全文获取类型
收费全文 | 3221篇 |
免费 | 243篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 28篇 |
儿科学 | 164篇 |
妇产科学 | 84篇 |
基础医学 | 396篇 |
口腔科学 | 124篇 |
临床医学 | 273篇 |
内科学 | 679篇 |
皮肤病学 | 37篇 |
神经病学 | 216篇 |
特种医学 | 307篇 |
外科学 | 395篇 |
综合类 | 98篇 |
一般理论 | 2篇 |
预防医学 | 276篇 |
眼科学 | 80篇 |
药学 | 140篇 |
中国医学 | 23篇 |
肿瘤学 | 154篇 |
出版年
2022年 | 26篇 |
2021年 | 37篇 |
2020年 | 31篇 |
2019年 | 46篇 |
2018年 | 62篇 |
2017年 | 48篇 |
2016年 | 43篇 |
2015年 | 66篇 |
2014年 | 93篇 |
2013年 | 145篇 |
2012年 | 144篇 |
2011年 | 162篇 |
2010年 | 124篇 |
2009年 | 107篇 |
2008年 | 152篇 |
2007年 | 153篇 |
2006年 | 146篇 |
2005年 | 139篇 |
2004年 | 132篇 |
2003年 | 127篇 |
2002年 | 112篇 |
2001年 | 59篇 |
2000年 | 63篇 |
1999年 | 59篇 |
1998年 | 109篇 |
1997年 | 76篇 |
1996年 | 81篇 |
1995年 | 60篇 |
1994年 | 62篇 |
1993年 | 51篇 |
1992年 | 31篇 |
1991年 | 34篇 |
1990年 | 37篇 |
1989年 | 63篇 |
1988年 | 54篇 |
1987年 | 52篇 |
1986年 | 40篇 |
1985年 | 37篇 |
1984年 | 46篇 |
1983年 | 32篇 |
1982年 | 31篇 |
1981年 | 36篇 |
1980年 | 26篇 |
1979年 | 24篇 |
1978年 | 28篇 |
1977年 | 31篇 |
1976年 | 18篇 |
1975年 | 27篇 |
1974年 | 16篇 |
1973年 | 14篇 |
排序方式: 共有3476条查询结果,搜索用时 9 毫秒
31.
32.
The incidence of abnormal morphology and nucleocytoplasmic ratios in 2-, 3- and 5-day human pre-embryos 总被引:3,自引:7,他引:3
N J Winston P R Braude S J Pickering M A George A Cant J Currie M H Johnson 《Human reproduction (Oxford, England)》1991,6(1):17-24
Human cleaving pre-embryos at 2 and 3 days and cavitated pre-embryos at 5 days post-insemination have been examined for cell number and the incidence of mononucleated cells. At least 60% of polynucleate or anucleate cells have been detected at all these stages and regardless of morphological grading at day 2. It is concluded that even by the time at which pre-embryo replacement would occur therapeutically, the majority of pre-embryos are unlikely to have full developmental potential. The possible origins of the abnormalities of nucleocytoplasmic ratios are discussed. 相似文献
33.
34.
Tussive effect of a fentanyl bolus 总被引:10,自引:0,他引:10
Wee Thuan Phua Boon Teck Teh Winston Jong Tat Leang Lee William A. Tweed 《Journal canadien d'anesthésie》1991,38(3):330-334
The aim of this study was to investigate the incidence of pre-induction coughing, after an iv bolus of fentanyl. The study sample was 250 ASA physical status I-II patients, scheduled for various elective surgical procedures. The first 100 were randomly allocated to receive 1.5 micrograms.kg-1 fentanyl via a peripheral venous cannula (Group 1), or an equivalent volume of saline (Group 2). Twenty-eight per cent of patients who received fentanyl, but none given saline, coughed within one minute (P less than 0.0001). The second 150 patients were then randomly assigned to three equal pretreatment groups. Group 3 received 0.01 mg.kg-1 atropine iv one minute before fentanyl. Groups 4 and 5 received 0.2 mg.kg-1 morphine im, and 7.5 mg midazolam po, respectively, one hour before fentanyl. Thirty per cent of patients in Group 3, 6% in Group 4, and 40% in Group 5, had a cough response to fentanyl. Fentanyl, when given through a peripheral cannula, provoked cough in a considerable proportion of patients. This was not altered by premedication with atropine or midazolam, but was reduced after morphine (P less than 0.01). Coughing upon induction of anaesthesia is undesirable in some patients, and stimulation of cough by fentanyl in unpremedicated patients may be of clinical importance. 相似文献
35.
OBJECTIVES: To determine the spectrum of N and G genotypes of respiratory syncytial virus (RSV) causing respiratory tract infection and whether particular genotypes are associated with severity of infection. PATIENTS AND METHODS: Nasopharyngeal aspirates (NPAs) were obtained from 114 infants with acute respiratory tract infection due to RSV over two seasons. Viral mRNA was extracted from NPAs or cultured virus, reverse transcribed, and the cDNA amplified by the polymerase chain reaction using primers directed to parts of the N and G gene respectively. Amplicons were separately digested with four different restriction endonucleases for each gene. The fragments were separated by agarose gel, electrophoresis, and the electrophoretic patterns used to assign the various genotypes. Disease severity was assessed as very mild (upper respiratory tract signs only), mild (coryza and signs of lower respiratory tract infection), moderate (requiring nasogastric or intravenous fluids), and severe (requiring oxygen or ventilation). RESULTS: Five of the six known N genotypes were detected, but NP4 and NP2 were found most frequently. There was no association between N genotype and disease severity. Six G (SHL) genotypes were detected. Significantly (p = 0.04) more of the infants infected with the SHL2 genotype had severe or moderate disease. CONCLUSIONS: During the seasonal peaks of RSV respiratory tract infection at least 10 different RSV genotypes cocirculated. While there is no association between N genotypes and disease severity, infection with the SHL2 G genotype appears to result in moderate to severe disease. 相似文献
36.
37.
38.
39.
Emergency department screening for risk for post-traumatic stress disorder among injured children. 下载免费PDF全文
W L Ward-Begnoche M E Aitken R Liggin S H Mullins N Kassam-Adams A Marks F K Winston 《Injury prevention》2006,12(5):323-326
OBJECTIVE: To discuss the successes and challenges associated with the implementation of a post-traumatic stress disorder (PTSD) screening tool in two pediatric emergency departments (ED). METHODS: The STEPP screening tool has been developed previously on an inpatient population of motor vehicle trauma patients. It was applied here to the general ED population at two different pediatric trauma centers. Nurse screeners were trained and a convenience sample of patients with unintentional injuries who met study criteria were screened in the ED. Feedback from nurse screeners was obtained. RESULTS: The process of implementing a screening tool to identify patients and their families significantly at risk for PTSD symptomatology presented some barriers, but overall acceptability of the process was high for both the emergency department staff and the patient. Recommendations for others considering implementation of screening programs in the ED are offered. CONCLUSIONS: Future research using screening protocols in the ED should, in their design, attempt to capitalize on the successes identified in the current protocol and circumvent barriers also encountered. 相似文献
40.
Winston D Prakash Srinivas Marmamula Asha Latha Mettla Jill Keeffe Rohit C Khanna 《Indian journal of ophthalmology》2022,70(6):2131
Purpose:Addressing childhood vision impairment (VI) is one of the main goals of the World Health Organization’s (WHO) combating blindness strategies. The primary aim of this study was to estimate the prevalence of VI, causes, and its risk factors in school children in Krishna district, Andhra Pradesh, India.Methods:Children aged 4–15 years were screened in schools using the 6/12 Snellen optotype by trained community eye health workers, and those who failed the test and those reported or found to have obvious eye conditions were referred to primary (VC), secondary (SC), or tertiary (TC) care centre appropriately, where they underwent a complete eye examination including cycloplegic refraction and fundus examination.Results:A total of 56,988 children were screened, of whom 51.18% were boys. The mean age was 9.69 ± 3.26 years (4–15 years). Overall, 2,802/56,988 (4.92%) children were referred to a VC, of which 632/56,988 (1.11%) required referral to SC/TC. PVA of <6/12 was found in 1.72% (95% confidence interval [CI]: 1.61–1.83). The prevalence of refractive error (corrected and uncorrected) was 2.38% (95% CI: 2.26–2.51) and myopia was 2.17% (95% CI: 2.05–2.29). In multivariable analysis, older children, those in urban schools, private schools, and children with a disability had an increased risk of VI and myopia. Additionally, the risk of myopia was higher among girls than boys. Of those referred and reached SC/TC, 73.64% were due to avoidable causes.Conclusion:Childhood VI prevalence was 1.72% in this region. Uncorrected refractive error (URE) was the major cause of VI in children. Older age, schools in urban locations, private schools, and the presence of disability were associated with the risk of VI among children. 相似文献