全文获取类型
收费全文 | 45981篇 |
免费 | 2082篇 |
国内免费 | 181篇 |
专业分类
耳鼻咽喉 | 93篇 |
儿科学 | 996篇 |
妇产科学 | 600篇 |
基础医学 | 2980篇 |
口腔科学 | 224篇 |
临床医学 | 5437篇 |
内科学 | 21361篇 |
皮肤病学 | 165篇 |
神经病学 | 1453篇 |
特种医学 | 1835篇 |
外科学 | 9234篇 |
综合类 | 493篇 |
预防医学 | 1278篇 |
眼科学 | 184篇 |
药学 | 961篇 |
2篇 | |
中国医学 | 49篇 |
肿瘤学 | 899篇 |
出版年
2024年 | 21篇 |
2023年 | 2446篇 |
2022年 | 3780篇 |
2021年 | 4428篇 |
2020年 | 3713篇 |
2019年 | 2338篇 |
2018年 | 2023篇 |
2017年 | 1772篇 |
2016年 | 1629篇 |
2015年 | 1677篇 |
2014年 | 3996篇 |
2013年 | 2785篇 |
2012年 | 1909篇 |
2011年 | 1542篇 |
2010年 | 2184篇 |
2009年 | 2199篇 |
2008年 | 1196篇 |
2007年 | 1183篇 |
2006年 | 1040篇 |
2005年 | 830篇 |
2004年 | 627篇 |
2003年 | 631篇 |
2002年 | 581篇 |
2001年 | 517篇 |
2000年 | 374篇 |
1999年 | 428篇 |
1998年 | 316篇 |
1997年 | 259篇 |
1996年 | 252篇 |
1995年 | 253篇 |
1994年 | 193篇 |
1993年 | 131篇 |
1992年 | 114篇 |
1991年 | 93篇 |
1990年 | 105篇 |
1989年 | 113篇 |
1988年 | 119篇 |
1987年 | 41篇 |
1985年 | 35篇 |
1984年 | 48篇 |
1983年 | 44篇 |
1982年 | 33篇 |
1981年 | 29篇 |
1980年 | 34篇 |
1979年 | 24篇 |
1978年 | 24篇 |
1976年 | 21篇 |
1975年 | 24篇 |
1974年 | 23篇 |
1973年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
104.
Beat-to-beat variability of ventricular repolarization (BVR) has been proposed as a strong predictor of Torsades de Pointes (TdP). BVR is also observed at the myocyte level, and a number of studies have shown the importance of calcium handling in influencing this parameter. The chronic AV block (CAVB) dog is a model of TdP arrhythmia in cardiac hypertrophy, and myocytes from these animals show extensive remodeling, including of Ca2 + handling. This remodeling process also leads to increased BVR. We aimed to determine the role that (local) Ca2 + handling plays in BVR.In isolated LV myocytes an exponential relationship was observed between BVR magnitude and action potential duration (APD) at baseline. Inhibition of Ca2 + release from sarcoplasmic reticulum (SR) with thapsigargin resulted in a reduction of [Ca2 +]i, and of both BVR and APD. Increasing ICaL in the presence of thapsigargin restored APD but BVR remained low. In contrast, increasing ICaL with preserved Ca2 + release increased both APD and BVR. Inhibition of Ca2 + release with caffeine, as with thapsigargin, reduced BVR despite maintained APD. Simultaneous inhibition of Na+/Ca2 + exchange and ICaL decreased APD and BVR to similar degrees, whilst increasing diastolic Ca2 +. Buffering of Ca2 + transients with BAPTA reduced BVR for a given APD to a greater extent than buffering with EGTA, suggesting subsarcolemmal Ca2 + transients modulated BVR to a larger extent than the cytosolic Ca2 + transient.In conclusion, BVR in hypertrophied dog myocytes, at any APD, is strongly dependent on SR Ca2 + release, which may act through modulation of the l-type Ca2 + current in a subsarcolemmal microdomain. 相似文献
105.
106.
107.
The effect of maternal antibodies on the cellular immune response after infant vaccination: A review
《Vaccine》2020,38(1):20-28
During the last few decades, maternal immunization as a strategy to protect young infants from infectious diseases has been increasingly recommended, yet some issues have emerged. Studies have shown that for several vaccines, such as live attenuated, toxoid and conjugated vaccines, high maternal antibody titers inhibit the infant’s humoral immune response after infant vaccination. However, it is not clear whether this decreased antibody titer has any clinical impact on the infant’s protection, as the cellular immune responses are often equally important in providing disease protection and may therefore compensate for diminished antibody levels. Reports describing the effect of maternal antibodies on the cellular immune response after infant vaccination are scarce, probably because such studies are expensive, labor intensive and utilize poorly standardized laboratory techniques. Therefore, this review aims to shed light on what is currently known about the cellular immune responses after infant vaccination in the presence of high (maternal) antibody titers both in animal and human studies. Overall, the findings suggest that maternally derived antibodies do not interfere with the cellular immune responses after infant vaccination. However, more research in humans is clearly needed, as most data originate from animal studies. 相似文献
108.
《Clinical nutrition (Edinburgh, Scotland)》2020,39(4):1264-1275
- Download : Download high-res image (110KB)
- Download : Download full-size image
109.
BackgroundThe objective of this study is to describe the recent trends and in-hospital outcomes with percutaneous pulmonic valve implantation (PPVI) and surgical pulmonic valve replacement (SPVR) in adult hospitals in the US after the availability of both the Melody valve (Medtronic Inc., Minneapolis, Minnesota) and the Sapien XT valve (Edwards Lifesciences, Irvine, CA).MethodsWe queried the National Inpatient Sample database (NIS) from January 2016 to December 2017 to identify hospitalizations for PPVI and SPVR.ResultsWe identified 5455 weighted discharges with PPVI and SPVR (PPVI=1140, SPVR=4305). PPVI procedures had increased in number over 2016 and 2017 (115 procedure at the first quarter of 2016, 195 procedures in the final quarter of 2017, P-trend=0.086), while SPVR volume remained constant. The incidence of in-hospital mortality was low with both procedures (SPRV: 1.6% vs. PPVI: 0.9%, p=0.071). SPVR had worse in-hospital outcomes, was associated with a longer length of stay [5 days vs. 1 day, p<0.001], and comparable cost of index hospitalization [$51,657 vs. $51,193] compared with PPVI.ConclusionAfter approval of the Sapien valve for commercial use in 2016, PPVI procedures have increased in frequency. PPVI is associated with lower procedural complications than SPVR, however, both carry a low risk of mortality. Despite the higher cost of the valves and delivery systems, PPVI is associated with a slightly lower cost of index hospitalization compared with SPVR, likely due to the higher in-hospital complications and LOS of the latter. 相似文献
110.