全文获取类型
收费全文 | 10266篇 |
免费 | 849篇 |
国内免费 | 198篇 |
专业分类
耳鼻咽喉 | 50篇 |
儿科学 | 279篇 |
妇产科学 | 85篇 |
基础医学 | 1754篇 |
口腔科学 | 102篇 |
临床医学 | 824篇 |
内科学 | 1309篇 |
皮肤病学 | 46篇 |
神经病学 | 1207篇 |
特种医学 | 106篇 |
外科学 | 405篇 |
综合类 | 522篇 |
现状与发展 | 2篇 |
一般理论 | 1篇 |
预防医学 | 1013篇 |
眼科学 | 112篇 |
药学 | 2781篇 |
6篇 | |
中国医学 | 320篇 |
肿瘤学 | 389篇 |
出版年
2024年 | 33篇 |
2023年 | 164篇 |
2022年 | 387篇 |
2021年 | 434篇 |
2020年 | 386篇 |
2019年 | 394篇 |
2018年 | 368篇 |
2017年 | 354篇 |
2016年 | 379篇 |
2015年 | 376篇 |
2014年 | 563篇 |
2013年 | 873篇 |
2012年 | 521篇 |
2011年 | 538篇 |
2010年 | 445篇 |
2009年 | 497篇 |
2008年 | 468篇 |
2007年 | 400篇 |
2006年 | 336篇 |
2005年 | 302篇 |
2004年 | 257篇 |
2003年 | 235篇 |
2002年 | 179篇 |
2001年 | 149篇 |
2000年 | 160篇 |
1999年 | 162篇 |
1998年 | 130篇 |
1997年 | 123篇 |
1996年 | 120篇 |
1995年 | 104篇 |
1994年 | 97篇 |
1993年 | 115篇 |
1992年 | 102篇 |
1991年 | 105篇 |
1990年 | 107篇 |
1989年 | 84篇 |
1988年 | 84篇 |
1987年 | 81篇 |
1986年 | 80篇 |
1985年 | 94篇 |
1984年 | 85篇 |
1983年 | 47篇 |
1982年 | 69篇 |
1981年 | 60篇 |
1980年 | 52篇 |
1979年 | 43篇 |
1978年 | 33篇 |
1977年 | 31篇 |
1976年 | 42篇 |
1975年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This study used a sequential two-phase explanatory design. The first phase of this mixed-methods design aimed to explore conflict resolution strategies in adolescent dating couples, and the second phase to document, from both the perspective of the individual and of the couple, dyadic interaction patterns distinguishing youth inflicting dating violence from those who do not. A sample of 39 heterosexual couples (mean age 17.8 years) participated in semi-structured interviews and were observed during a 45 min dyadic interaction. At phase 1, qualitative analysis revealed three main types of conflict resolution strategies: 1) negotiating expectations and individual needs; 2) avoiding conflicts or their resolution; 3) imposing personal needs and rules through the use of violence. At phase 2, we focused on couples with conflictive patterns. Results indicate that couples who inflict violence differ from nonviolent couples by their tendency to experience conflicts when in disagreement and to resort to negative affects as a resolution strategy. In addition, while at an individual level, they show a tendency to withdraw from conflict and to use less positive affect, at a dyadic level they present less symmetry. Results offer important insights for prevention programs. 相似文献
992.
Brain activity and connectivity in response to negative affective stimuli: Impact of dysphoric mood and sex across diagnoses 下载免费PDF全文
Klara Mareckova Laura M. Holsen Roee Admon Nikos Makris Larry Seidman Stephen Buka Susan Whitfield‐Gabrieli Jill M. Goldstein 《Human brain mapping》2016,37(11):3733-3744
Negative affective stimuli elicit behavioral and neural responses which vary on a continuum from adaptive to maladaptive, yet are typically investigated in a dichotomous manner (healthy controls vs. psychiatric diagnoses). This practice may limit our ability to fully capture variance from acute responses to negative affective stimuli to psychopathology at the extreme end. To address this, we conducted a functional magnetic resonance imaging study to examine the neural responses to negative valence/high arousal and neutral valence/low arousal images as a function of dysphoric mood and sex across individuals (n = 99) who represented traditional categories of healthy controls, major depressive disorder, bipolar psychosis, and schizophrenia. Observation of negative (vs. neutral) stimuli elicited blood oxygen‐level dependent responses in the following circuitry: periaqueductal gray, hypothalamus (HYPO), amygdala (AMYG), hippocampus (HIPP), orbitofrontal cortex (OFC), medial prefrontal cortex (mPFC), and greater connectivity between AMYG and mPFC. Across all subjects, severity of dysphoric mood was associated with hyperactivity of HYPO, and, among females, right (R) AMYG. Females also demonstrated inverse relationships between severity of dysphoric mood and connectivity between HYPO ‐ R OFC, R AMYG ‐ R OFC, and R AMYG ‐ R HIPP. Overall, our findings demonstrated sex‐dependent deficits in response to negative affective stimuli increasing as a function of dysphoric mood state. Females demonstrated greater inability to regulate arousal as mood became more dysphoric. These findings contribute to elucidating biosignatures associated with response to negative stimuli across disorders and suggest the importance of a sex‐dependent lens in determining these biosignatures. Hum Brain Mapp 37:3733–3744, 2016. © 2016 Wiley Periodicals, Inc . 相似文献
993.
Poitras P Riberdy Poitras M Plourde V Boivin M Verrier P 《Digestive diseases and sciences》2002,47(4):914-920
Irritable bowel syndrome (IBS) has been associated with visceral hypersensitivity. Here we examined the evolution of rectal sensitivity and of gastrointestinal symptomatology in IBS patients over time, to verify if the clinical and biological parameters showed parallel behavior. Patients complaining of IBS, identified by Rome 1 criteria, were included in this study. The severity of the gastrointestinal (Gastrointestinal) symptoms was assessed by a gastrointestinal index. The pain threshold to rectal distension was measured by a barostat programmed for phasic ascending distensions. Both measures were obtained before and after treatment. Thirty-nine patients were followed while on a 10-week group psychotherapy (psy) program. Twelve patients were controlled after pharmacological treatment with amitriptyline (Ami) 10 mg hours for two weeks and then 25 mg hours for the following 4 weeks. Clinical improvement with symptom reduction was achieved in both patients groups. With psy, the Gastrointestinal index declined from an initial value of 78.4 ± 4.8 to 65.5 ± 4.5 at the end of treatment (P < 0.05). With Ami, the gastrointestinal index decreased from 91.6 ± 5.6 to 61.8 ± 9.1 (p < 0.01). The pain threshold to rectal distension increased from 27.7 ± 1.0 to 33.7 ± 1.9 mmHg (P < 0.01) after drug treatment, but remained unchanged (30.6 ± 1.0 vs 30.6 ± 1.1 mm Hg) with psy. Evolution of the gastrointestinal index and rectal sensitivity were directly correlated (r = –0.71; P < 0.01) in Ami patients, but not in those treated with Psy (r = –0.001). In conclusion, visceral hypersensitivity appeared as a stable biological defect over a 10- to 12-week period during clinically-effective treatment with psychotherapy. Rectal pain threshold, however, seemed to be pharmacologically manipulatable in patients treated with Ami. 相似文献
994.
Being affected by aphasia influences the total life experience. The aim of this study was to generate a theoretical model, from a nursing perspective, of what aphasic persons (n = 12) experience in encounters with other people. Data were collected through interviews which adopted a biophysical, socio-cultural and psychological approach and then analysed using grounded theory method. Two main categories emerged, namely: 'interaction' and 'support'. Encountered experiences led to: 'a feeling of having ability'; 'a feeling of being an outsider'; and 'a feeling of dejection or uncertainty'. The feeling state was dependent on whether the interaction was 'obstructed' or 'secure' and on whether the support resulted in 'strengthened' or 'impaired' self-esteem. Therefore nurses need to give support that enhances patients' self-esteem and which results in them gaining a positive and realistic view of their aphasia, as well as involving those around them in this perspective. This then will give the possibility for the patient to turn the interaction process from an obstructed into a secure one. 相似文献
995.
Aim This study investigates the determinants of morale among Registered Nurses in Queensland, Australia.
Background In light of the public discussions on the issues facing the future of nursing, it is critical to understand the factors that influence morale.
Methods A 160-question instrument sought information from Registered Nurses on their perceptions of 'self', work and morale. A response rate of 41% was achieved ( n = 343) from a convenience sample of three acute hospitals.
Results Following binary logistic regression modelling for organizational morale, significant relationships were found with patient care provision and team interaction. Binary logistic regression modelling for personal morale revealed positive relationships with team interaction, consultation, professional recognition and lower levels of patient abuse.
Conclusion The results point to a number of organizational and professional issues that can be considered by health care administrators and policy makers to develop workplaces that have a positive impact on the morale of nurses. 相似文献
Background In light of the public discussions on the issues facing the future of nursing, it is critical to understand the factors that influence morale.
Methods A 160-question instrument sought information from Registered Nurses on their perceptions of 'self', work and morale. A response rate of 41% was achieved ( n = 343) from a convenience sample of three acute hospitals.
Results Following binary logistic regression modelling for organizational morale, significant relationships were found with patient care provision and team interaction. Binary logistic regression modelling for personal morale revealed positive relationships with team interaction, consultation, professional recognition and lower levels of patient abuse.
Conclusion The results point to a number of organizational and professional issues that can be considered by health care administrators and policy makers to develop workplaces that have a positive impact on the morale of nurses. 相似文献
996.
Naveen N. Narisetty Bhramar Mukherjee Yin-Hsiu Chen Richard Gonzalez John D. Meeker 《Statistics in medicine》2019,38(9):1582-1600
In this paper, we propose a stepwise forward selection algorithm for detecting the effects of a set of correlated exposures and their interactions on a health outcome of interest when the underlying relationship could potentially be nonlinear. Though the proposed method is very general, our application in this paper remains to be on analysis of multiple pollutants and their interactions. Simultaneous exposure to multiple environmental pollutants could affect human health in a multitude of complex ways. For understanding the health effects of multiple environmental exposures, it is often important to identify and estimate complex interactions among exposures. However, this issue becomes analytically challenging in the presence of potential nonlinearity in the outcome-exposure response surface and a set of correlated exposures. Through simulation studies and analyses of test datasets that were simulated as a part of a data challenge in multipollutant modeling organized by the National Institute of Environmental Health Sciences ( http://www.niehs.nih.gov/about/events/pastmtg/2015/statistical/ ), we illustrate the advantages of our proposed method in comparison with existing alternative approaches. A particular strength of our method is that it demonstrates very low false positives across empirical studies. Our method is also used to analyze a dataset that was released from the Health Outcomes and Measurement of the Environment Study as a benchmark beta-tester dataset as a part of the same workshop. 相似文献
997.
In this article, we consider a semiparametric additive partially linear interaction model for the integrative analysis of multiple genetic datasets. The goals are to identify important genetic predictors and gene-gene interactions and to estimate the nonparametric functions that describe the environmental effects at the same time. To find the similarities and differences of the genetic effects across different datasets, we impose a group structure on the regression coefficients matrix under the homogeneity assumption, ie, models for different datasets share the same sparsity structure, but the coefficients may differ across datasets. We develop an iterative approach to estimate the parameters of main effects, interactions and nonparametric functions, where a reparametrization of interaction parameters is implemented to meet the strong hierarchy assumption. We demonstrate the advantages of the proposed method in identification, estimation, and prediction in a series of numerical studies. We also apply the proposed method to the Skin Cutaneous Melanoma data and the lung cancer data from the Cancer Genome Atlas. 相似文献
998.
How to use nitrates 总被引:2,自引:0,他引:2
Abrams J 《Cardiovascular drugs and therapy / sponsored by the International Society of Cardiovascular Pharmacotherapy》2002,16(6):511-514
Nitrates are old drugs, available in many formulations, that are effective in relieving symptoms in various CAD syndromes as well as congestive heart failure. Nitrate tolerance is the major problem limiting nitrate efficacy and use by physicians. Currently, an intermittent dosing strategy is the only practical way to limit the development of tolerance or attenuation of nitrate actions. 相似文献
999.
Leena Subramanian M.Phil John Vincent Hindle FRCP FRCPsych Margaret Cecilia Jackson David E. J. Linden MD PhD 《Movement disorders》2010,25(16):2792-2799
The influence of emotional context on cognitive operations is of fundamental importance for the evolution of higher cognitive functions and their disturbance in neuropsychiatric disorders. The dopamine pathways projecting to prefrontal cortex and the basal ganglia are assumed to play a major role in such emotion‐cognition interactions. Here we provide evidence for such a role by studying working memory for emotional faces in patients with Parkinson's Disease. We studied 25 patients with Parkinson's disease during their on and off medication states. Faces with emotional expressions (happy, angry, sad, neutral or fearful) were shown and the participants had to remember and later recall the identity of the faces ignoring the expressions. We found that dopaminergic medication enhances working memory for angry faces and suppresses it for sad faces. The results elucidate neurochemical mechanisms for the saliency of threatening information and support cognitive explanations of the antidepressant effects of dopamine. They also suggest a role for dopamine in changing emotional‐cognitive biases rather than as a generic cognitive enhancer. © 2010 Movement Disorder Society. 相似文献
1000.
Vincent D. Costa Peter J. Lang Dean Sabatinelli Francesco Versace Margaret M. Bradley 《Human brain mapping》2010,31(9):1446-1457
Research on emotional perception and learning indicates appetitive cues engage nucleus accumbens (NAc) and medial prefrontal cortex (mPFC), whereas amygdala activity is modulated by the emotional intensity of appetitive and aversive cues. This study sought to determine patterns of functional activation and connectivity among these regions during narrative emotional imagery. Using event‐related fMRI, we investigate activation of these structures when participants vividly imagine pleasant, neutral, and unpleasant scenes. Results indicate that pleasant imagery selectively activates NAc and mPFC, whereas amygdala activation was enhanced during both pleasant and unpleasant imagery. NAc and mPFC activity were each correlated with the rated pleasure of the imagined scenes, while amygdala activity was correlated with rated emotional arousal. Functional connectivity of NAc and mPFC was evident throughout imagery, regardless of hedonic content, while correlated activation of the amygdala with NAc and mPFC was specific to imagining pleasant scenes. These findings provide strong evidence that pleasurable text‐driven imagery engages a core appetitive circuit, including NAc, mPFC, and the amygdala. Hum Brain Mapp, 2010. © 2010 Wiley‐Liss, Inc. 相似文献