全文获取类型
收费全文 | 306930篇 |
免费 | 10279篇 |
国内免费 | 630篇 |
专业分类
耳鼻咽喉 | 2758篇 |
儿科学 | 9956篇 |
妇产科学 | 5402篇 |
基础医学 | 33397篇 |
口腔科学 | 4412篇 |
临床医学 | 25285篇 |
内科学 | 57847篇 |
皮肤病学 | 2390篇 |
神经病学 | 27956篇 |
特种医学 | 14101篇 |
外科学 | 49941篇 |
综合类 | 4210篇 |
现状与发展 | 1篇 |
一般理论 | 173篇 |
预防医学 | 30007篇 |
眼科学 | 5612篇 |
药学 | 18798篇 |
2篇 | |
中国医学 | 802篇 |
肿瘤学 | 24789篇 |
出版年
2023年 | 671篇 |
2022年 | 1049篇 |
2021年 | 2572篇 |
2020年 | 1468篇 |
2019年 | 2405篇 |
2018年 | 24468篇 |
2017年 | 19173篇 |
2016年 | 21354篇 |
2015年 | 3572篇 |
2014年 | 4762篇 |
2013年 | 6743篇 |
2012年 | 15588篇 |
2011年 | 29982篇 |
2010年 | 23614篇 |
2009年 | 16104篇 |
2008年 | 27424篇 |
2007年 | 30175篇 |
2006年 | 8998篇 |
2005年 | 10732篇 |
2004年 | 11594篇 |
2003年 | 12037篇 |
2002年 | 10043篇 |
2001年 | 1525篇 |
2000年 | 1438篇 |
1999年 | 1541篇 |
1998年 | 1812篇 |
1997年 | 1495篇 |
1996年 | 1330篇 |
1995年 | 1310篇 |
1994年 | 1118篇 |
1993年 | 1057篇 |
1992年 | 872篇 |
1991年 | 942篇 |
1990年 | 870篇 |
1989年 | 802篇 |
1988年 | 803篇 |
1987年 | 773篇 |
1986年 | 778篇 |
1985年 | 863篇 |
1984年 | 924篇 |
1983年 | 887篇 |
1982年 | 1154篇 |
1981年 | 1156篇 |
1980年 | 1003篇 |
1979年 | 633篇 |
1978年 | 675篇 |
1977年 | 600篇 |
1976年 | 527篇 |
1975年 | 473篇 |
1974年 | 490篇 |
排序方式: 共有10000条查询结果,搜索用时 2 毫秒
1.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
2.
James A. Akingbasote Alison J. Foster Ian Wilson Sunil Sarda Huw B. Jones J. Gerry Kenna 《Archives of toxicology》2016,90(4):853-862
Hepatic NADPH-cytochrome P450 oxidoreductase null (HRN?) mice exhibit normal hepatic and extrahepatic biotransformation enzyme activities when compared to wild-type (WT) mice, but express no functional hepatic cytochrome P450 activities. When incubated in vitro with [14C]-diclofenac, liver microsomes from WT mice exhibited extensive biotransformation to oxidative and glucuronide metabolites and covalent binding to proteins was also observed. In contrast, whereas glucuronide conjugates and a quinone-imine metabolite were formed when [14C]-diclofenac was incubated with HRN? mouse liver, only small quantities of P450-derived oxidative metabolites were produced in these samples and covalent binding to proteins was not observed. Livers from vehicle-treated HRN? mice exhibited enhanced lipid accumulation, bile duct proliferation, hepatocellular degeneration and necrosis and inflammatory cell infiltration, which were not present in livers from WT mice. Elevated liver-derived alanine aminotransferase, glutamate dehydrogenase and alkaline phosphatase activities were also observed in plasma from HRN? mice. When treated orally with diclofenac for 7 days, at 30 mg/kg/day, the severities of the abnormal liver histopathology and plasma liver enzyme findings in HRN? mice were reduced markedly. Oral diclofenac administration did not alter the liver histopathology or elevate plasma enzyme activities of WT mice. These findings indicate that HRN? mice are valuable for exploration of the role played by hepatic P450s in drug biotransformation, but poorly suited to investigations of drug-induced liver toxicity. Nevertheless, studies in HRN? mice could provide novel insights into the role played by inflammation in liver injury and may aid the evaluation of new strategies for its treatment. 相似文献
3.
4.
5.
6.
Marta Rozanski Valentin Neuhaus Emily Thornton Stéphanie J. E. Becker James P. Rathmell David Ring 《Journal of hand and microsurgery》2015,7(1):30-35
This study used the National Survey of Ambulatory Surgery (NSAS) database to measure the incidence of and risk factors for symptoms in the ambulatory surgery center and problems within 24 h after isolated carpal tunnel release (CTR). The NSAS contained records on 400,000 adult patients with carpal tunnel syndrome who were treated with CTR in 2006, based on ICD-9 codes. The type of anesthesia used and factors associated with symptoms and problems were sought in bivariate and multivariable statistical analyses. The mean duration of the procedure was 16 ± 8.8 min. Only 5 % were performed under local anesthesia without sedation, 45 % with IV sedation, 28 % regional anesthesia, and 19 % general anesthesia. Symptoms in the ambulatory surgery center or a problem within 24 h after discharge were recorded in 10 % of patients, all of them minor and transient, including difficulties with pain and its treatment. The strongest risk factors were male sex, age of 45 years and older, and participation of an anesthesiologist. Local anesthesia and regional anesthesia were associated with more perioperative symptoms and postoperative problems. Most CTR are performed with some sedation in the United States. CTR is a safe procedure: one in 10 patients will experience a minor issue in the perioperative or immediate postoperative period. 相似文献
7.
8.
9.
Richard Kim Elaine Tan Emily Wang Amit Mahipal Dung-Tsa Chen Biwei Cao Fadzai Masawi Cindy Machado James Yu Dae Won Kim 《The oncologist》2020,25(12):e1893-e1899
Lessons Learned
- The combination of trametinib and sorafenib has an acceptable safety profile, albeit at doses lower than approved for monotherapy.
- Maximum tolerated dose is trametinib 1.5 mg daily and sorafenib 200 mg twice daily.
- The limited anticancer activity observed in this unselected patient population does not support further exploration of trametinib plus sorafenib in patients with hepatocellular carcinoma.
10.