全文获取类型
收费全文 | 1989篇 |
免费 | 222篇 |
国内免费 | 34篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 74篇 |
妇产科学 | 103篇 |
基础医学 | 287篇 |
口腔科学 | 24篇 |
临床医学 | 180篇 |
内科学 | 466篇 |
皮肤病学 | 13篇 |
神经病学 | 131篇 |
特种医学 | 201篇 |
外科学 | 217篇 |
综合类 | 43篇 |
一般理论 | 1篇 |
预防医学 | 81篇 |
眼科学 | 29篇 |
药学 | 149篇 |
中国医学 | 14篇 |
肿瘤学 | 227篇 |
出版年
2023年 | 7篇 |
2022年 | 15篇 |
2021年 | 26篇 |
2020年 | 22篇 |
2019年 | 28篇 |
2018年 | 38篇 |
2017年 | 35篇 |
2016年 | 30篇 |
2015年 | 57篇 |
2014年 | 69篇 |
2013年 | 75篇 |
2012年 | 127篇 |
2011年 | 125篇 |
2010年 | 90篇 |
2009年 | 88篇 |
2008年 | 99篇 |
2007年 | 99篇 |
2006年 | 85篇 |
2005年 | 92篇 |
2004年 | 97篇 |
2003年 | 80篇 |
2002年 | 72篇 |
2001年 | 63篇 |
2000年 | 64篇 |
1999年 | 69篇 |
1998年 | 34篇 |
1997年 | 39篇 |
1996年 | 44篇 |
1995年 | 35篇 |
1994年 | 26篇 |
1993年 | 24篇 |
1992年 | 31篇 |
1991年 | 29篇 |
1990年 | 38篇 |
1989年 | 36篇 |
1988年 | 33篇 |
1987年 | 33篇 |
1986年 | 21篇 |
1985年 | 22篇 |
1984年 | 21篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 17篇 |
1980年 | 10篇 |
1979年 | 13篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 8篇 |
1972年 | 5篇 |
1971年 | 4篇 |
排序方式: 共有2245条查询结果,搜索用时 0 毫秒
1.
2.
3.
Radioiodinated tracers for the evaluation of dopamine receptors in the neonatal rat brain after hypoxic-ischemic injury 总被引:1,自引:0,他引:1
Amal Zouakia Sylvie Chalon Hank F. Kung Anne-Marie Dognon Elie Saliba Jean-Claude Besnard Denis Guilloteau 《European journal of nuclear medicine and molecular imaging》1994,21(6):488-492
In order to evaluate in vivo single-photon emission tomography (SPET) method of assessing cerebral function after hypoxic-ischemic injury in human neonates, we studied D1 and D2 dopamine receptors in a rat model. Seven-day-old rats underwent permanent unilateral common carotid ligation followed by exposure to 8% O2. Two weeks later, in brains with no visible loss of hemispheric volume, striatal dopaminergic receptors were studied, with [125I]TISCH and [1251]IBZM for the D1 and D2 dopamine receptors, respectively. Using [125I]TISCH, we observed no modifications of D1 receptors, but in contrast, ex vivo and in vitro autoradiographic experiments showed a 40% decrease in the striatal binding of [125I]IBZM on both the ipsilateral and the contralateral side to the carotid ligation. These alterations were detected with IBZM, a D2 dopamine receptor ligand usable for SPET imaging. Therefore, exploration of D2 receptors by SPET in human neonates suffering from perinatal hypoxia-ischemia may be valuable for the diagnosis and follow-up of cerebral function damages.
Correspondence to: D. Guilloteau 相似文献
4.
Sensitive immunoassays are essential for establishing the efficacy of recombinant vaccines to hepatitis B virus (HBV). These experimental vaccines include the PreS2 and S domains of the HBV envelope protein. To facilitate measurement of antibody against HBV PreS2, we employed the immuno-ligand assay with silicon sensor-based detection. Labeling of immune reagents with the haptens biotin and fluorescein allows adaptation to the immunofiltration light addressable potentiometric sensor (LAPS) system. A biotinylated monoclonal anti-PreS2 antibody and anti-PreS2 in clinical serum samples competitively bind in liquid phase to a fluorescein labeled PreS2 + S antigen. Streptavidin mediates the immobilization on biotinylated nitrocellulose membranes. Fluorescein mediates binding of an anti-fluorescein urease conjugate to the immune complex. Urease serves as the signal-generating component which subsequently is measured in the LAPS reader. In comparison to a competitive RIA, the immuno-ligand assay demonstrated a four-fold improved sensitivity using a smaller sample volume. The higher sensitivity resulted in earlier detection of seroconversion during a clinical vaccine study. 相似文献
5.
6.
A Lazaris-Karatzas M R Smith R M Frederickson M L Jaramillo Y L Liu H F Kung N Sonenberg 《Genes & development》1992,6(9):1631-1642
Translation initiation factor eIF-4E binds to the eukaryotic mRNA 5' cap structure (m7 GpppN, where N is any nucleotide). eIF-4E is a limiting factor in translation and plays a key role in regulation of translation. We have shown previously that overexpression of eIF-4E in rodent fibroblasts results in tumorigenic transformation. eIF-4E also exhibits mitogenic activity when microinjected into serum-starved NIH-3T3 cells. To understand the mechanisms by which eIF-4E exerts its mitogenic property, we examined the involvement of the Ras signaling pathway in this activity. Here, we report that Ras is activated in eIF-4E-overexpressing cells, as the proportion of GTP-bound Ras is increased. Overexpression of the negative effector of cellular Ras, GTPase activating protein, causes reversion of the transformed phenotype. Furthermore, we show that neutralizing antibodies to Ras, or a dominant-negative mutant of Ras, inhibit the mitogenic activity of eIF-4E. We conclude that eIF-4E exerts its mitogenic and oncogenic activities by the activation of Ras. 相似文献
7.
Regulation of Growth and Proliferation in B Cell Subpopulations 总被引:18,自引:0,他引:18
8.
Winston Verbi Melvyn F. Greaves Claudio Schneider Kristian Koubek George Janossy Harald Stein Patrick Kung Gideon Goldstein 《European journal of immunology》1982,12(1):81-86
Monoclonal antibodies OKT11 (γ1) and OKT11A (γ2) are described and appear to have similar binding specificities. They bind, in immunofluorescence, with >95% of infant thymocytes, staining both cortical and medullary cells, 65-80% of blood lymphocytes and selectively stain the T cell-dependent paracortical areas of tonsil. A small proportion (9-12%) of bone marrow lymphocytes stain, but this population excludes the terminal transferase-positive cells. Both the γ1 and γ2 antibodies stain the surface membrane Ig-negative lymphocytes in blood and tonsil and are able to block sheep E rosette formation (to normal or leukemic T cells). In contrast, other monoclonal anti-T reagents tested (OKT1, OKT3, OKT4, OKT6, OKT8, OKT9, OKT10) did not block E rosette formation. E rosette formation and OKT11 binding are coincident on T-ALL cell lines and both are trypsin-sensitive. In a series of 145 leukemias and 26 leukemic cell lines investigated, only leukemias with a T cell phenotype including E rosette positivity were reactive with OKT11 and OKT11A. OKT11A binds to a polypeptide of approximately 50000 molecular weight on thymic lymphocytes. This structure may carry the recognition site for sheep erythrocytes. These antibodies provide additional useful markers for T cell analysis and are of potential therapeutic value. 相似文献
9.
10.
In neurodegenerative diseases, such as Alzheimer's disease or HIV encephalitis, neuronal DNA fragmentation has been observed at unexpected high frequencies, without definitive evidence for activation of an irreversible apoptotic pathway. The wobbler mouse is a suggested genetic model of neurodegenerative disease. The mutant mouse develops normally until the fourth week of age when atrophy and weakness of forelimb muscles become apparent. There is a slow progression of the disease and wobbler mice may survive for several months. Spinal cord examination reveals the presence of several motoneurons with perikaryal vacuolar degeneration. In this study, we observed, using terminal dUTP nick-end-labelling staining in mutant spinal cord sections, a massive although very transient DNA fragmentation in different cell types, including glial cells and motoneurons, before the apparition of any clinical symptoms. In older wobbler mice, this DNA fragmentation had completely disappeared and the majority of motoneurons survived. To our knowledge, this is the first example of a massive and transient DNA fragmentation in the central nervous system during the early course of a neurodegenerative disease. 相似文献