全文获取类型
收费全文 | 7299篇 |
免费 | 700篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 105篇 |
儿科学 | 242篇 |
妇产科学 | 174篇 |
基础医学 | 1150篇 |
口腔科学 | 185篇 |
临床医学 | 729篇 |
内科学 | 1499篇 |
皮肤病学 | 60篇 |
神经病学 | 754篇 |
特种医学 | 260篇 |
外科学 | 1046篇 |
综合类 | 126篇 |
一般理论 | 3篇 |
预防医学 | 525篇 |
眼科学 | 278篇 |
药学 | 465篇 |
中国医学 | 13篇 |
肿瘤学 | 416篇 |
出版年
2023年 | 30篇 |
2021年 | 160篇 |
2020年 | 103篇 |
2019年 | 163篇 |
2018年 | 172篇 |
2017年 | 126篇 |
2016年 | 158篇 |
2015年 | 167篇 |
2014年 | 228篇 |
2013年 | 288篇 |
2012年 | 442篇 |
2011年 | 524篇 |
2010年 | 285篇 |
2009年 | 236篇 |
2008年 | 478篇 |
2007年 | 540篇 |
2006年 | 475篇 |
2005年 | 442篇 |
2004年 | 480篇 |
2003年 | 384篇 |
2002年 | 359篇 |
2001年 | 53篇 |
2000年 | 51篇 |
1999年 | 57篇 |
1998年 | 89篇 |
1997年 | 65篇 |
1996年 | 58篇 |
1995年 | 55篇 |
1994年 | 65篇 |
1993年 | 49篇 |
1992年 | 39篇 |
1991年 | 35篇 |
1990年 | 30篇 |
1989年 | 26篇 |
1988年 | 31篇 |
1987年 | 33篇 |
1986年 | 36篇 |
1985年 | 43篇 |
1984年 | 27篇 |
1983年 | 42篇 |
1982年 | 53篇 |
1981年 | 59篇 |
1980年 | 48篇 |
1979年 | 30篇 |
1978年 | 38篇 |
1977年 | 37篇 |
1976年 | 32篇 |
1975年 | 28篇 |
1974年 | 29篇 |
1965年 | 26篇 |
排序方式: 共有8030条查询结果,搜索用时 15 毫秒
21.
D Jabbari 《Journal of medical ethics》1990,16(1):35-40
It is a common feature of debates on the regulation of reproductive medicine to find law portrayed as a crude form of intervention consisting in the imposition of inflexible rules on doctors and medical researchers. This paper argues that this view must be replaced by a more accurate assessment of the law's potential role in the regulation of reproductive medicine. From an analysis of the White Paper on human fertilisation and embryology, and in particular the proposed Statutory Licensing Authority, the author contends that far from being an inflexible method of regulation law can foster discussion and compromise. 相似文献
22.
23.
Eric K. Outwater Katsuyoshi Ito Evan Siegelman C. Edwin Martin Manoj Bhatia Donald G. Mitchell 《Journal of magnetic resonance imaging : JMRI》1997,7(6):1033-1039
The purpose of this study is to describe a subset of atypical hepatic hemangiomas that enhance rapidly and diffusely and to determine whether heavily T2-weighted images could distinguish between atypically enhancing liver hemangiomas and hypervascular malignancies. A retrospective search of MR records identified seven patients with liver hemangiomas that demonstrated diffuse early enhancement and 23 patients with biopsy-proven malignant liver lesions that were hypervascular on dynamic gadolinium-enhanced MR images. Quantitative analysis of signal intensity measurements was performed on the T2-weighted images, heavily T2-weighted (TE < 140), and dynamic gadolinium-enhanced images. Blinded reader comparison of the T2-weighted images and gadolinium-enhanced images was performed. Hypervascular hemangiomas enhanced to a greater degree than hypervascular malignant liver lesions on the early phase gadolinium-enhanced images. Perilesional parenchymal enhancement was demonstrated in five cases of rapidly enhancing hemangiomas. Signal intensity and contrast-to-noise ratios on the heavily T2-weighted images of the hemangiomas were significantly greater than that of the hypervascular malignant lesions (P < .05). Hemangiomas were differentiated from the hypervascular malignant liver lesions with high accuracy (97–100%) by three blinded readers based on the T2-weighted images. A subset of hemangiomas have atypical rapid diffuse enhancement on dynamic gadolinium-enhanced images. These atypical hemangiomas can be distinguished from hypervascular malignant liver lesions on T2-weighted MR images. 相似文献
24.
Vlado Simko Shoukry Michael Jeffrey Katz Edwin Oberstein rea Popescu 《Alcoholism, clinical and experimental research》1992,16(4):795-799
Considering the well-documented protection of acetylcysteine (AC) in hepatotoxicity related to acetaminophen, we studied the preventive potential of AC against mild hepatotoxicity of CCl4, potentiated with ethyl alcohol (ETH) and the role of tissue glutathione. Rats fed a liquid diet with 30% of energy from ETH, had-intraperitoneal CCl4 administered in three injections, at 7-day intervals. AC was ingested at the level for acetaminophen overdose. ETH markedly potentiated the injury induced by CCl4, as evidenced by higher values of serum alanine aminotransferase (ALT), urinary bile acids (BA), serum creatinine, histological score of liver cell necrosis, mortality and by lower body weights and lower liver glutathione, when compared with CCl4 alone. Protective effect of AC consisted of a lesser hepatocytic necrosis, better body weights and higher liver glutathione. We conclude, that AC favorably modifies liver damage induced by CCl4 and potentiated with ETH. There is a preventive role for AC in subjects who combine ETH overuse with exposure to hepatotoxic xenobiotics, whose toxicity is modified by tissue glutathione. 相似文献
25.
26.
Cells of the immune system are shown to produce peptide hormones whose production was once thought to be restricted to neuroendocrine tissue. Interestingly, in some cases, very specific stimuli elicit the production of one species of neuropeptide hormone. In other instances, it appears that some peptide hormones are constitutively produced. In either situation, the various immunocyte-derived hormones have biological activity in endocrinological assays. In the present report, a review of the various neuroendocrine hormones produced by cells of the immune system is discussed. 相似文献
27.
C Joseph Muniz Arthur C Fleischer Edwin F Donnelly Murray J Mazer 《Journal of ultrasound in medicine》2002,21(2):129-133
OBJECTIVE: To assess the accuracy of three-dimensional color Doppler sonography and uterine artery arteriography in depicting changes in fibroid vascularity before and after embolization. METHODS: Preembolization and postembolization three-dimensional color Doppler sonography and selective uterine artery arteriography were retrospectively compared in 15 patients who underwent uterine artery embolization for treatment of symptomatic fibroids. Three-dimensional color Doppler sonography was performed by using a scanner with color power angiographic imaging capability. Vascularity was quantified by using an estimation of power-weighted pixel density as described by our group in previously published studies. Uterine artery arteriography was performed by using a standard selective microcatheter embolization technique. For purposes of comparison, fibroids were classified as either hypervascular or hypovascular relative to myometrial vascularity before and minutes to several hours after uterine artery embolization. Changes in fibroid vascularity (i.e., from hypervascular to hypovascular) as depicted by three-dimensional color Doppler sonography were compared with those shown on uterine artery arteriography and classified as being in agreement or disagreement. RESULTS: In 13 (87%) of 15 patients there was agreement; in 2 (13%) of 15 there was disagreement. In both cases of disagreement, three-dimensional color Doppler sonography showed collateral flow not depicted by uterine artery arteriography The mean reduction in quantitated vascularity after uterine artery embolization was 44% (range, 19%-78%). CONCLUSIONS: Three-dimensional color Doppler sonography accurately depicts fibroid vascularity and in some cases can reveal collateral flow not depicted by uterine artery arteriography. 相似文献
28.
29.
30.
失控的炎性反应和补体活化参与多脏器功能衰竭的发病过程。而因肠粘膜屏障功能衰竭造成的大量肠道细菌和内毒素侵入体内协同作用形成的肠源性感染在多脏器功能衰竭发病中所起的作用又日益受到关注。本研究给动物注射一种补体活化和炎性反应的活化因子——酵母多糖,观察炎症和感染两者间的内在关联性。结果发现,亚致死量的酵母多糖(0.1mg/g)可损伤肠粘膜屏障而导致肠道细菌侵入体内。而蛋白质营养不良却显著强化了酵母多糖的上述病理效应,使动物形成致死性的全身性肠源性感染,感染的严重性和动物的病死率随营养不良的程度进行性增高。结果表明,在体内失控的炎性反应和肠源性感染有协同致病效应。 相似文献