全文获取类型
收费全文 | 106742篇 |
免费 | 9138篇 |
国内免费 | 4672篇 |
专业分类
耳鼻咽喉 | 1454篇 |
儿科学 | 1308篇 |
妇产科学 | 1689篇 |
基础医学 | 15460篇 |
口腔科学 | 2442篇 |
临床医学 | 10886篇 |
内科学 | 19097篇 |
皮肤病学 | 1791篇 |
神经病学 | 7011篇 |
特种医学 | 4380篇 |
外国民族医学 | 27篇 |
外科学 | 13257篇 |
综合类 | 10136篇 |
现状与发展 | 14篇 |
一般理论 | 10篇 |
预防医学 | 6103篇 |
眼科学 | 2665篇 |
药学 | 10218篇 |
38篇 | |
中国医学 | 3177篇 |
肿瘤学 | 9389篇 |
出版年
2024年 | 181篇 |
2023年 | 1062篇 |
2022年 | 2447篇 |
2021年 | 3558篇 |
2020年 | 2528篇 |
2019年 | 2617篇 |
2018年 | 3135篇 |
2017年 | 2683篇 |
2016年 | 2669篇 |
2015年 | 3600篇 |
2014年 | 4326篇 |
2013年 | 4537篇 |
2012年 | 6387篇 |
2011年 | 6575篇 |
2010年 | 4028篇 |
2009年 | 3447篇 |
2008年 | 4767篇 |
2007年 | 4806篇 |
2006年 | 4488篇 |
2005年 | 4020篇 |
2004年 | 3215篇 |
2003年 | 3028篇 |
2002年 | 2680篇 |
2001年 | 5690篇 |
2000年 | 5605篇 |
1999年 | 5009篇 |
1998年 | 1976篇 |
1997年 | 1585篇 |
1996年 | 1074篇 |
1995年 | 920篇 |
1994年 | 827篇 |
1993年 | 627篇 |
1992年 | 2271篇 |
1991年 | 1942篇 |
1990年 | 1782篇 |
1989年 | 1714篇 |
1988年 | 1503篇 |
1987年 | 1367篇 |
1986年 | 1208篇 |
1985年 | 1005篇 |
1984年 | 657篇 |
1983年 | 528篇 |
1982年 | 274篇 |
1981年 | 212篇 |
1980年 | 159篇 |
1979年 | 315篇 |
1978年 | 98篇 |
1976年 | 98篇 |
1974年 | 100篇 |
1973年 | 113篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
韩巧云 《实用医学影像杂志》2007,8(2):135-136
目的探讨欧乃影在临床应用中不良反应的发生和预防措施。方法观察2003年10月至2006年7月所作1000例增强扫描者静脉注射欧乃影0.2mL/kg(其量浓度(c)为0.5mol/L)后,不良反应发生的情况。结果1000例患者中,出现不良反应6例,其中,非过敏反应3例,轻度过敏反应3例,无中度及重度过敏反应。结论欧乃影在磁共振增强扫描中不良反应发生率低,临床应用安全。 相似文献
102.
103.
X. Sun MD 《Intensive care medicine》1992,18(4):252-253
104.
Is the P300 deficit in alcoholism associated with early visual impairments (P100, N170)? An oddball paradigm 总被引:2,自引:0,他引:2
P Maurage P Philippot P Verbanck X Noel C Kornreich C Hanak S Campanella 《Clinical neurophysiology》2007,118(3):633-644
OBJECTIVE: Studies exploring chronic alcoholism with event-related potentials (ERPs) have shown delayed latency and reduced amplitude of the P300, a long-lasting positive potential reflecting decisional processing. This P300 deficit in alcoholism is generally interpreted as a disturbance in central nervous system inhibition or in memory/attention. The present study aimed at identifying if this electrophysiological deficit is already present on earlier components, and advances a new hypothesis concerning the interpretation of the P300 alteration. METHODS: Patients suffering from alcoholism and matched healthy controls had to detect, in an oddball paradigm, emotional faces among a succession of neutral faces. Behavioral performance and ERP data (recorded from 32 electrodes) were analyzed. RESULTS: In line with previous studies, data showed that alcoholism led to a P300 deficit. Moreover, we observed for the first time that this deficit begins at earlier visual (P100) and face-processing (N170) stages, and we found high positive correlations between P100, N170 and P300 for amplitude and latency values, suggesting cumulative deficits on the cognitive continuum. CONCLUSIONS: We suggest that the P300 deficit observed in chronic alcoholism could be linked to earlier visuo-spatial deficits rather than being an impairment of the specific processes linked to the P300. SIGNIFICANCE: These results call for reconsidering the interpretation of P300 impairments at a fundamental and clinical level, and shows that earlier ERP components must be taken into account in future studies. 相似文献
105.
In this paper, we address the problem of stable tracking control of a flexible macro-micro manipulator (M(3)) system. A two-layer neural network is utilized to approximate the nonlinear robot dynamic behavior of the M(3) system, and the controllers for the macro and micro arms are developed without any need for prior knowledge of the dynamic model of the controlled M(3) system. A learning algorithm for the neural network using Lyapunov stability theory is derived. It is shown that both the tracking error and the weight-tuning error are uniformly ultimately bounded under this new control scheme. Simulation results are presented and compared to those obtained using a PD controller. 相似文献
106.
Z-Y Sun J Wei L Xie Y Shen S-Z Liu G-Z Ju J-P Shi Y-Q Yu X Zhang Q Xu G P Hemmings 《European psychiatry》2004,19(6):354-357
The present study was designed to detect three single nucleotide polymorphisms (SNPs) located on 22q11 that was thought as being of particularly importance for genetic research into schizophrenia. We recruited a total of 176 Chinese family trios of Han descent, consisting of mothers, fathers and affected offspring with schizophrenia for the genetic analysis. The transmission disequilibrium test (TDT) showed that of three SNPs, rs10314 in the 3'-untranslated region of the CLDN5 locus was associated with schizophrenia (chi(2) = 4.75, P = 0.029). The other two SNPs, rs1548359 present in the CDC45L locus centromeric of rs10314 and rs739371 in the 5'-flanking region of the CLDN5 locus, did not show such an association. The global chi-square (chi(2)) test showed that the 3-SNP haplotype system was not associated with schizophrenia although the 1-df test for individual haplotypes showed that the rs1548359(C)-rs10314(G)-rs739371(C) haplotype was excessively non-transmitted (chi(2) = 5.32, P = 0.02). Because the claudin proteins are a major component for barrier-forming tight junctions that could play a crucial role in response to changing natural, physiological and pathological conditions, the CLDN5 association with schizophrenia may be an important clue leading to look into a meeting point of genetic and environmental factors. 相似文献
107.
Siew Han Chay A Bakr M Rabie 《American journal of orthodontics and dentofacial orthopedics》2002,122(1):95-102
In this case report, orthodontic intervention was used to move the gingival margin of a maxillary canine incisally by almost 9 mm to mimic a lateral incisor. Increasing the thickness of the labial plate of bone of the canine and subsequently increasing the thickness of the attached gingiva before extrusion prevented gingival recession at a later stage. In many situations, orthodontic treatment can achieve results that could not be attained by restorations and other means of cosmetic dentistry, especially when dealing with gingival margins and gingival height. A step-by-step approach to achieving these treatment objectives is described. 相似文献
108.
109.
Several weeks after porcine retinal pigment epithelial (RPE) cell cultures attain confluence, macroscopically visible brown foci appear. The cuboidal cells that form the foci contain numerous phase dark granules that do not exhibit the autofluorescence characteristic of lipofuscin. The data described here indicate that the granules are melanosomes. Electron microscopy revealed three types of electron-dense granules in these cells: simple spheres 0.3-0.5 microns in diameter, large spheres 1-2 microns in diameter, and lysosomal aggregations of the smaller spheres. The matrix of both spheres is composed of 40-nm microvesicles that were also found free in the cytoplasm and aggregated within vacuolar structures. Reversed-phase high-performance liquid chromatography of RPE cells and their media detected melanogens, i.e. intermediates of melanin biosynthesis, including several indole derivatives. The porcine RPE cultures therefore may be a useful system for studying melanogenic regulation. 相似文献
110.
NADPH-Diaphorase-Positive Neurons in Primate Cerebral Cortex Colocalize with GABA and Calcium-Binding Proteins 总被引:3,自引:3,他引:0
Neurons in the monkey cerebral cortex containing nicotinamideadenine dinucleotide phosphate-diaphorase (NADPH-d) can he dividedinto two distinct types, both nonpyramidal. Type I neurons havea large soma (diameter 2050 µm), a dense NADPH-dhistochemical reaction. and are distributed throughout the cortex,but mainly in the subcortical white matter, and are mostly aspiny.Type II cells have a small soma (< 20 µm) with lightNADPH-d reactivity and are distributed primarily in the supragranularlayers, particularly layers II and upper III. The numericaldensity of type II cells is much greater than that of type I.Type I neurons also stain for GABA and a few intracortical typeI cells contain calbindin. All type II cells found here arecolocalized with both GABA and calbindin. Neither type I nortype II cells are stained for parvalbumin. Together with previous observations that almost all corticalNADPH-d cells in various subprimates are like type I cells,we suggest that type II cells may form a group of NADPH-d-richneurons differentiated in higher mammalian cortex from a subpopulationof calbindin-containing GABAergic interneurons, and these nitricoxide-synthesizing cells may play a role in control of intracorticalneuronal activity characteristic of higher cerebral functionsin advanced mammals. 相似文献