全文获取类型
收费全文 | 137501篇 |
免费 | 8568篇 |
国内免费 | 2917篇 |
专业分类
耳鼻咽喉 | 1747篇 |
儿科学 | 3112篇 |
妇产科学 | 4346篇 |
基础医学 | 20501篇 |
口腔科学 | 3817篇 |
临床医学 | 11535篇 |
内科学 | 24899篇 |
皮肤病学 | 2617篇 |
神经病学 | 8901篇 |
特种医学 | 4723篇 |
外国民族医学 | 14篇 |
外科学 | 18726篇 |
综合类 | 8279篇 |
一般理论 | 36篇 |
预防医学 | 9731篇 |
眼科学 | 3371篇 |
药学 | 12165篇 |
15篇 | |
中国医学 | 1768篇 |
肿瘤学 | 8683篇 |
出版年
2022年 | 1234篇 |
2021年 | 1931篇 |
2020年 | 1249篇 |
2019年 | 1690篇 |
2018年 | 2316篇 |
2017年 | 1730篇 |
2016年 | 1792篇 |
2015年 | 2280篇 |
2014年 | 2918篇 |
2013年 | 3293篇 |
2012年 | 4890篇 |
2011年 | 5277篇 |
2010年 | 3129篇 |
2009年 | 2759篇 |
2008年 | 4409篇 |
2007年 | 4601篇 |
2006年 | 4555篇 |
2005年 | 4109篇 |
2004年 | 3608篇 |
2003年 | 3349篇 |
2002年 | 3135篇 |
2001年 | 7150篇 |
2000年 | 7377篇 |
1999年 | 6129篇 |
1998年 | 2158篇 |
1997年 | 1668篇 |
1996年 | 1204篇 |
1995年 | 1120篇 |
1992年 | 3879篇 |
1991年 | 3946篇 |
1990年 | 3663篇 |
1989年 | 3652篇 |
1988年 | 3516篇 |
1987年 | 3353篇 |
1986年 | 3169篇 |
1985年 | 3017篇 |
1984年 | 2071篇 |
1983年 | 1810篇 |
1982年 | 993篇 |
1979年 | 1916篇 |
1978年 | 1191篇 |
1977年 | 989篇 |
1975年 | 1193篇 |
1974年 | 1360篇 |
1973年 | 1413篇 |
1972年 | 1358篇 |
1971年 | 1248篇 |
1970年 | 1138篇 |
1969年 | 1121篇 |
1968年 | 1024篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
5.
6.
Yosuke Homma Takashi Shiga Hiraku Funakoshi Dai Miyazaki Atsushi Sakurai Yoshio Tahara Ken Nagao Naohiro Yonemoto Arino Yaguchi Naoto Morimura 《The American journal of emergency medicine》2019,37(2):241-248
Objective
This study assessed the association between the timing of first epinephrine administration (EA) and the neurological outcomes following out-of-hospital cardiac arrests (OHCAs) with both initial shockable and non-shockable rhythms.Methods
This was a post-hoc analysis of a multicenter prospective cohort study (SOS-KANTO 2012), which registered OHCA patients in the Kanto region of Japan from January 2012 to March 2013. We included consecutive adult OHCA patients who received epinephrine. The primary result included 1-month favorable neurological outcomes defined as cerebral performance category (CPC) 1 or 2. Secondary results included 1-month survival and return of spontaneous circulation (ROSC) after arrival at the hospital. Multivariable logistic regression analysis determined the association between delay per minute of the time from call to first EA in both pre- or in-hospital settings and outcomes.Results
Of the 16,452 patients, 9344 were eligible for our analyses. In univariable analysis, the delay in EA was associated with decreased favorable neurological outcomes only when the initial rhythm was a non-shockable rhythm. In multivariable analyses, delay in EA was associated with decreased ROSC (adjusted odds ratio [OR] for one minute delay, 0.97; 95% confidence interval [CI], 0.96–0.98) and 1-month survival (adjusted OR, 0.95; 95% CI, 0.92–0.97) when the initial rhythm was a non-shockable rhythm, whereas during a shockable rhythm, delay in EA was not associated with decreased ROSC and 1-month survival.Conclusions
While assessing the effectiveness of epinephrine for OHCA, we should consider the time-limited effects of epinephrine. Additionally, consideration of early EA based on the pathophysiology is needed. 相似文献7.
8.
9.
J. Yang S. Gohel Z. Zhang V. Hatzoglou A.I. Holodny B.A. Vachha 《AJNR. American journal of neuroradiology》2021,42(3):551
BACKGROUND AND PURPOSE:Cognitive challenges are prevalent in survivors of glioma, but their neurobiology is incompletely understood. The purpose of this study was to investigate the effect of glioma presence and tumor characteristics on resting-state functional connectivity and amplitude of low-frequency fluctuations of the salience network, a key neural network associated with cognition.MATERIALS AND METHODS:Sixty-nine patients with glioma (mean age, 48.74 [SD, 14.32] years) who underwent resting-state fMRI were compared with 31 healthy controls (mean age, 49.68 [SD, 15.54] years). We identified 4 salience network ROIs: left/right dorsal anterior cingulate cortex and left/right anterior insula. Average salience network resting-state functional connectivity and amplitude of low-frequency fluctuations within the 4 salience network ROIs were computed.RESULTS:Patients with gliomas showed decreased overall salience network resting-state functional connectivity (P = .001) and increased amplitude of low-frequency fluctuations in all salience network ROIs (P < .01) except in the left dorsal anterior cingulate cortex. Compared with controls, patients with left-sided gliomas showed increased amplitude of low-frequency fluctuations in the right dorsal anterior cingulate cortex (P = .002) and right anterior insula (P < .001), and patients with right-sided gliomas showed increased amplitude of low-frequency fluctuations in the left anterior insula (P = .002). Anterior tumors were associated with decreased salience network resting-state functional connectivity (P < .001) and increased amplitude of low-frequency fluctuations in the right anterior insula, left anterior insula, and right dorsal anterior cingulate cortex. Patients with high-grade gliomas had decreased salience network resting-state functional connectivity compared with healthy controls (P < .05). The right anterior insula showed increased amplitude of low-frequency fluctuations in patients with grade II and IV gliomas compared with controls (P < .01).CONCLUSIONS:By demonstrating decreased resting-state functional connectivity and an increased amplitude of low-frequency fluctuations related to the salience network in patients with glioma, this study adds to our understanding of the neurobiology underpinning observable cognitive deficits in these patients. In addition to more conventional functional connectivity, amplitude of low-frequency fluctuations is a promising functional-imaging biomarker of tumor-induced vascular and neural pathology.Detrimental effects of cancer on cognitive function and, consequently, on the quality of life are emerging as a key focus of cancer survivorship both in research and clinical practice.1,2 Brain tumors have been shown to affect memory, processing, and attention in patients; however, their underlying neurobiology is incompletely understood.3 Using resting-state functional MR imaging (rsfMRI) to evaluate changes in cognitive resting-state networks may provide a better understanding of the pathology underlying the observable cognitive disruptions in gliomas, the most common primary brain tumor in adults.A “triple network model” of neurocognitive pathology has been proposed, which encompasses the default mode network, involved in mind wandering; the central executive network, involved in decision-making; and the salience network (SN), implicated in modulating activation of the default mode network and central executive network by detecting the presence of salient stimuli.4-8 While previous rsfMRI research has largely focused on tumor-induced changes in the default mode network,9,10 our study examined the less-studied SN, a network rooted in the anterior insula and the dorsal anterior cingulate cortex.6Prior studies evaluating gliomas and SN resting-state functional connectivity (RSFC) provided conflicting results in small patient samples: Maesawa et al10 found no significant differences in the SN in 12 patients, while Liu et al11 more recently found decreased SN connectivity in 13 patients. Gliomas impact the integrity of the neurovascular unit to varying degrees, resulting in neurovascular uncoupling that has been reported to confound fMRI interpretations in patients with brain tumors.12-14 Additionally, research has reported neuronal plasticity manifested by structural reorganization and functional remodeling of neural networks in patients with gliomas with possible alterations in clinically observable cognitive manifestations.15-17 An rsfMRI metric, the amplitude of low-frequency fluctuations (ALFF), has recently shown promise as a biomarker for brain plasticity and hemodynamic characterization, including neurovascular uncoupling in patients with gliomas.15-19The purpose of this study was to investigate the effect of glioma presence and tumor characteristics on overall RSFC and regional normalized ALFF within the SN in a large patient population. We hypothesized that there would be decreased average SN RSFC and altered ALFF in patients with gliomas compared with healthy controls. Recent studies have acknowledged that gliomas have variable effects on network integrity based on lesion location and proximity to network ROIs,20-22 and unilateral gliomas can be associated with plasticity in both the ipsilateral and contralateral hemispheres.11,17 Research also supports differences in resting-state network reorganization in aggressive high-grade gliomas compared with slower-growing low-grade gliomas.20,23 Therefore, we also hypothesized that there would be differences in average SN RSFC and regional ALFF in patients based on the anterior-versus-posterior location, hemispheric side, and grade of glioma. 相似文献
10.