全文获取类型
收费全文 | 5970篇 |
免费 | 345篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 170篇 |
妇产科学 | 143篇 |
基础医学 | 792篇 |
口腔科学 | 94篇 |
临床医学 | 359篇 |
内科学 | 1547篇 |
皮肤病学 | 191篇 |
神经病学 | 345篇 |
特种医学 | 218篇 |
外科学 | 1209篇 |
综合类 | 14篇 |
预防医学 | 138篇 |
眼科学 | 63篇 |
药学 | 261篇 |
中国医学 | 1篇 |
肿瘤学 | 776篇 |
出版年
2023年 | 57篇 |
2022年 | 104篇 |
2021年 | 162篇 |
2020年 | 71篇 |
2019年 | 97篇 |
2018年 | 139篇 |
2017年 | 117篇 |
2016年 | 144篇 |
2015年 | 175篇 |
2014年 | 174篇 |
2013年 | 230篇 |
2012年 | 387篇 |
2011年 | 417篇 |
2010年 | 210篇 |
2009年 | 207篇 |
2008年 | 391篇 |
2007年 | 367篇 |
2006年 | 428篇 |
2005年 | 363篇 |
2004年 | 391篇 |
2003年 | 378篇 |
2002年 | 379篇 |
2001年 | 80篇 |
2000年 | 58篇 |
1999年 | 78篇 |
1998年 | 88篇 |
1997年 | 76篇 |
1996年 | 70篇 |
1995年 | 56篇 |
1994年 | 61篇 |
1993年 | 54篇 |
1992年 | 37篇 |
1991年 | 48篇 |
1990年 | 38篇 |
1989年 | 28篇 |
1988年 | 22篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 8篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1981年 | 14篇 |
1980年 | 5篇 |
1979年 | 9篇 |
1978年 | 11篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1973年 | 8篇 |
排序方式: 共有6341条查询结果,搜索用时 156 毫秒
91.
Purpose: To assess the associations of the natural environment with obesity and physical activity in nonmetropolitan areas of the United States among representative samples by using 2 indices of outdoor activity potential (OAP) at the county level. Methods: We used the data from 457,820 and 473,296 noninstitutionalized adults aged over 18 years for obesity and physical activity, respectively, from the 2000‐2006 Behavioral Risk Factor Surveillance System. The OAP indices were (1) a recreational opportunity index based on 24 variables related to outdoor physical activity, such as the number of facilities available for walking, biking, hiking, and swimming derived from the 1997 National Outdoor Recreation Supply Information System; and (2) a natural amenities index which was based on physical and social environmental characteristics, such as climate, topographic relief, land cover, and tourism. We fitted logistic regression models using generalized estimating equations to control for county level intracorrelation and tested each index separately to assess its relationship with obesity and physical activity. Findings: Recreational opportunities were higher in areas with greater natural amenities. After controlling for individual‐level socioeconomic and demographic characteristics, the prevalence of obesity decreased and propensity for physical activity increased with increasing levels of both recreational opportunities and natural amenities. Conclusions: Multiple indices of OAP based on characteristics of the built, natural and social environments were associated with decreased obesity and increased physical activity in nonmetropolitan areas. Public health interventions should consider the opportunities and limitations offered by the natural environment for promoting physical activity and reducing obesity in rural areas. 相似文献
92.
Kuniya Honda Masamichi Shinoda Akihiko Furukawa Kozue Kita Noboru Noma Koichi Iwata 《European journal of oral sciences》2014,122(6):391-396
Orofacial cold hyperalgesia is known to cause severe persistent pain in the face following trigeminal nerve injury or inflammation, and transient receptor potential (TRP) vanilloid 1 (TRPV1) and TRP ankylin 1 (TRPA1) are thought to be involved in cold hyperalgesia. However, how these two receptors are involved in cold hyperalgesia is not fully understood. To clarify the mechanisms underlying facial cold hyperalgesia, nocifensive behaviors to cold stimulation, the expression of TRPV1 and TRPA1 in trigeminal ganglion (TG) neurons, and TG neuronal excitability to cold stimulation following facial capsaicin injection were examined in rats. The head‐withdrawal reflex threshold (HWRT) to cold stimulation of the lateral facial skin was significantly decreased following facial capsaicin injection. This reduction of HWRT was significantly recovered following local injection of TRPV1 antagonist as well as TRPA1 antagonist. Approximately 30% of TG neurons innervating the lateral facial skin expressed both TRPV1 and TRPA1, and about 64% of TRPA1‐positive neurons also expressed TRPV1. The TG neuronal excitability to noxious cold stimulation was significantly increased following facial capsaicin injection and this increase was recovered by pretreatment with TRPA1 antagonist. These findings suggest that TRPA1 sensitization via TRPV1 signaling in TG neurons is involved in cold hyperalgesia following facial skin capsaicin injection. 相似文献
93.
94.
95.
Hidenao Kayawake Toyofumi F. Chen-Yoshikawa Masao Saito Hiroya Yamagishi Akihiko Yoshizawa Shin-ich Hirano Ryosuke Kurokawa Hiroshi Date 《The Annals of thoracic surgery》2021,111(1):246-252
- Download : Download high-res image (212KB)
- Download : Download full-size image
96.
Mai Shimura Hiroshi Ishikawa Hiromi Nagase Akihiko Mochizuki Futoshi Sekiguchi Naho Koshimizu Toshiyuki Itai Mizuha Odagami 《Congenital anomalies》2018,58(5):167-170
We investigated whether it was possible to predict the prognosis of fetuses with cystic hygroma in early pregnancy based on the degree of neck thickening. We retrospectively analyzed 57 singleton pregnancies with fetuses with cystic hygroma who were examined before the 22nd week of pregnancy. The fetuses were categorized according to the outcome, structural abnormalities at birth, and chromosomal abnormalities. Here, we proposed a new sonographic predictor with which we assessed neck thickening by dividing the width of the neck thickening by the biparietal diameter, which is expressed as the cystic hygroma width/biparietal diameter ratio. The median cystic hygroma width/biparietal diameter ratio in the intrauterine fetal death group (0.51) was significantly higher than that in the live birth group (0.27). No significant difference in the median cystic hygroma width/biparietal diameter ratio was found between the structural abnormalities group at birth and the no structural abnormalities group, and no significant difference in the median cystic hygroma width/biparietal diameter ratio was found between the chromosomal abnormality group and the no chromosomal abnormality group. We used receiver operating characteristic analysis to evaluate the cystic hygroma width/biparietal diameter ratio to predict intrauterine fetal death. When the cystic hygroma width/biparietal diameter ratio cut‐off value was 0.5, intrauterine fetal death could be predicted with a sensitivity of 52.9% and a specificity of 100%. It is possible to predict intrauterine fetal death in fetuses with cystic hygroma in early pregnancy if cystic hygroma width/biparietal diameter ratio is measured. However, even if cystic hygroma width/biparietal diameter ratio is measured, predicting the presence or absence of a structural abnormality at birth or a chromosomal abnormality is difficult. 相似文献
97.
98.
99.
100.