全文获取类型
收费全文 | 989篇 |
免费 | 98篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 6篇 |
儿科学 | 75篇 |
妇产科学 | 32篇 |
基础医学 | 91篇 |
口腔科学 | 36篇 |
临床医学 | 166篇 |
内科学 | 210篇 |
皮肤病学 | 27篇 |
神经病学 | 47篇 |
特种医学 | 156篇 |
外科学 | 70篇 |
综合类 | 25篇 |
预防医学 | 63篇 |
眼科学 | 12篇 |
药学 | 56篇 |
1篇 | |
中国医学 | 9篇 |
肿瘤学 | 51篇 |
出版年
2023年 | 2篇 |
2021年 | 8篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 21篇 |
2017年 | 23篇 |
2016年 | 25篇 |
2015年 | 28篇 |
2014年 | 36篇 |
2013年 | 42篇 |
2012年 | 16篇 |
2011年 | 28篇 |
2010年 | 41篇 |
2009年 | 67篇 |
2008年 | 30篇 |
2007年 | 47篇 |
2006年 | 19篇 |
2005年 | 25篇 |
2004年 | 11篇 |
2003年 | 15篇 |
2002年 | 10篇 |
2001年 | 21篇 |
2000年 | 14篇 |
1999年 | 23篇 |
1998年 | 72篇 |
1997年 | 82篇 |
1996年 | 57篇 |
1995年 | 51篇 |
1994年 | 37篇 |
1993年 | 43篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 26篇 |
1988年 | 22篇 |
1987年 | 27篇 |
1986年 | 14篇 |
1985年 | 17篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 9篇 |
1978年 | 5篇 |
1977年 | 11篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1934年 | 1篇 |
1931年 | 1篇 |
1930年 | 1篇 |
排序方式: 共有1133条查询结果,搜索用时 15 毫秒
101.
Detection and quantification of chronic cerebrovascular disease: comparison of MR imaging, SPECT, and CT 总被引:1,自引:0,他引:1
Seiderer M; Krappel W; Moser E; Hahn D; Schmiedek P; Buell U; Kirsch CM; Lissner J 《Radiology》1989,170(2):545-548
Twenty patients with angiographically proved occlusion of the internal carotid artery (ICA) (19 unilateral, one bilateral) were studied with magnetic resonance (MR) imaging, iodine-123 iodoamphetamine (IMP) single photon emission computed tomography (SPECT), xenon-133 SPECT, and computed tomography (CT). All patients had a history of stroke or prolonged reversible ischemic neurologic deficit for more than 4 weeks. By regions of interest, T1, T2, regional cerebral blood flow (rCBF), and the number and size of the lesions were determined. The data were expressed as interhemispheric ratios (diseased/nondiseased). The highest ratios obtained were for MR imaging (T1, 2.60 +/- 0.42; T2, 1.61 +/- 0.22 [mean +/- standard deviation]) followed by Xe-133 SPECT (0.58 +/- 0.13) and IMP SPECT (0.56 +/- 0.13). Correlation coefficients for MR imaging (1/T1, 1/T2) and IMP SPECT were below .21. The lesion size was greatest on IMP SPECT images, intermediate on MR images, and least on CT scans. However, MR imaging was superior in detection of pathologic areas (detection rates: MR, 100%; IMP SPECT, 91%; CT, 79%). Relaxation times do not correlate with rCBF. 相似文献
102.
103.
Venous clots: evaluation with MR imaging 总被引:2,自引:0,他引:2
In vitro and in vivo studies were performed to determine the proton relaxation and imaging characteristics of static blood and acute and organized clot in canine jugular veins. In vivo, it was found that two inversion recovery sequences using a short inversion time (100 msec) demonstrated better differentiation of signal intensity of intravascular clot from surrounding soft tissues than did standard T1- and T2-weighted sequences. In vitro, quantitative measurements showed marked reduction of both T1 and T2 relaxation time of acute clot compared with stagnant blood. In addition, the T1 relaxation time, and to a lesser extent the T2 relaxation time, shortened as the clot aged, indicating a potential role for magnetic resonance imaging in determining the age of venous thrombi. 相似文献
104.
Williamson MR; Boyd CM; McGuire EL; Angtuaco T; Westbrook KC; Lang NP; Alston J; Broadwater JR; Navab F; Bersey ML 《Radiology》1986,159(1):272-273
The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding. 相似文献
105.
Patrícia De Souza Rossignoli Oduvaldo CM Pereira Agnaldo B Chies 《Clinical and experimental pharmacology & physiology》2010,37(3):368-374
1. Orchidectomy results in long‐term testosterone deprivation similar to that observed in male clinical pathologies, such as hypogonadism and age‐related reductions in plasma testosterone concentrations. Although the vascular effects of these sorts of hormone deprivations are known in arteries, they have not been studied to the same extent in veins. 2. The aim of the present study was to determine the effect of orchidectomy, with or without subsequent testosterone replacement (started 23 days after orchidectomy; 10 mg/kg, i.m., testosterone propionate once every 5 days for 3 weeks), on responses of rat isolated portal veins and vena cavae to exogenous phenylephrine (PE). Isolated vessels were mounted in an organ bath and concentration–response curves constructed to PE (10?10–10?4 mol/L), endothelin (ET; 10?10–10?5 mol/L) and KCl (10?2–1.2 × 10?1 mol/L; as a control). 3. Orchidectomy had no effect on contractile responses of either the portal vein or vena cava to KCl. However, orchidectomy enhanced the maximum response (Rmax) of the portal vein, but not the vena cava, to PE. Testosterone replacement had no effect on these responses. The effects of orchidectomy on the Rmax to PE in portal veins were not altered by the nitric oxide synthase inhibitor NG‐nitro‐l‐ arginine methyl ester (10?4 mol/L) alone or combined with 10?5 mol/L indomethacin (a non‐selective cyclo‐oxygenase inhibitor), but they were abolished following treatment of isolated vessels with the ETA and ETB receptor antagonists BQ‐123 and BQ‐788 (both at 10?6 mol/L). Orchidectomy did not alter portal vein responses to the application of exogenous ET. 4. The results of the present study indicate that orchidectomy‐induced decreases in plasma testosterone can increase the venoconstrictor effects of PE on the portal vein and that this effect involves activation of both ETA and ETB receptors by locally produced ET. 相似文献
106.
107.
108.
Wallerian degeneration in the corticospinal tract was demonstrated by magnetic resonance (MR) imaging in a patient with Schilder disease. The histochemical stages of myelin breakdown that allow its demonstration by MR imaging are reviewed. 相似文献
109.
110.
��ǻ������θ��·�����Ƶ����Է��ֲ�2������ 总被引:7,自引:0,他引:7
目的 报告成功实施腹腔镜迷你胃旁路术治疗单纯性肥胖并2型糖尿病病人1例。方法 第二军医大学附属长海医院微创外科于2007年11月对1例伴有2型糖尿病的单纯性肥胖症病人行腹腔镜迷你胃旁路术。结果 病人手术顺利,手术时间135min,术中出血20mL。术后30d内无手术并发症,随访30d,体重下降15kg,体重指数(BMI)减少4.9。术后第8天停用一切降糖药物,各项糖尿病检查指标均正常。结论 腹腔镜迷你胃旁路术是相对安全、简单的术式,近期减重效果良好,对2型糖尿病具有很好的治疗效果。 相似文献