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101.
In vivo detection of iron and neuromelanin by transcranial sonography: a new approach for early detection of substantia nigra damage. 总被引:8,自引:0,他引:8
Luigi Zecca Daniela Berg Thomas Arzberger Petra Ruprecht Wolf D Rausch Massimo Musicco Davide Tampellini Peter Riederer Manfred Gerlach Georg Becker 《Movement disorders》2005,20(10):1278-1285
Early diagnosis of Parkinson's disease (PD) in nonsymptomatic patients is a key issue. An increased echogenicity of the substantia nigra (SN) was found previously in Parkinsonian patients and in a low percentage of healthy adults. These nonsymptomatic subjects also showed a reduced 18F-dopa uptake in striatum, suggesting a preclinical injury of the nigrostriatal system that could later proceed into PD. To investigate the ability of ultrasonography to detect markers of SN degeneration, such as iron deposition and neuromelanin depletion, we scanned postmortem brains from normal subjects at different ages by ultrasound and measured the echogenic area of the SN. The SN was then dissected and used for histological examinations and determination of iron, ferritin, and neuromelanin content. A significant positive correlation was found between the echogenic area of the SN and the concentration of iron, H- and L-ferritins. Multivariate analysis carried out considering the iron content showed a significant negative correlation between echogenicity and neuromelanin content of the SN. In PD, a typical loss of neuromelanin and increase of iron is observed in this brain area. The finding of a positive correlation between iron and ferritin levels and a negative correlation of neuromelanin content with the area of echogenicity at the SN could therefore provide an interesting basis for diagnosis and therapeutic follow-up studies in PD. 相似文献
102.
Orientation-specific relationship between populations of excitatory and inhibitory lateral connections in the visual cortex of the cat 总被引:11,自引:4,他引:7
The topography of lateral excitatory and lateral inhibitory connections was
studied in relation to orientation maps obtained in areas 17 and 18. Small
iontophoretic injections of biocytin were delivered to the superficial
layers in regions where orientation selectivity had been mapped using
electrode recordings of single- and multi-unit activity from various
cortical depths. Biocytin revealed extensive patchy axonal projections of
up to 3.5 mm in both areas while labelled somata occurred chiefly at the
injection site, indicating that the labelling was primarily anterograde.
Two types of boutons could be clearly distinguished: (i) putative
excitatory boutons either en passant or having a short stalk and (ii)
inhibitory boutons which were invariably of the basket-type.
Three-dimensional reconstructions of all labelled boutons showed that the
excitatory and the inhibitory networks had a distinctively different
relationship to orientation maps. The overall distribution of connections
showed that 53-59% of excitatory and 46-48% of inhibitory connections were
at iso-orientation, +/-30 degrees; oblique-orientation, +/-(30-60) degrees,
was shown by 30% of excitatory and 28-39% of inhibitory connections;
cross-orientation was shown by 11- 17% of excitatory and 15-24% of
inhibitory connections. Although excitatory patches occupied mainly
iso-orientation locations, interpatch regions representing chiefly
non-iso-orientations (oblique + cross orientation) were also innervated.
There was considerable overlap between the excitatory and inhibitory
network. Nonetheless, inhibitory connections were more common than
excitatory connections with non-iso- orientation locations. There was no
significant difference between the orientation topography of area 17 and
area 18 projections. The results suggest that in general the lateral
connectivity system is not orientation specific, but shows a moderate
iso-orientation preference for excitation and an even weaker
iso-orientation preference for inhibition. The broad orientation spectrum
of lateral connections could provide the basis for mechanisms that
requiring different orientations, as for example in detecting orientation
discontinuities.
相似文献
103.
Stephen M Auerbach Donald J Kiesler Jennifer Wartella Sarah Rausch Kevin R Ward Rao Ivatury 《American journal of critical care》2005,14(3):202-210
BACKGROUND: Families of critical care patients experience high levels of emotional distress. Access to information about patients' medical conditions and quality relationships with healthcare staff are high-priority needs for these families. OBJECTIVES: To assess satisfaction with needs met, signs and symptoms of acute stress disorder, interpersonal perception of healthcare staff, level of optimism, and the relationships among these variables in patients' family members. METHODS: Family representatives of 40 patients were administered a brief version of the Critical Care Family Needs Inventory, the Acute Stress Disorder Scale, the Brief Symptom Inventory, the Impact Message Inventory, and the Life Orientation Test shortly after admission of the patients to the intensive care unit and after discharge. RESULTS: Levels of dissociative symptoms associated with acute stress disorder were elevated in family members just after admission but decreased significantly after discharge. Needs the families thought were least satisfactorily cared for after admission involved lack of information. Interpersonally, attending physicians were viewed as more controlling than bedside nurses at admission; nurses were viewed as more affiliative than physicians both at admission and after discharge. At admission, higher optimism of the family members was strongly related to greater satisfaction with needs met, to perceptions of affiliation from physicians, and to perceptions of not being controlled by physicians. CONCLUSIONS: More interpersonal contact with medical staff can help meet the information needs of patients' families. Nurses may aid in families' adjustment by fostering a sense of optimism in family members and encouraging them to participate in the patients' care. 相似文献
104.
105.
Primary biliary carcinoma: CT evaluation 总被引:19,自引:0,他引:19
106.
107.
108.
Local cerebral metabolism during partial seizures 总被引:19,自引:0,他引:19
Interictal and ictal fluorodeoxyglucose scans were obtained with positron CT from four patients with spontaneous recurrent partial seizures, one with epilepsia partialis continua, and one with a single partial seizure induced by electrical stimulation of the hippocampus. Ictal metabolic patterns were different for each patient studied. Focal and generalized increased and decreased metabolism were observed. Ictal hypermetabolism may exceed six times the interictal rate and could represent activation of excitatory or inhibitory synapses in the epileptogenic region and its projection fields. Hypometabolism seen on ictal scans most likely reflects postictal depression and may indicate projection fields of inhibited neurons. No quantitative relationship between alterations in metabolism and EEG or behavioral measurements of ictal events could be demonstrated. 相似文献
109.
Thirteen patients who had undergone prolonged adrenocorticotropic hormone (ACTH) therapy for infantile spasms or myoclonic encephalopathy were examined with sonography. Nine patients were found to have appearances characteristic of medullary nephrocalcinosis. In each of these infants the cortical echogenicity was normal in the presence of focal areas of increased echogenicity within the renal pyramids. Five patients also showed a homogeneously increased echogenicity of the whole pancreas on sonography, and two of these showed increased density on computed tomography. Density measurements were in the range of calcific material within the papillae and pancreatic tissue. On abdominal survey radiographs, even in retrospect no calcifications could be recognized. 相似文献
110.