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   1276776篇
  免费   92755篇
  国内免费   1988篇
耳鼻咽喉   18185篇
儿科学   42262篇
妇产科学   37843篇
基础医学   187034篇
口腔科学   35382篇
临床医学   108124篇
内科学   251489篇
皮肤病学   26498篇
神经病学   99209篇
特种医学   49982篇
外国民族医学   366篇
外科学   197593篇
综合类   26516篇
现状与发展   1篇
一般理论   300篇
预防医学   92588篇
眼科学   29056篇
药学   97760篇
  1篇
中国医学   2497篇
肿瘤学   68833篇
  2018年   11810篇
  2015年   11620篇
  2014年   16003篇
  2013年   24358篇
  2012年   33558篇
  2011年   35955篇
  2010年   21215篇
  2009年   20021篇
  2008年   34982篇
  2007年   37954篇
  2006年   38512篇
  2005年   37812篇
  2004年   36401篇
  2003年   35379篇
  2002年   34929篇
  2001年   58098篇
  2000年   59591篇
  1999年   50693篇
  1998年   14235篇
  1997年   12811篇
  1996年   13073篇
  1995年   12348篇
  1994年   11761篇
  1993年   10861篇
  1992年   40988篇
  1991年   40364篇
  1990年   39886篇
  1989年   38712篇
  1988年   36109篇
  1987年   35349篇
  1986年   33723篇
  1985年   32135篇
  1984年   23922篇
  1983年   20818篇
  1982年   12380篇
  1981年   10927篇
  1980年   10206篇
  1979年   22635篇
  1978年   15877篇
  1977年   13730篇
  1976年   12972篇
  1975年   14201篇
  1974年   16682篇
  1973年   16076篇
  1972年   15320篇
  1971年   14229篇
  1970年   13214篇
  1969年   12732篇
  1968年   11978篇
  1967年   10478篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
961.
Heart transplantation (HTx) is a useful therapy for end‐stage Chaga? cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.  相似文献   
962.
HLA and immunology laboratories are an integral part of clinical kidney transplant programs. They assist transplant clinicians with evaluating the immunological suitability of potential recipients for transplantation and selecting donor-recipient combinations with a low risk of immunological failure. With sophisticated new techniques becoming available for posttransplant immunological monitoring, laboratories play an increasing supporting role during posttransplant follow up. The level of precision at which immunological testing predicts clinical outcome, however, leaves room for improvement. In this article, we summarize the current state of diagnostics, discuss problems, and point out promising developments.  相似文献   
963.
Turndowns of offers of deceased donor kidneys for transplantation can contribute to inefficiencies in the organ distribution system and inequality in access to donated organs. Match run data were obtained for 4967 'good' kidneys placed and transplanted in 2005 after fewer than 50 offers. These kidneys were not recovered from donation after cardiac death or expanded criteria donors, or from donors with a history of substance abuse. On average, these good kidneys were not accepted until after seven offers to candidates and after offers to 2.4 programs. Models for the likelihood of acceptance found several donor and candidate characteristics to be significantly related to acceptance rates (p < 0.05). After accounting for these variables, there remained 2- to 3-fold differences among transplant programs in acceptance rates. These models could be used to identify kidney transplant centers with exceptional acceptance practices. Several strategies might be employed to increase acceptance rates for good organs.  相似文献   
964.
965.
966.
Chronic obstructive pulmonary disease (COPD) is the fifth cause of morbidity and mortality in the developed world and represents a substantial economic and social burden. Patients experience a progressive deterioration up to end-stage COPD, characterised by very severe airflow limitation, severely limited and declining performance status with chronic respiratory failure, advanced age, multiple comorbidities and severe systemic manifestations/complications. COPD is frequently underdiagnosed and under-treated. Today, COPD develops earlier in life and is less gender specific. Tobacco smoking is the major risk factor for COPD, followed by occupation and air pollution. Severe deficiency for alpha(1)-antitrypsin is rare; several phenotypes are being associated with elevated risk for COPD in the presence of risk factor exposure. Any patient presenting with cough, sputum production or dyspnoea should be assessed by standardised spirometry. Continued exposure to noxious agents promotes a more rapid decline in lung function and increases the risk for repeated exacerbations, eventually leading to end-stage disease. Without major efforts in prevention, there will be an increasing proportion of end-stage patients who can live longer through long-term oxygen therapy and assisted ventilation, but with elevated suffering and huge costs. Smoking prevention and smoking cessation are the most important epidemiological measurements to counteract chronic obstructive pulmonary disease epidemics.  相似文献   
967.
968.
969.
970.
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