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   23109篇
  免费   1555篇
  国内免费   426篇
耳鼻咽喉   124篇
儿科学   411篇
妇产科学   308篇
基础医学   3092篇
口腔科学   320篇
临床医学   2945篇
内科学   5106篇
皮肤病学   361篇
神经病学   1117篇
特种医学   476篇
外国民族医学   1篇
外科学   1993篇
综合类   1504篇
现状与发展   2篇
一般理论   47篇
预防医学   3617篇
眼科学   373篇
药学   1450篇
  25篇
中国医学   546篇
肿瘤学   1272篇
  2024年   65篇
  2023年   2124篇
  2022年   4499篇
  2021年   6873篇
  2020年   4505篇
  2019年   300篇
  2018年   283篇
  2017年   243篇
  2016年   254篇
  2015年   282篇
  2014年   459篇
  2013年   495篇
  2012年   364篇
  2011年   454篇
  2010年   379篇
  2009年   366篇
  2008年   367篇
  2007年   365篇
  2006年   348篇
  2005年   277篇
  2004年   288篇
  2003年   247篇
  2002年   163篇
  2001年   140篇
  2000年   117篇
  1999年   93篇
  1998年   94篇
  1997年   75篇
  1996年   87篇
  1995年   52篇
  1994年   30篇
  1993年   41篇
  1992年   28篇
  1991年   34篇
  1990年   26篇
  1989年   14篇
  1988年   11篇
  1987年   9篇
  1985年   37篇
  1984年   37篇
  1983年   23篇
  1982年   24篇
  1981年   23篇
  1980年   18篇
  1979年   16篇
  1977年   10篇
  1976年   5篇
  1975年   10篇
  1974年   6篇
  1973年   18篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
991.
992.
Coronavirus disease 2019 or most commonly known as COVID-19 is a trending global infectious disease which a few months ago was affirmed as a global health emergency or a pandemic by the WHO Emergency Committee. The common symptoms manifested in this pandemic disease are high grade fever, cough, fatigue, shortness of breath and flu like symptom which can evolve into severe respiratory disorders such as pneumonia, acute respiratory distress syndrome (ARDS) and/or end-organ failure. Factors that contribute to the severity or high mortality rate in COVID-19 include old age, comorbidities like hypertension, diabetes, hyperlipidaemia, neutrophilia, and organ and coagulation dysfunction. Disseminated intravascular coagulation and other various coagulopathies including Venous thromboembolism have known to become a major contributing factor to high mortality rate. Venous thromboembolism is a disease which is a combination of deep vein thrombosis and pulmonary embolism. Prophylactic anticoagulation in patients prone to or with a pre-existing history of venous thromboembolism is associated with decreased mortality in severe COVID-19 pneumonia. This review article focuses upon COVID-19 and increased incidence of venous thromboembolism in patients infected by COVID-19 along with the role it has in high mortality rate in COVID-19 patients.  相似文献   
993.
During the ongoing COVID-19 pandemic, healthcare professionals are at the forefront of managing the highly infectious coronavirus. As the most common route of transmission is via aerosols and droplet inhalation, it is critical for healthcare workers to have the correct personal protective equipment (PPE) including gowns, masks and goggles. Surgical masks are not effective in preventing the influenza and SARS, so they are unlikely to be able to resist contaminated aerosols from entering the respiratory system. Therefore, it is vital to use respirators which have been proven to offer better protection against droplets, aerosols and fluid penetration and which form a tight seal around the mouth and nose. Various types of respirators are used in healthcare settings, such as half-mask filtering facepiece respirators (FFRs) and powered air-purifying respirators (PAPRs). The most commonly used FFR is the N95 disposable respirator, which is tight fitting and has a 95% or above particle filtering efficiency for a median particle size of 0.3 µm. This review discusses respirators, their purpose, types, clinical efficiency and proper donning and doffing techniques.  相似文献   
994.
995.
IntroductionThe use of convalescent plasma (CP) transfusions is very valuable in the current COVID-19 outbreak, given that there are no specific preventive and therapeutic options.Materials and methods50 patients with severe COVID-19 disease treated with convalescent plasma transfusion were included in the study. The efficacy of CP and in which situations it was effective were investigated.Conclusion80 % of the patients recovered, and 20 % died in our study. The mean age of the patients who died was found to be higher than the patients who recovered. CRP, ferritin, D-dimer, neutrophil, MPV, and NLR counts were found to be higher, and lymphocyte and platelet counts were lower in the deceased group after CP. It was determined that patients who received CP within the first five days were hospitalized for a shorter period.DiscussionAdministration of CP transfusion within the first five days in severe COVID-19 patients has been shown to reduce hospital stay length.  相似文献   
996.
BackgroundCOVID-19 virus has caused the world’s deadliest pandemic. Early April 2020, the Delhi Government made it compulsory for people to wear face masks while going outdoors to curb disease spread. Prolonged use of surgical masks during the pandemic has been reported to cause many adverse effects. Intermittent hypoxia has been shown to activate erythropoietin (EPO leading to increased hemoglobin mass.AimTo analyze whether face mask induced intermittent hypoxia has any effect on the hemoglobin levels of healthy blood donors.Materials and methodsWe retrospectively analyzed donor data from 1st July 2019-31st December 2020 for hemoglobin distribution across hemoglobin ranges and donor deferral on basis of hemoglobin. Study population was divided into two cohorts Group 1- (1st July 2019-31 st March 2020): before implementation of mandatory face masks Group 2- (1st April 2020-31 st December 2020): after implementation of mandatory face masksResultsMean Hb of blood donors in Group 2 (15.01 ± 1.1 g/dl) was higher than Group1 (14.49 ± 1.15 g/dl), (p < 0.0001). 47.1 % group2 donors had Hb of 16.1−18 g/dl compared to group1 (38.4 %). 52.9 % group 2 donors had Hb between 12.5−15 g/dl compared to 61.6 % Group 1 (p < 0.05). Deferral due to anemia was lesser in group 2 compared to group 1 (p < 0.00001). Group 2 had significantly higher deferral due to high Hb (>18 gm/dl) was than Group 1 (p = 0.0039).ConclusionThis study including 19504 blood donors spanning over one and a half year shows that prolonged use of face mask by blood donors may lead to intermittent hypoxia and consequent increase in hemoglobin mass.  相似文献   
997.
For more than a year the whole world is suffering from the COVID-19 pandemic with no treatment option in sight. Administration of plasma from convalescent donors containing anti-SARS-CoV-2 antibodies, though promising according to case reports, failed to show a clear benefit in a greater number of trials.One reason could be varying and low antibody contents in a majority of plasma units hampering standardization and clinical efficacy. Besides, other plasma components unnecessarily transfused like coagulation factors might promote hypercoagulation seen in severe COVID-19 etiopathology.We therefore hypothesized that instead of collecting whole plasma units, convalescent donors could donate solely immunoglobulins by undergoing immunoadsorption, a mode of therapy regularly applied in autoimmune diseases. Here, we report the results of the first two antibody donations performed at the University Hospital Düsseldorf.In both cases, immunoadsorptions were very well tolerated with no side effects. Collected and neutralized eluates were concentrated using tangential flow filtration increasing the concentration of immunoglobulins 10fold as compared to peripheral blood and leading to probably eight times more neutralizing antibodies than in one plasma unit.Therefore, immunoadsorption can be used as a method of antibody donation. Whether these donated antibodies can be used as passive immunization in acutely infected patients remains to be elucidated.  相似文献   
998.
Call back as a procedure to report post donation symptoms or illness by donors has been established since 2009 in Iranian Blood Transfusion Organization (IBTO). During the first phase of COVID-19 outbreak, all blood donors were requested to report any respiratory infection symptoms after donation. The study investigated the callback data of COVID-19 in Tehran Blood Center during the first 3 months of the outbreak in Iran. The purpose of this study was to estimate the frequency of post donation COVID-19 related call back reports and determine its implications for blood donors and patients.A telephone interview was conducted with donors who had reported COVID-19 symptoms. Some questions were asked to evaluate donor′s health at the time of blood donation. The donors categorized into three groups: laboratory-confirmed, suspected, and COVID-19 irrelevant based on their answers. In cases that the blood component obtained from a laboratory-confirmed donor had been released, the hospital was notified and asked to follow up the recipient for COVID-19.The results showed 30 donors (0.08 %) had callback related to COVID-19 and 76.63 % of the obtained component was disposed. The results also showed that only one donor had a laboratory-confirmed result with the RBC unit processed from her whole blood released for transfusion. The RBC unit recipient did not show any signs or symptoms of infection during a 46-day follow-up.Concluded that callback system was effective to remove most of the components obtained from the donors who reported to be COVID-19 suspected or confirmed. Moreover, the result did not support virus transmission through blood transfusion.  相似文献   
999.
IntroductionPassive antibody therapy has been used to immunize vulnerable people against infectious agents. In this study, we aim to investigate the efficacy of convalescent plasma (CP) in the treatment of severe and critically ill patients diagnosed with COVID-19.MethodThe data of severe or critically ill COVID-19 patients who received anti-SARS-CoV-2 antibody-containing CP along with the antiviral treatment (n = 888) and an age-gender, comorbidity, and other COVID-19 treatments matched severe or critically ill COVID-19 patients at 1:1 ratio (n = 888) were analyzed retrospectively.ResultsDuration in the intensive care unit (ICU), the rate of mechanical ventilation (MV) support and vasopressor support were lower in CP group compared with the control group (p = 0.001, p = 0.02, p = 0.001, respectively). The case fatality rate (CFR) was 24.7 % in the CP group, and it was 27.7 % in the control group. Administration of CP 20 days after the COVID-19 diagnosis or COVID-19 related symptoms were associated with a higher rate of MV support compared with the first 3 interval groups (≤5 days, 6?10 days, 11?15 days) (p=0.001).ConclusionCP therapy seems to be effective for a better course of COVID-19 in severe and critically ill patients.  相似文献   
1000.
BackgroundData on convalescent plasma therapy (CPT) in patients of hematological malignancies with severe Covid-19 is scarce.ObjectiveTo study 14-day mortality in patients who received CPT.Patients & methodsRetrospective multicentre observational study conducted in 4 centres treating haematological malignancies across Delhi-national capital region. Total 33 haematological malignancies patients with severe Covid-19 who received CPT were analysed.ResultsThe median age of the study cohort was 62 years (18–80 years). Twenty one percent patients had 1 comorbidity, 18 % had 2 comorbidities and 6% patients had 3 and 5 comorbidities each. Twenty four patients were on active therapy. Sixty nine percent of patients required ICU stay. Twenty five patients received plasma therapy within 7 days (early) of diagnosis of Covid-19 infection. Median day of plasma infusion from date of diagnosis of Covid-19 infection was 4 days (range: 2–25 days). Patient who had early initiation of plasma therapy had shorter duration of hospitalisation (12.7 vs 24.3 days, p = 0.000). Overall mortality in the cohort was 45.5%. There was no effect of disease status, active therapy, presence of comorbidity on mortality. There was no difference in the mortality in patients receiving early vs late initiation of plasma therapy or in patients receiving one versus two plasma therapy.ConclusionsWe provide a large series of patients with hematological malignancies and role of CPT in this group.  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