全文获取类型
收费全文 | 963篇 |
免费 | 81篇 |
国内免费 | 35篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 71篇 |
妇产科学 | 3篇 |
基础医学 | 188篇 |
口腔科学 | 29篇 |
临床医学 | 109篇 |
内科学 | 178篇 |
皮肤病学 | 24篇 |
神经病学 | 40篇 |
特种医学 | 186篇 |
外科学 | 45篇 |
综合类 | 25篇 |
预防医学 | 42篇 |
眼科学 | 15篇 |
药学 | 82篇 |
中国医学 | 1篇 |
肿瘤学 | 34篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 15篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 26篇 |
2017年 | 21篇 |
2016年 | 22篇 |
2015年 | 33篇 |
2014年 | 18篇 |
2013年 | 34篇 |
2012年 | 30篇 |
2011年 | 22篇 |
2010年 | 48篇 |
2009年 | 49篇 |
2008年 | 21篇 |
2007年 | 29篇 |
2006年 | 36篇 |
2005年 | 43篇 |
2004年 | 20篇 |
2003年 | 3篇 |
2002年 | 17篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 18篇 |
1998年 | 49篇 |
1997年 | 50篇 |
1996年 | 51篇 |
1995年 | 34篇 |
1994年 | 41篇 |
1993年 | 36篇 |
1992年 | 12篇 |
1991年 | 18篇 |
1990年 | 9篇 |
1989年 | 24篇 |
1988年 | 45篇 |
1987年 | 22篇 |
1986年 | 18篇 |
1985年 | 29篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 14篇 |
1975年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有1079条查询结果,搜索用时 15 毫秒
61.
Nikola Y. Kolev Anton Y. Tonev Valentin L. Ignatov Aleksander K. Zlatarov Vasil M. Bojkov Tanya D. Kirilova Elitsa Encheva Krasimir Ivanov 《International surgery》2014,99(2):106-111
In the last 20 years, endorectal ultrasound (ERUS) has been one of the main diagnostic methods for locoregional staging of rectal cancer. ERUS is accurate modality for evaluating local invasion of rectal carcinoma into the rectal wall layers (T category). Adding the three-dimensional modality (3-D) increases the capabilities of this diagnostic tool in rectal cancer patients. We review the literature and report our experience in preoperative 3-D ERUS in rectal cancer staging. In the group of 71 patients, the staging of preoperative 3-D endorectal ultrasonography was compared with the postoperative morphologic examination. Three-dimensional ERUS preoperative staging was confirmed with morphologic evaluation in 66 out of 71 cases (92.9%). The detection sensitivities of rectal cancer with 3-D ERUS were as follows: T1, 92.8%; T2, 93.1%; T3, 91.6%; and T4, 100.0%; with specificity values of T1, 98.2%; T2, 95.4%; T3, 97.8%; and T4, 98.5%. Three-dimensional ERUS correctly categorized patients with T1, 97.1%; T2, 94.3%; T3, 95.7%; and T4, 98.5%. The percentage of total overstaged cases was 2.75% and that of understaged cases was 6.87%. The metastatic status of the lymph nodes was determined with a sensitivity of 79.1% (19 of 24), specificity of 91.4% (43 of 47), and diagnostic accuracy of 87.3% (62 of 71). In our experience, 3-D ERUS has the potential to become the diagnostic modality of choice for the preoperative staging of rectal cancer.Key words: Three-dimensional endorectal ultrasound, Rectal cancerEndorectal ultrasound (ERUS) has been used as a diagnostic tool for evaluation and staging of rectal cancer since the 1980s.1 According to the literature, in studies with more than 50 patients included, an overall accuracy of approximately 81.8% was reported.2 Most of the studies present data between 85% and 95%, but in the studies with more than 200 patients, the accuracy rates are relatively lower—63.3% and 69%, respectively.3,4 A common disadvantage of ERUS and magnetic resonance imaging (MRI) is the overstaging of T2 tumors owing to an irregular outer rectal wall resulting from transmural tumor extension or inflammation around the tumor. Another challenge for the ERUS, and especially the rigid probes, are the locally advanced, stenotic tumors, where the probe may not be able to pass above the lesion.5 The nodal staging accuracy of ERUS ranges from 70% to 75%.1,5,6 The metastatic lymph nodes are distinguished by hypoechoic appearance, round shape, peritumoral location, and size >5 mm.7,8 Lymph nodes >5 mm have a 50% to 70% chance of being malignant, while those <4 mm have only a 20% chance.9,10 A new modality of endorectal ultrasound represents a three-dimensional (3-D) ERUS that provides better visual images of the tumor volume and spatial relations to the adjacent organs and structures, even better than those of MRI, which leads to better diagnostic accuracy than MRI and standard ERUS.11–15 The unique 3-D–ERUS longitudinal scan can precisely assess the tumor size and location.16 The most important feature of this upgraded modality is the ability to reduce interpreter errors and offer potential predictive value. Three-dimensional ERUS provides the possibility to distinguish blood vessels from lymph nodes and allow precise fine needle aspiration (FNA) biopsies.13,17 The infiltration of circumferential margin has been proven to correlate with T category, lymph node metastasis histologic tumor differentiation, and lymphovascular invasion.13,17 Three-dimensional ERUS gives the possibility of multiplane evaluation of the tumor, allowing visualization of more subtle changes in the tumor characteristics and therefore better T and N categorizing.18 A review of 86 patients who underwent standard 3-D ERUS, ERUS and 4-channel detector computed tomography (CT) demonstrated T-category accuracy of 78%, 69%, and 57%, respectively.19 After analysis of the examiner''s error, the accuracy of 3-D ERUS for T category has reached 91% for 3-D ERUS and 88% for standard ERUS, and the N category accuracy improved to 90% and 76%, respectively. Also, ERUS can be used for diagnosis of premalignant lesions such as adenomas and polyps.20 The main goal is to properly identify any chance of tumor invasion in the primary lesion and involvement of the surrounding lymph nodes in case the absence of those alarming characteristics allows for endoscopic resection of the lesion. Using higher-resolution probes, ERUS can distinguish T0 from T1 lesions. According to a meta-analysis of 258 biopsy-negative tumors, ERUS identified tumor mass in 81% of the 24 lesions, which were found to be invasive tumors on morphologic examination.20 Another series of 60 patients with pT0/pT1 lesions demonstrated sensitivity and specificity of ERUS 89% and 88%, respectively.21 As with MRI, 3-D ERUS could provide an evaluation of the mesorectal fascia.14,22The reported data lead to the position that 3-D ERUS combines the high-resolution images of the rectal wall and cost-effectiveness of standard ERUS with the multiplanar and stereoscopic imaging capabilities of MRI. Three-dimensional ERUS may be the future premier imaging modality used in rectal cancer management. 相似文献
62.
Muzyko E. A. Tkacheva G. A. Perfilova V. N. Matvienko L. S. Naumenko L. V. Vasil’eva O. S. Tyurenkov I. N. 《Bulletin of experimental biology and medicine》2020,168(4):457-464
Bulletin of Experimental Biology and Medicine - We studied the effects of GABA derivatives on anxious and compulsive behavior of progeny of rats with experimental preeclampsia provoked by... 相似文献
63.
64.
65.
66.
保证输血时血清学方面的安全,首要的是对受血者与献血者ABO血型定型,血清学检查通常分两个步骤.正定型通常使用鼠源单克隆抗体检测红细胞表面是否存在A或B抗原.互补的实验即反定型,利用当红细胞上缺乏A或B抗原时,人群可天然产生相对应的抗体的原理,检测血清中是否存在抗-A或者抗-B抗体.确定了受血者红细胞表面的ABO抗原以及血浆中的抗体,便能确定血型,为其提供相合的血液. 相似文献
67.
Abstract: The study of plasma integrates physics, chemistry, biology, and engineering, and has recently engaged medicine and dental hygiene in research efforts. The study of plasma holds promise for a myriad of applications ranging from lasers and electronics, hazardous waste management, decontamination, sterilization and disinfection of foods, soil, water, instruments, to medical uses in wound healing and treating certain types of tumours and cancers. Plasma represents a new state-of-the-art sterilization and disinfection treatment for certain oral and enviornmental pathogens, heat-sensitive materials, contaminated medical waste, hard and soft surfaces, and ventilation systems may assist health care facilities in the management of various health concerns. The role that Low Temperature Atmospheric Pressure Plasma (LTAPP) could play in the inactivation of pathogenic microorganisms might prove to be a new, faster, noncorrosive, more economical alternative, as well as support green healthcare. 相似文献
68.
Objective To explore the characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC). Methods Seven patients with arrhythmogenic right ventricular cardiomyopathy and 34 members of three families were studied. All patients and family members underwent history collection, clinical examination, electrocardiogram (ECG), two-dimensional echocardiography (2-DE) and a signal averaging electrocardiogram. Programmed ventricular stimulation was performed in five patients. Results All patients and family members had normal morphologic characteristics and normal function of the left ventricular by 2-DE. Fourteen persons had abnormal findings indicating ARVC. Five had enlargement of the right ventricular with diffused hypocontractility, eight had thin and systolic bulging in the focal anterior wall with hypokinesia and one had bulging of the inferior wall. Twenty-five persons (seven patients and 18 family members) had abnormal findings in ECG. Positive ventricular late potential was recorded in 13 persons (six patients). Two to three monomorphic ventricular tachycardia (VT) with left bundle branch block (LBBB) configurations were induced in five patients. Ventricular fibrillation was induced in two patients during the electrophysiologic study (EPS). Five patients had very high pacing threshold and/or ineffective pacing in one or many regions of the right ventricle. Two members of one family died suddenly. One member was a dwarf with ARVC. Spontaneous VT with a left bundle branch block (LBBB) configuration was recorded in five patients, polymorphic VT with extremely short coupling interval in one, and premature ventricular complexes with LBBB configuration in 12 (six patients). Conclusion Our familial study strongly suggests that ARVC may be a hereditary disease and it is helpful in the diagnosis and detection of ARVC. The most common manifestations were abnormal structure and function of the right ventricle and abnormal ECG of repolarization and ventricular arrhythmia which originates from the right ventricle. 相似文献
69.
70.
Rapid decrease in tuberculin skin test reactivity at preschool age after newborn vaccination 总被引:2,自引:0,他引:2
L Kröger ML Katila M Korppi E Brander M Pietikäinen 《Acta paediatrica (Oslo, Norway : 1992)》1992,81(9):678-681
A study of tuberculin sensitivity was performed in 353 children aged 4-6 years, all vaccinated at birth with British BCG vaccine. Significant waning of tuberculin reactions with increasing age was found (p < 0.05). In the age group < 4.5 years, the mean tuberculin reaction was 6.6 mm, in the age group 4.5-5.5 years 5.2 mm and in the age group of > 5.5 years 3.5 mm. The number of children with positive reactions (> or = 5 mm) was 165 (40%) and those with strong reactions (> or = 10 mm) 49 (14%). None of the latter children had active tuberculosis during a follow-up period of 12 months. Eighty-three (24%) of the children had no reaction. The children who had been revaccinated with the MPR vaccine against measles, rubella and parotitis (n = 31) had significantly larger tuberculin reactions than the non-revaccinated children. Atopic dermatitis or infections during the preceding six months did not have any significant influence on reaction sizes. Our results demonstrate that the variation in size of tuberculin reactions after BCG vaccination at birth is large. We conclude that tuberculin sensitivity wanes rapidly by the age of 4.0-6.3 years. 相似文献