全文获取类型
收费全文 | 18549篇 |
免费 | 1394篇 |
国内免费 | 42篇 |
专业分类
耳鼻咽喉 | 170篇 |
儿科学 | 486篇 |
妇产科学 | 327篇 |
基础医学 | 2464篇 |
口腔科学 | 658篇 |
临床医学 | 1824篇 |
内科学 | 4272篇 |
皮肤病学 | 186篇 |
神经病学 | 1744篇 |
特种医学 | 717篇 |
外国民族医学 | 1篇 |
外科学 | 2297篇 |
综合类 | 388篇 |
一般理论 | 16篇 |
预防医学 | 1558篇 |
眼科学 | 516篇 |
药学 | 1306篇 |
中国医学 | 10篇 |
肿瘤学 | 1045篇 |
出版年
2022年 | 92篇 |
2021年 | 248篇 |
2020年 | 141篇 |
2019年 | 245篇 |
2018年 | 278篇 |
2017年 | 231篇 |
2016年 | 254篇 |
2015年 | 303篇 |
2014年 | 434篇 |
2013年 | 772篇 |
2012年 | 1024篇 |
2011年 | 1099篇 |
2010年 | 583篇 |
2009年 | 601篇 |
2008年 | 1100篇 |
2007年 | 1205篇 |
2006年 | 1226篇 |
2005年 | 1215篇 |
2004年 | 1134篇 |
2003年 | 1096篇 |
2002年 | 1106篇 |
2001年 | 268篇 |
2000年 | 255篇 |
1999年 | 256篇 |
1998年 | 277篇 |
1997年 | 245篇 |
1996年 | 216篇 |
1995年 | 226篇 |
1994年 | 185篇 |
1993年 | 172篇 |
1992年 | 204篇 |
1991年 | 176篇 |
1990年 | 209篇 |
1989年 | 154篇 |
1988年 | 197篇 |
1987年 | 183篇 |
1986年 | 167篇 |
1985年 | 182篇 |
1984年 | 168篇 |
1983年 | 146篇 |
1982年 | 197篇 |
1981年 | 197篇 |
1980年 | 152篇 |
1979年 | 130篇 |
1978年 | 102篇 |
1977年 | 88篇 |
1976年 | 75篇 |
1975年 | 69篇 |
1974年 | 86篇 |
1973年 | 68篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
The presence of depression was evaluated in a cross-section of 50 outpatients with dementia using the self-rated Geriatric Depression Scale and the clinician-rated Cornell Depression Scale. Impaired insight, as manifested by unawareness of dementia, correlated with dementia severity and discriminated a group of patients in whom the self-rated scale failed to show evidence of depression. Discrepancy between the two types of scales occurred among mildly as well as moderately demented patients when insight was impaired. Recognition of this discrepancy suggests that reliance on self-ratings may underestimate the presence and degree of depression among patients with dementia. 相似文献
52.
Levodopa improves physical fatigue in Parkinson's disease: a double-blind, placebo-controlled, crossover study. 总被引:1,自引:0,他引:1
Jau-Shin Lou Greg Kearns Theodore Benice Barry Oken Gary Sexton John Nutt 《Movement disorders》2003,18(10):1108-1114
We quantitatively investigated the effect of carbidopa/levodopa (25/100) on physical fatigue during finger tapping and force generation in a double-blind, placebo-controlled crossover study. Parkinson's disease (PD) subjects were randomly assigned to carbidopa/levodopa or placebo for Visit 1 or 2 and participated in the following two studies: (1) Finger tapping. Twenty-five PD patients used their index fingers to strike two keys 20 cm apart on a musical instrument digital interface (MIDI) keyboard. The slopes of the regression line of dwell time and movement time were used to assess the rate of fatigue development. (2) Force generation. Twelve PD patients contracted the wrist extensors maximally to obtain a baseline maximum voluntary contraction (BMVC) force. Then they repetitively contracted the wrist extensors at 50% of the BMVC for 7 seconds and rested for 3 seconds. An interval maximum voluntary contraction (IMVC) was measured every three repetitions. Fatigue was defined as an IMVC of less than 60% of the BMVC. The slope of the regression line of IMVC was used to assess the rate of force decline. These two studies were repeated 1 hour after carbidopa/levodopa (25/100) or placebo. Subjects filled out the Multidimensional Fatigue Inventory (MFI) at the beginning of the first visit. Results showed that the slope of dwell time decreased with levodopa but not with placebo (P = 0.004). The rate of force decline also decreased with levodopa but not with placebo (P = 0.01). The subscores in the dimension of physical fatigue in the MFI did not correlate with the rate changes in dwell time or the rate changes in force decline. We concluded that (1) levodopa improves physical fatigue in finger tapping and force generation, (2) physical fatigue in Parkinson's disease is at least partially related to dopamine deficiency, and (3) the MFI measures different aspects of physical fatigue compared with those measured by finger tapping and force generation. 相似文献
53.
The relationship of drinking and birth outcome in a US national sample of expectant mothers 总被引:3,自引:0,他引:3
Vivian B. Faden Barry I. Graubard & Mary Dufour 《Paediatric and perinatal epidemiology》1997,11(2):167-180
Alcohol consumption by pregnant women and birth outcome were studied in 9953 livebirths, 3309 fetal deaths and 5332 infant deaths from the 1988 National Maternal and Infant Health Survey. In crude analyses, race, age, mother's education, prenatal care, parity, low birthweight, gestational age, smoking and alcohol consumption during pregnancy were significantly related to the occurrence of fetal deaths and infant deaths. Among women having livebirths, race, age, mother's education, prenatal care, prematurity, gestational age, smoking and alcohol consumption during pregnancy were significantly related to having a low birthweight baby (< 2500 g). In this group, women who drank more during pregnancy also smoked more, were younger and less educated than women who drank at lower levels or not at all. The relationship of alcohol consumption during pregnancy and infant birthweight for those women having livebirths was studied using multivariable linear regression. The results indicated that race, mother's education, baby's sex, parity, mother's height, mother's body mass index and smoking, but not alcohol consumption, were significantly related to birthweight. Multivariable logistic regressions were performed for the occurrence of low birthweight, fetal death and infant death. The effect of alcohol was significant in all these analyses. These results indicate that alcohol has an important relationship with birth outcome, but that for the drinking reported in this study, the alcohol effect on mean birthweight is small relative to that of other risk factors, accounting for the non-significant result in the multiple linear regression. 相似文献
54.
55.
We describe a novel alpha-thalassaemia-1 deletion that removes the entire zeta-alpha globin gene cluster. A Chinese couple were referred for counselling after two consecutive pregnancies ended with fetal hydrops. Gene mapping was used to demonstrate that the mother is heterozygous for the South-east Asia alpha-thalassaemia-1 deletion (zeta zeta zeta alpha alpha/zeta zeta--SEA), while the father carries an alpha-thalassaemia-1 deletion of more than 100 kilobases (zeta zeta alpha alpha/----). This newly discovered deletion extends for unknown distances 3' and 5' of the zeta-alpha globin gene cluster and has been designated (--HW). 相似文献
56.
Barry Kirschbaum 《Artificial organs》1994,18(10):729-735
Abstract: Hypoalbuminemia among chronic hemodialysis patients is recognized as a poor prognostic sign. We observed that many of our chronic patients had a progressive decrease in their plasma albumin concentrations after they were converted to high flux, high efficiency dialysis from conventional dialysis mode. This change occurred in the absence of changes in the KTIV and protein catabolic rate (per) normalized to body mass. When nitrogen losses were measured, we found no difference in the dialysate concentrations of urea, alpha amino nitrogen, uric acid, or total nitrogen when high flux polysulfone was compared with high efficiency Cuprophan. While urea was the predominant nitrogen solute in all dialysate samples, there were some with a large gap between total and urea nitrogen. Alpha amino nitrogen losses, expressed as leucine equivalents, were substantial, ranging from 8. 4 to 9. 8 g/3. 5 h dialysis treatment. We believe that the increased losses of nitrogen experienced by patients after their conversion to a more efficient method of dialysis and not compensated for by a spontaneous increased intake of protein led to the observed fall in plasma albumin. Both urea and amino acid nitrogen losses need to be accounted for when achievement of higher KTIV dialysis is pursued. 相似文献
57.
John McMahon RMN BA Scottish Home Health Department Nursing Research Fellow Staff Nurse Barry T Jones BSc PhD Senior Lecturer 《Journal of advanced nursing》1992,17(2):173-186
Despite being constantly cited as a critical intervening variable in the recovery from alcohol problems, there is a paucity of literature on client motivation. This paper reviews the current literature which impacts on motivation and its importance in treatment and develops in a stepwise manner the revised expectancy/motivation hypothesis, tentatively explaining both motivation and denial as a natural process in behavioural change. Because of the revised expectancy/motivation hypothesis' distinctly defined stages which closely relate to the process of nursing and the qualitative and quantitative measurement it entails which the nursing process demands, it offers a particularly appropriate model for treatment within nurse practice. 相似文献
58.
H Dexter Barber John Lignelli Brian M Smith Barry K Bartee 《Journal of oral and maxillofacial surgery》2007,65(4):748-752
The most common types of barrier membranes used for bone or tissue regeneration are made of expanded-polytetrafluoroethylene (e-PTFE) or resorbable materials, such as collagen. Both the e-PTFE and resorbable membranes require primary soft tissue coverage. This article explores the use of a dense-polytetrafluoroethylene (d-PTFE) membrane, which does not require primary soft tissue coverage. The advantages of d-PTFE in contrast to the other more commonly used types of barrier membranes and the clinical significance of these advantages for implant surgical and restorative treatment are discussed. 相似文献
59.
60.