首页 | 官方网站   微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   189篇
  免费   7篇
  国内免费   11篇
医药卫生   207篇
  2021年   1篇
  2020年   2篇
  2019年   2篇
  2018年   2篇
  2016年   3篇
  2015年   6篇
  2014年   7篇
  2013年   3篇
  2012年   11篇
  2011年   7篇
  2010年   3篇
  2009年   10篇
  2008年   12篇
  2007年   18篇
  2006年   5篇
  2005年   11篇
  2004年   15篇
  2003年   10篇
  2002年   11篇
  2001年   13篇
  2000年   16篇
  1999年   11篇
  1998年   5篇
  1997年   3篇
  1996年   3篇
  1995年   5篇
  1994年   1篇
  1993年   2篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1988年   1篇
  1969年   1篇
排序方式: 共有207条查询结果,搜索用时 15 毫秒
51.
(Received for publication on Dec. 8, 1998; accepted on Sept. 17, 1999)  相似文献   
52.
Effects of protamine on vascular smooth muscle of rabbit mesenteric artery   总被引:13,自引:0,他引:13  
Systemic hypotension is commonly observed in association with protamine administration after cardiopulmonary bypass. However, little information is available concerning the action of protamine on vascular smooth muscle. Thus, we investigated the action of protamine on vascular tissues using tension recording and microelectrode methods. Protamine (5-500 micrograms/ml) inhibited contractions induced by norepinephrine (NE)- or elevated K+ in a concentration-dependent manner in both endothelium-intact and -denuded strips. Protamine inhibition of NE contractions was less profound after endothelial denudation, whereas protamine inhibition of K(+)-induced contractions was less affected by prior denudation. In endothelium-intact strips, the protamine-induced inhibition was significantly reduced by inhibitors of the endothelium-derived relaxing factor pathway, including oxyhemoglobin, methylene blue, or NG-nitro-L-arginine, whereas the contractile inhibition was enhanced by superoxide dismutase. In endothelium-denuded strips, protamine inhibited Ca(2+)-induced contraction evoked in Ca(2+)-free solution containing 100 mM K+ and inhibited the NE-induced contraction under the following conditions: 1) in Ca(2+)-free solution; 2) after nifedipine treatment; and 3) after depletion of stored Ca2+ by A23187 or ryanodine. In membrane-permeabilized strips, protamine did not modify Ca(2+)-induced contraction. Protamine (50-500 micrograms/ml) did not modify the membrane potential of either endothelium-intact or -denuded strips. Furthermore, protamine irreversibly impaired acetylcholine-induced endothelium-dependent relaxant response, implying a toxic effect of protamine on the endothelium. We conclude that protamine exerts its inhibition on vascular smooth muscles in both an endothelium-dependent and -independent manner; i.e., the endothelium-dependent component is mediated probably by endothelium-derived relaxing factor, and direct smooth muscle effects are due to the inhibition of both Ca(2+)-influx and the NE-induced Ca2+ release from intracellular stores.  相似文献   
53.
54.
We report a unique case of exacerbation of renal lymphangiomatosis during pregnancy which was managed percutaneously until delivery. Renal lymphangiomatosis is a very rare benign disorder that might cause abdominal pain and rarely hypertension and hematuria. Surgical treatment options may result in nephrectomy. Percutaneous drainage of symptomatic renal lymphangiomas should be viewed as an efficient therapeutic option particularly when surgery is contraindicated. Received: 28 December 1999 Revised: 22 May 2000 Accepted: 23 May 2000  相似文献   
55.
Multidetector CT is becoming an alternative method for the diagnosis of coronary artery anomalies. We present the multidetector coronary CT angiography findings from a patient with right coronary artery duplication. Two separate right coronary arteries originating from the right aortic sinus were observed. Their anatomical course was well depicted, and atherosclerosis was excluded based on the CT angiography findings.  相似文献   
56.
Conventional CT or MRI has low accuracy in assessing chest wall invasion in patients with peripheral lung cancer. For preoperative evaluation of chest wall invasion by peripheral lung cancer, respiratory dynamic (RD) MRI was carried out in 98 patients in whom conventional CT scan showed that the tumour was abutting the pleural surface, but there was no evidence of definite tumour invasion. We used 1.5-T MR equipment. RD MR images were acquired by snapshot fast field echo sequence (repetition time = 8, echo time = 3, flip angle = 100) and 25 consecutive images were taken while the patient took deep breaths. These images were evaluated in cine mode to assess tumour movement along the chest wall. Sixty-one patients underwent surgical resection of the tumour and RD MR findings were compared with those in pathological specimens. RD MR showed free tumour movement along the chest wall in 34 patients. At pathological examination, the RD MR findings were proved correct in all patients. Pathologically, 20 patients had chest wall invasion and their RD MR was positive (sensitivity 100%). There were seven false-positive results among the 41 patients without chest wall invasion (specificity 82.9%). RD MR may improve the accuracy of conventional CT scan or MRI in the prediction of chest wall invasion of lung cancer, especially in patients in whom the results of conventional CT scan or MRI appear equivocal in the presence of a peripheral mass abutting the chest wall surface without obvious chest wall invasion.  相似文献   
57.
58.
OBJECTIVE: To compare contrast-enhanced magnetic resonance (MR) cholangiography (CE-MRC) performed with gadobenate dimeglumine with T2-weighted MRC (T2-MRC) for visualization of the bile ducts in nondilated biliary systems. MATERIALS AND METHODS: Twenty consecutive patients who underwent MR imaging (MRI) of the liver and pancreas with nondilated intrahepatic ducts were included in this retrospective study. T2-weighted MRC was performed using a multislice, high-resolution fat-suppressed half-Fourier acquisition turbo spin-echo sequence. Contrast-enhanced MR cholangiography was performed using a fat-suppressed 3-dimensional fast low-angle shot sequence acquired 1 to 1.5 hour after intravenous administration of gadobenate dimeglumine. For image interpretation, the biliary system was divided into 8 segments. Two readers graded visualization of each segment on T2-MRC and CE-MRC using a 5-point scale (0, nonvisualization; 4, excellent visualization). Final opinion for each sequence was rendered by consensus. Superiority of visualization was assessed using the McNemar test and comparing adequately (visualization scores 3 and 4) and inadequately (visualization scores 0, 1, and 2) visualized segments of the ducts on both sequences. Interobserver variability was assessed with kappa statistics. RESULTS: Overall and segment-based evaluation revealed superior visualization of biliary segments with CE-MRC compared with T2-MRC. We also found a statistically significant difference between the 2 sequences for overall and for right hepatic duct and cystic channel visualization (P < 0.05). A high concordance between readers 1 and 2 both for T2-MRC and CE-MRC was achieved (85.8% and 89.4%, respectively). CONCLUSIONS: Gadobenate dimeglumine can be used as an alternative intrabiliary contrast agent for contrast-enhanced MR cholangiography in nondilated biliary systems in patients with normal excretory liver function tests.  相似文献   
59.
OBJECTIVE: To determine the interobserver and intraobserver variations in sonographic measurement of thyroid volume in children. DESIGN: Thyroid volumes of 30 healthy children were measured by three separate observers. Additionally each observer measured thyroid volumes of ten separate children three times. METHODS: The data were used to assess intraobserver and interobserver variations in measurement of thyroid volume. Interobserver and intraobserver variations in measuring each diameter of the thyroid gland were also determined. The effect of thyroid size on interobserver and intraobserver variations was analyzed. RESULTS: Intraobserver variation in measurement of thyroid volume was 8.4+/-6.7% (mean+/-s. d.). Interobserver variation was 13.3+/-8.2%. The widest interobserver variation was encountered in determining the craniocaudal diameter of the thyroid gland. No correlation was found between thyroid volume and interobserver variation (r=-0.12, P=0.27), whereas a slight but statistically significant correlation was found between thyroid volume and intraobserver variation (r=-0.26, P=0.012). CONCLUSION: Significant interobserver and intraobserver variation occurs in sonographic measurement of thyroid volume in children.  相似文献   
60.
Mediterranean spotted fever (MSF) is caused by a tick-borne pathogen, Rickettsia conorii subsp. conorii, belonging to the spotted fever group (SFG) rickettsiae. The aim of the present study was to evaluate the cases with confirmed diagnosis of MSF from 2003 to 2009 in the Trakya region of Turkey. Patients with high fever, maculopapular rash (involving the palms or soles) and/or a black inoculation eschar at the site of the tick bite (tache noire) were included in the study. Before doxycycline treatment, skin biopsy specimens, preferably from the eschar or from the maculopapular rash, were obtained for DNA extraction. Immunofluorescence assay (IFA) was performed to detect IgM and IgG antibodies against R. conorii in acute and convalescent sera. Afterwards, a standard PCR reaction using primers suitable for hybridisation within the conserved region of genes coding for outer membrane protein A (ompA) and citrate synthase (gltA) and DNA sequencing were performed. There were 128 patients with confirmed MSF diagnosis. Using IFA, seroconversion or a fourfold or greater rise in titre was observed in 97 (77%) patients, whereas a single high titre was demonstrated in 16 (12.7%) patients. According to PCR analysis, 77 (72.6%) of 106 biopsy samples showed positive results. Of these, 58 (73%) of 79 biopsy specimens were from the eschar and 19 (70%) of 27 specimens were from the maculopapular rash. No significant difference was found between the rate of positive skin biopsies taken from the eschar and the maculopapular rash. DNA sequence analysis was performed to all PCR-positive cases, and R. conorii conorii (type strain: Malish, ATCC VR-613) was detected in each of them. MSF is prevalent, but has been underdiagnosed and underreported so far in Turkey. It is a potentially severe and even fatal disease resembling viral haemorrhagic fevers that has to be included in the differential diagnosis of febrile illness associated with thrombocytopenia, even in the absence of an eschar or a tick bite. While IFA allows for retrospective diagnosis in MSF, advanced molecular techniques provide the rapid detection of rickettsia in all skin samples, including eschar and maculopapular rash.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号