全文获取类型
收费全文 | 2596篇 |
免费 | 154篇 |
国内免费 | 19篇 |
专业分类
耳鼻咽喉 | 155篇 |
儿科学 | 48篇 |
妇产科学 | 21篇 |
基础医学 | 319篇 |
口腔科学 | 38篇 |
临床医学 | 374篇 |
内科学 | 403篇 |
皮肤病学 | 29篇 |
神经病学 | 221篇 |
特种医学 | 154篇 |
外科学 | 302篇 |
综合类 | 42篇 |
一般理论 | 3篇 |
预防医学 | 384篇 |
眼科学 | 16篇 |
药学 | 97篇 |
1篇 | |
肿瘤学 | 162篇 |
出版年
2022年 | 17篇 |
2021年 | 25篇 |
2019年 | 23篇 |
2018年 | 23篇 |
2016年 | 18篇 |
2015年 | 22篇 |
2014年 | 37篇 |
2013年 | 51篇 |
2012年 | 116篇 |
2011年 | 124篇 |
2010年 | 56篇 |
2009年 | 53篇 |
2008年 | 96篇 |
2007年 | 113篇 |
2006年 | 81篇 |
2005年 | 87篇 |
2004年 | 82篇 |
2003年 | 91篇 |
2002年 | 91篇 |
2001年 | 71篇 |
2000年 | 84篇 |
1999年 | 63篇 |
1998年 | 49篇 |
1997年 | 96篇 |
1996年 | 56篇 |
1995年 | 32篇 |
1994年 | 53篇 |
1993年 | 33篇 |
1992年 | 74篇 |
1991年 | 67篇 |
1990年 | 76篇 |
1989年 | 86篇 |
1988年 | 61篇 |
1987年 | 54篇 |
1986年 | 68篇 |
1985年 | 65篇 |
1984年 | 31篇 |
1983年 | 30篇 |
1982年 | 21篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 26篇 |
1978年 | 24篇 |
1977年 | 24篇 |
1976年 | 20篇 |
1975年 | 19篇 |
1974年 | 26篇 |
1973年 | 23篇 |
1972年 | 20篇 |
1967年 | 16篇 |
排序方式: 共有2769条查询结果,搜索用时 15 毫秒
11.
Tunica vaginalis urethroplasty. 总被引:4,自引:0,他引:4
Tunica vaginalis on a vascular pedicle was tubularized and used as a urethra to repair hypospadias in three difficult cases. This is the first report of tunica vaginalis utilized for a urethral reconstruction in humans. This new surgical technique is described. 相似文献
12.
This article illustrates the buried running dermal subcutaneous suture technique, a more rapid method for closing large fusiform open skin wounds than vertically oriented buried dermal subcutaneous sutures that are individually tied and cut. This technique effectively closes dead space, provides excellent strength, and relieves wound tension uniformly. 相似文献
13.
14.
B M Greenwood A M Greenwood A K Bradley F C Shenton A W Smith R W Snow K Williams T A Eggelte H Huikeshoven M de Wit 《Bulletin of the World Health Organization》1986,64(6):909-916
Enzyme-linked immunosorbent asays (ELISAs) are described for determining levels of dapsone and pyrimethamine in urine. Both assays have a sensitivity of about 20 μg/l and are reproducible, but each produces some false positives. The problem of false positive reactions was partially obviated by requiring positive results in both assays. In a pilot study involving 50 children aged 3 months to 4 years who were given a single dose of Maloprim (pyrimethamine + dapsone), 75% were positive for dapsone 7 days after administration of the drug, while 25% were still positive 15 days after its administration. The corresponding proportions for pyrimethamine were 73% and 30%, respectively. Comparison of the results obtained in a larger chemoprophylaxis trial with those from the pilot study indicated that the assays described could be used to investigate whether antimalarials had been taken. 相似文献
15.
Methods for estimating numbers of motor units in biceps-brachialis muscles and losses of motor units with aging 总被引:4,自引:0,他引:4
This paper presents a new method, here applied to the biceps-brachialis muscles, for estimating motor unit numbers in healthy subjects. This method combines isometric contraction, intramuscular needle electrode recordings, and spike-triggered averaging techniques to measure the sizes of motor unit potentials as recorded in the innervation zone with surface electrodes. The number of motor units is then estimated by division of the maximum biceps-brachialis "M" potential recorded with the same surface electrodes and evoked by supramaximal stimulation of the musculocutaneous nerve, by the mean of at least 10 surface-recorded motor unit potentials. The requisite intramuscular recordings provide additional information as to innervation density, incidence of linked potentials, and impulse blocking, phenomena that are particularly common in neurogenic and myogenic disorders. There was clear evidence of losses of motor units in older subjects: subjects over 60 years of age having approximately half the numbers of motor units of subjects under 60 years of age. 相似文献
16.
S L Morrison-Stewart P C Williamson W C Corning S P Kutcher W G Snow H Merskey 《Psychological medicine》1992,22(2):353-359
Schizophrenic subjects performed significantly worse on neuropsychological tests of frontal lobe function but not on tests of non-frontal lobe function when compared to a matched group of normal subjects. Correlations expected between frontal lobe neuropsychological test performance and negative symptoms were not found. 相似文献
17.
18.
1. The chronotropic and inotropic effects of stimulating the vagus on the hearts of the dog, duck and toad were studied.2. The maximum rate of rise of pressure in the left ventricle (dP/dt max) measured at a constant heart rate and mean aortic pressure was used as an index of the inotropic changes.3. The sensitivity of dP/dt max as an index of inotropic changes brought about by stimulating the vagus was established in the toad where a 49% reduction in heart rate was associated with a 30% reduction in dP/dt max.4. In the dog stimulation of the vagus resulted in a reduction in heart rate of 38% and only a small reduction in dP/dt max of 6%.5. Results similar to those found in the dog were obtained in the duck where the reduction in heart rate of 44% was associated with reduction in dP/dt max of only 3%.6. It is concluded that the vagus has only a small and negligible negative inotropic effect on the ventricles of the dog and duck. 相似文献
19.
1. The morphology of physiologically identified spinocervical tract (SCT) neurones was studied using the intracellular injection of Procion dyes in anesthetized and decerebrate cats. 2. Extracellular recordings were made from SCT neurones at depths between 1000 and 2850 mum from the cord surface but neurones were only stained at depths between 1100 and 2400 mum. 3. The dendritic trees of stained SCT neurones were reconstructed in the transverse plane of the spinal cord. All SCT neurones had well developed dorsal dendrites but despite this it is not possible to consider the twenty-two SCT cells in out sample as consituting a morphologically homogenous population. 4. There was no correlation between the form of the dendritic trees and the depth of SCT neurones in the dorsal horn as determined both from measurements from the dorsal grey-white border and the position of cells with respect to the border between Rexed's laminae II and III. 5. Six types of SCT neurones were identified on the basis of the form of their dendritic trees as viewed in the transverse plane: (1) radially symmetrical, (2) semicircular, (3) large elliptical, (4) bilobed, (5) triangular, (6) small elliptical. Each of these types was found only in a certain region across the dorsal horn although any one region could contain more than one type. 6. Spinocervical tract neurones with small elliptical dendritic trees always had receptive fields encompassing part of the hip or thigh and were unique in being located in the lateral portions of the horn. 7. There was no correlation between the morphology of SCT neurones and their excitatory cutaneous inputs, receptive field size, axonal conduction velocity or depth in the dorsal horn. 相似文献
20.
Mutations in the Ca(2+)-sensing receptor gene cause autosomal dominant and sporadic hypoparathyroidism 总被引:3,自引:0,他引:3
Baron J; Winer KK; Yanovski JA; Cunningham AW; Laue L; Zimmerman D; Cutler GB Jr 《Human molecular genetics》1996,5(5):601-606
Parathyroid hormone secretion is negatively regulated by a 7- transmembrane
domain, G-protein coupled Ca(2+)-sensing receptor. We hypothesized that
activating mutations in this receptor might cause autosomal dominant
hypoparathyroidism (ADHP). Consistent with this hypothesis, we identified,
in two families with ADHP, heterozygous missense mutations in the
Ca(2+)-sensing receptor gene that cosegregated with the disorder. None of
50 normal controls had either mutation. We also identified a de novo,
missense Ca(2+)-sensing receptor mutation in a child with severe sporadic
hypoparathyroidism. The amino acid substitution in one ADHP family affected
the N-terminal, extracellular domain of the receptor. The other mutations
involved the transmembrane region. Unlike patients with acquired
hypoparathyroidism, patients with these mutations had hypercalciuria even
at low serum calcium concentrations. Their greater hypercalciuria
presumably reflected activation of Ca(2+)-sensing receptors in kidney
cells, where the receptor negatively regulates calcium reabsorption. This
augmented hypercalciuria increases the risk of renal complications and thus
has implications for the choice of therapy.
相似文献