全文获取类型
收费全文 | 26424篇 |
免费 | 1850篇 |
国内免费 | 169篇 |
专业分类
耳鼻咽喉 | 207篇 |
儿科学 | 608篇 |
妇产科学 | 505篇 |
基础医学 | 3872篇 |
口腔科学 | 259篇 |
临床医学 | 2325篇 |
内科学 | 6125篇 |
皮肤病学 | 334篇 |
神经病学 | 2764篇 |
特种医学 | 900篇 |
外国民族医学 | 1篇 |
外科学 | 4838篇 |
综合类 | 160篇 |
一般理论 | 10篇 |
预防医学 | 1589篇 |
眼科学 | 292篇 |
药学 | 1568篇 |
中国医学 | 77篇 |
肿瘤学 | 2009篇 |
出版年
2023年 | 119篇 |
2022年 | 184篇 |
2021年 | 500篇 |
2020年 | 369篇 |
2019年 | 612篇 |
2018年 | 675篇 |
2017年 | 500篇 |
2016年 | 550篇 |
2015年 | 645篇 |
2014年 | 909篇 |
2013年 | 1235篇 |
2012年 | 1851篇 |
2011年 | 1991篇 |
2010年 | 1224篇 |
2009年 | 1152篇 |
2008年 | 1759篇 |
2007年 | 1816篇 |
2006年 | 1690篇 |
2005年 | 1765篇 |
2004年 | 1566篇 |
2003年 | 1582篇 |
2002年 | 1603篇 |
2001年 | 255篇 |
2000年 | 210篇 |
1999年 | 284篇 |
1998年 | 346篇 |
1997年 | 332篇 |
1996年 | 230篇 |
1995年 | 226篇 |
1994年 | 180篇 |
1993年 | 173篇 |
1992年 | 148篇 |
1991年 | 137篇 |
1990年 | 126篇 |
1989年 | 97篇 |
1988年 | 100篇 |
1987年 | 82篇 |
1986年 | 109篇 |
1985年 | 97篇 |
1984年 | 98篇 |
1983年 | 95篇 |
1982年 | 107篇 |
1981年 | 95篇 |
1980年 | 94篇 |
1979年 | 63篇 |
1978年 | 51篇 |
1977年 | 47篇 |
1976年 | 41篇 |
1974年 | 44篇 |
1973年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
991.
Identification of a gene causing human cytochrome c oxidase deficiency by integrative genomics 总被引:2,自引:0,他引:2
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
992.
Feng Y Yu S Lasell TK Jadhav AP Macia E Chardin P Melancon P Roth M Mitchison T Kirchhausen T 《Proceedings of the National Academy of Sciences of the United States of America》2003,100(11):6469-6474
A phenotypic screen was used to search for drug-like molecules that can interfere with specific steps in membrane traffic. 2-(4-Fluorobenzoylamino)-benzoic acid methyl ester (Exo1), identified in this screen, induces a rapid collapse of the Golgi to the endoplasmic reticulum, thus acutely inhibiting the traffic emanating from the endoplasmic reticulum. Like Brefeldin A (BFA), Exo1 induces the rapid release of ADP-ribosylation factor (ARF) 1 from Golgi membranes but has less effect on the organization of the trans-Golgi network. Our data indicate that Exo1 acts by a different mechanism from BFA. Unlike BFA, Exo1 does not induce the ADP-ribosylation of CtBP/Bars50 and does not interfere with the activity of guanine nucleotide exchange factors specific for Golgi-based ARFs. Thus, Exo1 allows the fatty acid exchange activity of Bars50 to be distinguished from ARF1 activity in the control of Golgi tubulation. 相似文献
993.
A New Subtype of Large B-Cell Lymphoma Expressing the ALK Kinase and Lacking the 2; 5Translocation 总被引:16,自引:5,他引:16
994.
Prunet-Marcassus B Desbazeille M Bros A Louche K Delagrange P Renard P Casteilla L Pénicaud L 《Endocrinology》2003,144(12):5347-5352
Melatonin is involved in the regulation of seasonal obesity in various species, including some rodents. This involvement has been demonstrated in nonphotoperiodic rodents like rats, but only in models of enhanced body weight such as genetically obese or middle-aged rats. The aim of this investigation was to determine the effects of melatonin on body weight and metabolic parameters in a model closer to that observed in Western populations, i.e. Sprague Dawley rats fed a high-fat diet. They were treated for 3 wk with melatonin (30 mg/kg) 4 h after lights-on [Zeitgeber time (ZT) 4] or 1 h before lights-out (ZT11). Given at ZT11, melatonin decreased body weight gain and feed efficiency by half. Melatonin had no effect on plasma insulin level, but it decreased plasma glucose (13%), leptin (28%), and triglyceride (28%) levels. Furthermore, in pinealectomized high-fat diet rats, body weight gain and feed efficiency were increased 4 wk after surgery. Adipose tissue weight, insulinemia, and glycemia had a tendency to increase. Treatment with melatonin prevented in part these changes. These data demonstrate that melatonin may act as a regulator of body weight in a model of obesity and may prevent some of the side effects on glucose homeostasis such as decreased insulin sensitivity. 相似文献
995.
Demuth K Drunat S Girerd X Moatti N Paul JL Safar M Boutouyrie P 《Atherosclerosis》2002,165(1):167-174
Several authors have reported that moderate hyperhomocysteinemia is related to asymptomatic carotid arterial wall remodeling, but few data are available on other thiol compounds with potential vascular toxicity. We, therefore, investigated the relationships between major plasma thiol compounds (homocysteine, cysteine and glutathione) and the structural phenotype of the common carotid artery in a cohort of 123 subjects with no evidence of cardiovascular disease. Fasting levels of thiol compounds were measured by high-performance liquid chromatography, and arterial geometry was evaluated using high-resolution echotracking devices. In univariate regression analysis, plasma homocysteine and plasma cysteine concentrations were positively associated with carotid artery internal diameter (P=0.0001 and 0.002, respectively) and intima media thickness (P=0.003 and 0.004), but the plasma glutathione concentration was not. In multivariate analysis, plasma homocysteine was independently and positively associated with carotid artery internal diameter (P<0.005) and intima media thickness (P<0.05), but plasma cysteine was not. These data suggest that homocysteine is the only plasma thiol compound that may be considered as a risk factor for preclinical cardiovascular disease. 相似文献
996.
Gene transfer by guanidinium-cholesterol cationic lipids into airway epithelial cells in vitro and in vivo
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Noufissa Oudrhiri Jean-Pierre Vigneron Michel Peuchmaur Tony Leclerc Jean-Marie Lehn Pierre Lehn 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(5):1651-1656
Synthetic vectors represent an attractive alternative approach to viral vectors for gene transfer, in particular into airway epithelial cells for lung-directed gene therapy for cystic fibrosis. Having recently found that guanidinium-cholesterol cationic lipids are efficient reagents for gene transfer into mammalian cell lines in vitro, we have investigated their use for gene delivery into primary airway epithelial cells in vitro and in vivo. The results obtained indicate that the lipid bis(guanidinium)-tren-cholesterol (BGTC) can be used to transfer a reporter gene into primary human airway epithelial cells in culture. Furthermore, liposomes composed of BGTC and dioleoyl phosphatidylethanolamine (DOPE) are efficient for gene delivery to the mouse airway epithelium in vivo. Transfected cells were detected both in the surface epithelium and in submucosal glands. In addition, the transfection efficiency of BGTC/DOPE liposomes in vivo was quantitatively assessed by using the luciferase reporter gene system. 相似文献
997.
Azar ST Salti I Zantout MS Shahine CH Zalloua PA 《The American journal of the medical sciences》2002,323(4):206-209
Leptin is the protein product of the obese (ob) gene, a lipostatic hormone that contributes to body weight regulation through suppressing appetite and/or stimulating energy expenditure in humans and/or rodents. In humans, serum leptin concentrations are increased in relation to increased body fat content. Studies have shown a higher leptin level in women compared with men. However, the gender influence on serum leptin concentrations has never been evaluated in patients with type 1 diabetes. In this study, serum leptin levels and percentage body fat mass were measured in men and women with type 1 diabetes. Fasting serum leptin levels were higher in women (16.7 + 11.6 ng/mL) than in men (3.0 +/- 1.5 ng/mL; P < 0.05) and were independent of exogenous insulin intake and of glucose control. Percentage body fat and fat mass were significant determinants of leptin concentration, whereas age and duration of diabetes were not related to leptin concentration. Subgroups of men (n = 12) and women (n = 11) with total body fat between 20 and 30% were compared. Leptin levels were also higher in women compared with men (13.5 +/- 8.3 ng/mL versus 3.2 +/- 1.7 ng/mL; P < 0.05, respectively). In conclusion, our findings indicate that gender is an important determinant of serum leptin concentration in type 1 diabetics, this gender difference is partly explained by body fat distribution and that type 1 diabetic women may be more resistant than type 1 diabetic men to leptin's alleged lipostatic actions. 相似文献
998.
Dr. Pierre Novello MD Pierre Duvillard MD Sophie Grandjouan MD Dominique Elias MD Philippe Rougier MD Caroline Bognel MD Michel Prade MD 《Digestive diseases and sciences》1995,40(1):100-106
Summary Two cases of colonic carcinomas with multidirectional differentiation are presented. Both tumors showed light microscopic and immunohistochemical evidence of areas of adenocarcinomatous, squamous cell carcinomatous, and neuroendocrine differentiation. Only six similar cases have been previously reported. These highly malignant tumors support the recent concept of a multipotential stem cell within the mucosa of the gastrointestinal tract capable of differentiation in several directions. 相似文献
999.
Evidence for a lipochaperonin: Association of active proteinfolding GroESL oligomers with lipids can stabilize membranes under heat shock conditions
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Zsolt Trk Ibolya Horvth Pierre Goloubinoff Eszter Kovcs Attila Glatz Gbor Balogh Lszl Vígh 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(6):2192-2197
During heat shock, structural changes in proteins and membranes may lead to cell death. While GroE and other chaperone proteins are involved in the prevention of stress-induced protein aggregation and in the recovery of protein structures, a mechanism for short-term membrane stabilization during stress remains to be established. We found that GroEL chaperonin can associate with model lipid membranes. Binding was apparently governed by the composition and the physical state of the host bilayer. Limited proteolysis of GroEL oligomers by proteinase K, which removes selectively the conserved glycine- and methionine-rich C terminus, leaving the chaperonin oligomer intact, prevented chaperonin association with lipid membranes. GroEL increased the lipid order in the liquid crystalline state, yet remained functional as a protein-folding chaperonin. This suggests that, during stress, chaperonins can assume the functions of assisting the folding of both soluble and membrane-associated proteins while concomitantly stabilizing lipid membranes. 相似文献
1000.
Edith Hummler Pierre Barker Colleen Talbot Qing Wang Chantal Verdumo Barbara Grubb John Gatzy Michel Burnier Jean-Daniel Horisberger Friedrich Beermann Richard Boucher Bernard C. Rossier 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(21):11710-11715
Aldosterone-dependent epithelial sodium transport in the distal nephron is mediated by the absorption of sodium through the highly selective, amiloride-sensitive epithelial sodium channel (ENaC) made of three homologous subunits (α, β, and γ). In human, autosomal recessive mutations of α, β, or γENaC subunits cause pseudohypoaldosteronism type 1 (PHA-1), a renal salt-wasting syndrome characterized by severe hypovolemia, high plasma aldosterone, hyponatremia, life-threatening hyperkaliemia, and metabolic acidosis. In the mouse, inactivation of αENaC results in failure to clear fetal lung liquid at birth and in early neonatal death, preventing the observation of a PHA-1 renal phenotype. Transgenic expression of αENaC driven by a cytomegalovirus promoter in αENaC(−/−) knockout mice [αENaC(−/−)Tg] rescued the perinatal lethal pulmonary phenotype and partially restored Na+ transport in renal, colonic, and pulmonary epithelia. At days 5–9, however, αENaC(−/−)Tg mice showed clinical features of severe PHA-1 with metabolic acidosis, urinary salt-wasting, growth retardation, and 50% mortality. Adult αENaC(−/−)Tg survivors exhibited a compensated PHA-1 with normal acid/base and electrolyte values but 6-fold elevation of plasma aldosterone compared with wild-type littermate controls. We conclude that partial restoration of ENaC-mediated Na+ absorption in this transgenic mouse results in a mouse model for PHA-1. 相似文献