全文获取类型
收费全文 | 337篇 |
免费 | 9篇 |
国内免费 | 12篇 |
专业分类
儿科学 | 13篇 |
妇产科学 | 4篇 |
基础医学 | 25篇 |
口腔科学 | 5篇 |
临床医学 | 26篇 |
内科学 | 74篇 |
皮肤病学 | 20篇 |
神经病学 | 2篇 |
特种医学 | 155篇 |
外科学 | 6篇 |
综合类 | 3篇 |
预防医学 | 10篇 |
药学 | 6篇 |
中国医学 | 1篇 |
肿瘤学 | 8篇 |
出版年
2023年 | 1篇 |
2021年 | 1篇 |
2020年 | 4篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 4篇 |
2007年 | 13篇 |
2006年 | 3篇 |
2005年 | 1篇 |
2004年 | 3篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 13篇 |
1997年 | 22篇 |
1996年 | 24篇 |
1995年 | 15篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 22篇 |
1988年 | 13篇 |
1987年 | 18篇 |
1986年 | 17篇 |
1985年 | 20篇 |
1984年 | 13篇 |
1983年 | 7篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 6篇 |
排序方式: 共有358条查询结果,搜索用时 15 毫秒
111.
We describe the chromosomal abnormalities found in 104 previously untreated patients with non-Hodgkin's lymphoma (NHL) and the correlations of these abnormalities with disease characteristics. The cytogenetic method used was a 24- to 48-hour culture, followed by G- banding. Several significant associations were discovered. A trisomy 3 was correlated with high-grade NHL. In the patients with an immunoblastic NHL, an abnormal chromosome no. 3 or 6 was found significantly more frequently. As previously described, a t(14;18) was significantly correlated with a follicular growth pattern. Abnormalities on chromosome no. 17 were correlated with a diffuse histology and a shorter survival. A shorter survival was also correlated with a +5, +6, +18, all abnormalities on chromosome no. 5, or involvement of breakpoint 14q11-12. In a multivariate analysis, these chromosomal abnormalities appeared to be independent prognostic factors and correlated with survival more strongly than any traditional prognostic variable. Patients with a t(11;14)(q13;q32) had an elevated lactate dehydrogenase (LDH). Skin infiltration was correlated with abnormalities on 2p. Abnormalities involving breakpoints 6q11-16 were correlated with B symptoms. Patients with abnormalities involving breakpoints 3q21-25 and 13q21-24 had more frequent bulky disease. The correlations of certain clinical findings with specific chromosomal abnormalities might help unveil the pathogenetic mechanisms of NHL and tailor treatment regimens. 相似文献
112.
TB Chu CW Liao YC Huang YT Chang ASRJ Costa DD Ji T Nara A Tsubouchi Peter WS Chang WT Chiu CK Fan 《Iranian Journal of Parasitology》2012,7(1):67-72
Background
A parasitological survey of Schistosoma haematobium and S. intercalatum infection among primary schoolchildren in capital area of Democratic Republic of São Tomé and Príncipe (DRSTP) was undertaken.Methods
Subjects with positive infection were confirmed by the detection of S. haematobium ova in the urine or S. intercalatum ova in the stool by using centrifugation concentration or merthiolate-iodine-formalin concentration method. Totally, 252 urine and stool samples, respectively, were obtained from apparently healthy schoolchildren, of which 121 from boys (9.8 ± 1.4 yr) and 131 from girls (9.7 ± 1.3 yr).Results
None of participating schoolchildren were found having S. haematobium ova in the urinary specimen. While, among 4 primary schools studied, only schoolchildren from Saint Marçal were detected with S. intercalatum ova in the fecal specimen, making the overall prevalence of S. intercalatum infection among schoolchildren was 2.4% (6/252) and girls had insignificantly higher prevalence (3.1%, 4/131) than that (1.7%, 2/121) in boys (χ2 = 0.5, P = 0.5).Conclusion
Water control and sanitation as well as snails eliminated by molluscicides are urgently needed to reduce S. intercalatum infection in DRSTP inhabitants. 相似文献113.
Hubertus M.A. Andree Gerard T. Barkema Wim Lourens Arie Taal Jos C. Vermeulen 《Neural networks》1993,6(6):785-790
A comparison study was carried out between feedforward neural networks composed of binary linear threshold units and digital circuits. These networks were generated by the regular partitioning algorithm and a modified Quine-McCluskey algorithm, respectively. The size of both types of networks and their generalisation properties are compared as a function of the nearest-neighbour correlation in the binary input sets. The ratio of the number of components required by digital circuits and the number of neurons grows linearly for the input sets considered. The considered neural networks do not outperform digital circuits with respect to generalisation. Sensitivity analysis leads to a preference for digital circuits, especially for increasing number of inputs. In the case of analog input sets, hybrid networks of binary neurons and logic gates are of interest. 相似文献
114.
New bone formation in the peripheral skeleton was detected radiographically in 67% (22/33) of patients studied for new periarticular pain among 72 patients with osteoporosis being treated with fluoride, 66-88 mg/d, for 6 or more months. Changes included periosteal and endosteal new bone formation as well as trabecular thickening and were localized in areas of high mechanical stress. Sufficient mineral deposition for radiographic detection required 6 or more months of fluoride treatment. Radiologists must differentiate fluoride-induced new bone formation from other-processes, such as fractures and tumor, and elicit information on fluoride intake in suspicious cases. 相似文献
115.
Using a 0.35-T superconducting magnet and spin echo imaging, we prospectively evaluated 11 patients who had proved hepatic cavernous hemangioma. Magnetic resonance (MR) identified more lesions than either contrast-enhanced CT, or ultrasonography. The MR appearance was consistent; hemangiomas were homogeneous and generally isointense at short TR and TE intervals but were hyperintense at long TR intervals and greatly hyperintense at long TR and long TE intervals. However, the MR appearance of hemangioma was not specific; 2/14 other focal hepatic masses had similar features. The calculated relaxation times (T1, T2) were not useful in lesion characterization, although the intensity ratio of hemangioma to normal liver at the TR = 2.0 sec TE = 56 msec pulse sequence was useful in diagnosis since hemangiomas always had a ratio greater than 1.4. 相似文献
116.
Obstetrical magnetic resonance imaging: fetal anatomy 总被引:8,自引:1,他引:7
McCarthy SM; Filly RA; Stark DD; Hricak H; Brant-Zawadzki MN; Callen PW; Higgins CB 《Radiology》1985,154(2):427-432
Nine patients who were 34-36 weeks pregnant underwent magnetic resonance (MR) imaging. Sagittal images using spin echo technique (TR 2.0 sec, TE 28 msec) were optimal for delineating fetal anatomy. The fetal cardiovascular, pulmonary, and central nervous systems were depicted in all cases. The heart and major vessels were readily seen due to the natural contrast of flowing blood. The intensity of the fluid-filled lungs greatly increased with a longer TR or TE, delimiting thorax from liver. The brain was relatively featureless due to the lack of gray-white matter differentiation. The umbilical cord within the amniotic fluid and its insertion into the placenta and fetus was identified in all cases. MR is a new modality for fetal imaging that offers tissue-characterization information that complements the superior anatomic detail of ultrasound scanning. 相似文献
117.
Superparamagnetic iron oxide: clinical application as a contrast agent for MR imaging of the liver 总被引:32,自引:0,他引:32
Stark DD; Weissleder R; Elizondo G; Hahn PF; Saini S; Todd LE; Wittenberg J; Ferrucci JT 《Radiology》1988,168(2):297-301
Superparamagnetic iron oxide (ferrite) particles were evaluated as a contrast agent for magnetic resonance (MR) imaging. In this pilot study, doses ranging from 10 to 50 mumol/kg were administered intravenously to 15 patients. Ferrite-enhanced images of the liver obtained with standard pulse sequence techniques significantly increased the number of hepatic lesions detected (P less than .01) and reduced the threshold size for detection to 3 mm (P less than .01). The improved clinical performance of ferrite-enhanced images correlated with significant increases in measured contrast-to-noise ratios (P less than .01). Degradation of superparamagnetic activity and/or clearance of ferrite from the liver was demonstrated as early as 12 hours after injection, suggesting that the lack of chronic toxicity observed in animal studies may be reproduced in humans. These initial clinical results appear to confirm extensive preclinical data indicating that ferrite administered at a dose of 20 mumol/kg has the potential to significantly improve the performance of abdominal MR imaging. 相似文献
118.
119.
120.
Clip placement after stereotactic vacuum-assisted breast biopsy 总被引:3,自引:0,他引:3