全文获取类型
收费全文 | 37227篇 |
免费 | 1994篇 |
国内免费 | 112篇 |
专业分类
耳鼻咽喉 | 447篇 |
儿科学 | 2239篇 |
妇产科学 | 752篇 |
基础医学 | 4790篇 |
口腔科学 | 840篇 |
临床医学 | 2620篇 |
内科学 | 7548篇 |
皮肤病学 | 909篇 |
神经病学 | 1983篇 |
特种医学 | 824篇 |
外科学 | 5041篇 |
综合类 | 1334篇 |
一般理论 | 15篇 |
预防医学 | 2219篇 |
眼科学 | 1607篇 |
药学 | 3592篇 |
中国医学 | 292篇 |
肿瘤学 | 2281篇 |
出版年
2023年 | 256篇 |
2022年 | 692篇 |
2021年 | 1207篇 |
2020年 | 667篇 |
2019年 | 905篇 |
2018年 | 1112篇 |
2017年 | 762篇 |
2016年 | 1004篇 |
2015年 | 1042篇 |
2014年 | 1432篇 |
2013年 | 1839篇 |
2012年 | 2550篇 |
2011年 | 2551篇 |
2010年 | 1434篇 |
2009年 | 1286篇 |
2008年 | 1861篇 |
2007年 | 1786篇 |
2006年 | 1825篇 |
2005年 | 1440篇 |
2004年 | 1436篇 |
2003年 | 1231篇 |
2002年 | 1037篇 |
2001年 | 828篇 |
2000年 | 871篇 |
1999年 | 732篇 |
1998年 | 312篇 |
1997年 | 219篇 |
1996年 | 230篇 |
1995年 | 220篇 |
1994年 | 183篇 |
1993年 | 155篇 |
1992年 | 500篇 |
1991年 | 408篇 |
1990年 | 432篇 |
1989年 | 400篇 |
1988年 | 357篇 |
1987年 | 356篇 |
1986年 | 349篇 |
1985年 | 323篇 |
1984年 | 262篇 |
1983年 | 220篇 |
1979年 | 230篇 |
1978年 | 148篇 |
1977年 | 181篇 |
1976年 | 141篇 |
1975年 | 172篇 |
1974年 | 182篇 |
1973年 | 182篇 |
1972年 | 173篇 |
1971年 | 161篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Debisri Sarkar Archana Sharma Geeta Talukder 《Environmental and molecular mutagenesis》1996,28(2):121-126
Dietary consumption of green vegetables has been associated with protection against mutagenic and clastogenic activity of genotoxicants. Chlorophyll, being present in all green plants, had earlier been suggested to be the principal factor involved. Mice were administered (i) crude aqueous extract of leaf of Indian spinach, Beta vulgaris L. var. benghalensis Hort., and equivalent amounts of (ii) chlorophyll extracted from the leaf; (iii) purified chlorophyll, (iv) chlorophyllin, a sodium-copper derivative of chlorophyll; daily for 7 days. On day 7, one set of mice from each treatment was administered potassium dichromate—a known metallic clastogen. The mice were sacrificed after 24 hours. Chromosome preparations were made from bone marrow following the usual colchicine-air dry-Giemsa schedule. The cytogenetic endpoints scored were chromosomal aberrations and damaged cells. Crude leaf extract and chlorophyllin were nonclastogenic and reduced the clastogenic effects of potassium dichromate to the control distilled water level. Chlorophyll alone, whether extracted from the leaf or obtained in commercially purified form, was clastogenic and could reduce the effects of the chromium salt only to its own level. The protective action of the crude leaf extract may be attributed to the total effect of the interaction between the different components within the leaf extract, in which the clastogenicity of chlorophyll had been neutralized. © 1996 Wiley-Liss, Inc. 相似文献
993.
Allicin, a molluscicidal component of garlic inhibited the activity of acetylcholinesterase, lactic dehydrogenase and alkaline phosphatase in in vivo and in vitro exposure against Lymnaea acuminata . It was observed that succinic dehydrogenase activity in the nervous tissue of Lymnaea acuminata was increased in in vivo treatment whereas with in vitro exposure, allicin caused no significant change in succinic dehydrogenase activity. The inhibition kinetics of these enzymes indicates that allicin caused an uncompetitive inhibition of AChE and a competitive inhibition of LDH and alkaline phosphatase. 相似文献
994.
Ursolic acid isolated from the leaves and stems of Duboisia myoporoides (Solanaceae) was bioassayed by leaf disc method for feeding deterrence using Spilosoma obliqua and Spodoptera litura as test insects. This compound was proved to be a potent antifeedant under laboratory conditions. Azadirachtin was used as standard. Ursolic acid produced 90.12% and 91.96% inhibition at 5000 ppm concentration, respectively, against S. obliqua and S. litura . 相似文献
995.
996.
Background: Reports indicate patients with feeding difficulties demonstrate signs of inflammation on biopsies, notably eosinophilia, but it is unknown whether mast cell density contributes to variety or volume limitation symptoms. The aim of our study was to evaluate eosinophil and mast cell density of EGD biopsies in pediatric patients with symptoms of decreased volume or variety of ingested foods. Methods: We conducted a single-center, retrospective chart review of EMRs for all new feeding clinic patients between 0 and 17 years of age. Patients were categorized by symptoms at the initial visit as well as eosinophil and mast cell densities in those with EGD biopsies. Ten patients were identified as controls. Results: We identified 30 patients each with volume and variety limitation. Antral mast cell density was increased in 32.1% of variety-limited patients, 37.5% of volume limited patients, and in no controls; Duodenal mast cell density was increased in 32.1% of variety-limited patients, 40.6% of volume-limited patients, and in no controls. Conclusions: In both variety- and volume-limited patients, antral and duodenal mast cell densities were increased. These associations warrant further investigation of the mechanism between mast cells and development of feeding difficulties, allowing more targeted pediatric therapies. 相似文献
997.
Sukhjinder Kaur Ashwani Kumar Singh Mrigank Honparkhe Ajeet Kumar Prahlad Singh Udeybir Singh 《亚太生殖杂志》2021,(3):127-136
Objective: To assess the effect of flaxseed supplementation on metabolic profile, endocrine concentrations, non-esterified fatty acids (NEFA), body composition ... 相似文献
998.
Sadhna Aggarwal Baldeep Singh Suresh C. Sharma Satya N. Das 《Indian journal of otolaryngology and head and neck surgery》2022,74(4):510
Oral squamous cell carcinoma (OSCC) is one of the most common (90%) types of oral carcinomas in the world. It is the 2nd most common and 3rd deadliest cancer in India. The lack of early detection marker is one of the major causes of worst prognosis. The vimentin belongs to intermediate filament family proteins which plays significant role in maintaining cellular integrity. Over-expression of vimentin has been widely reported in many epithelial cancers however the information regarding its prevalence in the oral cancers still needs further scientific intervention. The expression level of circulating vimentin protein in serum samples (n = 30) of oral submucous fibrosis (OSMF), OSCC patients and healthy controls were measured by performing ELISA. The serum level of vimentin was significantly higher in OSMF (p < 0.01) and OSCC (p < 0.003) patients as compared to healthy subjects. The circulating vimentin levels showed a gradual increase with increasing disease status (normal < OSMF < OSCC). Circulatory levels of vimentin may ba useful indicator of disease progression and as a suitable target for therapeutic intervention of oral submucous fibrosis and oral carcinoma. 相似文献
999.