全文获取类型
收费全文 | 37737篇 |
免费 | 3358篇 |
国内免费 | 2596篇 |
专业分类
耳鼻咽喉 | 394篇 |
儿科学 | 464篇 |
妇产科学 | 443篇 |
基础医学 | 4191篇 |
口腔科学 | 722篇 |
临床医学 | 4889篇 |
内科学 | 5615篇 |
皮肤病学 | 345篇 |
神经病学 | 1922篇 |
特种医学 | 1190篇 |
外国民族医学 | 19篇 |
外科学 | 3997篇 |
综合类 | 6729篇 |
现状与发展 | 9篇 |
一般理论 | 11篇 |
预防医学 | 2722篇 |
眼科学 | 926篇 |
药学 | 3749篇 |
27篇 | |
中国医学 | 2163篇 |
肿瘤学 | 3164篇 |
出版年
2024年 | 125篇 |
2023年 | 604篇 |
2022年 | 1529篇 |
2021年 | 1851篇 |
2020年 | 1426篇 |
2019年 | 1185篇 |
2018年 | 1292篇 |
2017年 | 1160篇 |
2016年 | 1114篇 |
2015年 | 1606篇 |
2014年 | 1887篇 |
2013年 | 1804篇 |
2012年 | 2684篇 |
2011年 | 3000篇 |
2010年 | 2014篇 |
2009年 | 1637篇 |
2008年 | 2049篇 |
2007年 | 2126篇 |
2006年 | 2070篇 |
2005年 | 1909篇 |
2004年 | 1416篇 |
2003年 | 1355篇 |
2002年 | 1202篇 |
2001年 | 972篇 |
2000年 | 936篇 |
1999年 | 844篇 |
1998年 | 551篇 |
1997年 | 521篇 |
1996年 | 385篇 |
1995年 | 406篇 |
1994年 | 306篇 |
1993年 | 199篇 |
1992年 | 259篇 |
1991年 | 210篇 |
1990年 | 167篇 |
1989年 | 140篇 |
1988年 | 157篇 |
1987年 | 123篇 |
1986年 | 98篇 |
1985年 | 76篇 |
1984年 | 54篇 |
1983年 | 33篇 |
1982年 | 25篇 |
1981年 | 22篇 |
1980年 | 24篇 |
1979年 | 38篇 |
1977年 | 16篇 |
1973年 | 11篇 |
1972年 | 10篇 |
1971年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
人体蠕形螨的生物学研究 总被引:4,自引:0,他引:4
用透明胶带法观察蠕形螨在人体面部的寄生、逸出及其在体外的存活能力。结果表明:毛囊蠕形螨(Demod-exfoliculorum,D.f.)主要以颚体朝向毛囊底部寄生,且常常有多条群居现象,而皮脂蠕形螨,(Demodexbrevis,D.b.)一般为单条独居生活。两种人体蠕形螨昼夜均可主动爬出毛囊口出现在皮肤表面,D.f.以白天1000~1800为逸出高峰;D.b.则以夜间2200~200逸出最多。此外,蠕形螨在体外有较强的活动力和存活力。透明胶带法在人体蠕形螨的流行病学调查和生物学研究方面具有较高的应用价值 相似文献
2.
Erik D Skarsgard Ying C MacNab Zhenguo Qiu Ruth Little Shoo K Lee 《Journal of perinatology》2005,25(5):315-319
OBJECTIVE: Outcomes analysis in congenital diaphragmatic hernia (CDH) requires a validated risk-adjustment tool. The purpose of this study was to use the Canadian Neonatal Network (CNN) database to validate the Score for Neonatal Acute Physiology, Version II (SNAP-II) for prediction of mortality among CDH infants admitted to a neonatal intensive care unit (NICU), and to compare this to the predictive equation recently developed by the Congenital Diaphragmatic Hernia Study Group (CDHSG). STUDY DESIGN: Infants with CDH in the CNN database were identified. Bivariate and multivariable logistic regression models were used to identify risk factors predictive of mortality. Model predictive performance and calibration were assessed using the area under the receiver operator characteristic curve and the technique of Hosmer-Lemeshow, respectively, and compared with the CDHSG predictive equation. RESULTS: There were 88 patients with CDH among 19,507 admissions to CNN hospitals. The mortality rate among CDH patients surviving to NICU admission was 17%, and 12.5% received extracorporeal membrane oxygenation therapy. Gestational age and admission SNAP-II score predicted mortality. Model predictive performance and calibration were optimized with these variables combined. The CDHSG equation was equally predictive of mortality, but was only marginally calibrated. CONCLUSIONS: SNAP-II is highly predictive of mortality among patients with CDH, and can be used to risk-adjust these patients. 相似文献
3.
4.
5.
The influence of sex steroids and the dopaminergic system on the in vivo modulation of prolactin (PRL) mRNA levels was investigated by quantitative in situ hybridization in the male rat anterior pituitary gland. In situ hybridization was performed using a [35S]-labeled cDNA probe encoding PRL. Orchiectomy performed 14 days earlier did not modify PRL mRNA levels. In orchiectomized rats treatment with the dopaminergic agonist bromocriptine for 14 days decreased PRL mRNA levels by 30%, while in intact animals the same treatment did not induce any changes in PRL mRNA levels. Administration of the dopamine D2 receptor antagonist haloperidol in both intact and orchiectomized rats induced a 4-fold increase in mRNA levels. Administration of dihydrotestosterone to orchiectomized animals which had been treated or not with haloperidol or bromocriptine did not modify PRL mRNA levels. In orchiectomized animals administration of 17ß-estradiol (0.25 μg twice daily) for 14 days caused a 4-fold increase in amounts of PRL mRNA. Administration of bromocriptine to 17ß-estradiol-treated animals induced a 15% decrease of PRL mRNA levels compared to those obtained by 17ß-estradiol administered alone. The concomitant administration of 17ß-estradiol and haloperidol resulted in a 50% increase in PRL mRNA levels compared to those measured in animals treated with haloperidol alone. The present results clearly demonstrate that in vivo estrogen as well as dopamine-mediated mechanisms play a regulatory role in PRL mRNA levels in the male rat. 相似文献
6.
Twenty cases of microglandular hyperplasia (MGH) of the uterine cervix and 14 cases of low-grade (nuclear) mucinous adenocarcinoma of the endometrium (MA) were compared morphologically and immunohistochemically. Subnuclear vacuoles were seen in 10 cases of MGH but were absent in all MA. Luminal squamous metaplasia was seen in only 10% of MGH cases versus 65% of MA cases. Stromal foam cells were present in 36% of MA but were absent in MGH cases. Both MGH and MA had minimal variation in nuclear size and inconspicuous nucleoli. As many as 8 mitoses/10 high-power fields (MF/10 HPF) were found in MA compared with 3 or fewer MF/10 HPF in MGH. Vimentin was expressed in 90% of MA but was absent in MGH. A significantly higher percentage of MA cells stained with MIB-1 than did those of MGH (mean 11% versus 0.5%). Both MA and MGH lacked CEA and p53 staining, whereas both had variable expression of ER and PR with no significant differences except that PR was absent in 40% of MGH cases. Our findings indicate that in the differential diagnosis of MGH versus MA, the presence of subnuclear vacuoles favors the former, whereas luminal squamous metaplasia, stromal foam cells, mitotic activity, vimentin expression, and MIB-1 expression favor the latter. 相似文献
7.
The first 150 words of the full text of this article appear below. Key points. . . [Full Text of this Article]
Nerve agents
AChE inhibitionOther cholinesterasesPhysical propertiesLatency and toxicityPharmacological propertiesClinical manifestationsTreatmentPyridostigmineAtropinePralidoxime
- Chemical personal protective equipment must be wornwhen in contact with contaminated casualties.
- Recognizing theclinical features of chemical warfare agent poisoning allowssupportive treatment and appropriate antidotes to be promptlyadministered.
- The mnemonic DUMBELS describes the muscarinicfeatures of the nerve agent poisoning toxidrome.
- There areeffective antidotes for poisoning with nerve agents, blood agents(metabolic poisons), botulinum toxin and kolokol-1.
- There areno specific antidotes for blistering agents (vesicants) andchoking agents.