全文获取类型
收费全文 | 51603篇 |
免费 | 3599篇 |
国内免费 | 104篇 |
专业分类
耳鼻咽喉 | 388篇 |
儿科学 | 1907篇 |
妇产科学 | 1796篇 |
基础医学 | 6161篇 |
口腔科学 | 620篇 |
临床医学 | 8951篇 |
内科学 | 9401篇 |
皮肤病学 | 771篇 |
神经病学 | 4667篇 |
特种医学 | 1086篇 |
外国民族医学 | 33篇 |
外科学 | 4574篇 |
综合类 | 635篇 |
一般理论 | 79篇 |
预防医学 | 7186篇 |
眼科学 | 559篇 |
药学 | 2883篇 |
1篇 | |
中国医学 | 90篇 |
肿瘤学 | 3518篇 |
出版年
2023年 | 306篇 |
2022年 | 440篇 |
2021年 | 1001篇 |
2020年 | 679篇 |
2019年 | 1092篇 |
2018年 | 1244篇 |
2017年 | 859篇 |
2016年 | 977篇 |
2015年 | 1063篇 |
2014年 | 1466篇 |
2013年 | 2435篇 |
2012年 | 3494篇 |
2011年 | 3729篇 |
2010年 | 1973篇 |
2009年 | 1867篇 |
2008年 | 3287篇 |
2007年 | 3742篇 |
2006年 | 3586篇 |
2005年 | 3494篇 |
2004年 | 3370篇 |
2003年 | 3221篇 |
2002年 | 3027篇 |
2001年 | 425篇 |
2000年 | 310篇 |
1999年 | 436篇 |
1998年 | 662篇 |
1997年 | 527篇 |
1996年 | 454篇 |
1995年 | 374篇 |
1994年 | 383篇 |
1993年 | 376篇 |
1992年 | 298篇 |
1991年 | 269篇 |
1990年 | 261篇 |
1989年 | 219篇 |
1988年 | 213篇 |
1987年 | 232篇 |
1986年 | 199篇 |
1985年 | 221篇 |
1984年 | 229篇 |
1983年 | 232篇 |
1982年 | 281篇 |
1981年 | 256篇 |
1980年 | 205篇 |
1979年 | 152篇 |
1978年 | 131篇 |
1977年 | 150篇 |
1976年 | 127篇 |
1975年 | 108篇 |
1973年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
122.
123.
124.
125.
Amy S. Pikalow Mary E. Flynn Robert L. Searls 《Anatomical record (Hoboken, N.J. : 2007)》1994,238(3):407-414
Experiments were done to investigate the cause of the cranial (mesencephalic) flexure of the chick brain during stages 10 to 14. Measurements of the length and thickness of the roof and floor of the mesencephalon gave values similar to the values obtained previously by others. The labeling index was determined in the roof and floor of the prosencephalon, mesencephalon, and rhombencephalon as a preliminary measure of cell division. The labeling index was about the same in all regions, and was high enough to suggest that most of the cells were dividing. The labeling indices did not suggest that differential growth was caused by differential rates of cell division in the roof and floor of the mesencephalon. It was found through time lapse photography that the foregut and heart remained stationary along the rostrocaudal axis, whereas the prosencephalon moved rostrally and the mesencephalon underwent flexure. Measurements suggested that the neural tube cranial to the otic primordium grew in volume exponentially at a rate consistent with the labeling index. The rostral tip of the neural tube was observed to be linked to the rostral tip of the foregut by the ectoderm that formed Rathke's pouch at the neural tube and the pharyngeal membrane (prospective stomodeum) at the foregut. As the neural tube grew in length, the link between the neural tube and the foregut did not. We suggest that because of this link, the growing neural tube had to bend around the foregut, forming the cranial flexure, and the ectoderm folded where it attached to the prosencephalon, forming Rathke's pouch. © 1994 Wiley-Liss, Inc. 相似文献
126.
127.
128.
129.
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
130.
Pam Almada Karen Carafoli John B Flattery Douglas A French Mary McNamara 《Journal for nurses in staff development》2004,20(6):268-273
Newly graduated nurses often finish orientation and then believe they still need more support and mentoring than is available. Retention rates suffer as they think it must be better elsewhere. This article reports a community hospital's implementation of an education-based preceptor program. A convenience sample of 40 new graduates participated in the study. Qualitative and quantitative findings indicate a high level of satisfaction (mean visual analogue scale score 93.7), 29% increase in retention, and 9.5% decrease in vacancy. 相似文献