全文获取类型
收费全文 | 86158篇 |
免费 | 7699篇 |
国内免费 | 4068篇 |
专业分类
耳鼻咽喉 | 825篇 |
儿科学 | 1110篇 |
妇产科学 | 1472篇 |
基础医学 | 12263篇 |
口腔科学 | 2020篇 |
临床医学 | 8745篇 |
内科学 | 15275篇 |
皮肤病学 | 1289篇 |
神经病学 | 5289篇 |
特种医学 | 2813篇 |
外国民族医学 | 35篇 |
外科学 | 10975篇 |
综合类 | 9884篇 |
现状与发展 | 10篇 |
一般理论 | 8篇 |
预防医学 | 5314篇 |
眼科学 | 2286篇 |
药学 | 8365篇 |
32篇 | |
中国医学 | 2756篇 |
肿瘤学 | 7159篇 |
出版年
2024年 | 175篇 |
2023年 | 891篇 |
2022年 | 1973篇 |
2021年 | 2635篇 |
2020年 | 1792篇 |
2019年 | 1864篇 |
2018年 | 2330篇 |
2017年 | 1988篇 |
2016年 | 1894篇 |
2015年 | 2501篇 |
2014年 | 3196篇 |
2013年 | 3301篇 |
2012年 | 4605篇 |
2011年 | 4847篇 |
2010年 | 2954篇 |
2009年 | 2579篇 |
2008年 | 3533篇 |
2007年 | 3741篇 |
2006年 | 3479篇 |
2005年 | 3072篇 |
2004年 | 2490篇 |
2003年 | 2415篇 |
2002年 | 2209篇 |
2001年 | 5365篇 |
2000年 | 5259篇 |
1999年 | 4630篇 |
1998年 | 1796篇 |
1997年 | 1450篇 |
1996年 | 953篇 |
1995年 | 834篇 |
1994年 | 772篇 |
1993年 | 586篇 |
1992年 | 2136篇 |
1991年 | 1877篇 |
1990年 | 1752篇 |
1989年 | 1652篇 |
1988年 | 1435篇 |
1987年 | 1298篇 |
1986年 | 1171篇 |
1985年 | 984篇 |
1984年 | 649篇 |
1983年 | 501篇 |
1982年 | 272篇 |
1981年 | 201篇 |
1980年 | 151篇 |
1979年 | 299篇 |
1978年 | 87篇 |
1974年 | 94篇 |
1973年 | 108篇 |
1972年 | 84篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
N Curcó† X Pagerols† M García† X Tarroch‡ P Vives† 《Journal of the European Academy of Dermatology and Venereology》2006,20(3):331-333
A 40-year-old man presented a painful haemorrhagic plaque on his chest in the same location where a nodular lesion had been presented for many years. After 2 months, the plaque was replaced by a depressed lesion. The lesion diagnosed as an anetoderma was excised and the biopsy showed an atrophic dermatofibroma accompanied by aneurysmatic characteristics. 相似文献
53.
54.
55.
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
56.
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
57.
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
58.
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
59.
Principles for managing penetrating craniocerebral injuries caused by firearm missiles 总被引:1,自引:0,他引:1
X Zhang S Y Yi W P Liu Z W Zhang L G Wang A M Li 《Journal of clinical neuroscience》1996,3(3):229-233
Penetrating craniocerebral firearm injuries remain one of the most lethal causes of all trauma and are common both in war or peace time. Data were reviewed for 4140 severely head-injured patients (Glasgow Coma Scale (GCS) scores 3-8) treated at Xi-Jing Hospital between 1973 and 1993; 51 of these patients had acute penetrating craniocerebral injuries caused by firearm missiles. These patients consisted of 46 males (90.2%) and 5 females (9.8%) ranging in age from 3 months to 48 years (median 22.4 years). The lesion types included 2 tangential wounds, 37 tubular wounds and 12 through-and-through wounds. All cases were urgent with the patients in severe and unstable states. After emergency treatment and operation, 5 cases died (9.8%). Follow up studies at three months showed that 23 cases (45.1%) had made a good recovery. Moderate disability, severe disability and vegetative states in this series were 29.4%, 13.7% and 2.0% respectively. Long term follow up studies indicated that 32 were able to resume their occupation. The principles for managing penetrating craniocerebral firearm injuries and suggestions for operation are discussed. 相似文献
60.