全文获取类型
收费全文 | 725篇 |
免费 | 79篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 68篇 |
妇产科学 | 6篇 |
基础医学 | 97篇 |
口腔科学 | 30篇 |
临床医学 | 75篇 |
内科学 | 166篇 |
皮肤病学 | 19篇 |
神经病学 | 24篇 |
特种医学 | 129篇 |
外科学 | 57篇 |
综合类 | 42篇 |
预防医学 | 24篇 |
眼科学 | 29篇 |
药学 | 15篇 |
肿瘤学 | 30篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 19篇 |
2017年 | 7篇 |
2016年 | 21篇 |
2015年 | 23篇 |
2014年 | 28篇 |
2013年 | 42篇 |
2012年 | 22篇 |
2011年 | 18篇 |
2010年 | 46篇 |
2009年 | 45篇 |
2008年 | 18篇 |
2007年 | 32篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 14篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 40篇 |
1997年 | 42篇 |
1996年 | 42篇 |
1995年 | 36篇 |
1994年 | 23篇 |
1993年 | 28篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 18篇 |
1988年 | 15篇 |
1987年 | 10篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 12篇 |
1982年 | 5篇 |
1981年 | 13篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 2篇 |
1884年 | 1篇 |
排序方式: 共有814条查询结果,搜索用时 0 毫秒
71.
Can we identify termination of resuscitation criteria in cardiac arrest due to drowning: results from the French national out‐of‐hospital cardiac arrest registry 下载免费PDF全文
Hervé Hubert PhD Joséphine Escutnaire MSc Pierre Michelet MD PhD Evgéniya Babykina PhD Carlos El Khoury MD PhD Karim Tazarourte MD PhD Christian Vilhelm PhD Lahcen El Hiki PhD Benjamin Guinhouya PhD Pierre‐Yves Gueugniaud MD PhD on behalf GR‐RéAC 《Journal of evaluation in clinical practice》2016,22(6):928-935
72.
73.
74.
Jens Vogel-Claussen Jan Skrok Elliot K Fishman João AC Lima Ashish S Shah David A Bluemke 《Journal of cardiothoracic surgery》2009,4(1):42-5
We report the case of a 67 year-old patient who presented with worsening chest pain and shortness of breath, four days post
acute myocardial infarction. Contrast enhanced computed tomography of the chest ruled out a pulmonary embolus but revealed
an unexpected small subepicardial aneurysm (SEA) in the lateral left ventricular wall which was confirmed on cardiac magnetic
resonance imaging. Intraoperative palpation of the left lateral wall was guided by the cardiac MRI and CT findings and confirmed
the presence of focally thinned and weakened myocardium, covered by epicardial fat. An aneurysmorrhaphy was subsequently performed
in addition to coronary bypass surgery and a mitral valve repair. The patient was discharged home on post operative day eight
in good condition and is feeling well 2 years after surgery. 相似文献
75.
AC Unger H Cabrera-Palacios AP Schulz Ch Jürgens A Paech 《European journal of medical research》2009,14(6):264-271
Introduction
At present there are no reliable non-traumatic and non-invasive methods to analyse the healing process and loosening status after total hip replacement. Therefore early as well as late loosening of prosthesis and interface component problems are difficult to be found or diagnosed at any time.Methods
In a cadaver study the potential application of Resonance Frequency Monitoring (RFM) will be evaluated as a non-invasive and non-traumatic method to monitor loosening and interface problems in hip replacement. In a 65 year old female cadaver different stability scenarios for a total hip replacement (shaft, head/modular head and cup, ESKA, Luebeck, Germany) are simulated in cemented and cement less prosthesis and then analysed with RFM. The types of stability vary from secure/press-fit to interface-shaft disruption.Results
The RFM shows in cemented as well as cement less prosthesis significant intra-individual differences in the spectral measurements with a high dynamic (20 dB difference corresponding to the factor 100 (10000%)), regarding the simulated status of stability in the prosthesis system.Conclusion
The results of the study demonstrate RFM as a highly sensitive non-invasive and non-traumatic method to support the application of RFM as a hip prosthesis monitoring procedure. The data obtained shows the possibility to use RFM for osteointegration surveillance and early detection of interface problems, but will require further evaluation in clinical and experimental studies. 相似文献76.
EM Maier J Pongratz AC Muntau B Liebl U Nennstiel-Ratzel U Busch R Fingerhut B Olgemöller AA Roscher W Röschinger 《Clinical genetics》2009,76(2):179-187
Medium‐chain acyl‐CoA dehydrogenase deficiency (MCADD) represents a potentially fatal fatty acid β‐oxidation disorder. Newborn screening (NBS) by tandem mass spectrometry (MS/MS) has been implemented worldwide, but is associated with unresolved questions regarding population heterogeneity, burden on healthy carriers, cut‐off policies, false‐positive and negative rates. In a retrospective case‐control study, 333 NBS samples showing borderline acylcarnitine patterns but not reaching recall criteria were genotyped for the two most common mutations (c.985A>G/c.199C>T) and compared with genotypes and acylcarnitines of 333 controls, 68 false‐positives, and 34 patients. c.985A>G was more frequently identified in the study group and false‐positives compared to controls (1:4.3/1:2.3 vs. 1:42), whereas c.199C>T was found more frequently only within the false‐positives (1:23). Biochemical criteria were devised to differentiate homozygous (c.985A>G), compound heterozygous (c.985A>G/c.199C>T), and heterozygous individuals. Four false‐negatives were identified because our initial algorithm required an elevation of octanoylcarnitine (C8) and three secondary markers in the initial and follow‐up sample. The new approach allowed a reduction of false‐positives (by defining high cut‐offs: 1.4 μmol/l for C8; 7 for C8/C12) and false‐negatives (by sequencing the ACADM gene of few suspicious samples). Our validation strategy is able to differentiate healthy carriers from patients doubling the positive predictive value (42→88%) and to target NBS to MCADD‐subsets with potentially higher risk of adverse outcome. It remains controversial, if NBS programs should aim at identifying all subsets of all diseases included. Because the natural course of milder variants cannot be assessed by observational studies, our strategy could serve as a general model for evaluation of MS/MS‐based NBS. 相似文献
77.
78.
79.
Effects of cholinergic modulation on responses of neocortical neurons to fluctuating input 总被引:1,自引:0,他引:1
Neocortical neurons in vivo are spontaneously active and intracellular
recordings have revealed strongly fluctuating membrane potentials arising
from the irregular arrival of excitatory and inhibitory synaptic
potentials. In addition to these rapid fluctuations, more slowly varying
influences from diffuse activation of neuromodulatory systems alter the
excitability of cortical neurons by modulating a variety of potassium
conductances. In particular, acetylcholine, which effects learning and
memory, reduces the slow alterhyperpolarization, which contributes to spike
frequency adaptation. We used whole-cell patch-clamp recordings of
pyramidal neurons in neocortical slices and computational simulations to
show, first, that when fluctuating inputs were added to a constant current
pulse, spike frequency adaptation was reduced as the amplitude of the
fluctuations was increased. High- frequency, high-amplitude fluctuating
inputs that resembled in vivo conditions exhibited only weak spike
frequency adaptation. Second, bath application of carbachol, a cholinergic
agonist, significantly increased the firing rate in response to a
fluctuating input but minimally displaced the spike times by < 3 ms,
comparable to the spike jitter observed when a visual stimulus is repeated
under in vivo conditions. These results suggest that cholinergic modulation
may preserve information encoded in precise spike timing, but not in
interspike intervals, and that cholinergic mechanisms other than those
involving adaptation may contribute significantly to cholinergic modulation
of learning and memory.
相似文献
80.
Abstract Protein-chemical and molecular studies were conducted on all osteogenesis imperfecta (OI) type III/IV patients referred to our hospital during the last 15 y. Of a total of 16 OI type III/IV patients studied, 15 patients were heterozygous for a mutation in one of the two genes coding for collagen I, COL1A1 or COL1A2. Cultured fibroblasts from these 15 patients produced both normal and abnormal collagen I molecules, pointing to a dominant-negative effect of the mutation. Nine mutations had not been described previously. Parental mosaicism was demonstrated in three families. In the 16th child the causative mutation was not found. In conclusion, OI type III/IV in most patients of Western European ancestry is caused by dominant mutations in the genes for collagen I, and recurrence of OI is caused in most cases by parental gonadal mosaicism. 相似文献