全文获取类型
收费全文 | 761篇 |
免费 | 30篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 35篇 |
妇产科学 | 7篇 |
基础医学 | 98篇 |
口腔科学 | 40篇 |
临床医学 | 86篇 |
内科学 | 146篇 |
皮肤病学 | 22篇 |
神经病学 | 62篇 |
特种医学 | 132篇 |
外科学 | 49篇 |
综合类 | 34篇 |
预防医学 | 19篇 |
眼科学 | 2篇 |
药学 | 46篇 |
中国医学 | 1篇 |
肿瘤学 | 29篇 |
出版年
2021年 | 4篇 |
2020年 | 4篇 |
2019年 | 8篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 15篇 |
2015年 | 20篇 |
2014年 | 20篇 |
2013年 | 23篇 |
2012年 | 22篇 |
2011年 | 22篇 |
2010年 | 34篇 |
2009年 | 22篇 |
2008年 | 17篇 |
2007年 | 31篇 |
2006年 | 19篇 |
2005年 | 20篇 |
2004年 | 19篇 |
2003年 | 21篇 |
2002年 | 12篇 |
2001年 | 15篇 |
2000年 | 23篇 |
1999年 | 26篇 |
1998年 | 32篇 |
1997年 | 29篇 |
1996年 | 27篇 |
1995年 | 20篇 |
1994年 | 20篇 |
1993年 | 17篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 29篇 |
1988年 | 21篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 17篇 |
1983年 | 14篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 13篇 |
1979年 | 4篇 |
1978年 | 13篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 10篇 |
1971年 | 3篇 |
1968年 | 3篇 |
排序方式: 共有809条查询结果,搜索用时 78 毫秒
1.
Sonoelasticity imaging of prostate cancer: in vitro results 总被引:2,自引:0,他引:2
2.
Screening for early ovarian cancer 总被引:5,自引:0,他引:5
3.
R A Blouin B A Hamelin D A Smith T S Foster W J John H A Welker 《Antimicrobial agents and chemotherapy》1992,36(3):632-638
In this open-label study, the disposition of fleroxacin in liver disease in 12 healthy male volunteers, 6 male cirrhotics without ascites (group A), and 6 male cirrhotics with ascites (group B) was evaluated. Fleroxacin (400 mg) was administered orally and intravenously to each subject in a random crossover fashion. Fleroxacin was completely absorbed and achieved similar peak concentrations in plasma in all three study groups (P greater than 0.05). The volume of distribution exceeded 1 liter/kg in healthy controls and was not affected by liver impairment (P greater than 0.05). Only group B demonstrated differences in the pharmacokinetic parameters evaluated: the systemic and renal clearances of fleroxacin and the renal clearances and clearances of the two major metabolites of fleroxacin formed, N-demethyl fleroxacin and fleroxacin N-oxide, were significantly lower and the half-lives of the parent drug and its metabolites were significantly longer in group B than in healthy controls and group A (P less than 0.05). The elimination of the two metabolites appeared to be formation rate limited in all three study groups. It was concluded from this study that a 50% reduction in the fleroxacin maintenance dose in patients with liver disease appears justified only in patients with ascites. However, no change in the fleroxacin loading dose is needed in patients with compromised liver function. 相似文献
4.
David Quarcoo Tanja C Fischer Nora Peckenschneider David A Groneberg Pia Welker 《Journal of occupational medicine and toxicology (London, England)》2009,4(1):8
Background
Neurotrophin 3 (NT-3) is a member of the neurotrophin family, a group of related proteins that are known to regulate neuro-immune interactions in allergic diseases. Their cellular sources and role in the recruitment of mast cell precursors in atopic dermatitis have not been characterized in detail so far. 相似文献5.
The vascularity of 49 renal masses (26 malignant and 23 benign lesions) was investigated with duplex Doppler ultrasound. Doppler signals obtained at the margins of renal masses were defined as "tumor signals" when the Doppler-shifted frequency of the lesion exceeded the frequency shift in the ipsilateral main renal artery. These exceeded 2.5 kHz with a 3-MHz insonating frequency. Among the 26 renal masses that subsequently proved to be malignant, tumor signals were obtained in 15 of 18 (83%) untreated renal cell carcinomas, in three of four Wilms tumors, and in two patients with metastases to the kidney, but not in the one patient with lymphoma. None of the 23 benign renal masses demonstrated tumor signals. Tumor vascularity in malignant lesions gives rise to abnormal, high-velocity, Doppler-shifted signals that can help in the differential diagnosis of renal masses. 相似文献
6.
In mammals, the indolealkylamine melatonin is synthesized mainly in the pineal gland and to a lesser degree in a number of extrapineal sites. To obtain more information on its distribution, melatonin was measured in the membranous cochlea of the guinea pig. Moreover, melatonin and other serotonin derivatives were determined in organ cultures after incubation with 14C-labelled serotonin. The results show that melatonin is detectable in the organ of Corti and the basilar membrane, and to a lesser degree also in the cochlear nerve and stria vascularis, including the spiral ligament. In vitro studies reveal the occurrence of a number of radiolabelled serotonin derivatives indicating that two of the melatonin-forming enzymes, serotonin N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT) are present in membranous cochlea. It is concluded that melatonin is synthesized in the guinea pig cochlea. Its role as modulator of hair cell function is dissolved. 相似文献
7.
Detection of reactive oxygen species (ROS) and apoptosis in human fragmented embryos 总被引:8,自引:2,他引:8
Yang HW; Hwang KJ; Kwon HC; Kim HS; Choi KW; Oh KS 《Human reproduction (Oxford, England)》1998,13(4):998-1002
In human in-vitro fertilization (IVF)-embryo transfer, the in-vitro culture
environment differs from in-vivo conditions in that the oxygen
concentration is higher, and in such conditions the mouse embryos show a
higher concentration of reactive oxygen species (ROS) in simple culture
media. ROS are believed to cause damage to cell membranes and DNA
fragmentation in somatic cells. This study was conducted to ascertain the
level of H2O2 concentration within embryos and the morphological features
of cell damage induced by H2O2. A total of 62 human oocytes and embryos (31
fragmented, 15 non-fragmented embryos, 16 unfertilized oocytes) was
obtained from the IVF-embryo transfer programme. The relative intensity of
H2O2 concentrations within embryos was measured using
2',7'-dichlorodihydrofluorescein diacetate by Quanti cell 500 fluorescence
imaging and DNA fragmentation was observed with transmission electron
microscopy and an in-situ apoptosis detection kit. The H2O2 concentrations
were significantly higher in fragmented embryos (72.21 +/- 9.62, mean +/-
SEM) compared to non-fragmented embryos (31.30 +/- 3.50, P < 0.05) and
unfertilized oocytes (30.75 +/- 2.67, P < 0.05). Apoptosis was observed
only in fragmented embryos, and was absent in non-fragmented embryos.
Electron microscopic findings confirmed apoptotic bodies and cytoplasmic
condensation in the fragmented blastomeres. We conclude that there is a
direct relationship between increased H2O2 concentration and apoptosis, and
that further studies should be undertaken to confirm these findings.
相似文献
8.
9.
Pathways to care for alcohol use disorders 总被引:1,自引:0,他引:1
10.
Pellet JB Haefliger JA Staple JK Widmann C Welker E Hirling H Bonny C Nicod P Catsicas S Waeber G Riederer BM 《The European journal of neuroscience》2000,12(2):621-632
Islet-brain 1 (IB1) was recently identified as a DNA-binding protein of the GLUT2 gene promoter. The mouse IB1 is the rat and human homologue of the Jun-interacting protein 1 (JIP-1) which has been recognized as a key player in the regulation of c-Jun amino-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathways. JIP-1 is involved in the control of apoptosis and may play a role in brain development and aging. Here, IB1 was studied in adult and developing mouse brain tissue by in situ hybridization, Northern and Western blot analysis at cellular and subcellular levels, as well as by immunocytochemistry in brain sections and cell cultures. IB1 expression was localized in the synaptic regions of the olfactory bulb, retina, cerebral and cerebellar cortex and hippocampus in the adult mouse brain. IB1 was also detected in a restricted number of axons, as in the mossy fibres from dentate gyrus in the hippocampus, and was found in soma, dendrites and axons of cerebellar Purkinje cells. After birth, IB1 expression peaks at postnatal day 15. IB1 was located in axonal and dendritic growth cones in primary telencephalon cells. By biochemical and subcellular fractionation of neuronal cells, IB1 was detected both in the cytosolic and membrane fractions. Taken together with previous data, the restricted neuronal expression of IB1 in developing and adult brain and its prominent localization in synapses suggest that the protein may be critical for cell signalling in developing and mature nerve terminals. 相似文献