全文获取类型
收费全文 | 569篇 |
免费 | 23篇 |
国内免费 | 15篇 |
专业分类
儿科学 | 39篇 |
妇产科学 | 4篇 |
基础医学 | 42篇 |
口腔科学 | 6篇 |
临床医学 | 46篇 |
内科学 | 162篇 |
皮肤病学 | 4篇 |
神经病学 | 35篇 |
特种医学 | 136篇 |
外科学 | 27篇 |
综合类 | 45篇 |
预防医学 | 29篇 |
药学 | 16篇 |
肿瘤学 | 16篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 8篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 12篇 |
2012年 | 15篇 |
2011年 | 15篇 |
2010年 | 15篇 |
2009年 | 16篇 |
2008年 | 18篇 |
2007年 | 27篇 |
2006年 | 20篇 |
2005年 | 16篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 26篇 |
1997年 | 39篇 |
1996年 | 46篇 |
1995年 | 24篇 |
1994年 | 25篇 |
1993年 | 26篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 14篇 |
1986年 | 21篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 8篇 |
1979年 | 2篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1975年 | 6篇 |
1968年 | 1篇 |
排序方式: 共有607条查询结果,搜索用时 250 毫秒
1.
2.
3.
4.
5.
Low-artifact intravascular devices: MR imaging evaluation 总被引:2,自引:0,他引:2
Teitelbaum GP; Ortega HV; Vinitski S; Stern H; Tsuruda JS; Mitchell DG; Rifkin MD; Bradley WG Jr 《Radiology》1988,168(3):713-719
Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible. 相似文献
6.
Variability of skin temperature in the waking monkey 总被引:3,自引:0,他引:3
7.
Effect of dosage on immunogenicity of a Vi conjugate vaccine injected twice into 2- to 5-year-old Vietnamese children 总被引:2,自引:0,他引:2 下载免费PDF全文
Canh DG Lin FY Thiem VD Trach DD Trong ND Mao ND Hunt S Schneerson R Robbins JB Chu C Shiloach J Bryla DA Bonnet MC Schulz D Szu SC 《Infection and immunity》2004,72(11):6586-6588
In a double-blind, randomized, and placebo-controlled previous trial, the efficacy of Vi-rEPA for typhoid fever in 2- to 5-year-olds was 89.0% for 46 months. Vi-rEPA contained 25 microg of Vi and induced a greater-than-eightfold rise in immunoglobulin G (IgG) anti-Vi in all of the vaccinees tested. In this investigation, we conducted a dosage-immunogenicity study of 5, 12.5, and 25 microg of Vi-rEPA in this age group. Two doses of Vi-rEPA were injected 6 weeks apart. Blood samples were taken before and at 10 weeks (4 weeks after the second injection) and 1 year later. All postimmunization geometric mean (GM) levels were higher than the preimmune levels (P < 0.0001). At 10 weeks, the GM IgG anti-Vi level elicited by 25 microg (102 EU/ml) was higher than those elicited by 12.5 microg (74.7 EU/ml) and 5 microg (43 EU/ml) (P < 0.004): all of the children had > or = 3.52 EU/ml (estimated minimum protective level). One year later, the levels declined about sevenfold (13.3 and 11.3 versus 6.43 EU/ml, P < 0.0001) but remained significantly higher than the preimmune levels (P < 0.0001), and >96% of the children had a greater-than-eightfold rise. This study also confirmed the safety and consistent immunogenicity of the four lots of Vi-rEPA used in this and previous trials. 相似文献
8.
Rao VM; Dalinka MK; Mitchell DG; Spritzer CE; Kaplan F; August CS; Axel L; Kressel HY 《Radiology》1986,161(1):217-220
Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements. 相似文献
9.
10.
André Beate Canhão Helena Espnes Geir A. Rodrigues Ana Maria Ferreira Gregorio Maria Joao Nguyen Camilla Sousa Rute Grønning Kjersti 《Zeitschrift fur Gesundheitswissenschaften》2021,29(6):1373-1378
Journal of Public Health - Adolescents’ sleep duration has decreased over the past century; this is mainly caused by problems with falling asleep. Short sleep duration, poor sleep quality,... 相似文献