全文获取类型
收费全文 | 178983篇 |
免费 | 1135篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 1229篇 |
儿科学 | 6713篇 |
妇产科学 | 3090篇 |
基础医学 | 17084篇 |
口腔科学 | 1603篇 |
临床医学 | 12603篇 |
内科学 | 31780篇 |
皮肤病学 | 849篇 |
神经病学 | 16595篇 |
特种医学 | 8956篇 |
外科学 | 29280篇 |
综合类 | 2314篇 |
一般理论 | 1篇 |
预防医学 | 18188篇 |
眼科学 | 2756篇 |
药学 | 9690篇 |
中国医学 | 632篇 |
肿瘤学 | 16780篇 |
出版年
2023年 | 44篇 |
2022年 | 62篇 |
2021年 | 122篇 |
2020年 | 77篇 |
2019年 | 123篇 |
2018年 | 21998篇 |
2017年 | 17432篇 |
2016年 | 19592篇 |
2015年 | 986篇 |
2014年 | 888篇 |
2013年 | 885篇 |
2012年 | 7204篇 |
2011年 | 21244篇 |
2010年 | 18954篇 |
2009年 | 11656篇 |
2008年 | 19704篇 |
2007年 | 21927篇 |
2006年 | 788篇 |
2005年 | 2431篇 |
2004年 | 3642篇 |
2003年 | 4571篇 |
2002年 | 2756篇 |
2001年 | 296篇 |
2000年 | 426篇 |
1999年 | 195篇 |
1998年 | 240篇 |
1997年 | 246篇 |
1996年 | 143篇 |
1995年 | 135篇 |
1994年 | 127篇 |
1993年 | 85篇 |
1992年 | 50篇 |
1991年 | 98篇 |
1990年 | 136篇 |
1989年 | 87篇 |
1988年 | 67篇 |
1987年 | 50篇 |
1986年 | 37篇 |
1985年 | 37篇 |
1984年 | 25篇 |
1983年 | 29篇 |
1982年 | 33篇 |
1980年 | 47篇 |
1974年 | 26篇 |
1938年 | 60篇 |
1937年 | 25篇 |
1935年 | 22篇 |
1934年 | 30篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Edward D. Nicol James Stirrup Eliana Reyes Michael Roughton Simon P. G. Padley Michael B. Rubens S. Richard Underwood 《Journal of nuclear cardiology》2008,15(4):497-502
Background. Cardiac computed tomography (CCT) has the potential to assess both coronary anatomy and ventricular function in a single
study. We examined the agreement between CCT and myocardial perfusion scintigraphy (MPS) for the assessment of global and
regional ventricular function.
Methods and Results. Research CCT was performed in 52 patients with a low to intermediate likelihood of coronary artery disease referred for
MPS. Left ventricular enddiastolic volume, left ventricular end-systolic volume, left ventricular ejection fraction (LVEF),
and myocardial wall motion and thickening were compared between techniques. In addition, myocardial contrast attenuation on
CCT was compared with radiotracer uptake on MPS. LVEF values agreed well (mean difference, 4.1%; SD, 15.13%), but CCT left
ventricular end-diastolic volume was greater compared with MPS (mean difference, 46.0 mL; SD, 33.34 mL) (P<.001). There was moderate agreement for segmental myocardial motion and thickening, with κ values of 0.57 (95% confidence
interval, 0.51–0.63) and 0.47 (95% confidence interval, 0.41–0.53), respectively. Seventeen patients had hypoattenuation in
at least 1 myocardial segment on CCT. Three of four patients with concomitant abnormalities of wall motion and thickening
on CCT had infarction in the same territory on MPS.
Conclusions. There was good agreement for LVEF between CCT and MPS but myocardial volumes differed, and these modalities cannot be used
interchangeably. Mild abnormalities of regional function are detected more commonly by CCT than by MPS. Myocardial hypoattenuation
on CCT is highly specific for myocardial infarction when associated with reduction of systolic wall thickening and regional
wall motion abnormality.
Dr Nicol received a grant from the Defence Postgraduate Medical Deanery. 相似文献
992.
Clinical and structural results of partial supraspinatus tears treated by subacromial decompression without repair 总被引:1,自引:0,他引:1
Dennis Liem Semra Alci Nicolas Dedy Jörn Steinbeck Björn Marquardt Gunnar Möllenhoff 《Knee surgery, sports traumatology, arthroscopy》2008,16(10):967-972
Patients with primary impingement and articular sided partial tears of the supraspinatus are often treated by subacromial
decompression without repair, if the extent of the tear is estimated to be below 50% of tendon thickness. It has been questioned
whether repair of these cuff lesions is necessary, because these tears could progress to full thickness tears with deteriorating
clinical results. Our hypothesis was that subacromial decompression without repair of the supraspinatus tendon leads to significant
clinical improvement for patients with grade I and II articular sided tears without progression to a full thickness tear on
a regular basis. 46 consecutive patients (av. Age 59.2 years, range 33–76.6 years) were retrospectively reviewed after an
average follow up of 50.3 months (36–86 months). 26 patients (43.5%) had a grade I tear according to Ellman, which was left
alone, 20 patients suffered from a grade II tear, which was debrided. Clinical outcome was assessed with the ASES Score and
ultrasound evaluation was performed on all patients to detect possible progression to a full thickness tear. The average ASES
Score significantly improved from 37.4 to 86.6 points (p < 0.0001). The mean postoperative Constant Score was 87.6 points. Only three patients (6.5%) progressed to a full thickness
tear detectable on ultrasound examination. Only one of these patients had a poor result with an ASES Score of 35 points, the
other two were very satisfied and had an ASES score above 90 points. 8 patients showed no more signs of partial tearing on
ultrasound and these patients had an average ASES Score of 93.1 points. Overall clinical outcome was rated excellent in 35
cases (76.1%), good in 5 (10.9%), average in 2 (4.3%) and poor in 4 (8.7%). Our results indicate that good and excellent results
can be achieved mid- to long term by acromioplasty without repair of the rotator cuff in articular sided partial tears grade
I and II. These results reach almost 95% of the value of a healthy shoulder. A better result on ultrasound examination was
associated with a superior clinical outcome, while progression to a full thickness tear was rare. 相似文献
993.
Frederick Michels Stéphane Guillo Ana King Stéphane Jambou Christophe de Lavigne 《Knee surgery, sports traumatology, arthroscopy》2008,16(11):1043-1046
Endoscopic calcaneoplasty is a minimally invasive technique for resection of inflamed retrocalcaneal bursa as well as the
posterosuperior part of the calcaneus. A relative contra-indication for this technique is a tear of the Achilles tendon. In
this report, we describe the treatment of a patient with Haglund’s deformity associated with a tear of the Achilles tendon.
Both the lesions are treated endoscopically. The technique is described and the pitfalls are discussed. 相似文献
994.
Limouris GS Chatziioannou A Kontogeorgakos D Mourikis D Lyra M Dimitriou P Stavraka A Gouliamos A Vlahos L 《European journal of nuclear medicine and molecular imaging》2008,35(10):1827-1837
Purpose The aim of this study is to evaluate the effectiveness of 111In-DTPA-Phe1-octreotide infusions after selective catheterization of the hepatic artery in inoperable metastasised liver, sst2 receptor-positive neuroendocrine tumours due to the effect of 111In Auger electron emission, minimising in parallel the toxicity of non-target tissue.
Methods The average dose per session administered monthly to each patient (17 cases in total) was 6.3 ± 2.3 GBq. Repetitions did not
exceed 12-fold, except in one case (15 sessions). Response assessment was classified according to the Response Evaluating
Criteria in Solid Tumours. CT/MRI scans were performed as baseline before, during and after the end of treatment, and monthly
ultrasound images for follow-up measurements. Toxicity (World Health Organization criteria) was measured using blood and urine
tests of renal, hepatic and bone marrow function.
Results Complete response was achieved in one (5.9%) patient and partial in eight (47.0%), and disease stabilization in 3 (17.7%)
patients; five (29.4%) did not respond. A 32-month median survival time was estimated in 12 (70.5%). Nine of these 12 surviving
had a mean target diameter shrinkage from 144 ± 81 to 60 ± 59 mm. Grade 1 erythro-, leuko- and thrombo-cytopenia occurred
in three (17.6%) cases.
Conclusion In unresectable metastatic liver lesions positive for somatostatin receptors repeated, transhepatic high doses of 111In-DTPA-Phe1-octreotide show an effective therapeutic outcome. Given the locoregional modality character of the administration technique
plus the extremely short range of 111In Auger and internal conversion electrons emission, no nephro-, liver- or myelo-toxicity has so far been observed. 相似文献
995.
Comparison of grey matter and metabolic reductions in frontotemporal dementia using FDG-PET and voxel-based morphometric MR studies 总被引:1,自引:0,他引:1
Kanda T Ishii K Uemura T Miyamoto N Yoshikawa T Kono AK Mori E 《European journal of nuclear medicine and molecular imaging》2008,35(12):2227-2234
Purpose The aim of this study was to investigate the regional differences between the morphologic and functional changes in the same
patients with frontotemporal dementia (FTD) using statistical parametric mapping and voxel-based morphometry (VBM).
Methods Thirteen FTD patients (mean age, 64.9 years old; mean MMSE score, 17.7), 20 sex-matched Alzheimer’s disease (AD) patients
(mean age, 65.0 years old; mean MMSE score, 17.5), and 20 normal volunteers (mean age, 65.2 years old; mean MMSE score, 29.0)
underwent both [18F]FDG positron emission tomography and three-dimensional spoiled gradient echo MRI. Statistical parametric mapping was used
to conduct a VBM analysis of the morphologic data, which were compared voxel by voxel with the results of a similar analysis
of glucose metabolic data.
Results FTD patients showed decreased grey matter volume and decreased glucose metabolism in the frontal lobe and anterior temporal
lobe. In addition, there was a clear asymmetry in grey matter volume in FTD patients by the VBM analysis while the glucose
metabolic data showed little asymmetry. In AD patients, glucose metabolic reduction occurred in the bilateral posterior cingulate
gyri and parietal lobules while grey matter density decreased the least in the same patients.
Conclusion In FTD, metabolic and morphologic changes occur in the bilateral frontal lobe and temporal lobe with a limited asymmetry whereas
there was considerable discordance in the AD group. 相似文献
996.
Akira Sato Kazutaka Aonuma Toshihiro Nozato Yukio Sekiguchi Osamu Okazaki Kazuo Kubota Michiaki Hiroe 《Journal of nuclear cardiology》2008,15(5):671-679
Background. This study was designed to assess the influence of coronary endothelial function and the serial changes of dual myocardial
single photon emission computed tomography (SPECT) imaging in transient left ventricular (LV) apical ballooning.
Methods and Results. We evaluated 35 consecutive patients (8 men and 27 women; mean age, 71 ±13 years) with transient LV apical ballooning. All
patients underwent coronary angiography with acetylcholine provocation 1 month after onset. Iodine 123 β-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) and thallium 201 dual myocardial SPECT was serially performed on day 1 of admission
and 1 month and 6 months later. In 8 of 35 patients (23%), epicardial coronary spasm was induced by acetylcholine infusion.
At the peak acetylcholine dose (100 μg), diffuse coronary vasoconstriction developed in 19 of 35 patients (54%). Of 19 patients,
13 had diffuse coronary vasoconstriction with chest pain and ST-segment depression. The total defect score of I-123 BMIPP
and Tl-201 SPECT showed marked perfusion-fatty acid metabolic mismatches (13.7±3.6 vs 8.7±2.3, P<.001) at the LV apex during the acute phase but few mismatched areas (2.1±1.1 vs 1.5±1.4, P = not significant) at 6 months.
Conclusions. Transient LV apical ballooning might be caused by stress-induced coronary epicardial spasm or endothelial dysfunction, resulting
in myocardial stunning. 相似文献
997.
Amit R. Patel Frederick H. Epstein Christopher M. Kramer 《Journal of nuclear cardiology》2008,15(5):698-708
Conclusion In this review we have examined the role of perfusion CMR for evaluating the integrity and function of the microcirculation.
We have discussed the techniques for fully quantifying myocardial blood flow and the impact of different imaging parameters
on quantification. Perfusion CMR not only identifies the presence of microvascular obstruction after a myocardial infarction
but also relates it to patient prognosis. The ability to absolutely quantify myocardial blood flow improves the detection
and evaluation of epicardial coronary disease and its risk factors. CMR perfusion imaging has proved to be an invaluable tool
for understanding the integral role of the microcirculation in a variety of other cardiac disorders. Another advantage of
perfusion CMR is the ability to measure differences in subendocardial and subepicardial blood flow. Newer techniques such
as ASL and BOLD imaging promise to further improve the ability of CMR to assess the microcirculation without the use of exogenous
contrast agents. 相似文献
998.
Higashiura W Sakaguchi S Morimoto K Kichikawa K 《Cardiovascular and interventional radiology》2008,31(5):1013-1017
We present a case of fracture of a single self-expanding stent placed in the common iliac artery (CIA). An 80-year-old woman
underwent placement of a self-expanding stent for CIA occlusion. Stent fracture and reocclusion were detected after 18 months.
Successful revascularization was achieved using a stent-in-stent maneuver. The possibility of stent fracture with reocclusion
should be considered following treatment with a single self-expanding stent for CIA occlusion. 相似文献
999.
Morimoto K Sakaguchi H Tanaka T Yamamoto K Anai H Hayashi T Satake M Kichikawa K 《Cardiovascular and interventional radiology》2008,31(5):981-985
The purpose of this study was to investigate the pharmacological advantages of transarterial chemoembolization (TACE) with
cisplatin powder for hypervascular hepatic tumors in animal experiments. VX2 tumors were transplanted to the livers of nine
rabbits. Cisplatin (1 mg/kg) was infused into the proper hepatic artery. In the cisplatin-HAI group, cisplatin solution was
infused. In the cisplatin-GS-TACE group, after infusion of cisplatin solution, gelatin sponge particles were used for embolization.
In the cisplatin-Lp-TACE group, after infusion of a cisplatin powder and lipiodol (10 mg/ml) suspension, gelatin sponge particles
were used for embolization. Before and after administration, platinum concentrations in plasma were measured. Using liver
specimens that were excised 60 min after infusion, platinum concentrations in tumorous and nontumorous liver tissues were
measured. The mean platinum concentration in tumorous tissue was 0.88 μg/ml for the cisplatin-HAI group, 1.23 μg/ml for the
cisplatin-GS-TACE group, and 12.65 μg/ml for the cisplatin-Lp-TACE group. The platinum concentration for the cisplatin-Lp-TACE
group was significantly higher than that for the cisplatin-HAI group (p = 0.004) and the cisplatin-GS-TAE group (p = 0.004). The mean platinum concentration in nontumorous liver tissue was 0.98 μg/ml for the cisplatin-HAI group, 1.13 μg/ml
for the cisplatin-GS-TACE group, and 1.09 μg/ml for the cisplatin-Lp-TACE group; no significant differences were seen. At
both 5 and 10 min after infusion, the platinum concentrations for the cisplatin-Lp-TACE group were lower than those for the
other two groups. The present results suggest that TACE using cisplatin powder/lipiodol suspension and gelatin sponge for
hypervascular hepatic tumors has a number of pharmacological advantages.
This material was presented at 2007 CIRSE. 相似文献
1000.
Popliteal venous aneurysm is a rare cause of recurrent pulmonary embolism, although the true incidence of aneurysm is probably
underestimated. One-third of patients suffer further embolic events despite therapeutic anticoagulation. We report the case
of a 59-year-old male who presented with recurrent PEs over a period of 12 years despite anticoagulation therapy. A thrombophilia
screen and abdominal ultrasound were normal at that time. He reattended with recurrent pulmonary emboli, left calf swelling,
and a mass in his left popliteal fossa causing limitation of knee movement. Venous duplex and MRI of his popliteal fossa demonstrated
a thrombosed true popliteal venous aneurysm with popliteal and superficial femoral vein occlusion. In view of the mass effect
we proceeded to surgical excision of his aneurysm after prophylactic placement of an IVC filter. The patient regained normal
knee function with intensive inpatient physiotherapy. He has been recommenced on lifelong anticoagulant. The presentation,
investigation, and management of the condition are briefly discussed. We suggest that a bilateral lower limb duplex is performed
to exclude venous aneurysm in all patients presenting with pulmonary embolism in which an underlying source cannot otherwise
be identified and no thrombophilic tendency is detected. 相似文献