全文获取类型
收费全文 | 27190篇 |
免费 | 2213篇 |
国内免费 | 102篇 |
专业分类
耳鼻咽喉 | 226篇 |
儿科学 | 805篇 |
妇产科学 | 841篇 |
基础医学 | 3433篇 |
口腔科学 | 510篇 |
临床医学 | 2990篇 |
内科学 | 5497篇 |
皮肤病学 | 222篇 |
神经病学 | 2479篇 |
特种医学 | 851篇 |
外国民族医学 | 3篇 |
外科学 | 4423篇 |
综合类 | 497篇 |
一般理论 | 25篇 |
预防医学 | 2504篇 |
眼科学 | 629篇 |
药学 | 1975篇 |
中国医学 | 14篇 |
肿瘤学 | 1581篇 |
出版年
2022年 | 221篇 |
2021年 | 428篇 |
2020年 | 296篇 |
2019年 | 467篇 |
2018年 | 571篇 |
2017年 | 379篇 |
2016年 | 442篇 |
2015年 | 518篇 |
2014年 | 755篇 |
2013年 | 1074篇 |
2012年 | 1706篇 |
2011年 | 1797篇 |
2010年 | 1024篇 |
2009年 | 831篇 |
2008年 | 1690篇 |
2007年 | 1922篇 |
2006年 | 1662篇 |
2005年 | 1693篇 |
2004年 | 1708篇 |
2003年 | 1489篇 |
2002年 | 1451篇 |
2001年 | 420篇 |
2000年 | 382篇 |
1999年 | 397篇 |
1998年 | 342篇 |
1997年 | 308篇 |
1996年 | 252篇 |
1995年 | 219篇 |
1994年 | 220篇 |
1993年 | 193篇 |
1992年 | 277篇 |
1991年 | 240篇 |
1990年 | 241篇 |
1989年 | 249篇 |
1988年 | 197篇 |
1987年 | 238篇 |
1986年 | 179篇 |
1985年 | 178篇 |
1984年 | 168篇 |
1983年 | 186篇 |
1982年 | 150篇 |
1981年 | 165篇 |
1980年 | 137篇 |
1979年 | 161篇 |
1978年 | 146篇 |
1977年 | 119篇 |
1976年 | 124篇 |
1975年 | 124篇 |
1973年 | 118篇 |
1972年 | 130篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Conall T. Morgan Brigitte Mueller Varsha Thakur Vitor Guerra Callaghan Jull Luc Mertens Mark Friedberg Fraser Golding Mike Seed Steven E.S. Miner Edgar T. Jaeggi Cedric Manlhiot Lynne E. Nield 《The Canadian journal of cardiology》2019,35(4):453-461
Background
The purpose of the study was to evaluate the association between fetal echocardiographic measurements and the need for intervention (primary coarctation repair, staged coarctation repair, or catheter intervention) in prenatally diagnosed coarctation of the aorta.Methods
A single-centre retrospective cohort study (2005-2015) of 107 fetuses diagnosed with suspected coarctation of the aorta in the setting of an apex-forming left ventricle and antegrade flow across the mitral and aortic valves.Results
Median gestational age at diagnosis was 32 weeks (interquartile range, 23-35 weeks). Fifty-six (52%) did not require any neonatal intervention, 51 patients (48%) underwent a biventricular repair. In univariable analysis, an increase in ascending aorta (AAo) peak Doppler flow velocity (odds ratio [OR], 1.40 [95% confidence interval [CI], 1.05-1.91] per 20 cm/s; P = 0.03) was associated with intervention. No intervention was associated with larger isthmus size (OR, 0.23; P < 0.001), transverse arch diameter (OR, 0.23; P < 0.001), and aortic (OR, 0.72; P = 0.02), mitral (OR, 0.58; P = 0.001), and AAo (OR, 0.53; P < 0.001) z-scores. In multivariable analysis, higher peak AAo Doppler (OR, 2.51 [95% CI, 1.54-4.58] per 20 cm/s; P = 0.001) and younger gestational age at diagnosis (OR, 0.81 [95% CI, 0.70-0.93] per week; P = 0.005) were associated with intervention, whereas a higher AAo z-score (OR, 0.65 [95% CI, 0.43-0.94] per z; P = 0.029) and transverse arch dimension (OR, 0.44 [95% CI, 0.18-0.97]; P = 0.05) decreased the risk of intervention.Conclusions
In prenatally suspected coarctation, the variables associated with intervention comprised smaller AAo and transverse arch size, earlier gestational age at diagnosis, and the additional finding of a higher peak AAo Doppler. 相似文献4.
Keith P. Reber John D. Sivey Matthew Vollmuth Priyansh D. Gujarati 《Journal of labelled compounds & radiopharmaceuticals》2022,65(9):254-263
Parabens are antimicrobial additives found in a wide array of consumer products. However, the halogenated compounds formed from parabens during wastewater disinfection are a potential environmental concern. In order to identify these transformation products and investigate their mechanism of formation, a synthetic route to ethyl parabens labeled with the stable isotope carbon-13 at specific positions within the benzene ring was developed. This efficient two-step procedure starts from commercially available 13C-labeled phenols and involves (1) initial acylation of the phenol via a Houben–Hoesch reaction with trichloroacetonitrile followed by (2) a modified haloform reaction of the resulting trichloromethyl ketone to afford the corresponding 13C-labeled ethyl parabens in 65%–80% overall yield. The scope of the modified haloform reaction was also investigated, allowing for the synthesis of other parabens derived from primary or secondary alcohols, including 13C- and deuterium-labeled esters. In addition, 4-hydroxybenzoic acid can be formed directly from the common trichloromethyl ketone intermediate upon treatment with lithium hydroxide. This protocol complements existing methods for preparing 13C-labeled paraben derivatives and offers the specific advantages of exhibiting complete regioselectivity in the Houben–Hoesch reaction (to form the para-disubstituted product) and avoiding the need for protecting groups in the modified haloform reaction that forms the paraben esters. 相似文献
5.
6.
Mithun Sattur Clayton Korson Fraser Henderson Stephen Kalhorn 《The American journal of emergency medicine》2019,37(5):1005.e1-1005.e2
Occipital spur is an abnormal bony outgrowth of the external occipital protuberance (EOP). We describe an interesting and previously unreported case of fracture of an occipital spur following trauma. Our 20-year-old male patient was treated in the emergency department (ED) and discharged home without complication. Neurosurgical consultation was obtained but is not requisite for these injuries. Greater awareness of this unique presentation may help to expedite future emergency department treatment. 相似文献
7.
8.
Christopher J. Destache David J. Guervil Keith S. Kaye 《International journal of antimicrobial agents》2019,53(5):644-649
Background
The clinical experience of ceftaroline fosamil (CPT-F) therapy for Gram-positive infective endocarditis is reported from CAPTURE, a retrospective study conducted in the USA.Methods
Data, including patient demographics, medical history, risk factors, microbiological aetiology and clinical outcomes, were collected by review of patient charts between September 2013 and February 2015.Results
Patients (n=55) with Gram-positive endocarditis were treated with CPT-F. The most common risk factors were intravascular devices (43.6%), diabetes mellitus (40.0%) and injection drug use (38.2%). The most commonly isolated pathogens were meticillin-resistant Staphylococcus aureus (MRSA; 80%), meticillin-susceptible S. aureus (MSSA; 7.3%) and coagulase-negative staphylococci (7.3%). CPT-F was given as first-line therapy in 7.3% of patients and as second-line or later therapy in 92.7% of patients, and as monotherapy in 41.8% of patients and as concurrent therapy in 58.2% of patients. Clinical success was observed in 82.6% (19/23) of patients treated with CPT-F as monotherapy. In patients treated with CPT-F as first-line therapy or second-line or later therapy, 75.0% (3/4) and 70.6% (36/51) achieved success, respectively. Clinical success was observed in 77.3% (34/44) of patients with MRSA and 25% (1/4) of patients with MSSA. Two patients discontinued treatment with CPT-F due to an adverse event.Conclusions
CPT-F treatment was associated with a high rate of clinical success in patients with Gram-positive infective endocarditis, including those with risk factors and infections caused by MRSA. A high rate of clinical success was observed in patients treated with CPT-F used as first- line therapy or second-line or later therapy, or as monotherapy or in combination with other antibiotics. 相似文献9.
10.
Kalaichelvi Ganesalingam Ann Sanson Vicki Anderson Keith Owen Yeates 《Journal of the International Neuropsychological Society》2006,12(5):609-621
This study examined the impact of childhood traumatic brain injury (TBI) on self-regulation and social and behavioral functioning, and the role of self-regulation as a predictor of children's social and behavioral functioning. Participants included 65 children with moderate to severe TBI and 65 children without TBI, all between 6 and 11 years of age. Self-regulation and social and behavioral functioning were assessed 2 to 5 years following injury. Children with TBI displayed deficits in self-regulation and social and behavioral functioning, after controlling for socioeconomic status (SES), although the magnitude of the deficits was not related to injury severity. Self-regulation accounted for significant variance in children's social and behavioral functioning, after controlling for SES and group membership. Self-regulation may be an important determinant of children's social and behavioral functioning following TBI. 相似文献