全文获取类型
收费全文 | 243793篇 |
免费 | 18238篇 |
国内免费 | 4929篇 |
专业分类
耳鼻咽喉 | 1177篇 |
儿科学 | 4205篇 |
妇产科学 | 5326篇 |
基础医学 | 47499篇 |
口腔科学 | 6426篇 |
临床医学 | 28382篇 |
内科学 | 42641篇 |
皮肤病学 | 3314篇 |
神经病学 | 18593篇 |
特种医学 | 8976篇 |
外国民族医学 | 9篇 |
外科学 | 23955篇 |
综合类 | 10181篇 |
现状与发展 | 47篇 |
一般理论 | 11篇 |
预防医学 | 13067篇 |
眼科学 | 3067篇 |
药学 | 19748篇 |
49篇 | |
中国医学 | 11247篇 |
肿瘤学 | 19040篇 |
出版年
2024年 | 770篇 |
2023年 | 8723篇 |
2022年 | 12997篇 |
2021年 | 14018篇 |
2020年 | 14319篇 |
2019年 | 9207篇 |
2018年 | 9375篇 |
2017年 | 10120篇 |
2016年 | 10452篇 |
2015年 | 11556篇 |
2014年 | 19573篇 |
2013年 | 15957篇 |
2012年 | 13533篇 |
2011年 | 12282篇 |
2010年 | 12873篇 |
2009年 | 11892篇 |
2008年 | 7014篇 |
2007年 | 6956篇 |
2006年 | 5880篇 |
2005年 | 5021篇 |
2004年 | 4336篇 |
2003年 | 4175篇 |
2002年 | 3953篇 |
2001年 | 3952篇 |
2000年 | 3546篇 |
1999年 | 3645篇 |
1998年 | 2745篇 |
1997年 | 2194篇 |
1996年 | 2329篇 |
1995年 | 1936篇 |
1994年 | 1586篇 |
1993年 | 1251篇 |
1992年 | 1580篇 |
1991年 | 1536篇 |
1990年 | 1498篇 |
1989年 | 1341篇 |
1988年 | 1445篇 |
1987年 | 1128篇 |
1986年 | 935篇 |
1985年 | 828篇 |
1984年 | 971篇 |
1983年 | 825篇 |
1982年 | 819篇 |
1981年 | 782篇 |
1980年 | 646篇 |
1979年 | 503篇 |
1978年 | 496篇 |
1977年 | 428篇 |
1976年 | 434篇 |
1974年 | 335篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
33.
34.
35.
A study was undertaken of all drowning deaths that occurred over a 30-year period from 1988 to 2017 in the urban section of the River Torrens, Adelaide, South Australia, an augmented waterway that runs through the central business district. Autopsy records from Forensic Science South Australia (FSSA) were reviewed. There were 34 drownings (0–5 cases/yr) with 28 males and 6 females (M;F = 4.6:1), with an age range for males of 18-76yrs (mean 42.0; SD 18.0) and for females of 20-84yrs (mean 69.3; SD 24.5). There were 15 (44%) accidents, 11 (32%) suicides, 1 (3%) homicide and 7 (21%) undetermined. Of the 22 cases during or after 1994 with complete toxicology reports, 10 (45%) had a blood alcohol concentration (BAC) of greater than 0.05% (g/100 mL) with an illicit substance detected in 4 (18%) cases: (MDMA (3,4-methylenedioxymethamphetamine), methylamphetamine and THC (delta-9-tetrahydrocannabinol) acid). The presence of various therapeutic drugs was also detected in 10 cases (45%) including temazepam, fluoxetine, diazepam, olanzapine, amitriptyline, carbamazepine, codeine, citalopram and valproate. Although the numbers of cases were not high, the urban portion of the River Torrens had a much higher number of drowning events per kilometre compared to other inland waterways in South Australia such as the Murray River. This is most likely due to the vulnerability that exists for intoxicated individuals in the city from falls into the water and to the availability of the river as a means of suicide to members of the adjacent urban population. 相似文献
36.
37.
目的 分析H型高血压患者的舌面诊图像颜色参数特征,探讨H型高血压患者的舌诊、面诊变化规律。方法 运用上海中医药大学自行研制的Smart TCM-1型中医舌面一体仪,采集高血压患者舌面诊图像,提取特征参数,分析健康对照组、H型高血压组与非H型高血压组患者舌面颜色参数特征。结果 ①在舌色各项参数中,H型高血压组舌尖部R值、B值、V值均显著小于健康对照组(P < 0.01);非H型高血压组舌尖部B值显著小于健康对照组(P < 0.01),S值较健康对照组显著增大(P < 0.05);H型高血压组舌尖部R、V值均明显小于非H型高血压组(P < 0.05)。在舌苔各项参数中,H型高血压组舌中H值、V值均明显小于健康对照组(P < 0.05);非H型高血压组舌中V值、舌右V值均显著小于健康对照组(P < 0.01);H型高血压组舌中H值明显小于非H型高血压组(P < 0.05),右侧舌苔S值明显大于非H型高血压组(P < 0.05)。②H型高血压组面色参数鼻G值、下颌G值、口唇R值、口唇V值均明显小于健康对照组(P < 0.05);非H型高血压组前额H值、目眶H值、脸颊H值、鼻H值、下颌H值、整体H值均明显大于健康对照组(P < 0.05);H型高血压组前额H值、目眶G值、目眶H值、脸颊H值、鼻G值、鼻H值、下颌R值、下颌G值、下颌H值、下颌V值、口唇R值、口唇G值、口唇V值、整体R值、整体G值、整体H值、整体V值均明显小于非H型高血压组(P < 0.05)。结论 H型高血压患者苔色偏黄,以舌中部为主,且舌右侧黄苔积聚较明显;H型高血压患者面色为黄中带红,口唇、下颌部更为晦暗。H型高血压患者的舌、面诊特征参数的变化,与高血压病阳亢湿盛病机相符。 相似文献
38.
《Drug metabolism and pharmacokinetics》2019,34(5):308-316
LC-MS quantification of drug metabolites is sometimes impeded by the availability of internal standards that often requires customized synthesis and/or extensive purification. Although isotopically labeled internal standards are considered ideal for LC-MS/MS based quantification, de novo synthesis using costly isotope-enriched starting materials makes it impractical for early stage of drug discovery. Therefore, quick access to these isotope-enriched compounds without chemical derivatization and purification will greatly facilitate LC-MS/MS based quantification. Herein, we report a novel 18O-labeling technique using metabolizing enzyme carboxylesterase (CES) and its potential application in metabolites quantification study. Substrates of CES typically undergo a two-step oxygen exchange with H218O in the presence of the enzyme, generating singly- and doubly-18O-labeled carboxylic acids; however, unexpected hydrolytic behavior was observed for three of the test compounds – indomethacin, piperacillin and clopidogrel. These unusual observations led to the discovery of several novel hydrolytic mechanisms. Finally, when used as internal standard for LC-MS/MS based quantification, these in situ labeled compounds generated accurate quantitation comparable to the conventional standard curve method. The preliminary results suggest that this method has potential to eliminate laborious chemical synthesis of isotope-labeled internal standards for carboxylic acid-containing compounds, and can be developed to facilitate quantitative analysis in early-stage drug discovery. 相似文献
39.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2022,32(12):2883-2889
Background and aimsCoronary artery disease (CAD) is the principal cause of death in individuals with non-alcoholic fatty liver disease (NAFLD). The aim of this study was to use genetic epidemiology to study the association between de novo lipogenesis (DNL), one of the major pathways leading to NAFLD, and CAD risk.Methods and resultsDNL susceptibility genes were used as instruments and selected using three approaches: 1) genes that are associated with both high serum triglycerides and low sex hormone-binding globulin, both downstream consequences of DNL (unbiased approach), 2) genes that have a known role in DNL (biased approach), and 3) genes that have been associated with serum fatty acids, used as a proxy of DNL. Gene-CAD effect estimates were retrieved from the meta-analysis of CARDIoGRAM and the UK Biobank (~76014 cases and ~264785 controls). Effect estimates were clustered using a fixed-effects meta-analysis. Twenty-two DNL susceptibility genes were identified by the unbiased approach, nine genes by the biased approach and seven genes were associated with plasma fatty acids. Clustering of genes selected in the unbiased and biased approach showed a statistically significant association with CAD (OR:1.016, 95%CI:1.012; 1.020 and OR:1.013, 95%CI:1.007; 1.020, respectively), while clustering of fatty acid genes did not (OR:1.004, 95%CI:0.996–1.011). Subsequent exclusion of potential influential outliers did reveal a statistically significant association (OR:1.009, 95%CI:1.000; 1.018).ConclusionsDNL susceptibility genes are associated with an increased risk of CAD. These findings suggest that DNL may be involved in the pathogenesis of CAD and favor further development of strategies that target NAFLD through DNL. 相似文献
40.
《Vaccine》2015,33(41):5365-5370
Current live attenuated vaccines for control of Salmonella in poultry persist in the ceca and may persist in the environment. In this paper we report the construction and characterization of the vaccine efficacy of a Salmonella mutant strain with inducible mviN expression and rapid clearance from the host. The mutant was effective in oral immunization of the broiler chicken host against a virulent Salmonella oral challenge strain, having a mean 7 × 106 CFU/g in the ceca of unvaccinated controls compared to a mean 2 × 103 CFU/g in the ceca of vaccinated chickens at 4 weeks post-challenge (6 weeks of age). The mutant strain also demonstrated immunogenicity, reduced organ colonization, and rapid clearance in broiler chickens within 3 weeks of inoculation. 相似文献