全文获取类型
收费全文 | 16664篇 |
免费 | 999篇 |
国内免费 | 78篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 455篇 |
妇产科学 | 418篇 |
基础医学 | 2473篇 |
口腔科学 | 554篇 |
临床医学 | 1321篇 |
内科学 | 4032篇 |
皮肤病学 | 345篇 |
神经病学 | 1550篇 |
特种医学 | 612篇 |
外国民族医学 | 2篇 |
外科学 | 1511篇 |
综合类 | 69篇 |
一般理论 | 6篇 |
预防医学 | 1553篇 |
眼科学 | 366篇 |
药学 | 1224篇 |
中国医学 | 93篇 |
肿瘤学 | 1061篇 |
出版年
2023年 | 110篇 |
2022年 | 287篇 |
2021年 | 467篇 |
2020年 | 274篇 |
2019年 | 416篇 |
2018年 | 567篇 |
2017年 | 321篇 |
2016年 | 438篇 |
2015年 | 477篇 |
2014年 | 655篇 |
2013年 | 800篇 |
2012年 | 1253篇 |
2011年 | 1306篇 |
2010年 | 676篇 |
2009年 | 636篇 |
2008年 | 1019篇 |
2007年 | 1071篇 |
2006年 | 967篇 |
2005年 | 861篇 |
2004年 | 727篇 |
2003年 | 758篇 |
2002年 | 677篇 |
2001年 | 253篇 |
2000年 | 217篇 |
1999年 | 206篇 |
1998年 | 181篇 |
1997年 | 174篇 |
1996年 | 148篇 |
1995年 | 115篇 |
1994年 | 117篇 |
1993年 | 129篇 |
1992年 | 127篇 |
1991年 | 100篇 |
1990年 | 93篇 |
1989年 | 128篇 |
1988年 | 112篇 |
1987年 | 93篇 |
1986年 | 101篇 |
1985年 | 84篇 |
1984年 | 66篇 |
1983年 | 59篇 |
1982年 | 46篇 |
1981年 | 53篇 |
1980年 | 50篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 25篇 |
1976年 | 24篇 |
1975年 | 34篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
O. Díaz Rizo S. Olivares Reumont J. Viguri Fuente O. Díaz Arado N. López Pino K. D’Alessandro Rodríguez D. de la Rosa Medero A. Gelen Rudnikas G. Arencibia Carballo 《Bulletin of environmental contamination and toxicology》2010,84(1):136-140
Levels of iron, copper, zinc and lead were determined in sediments and soft tissue of the oyster Crassostrea rhizophorae collected from Guacanayabo Gulf, Cuba. Metal-to-Iron ratio in sediments shows an average enrichment for Cu (5,1), Pb (11,7)
and Zn (1,3) in the last 20 years. Metal concentrations found in soft tissue of C. rhizophorae are site dependent. The average biota-sediment accumulation factors (BSAFs) obtained for Fe, Cu and Pb are less than unity
in all cases, indicating that only a little fraction of Cu and Pb in the sediments is bioavailable, independently of their
enrichments. Zinc has an average BSAF value of 2.4 and may represent a serious impact in the area. The concentrations of zinc
and copper in some of the oysters are above typical public health recommended limits. 相似文献
62.
63.
A randomized controlled trial of electromagnetic therapy in the primary care management of venous leg ulceration 总被引:1,自引:1,他引:0
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care. 相似文献
64.
Vittorio Petraccone Finizia Auriemma Francesco Dal Poggetto Claudio De Rosa Gaetano Guerra Paolo Corradini 《Macromolecular chemistry and physics.》1993,194(5):1335-1345
In this contribution, the X-ray diffraction (XRD) pattern of a highly oriented sample of syndiotactic polystyrene in the mesomorphic form, collected by an automatic diffractometer, is presented, thus providing quantitative and more complete information relative to the diffracted intensity. The structural changes induced by annealing procedures in mesomorphic samples are shown through the analysis of the XRD patterns: both unoriented and oriented mesomorphic samples are transformed gradually into α-form crystals. On the basis of these evidences and of preliminary comparisons between the calculated Fourier transform of simplified models and the experimental diffraction intensity, it is suggested that the local organization in triplets of trans-planar chains, typical of the different modifications of the α-form, would be largely present also in the disordered chain agglomerates of the mesomorphic form. 相似文献
65.
66.
67.
68.
69.
70.
A 72-year-old man presented with an apparent frontal syndrome. He also had bilateral trigeminal neuralgia, a pyramidal syndrome of all 4 limbs, balance disturbances, a horizontal nystagmus when looking to the left and a right velopalatine paralysis. CT scan with contrast showed a hyperdense rounded lesion in the left cerebello-pontine angle. Cerebral angiography showed this to be a large aneurysm of the end of the vertebral arteries. The patient died suddenly. Autopsy confirmed the site and presence of the aneurysm. Balance disturbances, the pyramidal syndrome and velopalatine paralysis could all be explained by brain stem compression and the bilateral nature of the trigeminal neuralgia by compression of the trigemino-thalamic tract. The apparent frontal syndrome, the authors suggest could have resulted from subacute raised intracranial pressure. 相似文献