全文获取类型
收费全文 | 11097篇 |
免费 | 635篇 |
国内免费 | 44篇 |
专业分类
耳鼻咽喉 | 73篇 |
儿科学 | 304篇 |
妇产科学 | 108篇 |
基础医学 | 1429篇 |
口腔科学 | 197篇 |
临床医学 | 849篇 |
内科学 | 3140篇 |
皮肤病学 | 424篇 |
神经病学 | 851篇 |
特种医学 | 421篇 |
外科学 | 1278篇 |
综合类 | 47篇 |
一般理论 | 1篇 |
预防医学 | 509篇 |
眼科学 | 201篇 |
药学 | 697篇 |
中国医学 | 17篇 |
肿瘤学 | 1230篇 |
出版年
2023年 | 84篇 |
2022年 | 171篇 |
2021年 | 304篇 |
2020年 | 192篇 |
2019年 | 243篇 |
2018年 | 298篇 |
2017年 | 234篇 |
2016年 | 280篇 |
2015年 | 292篇 |
2014年 | 392篇 |
2013年 | 480篇 |
2012年 | 735篇 |
2011年 | 743篇 |
2010年 | 409篇 |
2009年 | 346篇 |
2008年 | 624篇 |
2007年 | 653篇 |
2006年 | 540篇 |
2005年 | 556篇 |
2004年 | 550篇 |
2003年 | 520篇 |
2002年 | 539篇 |
2001年 | 213篇 |
2000年 | 197篇 |
1999年 | 194篇 |
1998年 | 137篇 |
1997年 | 100篇 |
1996年 | 90篇 |
1995年 | 46篇 |
1994年 | 66篇 |
1993年 | 62篇 |
1992年 | 137篇 |
1991年 | 120篇 |
1990年 | 133篇 |
1989年 | 123篇 |
1988年 | 94篇 |
1987年 | 103篇 |
1986年 | 106篇 |
1985年 | 101篇 |
1984年 | 84篇 |
1983年 | 79篇 |
1982年 | 32篇 |
1980年 | 25篇 |
1979年 | 50篇 |
1978年 | 31篇 |
1977年 | 24篇 |
1976年 | 22篇 |
1974年 | 36篇 |
1973年 | 21篇 |
1972年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Tasuku Ogita Rosaly Vallejo Manaois Manabu Wakagi Tomoyuki Oki Yuko Takano Ishikawa 《International journal of food sciences and nutrition》2016,67(4):431-440
Two cultivars of Japanese parsley were harvested in different seasons; their antioxidant capacities were evaluated by oxygen radical absorbance capacity (ORAC) methods, and the contents of hydrophilic and lipophilic antioxidants were compared. Japanese parsley possessed potent antioxidant capacities both in hydrophilic and lipophilic extracts when evaluated by ORAC methods. LC/MS/MS analyses revealed that chlorogenic acid and four kinds of quercetin glycosides were major antioxidants in the hydrophilic extract. Lutein was the main contributor to the antioxidant capacity of the lipophilic extract. Antioxidant capacities of the hydrophilic extracts of both cultivars tended to be higher in winter because of the increase in the contents of chlorogenic acid and quercetin glycosides. An obvious trend in the lipophilic antioxidant capacities or lutein contents was not observed irrespective of the cultivar. 相似文献
3.
4.
Yuko Suzuki 《Brain structure & function》2006,211(3):189-196
The expression of insulin-like growth factor binding proteins (IGFBPs) in the developing mouse submandibular and von Ebner’s glands was determined by in situ hybridization and by an immunohistochemical method. In the submandibular glands, IGFBP-2 and IGFBP-4 mRNAs were expressed in the terminal end-buds (TEB) at E13–E17, concomitant with epithelial branching. IGFBP-3 mRNA was expressed in the mesenchyme surrounding the TEB; and IGFBP-5 mRNA, in the ducts. At E17, IGFBP-5 mRNA expression was observed not only in the ducts but also in the TEB. Similarly, IGFBP-4 mRNA expression was observed not only in the TEB but also in the mesenchyme. After birth, IGFBP-4 expression was observed only in the connective tissue and disappeared by P14. That of IGFBP-7 appeared at P1 and was observed in the connective tissue until P21. The IGFBP-5 mRNA expression pattern after birth was the same as that seen at E17, but at P21 IGFBP-5 was immunohistochemically expressed only in the duct. The mRNA level of IGFBP-2 expression at postnatal days was weak, but its protein was detected in the ducts and acini at P14–P21. In von Ebner’s glands, which appeared at the base of the circumvallate papillae at E17, only IGFBP-2 and IGFBP-4 mRNAs were expressed in the ducts and acini. Postnatally, IGFBP-4 was substituted by IGFBP-5 in the same region. Immunohistochemically, IGFBP-5 and IGFBP-2 were expressed in the ducts and acini at P14–P21. Throughout the study, IGFBP-6 was not detected by in situ hybridization, the immunoreactivity for it was observed in the nerve fibers of submandibular and von Ebner’s glands. These data support a role for these molecules as local mediators of salivary growth and differentiation. 相似文献
5.
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
6.
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
7.
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
8.
9.
Yuko Kamio Yurika Saito Naoki Utoguchi Masuo Kondoh Naoya Koizumi Makiko Fujii Yoshiteru Watanabe 《Journal of controlled release》2005,102(3):563-568
Some physiological substances, including acetylcholine and nitric oxide, are useful candidates for stimulation of intestinal absorption of drugs. In the present study, we elucidated the ability of epinephrine (Epi) to stimulate the intestinal absorption of drugs. We evaluated the ability of Epi to enhance absorption of macromolecules using dextran (Mw 4000 Da), which is poorly absorbed from the intestine, as a model compound in situ in a closed loop of the rat jejunum. Treatment of the jejunum with Epi resulted in significant increase in absorption of dextran in a dose-dependent fashion. The area under the curve (AUC) from 0 to 4 h in the Epi-treated jejunum was 13-fold higher than that in the vehicle-treated jejunum. The absorption-enhancing activity of Epi was 40-fold higher than that of caprate, a clinically used absorption-enhancer of drugs. In the experimental conditions used in this study, histological injury of the mucosa and perturbation of the mucosal membrane were not observed in the Epi-treated jejunum. Treatment with an antagonist of alpha-adrenergic receptors attenuated the stimulation of intestinal absorption by Epi, and treatment with an agonist of alpha-adrenergic receptors resulted in enhancement of intestinal absorption. While an antagonist of beta-adrenergic receptors enhanced the absorption-enhancing effect of Epi, an agonist of beta-adrenergic receptors stimulated intestinal absorption. These results indicate that stimulation of adrenergic receptors may be a novel strategy for intestinal absorption of drugs. 相似文献
10.