全文获取类型
收费全文 | 13766篇 |
免费 | 747篇 |
国内免费 | 93篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 323篇 |
妇产科学 | 242篇 |
基础医学 | 1906篇 |
口腔科学 | 363篇 |
临床医学 | 1211篇 |
内科学 | 3696篇 |
皮肤病学 | 225篇 |
神经病学 | 1278篇 |
特种医学 | 514篇 |
外科学 | 2021篇 |
综合类 | 46篇 |
一般理论 | 4篇 |
预防医学 | 654篇 |
眼科学 | 193篇 |
药学 | 737篇 |
中国医学 | 28篇 |
肿瘤学 | 1048篇 |
出版年
2023年 | 89篇 |
2022年 | 195篇 |
2021年 | 369篇 |
2020年 | 263篇 |
2019年 | 299篇 |
2018年 | 397篇 |
2017年 | 293篇 |
2016年 | 335篇 |
2015年 | 403篇 |
2014年 | 556篇 |
2013年 | 711篇 |
2012年 | 1115篇 |
2011年 | 1099篇 |
2010年 | 648篇 |
2009年 | 571篇 |
2008年 | 937篇 |
2007年 | 940篇 |
2006年 | 897篇 |
2005年 | 873篇 |
2004年 | 809篇 |
2003年 | 664篇 |
2002年 | 640篇 |
2001年 | 106篇 |
2000年 | 90篇 |
1999年 | 116篇 |
1998年 | 122篇 |
1997年 | 101篇 |
1996年 | 105篇 |
1995年 | 75篇 |
1994年 | 70篇 |
1993年 | 52篇 |
1992年 | 48篇 |
1991年 | 61篇 |
1990年 | 39篇 |
1989年 | 41篇 |
1988年 | 37篇 |
1987年 | 40篇 |
1986年 | 33篇 |
1985年 | 36篇 |
1984年 | 50篇 |
1983年 | 41篇 |
1982年 | 33篇 |
1981年 | 29篇 |
1980年 | 19篇 |
1979年 | 16篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 14篇 |
1975年 | 16篇 |
1974年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
Claudio Babiloni Giovanni Frisoni Mircea Steriade Lorena Bresciani Giuliano Binetti Claudio Del Percio Cristina Geroldi Carlo Miniussi Flavio Nobili Guido Rodriguez Filippo Zappasodi Tania Carfagna Paolo M Rossini 《Clinical neurophysiology》2006,117(5):1113-1129
OBJECTIVE: A relationship between brain atrophy and delta rhythmicity (1.5-4 Hz) has been previously explored in Alzheimer's disease (AD) subjects [Fernandez A, Arrazola J, Maestu F, Amo C, Gil-Gregorio P, Wienbruch C, Ortiz T. Correlations of hippocampal atrophy and focal low-frequency magnetic activity in Alzheimer disease: volumetric MR imaging-magnetoencephalographic study. Am J Neuroradiol. 2003 24(3):481-487]. In this study, we tested the hypothesis that such a relationship does exist not only in AD patients but also across the continuum of subjects with mild cognitive impairment (MCI) and AD. METHODS: Resting, eyes-closed EEG data were recorded in 34 MCI and 65 AD subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. Cortical EEG sources were correlated with MR-based measurements of lobar brain volume (white and gray matter). RESULTS: A negative correlation was observed between the frontal white matter and the amplitude of frontal delta sources (2-4 Hz) across MCI and AD subjects. CONCLUSIONS: These results confirmed for the first time the hypothesis that the sources of resting delta rhythms (2-4 Hz) are correlated with lobar brain volume across MCI and AD subjects. SIGNIFICANCE: The present findings support, at least at group level, the 'transition hypothesis' of brain structural and functional continuity between MCI and AD. 相似文献
42.
Everson L. A. Artifon Airton Z. Rodrigues Sergio Marques Bhawna Halwan Paulo Sakai Claudio Bresciani Atul Kumar 《Journal of gastrointestinal surgery》2007,11(12):1686-1691
Background Exploratory laparoscopy is commonly undertaken in patients with highly suspicious biliary and pancreatic lesions to facilitate
diagnosis and staging cancer is present. If an unresectable tumor is identified, a second endoscopic procedure may be required
do deploy a self-expandable metal stent (SEMS) for palliation. As endoscopic retrograde cholangio pancreatography (ERCP) may
be unsuccessful in up to 20% of patients, we evaluated the feasibility and safety of deployment of self-expandable metal stents
at the same time as the initial laparoscopy.
Patients and Methods A total of 23 eligible patients (8 male and 15 female) with malignant obstruction of the common bile duct underwent deployment
of SEMS at laparoscopy. Primary outcome measure was the successful laparoscopic deployment of stent and secondary outcome
measure was complications rates.
Results Indications for stent deployment were unresectable pancreatic cancer in 18, cholangiocarcinoma in two, neuroendocrine tumor
in one and ampullary adenocarcinoma in two patients. The median age was 73 years (range 49–93). Twenty-two of 23 stents were
deployed successfully: 17 stents were deployed transcystically and five via a choledochotomy. Median times for laparoscopic
exploration and SEMS deployment were 165 min (range 105–230) and 20 min (range 10–50), respectively. Pre- and post-procedures
median total bilirubin were 9.4 mg/dl (range 5.4–17.5) and 4.0 (range 2.6–7.1). The median size of the pancreatic mass was
3 cm (range 2–5 cm) and that of the common bile duct (CBD) from 9.2 mm (range 7.2–17.4). The mean duration of laparoscopy
was 170 min (range 120–230 min) and that for stent deployment 23 min (range 10–50 min). Complications included bleeding, obstruction,
and wound infection. Bleeding occurred on day 7 in two patients and on day 30 in one patient; bleeding occurred at the gastrojejunal
anastomosis site and was successfully treated with endoscopic hemostasis. A total of three stent obstructions were identified:
one each at 60, 90, and 120 days follow-up. All complications were successfully managed endoscopically. There were a total
of seven deaths, six as a result of progressive cancer and one of surgical wound infection and ensuing complications.
Conclusion This study demonstrates that laparoscopic deployment of self-expandable metal bile duct stents is feasible and safe. This
option appears to be a reasonable option in patients with inoperable malignant obstruction of the distal common bile duct. 相似文献
43.
Claudio Babiloni Rosanna Squitti Claudio Del Percio Emanuele Cassetta Maria Carla Ventriglia Florinda Ferreri Mario Tombini Giovanni Frisoni Giuliano Binetti Mariella Gurzi Serenella Salinari Filippo Zappasodi Paolo M Rossini 《Clinical neurophysiology》2007,118(6):1244-1260
OBJECTIVE: The present study tested the hypothesis that the serum copper abnormalities were correlated with alterations of resting electroencephalographic (EEG) rhythms across the continuum of healthy elderly (Hold), mild cognitive impairment (MCI), and AD subjects. METHODS: Resting eyes-closed EEG rhythms delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), beta 2 (20-30Hz), and gamma (30-40Hz), estimated by LORETA, were recorded in 17 Hold, 19 MCI, 27 AD- (MMSE< or =20), and 27 AD+ (MMSE20) individuals and correlated with copper biological variables. RESULTS: Across the continuum of Hold, MCI and AD subjects, alpha sources in parietal, occipital, and temporal areas were decreased, while the magnitude of the delta and theta EEG sources in parietal, occipital, and temporal areas was increased. The fraction of serum copper unbound to ceruloplasmin positively correlated with temporal and frontal delta sources, regardless of the effects of age, gender, and education. CONCLUSIONS: These results sustain the hypothesis of a toxic component of serum copper that is correlated with functional loss of AD, as revealed by EEG indexes. SIGNIFICANCE: The present study represents the first demonstration that the fraction of serum copper unbound to ceruloplasmin is correlated with cortical delta rhythms across Hold, MCI, and AD subjects, thus unveiling possible relationships among the biological parameter, advanced neurodegenerative processes, and synchronization mechanisms regulating the relative amplitude of selective EEG rhythms. 相似文献
44.
Antonio D'Andrilli Anna Maria Ciccone Federico Venuta Mohsen Ibrahim Claudio Andreetti Domenico Massullo Rita Formisano Erino A Rendina 《European journal of cardio-thoracic surgery》2008,33(3):440-443
OBJECTIVE: We report the long-term results of our 16-year experience with laryngotracheal resection for benign stenosis. METHODS: Between 1991 and 2006, 35 consecutive patients (19 males, 16 females) underwent laryngotracheal resection for subglottic postintubation (32) or idiopathic (3) stenosis. Mean age was 43 years (range 14-71). At the time of surgery 13 patients presented with tracheostomy and 7 with a Dumon stent. The upper limit of the stenosis was from 0.6 to 1.5 cm below the vocal cords. The length of airway resection ranged between 1.5 and 6 cm. Suprahyoid release was performed in two patients and pericardial release in one. Nine patients had psychiatric and/or neurological post-coma disorders. Mean follow-up is over 5 years (61 months; range 3-194). RESULTS: There was no perioperative mortality. Thirty patients (85.7%) had excellent or good anatomic and functional results. Four patients (11.4%) presented restenosis at a distance of 25-110 days from the operation. Restenosis was successfully treated by endoscopic procedures in all four patients. One patient (2.9%) presented anastomotic dehiscence that required temporary tracheostomy closed after 1 year with no sequelae. Three patients (8.4%) had wound infection. Long-term follow-up was uneventful also in patients who had early complications. CONCLUSIONS: Long-term follow-up confirms that laryngotracheal resection is the definitive curative treatment for benign subglottic stenosis. Surgical complications can be successfully managed by non-operative procedures. Despite the occurrence of early complications, excellent and stable results can still be obtained at long term. 相似文献
45.
Vittorio Petraccone Finizia Auriemma Francesco Dal Poggetto Claudio De Rosa Gaetano Guerra Paolo Corradini 《Macromolecular chemistry and physics.》1993,194(5):1335-1345
In this contribution, the X-ray diffraction (XRD) pattern of a highly oriented sample of syndiotactic polystyrene in the mesomorphic form, collected by an automatic diffractometer, is presented, thus providing quantitative and more complete information relative to the diffracted intensity. The structural changes induced by annealing procedures in mesomorphic samples are shown through the analysis of the XRD patterns: both unoriented and oriented mesomorphic samples are transformed gradually into α-form crystals. On the basis of these evidences and of preliminary comparisons between the calculated Fourier transform of simplified models and the experimental diffraction intensity, it is suggested that the local organization in triplets of trans-planar chains, typical of the different modifications of the α-form, would be largely present also in the disordered chain agglomerates of the mesomorphic form. 相似文献
46.
47.
Myocardial protection in adult cardiac surgery: current options and future challenges 总被引:3,自引:0,他引:3
Francesco Nicolini Cesare Beghi Claudio Muscari Andrea Agostinelli Alessandro Maria Budillon Igino Spaggiari Tiziano Gherli 《European journal of cardio-thoracic surgery》2003,24(6):986-993
Current techniques of myocardial protection are evolving with the use of less conventional modalities of cardioplegia and have reduced the morbidity and mortality of cardiac operations. Blood cardioplegic solutions appear superior to cold cardioplegia in terms of myocardial protection and adjuncts as glutamate/aspartate enhancement, antioxidant supplementation, nitric oxide donors and maintenance of calcium homeostasis seem effective. In the near future, further experimental and clinical investigations about pharmacological preconditioning, sodium–hydrogen exchangers inhibition and gene therapy need to be addressed to well define their potential role in the improvement of current techniques of myocardial protection that are suboptimal in high-risk clinical settings. 相似文献
48.
Etienne Pralong Claudio Pollo Jean-Guy Villemure Damien Debatisse 《Movement disorders》2007,22(13):1879-1884
Besides clinical efficacy, the mechanisms of action of deep brain stimulation (DBS) are still debated. To shed light on this complex issue, we have taken the opportunity to record the response of globus pallidus internus (GPi) neurones to 100 Hz stimulations in a case of Lesch-Nyhan syndrome (LNS) where four pallidal electrodes were implanted. Three types of response were observed, 2/19 neurones were unaffected by DBS. About 7/19 neurones were inhibited during DBS stimulation and 10/19 neurones were excited during DBS stimulation. Both effects ceased when DBS was turned off. Inhibited neurones were situated lower that exited ones on the trajectory (1.25 and 4.65 mm above the center of GPi respectively). These observations suggest that locally DBS induces a reversible inhibition of neurone firing rate while at the same time distantly exciting the main afferents to and/or efferents from the GPi. Both actions would result in a strong GPi inhibition that does not preclude increased outflow from the GPi. 相似文献
49.
Claudio Franceschi MD 《Nutrition reviews》2007,65(S3):S173-S176
Widespread aging at the population level is a recent phenomenon that emerged in affluent societies. Inflammation is necessary to cope with damaging agents and is crucial for survival, particularly to cope with acute inflammation during our reproductive years. But chronic exposure to a variety of antigens, especially to some viruses such as cytomegalovirus, for a period much longer than that predicted by evolution, induces a chronic low-grade inflammatory status that contributes to age-associated morbidity and mortality. This condition carries the proposed name "inflammaging". Centenarians are unique in that, despite high levels of pro-inflammatory markers, they also exhibit anti-inflammatory markers that may delay disease onset. The key to successful aging and longevity is to decrease chronic inflammation without compromising an acute response when exposed to pathogens. 相似文献
50.