全文获取类型
收费全文 | 8479篇 |
免费 | 707篇 |
国内免费 | 9篇 |
专业分类
耳鼻咽喉 | 121篇 |
儿科学 | 315篇 |
妇产科学 | 267篇 |
基础医学 | 1226篇 |
口腔科学 | 254篇 |
临床医学 | 774篇 |
内科学 | 1474篇 |
皮肤病学 | 114篇 |
神经病学 | 536篇 |
特种医学 | 540篇 |
外科学 | 1033篇 |
综合类 | 190篇 |
一般理论 | 1篇 |
预防医学 | 1382篇 |
眼科学 | 102篇 |
药学 | 532篇 |
1篇 | |
中国医学 | 8篇 |
肿瘤学 | 325篇 |
出版年
2019年 | 82篇 |
2018年 | 123篇 |
2017年 | 84篇 |
2016年 | 86篇 |
2015年 | 102篇 |
2014年 | 182篇 |
2013年 | 211篇 |
2012年 | 273篇 |
2011年 | 302篇 |
2010年 | 183篇 |
2009年 | 205篇 |
2008年 | 274篇 |
2007年 | 318篇 |
2006年 | 275篇 |
2005年 | 264篇 |
2004年 | 246篇 |
2003年 | 211篇 |
2002年 | 228篇 |
2001年 | 261篇 |
2000年 | 268篇 |
1999年 | 196篇 |
1998年 | 190篇 |
1997年 | 201篇 |
1996年 | 212篇 |
1995年 | 237篇 |
1994年 | 117篇 |
1993年 | 141篇 |
1992年 | 209篇 |
1991年 | 222篇 |
1990年 | 202篇 |
1989年 | 175篇 |
1988年 | 177篇 |
1987年 | 186篇 |
1986年 | 180篇 |
1985年 | 200篇 |
1984年 | 167篇 |
1983年 | 132篇 |
1982年 | 122篇 |
1981年 | 110篇 |
1980年 | 122篇 |
1979年 | 136篇 |
1978年 | 109篇 |
1977年 | 108篇 |
1976年 | 84篇 |
1974年 | 86篇 |
1973年 | 87篇 |
1972年 | 83篇 |
1971年 | 90篇 |
1970年 | 98篇 |
1969年 | 80篇 |
排序方式: 共有9195条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
Recessively inherited L-DOPA-responsive parkinsonism in infancy caused by a point mutation (L205P) in the tyrosine hydroxylase gene 总被引:4,自引:0,他引:4
75.
Ragweed pollen contains 11 esterase, 5 acid phosphatase, 2 alkaline phosphatose, 2 hexokinase, 2 glucose-6-phosphate dehydrogenase isozymes and one leucine amino peptidase band which can be separated by starch gel electrophoresis. The isozymes were distinguished from one another by their electrophoretic mobility, heat inactivation temperatures and antigenic differences. 相似文献
76.
77.
Characterization of melanocyte stimulating hormone receptor variant alleles in twins with red hair 总被引:7,自引:3,他引:7
The association between MSHR coding region variation and hair colour in
humans has been examined by genotyping 25 red haired and 62 non-red
Caucasians, all of whom were 12 years of age and members of a twin pair
study. Twelve amino acid substitutions were seen at 11 different sites,
nine of these being newly described MSHR variants. The previously reported
Val92Met allele shows no association with hair colour, but the three
alleles Arg151Cys, Arg160Trp and Asp294His were associated with red hair
and one Val60Leu variant was most frequent in fair/blonde and light brown
hair colours. Variant MSHR genotypes are associated with lighter skin types
and red hair (P < 0.001). However, comparison of the MSHR genotypes in
dizygotic twin pairs discordant for red hair colour indicates that the MSHR
gene cannot be solely responsible for the red hair phenotype, since five of
13 pairs tested had both haplotypes identical by state (with three of the
five having both identical by descent). Rather, it is likely that
additional modifier genes exist, making variance in the MSHR gene necessary
but not always sufficient, for red hair production.
相似文献
78.
Apoptotic cell death in mouse models of GM2 gangliosidosis and observations on human Tay-Sachs and Sandhoff diseases 总被引:5,自引:2,他引:5
Huang JQ; Trasler JM; Igdoura S; Michaud J; Hanal N; Gravel RA 《Human molecular genetics》1997,6(11):1879-1885
Tay-Sachs and Sandhoff diseases are autosomal recessive neurodegenerative
diseases resulting from the inability to catabolize GM2 ganglioside by
beta-hexosaminidase A (Hex A) due to mutations of the alpha subunit
(Tay-Sachs disease) or beta subunit (Sandhoff disease) of Hex A. Hex B
(beta beta homodimer) is also defective in Sandhoff disease. We previously
developed mouse models of both diseases and showed that Hexa-/- (Tay-Sachs)
mice remain asymptomatic to at least 1 year of age while Hexb-/- (Sandhoff)
mice succumb to a profound neurodegenerative disease by 4-6 months of age.
Here we find that neuron death in Hexb-/- mice is associated with apoptosis
occurring throughout the CNS, while Hexa-/- mice were minimally involved at
the same age. Studies of autopsy samples of brain and spinal cord from
human Tay-Sachs and Sandhoff diseases revealed apoptosis in both instances,
in keeping with the severe expression of both diseases. We suggest that
neuron death is caused by unscheduled apoptosis, implicating accumulated
GM2 ganglioside or a derivative in triggering of the apoptotic cascade.
相似文献
79.
Epithelial hyperplasia in human polycystic kidney diseases. Its role in pathogenesis and risk of neoplasia. 总被引:4,自引:2,他引:4 下载免费PDF全文
The importance of tubular epithelial hyperplasia in polycystic kidney diseases has become apparent during the last decade. Micropapillary hyperplasia occurs in autosomal dominant polycystic kidney disease, in localized cystic disease, and in acquired cystic disease. Neoplastic or severely dysplastic epithelial hyperplasia occurs in von Hippel-Lindau disease. A histopathologically distinctive epithelial hyperplasia occurs in tuberous sclerosis. In each of these conditions, epithelial hyperplasia may be related to cyst formation and may also impose an increased risk of malignancy--a risk that seems to be highest in patients under treatment with long-term hemodialysis for end-stage kidney disease. Although hyperplasia in some of these diseases may share a common pathway of development, it is more probable that the histopathologic differences reflect different pathogenetic pathways that converge on a common endpoint. 相似文献
80.
Infection of mice with Mycobacterium lepraemurium caused significant functional alterations of the mononuclear phagocyte system. Accelerated clearance of sheep red blood cells was consistently demonstrated throughout the infection and the infected mice showed progressive anaemia. Infected mice showed an enhanced ability to limit growth of phagocytosed Listeria monocytogenes in spleens during the early stages of infection, whereas moribund leprous mice lost this ability. Autoradiography showed that uninfected Kupffer cells and splenic macrophages of moribund mice could still phagocytose Listeria, suggesting that MLM infection did not affect the capacity of Listeria to localize to macrophages but interfered in some way with subsequent killing of such bacteria. The possible mechanisms underlying these observations are discussed. 相似文献