全文获取类型
收费全文 | 1875篇 |
免费 | 62篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 43篇 |
妇产科学 | 47篇 |
基础医学 | 209篇 |
口腔科学 | 24篇 |
临床医学 | 211篇 |
内科学 | 154篇 |
皮肤病学 | 12篇 |
神经病学 | 94篇 |
特种医学 | 115篇 |
外科学 | 131篇 |
综合类 | 50篇 |
预防医学 | 614篇 |
眼科学 | 11篇 |
药学 | 128篇 |
12篇 | |
中国医学 | 13篇 |
肿瘤学 | 71篇 |
出版年
2024年 | 4篇 |
2023年 | 89篇 |
2022年 | 116篇 |
2021年 | 125篇 |
2020年 | 120篇 |
2019年 | 46篇 |
2018年 | 50篇 |
2017年 | 55篇 |
2016年 | 69篇 |
2015年 | 96篇 |
2014年 | 112篇 |
2013年 | 162篇 |
2012年 | 63篇 |
2011年 | 57篇 |
2010年 | 115篇 |
2009年 | 103篇 |
2008年 | 44篇 |
2007年 | 49篇 |
2006年 | 64篇 |
2005年 | 21篇 |
2004年 | 17篇 |
2003年 | 20篇 |
2002年 | 32篇 |
2001年 | 26篇 |
2000年 | 22篇 |
1999年 | 40篇 |
1998年 | 26篇 |
1997年 | 19篇 |
1996年 | 22篇 |
1995年 | 24篇 |
1994年 | 16篇 |
1993年 | 19篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 22篇 |
1989年 | 15篇 |
1988年 | 6篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1942条查询结果,搜索用时 108 毫秒
1.
In forensic medicine, although various alcohols have been reported as indicators of decomposition in collected blood, no studies have examined short-chain fatty acids as indicators. In this study, the blood n-butyric acid concentration was quantified, and the association between n-butyric acid and decomposition was investigated to determine whether the detection of n-butyric acid could be a new indicator of decomposition. Among the forensic autopsies performed from 2016 to 2018 in our laboratory, the cases were divided into decomposed (n = 20) and non-decomposed (n = 20) groups based on macroscopic findings. Blood samples collected at the time of autopsy were derivatized with 3-nitrophenylhydrazine hydrochloride after solid-phase extraction. The n-butyric acid concentration was measured using liquid chromatography–tandem mass spectrometry. In addition, ethanol and n-propanol were measured using a gas chromatography-flame ionization detector. There was a significant difference (p < 0.01) in the concentrations of n-butyric acid between the decomposed and non-decomposed groups (0.343 ± 0.259 [0.030–0.973] and 0.003 ± 0.002 [0.001–0.007] mg/mL, respectively). In the decomposed group, n-butyric acid was detected at high concentrations, even in cases where n-propanol was low. These results suggest that n-butyric acid is more likely to be an indicator of blood decomposition than n-propanol. 相似文献
2.
3.
《Molecular immunology》2015,68(2):492-500
Although intranasal vaccination has been shown to be effective for the protection against inhalational anthrax, establishment of long-term immunity has yet to be achieved. Here, we investigated whether intranasal immunization with recombinant protective antigen (rPA) of Bacillus anthracis induces immunological memory responses in the mucosal and systemic compartments. Intranasal immunization with rPA plus cholera toxin (CT) sustained PA-specific antibody responses for 6 months in lung, nasal washes, and vaginal washes as well as serum. A significant induction of PA-specific memory B cells was observed in spleen, cervical lymph nodes (CLNs) and lung after booster immunization. Furthermore, intranasal immunization with rPA plus CT remarkably generated effector memory CD4+ T cells in the lung. PA-specific CD4+ T cells preferentially increased the expression of Th1- and Th17-type cytokines in lung, but not in spleen or CLNs. Collectively, the intranasal immunization with rPA plus CT promoted immunologic memory responses in the mucosal and systemic compartments, providing long-term immunity. 相似文献
4.
Heidi J Kalkwarf John A Shepherd Didier Hans Elena Gonzalez Rodriguez Joseph M Kindler Joan M Lappe Sharon Oberfield Karen K Winer Babette S Zemel 《Journal of bone and mineral research》2022,37(4):776-785
Trabecular bone score (TBS) is used for fracture prediction in adults, but its utility in children is limited by absence of appropriate reference values. We aimed to develop reference ranges for TBS by age, sex, and population ancestry for youth ages 5 to 20 years. We also investigated the association between height, body mass index (BMI), and TBS, agreement between TBS and lumbar spine areal bone mineral density (aBMD) and bone mineral apparent density (BMAD) Z-scores, tracking of TBS Z-scores over time, and precision of TBS measurements. We performed secondary analysis of spine dual-energy X-ray absorptiometry (DXA) scans from the Bone Mineral Density in Childhood Study (BMDCS), a mixed longitudinal cohort of healthy children (n = 2014) evaluated at five US centers. TBS was derived using a dedicated TBS algorithm accounting for tissue thickness rather than BMI. TBS increased only during ages corresponding to pubertal development with an earlier increase in females than males. There were no differences in TBS between African Americans and non-African Americans. We provide sex-specific TBS reference ranges and LMS values for calculation of TBS Z-scores by age and means and SD for calculation of Z-scores by pubertal stage. TBS Z-scores were positively associated with height Z-scores at some ages. TBS Z-scores explained only 27% and 17% of the variance of spine aBMD and BMAD Z-scores. Tracking of TBS Z-scores over 6 years was lower (r = 0.47) than for aBMD or BMAD Z-scores (r = 0.74 to 0.79), and precision error of TBS (2.87%) was greater than for aBMD (0.85%) and BMAD (1.22%). In sum, TBS Z-scores provide information distinct from spine aBMD and BMAD Z-scores. Our robust reference ranges for TBS in a well-characterized pediatric cohort and precision error estimates provide essential tools for clinical assessment using TBS and determination of its value in predicting bone fragility in childhood and adolescence. © 2022 American Society for Bone and Mineral Research (ASBMR). 相似文献
5.
6.
R. A. Wolfe F. B. LaPorte A. M. Rodgers E. C. Roys G. Fant A. B. Leichtman 《American journal of transplantation》2007,7(S1):1404-1411
Turndowns of offers of deceased donor kidneys for transplantation can contribute to inefficiencies in the organ distribution system and inequality in access to donated organs. Match run data were obtained for 4967 'good' kidneys placed and transplanted in 2005 after fewer than 50 offers. These kidneys were not recovered from donation after cardiac death or expanded criteria donors, or from donors with a history of substance abuse. On average, these good kidneys were not accepted until after seven offers to candidates and after offers to 2.4 programs. Models for the likelihood of acceptance found several donor and candidate characteristics to be significantly related to acceptance rates (p < 0.05). After accounting for these variables, there remained 2- to 3-fold differences among transplant programs in acceptance rates. These models could be used to identify kidney transplant centers with exceptional acceptance practices. Several strategies might be employed to increase acceptance rates for good organs. 相似文献
7.
8.
9.
10.