全文获取类型
收费全文 | 45351篇 |
免费 | 5699篇 |
国内免费 | 846篇 |
专业分类
耳鼻咽喉 | 165篇 |
儿科学 | 1370篇 |
妇产科学 | 1047篇 |
基础医学 | 2858篇 |
口腔科学 | 1212篇 |
临床医学 | 5465篇 |
内科学 | 9885篇 |
皮肤病学 | 448篇 |
神经病学 | 3083篇 |
特种医学 | 1063篇 |
外国民族医学 | 1篇 |
外科学 | 4395篇 |
综合类 | 4160篇 |
现状与发展 | 8篇 |
一般理论 | 9篇 |
预防医学 | 8674篇 |
眼科学 | 648篇 |
药学 | 3382篇 |
26篇 | |
中国医学 | 330篇 |
肿瘤学 | 3667篇 |
出版年
2024年 | 102篇 |
2023年 | 1151篇 |
2022年 | 1357篇 |
2021年 | 2785篇 |
2020年 | 2680篇 |
2019年 | 2496篇 |
2018年 | 2427篇 |
2017年 | 2235篇 |
2016年 | 2235篇 |
2015年 | 2046篇 |
2014年 | 3536篇 |
2013年 | 4308篇 |
2012年 | 2550篇 |
2011年 | 2804篇 |
2010年 | 2100篇 |
2009年 | 2078篇 |
2008年 | 2113篇 |
2007年 | 1909篇 |
2006年 | 1685篇 |
2005年 | 1474篇 |
2004年 | 1188篇 |
2003年 | 980篇 |
2002年 | 824篇 |
2001年 | 764篇 |
2000年 | 590篇 |
1999年 | 473篇 |
1998年 | 443篇 |
1997年 | 376篇 |
1996年 | 302篇 |
1995年 | 284篇 |
1994年 | 235篇 |
1993年 | 237篇 |
1992年 | 177篇 |
1991年 | 146篇 |
1990年 | 120篇 |
1989年 | 104篇 |
1988年 | 92篇 |
1987年 | 80篇 |
1986年 | 62篇 |
1985年 | 84篇 |
1984年 | 67篇 |
1983年 | 25篇 |
1982年 | 45篇 |
1981年 | 31篇 |
1980年 | 28篇 |
1979年 | 19篇 |
1978年 | 10篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1974年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Dana Franzen-Klein Mark Jankowski Charlotte L. Roy Hoa Nguyen-Phuc Da Chen Lorin Neuman-Lee 《Journal of toxicology and environmental health. Part A》2020,83(2):45-65
ABSTRACTDomestic chickens (Gallus gallus domesticus) were exposed to imidacloprid by gavage once daily for 7 consecutive days at 0, 0.03, 0.34, 3.42, 10.25, and 15.5 mg/kg/day (n = 20 per group; 5 6-week-old males, 5 6-week-old females, 5 9-week-old males, and 5 9-week-old females). The severity and duration of neurobehavioral abnormalities were recorded. Components of the innate and adaptive immune system were assessed with 7 standard functional assays. Temporary neurobehavioral abnormalities were observed in a dose-dependent manner, including muscle tremors, ataxia, and depressed mentation. Based upon mean clinical severity scores, the no observed adverse effect level (NOAEL) was 3.42 mg/kg/day, and the lowest observed adverse effect level (LOAEL) was 10.25 mg/kg/day. The effective dose value for the presence of any neurobehavioral abnormalities in 50% of the test group (ED50) was 4.62 ± 0.98 mg/kg/day. The ED50 for an adjusted score that included both severity and duration of neurobehavioral abnormalities was 11.24 ± 9.33 mg/kg/day. These ED50 values are equivalent to a 1 kg bird ingesting 29 or 70 imidacloprid treated soybean seeds respectively. Immunotoxicity was not documented, possible causes include the assays were insensitive, relevant immune functions were not examined, or imidacloprid is not immunotoxic at this dosing schedule in this species. Neurobehavioral abnormalities were a more sensitive indicator of the sublethal effects of imidacloprid than immunotoxicity. 相似文献
22.
Factors predicting the development of pressure ulcers in an at‐risk population who receive standardized preventive care: secondary analyses of a multicentre randomised controlled trial 下载免费PDF全文
23.
24.
目的 研究缺血性脑血管病患者脑微出血(CMB)危险因素及其对抗血小板单药治疗的影响。方法 选取2018年1月至2018年6月该院神经内科接受抗血小板单药治疗的急性缺血性脑血管病患者300例为样本,入院后采集基本资料并完善相关检查,根据梯度回波T2*加权成像(GRE-T2*WI)检查结果将患者分为CMB组(176例)和非CMB组(124例),均给予抗血小板聚集治疗,比较两组临床资料及治疗1年内再发梗死、脑出血和病死率,分析影响CMB发病的危险因素以及CMB对抗血小板单药治疗的影响。结果 高龄、高血压、肥胖、脑卒中病史、ACI和脑白质疏松为CMB发生的危险因素(P<0.05)。CMB组和非CMB组抗血小板单药治疗期间脑出血率分别为14.20%和6.45%,差异有统计学意义(P<0.05)。轻度组、中度组和重度组脑出血率分别为9.18%、10.64%和35.48%,差异有统计学意义(P<0.05)。不同部位CMB患者抗血小板单药治疗期间再发脑梗死、脑出血及病死率比较,差异无统计学意义(P>0.05)。结论 高龄、高血压、肥胖、脑卒中病史、ACI及脑白质疏松为缺血性脑血管疾病合并CMB的危险因素。CMB可导致抗血小板单药治疗期间脑出血风险增加,重度CMB者更甚。 相似文献
25.
26.
27.
This study evaluated the genetic variation of 17 autosomal short tandem repeat (STR) loci included in the PowerPlex® 18D Kit. Samples of 562 unrelated healthy Lahu individuals living in Yunnan Province in southwestern China were investigated. The data were analyzed to provide information on allele frequencies and other statistical parameters relevant to the forensic population. Of the 17 loci, 16 reached the Hardy–Weinberg equilibrium after Bonferroni correction. A total of 176 alleles were identified in 17 STR loci, and allele frequencies ranged from 0.000 890 to 0.578 292. The combined discrimination power (CPD) and probability of excluding paternity (CPE) of the 17 STR loci were 0.999 999 999 999 999 999 489 and 0.999 998 301 753 122. The genetic relationships among 28 populations were also estimated. 相似文献
28.
《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(10):1030-1039
Background and aimThis network meta-analysis (NMA) compares the effects of different types of olive oil (OO) on cardiovascular risk factors.Methods and resultsLiterature search was conducted on three electronic databases (Medline, Web of Science, and Cochrane Central). Inclusion criteria: Randomized controlled trials (RCTs) (≥3 weeks duration of intervention) comparing at least two of the following types of OO: refined OO (ROO), mixed OO (MOO), low phenolic (extra) virgin OO (LP(E)VOO), and high phenolic (extra) virgin OO (HP(E)VOO). Random-effects NMA was performed for seven outcomes; and surface under the cumulative ranking curve (SUCRA) was estimated, using an analytical approach (P-score). Thirteen RCTs (16 reports) with 611 mainly healthy participants (mean age: 26–70 years) were identified. No differences for total cholesterol, HDL-cholesterol, triacylglycerols, and diastolic blood pressure were observed comparing ROO, MOO, LP(E)VOO and HP(E)VOO. HP(E)VOO slightly reduce LDL-cholesterol (LDL-C) compared to LP(E)VOO (mean difference [MD]: −0.14 mmol/L, 95%–CI: −0.28, −0.01). Both, HP(E)VOO and LP(E)VOO reduces SBP compared to ROO (range of MD: −2.99 to −2.87 mmHg), and HP(E)VOO may improve oxidized LDL-cholesterol (oxLDL-C) compared to ROO (standardized MD: −0.68, 95%–CI: −1.31, −0.04). In secondary analyses, EVOO may reduce oxLDL-C compared to ROO, and a dose-response relationship between higher intakes of phenolic compounds from OO and lower SBP and oxLDL-C values was detected. HP(E)VOO was ranked as best treatment for LDL-C (P-score: 0.83), oxLDL-C (0.88), and SBP (0.75).ConclusionsHP(E)VOO may improve some cardiovascular risk factors, however, public health implications are limited by overall low or moderate certainty of evidence. 相似文献
29.
《Annals of hepatology》2019,18(4):563-570
Introduction and ObjectivesNonalcoholic fatty liver disease (NAFLD) can be considered one of the most common causes of liver disease in our days and is regarded as one of the newest vascular risk factors for cerebrovascular and other neurological diseases.Materials and methodsWe studied a group of neurological outpatients, divided into two homogenous groups based on the presence or absence of NAFLD.Results and conclusionsWe testified an independent relationship between NAFLD and common vascular risk factors (age, sex, educational level, BMI, cholesterol and lipid assessment, Hb1ac). At the same time, we ascertained an independent relationship between NAFLD and more recently recognized vascular risk factors, such as lack of folate, vitamin B12 and vitamin D-OH25, and increased levels of homocysteine. Finally, we have documented that NAFLD showed worse executive and frontal functions, and behavioral changes, such as depressive mood and anxiety, and apathy. 相似文献
30.
Chien-Hua Tseng Ben-Jei Tsuang Chun-Ju Chiang Kai-Chen Ku Jeng-Sen Tseng Tsung-Ying Yang Kuo-Hsuan Hsu Kun-Chieh Chen Sung-Liang Yu Wen-Chung Lee Tsang-Wu Liu Chang-Chuan Chan Gee-Chen Chang 《Journal of thoracic oncology》2019,14(5):784-792