全文获取类型
收费全文 | 25038篇 |
免费 | 1526篇 |
国内免费 | 297篇 |
专业分类
耳鼻咽喉 | 516篇 |
儿科学 | 343篇 |
妇产科学 | 466篇 |
基础医学 | 4301篇 |
口腔科学 | 563篇 |
临床医学 | 2116篇 |
内科学 | 4825篇 |
皮肤病学 | 605篇 |
神经病学 | 1879篇 |
特种医学 | 1638篇 |
外科学 | 3225篇 |
综合类 | 185篇 |
现状与发展 | 3篇 |
一般理论 | 11篇 |
预防医学 | 1034篇 |
眼科学 | 685篇 |
药学 | 2070篇 |
中国医学 | 314篇 |
肿瘤学 | 2082篇 |
出版年
2023年 | 189篇 |
2022年 | 564篇 |
2021年 | 967篇 |
2020年 | 428篇 |
2019年 | 701篇 |
2018年 | 851篇 |
2017年 | 615篇 |
2016年 | 943篇 |
2015年 | 1285篇 |
2014年 | 1508篇 |
2013年 | 1624篇 |
2012年 | 2539篇 |
2011年 | 2239篇 |
2010年 | 1321篇 |
2009年 | 1114篇 |
2008年 | 1491篇 |
2007年 | 1450篇 |
2006年 | 1284篇 |
2005年 | 1034篇 |
2004年 | 831篇 |
2003年 | 782篇 |
2002年 | 695篇 |
2001年 | 443篇 |
2000年 | 385篇 |
1999年 | 252篇 |
1998年 | 132篇 |
1997年 | 93篇 |
1996年 | 79篇 |
1995年 | 52篇 |
1994年 | 50篇 |
1993年 | 44篇 |
1992年 | 78篇 |
1991年 | 80篇 |
1990年 | 66篇 |
1989年 | 75篇 |
1988年 | 60篇 |
1987年 | 74篇 |
1986年 | 57篇 |
1985年 | 32篇 |
1984年 | 23篇 |
1983年 | 34篇 |
1982年 | 19篇 |
1981年 | 29篇 |
1980年 | 17篇 |
1979年 | 27篇 |
1978年 | 25篇 |
1977年 | 17篇 |
1976年 | 16篇 |
1974年 | 22篇 |
1972年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
91.
92.
93.
Moon MK Kang DG Lee AS Yeom KB Kim JS Lee HS 《The American journal of Chinese medicine》2008,36(3):555-568
The present study was designed to investigate whether the aqueous extract of rhubarb (AR) could prevent the development of atherosclerosis through regulating vascular inflammatory processes in rats fed with an atherogenic diet. AR significantly reduced plasma low-density lipoprotein-cholesterol, and increased plasma high-density lipoprotein-cholesterol in rats fed with an atherogenic diet. AR inhibited vascular expressions of endothelin-1 (ET-1) and endothelin-converting enzyme (ECE) induced in rats with an atherogenic diet. On the other hand, AR augmented the vascular expression of endothelial nitric oxide synthase (ecNOS) and restored vascular nitric oxide (NO) production. Furthermore, AR suppressed the elevated expression of vascular nuclear factor-kappaB (NF-kappaB) p65 as well as adhesion molecules, including intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in rats fed with an atherogenic diet. Also, AR decreased endothelial expression of ICAM-1 and ET-1 in aorta. These results suggest that AR suppresses the development of atherosclerosis in the atherogenic-diet rat model through inhibiting vascular expressions of proinflammatory and adhesion molecules via the regulation of nitric oxide and endothelin system. 相似文献
94.
95.
Kang JH Farina A Park JH Kim SH Kim JY Rizzo N Elmakky A Jun HS Hahn WB Cha DH 《Prenatal diagnosis》2008,28(8):704-709
OBJECTIVES: To estimate the combined screening performance of first and early second trimester prenatal serum markers for Down syndrome, in screening for the development of preeclampsia, and analyze the correlation among marker levels, week of onset, and severity of the disease. METHODS: A retrospective cohort study was carried out on 32 women with preeclampsia and 3044 controls. Serum samples from these pregnancies were assayed for pregnancy-associated plasma protein-A (PAPP-A), alpha-fetoprotein (AFP), unconjugated estriol (uE3), human chorionic gonadotrophin (hCG), and inhibin-A. A likelihood ratio and the odds of being affected given a positive result (OAPR) of various combinations of markers were calculated and receiver operating characteristic (ROC) curves analysis was performed. RESULTS: In the pregnancies that subsequently developed preeclampsia, first trimester PAPP-A concentration was significantly lower and concentrations of early second trimester inhibin-A and hCG significantly elevated. Levels of early second trimester uE3 and AFP were not significantly altered. We also found that inhibin-A correlates with both onset of the disease and the severity. CONCLUSION: Down syndrome biochemical markers levels are altered in those patients who subsequently developed preeclampsia and may be a useful screening test for preeclampsia. Inhibin-A is the most predictive marker and correlates with the severity of subsequent preeclampsia and inversely with the week of occurrence of preeclampsia. 相似文献
96.
97.
Park IY Jo YS Shin JC Sung IK Kim M 《The journal of obstetrics and gynaecology research》2008,34(1):85-87
A 32-year-old woman at 17 weeks of gestation had a high possibility (1:82) of having a child with Down syndrome. Fetal chromosome according to amniocentesis revealed 46,XX,del(7)(q11.23q21.2). The fetus' chromosomal defect was not inherent because the chromosome analysis of the parents did not have any abnormal findings. We were regularly monitoring the pregnant woman by routine prenatal schedule and she had a normal spontaneous delivery. The baby showed a typical facial malformation, epicanthal fold, decreased muscle tone, and cardiac abnormalities. This is the first patient prenatally diagnosed with de novo 7q deletion by positive triple marker screening test. We consider the triple test, which is the most popular examination used to clarify the risk of chromosome abnormality in obstetrics, will be used not only for trisomy 21 and 18, but also for any other chromosome abnormalities. 相似文献
98.
99.
100.
Silicon-based anodes can increase the energy density of Li-ion batteries (LIBs) owing to their large weights and volumetric capacities. However, repeated charging and discharging can rapidly deteriorate the electrochemical properties because of a large volume change in the electrode. In this study, a commercial Fe-Si powder was coated with Al2O3 layers of different thicknesses via atomic layer deposition (ALD) to prevent the volume expansion of Si and suppress the formation of crack-induced solid electrolyte interfaces. The Al2O3 content was controlled by adjusting the trimethyl aluminum exposure time, and higher Al2O3 contents significantly improved the electrochemical properties. In 300 cycles, the capacity retention rate of a pouch full-cell containing the fabricated anodes increased from 69.8% to 72.3% and 79.1% depending on the Al2O3 content. The powder characterization and coin and pouch cell cycle evaluation results confirmed the formation of an Al2O3 layer on the powder surface. Furthermore, the expansion rate observed during the charging/discharging of the pouch cell indicated that the deposited layer suppressed the powder expansion and improved the cell stability. Thus, the performance of an LIB containing Si-alloy anodes can be improved by coating an ALD-synthesized protective Al2O3 layer. 相似文献