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   1178篇
  免费   91篇
  国内免费   10篇
耳鼻咽喉   5篇
儿科学   60篇
妇产科学   15篇
基础医学   147篇
口腔科学   47篇
临床医学   99篇
内科学   233篇
皮肤病学   42篇
神经病学   34篇
特种医学   152篇
外国民族医学   1篇
外科学   187篇
综合类   48篇
预防医学   71篇
眼科学   5篇
药学   92篇
中国医学   1篇
肿瘤学   40篇
  2021年   24篇
  2020年   9篇
  2019年   9篇
  2018年   11篇
  2017年   17篇
  2016年   17篇
  2015年   26篇
  2014年   18篇
  2013年   30篇
  2012年   29篇
  2011年   30篇
  2010年   39篇
  2009年   49篇
  2008年   32篇
  2007年   29篇
  2006年   22篇
  2005年   22篇
  2004年   37篇
  2003年   21篇
  2002年   20篇
  2001年   16篇
  2000年   16篇
  1999年   32篇
  1998年   64篇
  1997年   69篇
  1996年   62篇
  1995年   43篇
  1994年   44篇
  1993年   45篇
  1992年   14篇
  1991年   22篇
  1990年   29篇
  1989年   23篇
  1988年   30篇
  1987年   31篇
  1986年   36篇
  1985年   13篇
  1984年   13篇
  1983年   13篇
  1982年   27篇
  1980年   9篇
  1979年   8篇
  1978年   11篇
  1977年   11篇
  1976年   11篇
  1975年   9篇
  1974年   8篇
  1972年   8篇
  1971年   9篇
  1970年   7篇
排序方式: 共有1279条查询结果,搜索用时 15 毫秒
1.
Marie Warrer Petersen  Tine Sylvest Meyhoff  Marie Helleberg  Maj-Brit Nørregaard Kjær  Anders Granholm  Carl Johan Steensen Hjortsø  Thomas Steen Jensen  Morten Hylander Møller  Peter Buhl Hjortrup  Mik Wetterslev  Gitte Kingo Vesterlund  Lene Russell  Vibeke Lind Jørgensen  Klaus Tjelle  Thomas Benfield  Charlotte Suppli Ulrik  Anne Sofie Andreasen  Thomas Mohr  Morten H. Bestle  Lone Musaeus Poulsen  Mette Friberg Hitz  Thomas Hildebrandt  Lene Surland Knudsen  Anders Møller  Christoffer Grant Sølling  Anne Craveiro Brøchner  Bodil Steen Rasmussen  Henrik Nielsen  Steffen Christensen  Thomas Strøm  Maria Cronhjort  Rebecka Rubenson Wahlin  Stephan Jakob  Luca Cioccari  Balasubramanian Venkatesh  Naomi Hammond  Vivekanand Jha  Sheila Nainan Myatra  Christian Gluud  Theis Lange  Anders Perner 《Acta anaesthesiologica Scandinavica》2020,64(9):1365-1375

Introduction

Severe acute respiratory syndrome coronavirus-2 has caused a pandemic of coronavirus disease (COVID-19) with many patients developing hypoxic respiratory failure. Corticosteroids reduce the time on mechanical ventilation, length of stay in the intensive care unit and potentially also mortality in similar patient populations. However, corticosteroids have undesirable effects, including longer time to viral clearance. Clinical equipoise on the use of corticosteroids for COVID-19 exists.

Methods

The COVID STEROID trial is an international, randomised, stratified, blinded clinical trial. We will allocate 1000 adult patients with COVID-19 receiving ≥10 L/min of oxygen or on mechanical ventilation to intravenous hydrocortisone 200 mg daily vs placebo (0.9% saline) for 7 days. The primary outcome is days alive without life support (ie mechanical ventilation, circulatory support, and renal replacement therapy) at day 28. Secondary outcomes are serious adverse reactions at day 14; days alive without life support at day 90; days alive and out of hospital at day 90; all-cause mortality at day 28, day 90, and 1 year; and health-related quality of life at 1 year. We will conduct the statistical analyses according to this protocol, including interim analyses for every 250 patients followed for 28 days. The primary outcome will be compared using the Kryger Jensen and Lange test in the intention to treat population and reported as differences in means and medians with 95% confidence intervals.

Discussion

The COVID STEROID trial will provide important evidence to guide the use of corticosteroids in COVID-19 and severe hypoxia.
  相似文献   
2.
3.
4.
During the intervening years since metoprolol was first reviewed in the Journal (1977), it has become widely used in the treatment of mild to moderate hypertension and angina pectoris. Although much data have accumulated, its precise mechanisms of action in these diseases remain largely uncertain. Optimum treatment of hypertension and angina pectoris with metoprolol is achieved through dose titration within the therapeutic range. It has been clearly demonstrated that metoprolol is at least as effective as other beta-blockers, diuretics and certain calcium antagonists in the majority of patients. Although a twice daily dosage regimen is normally used, satisfactory control can be maintained in many patients with single daily doses of conventional or, more frequently, slow release formulations. Addition of a diuretic may improve the overall response rate in hypertension. Several controlled trials have studied the effects of metoprolol administered during the acute phase and after myocardial infarction. In early intervention trials a reduction in total mortality was achieved in one moderately large trial of prolonged treatment, but in another, which excluded patients already being treated with beta-blockers or certain calcium antagonists and where treatment was only short term, mortality was significantly reduced only in 'high risk' patients. Overall results with metoprolol have not demonstrated that early intervention treatment in all patients produces clinically important improvement in short term mortality. Thus, the use of metoprolol during the early stages of myocardial infarction is controversial, largely because of the requirement to treat all patients to save a small number at 'high risk'. This blanket coverage approach to treatment may be more justified during the post-infarction follow-up phase since it has been shown that metoprolol slightly, but significantly, reduces the mortality rate for periods of up to 3 years. Metoprolol is generally well tolerated and its beta 1-selectivity may facilitate its administration to certain patients (e.g. asthmatics and diabetics) in whom non-selective beta-blockers are contraindicated. Temporary fatigue, dizziness and headache are among the most frequently reported side effects. After a decade of use, metoprolol is well established as a first choice drug in mild to moderate hypertension and stable angina, and is beneficial in post-infarction patients. Further study is needed in less well established areas of treatment such as cardiac arrhythmias, idiopathic dilated cardiomyopathy and hypertensive cardiomegaly.  相似文献   
5.
J P Monk  P Benfield 《Drugs》1990,39(5):741-756
Pentamidine is an aromatic diamidine derivative which has become one of the standard therapies for Pneumocystis carinii pneumonia (PCP), particularly in patients with acquired immunodeficiency syndrome (AIDS). However, with parenteral administration of the drug there is a high risk of toxicity. Inhaled pentamidine produces much higher concentrations of drug on the bronchoalveolar surface with minimal systemic absorption. It has been used successfully for the treatment of PCP in AIDS patients, but its most valuable contribution has been as prophylaxis in AIDS patients at high risk of developing PCP. In prospective controlled studies there has been greater than 80% reduction in relapse rate with pentamidine. The reduction in relapse rate among patients who have experienced one previous episode of PCP has been 50 to 100% compared with historical control groups, over a follow-up period averaging about 6 months. Significant systemic adverse effects to inhaled pentamidine are rare. Respiratory effects associated with inhalation are common but usually controllable without treatment discontinuation. The ideal particle size for even distribution of pentamidine throughout the lung is considered to be 1 to 2 microns. Jet nebulisers such as the 'Respirgard II' system produce a mass median aerodynamic diameter (MMAD) of particles in this range. Ultrasonic nebulisers produce larger particles. The implication from this difference is that while ultrasonic nebulisers may have poorer alveolar distribution and the incidence of local side effects (common with all formulations) may be higher, total drug delivery may be more efficient allowing effective PCP prophylaxis with lower dosages (120 mg vs 300 mg monthly). However, there are no data available comparing the efficacies and tolerabilities of the different formulations of inhaled pentamidine. Nevertheless, inhaled pentamidine would seem poised to become routine prophylaxis in patients with AIDS or AIDS-related complex at risk of developing PCP.  相似文献   
6.
7.
A Fitton  P Benfield 《Drugs》1990,39(2):308-330
Dopexamine hydrochloride is a novel synthetic catecholamine, structurally related to dopamine, with marked intrinsic agonist activity at beta 2-adrenoceptors, lesser agonist activity at dopamine DA1- and DA2-receptors and beta 1-adrenoceptors, and an inhibitory action on the neuronal catecholamine uptake mechanism. The drug is administered by intravenous infusion, and is characterized by a rapid onset and short duration of action. Short term haemodynamic studies in volunteers and patients with severe chronic heart failure have indicated that dopexamine hydrochloride reduces afterload through pronounced arterial vasodilatation, increases renal perfusion by selective renal vasodilation and evokes mild cardiac stimulation through direct and indirect positive inotropism. Preliminary small-scale noncomparative studies indicate that dopexamine hydrochloride displays beneficial haemodynamic effects in patients with acute heart failure and those requiring haemodynamic support following cardiac surgery, and that these effects are substantially maintained during longer term administration (less than or equal to 24 hours). Dopexamine hydrochloride appears to be generally well tolerated. Nausea and vomiting are the most frequently reported adverse effects, and respond to dosage reduction. Occasional reports of chest pain/angina pectoris precipitated by tachycardia indicates the need for caution in the use of dopexamine hydrochloride in patients with ischaemic heart disease. Thus, dopexamine hydrochloride may prove to be a useful alternative to dopamine and dobutamine in the treatment of acute heart failure and the postoperative management of low cardiac output states, although controlled studies are required to establish its efficacy and tolerability with respect to that of established therapies.  相似文献   
8.
Cutaneous metastasis of vaginal carcinoma is extremely rare. So far, the total number of reported skin metastasis of vaginal carcinoma is only one. We present another case with an unusual manifestation of vagina carcinoma metastasis: skin metastasis presenting as a leg ulcer on the lower leg.  相似文献   
9.
Myosin has been purified from chicken pectoralis muscle at various stages of development, from 10 days' incubation to approximately 10 months after hatching. Embryonic myosin from the earliest stage showed a high level of ATPase activity, similar to that obtained for adult pectoralis myosin. Two-dimensional peptide mapping of partial chymotryptic digests showed, however, that is heavy chain is quite different from that of adult fast myosin. The immunological crossreactivity observed between embryonic myosin and adult fast (pectoralis) myosin is therefore due to shared antigenic determinants rather than the presence of any adult isoforms. In an accompanying paper we will show that embryonic myosin at 10 days' incubation is not a single species, but consists of at least two heavy chain isozymes. The minor fraction binds slow light chains preferentially, and appears to be largely responsible for the observed crossreactivity with slow (ALD) myosin. None of the embryonic myosins is equivalent to the adult forms. Prior to hatching, LC3f is present only in very small amounts (less than 5%), and the adult light chain pattern, containing LC1f and LC3f in equimolar amounts, is not generated until after one week post-hatching. At about that time a new heavy chain population is detected, different from either the embryonic heavy chain or the adult heavy chain. The adult heavy chain peptide pattern appears from about three weeks' post-hatching, but a map indistinguishable from that of adult myosin is not observed until about 26 weeks. None of the observed differences in peptide maps can be related to different strains of chicken; pectoralis myosin from adult White Rock gave an identical map to that from White Leghorn. Unexpectedly, posterior latissimus dorsi (PLD) myosin from White Leghorn appears to be different from pectoralis myosin from the same strain, despite the histochemical and immunocytochemical similarity of the two muscles. We conclude that myosin polymorphism is widespread in muscle tissue, and that the expression of myosin isozymes and their subunits is under developmental regulation.  相似文献   
10.
Localization of a gene for otosclerosis to chromosome 15q25-q26   总被引:5,自引:0,他引:5  
Among white adults otosclerosis is the single most common cause of hearing impairment. Although the genetics of this disease are controversial, the majority of studies indicate autosomal dominant inheritance with reduced penetrance. We studied a large multi- generational family in which otosclerosis has been inherited in an autosomal dominant pattern. Five of16 affected persons have surgically confirmed otosclerosis; the remaining nine have a conductive hearing loss but have not undergone corrective surgery. To locate the disease- causing gene we completed genetic linkage analysis using short tandem repeat polymorphisms (STRPs) distributed over the entire genome. Multipoint linkage analysis showed that only one genomic region, on chromosome 15q, generated a lod score >2.0. Additional STRPs were typed in this area, resulting in a lod score of 3.4. STRPs FES (centromeric) and D15S657 (telomeric) flank the 14. 5 cM region that contains an otosclerosis gene.   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