全文获取类型
收费全文 | 15590篇 |
免费 | 936篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 398篇 |
妇产科学 | 350篇 |
基础医学 | 2176篇 |
口腔科学 | 240篇 |
临床医学 | 1760篇 |
内科学 | 3037篇 |
皮肤病学 | 142篇 |
神经病学 | 1348篇 |
特种医学 | 949篇 |
外国民族医学 | 2篇 |
外科学 | 1786篇 |
综合类 | 458篇 |
一般理论 | 6篇 |
预防医学 | 1419篇 |
眼科学 | 147篇 |
药学 | 1005篇 |
中国医学 | 13篇 |
肿瘤学 | 1221篇 |
出版年
2023年 | 100篇 |
2022年 | 142篇 |
2021年 | 326篇 |
2020年 | 191篇 |
2019年 | 299篇 |
2018年 | 348篇 |
2017年 | 246篇 |
2016年 | 285篇 |
2015年 | 335篇 |
2014年 | 511篇 |
2013年 | 623篇 |
2012年 | 955篇 |
2011年 | 1000篇 |
2010年 | 497篇 |
2009年 | 476篇 |
2008年 | 917篇 |
2007年 | 915篇 |
2006年 | 886篇 |
2005年 | 827篇 |
2004年 | 795篇 |
2003年 | 695篇 |
2002年 | 690篇 |
2001年 | 463篇 |
2000年 | 424篇 |
1999年 | 343篇 |
1998年 | 172篇 |
1997年 | 154篇 |
1996年 | 111篇 |
1995年 | 99篇 |
1994年 | 66篇 |
1993年 | 62篇 |
1992年 | 177篇 |
1991年 | 182篇 |
1990年 | 160篇 |
1989年 | 180篇 |
1988年 | 147篇 |
1987年 | 136篇 |
1986年 | 114篇 |
1985年 | 129篇 |
1984年 | 99篇 |
1983年 | 76篇 |
1982年 | 56篇 |
1979年 | 100篇 |
1978年 | 55篇 |
1977年 | 54篇 |
1976年 | 59篇 |
1974年 | 78篇 |
1973年 | 70篇 |
1972年 | 65篇 |
1970年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Josh Greenstein Devjani Das Josie Acuna Monica Kapoor Cara Brown Abbas Husain Brendan Lally Barry Hahn 《The American journal of emergency medicine》2019,37(2):313-316
Background
In the emergency department, rib fractures are a common finding in patients who sustain chest trauma. Rib fractures may be a sign of significant, underlying pathology, especially in the elderly patients where rib fractures are associated with significant morbidity and mortality. To date, no studies have evaluated the ability of ultrasound to detect rib fractures using cadaver models and subsequently use this model as a teaching tool.Objectives
The purpose of this study was to determine if it is possible to generate rib fractures on cadaver models which could be accurately identified using ultrasound.Methods
This was a cross-sectional study performed during one session at a cadaver lab. A single hemithorax from four adult cadavers were used as models. Single rib fractures on each of rib five through eight were created. Four subjects, blinded to the normal versus fractured ribs, were asked to identify the presence of a fracture on each rib.Results
A total of 8 of 16 potential ribs had fractured induced by study staff. Mean accuracy was 55% for all subjects. The overall sensitivity and specificity for detecting rib fractures was 50% (CI: 31.89–68.11) and 59.38% (CI: 35.69–73.55) respectively. The overall PPV and NPV was 55.17% and 54.29% respectively.Conclusions
In this pilot study, subjects were not able to detect induced rib fractures using ultrasound on cadaver models. The use of this model as a teaching tool in the detection of rib fractures requires further investigation. 相似文献3.
4.
5.
6.
7.
We have previously reported the time trends, design and interventions in randomised controlled trials (RCTs) in cystic fibrosis (CF) from 1961 through 1997 [Cheng K, Smyth RL, Motley J, O'Hea U, Ashby D, Randomised controlled trials in cystic fibrosis (1966-1997) categorized by time, design, and intervention. Pediatr Pulmonol 2000, 29:1-7.]. We maintain an ongoing register of all RCTs and controlled clinical trials (CCTs) in CF and have noted that in the five years since 1997 there has been a 48% increase in published trials. We aimed to assess whether this increase has been associated with an improvement in design quality. All RCTs and CCTs from 1961-2002 were assessed. Two epochs were then compared, 1961-1997 and 1998-2002. For each trial we recorded the design, participant numbers and the intervention studied. 261 trials in 1998-2002 were compared with 544 trials in 1961-1997. Comparing the two epochs a similar proportion of trials were parallel, double-blind and placebo controlled; also the median number of participants was similar. In the later epoch 25% of trials were multicentre, compared with 11% previously. Whilst this recent increase in clinical trials in CF is welcome, this has not been associated with improvements in quality. The trend for an increasing proportion of trials to be multicentre is encouraging. There are however, still deficiencies in the design of clinical trials in CF. 相似文献
8.
Tracy Brightman Jiang-Hong Ye Elizabeth Ortiz-Jimenez Edward J. Flynn Wen-Hsien Wu Joseph J. McArdle 《Brain research》1995,678(1-2)
While adult mice receiving picrotoxin (PTX) alone responded with clonic and tonic-clonic seizures, this response was greatly suppressed for mice simultaneously injected with 2,3-butanedione monoxime (BDM). For example, 60% and 10% of the mice convulsed when injected (i.p.) with 3.0 mg/kg PTX alone or PTX plus 205 mg/kg of BDM, respectively. In contrast, a non-oxime analogue of BDM, 2,3-butanedione (BTD), did not have this anticonvulsant effect. In order to explore the basis for the anticonvulsant effect of BDM, we recorded GABA-activated currents (IGABA) of frontal cortical as well as ventromedial hypothalamic neurons before, during and after exposure to this oxime. BDM had a biphasic effect on concentrations (100 μM-40 mM) decreased and lower concentrations (0.01 μM–0.001 μM) potentiatedIGABA; these effects of BDM reversed upon washout of the oxime. In contrast, BTD had no effect onIGABA. Finally, when 0.001 μM BDM, 10–30 μM PTX and GABA were co-applied the inhibitory effect of the toxin onIGABA was markedly suppressed. These data suggest that the anticonvulsant effect of oximes involves facilitation of the inhibitory action of GABA. 相似文献
9.
10.
Edward M Messing Judith Manola George Wilding Kathleen Propert Jonathan Fleischmann E David Crawford J Edson Pontes Richard Hahn Donald Trump 《Journal of clinical oncology》2003,21(7):1214-1222
PURPOSE: To evaluate the role of adjuvant interferon alfa after complete resection of locally extensive renal cell carcinoma. PATIENTS AND METHODS: A total of 283 eligible patients with pT3-4a and/or node-positive disease were randomly assigned after radical nephrectomy and lymphadenectomy to observation or to interferon alfa-NL (Wellferon, Burroughs-Wellcome, Research Park, NC) given daily for 5 days every 3 weeks for up to 12 cycles. Patients were stratified on the basis of pathologic stage. Patients remained on treatment until documented recurrence, excessive toxicity, or patient/physician preference deemed removal appropriate. RESULTS: At median follow-up of 10.4 years, median survival was 7.4 years in the observation arm and 5.1 year in the treatment arm (log-rank P =.09). Median recurrence-free survival was 3.0 years in the observation arm and 2.2 years in the interferon arm (P =.33). Performance status (P =.003), nodal status (N2 v N0, P <.0001), and tumor stage (P =.0002) were significant prognostic factors in multivariate analysis. A proportional hazards model examining the effects of treatment arm and time to recurrence on survival after recurrence among patients who recurred found that random assignment to interferon treatment (P =.009) and shorter time to recurrence (P <.0001) were independent predictors of shorter survival after recurrence. Although no lethal toxicities were observed, severe (grade 4) toxicities including neutropenia, myalgia, fatigue, depression, and other neurologic toxicities occurred in 11.4% of those randomly assigned to interferon treatment. CONCLUSION: Adjuvant treatment with interferon did not contribute to survival or relapse-free survival in this group of patients. 相似文献