全文获取类型
收费全文 | 6520篇 |
免费 | 1031篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 49篇 |
儿科学 | 247篇 |
妇产科学 | 156篇 |
基础医学 | 944篇 |
口腔科学 | 150篇 |
临床医学 | 957篇 |
内科学 | 1147篇 |
皮肤病学 | 93篇 |
神经病学 | 801篇 |
特种医学 | 274篇 |
外国民族医学 | 1篇 |
外科学 | 684篇 |
综合类 | 516篇 |
一般理论 | 3篇 |
预防医学 | 507篇 |
眼科学 | 133篇 |
药学 | 609篇 |
中国医学 | 3篇 |
肿瘤学 | 302篇 |
出版年
2021年 | 75篇 |
2019年 | 77篇 |
2018年 | 105篇 |
2017年 | 74篇 |
2016年 | 78篇 |
2015年 | 103篇 |
2014年 | 150篇 |
2013年 | 231篇 |
2012年 | 263篇 |
2011年 | 288篇 |
2010年 | 160篇 |
2009年 | 143篇 |
2008年 | 226篇 |
2007年 | 268篇 |
2006年 | 259篇 |
2005年 | 282篇 |
2004年 | 254篇 |
2003年 | 249篇 |
2002年 | 250篇 |
2001年 | 214篇 |
2000年 | 222篇 |
1999年 | 208篇 |
1998年 | 126篇 |
1997年 | 95篇 |
1996年 | 100篇 |
1995年 | 89篇 |
1994年 | 83篇 |
1993年 | 87篇 |
1992年 | 153篇 |
1991年 | 168篇 |
1990年 | 139篇 |
1989年 | 178篇 |
1988年 | 137篇 |
1987年 | 194篇 |
1986年 | 146篇 |
1985年 | 136篇 |
1984年 | 123篇 |
1983年 | 110篇 |
1982年 | 89篇 |
1981年 | 96篇 |
1980年 | 108篇 |
1979年 | 103篇 |
1978年 | 67篇 |
1977年 | 71篇 |
1976年 | 58篇 |
1975年 | 59篇 |
1974年 | 69篇 |
1972年 | 70篇 |
1971年 | 49篇 |
1970年 | 51篇 |
排序方式: 共有7576条查询结果,搜索用时 0 毫秒
71.
72.
Standard methods of ventricular measurement with computed tomography (CT) and magnetic resonance imaging (MRI) allow for as much as a 10-mm variation in the level of the "best" axial slice through the lateral ventricles. In a series of 10 patients who received MRI scans, the effect of 1-mm variations in slice center level on measured ventricle-brain ratio (VBR) was determined; even variations as small as 1 mm can result in a 10% change in VBR. The amount of within-subject variability in VBR that could result from this factor alone appears to be more than twice as large as that encountered with direct volume measurements, indicating that the latter measure would be at least twice as sensitive to real changes in ventricular size as the VBR. 相似文献
73.
74.
A modified prognostic index based upon nutritional measurements 总被引:2,自引:0,他引:2
This paper describes a formula which, on solution, derives a prognostic index (PI) for predicting surgical complications using an anthropometric measurement and serum protein levels which may be obtained easily and rapidly. The formula was applied to three groups of patients, firstly 106 patients undergoing major surgical resection, secondly to 16 patients admitted for minor surgery to assess a normal range, and thirdly 10 patients undergoing total parenteral nutrition. In patients undergoing major surgical resection the prognostic index was significantly greater in those patients developing complications than in the control group and a good predictor of the risk of complications. The index uses nutritional measurements to predict complications rather than being a measurement of nutritional status and is therefore a poor monitor of the efficacy of nutritional therapy. 相似文献
75.
Mathematical/computational challenges in creating deformable and probabilistic atlases of the human brain 总被引:8,自引:0,他引:8
Striking variations in brain structure, especially in the gyral patterns of the human cortex, present fundamental challenges in human brain mapping. Probabilistic brain atlases, which encode information on structural and functional variability in large human populations, are powerful research tools with broad applications. Knowledge-based imaging algorithms can also leverage atlased information on anatomic variation. Applications include automated image labeling, pathology detection in individuals or groups, and investigating how regional anatomy is altered in disease, and with age, gender, handedness and other clinical or genetic factors. In this report, we illustrate some of the mathematical challenges involved in constructing population-based brain atlases. A disease-specific atlas is constructed to represent the human brain in Alzheimer's disease (AD). Specialized strategies are developed for population-based averaging of anatomy. Sets of high-dimensional elastic mappings, based on the principles of continuum mechanics, reconfigure the anatomy of a large number of subjects in an anatomic image database. These mappings generate a local encoding of anatomic variability and are used to create a crisp anatomical image template with highly resolved structures in their mean spatial location. Specialized approaches are also developed to average cortical topography. Since cortical patterns are altered in a variety of diseases, gyral pattern matching is used to encode the magnitude and principal directions of local cortical variation. In the resulting cortical templates, subtle features emerge. Regional asymmetries appear that are not apparent in individual anatomies. Population-based maps of cortical variation reveal a mosaic of variability patterns that segregate sharply according to functional specialization and cytoarchitectonic boundaries. 相似文献
76.
Woods I 《Minerva anestesiologica》2000,66(5):285-287
Mortality from high-risk surgery is close to 10% (20% with emergency). Poor outcome is linked to tissue hypoperfusion. Optimising fluid therapy has a good pathophysiological basis related to microvascular flow to the tissues and the risk of multiple organ failure. Metaanalysis showed the higher the risk of surgery the greater the benefit of fluid and flow optimisation. A direct technique (blood pressure is indirect) to manage fluid therapy measuring tissues perfusions has not yet fulfilled criteria (easiness, accuracy, less invasiveness). At present pulmonary artery catheter with continuous output measurement is the choice. The aim of the study is to assess the impact of fluid management to increase blood flow in high-risk surgical patient. 相似文献
77.
78.
A study was carried out to find out the effects of prior physical activity, sports participation and prior military training on the incidence of stress fractures among Gentlemen Cadets (GC''s) undergoing military training at Indian Military Academy (IMA). One thousand and fourteen GC''s were followed up for a period of 12 weeks. Thirty-seven GC''s developed stress fractures during the study period. The incidence of stress fractures was significantly higher in GC''s without any prior military training (p=0.0009). They were compared with 100 healthy controls drawn from the study population to study the influence of the other mentioned factors. There was no significant association between prior physical activity and stress fractures (OR=0.74, 95% CL=0.26 to 2.05, p=0.688). There was also no significant relationship between sports participation and stress fractures (OR=0.79. 95% CCL=0.35 to 1.81, p=0.684).KEY WORDS: Risk factors, Stress fractures 相似文献
79.
Margo N Woods 《Nutrition in clinical care》2005,8(1):24-30
Hypertriglyceridemia and insulin resistance have been seen in patients with HIV. Beneficial effects of the n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been reported for these conditions. One study of n-3 fatty acid supplementation in patients with HIV reported a decrease in serum triglyceride levels. These marine fatty acids appear to be working at a number of sites to achieve an improvement in lipid metabolism and insulin sensitivity. There is disagreement about the amount of n-3 fatty acids needed to achieve different effects and about the optimal ratio of dietary n-6 and n-3 fatty acids. 相似文献
80.
Speech and swallowing are important components of health‐related quality of life following head and neck cancer treatment. The aim of this study was to demonstrate the value of prospective multi‐centre evaluation by Speech and Language Therapists and to compare health‐related quality of life with speech and swallowing impairments. The University of Washington Head and Neck questionnaire version 4 (UW‐QOL) and Therapy Outcome Measures (TOM) were rated before and 6 months after cancer treatment in 95 patients from 12 centres. There was deterioration in TOM scores at 6 months. Pretreatment UW‐QOL swallowing was ranked equal first, with speech fourth. At 6 months speech was first and swallowing second. There were positive correlations between UW‐QOL swallowing and TOM dysphagia and between UW‐QOL speech and TOM laryngectomy, voice, phonology and dysarthria disorders. Both outcome measures are suitable for routine practice. Adaptation of TOM scales for use with head and neck cancer patients may improve sensitivity, validity and therapist compliance. 相似文献