全文获取类型
收费全文 | 30568篇 |
免费 | 2430篇 |
国内免费 | 69篇 |
专业分类
耳鼻咽喉 | 246篇 |
儿科学 | 1121篇 |
妇产科学 | 1030篇 |
基础医学 | 3809篇 |
口腔科学 | 501篇 |
临床医学 | 5332篇 |
内科学 | 5383篇 |
皮肤病学 | 449篇 |
神经病学 | 2984篇 |
特种医学 | 581篇 |
外科学 | 2469篇 |
综合类 | 427篇 |
一般理论 | 66篇 |
预防医学 | 4123篇 |
眼科学 | 369篇 |
药学 | 1686篇 |
中国医学 | 30篇 |
肿瘤学 | 2461篇 |
出版年
2023年 | 169篇 |
2022年 | 225篇 |
2021年 | 513篇 |
2020年 | 428篇 |
2019年 | 754篇 |
2018年 | 784篇 |
2017年 | 586篇 |
2016年 | 703篇 |
2015年 | 754篇 |
2014年 | 965篇 |
2013年 | 1505篇 |
2012年 | 2090篇 |
2011年 | 2116篇 |
2010年 | 1154篇 |
2009年 | 1053篇 |
2008年 | 1991篇 |
2007年 | 2118篇 |
2006年 | 2109篇 |
2005年 | 2011篇 |
2004年 | 1873篇 |
2003年 | 1824篇 |
2002年 | 1692篇 |
2001年 | 315篇 |
2000年 | 295篇 |
1999年 | 294篇 |
1998年 | 432篇 |
1997年 | 300篇 |
1996年 | 297篇 |
1995年 | 276篇 |
1994年 | 248篇 |
1993年 | 234篇 |
1992年 | 176篇 |
1991年 | 164篇 |
1990年 | 162篇 |
1989年 | 174篇 |
1988年 | 164篇 |
1987年 | 124篇 |
1986年 | 142篇 |
1985年 | 164篇 |
1984年 | 133篇 |
1983年 | 136篇 |
1982年 | 159篇 |
1981年 | 151篇 |
1980年 | 154篇 |
1979年 | 75篇 |
1978年 | 75篇 |
1977年 | 71篇 |
1976年 | 85篇 |
1975年 | 74篇 |
1974年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
The effect of a two day fast on maternal plasma volume and plasma protein concentration was explored in pregnant rats. Fasting between days 17 and 19 of gestation prevented the rise in plasma volume observed in ad libitum fed rats. Plasma protein concentration declined between day 17 and day 19 in both fasted and not fasted rats. Placental weight was not reduced by fasting during this stage of gestation. Fetal weight in the fasted group was 91% of the fetal weight of the ad libitum fed group. These results show that acute undernutrition, like longer term food or protein restriction, can prevent adequate plasma volume expansion and slow fetal growth. 相似文献
52.
53.
Belinda Joy Deal Rebecca A Fountain Carol Ann Russell-Broaddus Melinda Stanley-Hermanns 《Disaster Management & Response》2006,4(4):100-105
Hurricanes Katrina and Rita forced many individuals along the coast of Texas and Louisiana to seek shelter inland. Among the evacuees were residents with special needs and residents of nursing homes and group homes caring for mentally retarded and physically disabled persons. Many nurses volunteered to provide health care for those in need. This article discusses challenges and opportunities that were encountered by nurses volunteering in special-needs shelters. Issues related to human and physical resources, patient care, and confidentiality are discussed including lessons learned. As nurses who cared for evacuees in the shelter, it is hoped some of the lessons learned can be utilized in future disasters. 相似文献
54.
Invasion of oral epithelial cells by pathogenic oral bacteria may represent an important virulence factor in the progression of periodontal disease. Here we report that a clinical isolate of Prevotella intermedia, strain 17, was found to invade a human oral epithelial cell line (KB), whereas P. intermedia 27, another clinical isolate, and P. intermedia 25611, the type strain, were not found to invade the cell line. Invasion was quantified by the recovery of viable bacteria following a standard antibiotic protection assay and observed by electron microscopy. Cytochalasin D, cycloheximide, monodansylcadaverine, and low temperature (4°C) inhibited the internalization of P. intermedia 17. Antibodies raised against P. intermedia type C fimbriae and against whole cells inhibited invasion, but the anti-type-C-fimbria antibody inhibited invasion to a greater extent than the anti-whole-cell antibody. This work provides evidence that at least one strain of P. intermedia can invade an oral epithelial cell line and that the type C fimbriae and a cytoskeletal rearrangement are required for this invasion. 相似文献
55.
56.
57.
Ann E. Klasner MD Sharon R. Smith MD Michael W. Thompson BS Pharm Anthony J. Scalzo MD 《Academic emergency medicine》1998,5(10):992-996
Abstract. Objectives:To describe the outcomes of a mass carbon monoxide (CO) intoxication, and to calculate the CO half-life in a pediatric school-aged population.
Methods:A retrospective chart review was performed based on Regional Poison Center database information, hospital laboratory data, and medical records of the pediatric patients who sought care at one of 3 St. Louis area hospitals, after exposure to high levels of CO. Exposures occurred on January 5, 1996, after evidence of a CO leak was discovered at an area elementary school. Charts were reviewed for major demographics, symptoms reported, carboxyhemoglobin (COHb) levels and times, and level of effect.
Results:Information about 177 (35%) of the 504 children in attendance at school that day was available. Mean age was 8.7 ± 1.8 years (range 4–12 years). Symptoms were present in 155 (88%) of the 177 children for whom data were available. Initial COHb levels were obtained for 147 (83.1%) of the 177 children. First mean COHb level was 7.0% (95% CI = 6.6–7.5%). Second COHb level was obtained for 26 children with a mean of 2.7% (95% CI = 2.2–3.2%). Calculated half-life of COHb, on 100% 02 at 1 atm, was 44.0 minutes (95% CI = 39.6–48.2 minutes).
Conclusion:Some children had symptoms at COHb levels that traditionally have been considered nontoxic. The elimination of COHb was found to be more rapid in this population of children than reported in other studies. 相似文献
Methods:A retrospective chart review was performed based on Regional Poison Center database information, hospital laboratory data, and medical records of the pediatric patients who sought care at one of 3 St. Louis area hospitals, after exposure to high levels of CO. Exposures occurred on January 5, 1996, after evidence of a CO leak was discovered at an area elementary school. Charts were reviewed for major demographics, symptoms reported, carboxyhemoglobin (COHb) levels and times, and level of effect.
Results:Information about 177 (35%) of the 504 children in attendance at school that day was available. Mean age was 8.7 ± 1.8 years (range 4–12 years). Symptoms were present in 155 (88%) of the 177 children for whom data were available. Initial COHb levels were obtained for 147 (83.1%) of the 177 children. First mean COHb level was 7.0% (95% CI = 6.6–7.5%). Second COHb level was obtained for 26 children with a mean of 2.7% (95% CI = 2.2–3.2%). Calculated half-life of COHb, on 100% 0
Conclusion:Some children had symptoms at COHb levels that traditionally have been considered nontoxic. The elimination of COHb was found to be more rapid in this population of children than reported in other studies. 相似文献
58.
Christina M Marra Clare L Maxwell Ann C Collier Kevin R Robertson Allison Imrie 《BMC infectious diseases》2007,7(1):37
Background
Cerebrospinal fluid (CSF) pleocytosis may be seen in asymptomatic HIV-infected individuals. This finding complicates interpretation of CSF abnormalities when such individuals are evaluated for other central nervous system infections. The goal of this study was to determine the relationship between CSF pleocytosis, central nervous system (CNS) antiretroviral penetration, adherence to antiretroviral medication regimens, neurological symptoms and performance on neuropsychological tests. 相似文献59.
Anne Rannard Deborah Buck David E J Jones Oliver F W James Ann Jacoby 《Clinical gastroenterology and hepatology》2004,2(2):164-174
BACKGROUND AND AIMS: Assessment of health-related quality of life (HRQOL) is not routinely reported in the literature on chronic liver disease (CLD). Few studies have examined quality of life (QOL) in patients with primary biliary cirrhosis (PBC) despite its significant functional impact. One of the reasons for the lack of HRQOL measurement in patients with PBC may be the absence of a well-recognized and widely used measure that clinicians can use in ordinary clinical practice. The aim of this study is to evaluate HRQOL measures used in patients with PBC and examine the suitability of the measures for these patients. METHODS: A literature search identified reports that focused on any aspect of QOL in patients with PBC. Key texts were identified containing generic, domain-specific, and condition-specific measures. The identified measures were systematically evaluated for appropriateness, acceptability, reliability, validity, precision, and responsiveness. RESULTS: Twenty measures were identified from 9 key texts. Six of the measures were previously validated generic measures; 10 were domain-specific measures previously used to measure fatigue, depression, and psychological distress in general and psychiatric populations; and 4 measures had been developed in patients with CLD. Reporting of reliability and validity generally was consistent for all measures used. However, reporting of the remaining criteria was variable, particularly in relation to responsiveness over time and acceptability of the measures to patients with PBC. CONCLUSIONS: A clearer and more rigorous approach is needed in reporting the properties of HRQOL measures used in patients with PBC to help clinicians decide which measures are most suitable for these patients. 相似文献
60.