全文获取类型
收费全文 | 68392篇 |
免费 | 4732篇 |
国内免费 | 2254篇 |
专业分类
耳鼻咽喉 | 485篇 |
儿科学 | 1316篇 |
妇产科学 | 2924篇 |
基础医学 | 7558篇 |
口腔科学 | 1548篇 |
临床医学 | 5400篇 |
内科学 | 6650篇 |
皮肤病学 | 880篇 |
神经病学 | 4247篇 |
特种医学 | 1868篇 |
外国民族医学 | 8篇 |
外科学 | 4979篇 |
综合类 | 10914篇 |
现状与发展 | 3篇 |
一般理论 | 6篇 |
预防医学 | 6378篇 |
眼科学 | 1743篇 |
药学 | 9830篇 |
82篇 | |
中国医学 | 5786篇 |
肿瘤学 | 2773篇 |
出版年
2024年 | 203篇 |
2023年 | 981篇 |
2022年 | 1737篇 |
2021年 | 2434篇 |
2020年 | 2218篇 |
2019年 | 2111篇 |
2018年 | 2049篇 |
2017年 | 2092篇 |
2016年 | 2068篇 |
2015年 | 2005篇 |
2014年 | 3985篇 |
2013年 | 4875篇 |
2012年 | 4006篇 |
2011年 | 4483篇 |
2010年 | 3652篇 |
2009年 | 3254篇 |
2008年 | 3182篇 |
2007年 | 3302篇 |
2006年 | 2878篇 |
2005年 | 2574篇 |
2004年 | 2114篇 |
2003年 | 2069篇 |
2002年 | 1588篇 |
2001年 | 1492篇 |
2000年 | 1212篇 |
1999年 | 1145篇 |
1998年 | 986篇 |
1997年 | 1010篇 |
1996年 | 903篇 |
1995年 | 877篇 |
1994年 | 751篇 |
1993年 | 636篇 |
1992年 | 588篇 |
1991年 | 534篇 |
1990年 | 533篇 |
1989年 | 469篇 |
1988年 | 348篇 |
1987年 | 284篇 |
1986年 | 348篇 |
1985年 | 465篇 |
1984年 | 442篇 |
1983年 | 268篇 |
1982年 | 346篇 |
1981年 | 280篇 |
1980年 | 306篇 |
1979年 | 222篇 |
1978年 | 185篇 |
1977年 | 176篇 |
1976年 | 162篇 |
1975年 | 113篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
石刻雕塑作业劳动卫生学调查及实验研究 总被引:1,自引:0,他引:1
测定了石雕作业粉尘浓度,几何平均浓度为82.35~3.67mg/m3。工人职业性健康检查结果,接尘工人的咽部充血、咳嗽、咯痰检出率高于对照组;肺功能低下的检出率也高于对照组。该厂自1972年以来发生尘肺患者17例,其病情发展和晋期缓慢,发病工龄长。动物实验研究表明,石雕粉尘有轻微的致纤维化作用。 相似文献
52.
Cellular distribution of the new growth factor Pleiotrophin (HB-GAM) mRNA in developing and adult rat tissues 总被引:7,自引:0,他引:7
J. M. Vanderwinden P. Mailleux S. N. Schiffmann J. J. Vanderhaeghen 《Anatomy and embryology》1992,186(4):387-406
Summary Pleiotrophin (PTN), also known as HBGAM, belongs to an emerging cytokine family unrelated to other growth factors. We report here the first comprehensive study using in situ hybridization on the cellular distribution of this new heparin-binding growth factor mRNA in rat tissues. PTN mRNA was developmentally expressed in many — but not all — neuroectodermal and mesodermal lineages, whilst no PTN mRNA was detected in endoderm, ectoderm and trophoblast. PTN mRNA was found in the nervous system throughout development, with a post-natal peak of expression. In the adult nervous system, significant expression persisted in hippocampal CA1 pyramidal neurons and in cortical neurons, but also in different non-neuronal cells types in various locations (olfactory nerve, cerebellar astrocytes, pituicytes, Schwann cells surrounding the neurons in sensory ganglia). PTN mRNA was also found during development in the mesenchyme of lung, gut, kidney and reproductive tract, in bone and cartilage progenitors, in dental pulp, in myoblasts, and in several other sites. Expression was differently regulated in each location, but usually faded around birth. In the adult, PTN mRNA was still present in the meninges, the iris, the Leydig cells of the testis and in the uterus. PTN mRNA was also strongly expressed in the basal layers of the tongue epithelium, which is the only epithelium and ectodermal derivative to express PTN mRNA, and this only after birth. PTN is known to be a growth factor for perinatal brain neurons and a mitogen for fibroblasts in vitro. Recently, trophic effects on epithelial cells and a role as a tumour growth factor have been reported. The mechanisms of regulation and the functions of PTN are however still uncertain. Its expression pattern during development suggests important roles in growth and differentiation. Moreover, the presence of PTN mRNA in several adult tissues and the up-regulation of PTN mRNA expression in the gravid uterus indicate that PTN also has physiological functions during adulthood. 相似文献
53.
Comparative bactericidal exposures for selected oral bacteria using carbon dioxide laser radiation 总被引:2,自引:0,他引:2
D N Dederich M A Pickard A S Vaughn J Tulip K L Zakariasen 《Lasers in surgery and medicine》1990,10(6):591-594
Although relatively high CO2 laser energies have been shown to sterilize root canals, the response of several bacterial strains to decreasing exposures of CO2 laser energy remains unknown. Freshly grown bacterial cells were irradiated on glass microscope coverslips. A comparison of equivalent energy exposures with differing parameters was made on the bacterial viability. No statistically significant difference was found in the energy required to kill closely related bacterial species. However, the energy density required to kill greater than 99.5% of the bacteria is less than 200 J/cm2, much less than that shown to sterilize in a previous study. 相似文献
54.
Treatment of rat heart grafts with PUVA, the combination of the photosensitizer 8-methoxypsoralen and longwave ultraviolet light, leads to a prolonged transplant survival in allogeneic recipients. A PUVA treatment of the recipient rats, performed for 7 consecutive days after transplantation, prolonged graft survival even more effectively. This may be due to the systemic immunomodulatory effects of PUVA in the recipient. One of the mediators is urocanic acid, which is transformed by ultraviolet light in the skin from its trans- to the cis-isomer, which, in turn, acts as a mediator on the immune system. An injection of cisurocanic acid into graft recipients for 7 consecutive days after transplantation resulted in prolonged graft survival; in 40% of the rats, permanent graft acceptance was observed. The significance of these results for clinical organ transplantation is discussed. 相似文献
55.
运用人力资源管理策略 改革病房护理管理 总被引:3,自引:0,他引:3
从发展成功管理的共同文化,创建优质服务病房;建立有效的护理人力资源管理支持系统,创建适合于专业护理的工作环境,确保护理质量;以病人为中心,以病人满意度作为衡量护理工作优劣的标准三个方面介绍了乐山市人民医院运用护理人力资源管理策略,改革病房护理管理,创建优质服务病房的实践经验及其效果。 相似文献
56.
真皮下血管网岛状皮瓣抗菌力的实验研究 总被引:2,自引:0,他引:2
为研究真皮下血管网薄皮瓣用于感染创面的可行性,在家猪臀部两侧分别形成以旋髂深血管主干分支为蒂的传统岛状皮瓣和远侧50%修薄的真皮下血管网岛状皮瓣。用细菌计数、吖啶橙荧光染色测定白细胞吞噬指数和白细胞内杀菌率,应用激光多普勒、墨汁灌注、透明标本等方法,对两种皮瓣的抗菌力作自身对照研究。结果表明,真皮下血管网岛状皮瓣的抗菌力明显降低,可能与皮瓣修薄后血供减少,白细胞功能相应降低有关。 相似文献
57.
应用原位杂交技术,观察了二乙基亚硝胺(DEN)诱发大鼠肝癌前病变组织中胎盘型谷胱甘肽S转移酶(GST-P)mRNA的表达。结果显示,GST-PmRNA主要在癌前病变肝组织中的变异灶及灶外卵圆形细胞内表达,且在变异灶间或和同一灶内阳性细胞间表达程度不尽一致,而正常肝、再生肝组织中未见其表达。提示在分子水平上变异灶细胞及卵圆型细胞可能成为实验性肝癌的癌前期细胞 相似文献
58.
Formulation and in Vitro-in Vivo Evaluation of Sustained-Release Lithium Carbonate Tablets 总被引:1,自引:0,他引:1
Çiftçi Kadriye Çapan Yilmaz Öztürk Orhan Hincal A. Atilla 《Pharmaceutical research》1990,7(4):359-363
The release of lithium carbonate incorporated into polymethylmethacrylate, poly vinyl chloride, hy-drogenated vegetable oil, and carbomer matrix tablets was studied in vitro. The formulation containing 10% carbomer showed a sustained-release profile comparable to that of a standard, commercially available, sustained-release preparation containing 400 mg lithium carbonate embedded in a composite material. In vivo the newly formulated and standard sustained-release lithium carbonate tablets were compared to an oral solution and conventional lithium carbonate tablets in 12 healthy subjects. These crossover studies showed that the sustained-release tablets produced a flatter serum concentration curve than the oral solution and conventional tablet, without loss of total bioavailability. 相似文献
59.
浅谈电子文档的原始性和真实性及法律证据作用 总被引:3,自引:0,他引:3
董中印 《安徽卫生职业技术学院学报》2005,4(2):62-63,57
该文针对电子文件或档案的原始性真实性与电子档案的法律证据作用,参考了最新的研究结果,并提出了自己的思考,逐步探讨了它们的涵义及关系. 相似文献
60.
目的研究肝癌病例癌组织、癌旁组织及非癌肝组织中HOXA9 mRNA的表达及其临床意义.方法标本经10%中性福尔马林固定后常规制作石蜡包埋切片,HOXA9 mRNA行原位杂交检测.结果临床分析发现术后血清AFP值、AFU值、Glo值、PAB值及SHCSP阳性率均有明显减少.癌组织HOXA9mRNA阳性表达评分(1.94±1.69)明显低于非癌肝组织(3.17±1.70),两者有显著差异;癌旁组织HOXA9mRNA阳性表达评分(2.54±1.20)与非癌肝组织及癌组织无显著差异.癌组织、癌旁组织及非癌肝组织三者HOXA9mRNA阳性表达率(54.84%、76.92%、83.33%)无显著差异.除HCC中HOXA9RNA阳性表达评分(1.81±1.78)显著低于MHC(2.75±0.50)外,HOXA9mRNA表达阳性率及阳性评分与癌分化程度、AFP值、SHCSP是否阳性、AFU值、肝硬化有无、转移情况、有无癌栓、大体形态及肿块最大径等临床病理特征均无明显关系.结论本研究结果显示HOXA9mRNA可能与肝癌的发生有密切关系.临床上检测HOXA9mRNA的表达情况对肝癌的早期发现和早期诊断可能有较重要的临床意义,值得深入研究. 相似文献