全文获取类型
收费全文 | 406262篇 |
免费 | 45013篇 |
国内免费 | 21595篇 |
专业分类
耳鼻咽喉 | 3942篇 |
儿科学 | 6552篇 |
妇产科学 | 2335篇 |
基础医学 | 25106篇 |
口腔科学 | 7362篇 |
临床医学 | 48595篇 |
内科学 | 33168篇 |
皮肤病学 | 4930篇 |
神经病学 | 7621篇 |
特种医学 | 15614篇 |
外科学 | 33979篇 |
综合类 | 116573篇 |
现状与发展 | 93篇 |
预防医学 | 48485篇 |
眼科学 | 4773篇 |
药学 | 50545篇 |
669篇 | |
中国医学 | 45032篇 |
肿瘤学 | 17496篇 |
出版年
2025年 | 57篇 |
2024年 | 6135篇 |
2023年 | 6912篇 |
2022年 | 13980篇 |
2021年 | 17088篇 |
2020年 | 15265篇 |
2019年 | 8397篇 |
2018年 | 8295篇 |
2017年 | 11575篇 |
2016年 | 8616篇 |
2015年 | 15925篇 |
2014年 | 20394篇 |
2013年 | 26005篇 |
2012年 | 37230篇 |
2011年 | 39893篇 |
2010年 | 36111篇 |
2009年 | 31654篇 |
2008年 | 32468篇 |
2007年 | 31224篇 |
2006年 | 27366篇 |
2005年 | 21439篇 |
2004年 | 15152篇 |
2003年 | 12184篇 |
2002年 | 9256篇 |
2001年 | 8403篇 |
2000年 | 6279篇 |
1999年 | 2248篇 |
1998年 | 504篇 |
1997年 | 398篇 |
1996年 | 381篇 |
1995年 | 322篇 |
1994年 | 321篇 |
1993年 | 179篇 |
1992年 | 151篇 |
1991年 | 123篇 |
1990年 | 96篇 |
1989年 | 72篇 |
1988年 | 64篇 |
1987年 | 99篇 |
1986年 | 100篇 |
1985年 | 63篇 |
1984年 | 46篇 |
1983年 | 47篇 |
1982年 | 51篇 |
1965年 | 16篇 |
1959年 | 27篇 |
1958年 | 36篇 |
1957年 | 36篇 |
1956年 | 23篇 |
1955年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
131.
目的 探讨20例样本ABO血型抗原表达减弱的分子生物学机制。方法 采用微柱凝集法及盐水试管法进行ABO血型血清学鉴定;对ABO基因第1-7外显子及其上游启动子区域PCR产物直接测序进行基因分型。结果 11例样本通过家系分析可以确定其基因型(1例ABO*A2.01/ABO*B.01,1例ABO*A2.01/ABO*O01.01,1例A1.02/B3.04,2例B3.04/O.01.01、2例B3.02/O.01.02,4例Bw.12/O.01.01);3例样本在ABO基因启动子区域发生-35_-18位的碱基缺失,通过家系分析,提示该变异发生在B等位基因;1例样本在ABO基因启动子区域发生-119位C>T变异;1例样本发生第7外显子1054位点缺失碱基C;4例样本在ABO血型基因1-7外显子及其调控区域未发现变异。结论 启动子区域-119位C>T变异及Exon7 1054del变异可能是导致ABO血型抗原异常表达的新变异;部分ABO亚型可能与内含子异常或mRNA合成异常有关;本地区B亚型明显多于A亚型。 相似文献
132.
ZHU Yuan Yue ZHENG Rui Zhi WANG Gui Xia CHEN Li SHI Li Xin SU Qing XU Min XU Yu CHEN Yu Hong YU Xue Feng YAN Li WANG Tian Ge ZHAO Zhi Yun QIN Gui Jun WAN Qin CHEN Gang GAO Zheng Nan SHEN Fei Xia LUO Zuo Jie QIN Ying Fen HUO Ya Nan LI Qiang YE Zhen ZHANG Yin Fei LIU Chao WANG You Min WU Sheng Li YANG Tao DENG Hua Cong ZHAO Jia Jun CHEN Lu Lu MU Yi Ming TANG Xu Lei HU Ru Ying WANG Wei Qing NING Guang LI Mian LU Jie Li BI Yu Fang 《Biomedical and environmental sciences : BES》2021,34(1):9-18
Objective The relationship between serum uric acid(SUA)levels and glycemic indices,including plasma glucose(FPG),2-hour postload glucose(2 h-PG),and glycated hemoglobin(HbA1 c),remains inconclusive.We aimed to explore the associations between glycemic indices and SUA levels in the general Chinese population.Methods The current study was a cross-sectional analysis using the first follow-up survey data from The China Cardiometabolic Disease and Cancer Cohort Study.A total of 105,922 community-dwelling adults aged≥40 years underwent the oral glucose tolerance test and uric acid assessment.The nonlinear relationships between glycemic indices and SUA levels were explored using generalized additive models.Results A total of 30,941 men and 62,361 women were eligible for the current analysis.Generalized additive models verified the inverted U-shaped association between glycemic indices and SUA levels,but with different inflection points in men and women.The thresholds for FPG,2 h-PG,and HbA1 c for men and women were 6.5/8.0 mmol/L,11.0/14.0 mmol/L,and 6.1/6.5,respectively(SUA levels increased with increasing glycemic indices before the inflection points and then eventually decreased with further increases in the glycemic indices).Conclusion An inverted U-shaped association was observed between major glycemic indices and uric acid levels in both sexes,while the inflection points were reached earlier in men than in women. 相似文献
133.
目的 了解北极特殊环境对科考队员睡眠质量的影响.方法 应用匹兹堡睡眠质量指数(PSQI)量表对参加我国第9次北极科学考察的科考队员(131人)在出行前、北极考察期间、考察结束后的睡眠情况进行调查,并记录队员的入睡时间点、晨起时间点、入睡时间、睡眠时间.结果 共发放问卷131份,回收有效问卷88份.88名队员中男77名、女11名,年龄为22~50(48.1±17.9)岁,包括船员18人、科考队员70人.考察期间队员的中位晨起时间点比出行前早180 min,入睡时间长于出行前及考察结束3个月后[(45.23±25.84)min vs(18.45±14.34)min、(19.50±12.57)min,P均<0.01],夜晚睡眠时间短于出行前及考察结束3个月后[(6.83±2.24)h vs(8.36±1.45)h、(8.14±1.45)h,P均<0.01].根据PSQI量表评分,考察期间队员的睡眠质量下降、入睡时间延长、睡眠时间缩短、睡眠效率下降、催眠药物使用增加,与出行前相比差异均有统计学意义(P均<0.01).结论 极地极昼及低温环境显著影响北极科学考察时科考队员的睡眠节律,导致入睡时间延长、睡眠时间缩短、助眠药物使用增加,这可能影响到队员的工作状态. 相似文献
134.
LIU Nan GUAN Yi XUE Ling LI Bin YAO San Qiao 《Biomedical and environmental sciences : BES》2021,34(3):222-226
Case reports of lung disease among indiumexposed workers in Japan,the USA,and China over the past two decades have raised public concern about the toxicity of indium and indium compounds.Occupational exposure to indium compounds can result in potentially fatal indium lung disease,which is characterized by pulmonary alveolar proteinosis(PAP)and may progress to fibrosis,with or without emphysema[1]. 相似文献
135.
YANG Zhen Yu ZHANG Qian ZHAI Yi XU Tao WANG Yu Ying CHEN Bo Wen TANG Xue Jun YUAN Xiao Lin FANG Hong Yun ZHU Yan PANG Xue Hong WANG Shuo XU Juan LI Rui Li SI Xiang ZHAO Wen Hua 《Biomedical and environmental sciences : BES》2021,34(11):891-899
The main purpose of the National Nutrition and Health Systematic Survey for children 0-17 years of age in China (CNHSC) was to collect basic data on the nutrition, development, and health status for children in different regions across China using evidence-based, reliable, and cost-effective approaches. Children and their parents or guardians from seven regions (south, southwest, north, northwest, eastern, central, and northeast China) in China were recruited. A multi-stage stratified randomized sampling method was used. Two provinces were randomly sampled from each of the seven regions, from which one urban district and one rural country were also randomly sampled, resulting in a total of 28 survey counties/districts. Dietary surveys, health examinations, laboratory testing, and questionnaires were used to collect dietary intake, nutritional status, child development, and health status information. Nutrition, health, and lifestyle assessment of children and their parents was determined using the Knowledge Attitude Practice (KAP) survey. Greater than 100,000 children (38,000 children < 6 years of age and 66,000 children 6-17 years of age) completed the survey. The survey provided comprehensive data on child nutrition and health status for future studies and will serve as the basis for an integrated nutrition and health improvement strategies proposal for children in China. 相似文献
136.
YE Cheng Yin LI Jin Mei WU Jing Hua LI Zheng XIAO Juan YIN Xiao Yu WANG Da Hui XU Guo Zhang YANG Lei 《Biomedical and environmental sciences : BES》2021,34(8):641-645,中插6-中插12
With a global prevalence of 7.7 million, ischemic stroke (IS) is one of the leading causes of death and disability worldwide. In China, IS alone contributed to 69.6%? of stroke events and accounted for 37.1%? of the mortality/disability rate[1]. IS is a complex disease that is known to be associated?with?various?genetic?variants?and?clinical and lifestyle risk factors[2]. Genome -wide association studies (GWAS) provided evidence for the?occurrence?of?more?than?160?IS-associated?single nucleotide?polymorphisms?(SNPs).?In?terms?of?clinical risk factors, patients with a history of chronic diseases like hypertension, dyslipidemia, and diabetes mellitus, display a higher risk of developing IS. Among the various lifestyle components, leading a sedentary lifestyle, smoking, and having an unhealthy diet are known to be associated with the risk of IS. Thus, integration of various genetic, clinical, and lifestyle variables might prove to be highly beneficial in the prediction and prevention of IS?at?the?individual?level[3]. 相似文献
137.
TANG Chen FAN Chun GUO Dong Bei MA Xiu Juan CAI Qing Tao CHEN Xiao Xuan ZHANG Min LI Jia Yao AN Qiu Ying ZHAO Ran 《Biomedical and environmental sciences : BES》2021,34(8):656-661,中插17-中插22
Polybrominated diphenyl ethers (PBDEs) are a group of aromatic organic bromine compounds, which have been used in a broad array of polymeric materials (plastics, foams, resins, and adhesives) as brominated flame retardants. They are used in commercial and household products, including textiles, electronic equipment, airplanes, and automobiles, especially in China and the USA, because they are inexpensive with excellent flame-retardant effects[1]. During the past decade, over 14,000 tonnes of PBDEs have entered the market, and have become ubiquitous environmental contaminants[2]. 相似文献
138.
目的 通过测定乌司他丁与免疫球蛋白结合蛋白(Bip)在脑缺血再灌注模型大鼠血清、大脑皮层中的浓度,以及两者的体外结合实验、模拟分子对接模型,探讨两者之间的相互作用。方法将36只雄性SD大鼠随机分为两组。正常组(n=18)大鼠经静脉注射乌司他丁20万IU/kg作为对照。实验组(n=18)大鼠在建立大脑中动脉栓塞模型(MCAO)后随即静脉注射乌司他丁20万IU/kg。采用酶标仪法、ELISA法分别测定乌司他丁及Bip在大鼠脑缺血后05、3、24 h中血清、大脑皮层中的浓度。通过乌司他丁与Bip的结合实验计算两者结合率,并利用软件模拟乌司他丁与Bip的分子对接模型。结果在患侧大脑皮层中,实验组乌司他丁浓度在3 h升高,24 h下降,而Bip浓度则在3 h中下降,24 h升高。乌司他丁与Bip的结合率为44%~62%,分子对接结果显示乌司他丁与Bip中的残基可形成范德华力及共轭作用,两者可形成不稳定复合物。结论在缺血大脑皮质中乌司他丁可与Bip形成不稳定复合物,其可能通过影响Bip的表达而在脑缺血再灌注中发挥着一定作用。 相似文献
139.
抗胆碱能药物在临床应用历史悠久,最初被应用于呼吸系统疾病的治疗。目前,抗胆碱能药物作为重要的术前用药,其术前应用是保证临床麻醉安全实施的重要措施,在促进患者术后快速康复中扮演重要角色。目前抗胆碱能药物种类较多,作用机制不同,术前规范并合理使用抗胆碱能药物可防范麻醉及手术因素所致的风险,保证患者围手术期安全,提高围手术期麻醉管理质量。为进一步规范术前抗胆碱能药物使用,受广东省医学会麻醉学分会的委托,本专家共识邀请省内相关领域麻醉专家,根据国内外最新研究进展和专家共识及指南,结合各中心术前应用抗胆碱能药物的临床实践经验,从抗胆碱能药物在临床麻醉中的应用及在围手术期的应用、麻醉前应用抗胆碱能药物的选择与考虑、抗胆碱能药物的用法用量及注意事项等方面,对术前应用抗胆碱能药物的要点进行阐述。 相似文献
140.
目的 比较40岁以上高龄女性累积胚胎后移植与非累积胚胎进行移植的妊娠结局。方法选择40岁以上且使用自身卵子进行冻融胚胎移植助孕229例不孕症妇女共338个周期资料,根据患者是否累积胚胎移植分为两组分析妊娠结局。 结果40~49岁女性随着年龄增高,基础卵泡刺激素水平升高(P<0.05),获卵数减少(P<0.05),临床妊娠率和持续妊娠率下降(P<0.05)。在40岁妇女中,累积胚胎移植组的临床妊娠率和持续妊娠率均高于非累积胚胎移植组(42.9% vs. 24.6%,P<0.05),对于41岁、42岁、≥43岁,两组的临床妊娠率、持续妊娠率及早期流产率差异均无统计学意义(P>0.05)。结论对于40岁不孕妇女,多次取卵累积胚胎后移植有助于提高临床妊娠率,对41岁以上女性累积胚胎对于助孕结局的益处有限。 相似文献