全文获取类型
收费全文 | 324篇 |
免费 | 25篇 |
国内免费 | 13篇 |
专业分类
儿科学 | 29篇 |
妇产科学 | 2篇 |
基础医学 | 23篇 |
口腔科学 | 4篇 |
临床医学 | 45篇 |
内科学 | 80篇 |
皮肤病学 | 7篇 |
神经病学 | 7篇 |
特种医学 | 84篇 |
外科学 | 22篇 |
综合类 | 10篇 |
预防医学 | 11篇 |
眼科学 | 1篇 |
药学 | 14篇 |
肿瘤学 | 23篇 |
出版年
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 6篇 |
2015年 | 6篇 |
2014年 | 11篇 |
2013年 | 10篇 |
2012年 | 4篇 |
2011年 | 5篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 9篇 |
2007年 | 19篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 2篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 1篇 |
2000年 | 5篇 |
1999年 | 16篇 |
1998年 | 24篇 |
1997年 | 21篇 |
1996年 | 26篇 |
1995年 | 25篇 |
1994年 | 14篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 11篇 |
1988年 | 11篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 4篇 |
1975年 | 2篇 |
排序方式: 共有362条查询结果,搜索用时 695 毫秒
51.
52.
Matson GB; Twieg DB; Karczmar GS; Lawry TJ; Gober JR; Valenza M; Boska MD; Weiner MW 《Radiology》1988,169(2):541-547
Localized phosphorus-31 magnetic resonance (MR) spectroscopy in humans has previously been accomplished with surface coils by means of depth-resolved surface coil spectroscopy or rotating frame experiments, in which the extent of tissue sampled critically depends on surface coil placement. The authors' goal was to modify the surface coil image-selected in vivo spectroscopy (ISIS) experiment to accomplish three-dimensional volume selection through application of selective pulses in the presence of B0 gradients. Advantages of ISIS include the ability to use proton images to define the volume of interest (VOI) and reduced dependence on exact positioning of the surface coil. However, rapid replication of the surface coil ISIS experiment can cause spectral contamination from signals originating outside the VOI. A modified version of the ISIS experiment was developed to alleviate contamination under conditions of rapid replication. Applications of localized P-31 MR spectroscopy for observation of high-energy phosphorus metabolites are presented in human liver, heart, and transplanted and normal kidney. 相似文献
53.
54.
55.
56.
Romero DG Plonczynski MW Gomez-Sanchez EP Yanes LL Gomez-Sanchez CE 《Endocrinology》2006,147(8):3889-3897
Regulator of G protein signaling (RGS) proteins interact with Galpha-subunits of heterotrimeric G proteins, accelerating the rate of GTP hydrolysis and finalizing the intracellular signaling triggered by the G protein-coupled receptor-ligand interaction. Angiotensin (Ang) II interacts with its G protein-coupled receptor in zona glomerulosa adrenal cells and triggers a cascade of intracellular signals that regulates steroidogenesis and proliferation. We studied Ang II-mediated regulation of RGS2, the role of RGS2 in steroidogenesis, and the intracellular signal events involved in H295R human adrenal cells. We report that both H295R cells and human adrenal gland express RGS2 mRNA. In H295R cells, Ang II caused a rapid and transient increase in RGS2 mRNA levels quantified by real-time RT-PCR. Ang II effects were mimicked by calcium ionophore A23187 and blocked by calcium channel blocker nifedipine. Ang II effects also were blocked by calmodulin antagonists (W-7 and calmidazolium) and calcium/calmodulin-dependent kinase antagonist KN-93. RGS2 overexpression by retroviral infection in H295R cells caused a decrease in Ang II-stimulated aldosterone secretion but did not modify cortisol secretion. In reporter assays, RGS2 decreased Ang II-mediated aldosterone synthase up-regulation. These results suggest that Ang II up-regulates RGS2 mRNA by the calcium/calmodulin-dependent kinase pathway in H295R cells. RGS2 overexpression specifically decreases aldosterone secretion through a decrease in Ang II-mediated aldosterone synthase-induced expression. In conclusion, RGS2 expression is induced by Ang II to terminate the intracellular signaling cascade generated by Ang II. RGS2 alterations in expression levels or functionality could be implicated in deregulations of Ang II signaling and abnormal aldosterone secretion by the adrenal gland. 相似文献
57.
58.
59.
60.
Claire L Gibson Philip MW Bath Sean P Murphy 《Journal of cerebral blood flow and metabolism》2010,30(4):739-743
Granulocyte colony-stimulating factor (G-CSF) is a candidate neuroprotective factor following cerebral ischemia. To determine whether G-CSF acts partly through the inhibition of nitric oxide synthase (NOS)-2 expression, we administered G-CSF to male NOS-2−/− mice after cerebral ischemia. Although male NOS-2−/− mice exhibit resistance to the gross effects of cerebral ischemia, they display neuronal loss and skilled motor deficits following cerebral ischemia. Administration of G-CSF during reperfusion reduced motor deficit and neuronal loss. Thus, G-CSF is still effective in NOS-2 gene-deficient mice, suggesting that part of the mechanism of action is independent of NOS-2. 相似文献