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   7759篇
  免费   465篇
  国内免费   24篇
耳鼻咽喉   62篇
儿科学   243篇
妇产科学   70篇
基础医学   1456篇
口腔科学   287篇
临床医学   658篇
内科学   1242篇
皮肤病学   249篇
神经病学   835篇
特种医学   333篇
外科学   940篇
综合类   48篇
一般理论   2篇
预防医学   307篇
眼科学   417篇
药学   557篇
中国医学   11篇
肿瘤学   531篇
  2023年   22篇
  2022年   61篇
  2021年   118篇
  2020年   92篇
  2019年   83篇
  2018年   123篇
  2017年   114篇
  2016年   147篇
  2015年   203篇
  2014年   224篇
  2013年   278篇
  2012年   419篇
  2011年   414篇
  2010年   287篇
  2009年   278篇
  2008年   537篇
  2007年   442篇
  2006年   468篇
  2005年   477篇
  2004年   518篇
  2003年   472篇
  2002年   440篇
  2001年   154篇
  2000年   131篇
  1999年   137篇
  1998年   104篇
  1997年   105篇
  1996年   78篇
  1995年   63篇
  1994年   48篇
  1993年   53篇
  1992年   68篇
  1991年   60篇
  1990年   49篇
  1989年   72篇
  1988年   55篇
  1987年   53篇
  1986年   44篇
  1985年   46篇
  1984年   36篇
  1983年   31篇
  1982年   34篇
  1981年   31篇
  1980年   32篇
  1979年   38篇
  1978年   27篇
  1977年   33篇
  1975年   24篇
  1973年   28篇
  1972年   29篇
排序方式: 共有8248条查询结果,搜索用时 19 毫秒
1.
2.
3.
Facet joints play an important role in intervertebral load transmission and are crucial for rotational kinematics. Clinically, the role of facet joints as a possible source of low back pain is seen as controversial and at present is not sufficiently investigated. In this study, human lumbar facet (zygapopyhysial) joints from donors with advanced age were analyzed macroscopically, for degenerative changes. The aim was to determine the extent and morphology of degenerative changes in these joints. Lumbar facet joints (L1–L5) of 32 donors were studied (mean age 80.1±11.2 years). Joint capsules were carefully removed and joint surfaces (5 zones) examined using magnifying glasses and probes. In the result, the majority of facet joints showed cartilage defects of varying extent. Defects were located mostly at the margins of the articular surface, the central zone being relatively well preserved. Defect localization was different between superior (most cartilage defects in superior zone) and inferior (most defects inferiorly) facets. Further, defects were more severe caudal (level of L5) and in older persons. Osteophytes were present in up to 30%, located mostly at the latero-dorsal enthesis of the joint capsule on the superior facet. In conclusion, most margins of the articular facets are subject to degenerative changes in the lumbar spine of elderly persons, the topographical pattern being different in superior and inferior facets. This observation can be explained by the segmental motion patterns during extension/flexion movements of the facets. Sometimes, due to the marginal extension, it is obvious that not all changes can be assessed by CT or MRI.  相似文献   
4.
Adamantinoma of long bones is one of the rarest of malignant bone tumors; it is commonly located in the middle or lower third of the diaphysis of the tibia. A case with multiple occurrences affecting both the tibia and fibula is presented. En bloc resection with wide operative margins was performed, and a large tibial defect of 23 cm was effectively bridged by a revascularized free fibular flap. At 13 months follow-up, there was no sign of local recurrence or metastasis, and the patient was mobile.  相似文献   
5.
6.
Alzheimer's disease (AD) patients often present with concurrent major depression (MD). To investigate the reasons for this comorbidity, e.g. MD being a risk factor for AD, or both diagnoses having a common neurobiology, the temporal relationship between the first onset of AD and of MD during lifetime was investigated-57 out of 146 AD patients had a lifetime diagnosis of MD. The correlation between the ages at onset of MD and dementia was calculated. The incidence of MD in AD patients in several 5-year-intervals before and after the onset of AD was compared with the average incidence of MD in the present AD sample and with the expected incidence of MD in the general population. No significant correlation between the onset of AD and of MD could be found after controlling for age, gender and the Mini-Mental-State. However, the incidence of MD 5 years before and after the onset of AD significantly exceeded the expected incidences-MD is only partially related to AD. However, the increased incidence of MD within 5 years before and after the onset of dementia may indicate that a common neurobiological process causes cognitive decline and depression in a subsample of AD patients.  相似文献   
7.
8.
9.
Operative mortality, postoperative morbidity and follow up data were analyzed retrospectively from 122 consecutive patients, over 65 years old undergoing elective aortocoronary bypass grafting for symptomatic relief of angina pectoris at the Plains Health Centre, Regina, Saskatchewan, from January 1980 to December 1985. There were two in-hospital deaths (operative mortality 1.6%). Definite perioperative myocardial infarction occurred in 12 patients (9.8%). The 120 survivors were followed for a mean of 32 months. There were three deaths during follow-up, giving a five-year probability of survival of 93%. Twenty-three clinical events (including deaths) occurred during follow-up, giving a five-year probability of event free survival of 72%. Ninety percent of patients say they are pleased with their operation. Seventy-eight percent are currently angina free. These data illustrate the effectiveness of aortocoronary bypass grafting in low risk elderly patients with symptomatic coronary artery disease.  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