全文获取类型
收费全文 | 30230篇 |
免费 | 2228篇 |
国内免费 | 637篇 |
专业分类
耳鼻咽喉 | 234篇 |
儿科学 | 549篇 |
妇产科学 | 834篇 |
基础医学 | 4052篇 |
口腔科学 | 801篇 |
临床医学 | 3134篇 |
内科学 | 6265篇 |
皮肤病学 | 424篇 |
神经病学 | 2515篇 |
特种医学 | 788篇 |
外国民族医学 | 3篇 |
外科学 | 3886篇 |
综合类 | 1508篇 |
现状与发展 | 4篇 |
一般理论 | 13篇 |
预防医学 | 2052篇 |
眼科学 | 866篇 |
药学 | 2273篇 |
6篇 | |
中国医学 | 619篇 |
肿瘤学 | 2269篇 |
出版年
2024年 | 52篇 |
2023年 | 348篇 |
2022年 | 706篇 |
2021年 | 1116篇 |
2020年 | 709篇 |
2019年 | 882篇 |
2018年 | 996篇 |
2017年 | 842篇 |
2016年 | 883篇 |
2015年 | 1028篇 |
2014年 | 1263篇 |
2013年 | 1526篇 |
2012年 | 2254篇 |
2011年 | 2336篇 |
2010年 | 1335篇 |
2009年 | 1141篇 |
2008年 | 1759篇 |
2007年 | 1732篇 |
2006年 | 1766篇 |
2005年 | 1683篇 |
2004年 | 1450篇 |
2003年 | 1256篇 |
2002年 | 1154篇 |
2001年 | 653篇 |
2000年 | 612篇 |
1999年 | 590篇 |
1998年 | 245篇 |
1997年 | 261篇 |
1996年 | 198篇 |
1995年 | 147篇 |
1994年 | 141篇 |
1993年 | 100篇 |
1992年 | 257篇 |
1991年 | 252篇 |
1990年 | 198篇 |
1989年 | 186篇 |
1988年 | 149篇 |
1987年 | 145篇 |
1986年 | 118篇 |
1985年 | 87篇 |
1984年 | 68篇 |
1983年 | 39篇 |
1982年 | 60篇 |
1981年 | 48篇 |
1980年 | 43篇 |
1979年 | 47篇 |
1978年 | 39篇 |
1977年 | 30篇 |
1974年 | 25篇 |
1973年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Marina Quartu Maria Pina Serra Annalisa Manca Paolo Follesa Maria Letizia Lai Marina Del Fiacco 《International journal of developmental neuroscience》2003,21(1):23-33
The immunohistochemical occurrence of the neurotrophin (NT) proteins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-4 (NT-4), and neurotrophin-3 (NT-3) is shown in the pre-term newborn, infant, and adult human post-mortem cerebellum. The NT-like immunoreactive structures were unevenly distributed and showed regional differences among cerebellar lobules and folia. NGF-, NT-4-, and NT-3-positive neuronal perikarya were observed in all specimens examined. At variance with the other neurotrophins, the BDNF antiserum labelled neuronal cell bodies only in newborn life and infancy, as well as extensive nerve fibre systems, whose density increased with age. The NT-antibodies, tested by Western blot on human cerebellum homogenates, revealed immunoreactive bands corresponding to proteins of heterogenous molecular weight. The results obtained provide a first demonstration of the tissue localization of the NTs in the human cerebellum from perinatal to adult age, thus suggesting their involvement in the development, differentiation and maintenance of the cerebellar connectivity. Codistribution of the four NTs or sets of them was observed in cortical and deep nuclei neurons. Multiple trophic roles for NTs, encompassing the classic target-derived and local mechanisms of support, are envisaged as significant in development, differentiation, and maintenance of the human cerebellar connectivity. 相似文献
72.
显微定量法测定中成药中猪牙皂的含量 总被引:2,自引:0,他引:2
目的 :制定猪牙皂在脐风散与惊风散中的显微定量标准。方法 :用显微定量法 ,以猪牙皂特有的石细胞为显微特征物 ,对脐风散与惊风散中的猪牙皂进行测定。结果 :猪牙皂含量与每毫克特征数呈显著的线性正相关 ,回归方程为 y =61 .42 x -1 .1 0× 1 0 - 3(γ=1 .0 0 ,α=0 .0 5 )。结论 :显微定量法测定脐风散与惊风散中猪牙皂的含量是可行的 ,结果可靠 相似文献
73.
葡萄球菌属对常用抗生素耐药情况调查 总被引:7,自引:1,他引:6
目的:了解葡萄球菌属,特别是耐甲氧西林葡萄球菌(MRS)的耐药情况,为临床用药提供参考。方法:从2002年1-7月送检的住院病人的血、痰、脓液、分泌物等标本中分离出的金黄色葡萄球菌、表皮葡萄球菌及其他血浆凝固酶阴性的葡萄球菌共105株,并进行药敏和多重耐药分析。结果:MRS的分离率较高,为68.6%,耐甲氧西林金黄色葡萄球菌(MRSA)为69.2%;耐甲氧西林表皮葡萄球菌(MRSE)为63.3%。MRS较非耐甲氧西林葡萄球菌(MSS)耐药率明显高,且MRS比MSS多重耐率高得多;MRSA对四种不同作用机制的抗生素;泰能、阿米卡星、环丙沙星、复方新诺明具有很高的多重耐药率,达到50%以上。结论:鉴于MRS的高分离率和多重耐药率,在治疗感染性疾病时,应加强病原学检查,提高标本鉴定的阳性率;在有效的治疗MRS感染的同时还应注意遏制MRS的产生。 相似文献
74.
Simone Maschauer Olaf Prante Markus Hoffmann J Thiess Deichen Torsten Kuwert 《Journal of nuclear medicine》2004,45(3):455-460
The contribution of (18)F-FDG uptake by endothelial cells to uptake values measured by PET in various tissues is as yet unclear. We therefore sought to characterize (18)F-FDG uptake in an in vitro model of human endothelial cells. METHODS: Commercially obtained human umbilical vein endothelial cells (HUVECs) were seeded in 6-multiwell plates 48-96 h before incubation with 1-2 MBq (18)F-FDG per well. Radioactivity measurements were performed after washing and mechanical dissolvation of the cellular monolayers. Cellular (18)F-FDG uptake was referred to protein concentration. This experimental protocol was subsequently varied to study the effect of different parameters of interest. Furthermore, radio-thin-layer chromatography was used to identify intracellular (18)F-FDG metabolites. (18)F-FDG uptake in HUVECs was compared with that by a human monocyte-macrophage (HMM) preparation and by glioblastoma cells (GLIOs) under identical experimental conditions. RESULTS: (18)F-FDG accumulated in HUVECs in a time-dependent manner and was trapped mainly as (18)F-FDG-6-phosphate and (18)F-FDG-1,6-diphosphate. Unlabeled glucose and cytochalasin B competitively inhibited (18)F-FDG uptake, whereas phlorizin had no significant effect. Glucose deprivation significantly enhanced (18)F-FDG uptake by a factor of 2.7, whereas sodium depletion had no significant influence. HUVECs treated with vascular endothelial growth factor (VEGF) showed a significant 82% increase in (18)F-FDG accumulation after a 2-h exposure to 50 ng/mL VEGF. (18)F-FDG uptake in HUVECs was significantly higher than that in HMMs and in the range of the uptake values measured in GLIOs. CONCLUSION: (18)F-FDG accumulates in HUVECs by mechanisms analogous to those in neoplastic cells or neurons. VEGF significantly stimulates endothelial (18)F-FDG uptake. The observed differences in (18)F-FDG uptake between HUVECs, HMMs, and GLIOs are difficult to extrapolate to in vivo conditions but stimulate further studies on the contribution of endothelial (18)F-FDG uptake to the overall uptake of that tracer in neoplastic or vascular lesions. 相似文献
75.
76.
高压交变电磁场对心血管疾病康复的应用 总被引:2,自引:0,他引:2
应用高压交变电磁场对134例冠心病及高血压病患者进行临床应用,结果显效67例,好转55例,无效12例;有效地改善了脂蛋白代谢,降低TG、Tc、LDL-c及致动脉硬化指数.升高HDL-c浓度;降低了高血压病患者的血压;改善了冠心病患者的心电图;同时可改善心功能参数及心室负荷。由此可见,高压交变电磁场能抗动脉粥样硬化,对心血管疾病有显著的治疗作用。 相似文献
77.
Reports of the incidence of postoperative deep vein thrombosis in the Chinese population of Taiwan are few in the literature. Over a 3 year period, the fibrinogen degradation products test, the pulse volume recorder, and venography were used to study 220 patients undergoing major operations at the Veterans General Hospital in Taipei, Taiwan. Deep vein thrombosis was found in 17 patients (7.7 percent). A comparison of the three diagnostic methods showed that the sensitivities of the fibrinogen degradation products test and the pulse volume recorder were 56.3 percent and 93.7 percent, respectively; the specificities, 97.4 percent and 95.7 percent, respectively; and the accuracies, 85.5 percent and 95.5 percent, respectively. These results support the combined use of the fibrinogen degradation products test and the pulse volume recorder for screening and diagnosing deep vein thrombosis. 相似文献
78.
Human trophoblast and choriocarcinoma expression of the growth
factor pleiotrophin attributable to germ-line insertion of
an endogenous retrovirus 下载免费PDF全文
79.
80.
Guerriero S Ajossa S Lai MP Risalvato A Paoletti AM Melis GB 《Human reproduction update》1999,5(5):515-529
This review describes the usefulness of colour Doppler energy (CDE) (or power Doppler) imaging to measure vascularization in the female reproductive tract. CDE imaging is characterized by an increased sensitivity to flow, and thus may be useful in low-flow states and when optimal Doppler angles cannot be obtained. In addition, longer segments of vessels and more individual vessels can be visualized with CDE imaging. The role of CDE imaging in the evaluation of stromal vasculature in normal and in polycystic ovaries is described, and the relationship between follicular vascularity and outcome following in-vitro fertilization are discussed, together with the findings obtained from the evaluation of thecal arteriole of corpus luteum in early pregnancy. The fundamental role of CDE imaging in differentiation among ovarian masses is also reviewed. We summarize the role of CDE imaging in pregnancy, and describe two new applications of three-dimensional power Doppler sonography and the use of ultrasound contrast media. In conclusion, CDE imaging can replace conventional colour Doppler when the information on the direction of flow is not useful. Moreover, the technique appears superior to others for describing microvascular architecture and determining the presence or absence of flow. 相似文献