全文获取类型
收费全文 | 670篇 |
免费 | 51篇 |
国内免费 | 16篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 42篇 |
妇产科学 | 2篇 |
基础医学 | 63篇 |
口腔科学 | 9篇 |
临床医学 | 68篇 |
内科学 | 139篇 |
皮肤病学 | 6篇 |
神经病学 | 13篇 |
特种医学 | 229篇 |
外科学 | 59篇 |
综合类 | 32篇 |
预防医学 | 26篇 |
眼科学 | 4篇 |
药学 | 15篇 |
中国医学 | 1篇 |
肿瘤学 | 27篇 |
出版年
2021年 | 8篇 |
2020年 | 7篇 |
2018年 | 4篇 |
2017年 | 6篇 |
2016年 | 8篇 |
2015年 | 9篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 11篇 |
2011年 | 10篇 |
2010年 | 21篇 |
2009年 | 26篇 |
2008年 | 11篇 |
2007年 | 16篇 |
2006年 | 11篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 19篇 |
2002年 | 10篇 |
2001年 | 4篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 46篇 |
1997年 | 48篇 |
1996年 | 38篇 |
1995年 | 22篇 |
1994年 | 40篇 |
1993年 | 25篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 28篇 |
1988年 | 20篇 |
1987年 | 18篇 |
1986年 | 25篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 13篇 |
1981年 | 24篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1972年 | 3篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 6篇 |
排序方式: 共有737条查询结果,搜索用时 31 毫秒
101.
Acute renal rejection versus acute tubular necrosis in a canine model: MR evaluation 总被引:1,自引:0,他引:1
Findings of magnetic resonance (MR) imaging in acute renal rejection and acute tubular necrosis (ATN) were studied in dogs. On T1-weighted images, corticomedullary differentiation was absent in kidneys undergoing acute rejection. The loss of corticomedullary differentiation in these kidneys was secondary to a decrease in the relative signal intensity of the cortex, indicating prolongation of the T1 relaxation time of the cortex. In contrast, corticomedullary differentiation was preserved on T1-weighted images of autotransplanted kidneys and kidneys with ATN. MR imaging findings correlated with changes in water content in these three groups of kidneys. Kidneys undergoing acute rejection showed a marked increase in water content compared with kidneys in the other two groups. No change in fat content was found in any group. 相似文献
102.
103.
104.
Is ownership more important than the scientific credibility of audit protocols? A survey of medical audit advisory groups 总被引:1,自引:0,他引:1
BACKGROUND: It is commonly accepted that ownership is an important factor
in determining the acceptability and use of protocols or guidelines.
OBJECTIVES: We aimed to determine whether Medical Audit Advisory Groups
(MAAGs) are prepared to accept and use audit protocols developed
systematically by an external agency. METHOD: A postal questionnaire was
sent to all 105 MAAG chairmen in England and Wales to seek their views on
the external development of protocols, the inclusion of evidence-based
prioritized criteria, the general design of the protocols issued by the
Lilly Audit Centre and the numbers of practices reported by MAAGs as making
use of at least one of the first four protocols issued. RESULTS:
Ninety-five MAAGs (90%) responded. Of these, 86% were in favour of the
external development of protocols, and 98% and 94%, respectively, found
evidence-based and prioritized criteria valuable; 98% felt the overall
design and content of the Audit Centre protocols were excellent or good. A
total of 1018 practices was known to have made use of one of these
protocols, 261 taking part in multi-practice audits organized by their
MAAGs. CONCLUSION: Ownership is not necessarily more important than
scientific credibility and/or perceived utility. Externally developed audit
protocols containing evidence-based, prioritized review criteria are
acceptable to MAAGs, which are prepared to recommend their use in practice.
Accordingly, such systematically developed protocols offer a promising and
practical method for improving clinical effectiveness. Further research is
needed, however, to determine the comparative impact on standards of care
of protocols and other methods such as clinical guidelines.
相似文献
105.
Krimer LS; Herman MM; Saunders RC; Boyd JC; Hyde TM; Carter JM; Kleinman JE; Weinberger DR 《Cerebral cortex (New York, N.Y. : 1991)》1997,7(8):732-739
The entorhinal cortex (ERC) has been implicated in schizophrenia by a
number of studies. There is anatomical observation of neuronal heterotopias
in the rostral ERC, which is consistent with a hypothesis of
neurodevelopmental abnormalities in this disease. In view of the
significant cytoarchitectonic variation of the ERC throughout its
rostro-caudal extent, we performed a detailed subareal analysis of the
rostral two-thirds of the entorhinal cortex (ERCr) in 14 postmortem
schizophrenic brains and 14 matched controls (mean ages of 48 and 47
respectively). This systematic evaluation included both a qualitative
microscopic analysis of morphogenetic anomalies that would be consistent
with neurodevelopmental pathology and quantitative measurements of total
neuronal number, average neuronal density, laminar volume and laminar depth
from the cortical surface in cytoarchitectonically matched subareas of
schizophrenic and control brains. Parcellation of the entire ERC on the
basis of cytoarchitectonic criteria identified five distinct regions,
similar to those described in the macaque, except that in the human brain
three of the regions were further divisible into two or three subareas,
yielding nine distinct cellular compartments. Five rostral areas, prorhinal
(Pr), lateral (28L), intermediate rostral and caudal (281r and 281c), and
sulcal (28S), comprise the ERCr. Gross and microscopic examination of these
subdivisions throughout the ERCr failed to reveal laminar disorganization
in any of the schizophrenic brains. The brains also did not differ
significantly with respect to total neuronal number, total volume and
neuronal density per laminar and subareal subdivision, or laminar thickness
per entorhinal subarea. However, neuronal number and density were reduced
by 12-18% in Pr and 28L, suggesting that mild quantitative abnormalities
may exist in the ERCr and might possibly be revealed in a larger sample of
schizophrenic brains. We have failed to confirm previous reports of laminar
disorganization in the ERCr in brains of patients with schizophrenia; to
the extent that this region is implicated in schizophrenia, the structural
changes are likely to consist of more subtle cellular disturbances.
相似文献
106.
107.
108.
109.
110.
S Le P Langlois RC Vytialingam NA Aziz 《Journal of Medical Imaging and Radiation Oncology》1999,43(2):201-205
With increasing budgetary restraints on the health system, it is apparent that the main contribution that radiology departments can make to significant cost reduction in hospitals is to decrease the length of time between requesting an X-ray examination and receiving the report (and images). Digital radiography (DR) was introduced into the Radiology Department at the Royal Adelaide Hospital as a pilot project to research the cost–benefits and efficiency of the system, and to determine future directions for planning a digital department. The business plan developed prior to implementation of this pilot project predicted a saving of one bed-day per inpatient when a fully digital department with a picture archiving and communication system (PACS) is installed. This initial study comparing DR and conventional radiography (convR) provides baseline data and shows encouraging results for more rapid transmission of reports to clinicians. 相似文献