全文获取类型
收费全文 | 1714篇 |
免费 | 133篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 114篇 |
妇产科学 | 31篇 |
基础医学 | 208篇 |
口腔科学 | 28篇 |
临床医学 | 191篇 |
内科学 | 287篇 |
皮肤病学 | 21篇 |
神经病学 | 78篇 |
特种医学 | 333篇 |
外科学 | 170篇 |
综合类 | 12篇 |
预防医学 | 130篇 |
眼科学 | 10篇 |
药学 | 111篇 |
中国医学 | 1篇 |
肿瘤学 | 131篇 |
出版年
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 21篇 |
2020年 | 14篇 |
2019年 | 19篇 |
2018年 | 36篇 |
2017年 | 11篇 |
2016年 | 19篇 |
2015年 | 36篇 |
2014年 | 35篇 |
2013年 | 46篇 |
2012年 | 43篇 |
2011年 | 51篇 |
2010年 | 53篇 |
2009年 | 40篇 |
2008年 | 30篇 |
2007年 | 66篇 |
2006年 | 45篇 |
2005年 | 55篇 |
2004年 | 40篇 |
2003年 | 25篇 |
2002年 | 39篇 |
2001年 | 31篇 |
2000年 | 30篇 |
1999年 | 45篇 |
1998年 | 109篇 |
1997年 | 82篇 |
1996年 | 80篇 |
1995年 | 64篇 |
1994年 | 58篇 |
1993年 | 69篇 |
1992年 | 28篇 |
1991年 | 18篇 |
1990年 | 29篇 |
1989年 | 51篇 |
1988年 | 37篇 |
1987年 | 48篇 |
1986年 | 39篇 |
1985年 | 35篇 |
1984年 | 30篇 |
1983年 | 20篇 |
1982年 | 28篇 |
1981年 | 27篇 |
1980年 | 32篇 |
1979年 | 15篇 |
1978年 | 23篇 |
1977年 | 24篇 |
1976年 | 25篇 |
1975年 | 15篇 |
1974年 | 6篇 |
排序方式: 共有1858条查询结果,搜索用时 15 毫秒
1.
Needle-localized breast biopsy: why do we fail? 总被引:10,自引:0,他引:10
2.
Ketai LH; Williamson MR; Telepak RJ; Levy H; Koster FT; Nolte KB; Allen SE 《Radiology》1994,191(3):665
3.
4.
Eain M. Cornford Deborah Young James W. Paxton 《Cancer chemotherapy and pharmacology》1992,29(6):439-444
Summary The blood-brain barrier penetration of amsacrine and its analogs 9-({2-methoxy-4-[(methylsulfonyl)-amino]phenyl}amino)-,5-dimethyl-4-acridine carboxamide (CI-921) and M-[2-(dimethylamino)ethyl]-acridine-4-carboxamide (AC) was measured in the barbiturate-anesthetized mouse. After intracarotid administration, AC was almost completery extracted (90%) in a single transit through the brain capillaries, whereas CI-921 (20%) and amsacrine (15%) were moderately extracted. AC is retained in the brain; no loss of AC from the brain was apparent at 1, 2, 4, or 8 min after injection. In contrast, after intraportal administration, 75% of the AC, 94% of the CI-921, and 57% of the amsacrine was extracted in a single transit through the hepatic vasculature. Rather than being retained in the mouse liver, these acridine antitumor agents show time-dependent loss (t
1/2=10 min for amsacrine and AC, 24 min for CI-921). We conclude that unlike most antitumor agents, these acridine drugs appear to penetrate the blood-brain barrier readily.This study was supported by the Auckland Medical Research Foundation (New Zealand), by the Medical Research Foundation (New Zealand), by the National Science Foundation (United States/New Zealand Cooperative Science Program), by the United States Veterans Administration, and by NIH grant NS 25554 相似文献
5.
荧光原位杂交技术分析人结肠菌群方法研究 总被引:2,自引:0,他引:2
建立荧光原位杂交技术分析人体内结肠菌群的方法。取受试者新鲜粪便 ,选用 5种特异性的 16SrRNA寡核苷酸探针 ,检测粪便样本收集后的保存时间、温度 ,离心条件及样本固定液存放时间对杂交计数结果的影响。结果建立最佳实验条件为 :粪便样本收集后应尽快在 4℃下保存 ,放置时间不要超过 12小时即作处理 ;样本的适宜离心条件为 70 0g 2分钟 ;样本用多聚甲醛固定后在 - 80℃下存放时间不要超过 5个月。该方法具有较好的稳定性 ,可以有效地检出个体之间结肠菌群的差异。 相似文献
6.
Christian J Streck Paxton V Dickson Catherine Y C Ng Junfang Zhou John T Gray Amit C Nathwani Andrew M Davidoff 《Clinical cancer research》2005,11(16):6020-6029
PURPOSE: Type I IFNs (IFN-alpha/beta) have shown significant antitumor activity in preclinical models but limited efficacy and significant toxicity in clinical trials. We hypothesized that the antitumor activity of type I IFNs could be enhanced by chronic, low-dose systemic delivery and sought to test this in murine neuroblastoma models. EXPERIMENTAL DESIGN: Continuous liver-generated expression of human IFN-beta (hINF-beta) was achieved through a gene therapy-mediated approach using adeno-associated virus vectors encoding hIFN-beta (AAV hINF-beta). Orthotopic localized retroperitoneal and disseminated models of neuroblastoma were established using three different xenografts. Immunohistochemical analysis and ELISA were used to evaluate the antiangiogenic effect of therapy. RESULTS: The development of both localized orthotopic (retroperitoneal) and disseminated neuroblastoma was prevented in all mice expressing hINF-beta. Continued growth of established retroperitoneal tumors, treated with AAV hINF-beta as monotherapy, was significantly restricted, and survival for mice with established, disseminated disease was significantly prolonged following administration of AAV hINF-beta. Analysis of treated tumors revealed a significant antiangiogenic effect. Mean intratumoral vessel density was diminished and expression of the angiogenic factors vascular endothelial growth factor and basic fibroblast growth factor were both decreased. Finally, combination therapy in which AAV hIFN-beta was used together with low-dose cyclophosphamide resulted in regression of both established retroperitoneal and disseminated disease. CONCLUSIONS: AAV-mediated delivery of hIFN-beta when used as monotherapy was able to restrict neuroblastoma growth due in part to inhibition of angiogenesis. When used in combination with conventional chemotherapy, AAV hIFN-beta was able to effect complete tumor regression. 相似文献
7.
8.
9.
10.