全文获取类型
收费全文 | 7157篇 |
免费 | 385篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 210篇 |
妇产科学 | 73篇 |
基础医学 | 923篇 |
口腔科学 | 144篇 |
临床医学 | 584篇 |
内科学 | 2070篇 |
皮肤病学 | 347篇 |
神经病学 | 437篇 |
特种医学 | 231篇 |
外科学 | 714篇 |
综合类 | 42篇 |
预防医学 | 332篇 |
眼科学 | 121篇 |
药学 | 442篇 |
中国医学 | 18篇 |
肿瘤学 | 803篇 |
出版年
2023年 | 56篇 |
2022年 | 122篇 |
2021年 | 179篇 |
2020年 | 104篇 |
2019年 | 147篇 |
2018年 | 180篇 |
2017年 | 142篇 |
2016年 | 136篇 |
2015年 | 145篇 |
2014年 | 200篇 |
2013年 | 234篇 |
2012年 | 439篇 |
2011年 | 392篇 |
2010年 | 270篇 |
2009年 | 192篇 |
2008年 | 306篇 |
2007年 | 339篇 |
2006年 | 378篇 |
2005年 | 340篇 |
2004年 | 312篇 |
2003年 | 330篇 |
2002年 | 329篇 |
2001年 | 184篇 |
2000年 | 172篇 |
1999年 | 168篇 |
1998年 | 84篇 |
1997年 | 70篇 |
1996年 | 52篇 |
1995年 | 45篇 |
1994年 | 48篇 |
1993年 | 43篇 |
1992年 | 121篇 |
1991年 | 111篇 |
1990年 | 119篇 |
1989年 | 126篇 |
1988年 | 87篇 |
1987年 | 99篇 |
1986年 | 104篇 |
1985年 | 103篇 |
1984年 | 78篇 |
1983年 | 79篇 |
1982年 | 37篇 |
1980年 | 26篇 |
1979年 | 47篇 |
1978年 | 31篇 |
1977年 | 23篇 |
1976年 | 22篇 |
1974年 | 38篇 |
1973年 | 21篇 |
1972年 | 27篇 |
排序方式: 共有7570条查询结果,搜索用时 15 毫秒
1.
Mariko Morimoto 《Health marketing quarterly》2020,37(2):108-123
AbstractThis research explores how the level of consumers’ need for cognition (NFC) is associated with celebrity endorser credibility and examines its effects on advertising-related attitudes. A 3 (endorser types: actor/actress, athlete, TV personality/talent) × 2 (endorser’s gender) factorial experiment with 435 Japanese consumers was conducted. Concerning Japanese OTC drug advertising, lower NFC individuals perceived celebrity endorsers as more credible in comparison to higher NFC individuals. The main effects of NFC and endorser type on endorser credibility existed; however, no interaction between the two variables was found. The endorser type had an influence on attitudes toward ads and the advertised brand. 相似文献
2.
3.
Kei Kamide Yoshihiro Kokubo Hironori Hanada Junko Nagura Jin Yang Shin Takiuchi Chihiro Tanaka Mariko Banno Yoshikazu Miwa Masayoshi Yoshii Tetsutaro Matayoshi Hisayo Yasuda Takeshi Horio Akira Okayama Hitonobu Tomoike Yuhei Kawano Toshiyuki Miyata 《Hypertension research》2006,29(4):243-252
Mutations in the gene encoding 11beta-hydroxysteroid dehydrogenase type 2, HSD11B2, cause a rare monogenic juvenile hypertensive syndrome called apparent mineralocorticoid excess (AME). In AME, defective HSD11B2 enzyme activity results in overstimulation of the mineralocorticoid receptor (MR) by cortisol, causing sodium retention, hypokalemia, and salt-dependent hypertension. Here, we have studied whether genetic variations in HDS11B2 are implicated in essential hypertension in Japanese hypertensives and the general population. By sequencing the entire coding region and the promoter region of HDS11B2 in 953 Japanese hypertensives, we identified five missense mutations in 11 patients (L14F, n = 5; R74H, n = 1; R147H, n = 3; T156I, n = 1; R335H, n = 1) and one novel frameshift mutation (4884Gdel, n = 1) in a heterozygous state, in addition to 19 genetic variations. All genetic variations identified were rare, with minor allele frequencies less than 0.005. Four of 12 patients with the missense/frameshift mutations showed renal failure. Four missense mutations, L14F, R74H, R147H, and R335H, were successfully genotyped in the general population, with a sample size of 3,655 individuals (2,175 normotensives and 1,480 hypertensives). Mutations L14F, R74H, R147H, and R335H were identified in hypertensives (n = 6, 8, 3, and 0, respectively) and normotensives (n = 8, 12, 5, and 0, respectively) with a similar frequency, suggesting that these missense mutations may not strongly affect the etiology of essential hypertension. Since the allele frequency of all of the genetic variations identified in this study was rare, an association study was not conducted. Taken together, our results indicate that missense mutations in HSD11B2 do not substantially contribute to essential hypertension in Japanese. 相似文献
4.
Association between commensal bacteria and opportunistic pathogens in the dental plaque of elderly individuals 总被引:2,自引:0,他引:2
A. Tada H. Senpuku Y. Motozawa A. Yoshihara N. Hanada H. Tanzawa 《Clinical microbiology and infection》2006,12(8):776-781
Opportunistic infections in the oral cavity of the elderly may increase the incidence of systemic disease. The objective of this study was to investigate the differences in the oral bacterial flora between dependent elderly (inpatients) and independent elderly (community-dwelling residents). After multiple variables were taken into account, inpatients had significantly lower detection rates than community-dwelling residents for alpha-streptococci (p < 0.001) and Neisseria (p 0.004), and higher detection rates for Pseudomonas aeruginosa (p 0.024), methicillin-resistant Staphylococcus aureus (MRSA) (p 0.011) and Actinomyces spp. (p 0.005). Among inpatients, the requirement for a high degree of care was related negatively to detection of alpha-streptococci, but was related significantly to detection of P. aeruginosa (p 0.018) or MRSA (p 0.004). Tube-fed inpatients had a significantly lower detection rate for alpha-streptococci (p 0.041) and a higher detection rate for P. aeruginosa (p 0.004) than those who did not require tube feeding. Inpatients with a history of antibiotic use had a significantly lower detection rate for alpha-streptococci (p 0.049) and a higher detection rate for MRSA (p 0.007) than those without a history of antibiotic use. The detection rates for P. aeruginosa or MRSA in inpatients without alpha-streptococci were higher than in inpatients with alpha-streptococci after controlling for age and gender (P. aeruginosa, p 0.006; MRSA, p 0.001). Overall, detection of alpha-streptococci had an inverse correlation with the detection of P. aeruginosa and MRSA in the oral cavity and is likely to be an indicator of pathogenic bacterial infection. 相似文献
5.
M Yoshino Y Sakaguchi N Kuriya Y Ohtani F Yamashita T Hashimoto K Oyanagi K Tada K Narisawa T Kitagawa 《Neuropediatrics》1991,22(4):198-202
A nationwide survey of transient hyperammonemia in newborns was carried out in Japan. A total of 18 patients, consisting of 12 male and 6 female infants, were reported from 11 facilities. These neonates exhibited hyperammonemia with plasma ammonia levels in the range from 124 to 6256 micrograms/dl. Four newborn infants of the 18 died in the neonatal period, and an additional one died in the early infancy. Among the 13 infants who were alive at the time of this survey, 6 had neurological sequelae, including mental retardation, spastic quadriplegia and epilepsy. The multivariate analysis revealed that the Apgar score at 1 minute, peak plasma ammonia concentration, birth weight and sex were significant factors affecting the prognosis of life. 相似文献
6.
Autocrine growth and tumorigenicity of interleukin 2-dependent helper T cells transfected with IL-2 gene 总被引:15,自引:5,他引:10
下载免费PDF全文
![点击此处可从《The Journal of experimental medicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
We introduced a mouse IL-2 cDNA expression vector into an IL-2-dependent mouse helper T cell line HT-2. Transfected cells secreted substantial amounts of IL-2, to which they themselves responded by proliferating without further requirement for exogenous IL-2. The proliferation was a direct function of the cell density and was inhibitable by antibodies against IL-2 or IL-2-R, indicating the autocrine nature of the proliferation. Those producing higher amounts of IL-2 were found to be tumorigenic when inoculated into nude mice. The latency period of tumor development correlated inversely with the level of IL-2 secreted. Tumor cells proliferated in vitro in an IL-2 autocrine fashion indistinguishable from that of the inoculated cells. We thus provide evidence that the aberrant activation of the IL-2 autocrine circuit can lead T cells to malignant transformation. 相似文献
7.
8.
Moussa Ndong Machiko Kazami Tsukasa Suzuki Mariko Uehara Shin-ichi Katsumata Hirohumi Inoue Ken-Ichi Kobayashi Tadahiro Tadokoro Kazuharu Suzuki Yuji Yamamoto 《Nutrition Research》2009,29(9):640-647
Iron deficiency (ID) is one of the most commonly known forms of nutritional deficiencies. Low body iron is thought to induce neurologic defects but may also play a protective role against cancer development by cell growth arrest. Thus, ID may affect cellular pathways controlling cell growth and proliferation, the mechanism of which is still not fully understood. The serine/threonine protein kinase Akt and its downstream target, the mammalian Target of Rapamycin (mTOR), is known to play a crucial role in the regulation of cell growth and survival. Therefore, we hypothesized that Akt/mTOR pathway could be influenced by ID. Three-week-old male Wistar-strain rats were divided into 3 groups and the 2 groups had free access to a control diet (C group) or an iron-deficient diet (D group). The third group (PF group) were pair-fed the control diet to the mean intake of the D group. After 4 weeks, rats were killed and their brains were sampled. In separate experiments, COS-1 cells were cultured with or without the iron chelator deferoxamine. Western blots of brain samples and COS-1 lysates were used to analyze the expression and phosphorylation state of Akt, TSC2, mTOR, and S6 kinase proteins implicated in the Akt/mTOR pathway. Using 2 different ID models, we show for the first time that iron deficiency depresses Akt activity in rats and in COS-1 cells, leading to a decrease in mTOR activity. 相似文献
9.
10.
The kinetics and dynamics of glial fibrillary acidic protein (GFAP) assembly was explored by a fluorescence energy transfer assay method. Purified GFAP was stoichiometrically labeled at a single cysteine residue with fluorescein-maleimide. Soluble labeled GFAP in a low ionic strength buffer was assembled into 10 nm filaments by rapidly increasing the ionic strength, and the kinetics of GFAP assembly was monitored by the reduction in fluorescence due to self-quenching of fluorescein. The extent of fluorescence quench correlated with both the formation of 10 nm filament morphology and the amount of protein pelleted at 12,000g. The assembly of GFAP is critically dependent upon both protein and magnesium ion concentration, and at the critical concentration for GFAP assembly is approximately 40 micrograms/ml. Disassembly of GFAP filaments was also observed as a relief of fluorescence quenching after dilution of labeled GFAP filaments. When labeled GFAP filaments were mixed with an excess of unlabeled filaments, a rapid increase of fluorescence was observed, which is due to an exchange of subunits between labeled and unlabeled GFAP filaments. These results indicate that GFAP filaments are dynamic structures and that a small pool of kinetically active unassembled GFAP subunits are in a dynamic equilibrium with assembled GFAP filaments. The ability of GFAP to assemble, disassemble, and undergo subunit exchange has important implications for the organization and dynamics of astroglia cell cytoskeleton during development and in response to injury. 相似文献