全文获取类型
收费全文 | 10021篇 |
免费 | 364篇 |
国内免费 | 52篇 |
专业分类
耳鼻咽喉 | 244篇 |
儿科学 | 779篇 |
妇产科学 | 388篇 |
基础医学 | 1040篇 |
口腔科学 | 228篇 |
临床医学 | 870篇 |
内科学 | 1915篇 |
皮肤病学 | 411篇 |
神经病学 | 513篇 |
特种医学 | 248篇 |
外科学 | 1504篇 |
综合类 | 347篇 |
一般理论 | 2篇 |
预防医学 | 867篇 |
眼科学 | 215篇 |
药学 | 594篇 |
1篇 | |
中国医学 | 14篇 |
肿瘤学 | 257篇 |
出版年
2017年 | 62篇 |
2016年 | 47篇 |
2015年 | 87篇 |
2014年 | 82篇 |
2013年 | 161篇 |
2012年 | 173篇 |
2011年 | 182篇 |
2010年 | 168篇 |
2009年 | 193篇 |
2008年 | 164篇 |
2007年 | 155篇 |
2006年 | 173篇 |
2005年 | 131篇 |
2004年 | 105篇 |
2003年 | 96篇 |
2002年 | 117篇 |
2001年 | 105篇 |
2000年 | 80篇 |
1999年 | 137篇 |
1998年 | 191篇 |
1997年 | 203篇 |
1996年 | 235篇 |
1995年 | 189篇 |
1994年 | 177篇 |
1993年 | 175篇 |
1992年 | 149篇 |
1991年 | 145篇 |
1990年 | 138篇 |
1989年 | 153篇 |
1988年 | 133篇 |
1987年 | 138篇 |
1986年 | 111篇 |
1985年 | 81篇 |
1984年 | 75篇 |
1983年 | 73篇 |
1982年 | 68篇 |
1981年 | 60篇 |
1980年 | 57篇 |
1979年 | 66篇 |
1978年 | 44篇 |
1977年 | 55篇 |
1976年 | 52篇 |
1959年 | 343篇 |
1958年 | 760篇 |
1957年 | 868篇 |
1956年 | 771篇 |
1955年 | 803篇 |
1954年 | 780篇 |
1949年 | 182篇 |
1948年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
To determine if impaired energy metabolism might contribute to some aspects of Alzheimer disease (AD), including the vulnerability of the CA1 region of the hippocampal formation and the altered cytoskeleton evident in neurofibrillary tangles, we examined the effects of metabolic poisons on neuronal damage and cytoskeletal disruption in the hippocampal formation. Intrahippocampal injection of 3-nitropropionic acid (3-NP) and malonic acid resulted in neuronal death, particularly in CA1. Cytoskeletal disruption included loss of dendritic MAP2, but sparing of axonal τ. MK-801 (a noncompetitive NMDA receptor antagonist) did not atenuate the lesions produced by intrahippocampal injection of malonate. MK-801, however, was effective against intrastriatal malonate. Acute systemic 3-NP resulted in neuronal damage and cytoskeletal disruption in the CA1 region of the hippocampal formation, including an extensive loss of MAP2 immuno-reactivity, but sparing of τ. The neuronal loss in CA1 was delayed as compared to striatum. Chronic intraventricular infusion of 3-NP produced a different pattern of neuronal damage. Loss of τ-1 immuno-reactivity was observed in CA3 and CA1 s. oriens, whereas MAP2 immunostaining was preserved. These results demonstrate that chronic and acute administration of metabolic inhibitors produce distinct patterns of neuronal damage and cytoskeletal disruption. The results further suggest a differential involvement of the NMDA receptor in malonate-induced neuronal damage in striatum as compared to the hippocampus. The pattern of neuronal damage and cytoskeletal disruption observed following acute metabolic impairment resembled some aspects of neurofibrillary pathology in AD, but did not result in τ hyperphosphorylation. 相似文献
2.
Restriction fragment length polymorphism of human mitochondrial DNA in a sample population from Apulia (Southern Italy) 总被引:8,自引:1,他引:7
Restriction fragment length polymorphism (RFLP) of human mitochondrial DNA was analysed in a sample of 87 subjects from Apulia (South Italy) by the restriction enzymes Hpa I, Bam HI, Hae II, Msp I, Ava II, and Hinc II using total blood cell DNA probed by human mtDNA from placenta. Five BamHI morphs were observed, two of which are new ( Bam HI-4 and -5), as well as one new Ava II morph ( Ava II-28). The association Bam HI-4/ Ava II-28 enables us to demonstrate for the first time two polymorphic Bam HI sites present together in the same mtDNA molecule. In agreement with historical data the Apulian sample has been shown to be the most heterogeneous Italian population so far tested. 相似文献
3.
GIUSEPPE PERSEO MAURO GIGLI ROBERTO DE CASTIGLIONE 《Chemical biology & drug design》1987,29(4):478-485
The synthesis of TPH-13 (Glp-Glu-Lys-Pro-Tyr-Trp-Pro-Pro-Pro-Ile-Tyr-Pro-Met-OH), a tridecapeptide isolated from the skin of the South American frog Phyllomedusa rohdei, is described and alternative approaches are discussed. 相似文献
4.
L. TIMMER-DE MIK M.D. D.M. BROEKHUIJSEN-VAN HENTEN M.D. † J.M. OLDHOFF M.D. PH.D. D.B. DE GEER M.D. ‡ V. SIGURDSSON M.D. PH.D. S.G.M.A. PASMANS M.D. PH.D. 《Pediatric dermatology》2009,26(3):358-360
Abstract: In Sweet's syndrome, the essential features are the characteristic morphology of the lesions, their histologic appearance, the dramatic response to corticosteroids and the absence of scarring. We report an 8-month-old infant in whom Sweet's syndrome was diagnosed and who developed acquired cutis laxa in the skin lesions. 相似文献
5.
6.
7.
8.
9.
10.