全文获取类型
收费全文 | 4795篇 |
免费 | 301篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 45篇 |
儿科学 | 222篇 |
妇产科学 | 160篇 |
基础医学 | 493篇 |
口腔科学 | 330篇 |
临床医学 | 413篇 |
内科学 | 1295篇 |
皮肤病学 | 43篇 |
神经病学 | 289篇 |
特种医学 | 581篇 |
外科学 | 432篇 |
综合类 | 70篇 |
一般理论 | 1篇 |
预防医学 | 292篇 |
眼科学 | 48篇 |
药学 | 210篇 |
中国医学 | 3篇 |
肿瘤学 | 198篇 |
出版年
2021年 | 53篇 |
2020年 | 26篇 |
2019年 | 34篇 |
2018年 | 50篇 |
2017年 | 32篇 |
2016年 | 48篇 |
2015年 | 64篇 |
2014年 | 78篇 |
2013年 | 142篇 |
2012年 | 135篇 |
2011年 | 121篇 |
2010年 | 137篇 |
2009年 | 106篇 |
2008年 | 131篇 |
2007年 | 131篇 |
2006年 | 143篇 |
2005年 | 132篇 |
2004年 | 160篇 |
2003年 | 117篇 |
2002年 | 125篇 |
2001年 | 134篇 |
2000年 | 124篇 |
1999年 | 139篇 |
1998年 | 178篇 |
1997年 | 162篇 |
1996年 | 170篇 |
1995年 | 137篇 |
1994年 | 113篇 |
1993年 | 114篇 |
1992年 | 121篇 |
1991年 | 103篇 |
1990年 | 74篇 |
1989年 | 148篇 |
1988年 | 111篇 |
1987年 | 147篇 |
1986年 | 125篇 |
1985年 | 152篇 |
1984年 | 77篇 |
1983年 | 80篇 |
1982年 | 60篇 |
1981年 | 45篇 |
1980年 | 66篇 |
1979年 | 73篇 |
1978年 | 64篇 |
1977年 | 48篇 |
1976年 | 48篇 |
1975年 | 44篇 |
1974年 | 27篇 |
1973年 | 31篇 |
1971年 | 24篇 |
排序方式: 共有5125条查询结果,搜索用时 15 毫秒
61.
62.
Identification of differentially expressed genes in aflatoxin B1- treated cultured primary rat hepatocytes and Fischer 344 rats 总被引:4,自引:1,他引:4
Harris AJ; Shaddock JG; Manjanatha MG; Lisenbey JA; Casciano DA 《Carcinogenesis》1998,19(8):1451-1458
Aflatoxin B1 (AFB1), a mutagen and hepatocarcinogen in rats and humans, is
a contaminant of the human food supply, particularly in parts of Africa and
Asia. AFB1-induced changes in gene expression may play a part in the
development of the toxic, immunosuppressive and carcinogenic properties of
this fungal metabolite. An understanding of the-role of AFB1 in modulating
gene regulation should provide insight regarding mechanisms of AFB1-induced
carcinogenesis. We used three PCR- based subtractive techniques to identify
AFB1-responsive genes in cultured primary rat hepatocyte RNA: differential
display PCR (DD-PCR), representational difference analysis (RDA) and
suppression subtractive hybridization (SSH). Each of the three techniques
identified AFB1- responsive genes, although no individual cDNA was isolated
by more than one technique. Nine cDNAs isolated using DD-PCR, RDA or SSH
were found to represent eight genes that are differentially expressed as a
result of AFB1 exposure. Genes whose mRNA levels were increased in cultured
primary rat hepatocytes after AFB1 treatment were corticosteroid binding
globulin (CBG), cytochrome P450 4F1 (CYP4F1), alpha-2 microglobulin,
C4b-binding protein (C4BP), serum amyloid A-2 and glutathione S-transferase
Yb2 (GST). Transferrin and a small CYP3A-like cDNA had reduced mRNA levels
after AFB1 exposure. Full-length CYP3A mRNA levels were increased. When
liver RNA from AFB1-treated male F344 rats was evaluated for transferrin,
CBG, GST, CYP3A and CYP4F1 expression, a decrease in transferrin mRNA and
an increase in CBG, GST, CYP3A and CYP4F1 mRNA levels was also seen.
Analysis of the potential function of these genes in maintaining cellular
homeostasis suggests that their differential expression could contribute to
the toxicity associated with AFB1 exposure.
相似文献
63.
目的:探讨输尿管硬镜在尿路疾病治疗中的应用效果。方法:对1000例尿路结石、输尿管及尿道狭窄、输尿管息肉、梗阻、异物存留等患者,均以输尿管硬镜配合其他设备进行治疗。结果:肾内结石34例治愈率76.5%,输尿管结石、膀胱及尿道结石治愈率为94.5%~99.8%;泌尿道狭窄治愈率66.7%~75%;33例泌尿道异物取出率97%。结论:基层医院在尿路疾病治疗中,根据病变的不同部位,将输尿管硬镜灵活配合现有并不高档的设备,同样可以取得较好的微创手术效果。 相似文献
64.
65.
66.
In the 50 years since the first edition of this journal, operative paediatric surgery has undergone radical change. Many of the most common instruments are unchanged, both as a testament to their utility and in recognition of past surgeons remembered eponymously. Surrounding that basic core of instruments, theatre has changed radically as new tools and techniques have arisen. Surgeons have come down from their pedestals, recognising surgery as a team sport rather than a solo performance. More than half of the current paediatric surgical trainees are women, a higher proportion than in any other craft group of the Royal Australasian College of Surgeons. The appearance, and rapid development, of laparoscopy is to many observers the most notable change in surgery over the last 50 years. Placed in its context though, it is simply the most prominent example of a frameshift in surgical thinking. The patient as a whole is now the focus, rather than just the disease. Recent developments are as much about minimising harm to normal tissues as they are about extirpating pathology. As a surgical maxim, ‘Primum non nocere’ is even more in evidence in 2015 than it was in 1965. 相似文献
67.
68.
69.
70.
Intra-arterial tissue adhesive for medical splenectomy in humans 总被引:2,自引:0,他引:2