全文获取类型
收费全文 | 1042篇 |
免费 | 62篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 10篇 |
妇产科学 | 12篇 |
基础医学 | 164篇 |
口腔科学 | 14篇 |
临床医学 | 107篇 |
内科学 | 246篇 |
皮肤病学 | 10篇 |
神经病学 | 126篇 |
特种医学 | 34篇 |
外科学 | 139篇 |
综合类 | 6篇 |
预防医学 | 44篇 |
眼科学 | 10篇 |
药学 | 83篇 |
中国医学 | 2篇 |
肿瘤学 | 96篇 |
出版年
2024年 | 3篇 |
2023年 | 7篇 |
2022年 | 47篇 |
2021年 | 52篇 |
2020年 | 22篇 |
2019年 | 30篇 |
2018年 | 41篇 |
2017年 | 18篇 |
2016年 | 23篇 |
2015年 | 28篇 |
2014年 | 32篇 |
2013年 | 45篇 |
2012年 | 91篇 |
2011年 | 93篇 |
2010年 | 44篇 |
2009年 | 37篇 |
2008年 | 78篇 |
2007年 | 61篇 |
2006年 | 54篇 |
2005年 | 77篇 |
2004年 | 58篇 |
2003年 | 56篇 |
2002年 | 47篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 15篇 |
1996年 | 3篇 |
1995年 | 9篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有1107条查询结果,搜索用时 15 毫秒
21.
Janetta V. Korneva Svetlana A. Kornienko Vadim V. Kuklin Nikolay M. Pronin Malcolm K. Jones 《Parasitology research》2014,113(1):425-432
Uterine organization and interaction with developing eggs in Tetrabothrius erostris (Tetrabothriidea), Nippotaenia mogurndae (Nippotaeniidea), Arostrilepis tenuicirrosa, and Monocercus arionis (Cyclophyllidea), cestodes belonging to three different orders, were investigated by scanning electron microscopy. The interactions were traced from sexually mature to gravid proglottids for all species. Pieces of evidence of interactions among these species include specific tight contacts between microlamellae of the uterine epithelium and the egg capsule, networks of fibrils between eggs and uterus, or numerous branched diverticula of the uterine wall that surround eggs or combinations of these. The contacts between uterine epithelium and eggs take place in mature and post-mature proglottids, at a period of development when eggs are newly formed and the embryos are rapidly developing. The eggs grow and develop actively in tight contact with the uterine wall. The maximum diameter of eggs increases 1.5–2 times (or 3.5–4 times in M. arionis) during development. In all species, the intimate contacts between uterus and eggs have weakened or disappeared by the time the proglottids have become gravid. The association between uterus and eggs thus appears as strong evidence of active trophic interaction (or matrotrophy) between the parent organism and developing eggs. 相似文献
22.
Alexander V Tyakht Dmitry G Alexeev Anna S Popenko Elena S Kostryukova Vadim M Govorun 《Gut microbes》2014,5(3):351-356
A multitude of metagenomic studies has brought to light an enormous richness of human gut microbiota compositions. In this space of possible configurations, clinical specialists are trying to mine the markers of healthy microbiota via case-control and longitudinal studies. We have discovered potentially beneficial communities while examining the microbial diversity in rural Russians in comparison with the urban dwellers. In this addendum, we further examine the data by elaborating on some of the less common types and suggesting the possible co-metabolism of their drivers. In the light of the first validated clinically effective bacterial transplantation, we discuss the concept of a reference healthy microbiota, outline the problems encountered on the way to its restoration in the developed world, and speculate if rural communities can serve as a source for its prototype. 相似文献
23.
John W. Warren Vadim Morozov Fred M. Howard Ursula Wesselmann Lisa Gallicchio Patricia Langenberg Daniel J. Clauw 《Journal of psychosomatic research》2014
Objective
Certain functional somatic syndromes (FSSs) such as fibromyalgia and irritable bowel syndrome are accompanied by diffuse pain amplification. Women with interstitial cystitis/bladder pain syndrome (IC/BPS) have numerous FSSs, as well as other non-bladder syndromes (NBSs) that are linked to the FSSs. They also report multiple surgeries. Since pain is a common indication for surgery, we tested the hypothesis that NBSs were associated with surgeries.Methods
We interviewed 312 incident IC/BPS cases and controls on NBSs and number of surgeries before the index date (for cases, IC/BPS onset date). Poisson and logistic regression analyses adjusted for age, race, educational level, and menopause.Results
Number of surgeries increased with number of NBSs in both cases and controls whether chronic pelvic pain (CPP), the only NBS generally accepted as an indication for surgery, was present or not. Logistic regression analysis showed that among cases CPP was the only individual NBS associated with a history of multiple surgeries, and then only modestly [odds ratio (OR) 1.9, confidence intervals (CI) 1.06, 3.2]. By far the strongest association was the number of NBSs. The OR for multiple surgeries increased with number of NBSs: for cases with 4–5 NBSs the OR was 14.1 (1.8, 113) and with 6–9 NBSs, 33.1 (3.9, 279). Controls had fewer syndromes and fewer surgeries and this linkage was less prominent.Conclusion
Among IC/BPS cases, the number of NBSs was strongly correlated with the number of surgeries. Understanding temporal relationships will be necessary to explore causal linkages and may modify surgical practice. 相似文献24.
Parker DS Zhang F Kim YS Kaiser RI Landera A Kislov VV Mebel AM Tielens AG 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(1):53-58
Polycyclic aromatic hydrocarbons (PAHs) are regarded as key molecules in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest prototype—naphthalene (C10H8)—has remained an open question. Here, we show in a combined crossed beam and theoretical study that naphthalene can be formed in the gas phase via a barrierless and exoergic reaction between the phenyl radical (C6H5) and vinylacetylene (CH2 = CH-C ≡ CH) involving a van-der-Waals complex and submerged barrier in the entrance channel. Our finding challenges conventional wisdom that PAH-formation only occurs at high temperatures such as in combustion systems and implies that low temperature chemistry can initiate the synthesis of the very first PAH in the interstellar medium. In cold molecular clouds, barrierless phenyl-type radical reactions could propagate the vinylacetylene-mediated formation of PAHs leading to more complex structures like phenanthrene and anthracene at temperatures down to 10 K. 相似文献
25.
26.
Chandraratna PA Kuznetsov VA Mohar DS Sidarous PF Scheutz J Krinochkin DV Pak YA Mohar P Arawgoda U 《Echocardiography (Mount Kisco, N.Y.)》2012,29(6):695-699
Background: Dobutamine stress echocardiography (DSE) is commonly used for the diagnosis for coronary artery disease (CAD). We previously demonstrated that squatting induces wall motion abnormalities (WMA) in areas subtended by stenotic coronary arteries. Objective: This study was designed to test the hypothesis that dobutamine and squatting stress echocardiography are equally useful for the diagnosis of CAD. Methods: We studied 39 patients who were scheduled to have coronary angiography for the evaluation of chest pain. Each patient had squatting stress echocardiography followed by DSE. For squatting stress echocardiography the echocardiogram in standard views was recorded in the standing position. The procedure was repeated during squatting for 2 minutes. Dobutamine echocardiography was performed using standard protocol. The squatting and dobutamine stress echocardiograms were interpreted by an observer blinded to the results of coronary angiography. Results: During squatting, new or worsening WMA developed in 20 patients. Six patients developed WMA in the left anterior descending artery territory, three in circumflex territory, three in the right coronary artery territory, and eight in multiple coronary territories. The sensitivity, specificity, and accuracy of squatting echocardiography for diagnosis of CAD were 95%, 94%, and 94%, respectively. For DSE, the sensitivity, specificity, and accuracy for the diagnosis of CAD were 85%, 94%, and 90%, respectively. There was no significant difference between squatting and dobutamine stress echocardiography for the diagnosis of CAD (P = 0.702). Conclusion: These data indicate that squatting and dobutamine echocardiography are equally useful in the diagnosis of CAD. In selected patients, squatting echocardiography may be used in place of dobutamine echocardiography for the diagnosis of CAD. (Echocardiography 2012;29:695–699) 相似文献
27.
Alexey A. Moskalev Mikhail V. Shaposhnikov Ekaterina N. Plyusnina Alex Zhavoronkov Arie Budovsky Hagai Yanai Vadim E. Fraifeld 《Ageing research reviews》2013,12(2):661-684
Since the first publication on Somatic Mutation Theory of Aging (Szilárd, 1959), a great volume of knowledge in the field has been accumulated. Here we attempted to organize the evidence “for” and “against” the hypothesized causal role of DNA damage and mutation accumulation in aging in light of four Koch-like criteria. They are based on the assumption that some quantitative relationship between the levels of DNA damage/mutations and aging rate should exist, so that (i) the longer-lived individuals or species would have a lower rate of damage than the shorter-lived, and (ii) the interventions that modulate the level of DNA damage and repair capacity should also modulate the rate of aging and longevity and vice versa. The analysis of how the existing data meets the proposed criteria showed that many gaps should still be filled in order to reach a clear-cut conclusion. As a perspective, it seems that the main emphasis in future studies should be put on the role of DNA damage in stem cell aging. 相似文献
28.
Thomas A. Singleton Hussein Bdair Justin J. Bailey Sangho Choi Arturo Aliaga Pedro Rosa-Neto Ralf Schirrmacher Vadim Bernard-Gauthier Alexey Kostikov 《Journal of labelled compounds & radiopharmaceuticals》2020,63(3):144-150
Herein we report an efficient radiolabeling of a 18F-fluorinated derivative of dual inhibitor GW2580, with its subsequent evaluation as a positron emission tomography (PET) tracer candidate for imaging of two neuroreceptor targets implicated in the pathophysiology of neurodegeneration: tropomyosin receptor kinases (TrkB/C) and colony stimulating factor receptor (CSF-1R). [18F]FOMPyD was synthesized from a boronic acid pinacolate precursor via copper-mediated 18F-fluorination concerted with thermal deprotection of the four Boc groups on a diaminopyrimidine moiety in an 8.7±2.8% radiochemical yield, a radiochemical purity >99%, and an effective molar activity of 187±93 GBq/μmol. [18F]FOMPyD showed moderate brain permeability in wild-type rats (SUVmax = 0.75) and a slow washout rate. The brain uptake was partially reduced (ΔAUC40–90 = 11.6%) by administration of the nonradioactive FOMPyD (up to 30 μg/kg). In autoradiography, [18F]FOMPyD exhibits ubiquitous distribution in rat and human brain tissues with relatively high nonspecific binding revealed by self-blocking experiment. The binding was blocked by TrkB/C inhibitors, but not with a CSF-1R inhibitor, suggesting selective binding to the former receptor. Although an unfavorable pharmacokinetic profile will likely preclude application of [18F]FOMPyD as a PET tracer for brain imaging, the concomitant one-pot copper-mediated 18F-fluorination/Boc-deprotection is a practical technique for the automated radiosynthesis of acid-sensitive PET tracers. 相似文献
29.
Scanvion Quentin Le Garff Erwan Gosset Didier Hédouin Valéry Mesli Vadim 《Forensic science, medicine, and pathology》2019,15(4):612-615
Forensic Science, Medicine and Pathology - The Morel-Lavallée lesion is an infrequent traumatic lesion that the forensic physician may need to evaluate during examination of a victim. Using a... 相似文献
30.
Svetlana Bozhkova Rashid Tikhilov Dmitry Labutin Alexey Denisov Igor Shubnyakov Vadim Razorenov Vasilii Artyukh Anna Rukina 《Journal of orthopaedics and traumatology》2016,17(4):369-376