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   26024篇
  免费   1350篇
  国内免费   72篇
耳鼻咽喉   363篇
儿科学   2046篇
妇产科学   611篇
基础医学   2973篇
口腔科学   453篇
临床医学   1424篇
内科学   4828篇
皮肤病学   992篇
神经病学   1135篇
特种医学   1023篇
外科学   3878篇
综合类   961篇
一般理论   10篇
预防医学   1274篇
眼科学   1312篇
药学   2155篇
中国医学   141篇
肿瘤学   1867篇
  2023年   146篇
  2022年   375篇
  2021年   722篇
  2020年   404篇
  2019年   471篇
  2018年   681篇
  2017年   450篇
  2016年   656篇
  2015年   578篇
  2014年   911篇
  2013年   1074篇
  2012年   1522篇
  2011年   1625篇
  2010年   887篇
  2009年   711篇
  2008年   1243篇
  2007年   1317篇
  2006年   1132篇
  2005年   1070篇
  2004年   968篇
  2003年   892篇
  2002年   800篇
  2001年   725篇
  2000年   686篇
  1999年   604篇
  1998年   274篇
  1997年   198篇
  1996年   166篇
  1995年   147篇
  1994年   130篇
  1993年   145篇
  1992年   367篇
  1991年   399篇
  1990年   355篇
  1989年   374篇
  1988年   325篇
  1987年   284篇
  1986年   277篇
  1985年   286篇
  1984年   222篇
  1983年   184篇
  1979年   242篇
  1978年   159篇
  1977年   148篇
  1976年   137篇
  1975年   164篇
  1974年   154篇
  1973年   176篇
  1972年   138篇
  1971年   122篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
The 96 h LC50 values of six insecticides were determined on a non-target epigeic earthworm Perionyx excavatus under laboratory conditions. Cypermethrin was found most toxic to P. excavatus (LC50-0.008 mg/kg), followed by endosulfan (LC50-0.03 mg/kg), carbaryl (LC50-6.07 mg/kg), chlorpyrifos (LC50-7.3 mg/kg), aldicarb (LC50-10.63 mg/kg) and monocrotophos (LC50-13.04 mg/kg). When these LC50 values were compared with their respective recommended agricultural doses, aldicarb and carbaryl appeared more dangerous than other pesticides because of their lower LC50 values than their respective recommended agricultural dose. Mean lethal time to cause 50% mortality at recommended agricultural dose (LT50) also indicated that aldicarb achieved the fastest LT50 (26 h) followed by endosulfan (38 h) and carbaryl (44 h) indicating the danger of these pesticides to P. excavatus.  相似文献   
33.
34.
Infections caused by extended-spectrum beta-lactamase (ESBL)-producing pathogens, particularly Klebsiella pneumoniae, are increasing. The epidemiology of ESBL-producing K. pneumoniae, the mechanisms of resistance, and treatment strategies for infections caused by these organisms are reviewed.  相似文献   
35.
36.
37.
38.
Object Intracranial aneurysms are rare in children and have different epidemiological, clinical, and morphological characteristics and outcome from those in adults. Materials and methods We analyzed demographic, clinical, radiologic features, treatment, and outcome in 55 patients <18 years of age, treated from Jan 1995 through December 2005. Results Intracranial aneurysms in children below 18 years constituted 4% of all intracranial aneurysms. Internal Carotid artery (ICA) bifurcation was the commonest location. About half of the aneurysms were complex. Three-fourth of the patients required surgical treatment. Two patients died, constituting 5% mortality. Two patients (5%) had poor outcome, whereas the majority (90%) had a favorable outcome. Conclusions Pediatric aneurysms have male predominance, higher incidence of clinical features of mass effect or seizures, high incidence of large, traumatic/mycotic aneurysms, associated illnesses and ICH/IVH and hydrocephalus, better Hunt and Hess grades at presentation, ICA bifurcation as the commonest site, and better outcome than their adult counterparts.  相似文献   
39.
BACKGROUND: Various malignancies and cytotoxic chemotherapy have been proposed to increase the risk of reactivation of tuberculosis. Available literature to support this observation is still conflicting. There is scarcity of data from countries with rampant tubercular infection, such as India, in this regard. DESIGN AND METHODS: In the present retrospective analysis, patients with high-grade non-Hodgkin's lymphoma with past history of tuberculosis and have had adequate antitubercular therapy were identified from a Lymphoma Group study. These patients were followed up during cytotoxic chemotherapy and later to assess the risk of reactivation. RESULTS: A cohort of eight patients with past history of tuberculosis was selected from 141 patients of high-grade non-Hodgkin's lymphoma. The median age was 33.5 years (range, 24-53 years). Median duration between completion of antitubercular treatment and diagnosis of lymphoma was 5 years (range, 1.5-10 years). All patients received cyclical cytotoxic chemotherapy. The median duration of follow up after completion of chemotherapy was 5 years (range, 10 months to 5 years). None of these patients developed reactivation of tuberculosis. CONCLUSION: Cyclical chemotherapy for non-Hodgkin's lymphoma does not lead to reactivation of tuberculosis.  相似文献   
40.
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