全文获取类型
收费全文 | 3015篇 |
免费 | 134篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 59篇 |
儿科学 | 67篇 |
妇产科学 | 32篇 |
基础医学 | 605篇 |
口腔科学 | 158篇 |
临床医学 | 351篇 |
内科学 | 518篇 |
皮肤病学 | 119篇 |
神经病学 | 210篇 |
特种医学 | 119篇 |
外科学 | 347篇 |
综合类 | 29篇 |
预防医学 | 161篇 |
眼科学 | 62篇 |
药学 | 200篇 |
中国医学 | 4篇 |
肿瘤学 | 115篇 |
出版年
2022年 | 30篇 |
2021年 | 58篇 |
2020年 | 31篇 |
2019年 | 37篇 |
2018年 | 29篇 |
2017年 | 35篇 |
2016年 | 39篇 |
2015年 | 56篇 |
2014年 | 55篇 |
2013年 | 74篇 |
2012年 | 115篇 |
2011年 | 116篇 |
2010年 | 60篇 |
2009年 | 78篇 |
2008年 | 136篇 |
2007年 | 146篇 |
2006年 | 151篇 |
2005年 | 152篇 |
2004年 | 117篇 |
2003年 | 161篇 |
2002年 | 135篇 |
2001年 | 109篇 |
2000年 | 101篇 |
1999年 | 99篇 |
1998年 | 26篇 |
1997年 | 37篇 |
1996年 | 26篇 |
1995年 | 20篇 |
1993年 | 20篇 |
1992年 | 51篇 |
1991年 | 37篇 |
1990年 | 48篇 |
1989年 | 54篇 |
1988年 | 38篇 |
1987年 | 32篇 |
1986年 | 34篇 |
1985年 | 33篇 |
1984年 | 22篇 |
1979年 | 20篇 |
1976年 | 21篇 |
1974年 | 24篇 |
1973年 | 21篇 |
1972年 | 21篇 |
1970年 | 22篇 |
1885年 | 18篇 |
1880年 | 32篇 |
1879年 | 21篇 |
1877年 | 21篇 |
1876年 | 21篇 |
1875年 | 18篇 |
排序方式: 共有3156条查询结果,搜索用时 15 毫秒
51.
52.
D Wenzel J Preisler W Schilling M Mohorn E V?lckner R Leonhardt R Sch?fer H Hoppe 《Zeitschrift für die gesamte innere Medizin und ihre Grenzgebiete》1976,31(24):1039-1043
It is reported on the results of a comparative examination of 18 patients with two usual ergometric methods (team pathophysiology of respiration and research group diseases of heart and circulation of the GDR). Referred to the intake of oxygen as a measure for the stress of the cardiorespiratory system by means of the ergometric methods recommended by the research group diseases of heart and circulation significantly higher minute volumes of the heart rate were established. Principal differences in the evidence of the two methods did not appear. 相似文献
53.
54.
G Moser G V Vacariu-Granser C Schneider T A Abatzi P Pokieser G Stacher-Janotta G Gaupmann U Weber T Wenzel M Roden 《Gastroenterology》1991,101(6):1512-1521
Thirty consecutive patients with globus sensation who were referred to a psychosomatic clinic prospectively underwent otolaryngological, videokinematographic, and manometric examinations of pharynx and esophagus to evaluate whether morphological abnormalities or motility disorders underlay their symptom. When indicated by findings, 24-hour pH-metry, scintigraphy of bolus transport, and esophagogastroscopy were performed. Seven patients were shown to have achalasia, 10 had "hypochalasia" (lower esophageal sphincter relaxation less than 75% with esophageal contraction abnormalities but no complete distal aperistalsis), and 1 had diffuse esophageal spasms; 2 patients had also hyperplastic lingual tonsils, 1 had tonsillitis, and 1 had a cervical spondylophyte. Nutcracker esophagus and nonspecific contraction abnormalities were found in 7 patients, and gastroesophageal reflux with esophagitis and a low lower esophageal sphincter resting pressure was found in 1; only 3 patients had normal esophageal motility. None had volunteered dysphagic symptoms at primary evaluation. Psychometric investigations in consenting patients showed no higher mean scores for state and trait anxiety, depression, hysteria, and hypochondriasis than in general medical outpatients. Esophageal motor disorders may, before giving rise to dysphagia, be sensed more vaguely and induce the globus sensation. However, only disappearance of the sensation after treatment allows inferring an etiological significance of such a disorder. 相似文献
55.
56.
Simon D. Brandt Pierce V. Kavanagh Folker Westphal Alexander Stratford Simon P. Elliott Geraldine Dowling Adam L. Halberstadt 《Drug testing and analysis》2020,12(10):1514-1521
Recent investigations have shown that N‐ethyl‐N‐cyclopropyl lysergamide (ECPLA) produces LSD‐like behavioral effects in mice, which suggests that it may act as a hallucinogen in humans. Although the use of ECPLA as a recreational drug has been limited, key analytical data that can be used to detect ECPLA are required for future forensic and clinical investigations. ECPLA is an isomer of (2′S,4′S)‐lysergic acid 2,4‐dimethylazetidide (LSZ), a lysergamide that emerged as a recreational drug in 2013. Several analytical approaches were examined, including single‐ and tandem mass spectrometry platforms at low and high resolution, gas‐ and liquid chromatography (GC, LC), nuclear magnetic resonance spectroscopy (NMR), and GC condensed‐phase infrared spectroscopy (GC‐sIR). ECPLA and LSZ could be differentiated by NMR, GC‐sIR, GC, and LC‐based methods. The electron ionization mass spectra of ECPLA and LSZ contained ion clusters typically observed with related lysergamides such as m/z 150–155, m/z 177–182, m/z 191–197, m/z 205–208, and m/z 219–224. One of the significant differences in abundance related to these clusters included ions at m/z 196 and m/z 207/208. The base peaks were detected at m/z 221 in both cases followed by the retro‐Diels‐Alder fragment at m/z 292. Minor but noticeable differences between the two isomers could also be seen in the relative abundance of m/z 98 and m/z 41. Electrospray ionization mass spectra included lysergamide‐related ions at m/z 281, 251, 223, 208, 197, 180, and 140. LSZ (but not ECPLA) showed product ions at m/z 267 and m/z 98 under the conditions used. 相似文献
57.
Simon D. Brandt Pierce V. Kavanagh Folker Westphal Alexander Stratford Anna U. Odland Adam K. Klein Geraldine Dowling Nicola M. Dempster Jason Wallach Torsten Passie Adam L. Halberstadt 《Drug testing and analysis》2020,12(6):812-826
Lysergic acid diethylamide (LSD) is a prototypical serotonergic psychedelic drug and the subject of many clinical investigations. In recent years, a range of lysergamides has emerged with the production of some being inspired by the existing scientific literature. Others, for example various 1‐acyl substituted lysergamides, did not exist before their appearance as research chemicals. 1‐Cylopropanoyl‐LSD (1CP‐LSD) has recently emerged as a new addition to the group of lysergamide‐based designer drugs and is believed to be psychoactive in humans. In this investigation, 1CP‐LSD was subjected to detailed analytical characterizations including various mass spectrometry (MS) platforms, gas and liquid chromatography, nuclear magnetic resonance spectroscopy, solid phase and GC condensed phase infrared spectroscopy. Analysis by GC–MS also revealed the detection of artificially induced degradation products. Incubation of 1CP‐LSD with human serum led to the formation of LSD, indicating that it may act as a prodrug for LSD in vivo, similar to other 1‐acyl substituted lysergamides. The analysis of blotters and pellets is also included. 1CP‐LSD also induces the head‐twitch response (HTR) in C57BL/6 J mice, indicating that it produces an LSD‐like behavioural profile. 1CP‐LSD induced the HTR with an ED50 = 430.0 nmol/kg which was comparable to 1P‐LSD (ED50 = 349.6 nmol/kg) investigated previously. Clinical studies are required to determine the potency and profile of the effects produced by 1CP‐LSD in humans. 相似文献
58.
In this article, we describe a case of left ventricular assist device endocarditis caused by a vancomycin-intermediate Staphylococcus aureus strain that was successfully treated with ceftaroline. Left ventricular assist device infections are briefly reviewed, and the current knowledge regarding vancomycin resistance is discussed. 相似文献
59.
Objective assessment of the combined effect of exomass-related- and motion artefacts in cone beam CT
Matheus Lima Oliveira Amanda P Candemil Deborah Q Freitas Francisco Haiter-Neto Ann Wenzel Rubens Spin-Neto 《Dento maxillo facial radiology》2021,50(1)
Objectives:To assess quantitatively the combined effect of exomass-related- and motion artefacts on voxel value parameters in cone beam CT (CBCT).Methods:A cylindrical phantom was manufactured, containing 21 tubes filled with a radiopaque solution, allowing the inclusion of three titanium implants in the periphery to induce exomass-related artefacts. The phantom was mounted on a robot simulating 0.75-, 1.5-, and 3 mm movements (nodding/lateral rotation/tremor). CBCT images with/without exomass and with/without movements were acquired in duplicate in three units: Cranex 3Dx, Orthophos SL-3D, and X1 (with motion-artefact correction). A cylindrical volume of interest was defined in each tube and voxel value mean and standard deviation were assessed. For each CBCT volume, the 21 mean voxel values were averaged providing the overall mean voxel value (MVV), and the standard deviation (among the 21 values) was calculated providing overall voxel value inhomogeneity (VVI). The standard deviation from each of the 21 volumes-of-interest were averaged, providing overall image noise (IN). The effect of the diverse tested situations was inferred from a repeated-measures analysis of variance, followed by Sidak’s test (α = 0.05).Results:Overall, images acquired with exomass showed significantly (p ≤ 0.05) lower MVV, and higher VVI and IN. Motion artefacts aggravated exomass-related alterations. MVV and VVI were mostly affected by 3 mm nodding movements. Motion-artefact correction eliminated the deleterious effect of movement.Conclusions:CBCT voxel-value parameters are altered by exomass-related artefacts, and this finding is aggravated in the presence of motion artefacts. Motion-artefact correction effectively eliminated the deleterious impact of movement. 相似文献
60.
Wenzel Jan-Per Petersen Elina Nikorowitsch Julius Müller Jessica Kölbel Tilo Reichenspurner Hermann Blankenberg Stefan Girdauskas Evaldas 《The international journal of cardiovascular imaging》2021,37(12):3439-3449
The International Journal of Cardiovascular Imaging - To evaluate the prevalence of aortic regurgitation (AR) and associations between the individual aortic root components and AR severity in the... 相似文献