全文获取类型
收费全文 | 1700篇 |
免费 | 59篇 |
国内免费 | 80篇 |
专业分类
耳鼻咽喉 | 26篇 |
儿科学 | 49篇 |
妇产科学 | 11篇 |
基础医学 | 233篇 |
口腔科学 | 21篇 |
临床医学 | 223篇 |
内科学 | 471篇 |
皮肤病学 | 29篇 |
神经病学 | 140篇 |
特种医学 | 333篇 |
外科学 | 59篇 |
综合类 | 21篇 |
预防医学 | 39篇 |
眼科学 | 34篇 |
药学 | 103篇 |
肿瘤学 | 47篇 |
出版年
2023年 | 9篇 |
2021年 | 4篇 |
2020年 | 12篇 |
2019年 | 13篇 |
2018年 | 16篇 |
2017年 | 10篇 |
2016年 | 21篇 |
2015年 | 18篇 |
2014年 | 28篇 |
2013年 | 36篇 |
2012年 | 45篇 |
2011年 | 36篇 |
2010年 | 46篇 |
2009年 | 55篇 |
2008年 | 51篇 |
2007年 | 95篇 |
2006年 | 44篇 |
2005年 | 72篇 |
2004年 | 57篇 |
2003年 | 72篇 |
2002年 | 66篇 |
2001年 | 76篇 |
2000年 | 51篇 |
1999年 | 63篇 |
1998年 | 74篇 |
1997年 | 79篇 |
1996年 | 52篇 |
1995年 | 70篇 |
1994年 | 41篇 |
1993年 | 43篇 |
1992年 | 30篇 |
1991年 | 34篇 |
1990年 | 29篇 |
1989年 | 43篇 |
1988年 | 43篇 |
1987年 | 34篇 |
1986年 | 31篇 |
1985年 | 48篇 |
1984年 | 25篇 |
1983年 | 21篇 |
1982年 | 28篇 |
1981年 | 16篇 |
1980年 | 26篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 16篇 |
1976年 | 16篇 |
1975年 | 13篇 |
1974年 | 4篇 |
1973年 | 3篇 |
排序方式: 共有1839条查询结果,搜索用时 62 毫秒
51.
Ryan J. Jacoby Rachel C. Leonard Bradley C. Riemann Jonathan S. Abramowitz 《Comprehensive psychiatry》2014
Obsessive–compulsive disorder (OCD) is the 10th leading cause of disability among health conditions; yet, relatively little research has focused on quality of life (QOL) and functional impairment in OCD. The present study extended existing work by examining correlates and predictors of QOL and functional impairment in 96 treatment-seeking OCD patients (in intensive outpatient and residential settings). In a model including OCD symptoms and related phenomena, and symptoms of depression and anxiety, two main findings emerged: (a) depressive symptoms predicted both QOL and functional impairment, and (b) contamination symptoms predicted functional impairment. These findings are discussed in terms of the implications for studying QOL and functional impairment in OCD. Future research should investigate the factors that predict changes in QOL and functional impairment following treatment. 相似文献
52.
53.
Lukas Frase Peter Selhausen Lukas Krone Sulamith Tsodor Friederike Jahn Bernd Feige Jonathan G. Maier Florian Mainberger Hannah Piosczyk Marion Kuhn Stefan Klöppel Annette Sterr Chiara Baglioni Kai Spiegelhalder Dieter Riemann Michael A. Nitsche Christoph Nissen 《Brain stimulation》2019,12(3):674-683
Background
Arousal and sleep represent basic domains of behavior, and alterations are of high clinical importance.Objective/hypothesis
The aim of this study was to further elucidate the neurobiology of insomnia disorder (ID) and the potential for new treatment developments, based on the modulation of cortical activity through the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS). Specifically, we tested the hypotheses that bi-frontal anodal tDCS shortens and cathodal tDCS prolongs total sleep time in patients with ID, compared to sham stimulation. Furthermore, we tested for differences in indices of arousal between ID patients and healthy controls and explored their potential impact on tDCS effects.Methods
Nineteen ID patients underwent a within-subject repeated-measures sleep laboratory study with adaptation, baseline and three experimental nights. Bifrontal anodal, cathodal and sham tDCS was delivered in a counterbalanced order immediately prior to sleep. Wake EEG was recorded prior to and after tDCS as well as on the following morning. Subsequently, we compared patients with ID to a healthy control group from an earlier dataset.Results
Against our hypothesis, we did not observe any tDCS effects on sleep continuity or sleep architecture in patients with ID. Further analyses of nights without stimulation demonstrated significantly increased levels of arousal in ID patients compared to healthy controls, as indexed by subjective reports, reduced total sleep time, increased wake after sleep onset and increased high frequency EEG power during wakefulness and NREM sleep. Of note, indices of increased arousal predicted the lack of effect of tDCS in ID patients.Conclusions
Our study characterizes for the first time differential effects of tDCS on sleep in patients with ID and healthy controls, presumably related to persistent hyperarousal in ID. These findings suggest that adapted tDCS protocols need to be developed to modulate arousal and sleep dependent on baseline arousal levels. 相似文献54.
Lukas Frase Wolfram Regen Stphanie Kass Albena Rambach Chiara Baglioni Bernd Feige Jürgen Hennig Dieter Riemann Christoph Nissen Kai Spiegelhalder 《Journal of sleep research》2020,29(5)
The current study was designed to further clarify the influence of brain morphology, sleep oscillatory activity and age on memory consolidation. Specifically, we hypothesized, that a smaller volume of hippocampus, parahippocampal and medial prefrontal cortex negatively impacts declarative, but not procedural, memory consolidation. Explorative analyses were conducted to demonstrate whether a decrease in slow‐wave activity negatively impacts declarative memory consolidation, and whether these factors mediate age effects on memory consolidation. Thirty‐eight healthy participants underwent an acquisition session in the evening and a retrieval session in the morning after night‐time sleep with polysomnographic monitoring. Declarative memory was assessed with the paired‐associate word list task, while procedural memory was tested using the mirror‐tracing task. All participants underwent high‐resolution magnetic resonance imaging. Participants with smaller hippocampal, parahippocampal and medial prefrontal cortex volumes displayed a reduced overnight declarative, but not procedural memory consolidation. Mediation analyses showed significant age effects on overnight declarative memory consolidation, but no significant mediation effects of brain morphology on this association. Further mediation analyses showed that the effects of age and brain morphology on overnight declarative memory consolidation were not mediated by polysomnographic variables or sleep electroencephalogram spectral power variables. Thus, the results suggest that the association between age, specific brain area volume and overnight memory consolidation is highly relevant, but does not necessarily depend on slow‐wave sleep as previously conceptualized. 相似文献
55.
56.
Andreas Jaehne Thomas Unbehaun Bernd Feige Ulrich C. Lutz Anil Batra Dieter Riemann 《Sleep medicine》2012,13(10):1286-1292
ObjectiveSubjective quality of sleep is impaired in smokers compared with non-smokers, but there is only limited evidence from methodologically sound studies about differences in polysomnography (PSG) sleep characteristics. Therefore, this study used PSG to evaluate sleep in smokers and non-smokers while controlling for other parameters that affect sleep.MethodsAfter an adaptation night, PSG sleep laboratory data were obtained from 44 smokers (29 men and 15 women, median age 29.6 years) and compared with PSG data from 44 healthy, sex- and age-matched never smokers. Exclusion criteria were alcohol or other substance abuse, psychiatric or endocrine diseases, and treatment with any kind of psychotropic medication. Nicotine and cotinine plasma levels were measured (in the smoking group) and subjective sleep quality assessed in both groups.ResultsThe smokers had a Fagerström tolerance score of 6.4, consumed an average of 21.2 cigarettes per day and had been smoking for 13.1 years (median). Smokers had a shorter sleep period time, longer sleep latency, higher rapid eye movement sleep density, more sleep apneas and leg movements in sleep than non-smokers. There were no differences regarding parameters of spectral analysis of the sleep electroencephalogram as well as in the sleep efficiency measured by PSG. Nevertheless smokers rated their sleep efficiency lower on the Pittsburgh Sleep Quality Index compared with non-smoking individuals, but no differences were detected on the SF-A. Plasma cotinine level correlated negatively with slow wave sleep in the smoking group.ConclusionsSmokers showed a number of insomnia-like sleep impairments. The findings suggest that it is important for sleep researchers to control smoking status in their analyses. Further research should focus on the causes and consequences of impaired sleep during tobacco cessation, as sleep disturbances are a known risk factor for early relapse after initial tobacco abstinence. 相似文献
57.
Ryan J. Jacoby Rachel C. Leonard Bradley C. Riemann Jonathan S. Abramowitz 《Cognitive therapy and research》2016,40(2):179-187
Cognitive-behavioral models of obsessive–compulsive disorder (OCD) propose that erroneous beliefs about the importance and need to control thoughts lead individuals with OCD to overuse maladaptive thought control strategies such as worry and self-punishment. These strategies are thought to backfire, leading to obsessional symptoms. Whereas previous studies have examined predictors of the use of thought control strategies, none have investigated these strategies as mediators in the prediction of OCD symptom severity. An additional gap in the literature is the lack of attention to OCD symptom dimensions. The present study, therefore, extended existing work by examining thought control strategies as mediators of the relationship between obsessive beliefs and OCD symptom dimensions in a treatment-seeking sample of 102 adults with OCD. In line with our hypotheses, the use of punishment (but not worry) as a thought control tactic mediated the relationship between dysfunctional beliefs about the importance/control of thoughts and unacceptable obsessions. These findings are discussed in terms of the conceptualization and treatment of OCD. Future research should investigate the extent to which these various thought control strategies may be helpful versus harmful using idiographic measures of thought control and employing experimental designs. 相似文献
58.
Kathryn M King Tracey JF Colella Peter Faris David R Thompson 《Journal of clinical nursing》2009,18(11):1617-1624
Aims. To examine the utility and validate the use of the Cardiac Depression Scale in patients who had first‐time coronary artery bypass graft surgery. Background. The Beck Depression Inventory, though frequently used, may not be sufficiently sensitive for use in cardiac patients. The Cardiac Depression Scale has been shown to identify the range of depression in medical cardiac patients. Design. Survey. Methods. The Beck Depression Inventory and Cardiac Depression Scale were administered to 120 men at hospital discharge, as well as six, 12 and 36 weeks postoperatively. Cronbach’s α scores were calculated for the measures at each point. Changes in scores over time were analysed using repeated measures analysis of variance. Associations between the measures scores were calculated using Pearson product–moment correlations. Agreement between the measures’ dichotomised scores (depression/no depression) was examined using Cohen’s Kappa statistic. Results. Internal consistency was similar for the Beck Depression Inventory (0·793–0·904) and Cardiac Depression Scale (0·859–0·910). Depression scores decreased over time with the Beck Depression Inventory [F(2·50, 175·29) = 22·27, p < 0·001] and Cardiac Depression Scale [F(2·68, 190·37) = 13·18, p < 0·001]. The measures had similar power [Cohen’s f = 0·65 (Beck Depression Inventory) and 0·43 (Cardiac Depression Scale)] to reveal changes over time. The continuous scores were highly correlated at each point [0·737 (p < 0·001)–0·819 (p < 0·001)]. However, when dichotomised scores were compared, the chance corrected level of agreement was less impressive [0·198 (p = 0·014)–0·381 (p < 0·001)]. Conclusions. The Cardiac Depression Scale may have utility for use with surgical cardiac patients. However, continued examination of this measure of depression is warranted. Relevance to clinical practice. Given the prevalence of depression and its negative impact on coronary artery disease, it is important to identify even mild depression in cardiac patients. Using a measure of depression specifically for cardiac patients, rather than a generic measure, may best accomplish this goal. 相似文献
59.
Interleukin-10 is a growth factor for human myeloma cells by induction of an oncostatin M autocrine loop 总被引:5,自引:1,他引:5
Gu ZJ; Costes V; Lu ZY; Zhang XG; Pitard V; Moreau JF; Bataille R; Wijdenes J; Rossi JF; Klein B 《Blood》1996,88(10):3972-3986
We have a previously reported that interleukin-10 (IL-10) is a potent but IL-6-unrelated growth factor for freshly explanted myeloma cells (Lu et al, Blood 85:2521, 1995). We have also shown that exogenous IL- 10 supported the growth of XG-1 and XG-2 human myeloma cell lines (HMCL) through an IL-6-independent mechanism. (Lu et al, Blood 85:2521, 1995). Because the IL-10 receptor does not involve the gp 130 IL-6 transducer, we have attempted to elucidate the mechanisms of IL-10 action on myeloma cells. Our results indicate that the myeloma cell growth factor activity of IL-10 was abrogated by an antibody to the gp 130 IL-6 transducer, indicating that it was mediated through one of the gp 130-activating cytokines. We found that myeloma cells from XG-1 and XG-2 HMCL and from 5 of 6 patients' tumoral samples produced oncostatin M (OM) constitutively but failed to produce IL-6, IL-11 and leukemia- inhibitory factor (LIF). The autocrine OM was inactive in the absence of IL-10 due to lack of a functional OM receptor on myeloma cells. IL- 10, by inducing the receptor for LIF (LIFR), produced a functional autocrine OM loop in XG-1 and XG-2 cells and in primary myeloma cells from 2 patients. We also found that some myeloma cell lines (XG-4, XG- 6, and XG-7) an fresh myeloma cells from 3 of 6 patients produced an autocrine IL-10 and that these cells constitutively expressed LIFR. One HMCL (XG-7) produced IL-10, OM, and IL-6 an expressed LIFR. The XG-7 cells used OM and IL-6 as autocrine growth factors. We have previously shown that IL-10 could induce IL-11 receptor in myeloma cells and confer on them sensitivity to IL-11 (Lu et al, FEBS Lett 377:515, 1995). Taken together, these results show that IL-10 is a key cytokine for inducing the expression of LIFR and IL-11R and possibly another uncharacterized OM coreceptor on myeloma cells and that OM and IL-10 might be produced by myeloma cells. They also emphasize that all myeloma cell growth factors reported to data involve an activation of the gp130 IL-6 transducer. 相似文献
60.
Human cytomegalovirus increases constitutive production of interleukin- 6 and leukemia inhibitory factor by bone marrow stromal cells 总被引:7,自引:0,他引:7
Lagneaux L; Delforge A; Snoeck R; Bosmans E; Moreau JF; Taupin JL; De Clercq E; Stryckmans P; Bron D 《Blood》1996,87(1):59-66
Human cytomegalovirus (CMV) infection is often associated with myelosuppression and acute inflammatory reaction in immunocompromised patients. We have previously documented that CMV exposure of bone marrow (BM) stromal cells reduces the capacity of these cells to support hematopoiesis because of a decreased production of colony- stimulating factors. This study examines the potential role of CMV on constitutive and lipopolysaccharide (LPS)-stimulated production of cytokines involved in inflammatory reaction, interleukin-6 (IL-6) and leukemia inhibitory factor (LIF) by BM stromal cells. The release of IL- 6 was already detectable 2 hours post CMV-infection (2.5-fold increase in production) and the cumulative production of IL-6 after 5 days of infection was 23 +/- 1.2 ng/mL (ninefold increase in production). CMV was also able to induce a time-dependent production of LIF that was maximal 8 hours after CMV infection (2.5-fold increase in production). Concomitantly, there was no detectable release of granulocyte colony- stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) by CMV-infected stromal cells. The similar IL-6 and LIF production in the presence of polymyxin B ruled out the possibility that this increase could be caused by contamination of the viral stock by endotoxin. In addition, ultraviolet-inactivated virus behaved similarly to live virus and caused the release of IL-6 and LIF. However, heat-inactivated CMV was unable to induce IL-6 and LIF secretion by BM stromal cells. The production of IL-6 and LIF was also evaluated after stimulation by LPS. After 5 days of CMV exposure, the LPS-stimulated production of IL-6 and LIF was significantly lower than uninfected controls. This LPS-induced release of cytokine production was found to be dependent of viral replication. The experiments have shown that CMV is a potent inducer of IL-6 and LIF with differential effect on constitutive and LPS- stimulated cytokine production by stromal cells; we suggest that CMV induction of IL-6 and LIF during the first hours of infection could play a role in CMV-induced inflammatory reaction. Moreover, our results show that human CMV can disturb the balanced cytokine network involved in the regulation of hematopoiesis. 相似文献