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   27883篇
  免费   1919篇
  国内免费   107篇
耳鼻咽喉   286篇
儿科学   786篇
妇产科学   594篇
基础医学   4247篇
口腔科学   2527篇
临床医学   2258篇
内科学   5611篇
皮肤病学   598篇
神经病学   2109篇
特种医学   587篇
外国民族医学   1篇
外科学   3081篇
综合类   351篇
一般理论   7篇
预防医学   3202篇
眼科学   351篇
药学   2014篇
中国医学   281篇
肿瘤学   1018篇
  2023年   275篇
  2022年   654篇
  2021年   1065篇
  2020年   734篇
  2019年   922篇
  2018年   1057篇
  2017年   789篇
  2016年   807篇
  2015年   944篇
  2014年   1212篇
  2013年   1447篇
  2012年   2210篇
  2011年   2432篇
  2010年   1280篇
  2009年   955篇
  2008年   1599篇
  2007年   1507篇
  2006年   1384篇
  2005年   1128篇
  2004年   993篇
  2003年   885篇
  2002年   788篇
  2001年   553篇
  2000年   604篇
  1999年   482篇
  1998年   185篇
  1997年   122篇
  1996年   121篇
  1995年   112篇
  1994年   96篇
  1993年   79篇
  1992年   216篇
  1991年   206篇
  1990年   197篇
  1989年   190篇
  1988年   177篇
  1987年   133篇
  1986年   122篇
  1985年   121篇
  1984年   101篇
  1983年   80篇
  1981年   46篇
  1979年   83篇
  1978年   76篇
  1975年   54篇
  1974年   62篇
  1973年   62篇
  1970年   60篇
  1969年   47篇
  1967年   54篇
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
991.
IntroductionDespite the growing interest in the study of Gram-negative bacilli (GNB) infections, very little information on osteomyelitis caused by GNB is available in the medical literature.Objectives and methods: To assess clinical and microbiological features of 101 cases of osteomyelitis caused by GNB alone, between January 2007 and January 2009, in a reference center for the treatment of high complexity traumas in the city of São Paulo.ResultsMost patients were men (63%), with median age of 42 years, affected by chronic osteomyelitis (43%) or acute osteomyelitis associated to open fractures (32%), the majority on the lower limbs (71%). The patients were treated with antibiotics as inpatients for 40 days (median) and for 99 days (median) in outpatient settings. After 6 months follow-up, the clinical remission rate was around 60%, relapse 19%, amputation 7%, and death 5%. Nine percent of cases were lost to follow-up. A total of 121 GNB was isolated from 101 clinical samples. The most frequently isolated pathogens were Enterobacter sp. (25%), Acinetobacter baumannii (21%) e Pseudomonas aeruginosa (20%). Susceptibility to carbapenems was about 100% for Enterobacter sp., 75% for Pseudomonas aeruginosa and 60% for Acinetobacter baumannii.ConclusionOsteomyelitis caused by GNB remains a serious therapeutic challenge, especially when associated to nonfermenting bacteria. We emphasize the need to consider these agents in diagnosed cases of osteomyelitis, so that an ideal antimicrobial treatment can be administered since the very beginning of the therapy.  相似文献   
992.
993.
A major threat to tuberculosis (TB) control programs is the emergence of drug resistant Mycobacterium tuberculosis strains that cause TB that cannot be cured by standard anti-TB drug regimens. Because few data exist on MDR-TB in this region of the country, we performed an epidemiologic study that combined conventional and molecular analysis of MDR-TB cases from Rio Grande do Sul (RS) that were diagnosed in this period and included cases that were under treatment with second line drug schemes. Included were 121 MDR cases and sequencing of rpoB and katG showed that 106 (87.6%) strains were mutated in rpoB and 97 (80.2%) in katG. Spoligotyping demonstrated that the LAM genotype was predominant (n?=?70, 57.8%) and included the largest group composed by 22 (18.1%) strains with the LAM5 ST93 genotype. Other main genotypes belonged to the families T (n?=?22, 18.2%), U family (n?=?16, 13.2%), Haarlem (n?=?5, 4.1%) and X (n?=?1, 0.8%). Genotyping by IS6110-RFLP analysis showed 51 distinct fingerprints, 38 (31.4%) of these observed only once and the other 13 patterns being shared among the rest of the isolates (n?=?83, 68.6%). Among the 22 strains that were LAM5 ST93, only two had different IS6110-RFLP genotypes. In conclusion, there exists a high degree of M.?Tuberculosis genotype clustering among MDR-TB cases in Rio Grande do Sul. Moreover, we observed a large MDR-TB outbreak.  相似文献   
994.
995.

Introduction  

Obstructive sleep apnea–hypopnea syndrome (OSAHS) is an emerging public health concern. Although different treatments for OSAHS had been proposed, continuous positive airway pressure (CPAP) is the first-line treatment in moderate to serious OSAHS in which success can be achieved by increasing compliance to CPAP.  相似文献   
996.
Graefe's Archive for Clinical and Experimental Ophthalmology - To assess the outcomes of vitrectomy with or without cataract surgery for the treatment of idiopathic ERM in phakic eyes and...  相似文献   
997.
In this work, we describe a new one-pot synthesis route of valuable linalool oxidation derivatives (i.e., 2-(5-methyl-5-vinyltetrahydrofuran-2-yl propan-2-ol) (1a)), 2,2,6-trimethyl-6-vinyltetrahydro-2H-pyran-3-ol (1b) and diepoxide (1c), using a green oxidant (i.e., hydrogen peroxide) under mild conditions (i.e., room temperature). Lacunar Keggin heteropolyacid salts were the catalysts investigated in this reaction. Among them, Na7PW11O39 was the most active and selective toward oxidation products. All the catalysts were characterized by FT-IR, TG/DSC, BET, XRD analyses and potentiometric titration. The main reaction parameters were assessed. Special attention was dedicated to correlating the composition and properties of the catalysts and their activity.

In this work, the catalyst Na7PW11O39 was used in a new one-pot synthesis route to oxidize linalool to valuable derivatives (i.e., vinyltetrahydrofuran, vinyltetrahydropyran, and diepoxide), using a green oxidant (H2O2) at room temperature.  相似文献   
998.
999.
1000.
Post‐transplant lymphoproliferative disorder (PTLD) is a major and potentially life‐threatening complication after solid‐organ transplantation. The aim of this study was to describe the disease characteristics, clinical practices, and survival related to PTLD in adult orthotopic liver transplant (OLT) recipients in South America. We conducted a survey at four different transplant groups from Argentina, Brazil, and Chile. Among 1621 OLT recipients, 27 developed PTLD (1.7%); the mean age at diagnosis was 53.7 (±14) yr with a mean time of 39.7 (±35.2) months from OLT to PTLD diagnosis. Initial therapy included reduction in immunosuppression alone in 23.1% of the patients. Either rituximab or chemotherapy was employed as initial or second‐line therapy in 76.9% of the patients. PTLD location was frequently extranodal (80.7%) and mostly involving the transplanted liver (59.3%). The overall survival at one and five yr post‐PTLD diagnosis was 53.8% and 46.2%, respectively. Significant univariate risk factors for post‐PTLD mortality included lactate dehydrogenase ≥250 U/L (HR 9.66, p = 0.02), stage III/IV PTLD (HR 5.34, p = 0.004), and HCV infection (HR 7.68, p = 0.01). In conclusion, PTLD in OLT adult recipients is predominantly extranodal, and although mortality is high, long‐term survival is possible.  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