全文获取类型
收费全文 | 1858篇 |
免费 | 107篇 |
国内免费 | 17篇 |
专业分类
耳鼻咽喉 | 18篇 |
儿科学 | 131篇 |
妇产科学 | 20篇 |
基础医学 | 295篇 |
口腔科学 | 30篇 |
临床医学 | 111篇 |
内科学 | 280篇 |
皮肤病学 | 41篇 |
神经病学 | 101篇 |
特种医学 | 157篇 |
外科学 | 209篇 |
综合类 | 136篇 |
预防医学 | 124篇 |
眼科学 | 26篇 |
药学 | 137篇 |
中国医学 | 41篇 |
肿瘤学 | 125篇 |
出版年
2022年 | 21篇 |
2021年 | 27篇 |
2020年 | 22篇 |
2019年 | 19篇 |
2018年 | 26篇 |
2017年 | 16篇 |
2016年 | 23篇 |
2015年 | 35篇 |
2014年 | 47篇 |
2013年 | 46篇 |
2012年 | 65篇 |
2011年 | 59篇 |
2010年 | 87篇 |
2009年 | 76篇 |
2008年 | 41篇 |
2007年 | 51篇 |
2006年 | 68篇 |
2005年 | 66篇 |
2004年 | 45篇 |
2003年 | 48篇 |
2002年 | 36篇 |
2001年 | 43篇 |
2000年 | 33篇 |
1999年 | 35篇 |
1998年 | 58篇 |
1997年 | 67篇 |
1996年 | 66篇 |
1995年 | 52篇 |
1994年 | 43篇 |
1993年 | 38篇 |
1992年 | 32篇 |
1991年 | 26篇 |
1990年 | 23篇 |
1989年 | 43篇 |
1988年 | 29篇 |
1987年 | 29篇 |
1986年 | 27篇 |
1985年 | 27篇 |
1984年 | 20篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1980年 | 13篇 |
1979年 | 16篇 |
1976年 | 14篇 |
1975年 | 19篇 |
1974年 | 17篇 |
1972年 | 15篇 |
1969年 | 14篇 |
1933年 | 24篇 |
1932年 | 29篇 |
排序方式: 共有1982条查询结果,搜索用时 15 毫秒
1.
2.
Ohne Zusammenfassung 相似文献
3.
4.
Suppurative corneal ulceration in Bangladesh 总被引:8,自引:0,他引:8
AAS Dunlop MB BS ED Wright MRCPath † SA Howlader‡ I Nazrul‡ R Husain‡ K McClellan FRACO § FA Billson FRACO § 《Clinical & experimental ophthalmology》1994,22(2):105-110
Suppurative keratitis is an important preventable cause of blindness, particularly in the developing world. This study analyses 142 cases of suppurative keratitis referred to Chittagong Eye Infirmary, Bangladesh. Some 53.5% of cases were bacterial and 35.9% were fungal. The five most common pathogens were: Pseudomonas sp. 24%, Streptococcus pneumoniae 17%, Aspergillus sp. 13%, Fusarium sp. 7% and Curvularia sp. 6%. Gram stain and culture results were consistent in 62.6% of cases. Previous antibiotic treatment was a significant factor for failure of culture isolation and less so for Gram stain failure. On Gram stain, 55.9% of pseudomonal cases were missed, but only 2% of fungal cases were missed. Over all, Gram stain had a sensitivity of 62% and positive predictive value of 84% for bacterial cases, and 98% and 94% for fungal cases, respectively. Fungal ulcers were typically filamentous, but an antecedent history of trauma was not common. The most frequent injury was due to rice grains, but the inoculum appeared to be introduced during eye washing with contaminated water. Pseudomonal ulcers occurred most frequently in the monsoon season, and Fusarium cases were seen only in the hot, dry season. 相似文献
5.
6.
7.
I Rjasanowski D Michaelis W Besch H Keilacker B Ziegler W Hildmann 《Diabetes research and clinical practice》1991,11(2):107-115
A study was made of glucose tolerance and insulin secretion in 33 persons who later developed insulin-dependent diabetes (aged 4-24 years) and observation continued further in the first years after manifestation. Patients who developed the typical labile type of diabetes were of normal weight and had either normal glucose tolerance tests before diagnosis or had impaired glucose tolerance (IGT) for a short interval of 2-16 months. Subjects with IGT over a significantly (p less than 0.01) longer period of 32.30 +/- 6.25 (normal body weight) or 94.71 +/- 20.62 (obese) months developed a milder form of diabetes with retarded insulin dependency in obese subjects. The severe and mild form of IDDM are distinct with respect to insulin requirement (0.75 +/- 0.03 or 0.28 +/- 0.04 U/kg b.w., P less than 0.01) and glucagon stimulated C-peptide (0.18 +/- 0.05 or 1.41 +/- 0.27, P less than 0.01) in the first 2.5-3.5 years after onset. The two forms were not different regarding HLA-DR antigens. Islet cell surface antibodies investigated in 15 probands at 27 occasions before diabetes onset had no prognostic value. The development of a mild form of IDDM may be expected in cases with pre-existing IGT for more than one year. The insulin secretion is of low predictive value under these conditions. The observation is of practical use and theoretical interest. 相似文献
8.
Klaus-Dietmar Merboldt Harald Bruhn Wolfgang Hanicke Thomas Michaelis Jens Frahm 《Magnetic resonance in medicine》1992,25(1):187-194
Localized proton NMR spectroscopy was used to study cerebral metabolism in the visual cortex of healthy adults during rest and photic stimulation. Basal lactate levels showed considerable interindividual differences ranging from below detectability (less than 0.3 mM) to about 1 mM without consistent alteration during photic stimulation. Local brain glucose levels were significantly reduced (approximately 50%) during the entire period of photic stimulation and recovered to resting levels (approximately 0.8 mM) within 10 min after the end of stimulation. This decrease reflects the establishment of a new equilibrium due to enhanced delivery (blood flow) and enhanced consumption. The absence of lactate accumulation supports the hypothesis of a rapid efflux of lactate from brain tissue under activated conditions. 相似文献
9.
Nonheme iron in sickle erythrocyte membranes: association with phospholipids and potential role in lipid peroxidation 总被引:5,自引:0,他引:5
Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs. 相似文献
10.
Raj P. Kapur Ian Neilson Robert M.W. Hofstra Lynda W. Holloway Ron C. Michaelis Kathleen A. Leppig 《American journal of medical genetics. Part A》2002,108(1):51-56
Congenital hydrocephalus associated with aqueductal stenosis and/or agenesis of the corpus callosum has been described in newborn males with mutations in L1CAM, a gene that encodes a neural cell adhesion molecule. These males usually have severe mental retardation and may have spastic paraplegia and adducted thumbs. In contrast, Hirschsprung disease, or absence of ganglion cells in the distal gut, has rarely been described in such individuals. We report a male infant who had severe hydrocephalus identified in the prenatal period with evidence of aqueductal stenosis and adducted thumbs at birth. He developed chronic constipation, and rectal biopsy confirmed the diagnosis of Hirschsprung disease. Molecular testing of the L1CAM gene revealed a G2254A mutation, resulting in a V752M amino acid substitution. A common polymorphism in RET, but no mutation, was identified. Our patient represents the third example of coincident hydrocephalus and Hirschsprung disease in an individual with an identified L1CAM mutation. We hypothesize that L1CAM‐mediated cell adhesion may be important for the ability of ganglion cell precursors to populate the gut, and that L1CAM may modify the effects of a Hirschsprung disease–associated gene to cause intestinal aganglionosis. © 2002 Wiley‐Liss, Inc. 相似文献