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91.
RATIONALE AND OBJECTIVES: To assess the accuracy of computed tomography (CT) in characterizing pleural fluid based on attenuation values. MATERIALS AND METHODS: Protocol was approved by the local institutional review board and informed consent was waived. We retrospectively analyzed 145 pleural effusions of 145 patients (mean/standard deviation age: 60.7/15.9 years; 69 females) who underwent CT of the thorax and diagnostic thoracentesis within 7 days of each other. Effusions were classified as transudates or exudates using laboratory markers based on Light's criteria. The mean Hounsfield units (HU) of an effusion was determined by a region of interest on the three slices with the greatest anteroposterior diameter. A receiver operating characteristic curve was constructed to determine threshold values for classification on the basis of mean HU and to examine overall accuracy, using the area under the curve (A(z)). RESULTS: Of the 101 exudates and 44 transudates, the mean attenuation of exudates (17.1 HU/standard deviation 4.4) was significantly higher than transudates (12.5 HU/6.3), (P < .001). There was a modest but significant positive relationship between mean HU and laboratory markers, with the strongest relationship with pleural/serum protein (r = 0.57, P < .001) and total pleural protein (r = 0.56, P < .001). The overall accuracy of attenuation values for identifying exudates was moderate, Az = 0.775, standard error = 0.039, with the largest limitation being the overlap with transudates in the 10-20 HU range, which constituted 66% (90/145) of the total effusions measured. CONCLUSION: Although the mean attenuation of exudates is significantly higher than transudates, the clinical use of CT numbers to characterize pleural fluid is not recommended, as their accuracy is only moderate. Moreover, there is a notable overlap in attenuation values between transudates and exudates for a majority of effusions. 相似文献
92.
Spinosa DJ Angle JF Hartwell GD Hagspiel KD Leung DA Matsumoto AH 《Radiologic clinics of North America》2002,40(4):693-710
Gadolinium is useful as an alternative contrast agent for diagnostic angiographic and interventional procedures in patients with renal insufficiency or a history of a severe reaction to iodinated contrast material. Gadolinium usually is used as a "problem solver" to answer specific diagnostic questions or guide interventional procedures that cannot adequately be defined with CO2 angiography. Because of dose limitations with Gd, careful planning is required prior to its use with angiography or interventional procedures. 相似文献
93.
Enhanced transcription factor DNA binding and gene expression induced by arsenite or arsenate in renal slices 总被引:5,自引:4,他引:1
Although the kidney represents a target for the accumulation and toxicity
of arsenic, little is known about the molecular targets of arsenic in this
organ. Therefore, these studies were designed to examine the molecular
impact of arsenite [As(III)] and arsenate [As(V)] at low (nanomolar)
concentrations. Precision-cut rabbit renal cortical slices were challenged
with As(III) or As(V) for up to 8 h. Neither form of the metal induced
overt cytotoxicity as assessed by intracellular K+ levels over this time
period at concentrations from 0.01-10 microM. In addition, no alterations
in the expression of Hsp 60, 70, or 90 were observed. However, induction of
heme oxygenase-1 (Hsp 32) was seen following a 4-h challenge with As(III),
but not with As(V). As(III) and As(V) induced DNA binding of AP-1 at 2- and
4-h exposure; following a 6-h exposure there was no difference. Although no
alteration in the DNA binding activity of ATF-2 was induced by As(III) or
As(V), both forms enhanced the DNA binding activity of Elk-1. Enhanced DNA
binding activity of AP-1 and Elk-1 correlated with increased gene
expression of c-fos, but not c-jun, at 2 h. c-myc gene expression was also
induced by As(III) and As(V), albeit at a later time point (6 h). These
results suggest that acute arsenic challenge, by either As(III) or As(V),
is associated with discrete alterations in the activity of signaling
pathways and gene expression in renal tissue.
相似文献
94.
95.
Mai VM Hagspiel KD Altes T Goode AR Williams MB Berr SS 《Journal of magnetic resonance imaging : JMRI》2000,11(2):97-102
Detection of regional perfusion deficit in the lung has been demonstrated using an arterial spin labeling technique called flow-sensitive alternating inversion recovery with an extra radiofrequency pulse (FAIRER). A pulmonary artery was occluded using a nondetachable balloon catheter to simulate an acute pulmonary embolism in 3 of 10 rabbits. Inflating the balloon occludes the artery, and deflating the balloon allows for reperfusion. Perfusion imaging was performed pre-occlusion, during occlusion, and after reperfusion. Signal enhancement due to perfusion of the pulmonary parenchyma was observed in the perfusion images with negligible artifacts. The perfusion deficit of the pulmonary parenchyma was detected distal to the site of occlusion in all three rabbits. Return of the pulmonary parenchymal perfusion was observed after reperfusion. Magnetic resonance imaging using FAIRER can detect signal loss due to absence of perfusion caused by pulmonary embolism. 相似文献
96.
Layman LC; Edwards JL; Osborne WE; Peak DB; Gallup DG; Tho SP; Reindollar RH; Roach DJ; McDonough PG; Lanclos KD 《Molecular human reproduction》1997,3(4):315-320
Women with recurrent abortion, primary unexplained infertility, and
gestational trophoblastic neoplasia (GTN) manifest disordered human
chorionic gonadotrophin (HCG) secretion. Mutations in the HCG
beta/luteinizing hormone (LH) beta gene complex could cause aberrant HCG
production in these disorders. The purpose of this study was to determine
whether HCG beta gene deletions occur in women with recurrent abortion or
primary unexplained infertility, and whether HCG beta gene duplications are
present in women with GTN. DNA was extracted from 10 patients with
unexplained recurrent abortion, 10 patients with unexplained primary
infertility, 12 patients with GTN, three partners of women with GTN, and 30
controls. Southern blots were constructed and hybridized with DNA probes
for HCG beta-5 and the LH beta gene. No gene deletions were identified in
patients with recurrent abortion or primary unexplained infertility.
Likewise, no gene duplications were identified in women with GTN. A
previously described Mbol restriction fragment length polymorphism (RFLP)
was identified in both patients and controls. A new Pstl RFLP was also
characterized, but was present in patients and controls.
Deletion/duplication mutations in the HCG beta/LH beta gene complex do not
appear to be common causes of aberrant HCG production in humans with these
disorders.
相似文献
97.
Strom TM; Hortnagel K; Hofmann S; Gekeler F; Scharfe C; Rabl W; Gerbitz KD; Meitinger T 《Human molecular genetics》1998,7(13):2021-2028
Wolfram syndrome is an autosomal recessive disorder characterized by
juvenile diabetes mellitus, diabetes insipidus, optic atrophy and a number
of neurological symptoms including deafness, ataxia and peripheral
neuropathy. Mitochondrial DNA deletions have been described in a few
patients and a locus has been mapped to 4p16 by linkage analysis.
Susceptibility to psychiatric illness is reported to be high in affected
individuals and increased in heterozygous carriers in Wolfram syndrome
families. We screened four candidate genes in a refined critical linkage
interval covered by an unfinished genomic sequence of 600 kb. One of these
genes, subsequently named wolframin, codes for a predicted transmembrane
protein which was expressed in various tissues, including brain and
pancreas, and carried loss-of- function mutations in both alleles in
Wolfram syndrome patients.
相似文献
98.
V M Mai Q Chen A A Bankier M Zhang K D Hagspiel S S Berr R R Edelman 《Magnetic resonance in medicine》2000,43(6):793-795
A technique is described for imaging pulmonary blood flow using a phase-sensitive selective inversion recovery (PS-SIR) sequence. PS-SIR image reconstruction provides excellent contrast, differentiating fully relaxed inflowing blood from inverted blood and lung tissue. The magnetization of the inverted tissues remains negative at any inversion delay less than that at which the magnetization of the lung tissue is nulled, whereas that of the fully relaxed inflowing blood is always positive. Pulmonary blood flow can be observed by tracking the propagation of the pixels with positive values. Five healthy volunteers were imaged. The normal pattern of blood flow advancing from the central arteries toward the peripheries and into the lung parenchyma with return toward the center via draining veins was depicted. The method offers promise for evaluating pulmonary blood flow without the need for image subtraction or contrast administration. Magn Reson Med 43:793-795, 2000. 相似文献
99.
100.
J. Fritz Angle Alan H. Matsumoto J. Kevin McGraw Klaus D. Hagspiel David J. Spinosa Christopher S. McCullough 《Cardiovascular and interventional radiology》1998,22(2):147-149
Percutaneous endovascular techniques were used to treat an arteriovenous fistula (AVF) associated with pancreatic transplantation.
A pancreatic transplant superior mesenteric artery-to-superior mesenteric-vein AVF was successfully embolized while flow to
the pancreas transplant was preserved. The embolization was aided by the use of Guglielmi detachable coils and a detachable
balloon. No complications were encountered. At 23 months follow-up, the patient is doing well with no recurrence. 相似文献