflicting evidence of analgesic efficacy and theoretical concerns regarding chondrotoxicity. This systematic review and meta-analysis evaluated the benefits and risks of intra-articular infiltration in arthroscopic shoulder surgery compared with systemic analgesia or interscalene brachial plexus block. We sought randomised controlled trials comparing intra-articular infiltration with interscalene brachial plexus block or systemic analgesia (control). Cumulative 24-h postoperative oral morphine equivalent consumption was designated as the primary outcome. Secondary outcomes included visual analogue scale pain scores during the first 24 h postoperatively; time-to-first analgesic request; patient satisfaction; opioid-related side-effects; block-related adverse events; and any indicators of chondrotoxicity. Fifteen trials (863 patients) were included. Compared with control, intra-articular infiltration reduced 24-h postoperative analgesic consumption by a weighted mean difference (95%CI) of −30.9 ([−38.9 to −22.9]; p < 0.001). Intra-articular infiltration also reduced the weighted mean difference (95%CI) pain scores up to 12 h postoperatively, with the greatest reduction at 4 h (−2.2 cm [(−4.4 to −0.04]); p < 0.05). Compared with interscalene brachial plexus block, there was no difference in opioid consumption, but patients receiving interscalene brachial plexus block had better pain scores at 2, 4 and 24 h postoperatively. There was no difference in opioid- or block-related adverse events, and none of the trials reported chondrotoxic effects. Compared with systemic analgesia, intra-articular infiltration provides superior pain control, reduces opioid consumption and enhances patient satisfaction, but it may be inferior to interscalene brachial plexus block patients having arthroscopic shoulder surgery.  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