全文获取类型
收费全文 | 3220篇 |
免费 | 199篇 |
国内免费 | 117篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 132篇 |
妇产科学 | 57篇 |
基础医学 | 388篇 |
口腔科学 | 251篇 |
临床医学 | 288篇 |
内科学 | 663篇 |
皮肤病学 | 61篇 |
神经病学 | 287篇 |
特种医学 | 413篇 |
外国民族医学 | 1篇 |
外科学 | 255篇 |
综合类 | 42篇 |
一般理论 | 3篇 |
预防医学 | 260篇 |
眼科学 | 38篇 |
药学 | 260篇 |
中国医学 | 20篇 |
肿瘤学 | 96篇 |
出版年
2023年 | 28篇 |
2022年 | 36篇 |
2021年 | 73篇 |
2020年 | 55篇 |
2019年 | 76篇 |
2018年 | 86篇 |
2017年 | 66篇 |
2016年 | 78篇 |
2015年 | 73篇 |
2014年 | 116篇 |
2013年 | 132篇 |
2012年 | 166篇 |
2011年 | 198篇 |
2010年 | 146篇 |
2009年 | 136篇 |
2008年 | 155篇 |
2007年 | 185篇 |
2006年 | 123篇 |
2005年 | 129篇 |
2004年 | 86篇 |
2003年 | 68篇 |
2002年 | 53篇 |
2001年 | 47篇 |
2000年 | 47篇 |
1999年 | 50篇 |
1998年 | 98篇 |
1997年 | 100篇 |
1996年 | 109篇 |
1995年 | 71篇 |
1994年 | 69篇 |
1993年 | 74篇 |
1992年 | 22篇 |
1991年 | 40篇 |
1990年 | 29篇 |
1989年 | 62篇 |
1988年 | 44篇 |
1987年 | 58篇 |
1986年 | 41篇 |
1985年 | 55篇 |
1984年 | 28篇 |
1983年 | 22篇 |
1982年 | 31篇 |
1981年 | 25篇 |
1980年 | 33篇 |
1979年 | 11篇 |
1978年 | 17篇 |
1977年 | 18篇 |
1976年 | 28篇 |
1975年 | 16篇 |
1967年 | 6篇 |
排序方式: 共有3536条查询结果,搜索用时 15 毫秒
1.
2.
Talita da Silva Mendes de Farias Ariclécio Cunha de Oliveira Sandra Andreotti Fernanda Gaspar do Amaral Patrícia Chimin André Ricardo Alves de Proença Francisco Leonardo Torres Leal Rogério Antonio Laurato Sertié Amanda Baron Campana Andressa Bolsoni Lopes Arnaldo Henrique de Souza José Cipolla‐Neto Fabio Bessa Lima 《Journal of pineal research》2015,58(3):251-261
Melatonin, the main hormone produced by the pineal gland, is secreted in a circadian manner (24‐hr period), and its oscillation influences several circadian biological rhythms, such as the regulation of clock genes expression (chronobiotic effect) and the modulation of several endocrine functions in peripheral tissues. Assuming that the circadian synchronization of clock genes can play a role in the regulation of energy metabolism and it is influenced by melatonin, our study was designed to assess possible alterations as a consequence of melatonin absence on the circadian expression of clock genes in the epididymal adipose tissue of male Wistar rats and the possible metabolic repercussions to this tissue. Our data show that pinealectomy indeed has impacts on molecular events: it abolishes the daily pattern of the expression of Clock, Per2, and Cry1 clock genes and Pparγ expression, significantly increases the amplitude of daily expression of Rev‐erbα, and affects the pattern of and impairs adipokine production, leading to a decrease in leptin levels. However, regarding some metabolic aspects of adipocyte functions, such as its ability to synthesize triacylglycerols from glucose along 24 hr, was not compromised by pinealectomy, although the daily profile of the lipogenic enzymes expression (ATP‐citrate lyase, malic enzyme, fatty acid synthase, and glucose‐6‐phosphate dehydrogenase) was abolished in pinealectomized animals. 相似文献
3.
4.
de Oliveira Adilson J M Solla Davi J. F. de Oliveira Klever F. Amaral Bruno S. Andrade Almir F. Kolias Angelos G. Paiva Wellingson S. 《Neurological sciences》2022,43(1):427-434
Neurological Sciences - Chronic subdural haematoma (CSDH) is one of the most common neurosurgical pathologies. The recurrence of chronic subdural haematomas is an important concern, considering... 相似文献
5.
Béla Nagy Zsolt Bene Zsolt Fejes Sonya L. Heltshe David Reid Nicola J. Ronan Yvonne McCarthy Daniel Smith Attila Nagy Elizabeth Joseloff György Balla János Kappelmayer Milan Macek Scott C. Bell Barry J. Plant Margarida D. Amaral István Balogh 《Journal of cystic fibrosis》2019,18(2):271-277
Background
We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.Methods
In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).Results
After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).Conclusions
This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy. 相似文献6.
Paulo Cezar Galv?o do Amaral Euler de Medeiros ázaro Filho Thales Delmondes Galv?o Ettinger Eric Junior Galeno Egydio José de Magalh?es Neto Fabrício Mascarenhas Edvaldo Fahel 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2006,10(3):355-358
BACKGROUND: Randomized studies demonstrate that laparoscopic appendectomy yields better results compared with open techniques. We sought to identify factors that determine an extended hospital stay among patients undergoing laparoscopic appendectomy. METHODS: This was a prospective study including 669 patients undergoing laparoscopic appendectomy. We analyzed variables that can predict the length of hospital stay. RESULTS: Of 669 patients undergoing laparoscopic appendectomy, 141 stayed in the hospital for > or = 5 days (Group 1), and 97 stayed in the hospital for < or = 1 day after surgery (Group 2). The univariate analysis demonstrated that fever (P<0.0001), nausea and vomiting (P=0.060), leukocytosis (P<0.0001), gangrened or perforated intraoperative appearance of the appendix (P<0.0001), and appendix position behind the ileocecal junction (P<0.001) were related to a longer hospital stay. The multivariate analysis through logistical regression showed that the factors independently and significantly associated with an extended hospital stay were presurgical fever, appendix position behind the ileocecal junction, and intraoperative gangrened or perforated appearance of the appendix. CONCLUSION: Fever, appearance, and position of the appendix are factors related to an extended hospital stay. 相似文献
7.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells. 相似文献
8.
9.
10.
表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献