全文获取类型
收费全文 | 14867篇 |
免费 | 735篇 |
国内免费 | 127篇 |
专业分类
耳鼻咽喉 | 197篇 |
儿科学 | 298篇 |
妇产科学 | 194篇 |
基础医学 | 2280篇 |
口腔科学 | 359篇 |
临床医学 | 1333篇 |
内科学 | 2818篇 |
皮肤病学 | 542篇 |
神经病学 | 1176篇 |
特种医学 | 650篇 |
外科学 | 2090篇 |
综合类 | 55篇 |
一般理论 | 2篇 |
预防医学 | 653篇 |
眼科学 | 376篇 |
药学 | 1384篇 |
中国医学 | 190篇 |
肿瘤学 | 1132篇 |
出版年
2023年 | 105篇 |
2022年 | 327篇 |
2021年 | 519篇 |
2020年 | 282篇 |
2019年 | 367篇 |
2018年 | 407篇 |
2017年 | 347篇 |
2016年 | 497篇 |
2015年 | 657篇 |
2014年 | 769篇 |
2013年 | 846篇 |
2012年 | 1342篇 |
2011年 | 1213篇 |
2010年 | 756篇 |
2009年 | 642篇 |
2008年 | 858篇 |
2007年 | 879篇 |
2006年 | 759篇 |
2005年 | 687篇 |
2004年 | 573篇 |
2003年 | 452篇 |
2002年 | 424篇 |
2001年 | 311篇 |
2000年 | 294篇 |
1999年 | 220篇 |
1998年 | 73篇 |
1997年 | 61篇 |
1996年 | 40篇 |
1995年 | 55篇 |
1994年 | 28篇 |
1993年 | 21篇 |
1992年 | 84篇 |
1991年 | 69篇 |
1990年 | 83篇 |
1989年 | 69篇 |
1988年 | 64篇 |
1987年 | 48篇 |
1986年 | 50篇 |
1985年 | 45篇 |
1984年 | 30篇 |
1983年 | 33篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 37篇 |
1978年 | 44篇 |
1977年 | 25篇 |
1976年 | 20篇 |
1975年 | 30篇 |
1974年 | 27篇 |
1973年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The purpose of this study was to clarify the effects of interventions that were applied to prevent endotracheal suction-induced hypoxia by meta-analysis. To obtain a sample for this meta-analysis, a computerized search was performed through MEDLINE in addition to tracking down additional references cited in bibliographies of past reports. Finally thirty research reports were examined. In terms of the application time of oxygenation, insufflation and preoxygenation were the most prevalently used in the studies. Regarding the methods of oxygenation, the most prevalent technique for oxygenation was hyperoxygenation in combination with hyperinflation. Hyperoxygenation and hyperinflation were most frequently induced by FiO2 of 1 and a 150% tidal volume of three to six breaths, respectively. Suctioning was commonly sustained for <15 seconds using pressures of -80 to -120 mmHg and with size 14 French catheters. Insufflation was less effective than the other methods examined in the present study. From this study, it can be concluded that the interventions that were applied to prevent endotracheal suction-induced hypoxia, regardless of their application times or methods, reduced suction-induced hypoxia significantly. 相似文献
992.
Effect of parenteral glutamine supplementation on plasma amino acid concentrations in extremely low-birth-weight infants 总被引:4,自引:0,他引:4
Poindexter BB Ehrenkranz RA Stoll BJ Koch MA Wright LL Oh W Papile LA Bauer CR Carlo WA Donovan EF Fanaroff AA Korones SB Laptook AR Shankaran S Stevenson DK Tyson JE Lemons JA;National Institute of Child Health Human Development Neonatal Research Network 《The American journal of clinical nutrition》2003,77(3):737-743
BACKGROUND: Glutamine is one of the most abundant amino acids in both plasma and human milk and may be conditionally essential in premature infants. However, glutamine is not provided by standard intravenous amino acid solutions. OBJECTIVE: We assessed the effect of parenteral glutamine supplementation on plasma amino acid concentrations in extremely low-birth-weight infants receiving parenteral nutrition (PN). DESIGN: A total of 141 infants with birth weights of 401-1000 g were randomly assigned to receive a standard intravenous amino acid solution that did not contain glutamine or an isonitrogenous amino acid solution with 20% of the total amino acids as glutamine. Blood samples were obtained just before initiation of study PN and again after the infants had received study PN (mean intake: 2.3 +/- 1.0 g amino acids x kg(-1) x d(-1)) for approximately 10 d. RESULTS: Infants randomly assigned to receive glutamine had mean plasma glutamine concentrations that increased significantly and were approximately 30% higher than those in the control group in response to PN (425 +/- 182 and 332 +/- 148 micromol/L for the glutamine and control groups, respectively). There was no significant difference between the 2 groups in the relative change in plasma glutamate concentration between the baseline and PN samples. In both groups, there were significant decreases in plasma phenylalanine and tyrosine between the baseline and PN samples; the decrease in tyrosine was greater in the group that received glutamine. CONCLUSIONS: In extremely low-birth-weight infants, parenteral glutamine supplementation can increase plasma glutamine concentrations without apparent biochemical risk. Currently available amino acid solutions are likely to be suboptimal in their supply of phenylalanine, tyrosine, or both for these infants. 相似文献
993.
Risk analysis of aseptic meningitis after measles-mumps-rubella vaccination in Korean children by using a case-crossover design 总被引:11,自引:0,他引:11
Epidemiologic study of a vaccine's adverse events is not easy; so many countries have no reliable data. Vaccines containing the Urabe or Hoshino strain have been withdrawn from use in several countries. However, the data are not strong enough to form the basis of a recommendation not to use specific strains. The authors used a case-crossover design to estimate the relative risk of aseptic meningitis in children after receiving the measles-mumps-rubella vaccine in Korea. Study subjects were hospitalized children aged 8-36 months who had aseptic meningitis in 1998. Cases were confirmed by hospital chart reviews using previously defined criteria. Through a telephone survey, the authors obtained vaccination date and place information from parents' vaccination records. Study results showed that no significant risk was associated with the Jeryl Lynn or Rubini strain of the vaccine (relative risk = 0.6, 95% confidence interval (CI): 0.18, 1.97). For the Urabe or Hoshino strain, the relative risk was 5.5 (95% CI: 2.6, 11.8); the risk increased in the third week after vaccination (relative risk = 15.6, 95% CI: 5.9, 41.2) and was elevated until the sixth week. The case-crossover design was useful in confirming the risk of acute adverse events after receiving vaccines. 相似文献
994.
995.
996.
997.
998.
Inhibitory activity of lignan components from the flower buds of Magnoliae fargesii on the expression of cell adhesion molecules 总被引:2,自引:0,他引:2
Inhibitory activity of lignans isolated from Magnoliae fargesii Cheng on cell adhesion molecules on the surface of THP-1 human monocytic cell lines were investigated. Among 16 lignan components tested, six displayed relatively potent inhibitory activity on the expression of both intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). 相似文献
999.
Hsin ST Chen CH Juan CH Tseng KW Oh CH Tsou MY Tsai SK 《Acta anaesthesiologica Sinica》2001,39(4):179-182
We present an instance of successful use of an intubating laryngeal mask airway (LMA-Fastrach) and a Cook airway exchanger (CAE) for ventilation and intubation in a patient with severe ankylosing spondilitis (AS) receiving total hip arthroplasty. This measure may serve as an effective alternative for airway management in patients with difficult airway. A 61-year-old male was scheduled for right total hip arthroplasty because of degenerative osteoarthritis. He had been suffering from extensive ankylosing spondylitis, with the cervical spine markedly fixed in anterior flexion. Besides he could not open his mouth widely (35 mm when fully open) also because of ankylosis of jaw. Although we advised an awake fiberoptic tracheal intubation for anesthesia but he refused owing to a previous painful experience. After induction of anesthesia with glycopyrrolate, fentanyl, thiamylal sodium and succinylcholine, we inserted a # 5 Fastrach ILMA for primary airway maintenance. Then through the lumen of the ILMA we introduced the CAE as a guide for endotracheal tube (ETT) intubation. After applying the RAPI-FIT adapter to the CAE, we connected it to the capnography monitor for the confirmation of airway. We finally inserted an endotracheal tube into the trachea using the CAE as a guide. The whole procedure was uneventful and smooth. In sum, the modified Fastrach intubation method may facilitate tracheal intubation in patients with severe ankylosing spondilitis. It may be an alternative way for successful airway management in patients with difficult airway. 相似文献
1000.
Kim JS Hwang HZ Yeo SH Ko SW Song SM Kim YK Kim DJ Oh HY Choi HY Kim MK Toru S Kohsaka T Kim Y Jin DK 《Renal failure》2001,23(1):21-29
Kidney biopsy is an indispensible procedure for making a pathologic diagnosis of renal diseases by fixing and staining the biopsy specimen. However, it is not a routine procedure to culture the cells from a renal biopsy specimen directly, or to utilize the cultured cells for any kind of diagnostic or functional evaluation. In this study, primary culture of the renal tubular epithelial cells was tried from a piece of percutaneous kidney biopsy specimen. Successive passages of the cells were possible until fourth passage. With these cells, morphologic characteristics of the cultured cells and integrin expression profiles were investigated. On light and electron microscopy, these cells were characterized by the cobblestone-like growth, presence of microvilli and tight junction, and the preservation of polarity. Immunohistochemical studies demonstrated the epithelial nature of these cells and particularly their differentiation from renal tubular epithelial cells, of either proximal or distal nephronic segment. The integrin profile confirms the epithelial nature of the cell. We hope that our results facilitate the understanding of pathophysiology of renal tubular cells from the patient directly. 相似文献