全文获取类型
收费全文 | 2367篇 |
免费 | 181篇 |
国内免费 | 16篇 |
学科分类
医药卫生 | 2564篇 |
出版年
2023年 | 27篇 |
2022年 | 16篇 |
2021年 | 66篇 |
2020年 | 51篇 |
2019年 | 71篇 |
2018年 | 83篇 |
2017年 | 71篇 |
2016年 | 75篇 |
2015年 | 68篇 |
2014年 | 94篇 |
2013年 | 114篇 |
2012年 | 204篇 |
2011年 | 187篇 |
2010年 | 115篇 |
2009年 | 85篇 |
2008年 | 126篇 |
2007年 | 139篇 |
2006年 | 137篇 |
2005年 | 145篇 |
2004年 | 136篇 |
2003年 | 113篇 |
2002年 | 101篇 |
2001年 | 16篇 |
2000年 | 18篇 |
1999年 | 30篇 |
1998年 | 23篇 |
1997年 | 15篇 |
1996年 | 14篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 13篇 |
1992年 | 17篇 |
1991年 | 19篇 |
1990年 | 12篇 |
1989年 | 13篇 |
1988年 | 12篇 |
1987年 | 15篇 |
1986年 | 17篇 |
1985年 | 12篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1978年 | 4篇 |
1977年 | 9篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有2564条查询结果,搜索用时 15 毫秒
1.
2.
Susanna Zanutto Chiara Maura Ciniselli Antonino Belfiore Mara Lecchi Enzo Masci Gabriele Delconte Massimo Primignani Giulia Tosetti Marco Dal Fante Linda Fazzini Aldo Airoldi Marcello Vangeli Francesca Turpini Giovanni Giuseppe Rubis Passoni Paolo Viaggi Monica Arena Roberta Ilaria Olimpia Motta Anna Maria Cantù Cristiano Crosta Giuseppe De Roberto Francesca Iannuzzi Andrea Cassinotti Valentina Dall'Olio Laura Tizzoni Gabriella Sozzi Emanuele Meroni Luigi Bisanti Marco Alessandro Pierotti Paolo Verderio Manuela Gariboldi 《International journal of cancer. Journal international du cancer》2020,146(4):1164-1173
Colorectal cancer (CRC) screening programs help diagnose cancer precursors and early cancers and help reduce CRC mortality. However, currently recommended tests, the fecal immunochemical test (FIT) and colonoscopy, have low uptake. There is therefore a pressing need for screening strategies that are minimally invasive and consequently more acceptable to patients, most likely blood based, to increase early CRC identification. MicroRNAs (miRNAs) released from cancer cells are detectable in plasma in a remarkably stable form, making them ideal cancer biomarkers. Using plasma samples from FIT-positive (FIT+) subjects in an Italian CRC screening program, we aimed to identify plasma circulating miRNAs that detect early CRC. miRNAs were initially investigated by quantitative real-time PCR in plasma from 60 FIT+ subjects undergoing colonoscopy at Fondazione IRCCS Istituto Nazionale dei Tumori, then tested on an internal validation cohort (IVC, 201 cases) and finally in a large multicenter prospective series (external validation cohort [EVC], 1121 cases). For each endoscopic lesion (low-grade adenoma [LgA], high-grade adenoma [HgA], cancer lesion [CL]), specific signatures were identified in the IVC and confirmed on the EVC. A two-miRNA-based signature for CL and six-miRNA signatures for LgA and HgA were selected. In a multivariate analysis including sex and age at blood collection, the areas under the receiver operating characteristic curve (95% confidence interval) of the signatures were 0.644 (0.607–0.682), 0.670 (0.626–0.714) and 0.682 (0.580–0.785) for LgA, HgA and CL, respectively. A miRNA-based test could be introduced into the FIT+ workflow of CRC screening programs so as to schedule colonoscopies only for subjects likely to benefit most. 相似文献
3.
4.
Daniel Drake Kathy Dutton Martha Engelke Maura McAuliffe Mary Ann Rose 《Surgery for obesity and related diseases》2005,1(5):462-466
BACKGROUND: Despite increasing numbers of morbidly obese patients admitted to acute care facilities for surgery or treatment of nonsurgical conditions, there is little evidence of the problems nurses face in providing care to these patients. Anecdotal evidence suggests that the care of these patients is more demanding than the care of nonobese patients. The objective of this study was to describe nurses' perceptions of the challenges that they face when caring for morbidly obese patients. METHODS: Focus groups of nurses from a tertiary care facility were convened. A trained facilitator posed questions to the group concerning various aspects of care for morbidly obese patients. Comments of respondents were categorized using NVIVO software. RESULTS: Nurses reported concerns about the increased staffing needs required for care of these patients and the particular challenges of the physical care. Concerns also included the availability, placement, and use of specialized equipment. Room size and the absence of some equipment were also problematic. Finally, nurses perceived safety issues, both for themselves and their patients. CONCLUSIONS: Morbidly obese patients in the acute care setting require specialized nursing care in terms of techniques, levels of staffing required, and the use of specialized equipment. 相似文献
5.
Fierro B. Castiglione M. G. Salemi G. Savettieri G. 《The Italian Journal of Neurological Sciences》1987,8(2):167-169
The case of a myasthenia-like syndrome induced by cardiovascular drugs is reported. The clinical and electrophysiological
features of the case are discussed.
Sommario Viene descritto il caso di una sindrome miastenica indotta da farmaci efficaci sul sistema cardiovascolare. Vengono analizzate e discusse le principali caratteristiche cliniche ed elettrofisiologiche del caso.相似文献
6.
Maura Jones Moyle Susan Ellis Weismer Julia L Evans Mary J Lindstrom 《J. Speech Lang. Hear. Res.》2007,50(2):508-528
PURPOSE: This study examined the longitudinal relationships between lexical and grammatical development in typically developing (TD) and late-talking children for the purposes of testing the single-mechanism account of language acquisition and comparing the developmental trajectories of lexical and grammatical development in late-talking and TD children. METHOD: Participants included 30 children identified as late talkers (LTs) at 2;0 (years;months), and 30 TD children matched on age, nonverbal cognition, socioeconomic status, and gender. Data were collected at 5 points between 2;0 and 5;6. RESULTS: Cross-lagged correlational analyses indicated that TD children showed evidence of bidirectional bootstrapping between lexical and grammatical development between 2;0 and 3;6. Compared with the TD group, LTs exhibited less evidence of syntactic bootstrapping. Linear mixed-effects modeling of language sample data suggested that the relationship between lexical and grammatical growth was similar for the 2 groups. CONCLUSION: Lexical and grammatical development were strongly related in both groups, consistent with the single-mechanism account of language acquisition. The results were mixed in terms of finding longitudinal differences in lexical-grammatical relationships between the TD and late-talking children; however, several analyses suggested that for late-talking children, syntactic growth may be less facilitative of lexical development. 相似文献
7.
The effects of staphylococci-induced experimental wasting disease on the immune response of 1 month old CD1 mice were investigated. Animals were separated into different subgroups in order to study their cellular immune competence. Malnutrition of wasted mice was associated with anorexia, diarrhea and weakness. Footpad-injected splenic cells produced normal graft vs. host (GvH) reactions in the popliteal lymph nodes of F1 hybrids. In other experiments, the SRBC intragastric feeding of wasted mice did not cause a tolerant anti-erythrocyte humoral immune response. Three weeks after the staphylococci injections, convalescent erythrocyte-fed wasted mice exhibited an anti-SRBC PFC production similar to that observed in non-tolerant immunized control healthy mice. In return, healthy SRBC-fed control mice showed the specific attenuation of antibody response characteristics of oral tolerance. Differences were found between the immune competence of the undernourished staphylococci-treated wasted mice and those shown by other authors in protein-depleted mice. 相似文献
8.
In 50 ulnar nerves of healthy subjects, F-wave latency, duration, amplitude and persistence were determined at different frequencies of the antidromic impulse (0.2-0.5-1-2 Hz). The F amplitude and persistence were found significantly increased at higher stimulation rates, suggesting that the frequency of the antidromic impulse influences the motoneuron pool discharges. Individual cross-correlation values (r) obtained for latency and duration, latency and amplitude, amplitude and duration did not show any significant changes at different stimulation rates. 相似文献
9.
10.
Jordi Ortiz Lawrence W. Fitzgerald Maura Charlton Sarah Lane Louis Trevisan Xavier Guitart William Shoemaker Ronald S. Duman Eric J. Nestler 《Synapse (New York, N.Y.)》1995,21(4):289-298
In previous studies, we have demonstrated that chronic administration of morphine or cocaine produces some common biochemical adaptations in the ventral tegmental area (VTA) and nucleus accumbens (NAc), components of the mesolimbic dopamine system implicated in the reinforcing actions of these and other drugs of abuse. Since this neural pathway is also implicated in the reinforcing actions of ethanol, it was of interest to determine whether chronic ethanol exposure results in similar biochemical adaptations. Indeed, as seen for chronic morphine and cocaine treatments, we show here that chronic ethanol treatment increased levels of tyrosine hydroxylase and glial fibrillary acidic protein immunoreactivity, and decreases levels of neurofilament protein immunoreactivity, in the VTA. Also like morphine and cocaine, ethanol increases levels of cyclic AMP-dependent protein kinase activity in the NAc. These actions of ethanol required long-term exposure to the drug, and were in most cases not seen in the substantia nigra or caudate-putamen, components of the nigrostriatal dopamine system studied for comparison. Altered levels of tyrosine hydroxylase in catecholaminergic cells frequently reflect altered states of activation of the cells. Moreover, increasing evidence indicates that ethanol produces many of its acute effects on the brain by regulating NMDA glutamate and GABA receptors. We therefore examined the influence of chronic ethanol treatment on levels of expression of specific glutamate and GABA receptor subunits in the VTA. It was found that long-term, but not short-term, ethanol exposure increased levels of immunoreactivity of the NMDARl subunit, an obligatory component of NMDA glutamate receptors, and of the Glu Rl subunit, a component of many AMPA glutamate receptors; but at the same time, long-term ethanol exposure decreased immunoreactivity levels of the α1 subunit of the GABAA receptor complex. These changes are consistent with an increased state of activation of VTA neurons inferred from the observed increase intyrosine hydroxylase (TH) expression. These results demonstrate that chronic ethanol exposure results in several biochemical adaptations in the mesolimbic dopamine system, which may underlie prominent changes in the structural and functional properties of this neural pathway related to alcohol abuse and alcoholism. © 1995 Wiley-Liss, Inc. 相似文献