全文获取类型
收费全文 | 37825篇 |
免费 | 2196篇 |
国内免费 | 203篇 |
专业分类
耳鼻咽喉 | 430篇 |
儿科学 | 1164篇 |
妇产科学 | 1008篇 |
基础医学 | 3790篇 |
口腔科学 | 1239篇 |
临床医学 | 3314篇 |
内科学 | 8162篇 |
皮肤病学 | 679篇 |
神经病学 | 2254篇 |
特种医学 | 1330篇 |
外国民族医学 | 4篇 |
外科学 | 6867篇 |
综合类 | 897篇 |
现状与发展 | 3篇 |
一般理论 | 27篇 |
预防医学 | 2568篇 |
眼科学 | 1363篇 |
药学 | 2935篇 |
1篇 | |
中国医学 | 294篇 |
肿瘤学 | 1895篇 |
出版年
2024年 | 39篇 |
2023年 | 425篇 |
2022年 | 1067篇 |
2021年 | 1670篇 |
2020年 | 999篇 |
2019年 | 1279篇 |
2018年 | 1613篇 |
2017年 | 1164篇 |
2016年 | 1251篇 |
2015年 | 1367篇 |
2014年 | 1725篇 |
2013年 | 2086篇 |
2012年 | 3161篇 |
2011年 | 3079篇 |
2010年 | 1727篇 |
2009年 | 1477篇 |
2008年 | 2248篇 |
2007年 | 2319篇 |
2006年 | 2046篇 |
2005年 | 1812篇 |
2004年 | 1654篇 |
2003年 | 1368篇 |
2002年 | 1192篇 |
2001年 | 372篇 |
2000年 | 319篇 |
1999年 | 291篇 |
1998年 | 206篇 |
1997年 | 133篇 |
1996年 | 147篇 |
1995年 | 108篇 |
1994年 | 97篇 |
1993年 | 79篇 |
1992年 | 148篇 |
1991年 | 164篇 |
1990年 | 134篇 |
1989年 | 128篇 |
1988年 | 108篇 |
1987年 | 107篇 |
1986年 | 101篇 |
1985年 | 120篇 |
1984年 | 79篇 |
1983年 | 58篇 |
1982年 | 54篇 |
1981年 | 58篇 |
1980年 | 41篇 |
1979年 | 50篇 |
1978年 | 40篇 |
1975年 | 36篇 |
1974年 | 38篇 |
1973年 | 36篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
S. Samaras S. Ashfield S.F. Ali L.J. Fopp J.R. Benson C.M. Malata 《Journal of plastic, reconstructive & aesthetic surgery》2021,74(5):957-965
IntroductionHormonal therapy with tamoxifen and aromatase inhibitors reduces breast cancer recurrence and mortality but represents a risk factor for thromboembolic events. Therefore, most surgeons discontinue hormonal agents before microvascular surgery and for a variable period thereafter. There are no guidelines regarding when therapy should be stopped (preoperatively) or when it should be resumed (post-operatively). We, therefore, audited our hospital practice with the objective of making recommendations for microvascular breast reconstruction patients.Patients and methodsA review was performed of all free flap breast reconstructions between 2014 and 2019. Patients were classified according to hormone medication status at operation. Timings of drug cessation and recommencement were recorded. Thrombotic events, namely flap microvascular thrombosis, deep vein thrombosis, superficial vein thrombosis and pulmonary embolism, were compared.ResultsA total of 240 patients had 275 free flaps over five years with 36 receiving hormone therapy within one month prior to surgery, which was discontinued 8.5 days (range: 0–28 days) before surgery. Intraoperative microvascular thromboses (HT 2.0%, NHT 0%, and p = 0.869) and post-operative microvascular complications/flap re-explorations (HT 6.6%, NHT 0%, and p = 0.234) were comparable between the two groups. Systemic venous thromboembolic events were also similar (HT 8.3%, NHT 6.1%, and p = 0.893). Age, BMI, smoking status and preoperative chemotherapy did not influence the incidence of thrombotic complications.ConclusionHormone therapy did not significantly increase the risk of thromboembolic events. Despite the widespread practice of withholding it for 2 weeks prior to reconstructive surgery, this study does not support such practice being beneficial in terms of thromboembolic events and flap viability. Large-scale trials are needed to establish definitive protocols. 相似文献
132.
Shela Akbar Ali Hirani Megan Pearce Amanda Lanoway 《Canadian journal of public health. Revue canadienne de santé publique》2021,112(4):599
SettingThis knowledge mobilization project was conceptualized to increase awareness among breastfeeding mothers and the general public on safe infant feeding practices during the COVID-19 pandemic by addressing myths and misconceptions associated with breastfeeding practices, guiding breastfeeding mothers to make informed decisions around child feeding practices, and offering meaningful guidance in simple language through a short online animated video.InterventionThis project was undertaken in four phases. During phase 1, an informal discussion was held with the breastfeeding mothers, service providers, and community partner in identifying issues surrounding lactation counselling facilities during the COVID-19 pandemic. During phase 2, recommendations from 23 organizations with regard to breastfeeding during COVID-19 were reviewed and analyzed. During phase 3, using evidence from reliable sources, a 5-minute animated e-resource on breastfeeding during COVID-19 was conceptualized and developed. During phase 4, the e-resource was disseminated to the breastfeeding mothers, general public, post-secondary institutions, and organizations providing services to breastfeeding mothers in Canada.OutcomesThis evidence-based e-resource facilitated addressing misconceptions around breastfeeding during COVID-19 and raising public awareness on safe infant feeding practices during this pandemic. Overall, the video was described as an informative, user-friendly, useful, and easily accessible resource by breastfeeding mothers who were in self-isolation with little access to healthcare services during the pandemic.ImplicationsThis project highlighted the importance of patient engagement and collaboration with the community partner in protecting breastfeeding during the COVID-19 pandemic. It further illustrated how informational e-resources can protect breastfeeding in situations where breastfeeding mothers’ access to healthcare services is compromised. 相似文献
133.
Muhammad Ittefaq Annalise Baines Mauryne Abwao Sayyed Fawad Ali Shah Tayyab Ramzan 《Vaccine》2021,39(3):480-486
IntroductionPolio, which is caused by poliovirus, is a contagious, potentially crippling, and deadly disease. Pakistan is one of the countries in which polio is still endemic in the 21st century. In 2019, 146 polio cases were reported across the country with some resulting in deaths. Following the spread of rumors insinuating that children were falling sick after receiving an anti-polio vaccine, a mob attacked and set fire to a small hospital in the Peshawar district in April 2019. The present study investigates readers’ discussions that emerged from Dawn’s online readers’ comments on polio-related news stories in Pakistan.MethodsUsing thematic analysis, we analyzed (N = 2216) comments made by readers in the polio-related news stories published on Dawn.com from January 1, 2012, to March 1, 2020.ResultsSeven major themes emerged from the analysis of the comments: 1) reasons for and challenges resulting in the failure to eradicate polio; 2) proposed solutions and policy changes to eradicate polio; 3) misinformation; 4) criticism, frustration, and shame; 5) comparison of Pakistan to other countries; 6) the internet as a public sphere; 7) suffering, empathy, and appreciation. Overall, our findings suggested that commenters are knowledgeable about polio vaccines and consider polio a serious threat to public health in Pakistan.ConclusionOur study not only validated previous study findings such as reasons, challenges, and issues related to polio vaccination, but also found new challenges in online news sites concerning misinformation on polio and polio vaccination in Pakistan. 相似文献
134.
Abd Elfattah Ali Harb Fatma H. Mostafa Saoud A. Metwally 《Archives of pharmacal research》1990,13(2):187-191
A convenient method for the preparation of imidazobenzimidazole3, imidazoimidazole5, imidazotriazole6 and pyrano [2, 3-c] oxazole7 derivatives is described. This depends on interaction of 2-methyl-4-arylidene-2-oxazolin-5-ones1 with o-diamines, thiosemicarbazide and/or ethylcyanoacetate. The effect of alcoholic potassium cyanide on oxazolinone1 was studied. Antibacterial activity of the obtained products was studied. 相似文献
135.
Chest pain with nondiagnostic electrocardiogram in the emergency department: a randomized controlled trial of two cardiac marker regimens 总被引:3,自引:0,他引:3 下载免费PDF全文
E Dagnone C Collier W Pickett N Ali M Miller D Tod R Morton 《Canadian Medical Association journal》2000,162(11):1561-1566
BACKGROUND: Early detection of acute myocardial infarction (AMI) may save lives. In the emergency setting, it is unclear whether the early use of certain cardiac markers (myoglobin and cardiac troponin I [cTnI]) assists in making appropriate decisions whether to admit or discharge patients with chest pain of possible ischemic cause who have nondiagnostic electrocardiograms (ECGs). We performed a study to determine whether the addition of new cardiac markers in the emergency department results in improved clinical decisions. METHODS: A single-blind randomized controlled trial was conducted between June 1997 and June 1998 in a tertiary care emergency department in Kingston, Ont. Of 296 patients aged 30 years or more who presented to the emergency department with chest pain and nondiagnostic ECGs, 146 were randomly assigned to the intervention group (determination of baseline creatine kinase [CK] level, CK MB fraction and cTnI level, and myoglobin level at baseline and at 2 hours) and 150 to the control group (determination of baseline CK level and CK MB fraction). Outcome measures included the rate of admission to the inpatient cardiology service and length of stay in the emergency department. RESULTS: Of the 296 patients, 34 (11.5%) received a diagnosis of AMI in the emergency department, and 92 (31.1%) had chest pain of noncardiac cause. Patients in the intervention group were less likely than those in the control group to be admitted to the cardiology service (67 [45.9%] v. 81 [54.0%]). The absolute difference in the proportion (8.1% [95% confidence interval -3.3 to 19.5]), although potentially important clinically, was not statistically significant. The length of stay in the emergency department was essentially the same in the 2 study groups. At 30 days, the proportions of patients with a diagnosis of recurrent angina (58.2% in the intervention group and 58.0% in the control group) and AMI (12.3% and 14.7%) were also similar. INTERPRETATION: The optimal cardiac marker panel to be used in the emergency department remains unknown. The addition of serial testing of myoglobin with cTnI confirmation to the standard panel did not substantially change the clinical management or outcomes of patients presenting with chest pain and nondiagnostic ECGs. 相似文献
136.
Alexandra Schneider-Chaabane David Boschert Sibylle Rau Diana Lorena Guevara Solarte Vera Bleicher Ali Al-Ahmad Karen Lienkamp 《Macromolecular chemistry and physics.》2023,224(5):2200323
Facially amphiphilic polymers carrying cationic and hydrophobic groups on the same repeat unit have shown promising antimicrobial activity and biocompatibility, yet they are prone to suffer from protein adhesion which may induce biofilm formation. To overcome this problem, poly(diitaconate)-based copolymers with cationic/hydrophobic and protein-repellent/charge-neutral repeat units are synthesized. The bioactivity profile of surface-attached polymer networks made from these copolymers depends on the ratio of the cationic and charge-neutral repeat units. In all cases, the protein adhesion is substantially reduced compared to purely cationic polymers. At a 50:50 ratio, the polymer coatings are partially protein-repellent and antimicrobial, yet slightly cell toxic. At an intermediate composition of 30:70, they are still antimicrobial and the cell compatibility is substantially improved. The long-term stability of these materials still has to be determined to judge their suitability for medical applications. 相似文献
137.
In an open-label, randomized trial using a 3 x 3 Latin square design, single doses of 24 mg of the ACE inhibitor spirapril, or 50 mg hydrochlorothiazide, or their combination were given to 18 healthy male volunteers. No alteration in the area under plasma drug concentration curve (AUC), peak plasma level, time to peak level, or elimination half-life was detected for hydrochlorothiazide, spirapril, or its active metabolite, spiraprilat, during combination therapy. It was concluded that there was no significant effect of spirapril on single-dose kinetics of hydrochlorothiazide, nor of hydrochlorothiazide on single-dose kinetics of spirapril. Significant reductions in systolic blood pressure were noted 2--6 h after either spirapril or combination treatment, but no evidence of any synergistic effect of single-dose effects on blood pressure was seen during combination therapy. 相似文献
138.
A strategy for reducing maternal mortality 总被引:3,自引:0,他引:3
Suleiman AB Mathews A Jegasothy R Ali R Kandiah N 《Bulletin of the World Health Organization》1999,77(2):190-193
A confidential system of enquiry into maternal mortality was introduced in Malaysia in 1991. The methods used and the findings obtained up to 1994 are reported below and an outline is given of the resulting recommendations and actions. 相似文献
139.
Yui K Goto K Ikemoto S Ishiguro T Angrist B Duncan GE Sheitman BB Lieberman JA Bracha SH Ali SF 《Molecular psychiatry》1999,4(6):512-523
A number of consistent clinical observations provide direction for the hypothesis that pathological sensitization of neuronal systems may be an important factor for relapse or the onset of stimulant-induced psychosis (eg, methamphetamine or amphetamine psychosis, cocaine psychosis and phencyclidine psychosis) and schizophrenia. First, psychotic symptoms can be produced in normal subjects by stimulants. Secondly, a large portion of schizophrenic patients exhibit exacerbation of psychotic symptoms in response to stimulants at doses which would not be psychotogenic in normal subjects. Lastly, the ability of stress to precipitate the onset and relapse of schizophrenia is well documented. In this regard, acute responses to stimulants provide useful information for relapse prediction of schizophrenia and substance abuse. This paper addresses the nature and role of pathological sensitization in relapse of stimulant- and phencyclidine-induced psychosis and schizophrenia, and its relation to pathophysiology of schizophrenia. 相似文献
140.
Ben Ali A 《Presse medicale (Paris, France : 1983)》1999,28(Z3):9-10
CAUSAL GERMS: Over the last 10 years, hemotology units have seen many changes in the epidemiological pattern of infections in neutropenic patients, with a growing number of infections caused by Gram-positive germs. The number of septicemias due to multiresistant Gram-negative germs (Pseudomonas aeruginosa, Strenotrophomonas maltophilia) has however remained high. IMPACT OF THERAPEUTIC REGIMENS: Improved prognosis in neutropenic patients depends for a large part on careful management of septic episodes. As the risk of septicemia is strongly correlated with the degree of efficacy of antibiotic regimens, susceptibility data must always be examined when developing antibiotic protocols in units caring for neutropenic patients. 相似文献