全文获取类型
收费全文 | 26760篇 |
免费 | 1642篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 271篇 |
儿科学 | 802篇 |
妇产科学 | 544篇 |
基础医学 | 3676篇 |
口腔科学 | 557篇 |
临床医学 | 3279篇 |
内科学 | 4718篇 |
皮肤病学 | 419篇 |
神经病学 | 2533篇 |
特种医学 | 1057篇 |
外国民族医学 | 25篇 |
外科学 | 2961篇 |
综合类 | 223篇 |
一般理论 | 15篇 |
预防医学 | 3277篇 |
眼科学 | 306篇 |
药学 | 2200篇 |
中国医学 | 63篇 |
肿瘤学 | 1523篇 |
出版年
2022年 | 220篇 |
2021年 | 418篇 |
2020年 | 256篇 |
2019年 | 410篇 |
2018年 | 468篇 |
2017年 | 376篇 |
2016年 | 430篇 |
2015年 | 517篇 |
2014年 | 700篇 |
2013年 | 1031篇 |
2012年 | 1477篇 |
2011年 | 1511篇 |
2010年 | 823篇 |
2009年 | 802篇 |
2008年 | 1395篇 |
2007年 | 1362篇 |
2006年 | 1405篇 |
2005年 | 1370篇 |
2004年 | 1285篇 |
2003年 | 1258篇 |
2002年 | 1135篇 |
2001年 | 625篇 |
2000年 | 637篇 |
1999年 | 567篇 |
1998年 | 300篇 |
1997年 | 221篇 |
1996年 | 199篇 |
1995年 | 224篇 |
1994年 | 234篇 |
1993年 | 303篇 |
1992年 | 614篇 |
1991年 | 575篇 |
1990年 | 465篇 |
1989年 | 324篇 |
1988年 | 318篇 |
1987年 | 293篇 |
1986年 | 243篇 |
1985年 | 300篇 |
1984年 | 230篇 |
1983年 | 168篇 |
1982年 | 150篇 |
1981年 | 146篇 |
1979年 | 180篇 |
1978年 | 153篇 |
1977年 | 137篇 |
1976年 | 141篇 |
1975年 | 150篇 |
1974年 | 193篇 |
1973年 | 158篇 |
1971年 | 135篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Stephan Koter Tina U. Cohnert Korbinian B. Hindermayr Jörg Lindenmann Maximilian Brückner Wolfgang K. Oswald Georg Werkgartner Doris Wagner 《Journal of vascular surgery》2019,69(4):1227-1232
Objective
Low psoas muscle area is shown to be an indicator for worse postoperative outcome in patients undergoing vascular surgical. Additionally, it has been associated with longer durations of hospital stay in patients with cancer who undergo surgery and subsequently greater health care costs in Europe and the United States. We sought to evaluate this effect on hospital expenditure for patients undergoing vascular repair in a health care system with universal access.Methods
Skeletal muscle mass was assessed on preoperative abdominal computed tomography scans of patients undergoing open aortic aneurysm repair in a retrospective fashion. The skeletal muscle index (SMI) was used to define low muscle mass. Health care costs were obtained for all patients and the relationship between a low SMI and higher costs was explored using linear regression and cross-sectional analysis.Results
We included 156 patients (81.5% male) with a median age of 72 years undergoing elective surgery for infrarenal abdominal aortic aneurysm in this analysis. The median SMI for patients with low skeletal muscle mass was 53.21 cm2/kg and for patients without, 70.07 cm2/kg. Hospital duration of stay was 2 days longer in patients with low skeletal muscle mass as compared with patients with normal (14 days vs 11 days; P = .001), as was duration of intensive care stay (3 days vs 1 day; P = .01). The median overall hospital costs were €10,460 higher for patients with a low SMI as compared with patients with a normal physical constitution (€53,739 [interquartile range, €45,007-€62,471] vs €43,279 [interquartile range, €39,509-€47,049]; P = .001). After confounder adjustment, a low SMI was associated with a 14.68% cost increase in overall hospital costs, for a cost increase of €6521.Conclusions
Low skeletal muscle mass is independently associated with higher hospital as well as intensive care costs in patients undergoing elective aortic aneurysm repair. Strategies to reduce this risk factor are warranted for these patients. 相似文献3.
Membrane trafficking processes are presumably vital for axonal regeneration after injury, but mechanistic understanding in this regard has been sparse. A recent loss-of-function screen had been carried out for factors important for axonal regeneration by cultured cortical neurons and the results suggested that the activity of a number of Rab GTPases might act to restrict axonal regeneration. A loss of Rab27b, in particular, is shown to enhance axonal regeneration in vitro, as well as in C. elegans and mouse central nervous system injury models in vivo. Possible mechanisms underlying this new finding, which has important academic and translational implication, are discussed. 相似文献
4.
Robin L. Bissinger MSN RNC NNP Cheryl A. Carlson MS RNC NNP 《Newborn and Infant Nursing Reviews》2006,6(2):87
Surfactant, a complex substance containing specific proteins and phospholipids, is essential for gas exchange in the lungs. Research shows that surfactant not only lowers surface tension, but also plays a role in host defense. Surfactant replacement therapy is a cornerstone in the treatment of respiratory distress syndrome in premature infants. New information on endogenous surfactant composition including surfactant apoproteins has led to advances in the surfactant replacement products currently available. Because of the success of surfactant deficiency treatment in neonates, surfactant replacement therapy has been studied in both the pediatric and adult population for the treatment of other respiratory disorders. This article describes the composition, metabolism, and function of endogenous surfactant and other uses of surfactant replacement therapies in neonates. 相似文献
5.
6.
B. Ehlers E. Strauch M. Goltz D. Kubsch H. Wagner H. Maidhof J. Bendiek B. Appel H. -J. Buhk 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》1997,40(4):118-121
Zusammenfassung Ein PCR-Nachweis für gentechnisch ver?nderten Mais ?Event 176? der Fa. Ciba-Geigy wurde etabliert. Der Mais enth?lt Gene,
die Selbstschutz gegen den Maiszünsler (Delta-Endotoxin-Gen ausBacillus thuringiensis) und Toleranz gegen das Herbizid Basta (Phosphinothricin-Resistenz-Gen ausStreptomyces hygroscopicus) vermitteln. Zudem enth?lt der Mais ein Ampicillin-Resistenz-Gen. Für die Amplifikation von Bereichen aus allen drei Genen
wurden PCR-Primer entworfen. Mit Hilfe dieser Primer und mit ?Event 176?-Mais-DNA als Template konnten die entsprechenden
Genbereiche in der PCR amplifiziert werden. Die PCR-Produkte wurden sequenziert, um ihre Identit?t zu best?tigen. Mit Hilfe
der Delta-Endotoxin-PCR wurden, auch in Gegenwart von 104fachem überschu? nicht gentechnisch ver?nderter Mais-DNA, fünf haploide Genome der ?Event 176?-DNA nachgewiesen.
Identification of genetically modified maize by PCR
Summary A PCR-test for the genetically modified maize ?Event 176? of Ciba-Geigy was established. The maize contains genes conferring resistance to the European corn borer (delta-endotoxin gene fromBacillus thuringiensis) and tolerance to the herbicide Basta (phosphinothricin resistance gene fromStreptomyces hygroscopicus). The maize contains also an ampicillin resistance gene. Primers were designed and using ?Event 176?-maize-DNA as template internal regions of the three genes were amplified with PCR. The PCR products were sequenced to confirm their identity. Using the deltaendotoxin primers in PCR down to 5 haploid genomes of ?Event 176?-DNA could be detected, even in the presence of a 104fold excess of DNA from non-modified maize.相似文献
7.
8.
Cheryl Wallerstedt RNC MS Patricia Higgins RN PhD 《Journal of obstetric, gynecologic, and neonatal nursing : JOGNN / NAACOG》1996,25(5):389-400
Society often expects mothers and fathers to share equally in the perinatal grief process because the child was a common bond between them. Unfortunately, in perinatal grief, this is not always the case. The mother and the father can experience incongruent grieving and use discordant coping mechanisms. It is important to evaluate these differences to facilitate communication between the distraught parents. Improved communication can in turn facilitate the grieving process. 相似文献
9.
10.
Humoral and cellular immunity following severe head injury: review and current investigations. 总被引:9,自引:0,他引:9
Infection is a common and serious complication of severe head injury. Immunocompetence in 25 severely head injured patients was investigated by measuring: (1) delayed-type hypersensitivity (DTH) skin test responses to common antigens; (2) phytohaemagglutinin (PHA) stimulated peripheral blood lymphocyte (PBL): blastogenesis, phenotype expression, and lymphokine production; (3) lymphokine-activated killer (LAK) cytotoxicity, antibody dependent cellular cytotoxicity (ADCC) and natural killer (NK) cytotoxicity; and (4) immunoglobulin and complement levels. The incidence of anergy to DTH skin testing was 100%. There was a decrease in PHA stimulated: PBL blastogenesis (p = 0.002), T-cell expression (p = 0.018), helper T-cell expression (p less than 0.001), interleukin-2 receptor expression (p less than 0.001), interleukin-2 production (p = 0.035) and gamma-interferon production (p less than 0.001). LAK cytotoxicity was depressed following incubation with IL-2 (p less than 0.001). There was no significant decrease in immunoglobulin levels and all acute phase reactants tested increased. The results of this study indicate that the cellular arm of immune response, including lymphocyte activation and cytokine production, is suppressed following severe head injury. The lack of enhancement in LAK cytotoxicity following incubation of PBLs with interleukin-2 suggests that factors other than decreased interleukin-2 production, such as the inherent lymphocyte dysfunction, other soluble mediators or suppressor cells, may be responsible for the reduction in cellular immunity observed following severe head injury. 相似文献