全文获取类型
收费全文 | 64364篇 |
免费 | 4759篇 |
国内免费 | 1760篇 |
专业分类
耳鼻咽喉 | 839篇 |
儿科学 | 1216篇 |
妇产科学 | 2215篇 |
基础医学 | 8102篇 |
口腔科学 | 1171篇 |
临床医学 | 6853篇 |
内科学 | 12043篇 |
皮肤病学 | 1198篇 |
神经病学 | 3964篇 |
特种医学 | 2695篇 |
外国民族医学 | 6篇 |
外科学 | 8569篇 |
综合类 | 4320篇 |
现状与发展 | 7篇 |
一般理论 | 11篇 |
预防医学 | 3516篇 |
眼科学 | 1402篇 |
药学 | 5345篇 |
21篇 | |
中国医学 | 1678篇 |
肿瘤学 | 5712篇 |
出版年
2023年 | 525篇 |
2022年 | 1322篇 |
2021年 | 2180篇 |
2020年 | 1309篇 |
2019年 | 1625篇 |
2018年 | 2004篇 |
2017年 | 1519篇 |
2016年 | 1570篇 |
2015年 | 2339篇 |
2014年 | 2921篇 |
2013年 | 3399篇 |
2012年 | 4823篇 |
2011年 | 4696篇 |
2010年 | 3009篇 |
2009年 | 2634篇 |
2008年 | 3558篇 |
2007年 | 3551篇 |
2006年 | 3405篇 |
2005年 | 3137篇 |
2004年 | 2840篇 |
2003年 | 2717篇 |
2002年 | 2359篇 |
2001年 | 1852篇 |
2000年 | 1615篇 |
1999年 | 1349篇 |
1998年 | 585篇 |
1997年 | 481篇 |
1996年 | 444篇 |
1995年 | 393篇 |
1994年 | 379篇 |
1993年 | 252篇 |
1992年 | 716篇 |
1991年 | 583篇 |
1990年 | 538篇 |
1989年 | 495篇 |
1988年 | 435篇 |
1987年 | 440篇 |
1986年 | 369篇 |
1985年 | 308篇 |
1984年 | 238篇 |
1983年 | 199篇 |
1982年 | 120篇 |
1981年 | 130篇 |
1980年 | 107篇 |
1979年 | 208篇 |
1978年 | 164篇 |
1977年 | 107篇 |
1976年 | 114篇 |
1975年 | 106篇 |
1974年 | 99篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
以往以乳头为圆心的同心圆剥离法常形成假体的移位,使假体的体表轮廓与前方的自然乳房分离,产生“双重乳房”现象。在研究了女性不同体位下不同的乳房形态及总结了以前的经验后,提出了偏心圆剥离的概念。偏心圆手术设计方法:以乳头为圆心,按其内侧、下侧为直径3/5的比例,以外侧、上侧为直径2/5的比例,形成一偏心圆的剥离范围。偏心圆的直径因考虑到假体的不同形态、大小及底面直径,以经中心假体纵截面的周长的1/2再放大2cm,作为剥离范围的直径。自1991年10月以来已应用了176例,无一术后移位现象,也没有固较多地剥离胸大肌内、下侧止点纤维而影响上肢活动。自然乳房并不是静态的圆锥形或半球形,它具有伸缩的组织学特点,又有随体位变动而变化的特点。用偏心圆法剥离,可使置入的假体与前方的自然乳房融为一体,消除“双重乳房”现象,而成为“真实”的乳房。同时也应积极寻找一种与身体组织相容性好的,弹性、比重与女性乳腺较为一致的,假体容量相对恒定的生物性材料。这样隆乳术才可以更广泛地开展。 相似文献
72.
73.
74.
Alex Y. Chang Z. Nora Tu Julia L. Smith Philip Bonomi Thomas J. Smith Peter H. Wiernik Ronald Blum 《Investigational new drugs》1995,13(2):137-141
Summary Fifty-five patients with metastatic non-small cell lung cancer (NSCLC) were entered into this phase II randomized study for evaluating three new agents: gallium nitrate, amonafide and teniposide. The patients had to have ECOG performance status 0 or 1, no prior chemotherapy, and adequate hematological, hepatic and renal functions. Forty-seven patients were eligible and evaluable. Fourteen were randomized to receive gallium nitrate, 18 to amonafide and 15 to teniposide. Seventy-four percent of eligible patients were male. The majority of patients (89%) had an ECOG performance status 1. ECOG grade 4 toxicity occurred twice in patients on gallium nitrate, seven times on amonafide and 18 times on teniposide. The cause of death was attributed to amonafide in one patient (from sepsis) and to teniposide in two patients (due to infection and leukopenia). There was no objective response in all the patients entered. The overall survival times ranged from 2 weeks to 156 weeks with a median of 23 weeks. There were no survival differences among the three treatment arms. We conclude that gallium nitrate, amonafide and teniposide are inactive in metastatic NSCLC and do not warrant any further testing in this disease.The contents of this study is solely the responsibility of the authors and does not necessarily represent the official views of the National Cancer Institute. 相似文献
75.
我国较贫困地区农村学龄前儿童膳食状况 总被引:5,自引:0,他引:5
对1985~1989年7省较贫困的18个乡农村儿童膳食调查资料采用平均摄入量、临界值及概率法进行了总结分析。结果表明,6~24月龄母乳喂养儿的辅食品种单一,数量不足。断奶儿童各年龄组热能、蛋白质摄入量的平均值分别达RDA的92%~104%和76%~84%,但以RDA为界值,仍有53%~62%及74%~85%的儿童热能、蛋白质摄入量低,用概率法分析蛋白质、钙、维生素A、B2、C及铁摄入不足的人数比例分别是50%~60%、93%~97%、51%~87%、74%~86%、58%~66%和12%~47%。热能、蛋白质摄入量低于RDA值儿童的身高、体重明显低于摄入量高于RDA值的儿童。 相似文献
76.
HERMAN TOURNAYE RONNY JANSSENS PAUL DEVROEY RK VAN STEIRTEGHEM 《International journal of andrology》1994,17(1):1-8
In order to evaluate the effects of pentoxifylline on sperm motility and longevity, a controlled in-vitro study was conducted on normozoospermic donor semen samples using the Cellsoft automated system for sperm motility analysis. After incubation and selection, pentoxifylline was found to improve the recovery of spermatozoa and to increase their velocity. In the subgroup of progressively motile spermatozoa, curvilinear velocity was also enhanced. It is concluded that pentoxifylline has an effect on the vigour, but not on the pattern, of sperm motion. Pentoxifylline did not improve the motility characteristics of senescent spermatozoa in normozoospermic sperm samples. Sperm survival, as shown by supra-vital staining, and motility longevity both decreased with time after pentoxifylline treatment. 相似文献
77.
Using the polymerase chain reaction (PCR)-based single strand conformation polymorphism (SSCP) analysis, we have examined the highly conserved regions of the p53 gene in 58 biopsy samples of head and neck tumors. Mutations were found in 13/58 (23%) tumor specimens, but not in 6 normal tissues. Ten of 13 mutations were due to single base changes and the remaining 3 were 1- or 8-base deletion mutants. These mutations were clustered in exons 5 and 7 and resulted in amino acid changes. Our results seem to indicate that mutations in the p53 gene contribute to a significant number of cases of the head and neck tumors including 20% of nasopharyngeal carcinoma biopsies. The relationship of Epstein-Barr virus or human papillomavirus and p53 gene mutations in this group of cancers was also analyzed and discussed. 相似文献
78.
79.
Ca-mediated stimulation of Cl secretion by reactive oxygen metabolites in human colonic T84 cells. 下载免费PDF全文
H Tamai T S Gaginella J F Kachur M W Musch E B Chang 《The Journal of clinical investigation》1992,89(1):301-307
Monochloramine (NH2Cl), a granulocyte-derived reactive oxygen metabolite (ROM), increases short-circuit current (Isc) in cultured T84 monolayers in a concentration-dependent manner up to nonlethal concentrations of 75 microM. Isc increases slowly after NH2Cl, reaching a peak value of 18 +/- 2 microA/cm2 20 min after addition. The Isc changes are persistent (lasting over 20-30 min), depend on medium Cl, and are inhibitable with bumetanide. 36Cl flux studies demonstrated that NH2Cl increases serosa-to-mucosa flux of Cl without changing mucosa-to-serosa flux, consistent with stimulation of electrogenic Cl secretion. Isc responses to NH2Cl, but not PGE2, are dependent on medium calcium. As demonstrated in fura-2-loaded T84 cells, NH2Cl increases free cytosolic calcium by influx of extracellular Ca2+ and by release of Ca2+ from endogenous stores. However, NH2Cl had no effect on phosphatidylinositol metabolism or cyclic nucleotide levels. We conclude that ROM directly stimulate electrolyte secretion, an effect in part mediated by increases in cytosolic Ca2+, possibly through increasing Ca2+ permeability of cellular membranes. 相似文献
80.
挫伤性屈光不正的眼超声生物学检测 总被引:4,自引:0,他引:4
对112例挫伤性屈光不正患者进行了超声生物学检测。结果提示,挫伤性近视患者眼球解剖结构存在两大变,即晶体前移和厚度增加,超声前房深度、晶本厚度在伤后的检测结果与对照组相比具显著性差异。并对挫伤屈光不正的发生机制进行了探讨。 相似文献