全文获取类型
收费全文 | 6580篇 |
免费 | 477篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 59篇 |
儿科学 | 208篇 |
妇产科学 | 143篇 |
基础医学 | 978篇 |
口腔科学 | 97篇 |
临床医学 | 707篇 |
内科学 | 1260篇 |
皮肤病学 | 164篇 |
神经病学 | 703篇 |
特种医学 | 163篇 |
外科学 | 639篇 |
综合类 | 52篇 |
一般理论 | 11篇 |
预防医学 | 685篇 |
眼科学 | 114篇 |
药学 | 416篇 |
中国医学 | 9篇 |
肿瘤学 | 668篇 |
出版年
2024年 | 10篇 |
2023年 | 99篇 |
2022年 | 176篇 |
2021年 | 302篇 |
2020年 | 209篇 |
2019年 | 269篇 |
2018年 | 263篇 |
2017年 | 222篇 |
2016年 | 240篇 |
2015年 | 231篇 |
2014年 | 310篇 |
2013年 | 390篇 |
2012年 | 591篇 |
2011年 | 548篇 |
2010年 | 273篇 |
2009年 | 279篇 |
2008年 | 419篇 |
2007年 | 406篇 |
2006年 | 362篇 |
2005年 | 337篇 |
2004年 | 283篇 |
2003年 | 246篇 |
2002年 | 229篇 |
2001年 | 31篇 |
2000年 | 22篇 |
1999年 | 19篇 |
1998年 | 33篇 |
1997年 | 19篇 |
1996年 | 19篇 |
1995年 | 15篇 |
1994年 | 19篇 |
1993年 | 20篇 |
1992年 | 11篇 |
1991年 | 11篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 14篇 |
1987年 | 7篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1969年 | 6篇 |
1958年 | 3篇 |
1954年 | 3篇 |
1926年 | 3篇 |
排序方式: 共有7076条查询结果,搜索用时 0 毫秒
61.
van den Wijngaard JP Lewi L Lopriore E Robyr R Middeldorp JM Vandenbussche FP Devlieger R Deprest J Ville Y van Gemert MJ 《Placenta》2007,28(7):611-615
Our objective was to explain the clinical presentations of sustained arteriovenous anastomotic transfusion of blood after incomplete laser therapy in twin-to-twin transfusion syndrome (TTTS). We extended our mathematical model of TTTS by adding the dynamics of hematocrit, and simulated incomplete laser therapy, first, by leaving one patent opposite arteriovenous anastomosis from the recipient to the donor and, second, by leaving one patent arteriovenous anastomosis from the donor to the recipient. In both simulations we reproduced the clinical observation of severe hematocrit discordance preceding delayed amniotic fluid imbalance. In conclusion, incomplete laser therapy may cause a severe circulatory imbalance between the twins which presents predominantly as discordant hematocrits rather than discordant amniotic fluid volumes as in primary TTTS. These results imply that the anemia-polycythemia sequence is a sensitive mechanism to identify transfusion reversal after complicated laser therapy, confirming the suggested role of middle cerebral artery peak systolic velocity Doppler measurements as a useful method of follow-up. 相似文献
62.
Felipe Penagos-Tabares Ratchaneewan Khiaosa-ard Marlene Schmidt Eva-Maria Bartl Johanna Kehrer Veronika Nagl Johannes Faas Michael Sulyok Rudolf Krska Qendrim Zebeli 《Toxins》2022,14(7)
Dairy production is a pivotal economic sector of Austrian and European agriculture. Dietary toxins and endocrine disruptors of natural origin such as mycotoxins and phytoestrogens can affect animal health, reproduction, and productivity. This study characterized the profile of a wide spectrum of fungal, plant, and unspecific secondary metabolites, including regulated, emerging, and modified mycotoxins, phytoestrogens, and cyanogenic glucosides, in complete diets of lactating cows from 100 Austrian dairy farms. To achieve this, a validated multi-metabolite liquid chromatography/electrospray ionization–tandem mass spectrometric (LC/ESI–MS/MS) method was employed, detecting 155 of >800 tested metabolites. Additionally, the most influential dietary and geo-climatic factors related to the dietary mycotoxin contamination of Austrian dairy cattle were recognized. We evidenced that the diets of Austrian dairy cows presented ubiquitous contamination with mixtures of mycotoxins and phytoestrogens. Metabolites derived from Fusarium spp. presented the highest concentrations, were the most recurrent, and had the highest diversity among the detected fungal compounds. Zearalenone, deoxynivalenol, and fumonisin B1 were the most frequently occurring mycotoxins considered in the EU legislation, with detection frequencies >70%. Among the investigated dietary factors, inclusion of maize silage (MS) and straw in the diets was the most influential factor in contamination with Fusarium-derived and other fungal toxins and metabolites, and temperature was the most influential among the geo-climatic factors. 相似文献
63.
Robin A. Schoonderwoerd Mischa de Rover Jan A. M. Janse Lydiane Hirschler Channa R. Willemse Leonie Scholten Ilse Klop Sander van Berloo Matthias J. P. van Osch Dick F. Swaab Johanna H. Meijer 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(13)
In modern society, the widespread use of artificial light at night disrupts the suprachiasmatic nucleus (SCN), which serves as our central circadian clock. Existing models describe excitatory responses of the SCN to primarily blue light, but direct measures in humans are absent. The combination of state-of-the-art neuroimaging techniques and custom-made MRI compatible light-emitting diode devices allowed to directly measure the light response of the SCN. In contrast to the general expectation, we found that blood oxygen level–dependent (BOLD) functional MRI signals in the SCN were suppressed by light. The suppressions were observed not only in response to narrowband blue light (λmax: 470 nm) but remarkably, also in response to green (λmax: 515 nm) and orange (λmax: 590 nm), but not to violet light (λmax: 405 nm). The broadband sensitivity of the SCN implies that strategies on light exposure should be revised: enhancement of light levels during daytime is possible with wavelengths other than blue, while during nighttime, all colors are potentially disruptive.Due to the Earth’s rotation around its axis, many organisms developed an internal clock to anticipate the predictable changes in the environment that occur every 24 h, including the daily light–dark cycle. In mammals, this clock is located in the suprachiasmatic nucleus (SCN), located in the hypothalamus directly above the optic chiasm (1, 2). The SCN receives information from the retina regarding ambient light levels via intrinsically photosensitive retinal ganglion cells (ipRGCs), thus synchronizing its internal clock to the external light–dark cycle. ipRGCs contain the photopigment melanopsin, which is maximally sensitive to blue light, with a peak response to 480-nm light (3, 4). In addition, ipRGCs also receive input from rod cells and cone cells (5–7). The three cone cell subtypes in the human retina respond maximally to 420-nm, 534-nm, and 563-nm light, while rod cells respond maximally to 498-nm light (8). In rodents, input from cone cells renders the SCN sensitive to a broad spectrum of wavelengths (9), while rod cells mediate the SCN’s sensitivity to low-intensity light (10, 11). Recently, these findings in rodents were proposed to translate to humans (12), suggesting that the human clock is not only sensitive to blue light, but may also be sensitive to other colors.In humans, circadian responses to light are generally measured indirectly (e.g., by measuring melatonin levels or 24-h behavioral rhythms). These indirect measures revealed that circadian responses to light in humans are most sensitive to blue light (13–16); however, green light has also been found to contribute to circadian phase shifting and changes in melatonin to a larger extent than would have been predicted based solely on the melanopsin response, suggesting that rods and/or cones may also provide functional input to the circadian system in humans (17). Despite this indirect evidence suggesting that several colors can affect the human circadian clock, this has never been measured directly due to technical limitations. Thus, current guidelines regarding the use of artificial light are based solely on the clock’s sensitivity to blue light. For example, blue light is usually filtered out in electronic screens during the night (18, 19), and blue-enriched light is used by night shift workers to optimize their body rhythm for achieving maximum performance (20–22).The ability to directly image the human SCN in vivo has been severely limited due to its small size and the relatively low spatial resolution provided by medical imaging devices. Previous functional MRI (fMRI) studies using 3-Tesla (3T) scanners were restricted to recording the “suprachiasmatic area,” which encompasses a large part of the hypothalamus and thus includes many other potentially light-sensitive nuclei (23–25). To overcome this limitation, we used a 7T MRI scanner, which can provide images with sufficiently high spatial resolution to image small brain nuclei (26) such as the SCN. Here, we applied colored light stimuli to healthy volunteers using a custom-designed MRI-compatible light-emitting diode (LED) device designed to stimulate specific photoreceptors while measuring SCN activity using fMRI. Using analytical approaches, we then identified the SCN’s response, the smallest brain nucleus that has so far been imaged. We found that the human SCN responds to a broad range of wavelengths (i.e., blue, green and orange light). Surprisingly, we also found that the blood oxygen level–dependent (BOLD) fMRI signal at the SCN is actually suppressed—not activated—by light. 相似文献
64.
Sevgi Bektas Johanna Louise Keeler Lisa M. Anderson Hiba Mutwalli Hubertus Himmerich Janet Treasure 《Nutrients》2022,14(9)
Disgust and self-disgust are aversive emotions which are often encountered in people with eating disorders. We conducted a systematic review and meta-analysis of disgust and self-disgust in people with eating disorders using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The systematic review of the literature revealed 52 original research papers. There was substantial heterogeneity regarding the research question and outcomes. However, we found 5 articles on disgust elicited by food images, 10 studies on generic disgust sensitivity, and 4 studies on self-disgust, and we proceeded to a meta-analytic approach on these studies. We found that women with eating disorders have significantly higher momentary disgust feelings in response to food images (1.32; 95% CI 1.05, 1.59), higher generic disgust sensitivity (0.49; 95% CI 0.24, 0.71), and higher self-disgust (1.90; 95% CI 1.51, 2.29) compared with healthy controls. These findings indicate the potential clinical relevance of disgust and self-disgust in the treatment of eating disorders. 相似文献
65.
Short‐term intervention to reduce anxiety before coronary artery bypass surgery – a randomised controlled trial 下载免费PDF全文
66.
Shalaila S. Haas Linda A. Antonucci Julian Wenzel Anne Ruef Bruno Biagianti Marco Paolini Boris-Stephan Rauchmann Johanna Weiske Joseph Kambeitz Stefan Borgwardt Paolo Brambilla Eva Meisenzahl Raimo K. R. Salokangas Rachel Upthegrove Stephen J. Wood Nikolaos Koutsouleris Lana Kambeitz-Ilankovic 《Neuropsychopharmacology》2021,46(4):828
Two decades of studies suggest that computerized cognitive training (CCT) has an effect on cognitive improvement and the restoration of brain activity. Nevertheless, individual response to CCT remains heterogenous, and the predictive potential of neuroimaging in gauging response to CCT remains unknown. We employed multivariate pattern analysis (MVPA) on whole-brain resting-state functional connectivity (rsFC) to (neuro)monitor clinical outcome defined as psychosis-likeness change after 10-hours of CCT in recent onset psychosis (ROP) patients. Additionally, we investigated if sensory processing (SP) change during CCT is associated with individual psychosis-likeness change and cognitive gains after CCT. 26 ROP patients were divided into maintainers and improvers based on their SP change during CCT. A support vector machine (SVM) classifier separating 56 healthy controls (HC) from 35 ROP patients using rsFC (balanced accuracy of 65.5%, P < 0.01) was built in an independent sample to create a naturalistic model representing the HC-ROP hyperplane. This model was out-of-sample cross-validated in the ROP patients from the CCT trial to assess associations between rsFC pattern change, cognitive gains and SP during CCT. Patients with intact SP threshold at baseline showed improved attention despite psychosis status on the SVM hyperplane at follow-up (p < 0.05). Contrarily, the attentional gains occurred in the ROP patients who showed impaired SP at baseline only if rsfMRI diagnosis status shifted to the healthy-like side of the SVM continuum. Our results reveal the utility of MVPA for elucidating treatment response neuromarkers based on rsFC-SP change and pave the road to more personalized interventions.Subject terms: Predictive markers, Psychosis 相似文献
67.
Elizabeth S. Maywood Lesley Drynan Johanna E. Chesham Mathew D. Edwards Hugues Dardente Jean-Michel Fustin David G. Hazlerigg John S. O’Neill Gemma F. Codner Nicola J. Smyllie Marco Brancaccio Michael H. Hastings 《Proceedings of the National Academy of Sciences of the United States of America》2013,110(23):9547-9552
The suprachiasmatic nucleus (SCN) coordinates circadian rhythms that adapt the individual to solar time. SCN pacemaking revolves around feedback loops in which expression of Period (Per) and Cryptochrome (Cry) genes is periodically suppressed by their protein products. Specifically, PER/CRY complexes act at E-box sequences in Per and Cry to inhibit their transactivation by CLOCK/BMAL1 heterodimers. To function effectively, these closed intracellular loops need to be synchronized between SCN cells and to the light/dark cycle. For Per expression, this is mediated by neuropeptidergic and glutamatergic extracellular cues acting via cAMP/calcium-responsive elements (CREs) in Per genes. Cry genes, however, carry no CREs, and how CRY-dependent SCN pacemaking is synchronized remains unclear. Furthermore, whereas reporter lines are available to explore Per circadian expression in real time, no Cry equivalent exists. We therefore created a mouse, B6.Cg-Tg(Cry1-luc)01Ld, carrying a transgene (mCry1-luc) consisting of mCry1 elements containing an E-box and E′-box driving firefly luciferase. mCry1-luc organotypic SCN slices exhibited stable circadian bioluminescence rhythms with appropriate phase, period, profile, and spatial organization. In SCN lacking vasoactive intestinal peptide or its receptor, mCry1 expression was damped and desynchronized between cells. Despite the absence of CREs, mCry1-luc expression was nevertheless (indirectly) sensitive to manipulation of cAMP-dependent signaling. In mPer1/2-null SCN, mCry1-luc bioluminescence was arrhythmic and no longer suppressed by elevation of cAMP. Finally, an SCN graft procedure showed that PER-independent as well as PER-dependent mechanisms could sustain circadian expression of mCry1. The mCry1-luc mouse therefore reports circadian mCry1 expression and its interactions with vasoactive intestinal peptide, cAMP, and PER at the heart of the SCN pacemaker. 相似文献
68.
Venom delivery systems (VDS) are common in the animal kingdom, but rare amongst mammals. New definitions of venom allow us to reconsider its diversity amongst mammals by reviewing the VDS of Chiroptera, Eulipotyphla, Monotremata, and Primates. All orders use modified anterior dentition as the venom delivery apparatus, except Monotremata, which possesses a crural system. The venom gland in most taxa is a modified submaxillary salivary gland. In Primates, the saliva is activated when combined with brachial gland exudate. In Monotremata, the crural spur contains the venom duct. Venom functions include feeding, intraspecific competition, anti-predator defense and parasite defense. Including mammals in discussion of venom evolution could prove vital in our understanding protein functioning in mammals and provide a new avenue for biomedical and therapeutic applications and drug discovery. 相似文献
69.
70.
PEGylation is a modification commonly used to increase the half-life of therapeutic proteins. The strategy for immunogenicity testing of these compounds should include methods to detect both anti-protein and anti-PEG antibodies. We previously reported a method for the detection of anti-PEG antibodies using ProterixBio’s (formerly BioScale) acoustic membrane microparticle (AMMP) technology. Our initial method development work showed the assay was capable of detecting antibodies in human serum with a sensitivity of 1 μg/mL with good reproducibility (CV?<?7%). Since the publication of this initial paper, additional experimentation was performed in an effort to validate the assay for support of clinical sample analysis. This additional data indicate that the method has high variability (CV%?>?20) and is unsuitable to support clinical sample analysis. 相似文献