全文获取类型
收费全文 | 13069篇 |
免费 | 953篇 |
国内免费 | 238篇 |
专业分类
耳鼻咽喉 | 51篇 |
儿科学 | 370篇 |
妇产科学 | 416篇 |
基础医学 | 601篇 |
口腔科学 | 93篇 |
临床医学 | 4541篇 |
内科学 | 1274篇 |
皮肤病学 | 57篇 |
神经病学 | 228篇 |
特种医学 | 1659篇 |
外科学 | 1406篇 |
综合类 | 1920篇 |
现状与发展 | 1篇 |
预防医学 | 471篇 |
眼科学 | 127篇 |
药学 | 576篇 |
8篇 | |
中国医学 | 93篇 |
肿瘤学 | 368篇 |
出版年
2024年 | 32篇 |
2023年 | 232篇 |
2022年 | 481篇 |
2021年 | 635篇 |
2020年 | 641篇 |
2019年 | 621篇 |
2018年 | 617篇 |
2017年 | 616篇 |
2016年 | 419篇 |
2015年 | 489篇 |
2014年 | 1007篇 |
2013年 | 829篇 |
2012年 | 761篇 |
2011年 | 738篇 |
2010年 | 616篇 |
2009年 | 611篇 |
2008年 | 600篇 |
2007年 | 527篇 |
2006年 | 553篇 |
2005年 | 408篇 |
2004年 | 345篇 |
2003年 | 276篇 |
2002年 | 185篇 |
2001年 | 197篇 |
2000年 | 179篇 |
1999年 | 158篇 |
1998年 | 128篇 |
1997年 | 133篇 |
1996年 | 105篇 |
1995年 | 96篇 |
1994年 | 90篇 |
1993年 | 56篇 |
1992年 | 66篇 |
1991年 | 57篇 |
1990年 | 39篇 |
1989年 | 48篇 |
1988年 | 43篇 |
1987年 | 43篇 |
1986年 | 60篇 |
1985年 | 53篇 |
1984年 | 36篇 |
1983年 | 45篇 |
1982年 | 70篇 |
1981年 | 62篇 |
1980年 | 33篇 |
1979年 | 36篇 |
1978年 | 64篇 |
1977年 | 25篇 |
1976年 | 41篇 |
1975年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
M. Amgwerd M. Röthlin D. Candinas R. Schimmer H. P. Klotz F. Largiadèr 《Langenbeck's archives of surgery / Deutsche Gesellschaft fur Chirurgie》1994,379(6):335-340
A number of studies have shown that ultrasound has an advantage over physical examination in the diagnosis of acute appendicitis. Most of these studies were conducted by experts in the field of ultrasonography. In this study the influence of experience on the results of the sonography of actue appendicitis were evaluated. All 203 patients admitted to our unit between December 1990 and December 1992 were examined physically and sonographically by a team of surgeons consisting of one experienced sonographer and six inexperienced surgical trainees. Laparotomy was performed in 136 patients (46%). Appendicitis was demonstrated histologically in 119 cases (39.4%). Initial clinical findings were positive in 87 (28.8%). Sonography was positive in 119 patients (39.4%). The 163 patients not operated on demonstrated other pathology on ultrasound in 60 cases (19.9%). The rate of negative laparotomies amounted to 7.2% in our study. Sensitivity and specificity for the sonographic diagnosis were 92% and 95%, respectively. They were only 81% and 80% for physical examination. Overall accuracy was 92% for sonography. Sensitivity and specificity for the inexperienced surgeons were 87% and 93%, respectively, while the experienced surgeon reached values of 97% and 98%, respectively. The results of both groups are comparable with values in the literature, suggesting that ultrasound evaluation of appendicitis is not a diagnostic tool limited to a few experienced sonographers. 相似文献
62.
Ultrasonography in the detection of cervical incompetency 总被引:2,自引:0,他引:2
Mario Podobnik Milan Buli Nikola Smiljanic Josip Bistri
ki 《Journal of clinical ultrasound : JCU》1988,16(6):383-391
In 80 pregnancies with clinical and ultrasonic signs of cervical incompetency, the length of the cervix and the thickness of the anterior wall of a lower uterine segment have been evaluated ultrasonically. We have also measured the width of the endocervical canal and studied the prolapse of fetal membranes (with fetal parts) into the endocervical canal. We evaluated these same parameters in 80 healthy pregnancies. The length of the cervix, the thickness of the anterior wall of a lower uterine segment, and the width of the endocervical canal were followed longitudinally in the patients from the 10th to the 36th gestation week. No statistically significant differences between age groups were found. In four age groups at risk for cervical incompetency, cervical lengths and wall thickness were significantly different (p less than 0.001) from those in comparable controls. Forty-five percent of the patients in the at-risk group, with cervical cerclage, delivered at 37.3 (range: 32 to 41) weeks and 6.25% of pregnancies ended in abortion when the amniotic membrane herniated into the cervical canal, with or without some part of the fetus. 相似文献
63.
目的:探讨B超对异位妊娠的诊断价值。方法:对2004年1月~2009年1月的86例异位妊娠患者,采用超声诊断仪进行检查、分析。结果:超声检查的86例异位妊娠患者,诊断符合84例,确诊率为97.6%,误诊2例,误诊率为2.4%。结论:超声检查有着无创性、可重复性等不可比拟的优越性,为异位妊娠患者的诊断及治疗提供了可靠的依据。 相似文献
64.
目的 :探讨超声引导下细针穿刺抽吸活检诊断胸壁结核的方法和使用价值。方法 :对 2 5例患有胸壁结核患者 ,在 B超引导下经皮胸壁细针穿刺抽吸活检 ,同时与超声图像诊断进行比较。结果 :超声引导下细针穿刺抽吸活检诊断正确者 2 3例 (92 .0 0 % ) ,不正确者仅 2例 (8.0 0 % ) ;超声图像诊断正确者 11例 (44 .0 0 % )。结论 :超声引导下细针穿刺抽吸活检诊断早期、不典型的胸壁结核 ,具有诊断正确率高 ,诊断迅速等特点。 相似文献
65.
高血压病血管内皮功能障碍及治疗 总被引:15,自引:0,他引:15
内皮细胞功能障碍是近年来的热门研究课题,从基础到临床受到广泛重视。高血压是发病率最高的心血管疾病,其发病环节与内皮细胞功能关系密切,二者均是心脑血管事件链中的重要环节。本文回顾了多种内皮因子的功能及其与高血压的关系,高血压病内皮功能障碍的可能机制,肱动脉超声检查方法以及内皮功能障碍的治疗对策。 相似文献
66.
目的设计超声引导下臂丛神经阻滞时的穿刺针导引器,并在体外和临床上验证其效果。方法自制一个穿刺针导引器,其主要部分是一个双层的扇形不锈钢薄片。选择80例在臂丛神经阻滞下行上肢手术的患者,随机分为自由手组和导引组,每组40人。由四位麻醉医师实施在超声引导下臂丛神经阻滞(锁骨上入路),每位医师完成20例,10例用自由手技术,10例用穿刺针导引器引导技术。记录穿刺针的主观可视性、阻滞完成时间、临床效果以及麻醉医师和患者对臂丛神经阻滞的满意度。结果导引组的针的主观可视性显著优于自由手组(P<0.05);导引组的阻滞完成时间明显短于自由手组(P<0.01);麻醉医师使用导引技术的满意度高于使用自由手技术(P<0.05)。结论使用穿刺针引导技术更容易完成超声引导下臂丛神经阻滞。 相似文献
67.
原发性胆囊癌的影像学诊断(附52例分析) 总被引:3,自引:0,他引:3
目的:探讨超声、CT和MRI在胆囊癌诊断中的临床应用价值。方法:回顾性分析52例经手术及病理证实的胆囊癌的超声、CT和MRI资料。结果:52例胆囊癌术前超声诊断符合率为73.1%(38/52),CT诊断符合率为75%(39/52),MRI符合率为83.3%(15/18)。其中合并慢性胆囊炎伴胆囊结石21例(40.4%)。影像表现为4种类型:胆囊壁增厚型(16例),乳头结节型(15例),混合型(壁厚和结节8例),实体型(13例)。结论:超声、CT和MRI对胆囊癌的诊断具有重要的临床价值,合理的应用能更好地指导临床治疗和术后疗效观察。 相似文献
68.
目的 探讨B超引导下经皮肝穿刺肝静脉成形术在布-加综合征的介入治疗中的应用价值和疗效。方法 对7例下腔静脉狭窄同时合并肝静脉狭窄或闭塞的布-加综合征患者,在施行下腔静脉成形术后,采用B超引导下经皮肝静脉穿刺的方法,实施肝静脉球囊扩张术或支架植入术。结果 7例患者在单独实施下腔静脉成形术效果不显著的情况下,在B超引导下实施肝静脉成形术,2例单纯球囊扩张,5例植入支架,无严重并发症,术后腹水、下肢水肿等症状有不同程度改善。结论 B超引导下的经皮肝静脉穿刺肝静脉成形术,定位准确,实施快捷,对合并肝静脉狭窄或梗阻的布-加综合征患者症状的缓解有明显效果。 相似文献
69.
G. M. Howard T. V. Nguyen N. A. Pocock P. J. Kelly J. A. Eisman 《Osteoporosis international》1997,7(3):190-194
Calcaneal ultrasound has been increasingly studied for its potential in the assessment of osteoporotic fracture risk. The accuracy of such an assessment is, in part, dependent on the reproducibility of the measurement. This study examines the impact of handedness on ultrasound measurements [broadband ultrasound attenuation (BUA) and velocity of sound (VOS)] in the calcaneus. Two hundred and sixty-four subjects (57 men and 297 women) aged 51.1+13.6 years (mean ± SD) were studied. For each subject, calcaneal ultrasound measurements were performed on both heels with a McCue CUBA ultrasound densitometer. Right-handed dominance (94.7%) was determined by structured interview. In men, BUA measurements were significantly higher on the dominant side: mean difference 4.1±1.5 dB/MHz (mean ± SD;p=0.009), equivalent to 4.2+1.5% and more than 4 times the average rate of annual change in BUA. The difference between sides was greater in young (<50 years) than old men (>50 years). Among the women, the difference was not statistically significant (0.7±0.9 dB/MHz;p=0.4); however, it was significant in younger women (20–30 years) (99±4 vs 90±4 dB/MHz,p=0.01). By contrast VOS did not differ between sides in either men or women irrespective of age. Within-subject standard deviation of BUA was 9.8 dB/MHz for men and 8.6 dB/ MHz for women and the component due to right and left difference was 8.4 dB/MHz for men and 6.9 dB/MHz for women. This variability of BUA between right and left heels could increase the false-positive rate by up to 28% for a cut-off of 2 SD below the mean. These data indicate that variation between left and right heel measurements of BUA is higher than that of random error measurements, particularly in men and younger, presumably more physically active subjects. Although VOS measurements were not side dependent, in the smaller number of studies examining VOS and fracture risk, VOS appears to have a weaker predictive power than BUA. Clinical and epidemiological studies involving calcaneal BUA measurements should standardize the side measured to either the dominant or non-dominant heel, to reduce within-subject variation and increase their power. 相似文献
70.
Between 1980 and 1993, 680 patients with non-Hodgkin's lymphomas (NHL) and Hodgkin's disese (HD) were studied by ultrasonography. In 210 patients a total of 254 extranodular abdominal lymphoma inflitrates were diagnosed. Infiltrates were confirmed histologically in 118 patients and through the clinical course and follow-up studies in 92 patients. Lymphoma infiltrates were seen most frequently in the spleen (N = 101), the gastrointestinal tract (n=70), the liver (n = 47), the kidneys (n = 17) and other organs (n = 19). The sonographic features of lymphomatous infiltrates in different extranodal sites are described, and possible correlations between lymphoma subtypes and sonographic texture characteristics are investigated. Different infiltration patterns of lymphoma subtypes could be indentical in liver and spleen. High-grade NHLs most frequently showed large-nodular lesions, whereas low-grade NHLs and HD showed a tendency towards small-nodular or diffuse lesions. The role of ultrasonography in the clinical management of lymphoma pateins is discussed.Correspondece to: C. Görg 相似文献