全文获取类型
收费全文 | 2064篇 |
免费 | 131篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 73篇 |
妇产科学 | 58篇 |
基础医学 | 395篇 |
口腔科学 | 50篇 |
临床医学 | 143篇 |
内科学 | 374篇 |
皮肤病学 | 50篇 |
神经病学 | 120篇 |
特种医学 | 88篇 |
外科学 | 382篇 |
综合类 | 30篇 |
预防医学 | 151篇 |
眼科学 | 27篇 |
药学 | 108篇 |
中国医学 | 5篇 |
肿瘤学 | 153篇 |
出版年
2023年 | 12篇 |
2022年 | 13篇 |
2021年 | 25篇 |
2020年 | 27篇 |
2019年 | 46篇 |
2018年 | 51篇 |
2017年 | 30篇 |
2016年 | 38篇 |
2015年 | 49篇 |
2014年 | 63篇 |
2013年 | 72篇 |
2012年 | 122篇 |
2011年 | 114篇 |
2010年 | 93篇 |
2009年 | 74篇 |
2008年 | 86篇 |
2007年 | 98篇 |
2006年 | 100篇 |
2005年 | 92篇 |
2004年 | 88篇 |
2003年 | 80篇 |
2002年 | 81篇 |
2001年 | 75篇 |
2000年 | 43篇 |
1999年 | 49篇 |
1998年 | 31篇 |
1997年 | 28篇 |
1996年 | 21篇 |
1995年 | 15篇 |
1994年 | 23篇 |
1993年 | 16篇 |
1992年 | 31篇 |
1991年 | 34篇 |
1990年 | 28篇 |
1989年 | 29篇 |
1988年 | 36篇 |
1987年 | 35篇 |
1986年 | 29篇 |
1985年 | 23篇 |
1984年 | 26篇 |
1983年 | 19篇 |
1981年 | 11篇 |
1979年 | 16篇 |
1978年 | 23篇 |
1977年 | 10篇 |
1975年 | 9篇 |
1974年 | 12篇 |
1972年 | 10篇 |
1971年 | 12篇 |
1968年 | 13篇 |
排序方式: 共有2219条查询结果,搜索用时 15 毫秒
41.
42.
Luk KC Holzmayer V Ndembi N Swanson P Brennan CA Ngansop C Mbanya D Kaptué L Gürtler L Devare SG Hackett J 《AIDS research and human retroviruses》2008,24(10):1309-1314
Recombinant forms of HIV-1 contribute significantly to the ongoing epidemic. In the present study, we characterized the near full-length genome of one candidate HIV-1 CRF25_cpx strain originating in Cameroon, 06CM-BA-040. Viral RNA was extracted from plasma, and the genome was obtained using RT-PCR amplification to generate 10 overlapping fragments. Bootscanning, recombination breakpoint analysis, and phylogenetic trees confirmed that 06CM-BA-040 had a genomic structure consistent with two available CRF25_cpx reference sequences. The CRF25_cpx mosaic composition consisted of nine segments derived from subtypes A and G as well as unclassified (U) regions. Subtype G and CRF25_cpx clusters diverged from each other with long branch lengths but were distinct from other known subtypes with high bootstrap support (94%). The epidemiological significance of CRF25_cpx strains is unknown; however, the availability of additional genomic sequences will improve our understanding of the overall genetic diversity within this recombinant form of HIV-1. 相似文献
43.
Dr. Yoram Elitsur Adhip P. N. Majumdar Wael A. Sakr Gordon D. Luk 《Digestive diseases and sciences》1991,36(3):335-340
Epidermal growth factor (EGF) is a potent growth factor for many tissues including the gastrointestinal tract. EGF is present in the gut lumen and is absorbed through the mucosa in the developing animals. In addition, EGF has been found to alter the immune system. In this study, we investigated thein vitro effect of EGF on normal colonic lamina propria lymphocyte DNA synthesis and ornithine decarboxylase activity. Human colonic lamina propria lymphocytes were isolated by collagenase-EDTA digestion. The effect of EGF on Con A-stimulated lymphocyte thymidine incorporation was tested. We observed that EGF suppressed DNA synthesis and ornithine decarboxylase (ODC) activity in lamina propria lymphocytes. EGF did not alter the time course of thymidine incorporation into LPL stimulated by the combination of phorbol 12,13-dibutyrate (PDB) and ionomycin. Our data suggest that (1) EGF suppresses DNA synthesis in human colonic lamina propria lymphocytes as well as ODC activity and (2) this inhibition may be mediated through protein kinase C or calcium flux. We postulate that EGF may have a role in modulating the human gut immune system.This work was supported in part by grant CA43280 from the National Institutes of Health. 相似文献
44.
45.
46.
Shinghung Mak Wilson W. K. Luk Wei Cui Shengquan Hu Karl W. K. Tsim Yifan Han 《Journal of molecular neuroscience : MN》2014,53(3):511-516
Alzheimer’s disease is a multi-factorial neurodegenerative disorder devastatingly affecting the aged population worldwide. Previous studies have shown that medicinal herbs used in traditional Chinese medicine might be benefit to Alzheimer’s disease patients. Berberine and palmatine, two isoquinoline alkaloids found in several medicinal herbs, were used for memory enhancement in China. In this study, the inhibitory effects of combined berberine and palmatine on acetylcholinesteras were evaluated using recombinant human acetylcholinesterase. Our results showed that the combination of berberine and palmatine inhibited acetylcholinesterase in a mixed competitive pattern. By the median-effect principle, the calculated combination index of the combination was less than 1, suggesting that berberine and plamatine inhibited acetylcholinesterase synergistically. Furthermore, the drug-reducing index of berberine and palmatine were 2.98 and 2.66, respectively. Taken together, the results showed that the combination of the two alkaloids might potentially be developed as a more effective therapeutic strategy for Alzheimer’s disease patients. 相似文献
47.
Xiang-Hui Zou Heidi Qun-Hui Xie Guang-Cai Zha Vicky Ping Chen Yan-Jie Sun Yu-Zhong Zheng Karl Wah-Keung Tsim Tina Ting-Xia Dong Roy Chi-Yan Choi Wilson Kin-Wai Luk 《Journal of molecular neuroscience : MN》2014,53(3):424-428
Cholinesterases (ChEs) have been identified in vertebrates and invertebrates. Inhibition of ChE activity in invertebrates, such as bivalve molluscs, has been used to evaluate the exposure of organophosphates, carbamate pesticides, and heavy metals in the marine system. The golden apple snail (Pomacea canaliculata) is considered as one of the worst invasive alien species harmful to rice and other crops. The ChE(s) in this animal, which has been found recently, but poorly characterized thus far, could serve as biomarker(s) for environmental surveillance as well as a potential target for the pest control. In this study, the tissue distribution, substrate preference, sensitivity to ChE inhibitors, and molecular species of ChEs in P. canaliculata were investigated. It was found that the activities of both AChE and BChE were present in all test tissues. The intestine had the most abundant ChE activities. Both enzymes had fair activities in the head, kidney, and gills. The BChE activity was more sensitive to tetra-isopropylpyrophosphoramide (iso-OMPA) than the AChE. Only one BChE molecular species, 5.8S, was found in the intestine and head, whereas two AChE species, 5.8S and 11.6S, were found there. We propose that intestine ChEs of this snail may be potential biomarkers for manipulating pollutions. 相似文献
48.
B. Bakos Á. Lukáts P. Lakatos G. Győri A. Tremmel I. Takács 《Osteoporosis international》2014,25(5):1643-1646
Fibrogenesis imperfecta is an extremely rare acquired progressive bone disorder of unknown etiology. In its course, normal bone architecture is replaced at sites by structurally unsound collagen-deficient tissue resulting in a disorganized bone structure and a skeleton that is radically susceptible to deformity and fracture. Herein, we report the case of a patient who had experienced constant bone pain and several spontaneous fractures since 1997. In 10 years’ time with the sole exception of his skull, the disease affected the entire skeleton causing a significant decrease in height and progressive disablement. Laboratory findings included elevation of serum alkaline phosphatase and C-terminal telopeptide of type 1 collagen, with normal serum calcium, phosphate, 25-hydroxy-vitamin-D, and parathyroid hormone concentrations. Monoclonal gammopathy was present with no pathological plasma cells in bone marrow. Radiological and histological results were inconclusive suggesting either osteoporosis, osteomalacia, or Paget’s disease and later on osteosclerosis. Treatment administered for the abovementioned conditions has proven to be of no effect. The findings eventually raised the possibility of fibrogenesis imperfecta ossium, which was confirmed by polarized light microscopy as well as transmission electron microscopy. The suggested therapy for the disease is melphalan that could not be initiated due to legal restrictions. Steroid monotherapy also reported to be moderately successful in one case resulted in no improvement. Paraproteinemia had been suggested not only to be a characteristic feature but also a possible etiological factor in this condition. In 2012, plasmapheresis was initiated monthly at the beginning, later on biweekly. In response, the patient’s symptoms improved dramatically supporting the abovementioned theory. 相似文献
49.
50.