全文获取类型
| 收费全文 | 1481篇 |
| 免费 | 55篇 |
| 国内免费 | 3篇 |
专业分类
| 耳鼻咽喉 | 38篇 |
| 儿科学 | 30篇 |
| 妇产科学 | 34篇 |
| 基础医学 | 227篇 |
| 口腔科学 | 62篇 |
| 临床医学 | 134篇 |
| 内科学 | 377篇 |
| 皮肤病学 | 33篇 |
| 神经病学 | 134篇 |
| 特种医学 | 31篇 |
| 外科学 | 157篇 |
| 综合类 | 2篇 |
| 一般理论 | 1篇 |
| 预防医学 | 107篇 |
| 眼科学 | 11篇 |
| 药学 | 83篇 |
| 中国医学 | 4篇 |
| 肿瘤学 | 74篇 |
出版年
| 2024年 | 10篇 |
| 2023年 | 13篇 |
| 2022年 | 29篇 |
| 2021年 | 54篇 |
| 2020年 | 29篇 |
| 2019年 | 58篇 |
| 2018年 | 58篇 |
| 2017年 | 42篇 |
| 2016年 | 50篇 |
| 2015年 | 52篇 |
| 2014年 | 45篇 |
| 2013年 | 74篇 |
| 2012年 | 125篇 |
| 2011年 | 153篇 |
| 2010年 | 62篇 |
| 2009年 | 71篇 |
| 2008年 | 89篇 |
| 2007年 | 97篇 |
| 2006年 | 64篇 |
| 2005年 | 81篇 |
| 2004年 | 58篇 |
| 2003年 | 58篇 |
| 2002年 | 53篇 |
| 2001年 | 7篇 |
| 2000年 | 10篇 |
| 1999年 | 9篇 |
| 1998年 | 8篇 |
| 1997年 | 4篇 |
| 1996年 | 7篇 |
| 1995年 | 4篇 |
| 1994年 | 2篇 |
| 1993年 | 2篇 |
| 1992年 | 5篇 |
| 1991年 | 8篇 |
| 1990年 | 2篇 |
| 1989年 | 7篇 |
| 1988年 | 4篇 |
| 1985年 | 3篇 |
| 1984年 | 6篇 |
| 1983年 | 3篇 |
| 1982年 | 5篇 |
| 1980年 | 1篇 |
| 1979年 | 2篇 |
| 1978年 | 2篇 |
| 1976年 | 2篇 |
| 1975年 | 2篇 |
| 1974年 | 1篇 |
| 1973年 | 3篇 |
| 1969年 | 1篇 |
| 1967年 | 2篇 |
排序方式： 共有1539条查询结果，搜索用时 15 毫秒
71.
The mycotoxin ochratoxin A (OTA) is a potent nephrocarcinogen, mainly in male rats. The aim of this study was to determine the time course of gene expression (GeneChip® Rat Gene 2.0 ST Array, Affymetrix) in kidney samples from male and female F344 rats, treated daily (p.o) with 0.50 mg/kg b.w. (body weight) of OTA for 7 or 21 days, and evaluate if there were differences between both sexes. After OTA treatment, there was an evolution of gene expression in the kidney over time, with more differentially expressed genes (DEG) at 21 days. The gene expression time course was different between sexes with respect to the number of DEG and the direction of expression (up or down): the female response was progressive and consistent over time, whereas males had a different early response with more DEG, most of them up-regulated. The statistically most significant DEG corresponded to metabolism enzymes (Akr1b7, Akr1c2, Adh6 down-regulated in females; Cyp2c11, Dhrs7, Cyp2d1, Cyp2d5 down-regulated in males) or transporters (Slc17a9 down-regulated in females; Slco1a1 (OATP-1) and Slc51b and Slc22a22 (OAT) down-regulated in males). Some of these genes had also a basal sex difference and were over-expressed in males or females with respect to the other sex. 相似文献
72.
Han G. Yi Bharath Chandrasekaran Kirill V. Nourski Ariane E. Rhone William L. Schuerman Matthew A. Howard III Edward F. Chang Matthew K. Leonard 《Proceedings of the National Academy of Sciences of the United States of America》2021,118(36)
Adults can learn to identify nonnative speech sounds with training, albeit with substantial variability in learning behavior. Increases in behavioral accuracy are associated with increased separability for sound representations in cortical speech areas. However, it remains unclear whether individual auditory neural populations all show the same types of changes with learning, or whether there are heterogeneous encoding patterns. Here, we used high-resolution direct neural recordings to examine local population response patterns, while native English listeners learned to recognize unfamiliar vocal pitch patterns in Mandarin Chinese tones. We found a distributed set of neural populations in bilateral superior temporal gyrus and ventrolateral frontal cortex, where the encoding of Mandarin tones changed throughout training as a function of trial-by-trial accuracy (“learning effect”), including both increases and decreases in the separability of tones. These populations were distinct from populations that showed changes as a function of exposure to the stimuli regardless of trial-by-trial accuracy. These learning effects were driven in part by more variable neural responses to repeated presentations of acoustically identical stimuli. Finally, learning effects could be predicted from speech-evoked activity even before training, suggesting that intrinsic properties of these populations make them amenable to behavior-related changes. Together, these results demonstrate that nonnative speech sound learning involves a wide array of changes in neural representations across a distributed set of brain regions.Humans are finely attuned to the sounds in their native language (1, 2), driven by extensive experience hearing these sounds in many different contexts from different speakers (3–5). However, for nonnative sounds in unfamiliar languages, adult listeners often struggle to learn to recognize relatively simple contrasts (6–9). For example, although native English listeners understand how changes in vocal pitch indicate intonational prosody (e.g., statements versus questions; refs. 10 and 11), this does not translate to the ability to easily identify the syllable-level pitch patterns that define lexical tones in Mandarin Chinese (12, 13). Fundamentally, this difficulty may reflect a trade-off between maintaining stable representations of deeply engrained speech sounds and retaining enough plasticity to be able to continue to learn behaviorally relevant information throughout the lifespan (14–19). Learning to identify nonnative speech sounds often requires long and intense periods of active training (12, 20–22), consistent with the observation that speech circuits in the human brain are resistant to change following developmental critical periods (15, 17).However, even brief training periods can lead to an increased ability to identify novel speech sounds, albeit with highly variable performance across individuals (23–25). Behavioral evidence has further shown that the way listeners perceive relevant auditory cues changes after speech training (14, 25–27), which has led to the hypothesis that learning is rooted in more distinct neural representations of those sounds (17, 27). Consistent with this hypothesis, previous neuroimaging studies have shown that activation in frontotemporal areas increases following identification or discrimination tasks (13, 19, 28–30). These increases in the magnitude of activation are further associated with greater neural separability among sound categories for both speech (31–33) and nonspeech sounds (34–36). However, recent evidence suggests a highly diverse set of speech representations even within areas like the superior temporal gyrus (STG; ref. 37). Currently, the extent to which learning-related changes vary at the level of local populations remains unknown due to the broad spatial scale of noninvasive methods, which may obscure more complex dynamics. In addition, it is unclear how learning-related changes evolve on a trial-by-trial basis, as listeners initially learn to use the stimulus dimensions that allow them to achieve increased accuracy on the task, since most previous work examines neural activity only at early and late stages of the task.Here, we examined the relationship between behavioral performance during the initial stage of nonnative speech sound learning and the trial-by-trial encoding of speech content in local neural populations in the human brain. English-speaking participants listened to unfamiliar Mandarin syllables and learned to identify tone categories (22, 38), while neural activity was recorded from electrocorticography (ECoG) arrays placed over lateral cortical areas. We hypothesized that, as listeners heard the same stimuli across multiple exposures, some neural populations would show responses to Mandarin speech sounds that track the trial-by-trial fluctuations in participants’ behavioral performance during learning, and we also asked whether these changes would be uniformly reflected in increased separability among tones. We further hypothesized that these learning-related neural populations would be distinct from other potential patterns of change across trials that do not directly correlate with learning (e.g., the number of exposures to a given token, independent from accuracy) and neural populations that show stable activity patterns across trials. To address the relationship to stimulus feature encoding (e.g., pitch representations for English intonational prosody; ref. 39), we also measured the extent to which neural responses to unfamiliar Mandarin speech sounds prior to training can be used to predict the emergence of learning-related changes during training.We found a subset of local populations across the cortical surface that track trial-by-trial accuracy, even when learning performance is relatively low and variable. These learning-related effects manifest as both increases and decreases in the amplitude of neural responses to specific speech sounds and are spatially interspersed and dissociable from those that arise simply as a function of repeated exposure. Furthermore, learning-related changes are associated with higher variability of the response amplitude across repeated exposures to the same acoustic stimulus, suggesting less robust emergent neural representations. Finally, we show that intrinsic properties of these neural populations are associated with whether they show learning-related effects during training, allowing us to predict whether these effects will occur based on responses to the novel speech sounds prior to training. Together, these results demonstrate that learning to identify novel speech sounds scaffolds on existing sensitivities to relevant features and that the initial stages of learning a new language involve a specific set of processes to fine-tune local speech representations in the brain. We propose that the learning-induced increased neural separability in frontotemporal regions arises from heterogeneous changes among local populations, which comprise those regions. 相似文献
73.
Amy L. Schneider Candace T. Myers Alison M. Muir Sophie Calvert Alice Basinger M. Scott Perry Lance Rodan Katherine L. Helbig Chelsea Chambers Kathleen M. Gorman Mary D. King Sandra Donkervoort Ariane Soldatos Carsten G. Bnnemann Nino Spataro Elisabeth Gabau Montserrat Arellano Gerarda Cappuccio Nicola Brunetti‐Pierri Elsa Rossignol Fadi F. Hamdan Jacques L. Michaud Christopher Balak Heather C. Mefford Ingrid E. Scheffer 《Epilepsia》2021,62(1):e13-e21
Chromosome 1q41‐q42 deletion syndrome is a rare cause of intellectual disability, seizures, dysmorphology, and multiple anomalies. Two genes in the 1q41‐q42 microdeletion, WDR26 and FBXO28, have been implicated in monogenic disease. Patients with WDR26 encephalopathy overlap clinically with those with 1q41‐q42 deletion syndrome, whereas only one patient with FBXO28 encephalopathy has been described. Seizures are a prominent feature of 1q41‐q42 deletion syndrome; therefore, we hypothesized that pathogenic FBXO28 variants cause developmental and epileptic encephalopathies (DEEs). We describe nine new patients with FBXO28 pathogenic variants (four missense, including one recurrent, three nonsense, and one frameshift) and analyze all 10 known cases to delineate the phenotypic spectrum. All patients had epilepsy and 9 of 10 had DEE, including infantile spasms (3) and a progressive myoclonic epilepsy (1). Median age at seizure onset was 22.5 months (range 8 months to 5 years). Nine of 10 patients had intellectual disability, which was profound in six of nine and severe in three of nine. Movement disorders occurred in eight of 10 patients, six of 10 had hypotonia, four of 10 had acquired microcephaly, and five of 10 had dysmorphic features, albeit different to those typically seen in 1q41‐q42 deletion syndrome and WDR26 encephalopathy. We distinguish FBXO28 encephalopathy from both of these disorders with more severe intellectual impairment, drug‐resistant epilepsy, and hyperkinetic movement disorders. 相似文献
74.
Ariane Orosz Andrea Federspiel Anne Eckert Christian Seeher Thomas Dierks Armita Tschitsaz Katja Cattapan 《Clinical psychology & psychotherapy》2021,28(4):852-861
The increasing prevalence of stress-related disorders such as burnout urges the need for specialized treatment approaches. Programmes combining psychotherapy and regenerative interventions emerge to be the most successful. However, evaluated therapy programmes are scarce and usually involve subjective symptom quantification without consideration of physiologic parameters. The aim of the present exploratory, single-group study was the multimodal investigation of the effectiveness of a specialized holistic therapy programme by assessing symptoms and biological markers of chronic stress. Seventy-one in-patients (39 men/32 women; age 46.8 ± 9.9 years) of a specialized burnout ward with the additional diagnosis of burnout (Z73.0) in conjunction with a main diagnosis of depressive disorder (F32 or F33) according to the International Classification of Diseases (ICD)-10 were included in the study. In addition to symptomatology, the stress-responsive biomarkers heart rate variability (HRV) and serum brain-derived neurotrophic factor (BDNF) were measured in patients at admittance to and discharge from the burnout ward applying a 6-week specialized treatment programme. At discharge, patients showed a significant reduction of symptom burden and a significant increase in serum BDNF, while HRV remained unchanged. The findings implicate that the therapy programme may have beneficial effects on symptomatology and neuroplasticity of patients with burnout. As therapy was often supplemented by psychopharmacological treatment, a relevant influence of antidepressant medication especially on BDNF has to be considered. 相似文献
75.
Ariane Sampson Daniel S. F. Figueiredo Huw G. Jeremiah Dauro D. Oliveira Laize R. P. Freitas Michele Chahoud Rodrigo V. Soares Martyn T. Cobourne 《The Angle orthodontist》2021,91(3):363
ObjectivesTo investigate the relationship between the use of social networking sites (SNSs) on patient perceptions, acceptance, and expectations of treatment using temporary anchorage devices (TADs) and to compare differences between patients from the United Kingdom and Brazil.Materials and MethodsCross-sectional questionnaires were administered to 39 participants at orthodontic practices in the United Kingdom and Brazil about patients'' use of SNSs, exposure to TADs on SNSs, and thoughts on extractions, jaw surgery, or TADs as treatment options.ResultsUK patients prefer for clinicians to have SNS profiles (P = .022). Most UK and Brazilian patients want to see their clinician''s work online (76.7%) and use SNSs to get information about treatment options (76.6%). There was a statistically significant difference in Brazilian patients'' acceptance of TADs as a treatment option compared with UK patients, particularly if it meant avoiding extractions (P = .002), avoiding jaw surgery (P = .004), or reducing treatment time (P = .010). Knowledge of TADs was greater in Brazilian patients (P < .001).ConclusionsPatients use SNSs to obtain information about treatments and prefer clinicians to have social media accounts. Patients exposed to TADs on SNSs are more likely to accept them as an orthodontic treatment option. UK patients have less knowledge of TADs and are therefore less sure to consider TADs as an option. Brazilian patients are more confident in considering the use of TADs. Clinicians should consider increasing their social media presence to accommodate patients'' expectations and acceptance of TADs. 相似文献
76.
Rodrigo S. Carraro Guilherme A. Nogueira Davi Sidarta-Oliveira Rodrigo S. Gaspar Nathalia R. Dragano Joseane Morari Vanessa C. D. Bobbo Eliana P. Araujo Natalia F. Mendes Ariane M. Zanesco Natalia Tobar Celso D. Ramos Jssica M. Toscaro Marcio C. Bajgelman Licio A. Velloso 《The Journal of neuroscience》2021,41(48):10004
77.
78.
79.
Validity of a three-dimensional public-domain system for contemporary endodontic research 总被引：2，自引：0，他引：2
The purpose of this study was to evaluate the limits and benefits of a visualization system based on public-domain software for contemporary three-dimensional (3-D) endodontic research purposes. Three-dimensional bio-models of six human teeth and of one bone-implant specimen were generated using cross-sectional imaging. To evaluate the overall performance in processing large data sets and in reproducing accurate 3-D morphology, slices with a thickness varying from 100 microm to 10 microm were cut. Auto-outlining and segmenting techniques were tested. The 3-D bio-models represented in accurate detail the different morphological aspects of the specimen. Voxel volumes of 0.116 x 10(-5) mm3 could be realized and were only restricted by the computer hardware limitations. The system is not limited to dental hard tissues. Hypomineralized material and soft tissues as well as bone- and allogeneic-implant material could be visualized. The method presented is valid and meets current requirements applying to endodontic research. The broad-based use of high-quality, public-domain software and the resulting exchange of experience help to manage resources and may contribute to enhancing the in-process quality of research. 相似文献
80.