全文获取类型
收费全文 | 1504篇 |
免费 | 72篇 |
国内免费 | 5篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 38篇 |
妇产科学 | 30篇 |
基础医学 | 231篇 |
口腔科学 | 69篇 |
临床医学 | 95篇 |
内科学 | 319篇 |
皮肤病学 | 19篇 |
神经病学 | 137篇 |
特种医学 | 36篇 |
外科学 | 232篇 |
综合类 | 29篇 |
一般理论 | 2篇 |
预防医学 | 95篇 |
眼科学 | 52篇 |
药学 | 64篇 |
中国医学 | 5篇 |
肿瘤学 | 113篇 |
出版年
2023年 | 11篇 |
2022年 | 21篇 |
2021年 | 37篇 |
2020年 | 16篇 |
2019年 | 31篇 |
2018年 | 36篇 |
2017年 | 26篇 |
2016年 | 40篇 |
2015年 | 43篇 |
2014年 | 64篇 |
2013年 | 73篇 |
2012年 | 95篇 |
2011年 | 122篇 |
2010年 | 62篇 |
2009年 | 42篇 |
2008年 | 51篇 |
2007年 | 88篇 |
2006年 | 74篇 |
2005年 | 72篇 |
2004年 | 82篇 |
2003年 | 68篇 |
2002年 | 96篇 |
2001年 | 26篇 |
2000年 | 26篇 |
1999年 | 32篇 |
1998年 | 16篇 |
1997年 | 15篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 16篇 |
1991年 | 17篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 7篇 |
1984年 | 10篇 |
1983年 | 4篇 |
1980年 | 5篇 |
1978年 | 8篇 |
1975年 | 3篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1972年 | 4篇 |
1971年 | 10篇 |
1970年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1581条查询结果,搜索用时 15 毫秒
91.
Diffuse uterine leiomyomatosis is a rare condition distinguished from the common uterine leiomyomata by involvement of the entire myometrium by innumerable, ill-defined, often small and confluent, histologically benign smooth-muscle nodules. Fourteen cases have been previously described in the literature. We report a case of diffuse leiomyomatosis in a 39-year-old woman. Several microscopic foci of the process were microdissected for clonality analysis. All samples showed a non-random X-chromosome inactivation pattern, and thus were consistent with a monoclonal neoplastic population of cells. However, in different foci of tumor, different X chromosomes were inactivated, supporting the independent origin of neoplastic clones and rejecting the possibility of a single clonal origin of all tumor cells. The results of the molecular analysis suggest that diffuse uterine leiomyomatosis may be an exuberant example of diffuse and uniform involvement of the entire myometrium by multiple leiomyomata. HUM PATHOL 31:1429-1432. 相似文献
92.
Riccardo Ientile Tiziana Ginoprelli Giuseppe Cannav Isa Picerno Giuseppe Piedimonte 《Journal of neuroimmunology》1997,80(1-2):87-92
Beta-endorphin (β-end) was investigated for its ability to influence sequential metabolic events that accompany the movements of T-lymphocytes into the cell cycle. When cultured lymphocytes are exposed to this endogenous opioid peptide an increase in polyamine transport across cell membrane is observed. This membrane modification is an early cell cycle event, whose enhancement leads to the intracellular polyamine accumulation. It is shown that β-end is able to enhance spermidine transport and that the exposition of cells to this peptide is perceived as an apoptotic signal. The possible relationship between induction of apoptotic death and enhancement of polyamine uptake is discussed. 相似文献
93.
Satoshi Goto Kojiro Korematsu Shinji Nagahiro Yukitaka Ushio 《Acta neuropathologica》1993,86(3):302-305
Summary An immunoperoxidase technique was used to locate synaptophysin (protein p38), a major integral membrane glycoprotein of synaptic vesicles, in the rat brain. In addition to a diffuse distribution of nerve terminal stainings for synaptophysin appearing as numerous small puncta, the large-sized cells with spindled or polygonal shapes revealed perikaryal staining for synaptophysin in the striatum. The double labeling with immunofluorescence technique disclosed that the cell bodies, immunoreactive for synaptophysin, appeared to be those of the striatal giant cholinergic neurons. In addition, in rats that underwent the transient middle cerebral artery occlusion, the striatal ischemic lesions with cell type-specific injury revealed a survival of synaptophysin-positive large cells, presumably identical with the cholinergic neurons. The present study suggests that the metabolism and/or axonal transportation of synaptophysin of the giant cholinergic cells may be different from those of other neuronal populations in the striatum. Also, synaptophysin can act as a neurochemical marker for identification of the giant cholinergic neurons in the striatum of rats.Supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan 相似文献
94.
95.
Lyra IM Gonçalves MS Braga JA Gesteira Mde F Carvalho MH Saad ST Figueiredo MS Costa FF 《Cadernos de saúde pública / Ministério da Saúde, Funda??o Oswaldo Cruz, Escola Nacional de Saúde Pública》2005,21(4):1287-1290
This study focused on clinical, hematological, and molecular aspects of sickle cell anemia pediatric patients from two different cites in Brazil. Seventy-one patients from S?o Paulo and Salvador, aged 3 to 18 years, were evaluated. Hematological analyses, betaS globin gene haplotypes, and alpha2 3.7kb-thalassemia were performed. Numbers of hospitalizations due to vaso-occlusive crises, infections, stroke, and cholelithiasis were investigated. S?o Paulo had more hospitalizations from vaso-occlusion, cholelithiasis, and stroke than Salvador. The Ben/CAR genotype predominated in both cities. Alpha2 3.7kb-thalassemia had a frequency of 28.2% in Salvador, mostly with Ben/CAR genotype (45.0%), while S?o Paulo had 22.5% with similar frequencies of the Ben/ CAR and CAR/CAR genotypes. Sickle cell anemia patients from S?o Paulo also had more episodes of stroke, which was observed among CAR/CAR, atypical, and BEN/CAR haplotypes. In Salvador stroke was only observed in the Ben/CAR genotype. Cholelithiasis had similar frequencies in the two cities. These data suggest a milder phenotype among patients in Salvador, possibly due to genetic, environmental, and socioeconomic factors. Further studies are needed to elucidate modulating factors and phenotype association. 相似文献
96.
This work investigated the adsorption of autoantibodies such as anti-SS-A/Ro, anti-SS-B/La, anti-Sm, and anti-dsDNA on protein L-agarose gel. In order to determine better conditions for IgG adsorption on this matrix, some buffer systems were tested. Adsorption data were analyzed using the Langmuir and Langmuir-Freundlich isotherm models. The experimental isotherms were best described by the Langmuir-Freundlich model, which indicated negative and positive cooperativities for binding in the presence of PBS and HEPES buffers, respectively. The K(d) values for phosphate buffered saline solution (PBS) and hydroxyethylpiperazine ethanesulfonic acid (HEPES) were 2.8 x 10(-7) M and 3.2 x 10(-7) M, respectively, which indicate a high affinity between IgG and the immobilized protein L. The amount of protein adsorbed per amount of protein loaded was high for anti-Sm (44%) and anti-dsDNA (46%), but low for anti-SS-B/La (9%). The amount of albumin adsorbed was lower than 0.06 mg/mL, which may remove the need for a plasma replacement solution in clinical apheresis. 相似文献
97.
98.
Propentofylline is a phosphodiesterase inhibitor that has been shown to attenuate the onset of morphine tolerance when administered intrathecally to rats. The present studies examined whether systemic administration could be effective in attenuating morphine tolerance in non-injured rodents using a similar dosing paradigm. Propentofylline at 10, 30, or 50 mg/kg, administered intraperitoneally once daily for 5 days, was unable to attenuate morphine tolerance established by twice daily administration of 10 mg/kg morphine. These results suggest that direct delivery of propentofylline to the central nervous system (CNS) may be required in order to attenuate morphine tolerance. 相似文献
99.
To examine the role of competitive and cooperative neural interactions within the intermediate layer of superior colliculus (SC), we elevated the basal SC neuronal activity by locally injecting a cholinergic agonist nicotine and analyzed its effects on saccade performance. After microinjection, spontaneous saccades were directed toward the movement field of neurons at the injection site (affected area). For visually guided saccades, reaction times were decreased when targets were presented close to the affected area. However, when visual targets were presented remote from the affected area, reaction times were not increased regardless of the rostrocaudal level of the injection sites. The endpoints of visually guided saccades were biased toward the affected area when targets were presented close to the affected area. After this endpoint effect diminished, the trajectories of visually guided saccades remained modestly curved toward the affected area. Compared with the effects on endpoints, the effects on reaction times were more localized to the targets close to the affected area. These results are consistent with a model that saccades are triggered by the activities of neurons within a restricted region, and the endpoints and trajectories of the saccades are determined by the widespread population activity in the SC. However, because increased reaction times were not observed for saccades toward targets remote from the affected area, inhibitory interactions in the SC may not be strong enough to shape the spatial distribution of the low-frequency preparatory activities in the SC. 相似文献
100.