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   6728篇
  免费   490篇
  国内免费   39篇
耳鼻咽喉   97篇
儿科学   125篇
妇产科学   133篇
基础医学   966篇
口腔科学   552篇
临床医学   549篇
内科学   1460篇
皮肤病学   264篇
神经病学   431篇
特种医学   187篇
外科学   822篇
综合类   51篇
一般理论   3篇
预防医学   584篇
眼科学   155篇
药学   494篇
中国医学   70篇
肿瘤学   314篇
  2023年   56篇
  2022年   70篇
  2021年   195篇
  2020年   100篇
  2019年   147篇
  2018年   303篇
  2017年   222篇
  2016年   261篇
  2015年   329篇
  2014年   326篇
  2013年   459篇
  2012年   609篇
  2011年   577篇
  2010年   379篇
  2009年   316篇
  2008年   391篇
  2007年   359篇
  2006年   366篇
  2005年   295篇
  2004年   244篇
  2003年   205篇
  2002年   147篇
  2001年   80篇
  2000年   99篇
  1999年   79篇
  1998年   47篇
  1997年   56篇
  1996年   54篇
  1995年   39篇
  1994年   28篇
  1993年   24篇
  1992年   31篇
  1991年   34篇
  1990年   36篇
  1989年   32篇
  1988年   21篇
  1987年   23篇
  1986年   17篇
  1985年   12篇
  1984年   16篇
  1983年   11篇
  1975年   9篇
  1971年   8篇
  1970年   8篇
  1968年   8篇
  1959年   9篇
  1958年   17篇
  1957年   9篇
  1956年   9篇
  1954年   9篇
排序方式: 共有7257条查询结果,搜索用时 62 毫秒
1.
2.
IntroductionThis article deals with the occurrence of health problems due to gunshot wounds to the face among military police officers, in the metropolitan region of Rio de Janeiro, who were submitted to surgery at the Oral and Maxillofacial Surgery and Traumatology Clinic of Hospital Central da Polícia Militar.ObjectiveTo identify the profile of patients submitted to surgery as a result of gunshot wounds, the anatomical distribution of maxillofacial fractures, the identified sequelae and complications, the health specialties involved in the rehabilitation of these patients, and to discuss the social, emotional and work performance-related effects of work among these subjects.MethodsA retrospective epidemiological study was carried out based on secondary data from military police officers who were submitted to surgery at Hospital Central da Polícia Militar due to gunshot wounds from June 2003 to December 2017.ResultsDuring the study period, 778 surgeries were performed in the operating room by the Oral and Maxillofacial Surgery and Traumatology service at Hospital Central da Polícia Militar, 186 of which were due to gunshot wounds (23.9%). All patients were males and the mean age 34.7 years. Bone segment loss was the most common sequela. Facial esthetic impairment and reports of insomnia were the most often identified late consequences of impact on health and social life. Regarding the occupational impacts of the sustained injury, the mean time away from work due to medical leave for the treatment of maxillofacial injuries was 11.7 months.ConclusionThe treatment of gunshot wounds patients with facial injuries requires multiple surgical interventions and their rehabilitation requires the involvement of different health specialties. Further studies are needed to qualitatively analyze the impact of this type of facial trauma on the patients' lives and their social consequences.  相似文献   
3.
The outbreaks of rabies in humans transmitted by Desmodus rotundus in 2004 and 2005, in the northeast of the Brazilian State of Para, eastern Amazon basin, made this a priority area for studies on this zoonosis. Given this, the present study provides data on this phenomenon in an urban context, in order to assess the possible circulation of the classic rabies virus (RABV) among bat species in Capanema, a town in the Amazon basin. Bats were collected, in 2011, with mist nets during the wet and dry seasons. Samples of brain tissue and blood were collected for virological and serological survey, respectively. None of the 153 brain tissue samples analyzed tested positive for RABV infection, but 50.34% (95% CI: 45.67-55.01%) of the serum samples analyzed were seropositive. Artibeus planirostris was the most common species, with a high percentage of seropositive individuals (52.46%, 95% CI: 52.31 52.60%). Statistically, equal proportions of seropositive results were obtained in the rainy and dry seasons (c2 = 0.057, d.f. = 1, p = 0.88). Significantly higher proportions of males (55.96%, 95% CI: 48.96-62.96%) and adults (52.37%, 95% CI: 47.35-57.39%) were seropositive. While none of the brain tissue samples tested positive for infection, the high proportion of seropositive specimens indicates that RABV may be widespread in this urban area.  相似文献   
4.
5.
6.
Objectives: Upper gastrointestinal bleeding, particularly from a stress-induced duodenal ulcer, is an extremely important perioperative complication in cardiovascular surgery. Methods: In the present study, 33 patients undergoing elective open heart surgery between July 2000 and February 2001 were allocated to either a famotidine (FAM) or rabeprazole (RPZ) group to examine the perioperative gastric and esophageal pH readings, in conjunction with an investigation into the effect of infection with Helicobacter pylori (HP). Results: Postoperative upper gastrointestinal bleeding did not occur in either group, and the intraoperative and postoperative mean gastric pH readings, as well as the holding time pH> 6, suggested sufficient acid suppression by either drug. Gastric acid secretion was less strongly suppressed in HP-negative patients in the FAM group, but was unaffected by HP infection status in the RPZ group. Conclusion: The FAM group and RPZ group revealed a sufficient effect of gastric acid suppression. It was indicated that FAM had an insufficient effect of gastric acid suppression for HP-negative patients.  相似文献   
7.
Intrahepatic shunt ratio was calculated from the fraction of the uptake constant and the blood background, analyzing the data of 99mTc-(Sn)-N-pyridoxyl-5-methyltryptophan (99mTc-PMT) hepatobiliary imaging by Rutland method. Shunt flow and total hepatic blood flow (THBF) were also calculated from the values for the effective hepatic blood flow (EHBF) estimated from the blood clearance technique. In 15 cases of normal volunteer, the average of the shunt ratio, shunt flow, and THBF were 18.4 +/- 5.4 (S.D.)%, 137.8 +/- 49 ml/min, and 753 +/- 83.2 ml/min, respectively. In 8 cases of chronic hepatitis, the values were 35.2 +/- 2.6%, 276 +/- 55.4 ml/min, and 794.1 +/- 119.4 ml/min, respectively. In 12 cases of liver cirrhosis, the values were 51.4 +/- 12.6%, 353.9 +/- 141.3 ml/min, and 685.6 +/- 174.8 ml/min, respectively. In cases of chronic hepatitis and liver cirrhosis, in comparison with normal cases, the values for the shunt ratio and shunt flow were significantly increased (p less than 0.001) and those for EHBF were significantly decreased (p less than 0.001), but those for THBF were not significantly altered. There was a significant inverse correlation between the shunt ratio and EHBF (r = -0.842) in all 35 cases. This method is considered to be useful for differential diagnosis, estimation of the grade of the diseases, and evaluation of pathophysiology of various diffuse liver diseases.  相似文献   
8.
AIM: To evaluate the cause of elevated prostate-specific antigen (PSA) in patients with transrectal needle biopsy negative for prostate cancer. METHODS: Serum PSA concentration, prostate volume, and pathologic findings were examined in 223 patients with negative biopsy for prostate cancer. The degree of prostate inflammation was determined by the extent and degree of inflammation shown by biopsy specimens and is expressed as an inflammation score (range: 0-36). RESULTS: A significant correlation was found between PSA concentration and prostate total volume (P=0.0001). Prostate chronic inflammation showed no correlation with PSA concentration (P=0.485, F=0.488). After allocating patients to normal PSA (4 ng/mL) groups, we found that serum PSA concentrations in both groups were predominantly affected by prostate total volume. CONCLUSIONS: An increase in prostate volume appears to be the major contributor to a high serum PSA concentration in patients with negative biopsy for prostate cancer. However, in contrast to previous reports, there was no correlation between the degree of prostate chronic inflammation and serum PSA concentrations.  相似文献   
9.
Tracking performance was investigated in normal and clumsy children in two age-groups, six to seven and 10 to 11 years. Target signals moving unpredictably along a straight line had to be tracked, both with and without visual feedback. Performance was described in three ways: (1) performance in the low-frequency range (LF); (2) the delay between target signal and tracking movement (DL); and (3) a measure of tracking quality or over-all similarity in the shape of target signal and tracking movement (Q). Clumsy children in both age-groups had a lower tracking quality (Q) and longer delay (DL) than the normal children. Disturbances in the regulation of attention seemed to affect tracking performance, particularly of the six- to seven-year-old clumsy children. There was no significant difference between normal and clumsy children in the effect of visual feedback on tracking performance. This suggests that clumsiness is not linked to disturbance of integration of visual feedback information and motor processes.  相似文献   
10.
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