全文获取类型
收费全文 | 513篇 |
免费 | 18篇 |
国内免费 | 15篇 |
专业分类
儿科学 | 39篇 |
妇产科学 | 3篇 |
基础医学 | 36篇 |
口腔科学 | 6篇 |
临床医学 | 40篇 |
内科学 | 143篇 |
皮肤病学 | 6篇 |
神经病学 | 6篇 |
特种医学 | 128篇 |
外科学 | 23篇 |
综合类 | 47篇 |
预防医学 | 42篇 |
眼科学 | 1篇 |
药学 | 11篇 |
肿瘤学 | 15篇 |
出版年
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 5篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 14篇 |
2008年 | 6篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 15篇 |
2004年 | 8篇 |
2003年 | 13篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 13篇 |
1998年 | 26篇 |
1997年 | 40篇 |
1996年 | 51篇 |
1995年 | 25篇 |
1994年 | 26篇 |
1993年 | 25篇 |
1992年 | 9篇 |
1991年 | 13篇 |
1990年 | 10篇 |
1989年 | 23篇 |
1988年 | 19篇 |
1987年 | 15篇 |
1986年 | 21篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1981年 | 5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 |
1973年 | 1篇 |
排序方式: 共有546条查询结果,搜索用时 265 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.
C L Roberts C Morin D G Addiss S P Wahlquist P A Mshar J L Hadler 《Journal of clinical microbiology》1996,34(9):2292-2293
To describe patterns of testing for Cryptosporidium oocysts in stool samples, Connecticut laboratories were surveyed. Different detection methods were used. Most laboratories examined stools specifically for Cryptosporidium only on physician request. The rate of positive tests varted widely (0 to 28%). Higher rates of positivity were associated with the use of monoclonal antibody methods, the use of two or more staining procedures, and testing of stool specimens in addition to those requested by physicians. 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.
Mild measles and secondary vaccine failure during a sustained outbreak in a highly vaccinated population 总被引:10,自引:0,他引:10
A prolonged school-based outbreak of measles provided an opportunity to study "vaccine-modified" mild measles and secondary vaccine failure. Thirty-six (97%) of 37 unvaccinated patients had rash illnesses that met the Centers for Disease Control clinical case definition of measles, but 29 (15%) of 198 vaccinated patients did not, primarily because of low-grade or absent fever. Of 122 patients with seroconfirmed measles, 10 patients (all previously vaccinated) had no detectable measles-specific IgM and significantly milder illness than either vaccinated or unvaccinated patients with IgM-positive serum. Of 108 vaccinated patients with seroconfirmed measles, 17 patients (16%) had IgM-negative serology or rash illnesses that failed to meet the clinical case definition; their mean age (13 years), age at the time of vaccination, and time since vaccination did not differ from those of other vaccinated patients. The occurrence of secondary vaccine failure and vaccine-modified measles does not appear to be a major impediment to measles control in the United States but may lead to underreporting of measles cases and result in overestimation of vaccine efficacy in highly vaccinated populations. 相似文献