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991.
Kittner T Rudolf J Fages JF Legmann P Aschauer M Repa I Alvares MR Savalegui I Ittrich H Geterud K de Kevviler E Ayuso J Lockhart ME Blum A Iliasch H Leisinger G van Beek EJ Reid AW Brown JJ Yu TC Flamm SD Düber C Judmaier W Reimer P Stiskal M Kramann B Wolff S Blankenstein C 《European journal of radiology》2007,64(3):456-464
PURPOSE: To determine the most efficacious dose of gadodiamide for three-dimensional (3D) contrast-enhanced (CE) magnetic resonance angiography (MRA) of the renal arteries on a patient level based on the sensitivity in detecting the main hemodynamically relevant (> or =50% or occlusion) renal artery stenosis (RAS) using intra-arterial digital subtraction angiography (IA DSA) as the gold standard. MATERIALS AND METHODS: This prospective, randomized, double-blind, parallel-group, multicenter study included 273 patients referred to IA DSA for suspected RAS. Patients underwent 3D CE MRA after injection of 0.01, 0.05, 0.1, or 0.2mmol/kg of body weight gadodiamide (0.5mmol/ml). The images were assessed for location and degree of RAS by independent blinded readers (MRA: three readers, IA DSA: one reader). Hypothesis testing for a significant trend in sensitivity across dose groups was based on the one-sided Cochran-Armitage style trend test for each independent MRA reader. RESULTS: The lowest dose group (0.01mmol/kg) proved non-efficacious in detecting hemodynamically relevant (i.e., > or =50% or occlusion) RAS. A statistically significant dose trend (p<0.001) was shown for each of the three independent readers. Depending on reader, the sensitivity obtained with 0.05, 0.1, and 0.2mmol/kg was 63.9-86.1%, 75.8-91.4% and 80.6-90.6%, the specificity was 66.7-73.9%, 59.3-75.0%, and 59.3-75.0% and accuracy was 67.8-78.9%, 75.4-77.4%, and 76.3-81.0%, for the three dose groups, respectively. There were eight non-severe adverse events (AEs). Three serious AEs occurring in one patient were judged not related to gadodiamide by the on-site investigator. CONCLUSION: A significant dose trend between the four doses examined was observed. The lowest dose (0.01mmol/kg) differed significantly from those of the other three doses. Based on the analysis of the primary and secondary endpoints, 0.1mmol/kg gadodiamide appears to be the most suitable dose in diagnosing hemodynamically relevant RAS. The present study also demonstrated gadodiamide to be safe and well tolerated. 相似文献
992.
Lüdemann L Schmitt B Podrabsky P Schnackenburg B Böck J Gutberlet M 《European journal of radiology》2007,62(2):247-256
BACKGROUND: To present a new method for fully quantitative analysis of myocardial blood flow (MBF) using magnetic resonance imaging. The first pass of an intravascular iron oxide contrast medium can be used to quantify myocardial perfusion. The technique was validated in an animal model using colored microspheres. MATERIALS AND METHODS: In six pigs, a tracking catheter was positioned in the left anterior descending artery (LAD). Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed on a 1.5-T scanner using a hybrid gradient-echo/echoplanar imaging (GRE-EPI) sequence. Regional myocardial blood flow (rMBF) was altered by either inducing vasodilatation with adenosine or creating coronary artery obstruction. The T(1) effect of a superparamagnetic iron oxide-based contrast medium (Resovist) administered at a dose of 8 micromol/kg was used. Upslope, time-to-peak and peak intensity were calculated from the signal intensity-time curves and absolute rMBF using the Kety-Schmidt equation; results were compared to those obtained using colored microspheres. RESULTS: The mean rMBF calculated by MRI was 1.49 (+/-6.91, quartile width) ml/min/g versus 3.21 (+/-1.61) ml/min/g measured by means of microspheres under resting conditions. rMBF increased to a mean of 6.21 (+/-2.83) ml/min/g versus 4.22 (+/-1.70) ml/min/g under adenosine and was reduced to zero flow in total occlusion. Linear regression showed the best correlation for upslope (R=0.714), time-to-peak (R=0.626) and the Kety-Schmidt equation (R=0.584). CONCLUSIONS: The T(1) effect of an iron oxide-based contrast medium allows determination of rMBF when using the Kety-Schmidt equation. The results are similar to those obtained with the standard of reference, colored micropheres, but not better than the results of the semiquantitative approach. 相似文献
993.
Pouleur AC le Polain de Waroux JB Kefer J Pasquet A Coche E Vanoverschelde JL Gerber BL 《European radiology》2007,17(12):3199-3207
Preoperative identification of significant coronary artery disease (CAD) in patients prior to valve surgery requires systematic
invasive coronary angiography. The purpose of this current prospective study was to evaluate whether exclusion of CAD by multi-detector
CT (MDCT) might potentially avoid systematic cardiac catheterization in these patients. Eighty-two patients (53 males, 62 ± 13 years)
scheduled to undergo valve surgery underwent 40-slice MDCT before invasive quantitative coronary angiography (QCA). According
to QCA, 15 patients had CAD (5 one-vessel, 6 two-vessel and 4 three-vessel disease). The remaining 67 patients had no CAD.
On a per-vessel basis, MDCT correctly identified 27/29 (sensitivity 93%) vessels with and excluded 277/299 vessels (specificity
93%) without CAD. On a per-patient basis, MDCT correctly identified 14/15 patients with (sensitivity 93%) and 60/67 patients
without CAD (specificity 90%). Positive and negative predictive values of MDCT were 67% and 98%. Performing invasive angiography
only in patients with abnormal MDCT might have avoided QCA in 60/82 (73%). MDCT could be potentially useful in the preoperative
evaluation of patients with valve disease. By selecting only those patients with coronary lesions to undergo invasive coronary
angiography, it could avoid cardiac catheterization in a large number of patients without CAD.
This work was supported by a grant of the Fondation Nationale de la Recherche Scientifique of the Belgian Government (FRSM
3.4557.02). Dr. Pouleur is supported by a personal grant of the Fondation Nationale de la Recherche Scientifique of the Belgian
Government. 相似文献
994.
Peripheral nerve tumors are not frequent, but due to their association with a nerve they are somewhat special. They may be
encountered incidentally during evaluation of a soft-tissue mass or when a nerve lesion is clinically suspected and the recognition
of such a lesion and its differential diagnosis is key for successful therapy and patient prognosis. As sonography is often
the first line modality in the work-up of a soft-tissue mass, the sonographer should be aware of the typical features of such
lesions in order to arrive at the correct diagnosis, and this article tries to give an overview of the histological subtypes
of peripheral nerve tumors and their sonographic characteristics. 相似文献
995.
Jahnke C Nehrke K Paetsch I Schnackenburg B Gebker R Fleck E Nagel E 《Journal of magnetic resonance imaging : JMRI》2007,26(3):780-786
PURPOSE: To evaluate the impact of a new, cross-correlation based method for compensation of respiratory induced motion of the heart using an individually adapted three-dimensional (3D) translation or affine transformation approach. MATERIALS AND METHODS: A total of 32 patients underwent a routine cardiac MR examination. In each patient, a calibration scan was performed during free-breathing to register breathing-related motion within a 3D ellipsoid registration kernel covering the entire heart. Three navigators were employed for all three spatial dimensions (feet-head, anterior-posterior, and left-right) and the optimal translatory correction factors for each spatial dimension were determined. In addition, the cross-correlations for different motion models (no compensation, fixed 1D-translation, adapted 3D-translation, and affine transformation) were calculated. RESULTS: The mean correction factor for the feet-head direction was 0.45 +/- 0.13. Though the mean correction factors for the anterior-posterior and left-right direction were nearly zero (-0.01 +/- 0.08 and 0.02 +/- 0.09, respectively), the correction factors exceeded the amount of 0.1 in 12 (19%) and in 19 patients (30%), respectively. All motion compensation models showed significantly higher cross-correlations when compared to "no compensation" (P < 0.05). In particular, the affine transformation algorithm achieved the highest cross-correlation values (88.3 +/- 5.1%) with a significant increase compared to fixed 1D translation (84.7 +/- 6.5%, P < 0.05). CONCLUSION: A considerable number of patients demonstrated relevant breathing-related movement of the heart in the anterior-posterior or left-right direction in addition to the predominant breathing-related movement in the feet-head direction. Thus, it is recommended to compensate for all three spatial dimensions. The affine transformation algorithm combined with three navigators significantly improved breathing-related cardiac motion compensation when compared to the conventionally applied 1D translation with a fixed correction factor. 相似文献
996.
Gertz SD Bodmann BG Vela D Papadakis M Aboshady I Cherukuri P Alexander S Kouri DJ Baid S Gittens AA Gladish GW Conyers JL Cody DD Gavish L Mazraeshahi RM Wilner WT Frazier L Madjid M Zarrabi A Lukovenkov S Ahmed A Willerson JT Casscells SW 《Academic radiology》2007,14(12):1509-1519
RATIONALE AND OBJECTIVES: The capability of wavelet transforms to separate signals into frequency bands is the basis for its use in image compression and storage, data management and transmission, and, recently, extraction of latent images of tissue components from noisy medical images. Analysis of temporal variations of radiofrequency backscatter of intravascular ultrasound with one-dimensional wavelets can detect lipid-laden plaque in coronary arteries with a sensitivity and specificity of >80%. In this study we evaluate the capability of a novel, 3-dimensional isotropic wavelet analysis to perform high resolution, non-directionally biased, statistically reliable, non-invasive discrimination between components of human coronary atherosclerotic plaques in micro-CT. MATERIALS AND METHODS: Coronary artery segments (5-15 mm) were excised at necropsy from 18 individuals with advanced coronary atherosclerosis. Specimens were imaged using a GE Locus SP ex vivo micro-CT scanner and processed for histological correlation (833 sections). The isotropic wavelet constructs were applied to the entire volume of CT data of each arterial segment to distinguish tissue textures of varying scales and intensities. Voxels were classified and plaque characterization achieved by comparing the relative magnitudes of these wavelet constituents to that of several reference plaque tissue components. RESULTS: Processing of micro-CT images via these isotropic wavelet algorithms permitted 3-D, color-coded, high resolution, digital discrimination between lumen, calcific deposits, lipid-rich deposits, and fibromuscular tissue providing detail not possible with conventional thresholding based on Hounsfield intensity units. Using the isotropic wavelets (with histology as the gold standard), lipid-rich pools approaching the size of the filter for the isotropic wavelet algorithm (0.25 mm [250 microns] in length) were identified with 81% sensitivity and 86% specificity. Calcific deposits, fibromuscular tissue, and lumen equal to or larger than the wavelet filter size were detected without error (100% sensitivity and specificity). CONCLUSION: Isotropic wavelet analysis permits high resolution, multi-dimensional identification of coronary atherosclerotic plaque components in micro-CT with sensitivity and specificity similar to that achieved with data obtained invasively (from IVUS in vivo) using one-dimensional wavelets. Further studies are necessary to test the applicability of this technology to clinical, multi-detector scanners. 相似文献
997.
Novotny A Emmanuel K Matevossian E Kriner M Ulm K Bartels H Holzmann B Weighardt H Siewert JR 《American journal of surgery》2007,194(1):35-39
BACKGROUND: To develop strategies for the prediction of sepsis outcome systemic procalcitonin (PCT) levels were correlated with various clinical parameters. METHODS: PCT levels and Acute Physiology and Chronic Health Evaluation (APACHE) II scores were assessed on the day of sepsis diagnosis in a large series (n = 160) of patients developing sepsis after major visceral surgery. RESULTS: In multivariate analysis, systemic PCT and the APACHE II score could be identified as independent early predictive indicators of lethal sepsis. Combining both indicators at sepsis onset, a prognosis score could be calculated using binary logistic regression analysis allowing the identification of high- and low-risk groups. While 71% of the high-risk patients died of sepsis, 77% of patients assigned to the low-risk group survived the septic complication (sensitivity 71%, specificity 77%). CONCLUSION: Calculation of the prognosis-score allowed for an early prediction of the septic course with high sensitivity and specificity. This information could aid in deciding on adequate treatment strategies. 相似文献
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