首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3889篇
  免费   746篇
  国内免费   35篇
耳鼻咽喉   1篇
儿科学   35篇
妇产科学   14篇
基础医学   217篇
口腔科学   8篇
临床医学   232篇
内科学   1001篇
皮肤病学   10篇
神经病学   45篇
特种医学   40篇
外科学   47篇
综合类   310篇
现状与发展   5篇
预防医学   2414篇
眼科学   9篇
药学   134篇
中国医学   17篇
肿瘤学   131篇
  2024年   10篇
  2023年   112篇
  2022年   204篇
  2021年   220篇
  2020年   275篇
  2019年   203篇
  2018年   157篇
  2017年   155篇
  2016年   163篇
  2015年   189篇
  2014年   371篇
  2013年   321篇
  2012年   532篇
  2011年   418篇
  2010年   272篇
  2009年   271篇
  2008年   134篇
  2007年   217篇
  2006年   169篇
  2005年   65篇
  2004年   43篇
  2003年   40篇
  2002年   38篇
  2001年   21篇
  2000年   10篇
  1999年   14篇
  1998年   8篇
  1997年   6篇
  1996年   10篇
  1995年   2篇
  1994年   3篇
  1993年   5篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   1篇
  1988年   5篇
排序方式: 共有4670条查询结果,搜索用时 15 毫秒
81.
《Vaccine》2015,33(25):2917-2921
In 2012–2013, we examined 1729 laboratory-confirmed A(H1N1)pdm09 influenza cases matched 1:1 with healthy controls and estimated influenza vaccine effectiveness (VE) for trivalent inactivated influenza vaccine (IIV3) to be 67% (95% confidence interval = 58–74%) for ages 8 months to 6 years old. Among children aged 8–35 months old, VE for fully vaccinated children (73%, 60–81%) was significantly higher than VE for partially vaccinated children (55%, 33–70%). Significant cross-season protection from prior IIV3 was noted, including VE of 31% (8–48%) from IIV3 received in 2010–2011 against influenza illness in 2012––2013 without subsequent boosting doses.  相似文献   
82.
Background and aimsSome amino acids (AAs) may be associated with type 2 diabetes (T2DM). This study aimed to determine the associations of individual AAs with the development of T2DM in rural Chinese adults.Methods and resultsA cohort study of 1199 individuals aged 18 years or older was conducted from 2006 to 2008 in a rural community of Deqing, China, a repeated survey was done in 2015 and data linkage with the electronic health records system was performed each year for identifying new T2DM cases. A high-performance liquid chromatography approach was used to measure the baseline serum concentrations of 15 AAs. Cox proportional hazards models were used to examine the associations between AAs and the risk of incident T2DM. A total of 98 new T2DM cases were identified during the follow-up of 12 years on average. Among 15 AAs, proline was associated with an increased risk of incident T2DM after adjusted for age, sex, body mass index, fasting plasma glucose, family history of T2DM, smoking status, alcohol use, and history of hypertension, the adjusted hazard ratio for 1-standard deviation increment was 1.20 (95% confidence interval: 1.00, 1.43). The association tended to be more marked in subjects younger than 60 years and overweight/obese subjects. Among participants without hypertension, proline and phenylalanine were associated with an increased risk of incident T2DM, while aspartic acid was associated with a decreased risk.ConclusionSerum proline was associated with the risk of incident T2DM in rural Chinese adults and might be a potential predictor.  相似文献   
83.
84.
Alcohol consumption is customary in many cultures and it is a common human behavior worldwide. Binge ethanol and chronic alcohol consumption, two usual drinking patterns of human beings, produce a state of oxidative stress in liver and disturb the liver function. However, a safe and effective therapy for alcoholic liver disease in humans is still elusive. This study identified the natural product berberine as a potential agent for treating or preventing ethanol-induced liver injury. We demonstrated that berberine attenuated oxidative stress resulted from binge drinking in liver by reducing hepatic lipid peroxidation, glutathione exhaust and mitochondrial oxidative damage. Furthermore, berberine also prevented the oxidative stress and macrosteatosis in response to chronic ethanol exposure in mice. Either the total cytochrome P450 2E1 or the mitochondria-located cytochrome P450 2E1, which is implicated in ethanol-mediated oxidative stress, was suppressed by berberine. On the other hand, berberine significantly blunted the lipid accumulation in liver due to chronic alcohol consumption, at least partially, through restoring peroxisome proliferator-activated receptor α/peroxisome proliferator-activated receptor-gamma Co-activator-1α and hepatocyte nuclear factor 4α/microsomal triglyceride transfer protein pathways. These findings suggested that berberine could serve as a potential agent for preventing or treating human alcoholic liver disease.  相似文献   
85.
86.
87.
目的 了解福寿螺处于休眠期对其体内感染的广州管圆线虫幼虫生长发育及其感染性的影响。 方法 来自实验室的广州管圆线虫L1幼虫感染福寿螺,感染后第1 天螺置于25.0~25.5 ℃ 恒温室中休眠,观察体内幼虫生长发育情况,第13天起解剖观察幼虫生长发育情况。感染后第20 天福寿螺置冬季室内自然变温条件下休眠2个月,每隔10 d观察螺体内幼虫活力。检获的L3幼虫经口或腹腔注射感染SD大鼠,观察其感染性。同时观察螺的生存与体重变化情况,并以水族缸饲养螺作平行对照。 结果 25.0~25.5 ℃ 恒温条件下螺休眠不影响体内幼虫发育,且其幼虫发育历期为(16.3±0.6) d,显著快于水族缸饲养螺(17.6±0.96)d(t=5.72,P<0.01)。冬季室内自然变温条件下的休眠螺,生存率高于水族缸饲养螺(P<0.05),体重下降率为(33.5±4.3)%, 也高于水族缸饲养螺[(9.0±2.3)%, t=10.68, P<0.01]。但随着休眠期的延长其死亡率增高(x2=18.31,P<0.01)。从存活螺体内检获的不同活力的L3幼虫均可感染SD大鼠。 结论 25.0~25.5 ℃ 恒温条件下螺休眠不影响体内幼虫发育,冬季室内自然变温条件下螺休眠或水族缸饲养,其体内幼虫均具有感染性。 感染的福寿螺越冬方式,休眠明显优于水族缸饲养。  相似文献   
88.
AimTo investigate the association between mean fasting glucose (FG) and variability in visit-to-visit FG and risk of mortality in people with type 2 diabetes (T2D).MethodsThis retrospective cohort study included 48,077 Chinese men and women with T2D. The yearly mean and coefficient of variation for fasting glucose (mean-FG and FG-CV, respectively) were based on at least two measurements taken each year over a mean duration of 4.5 years. Deaths and their causes were identified using the Shanghai Vital Statistics registry. Mean-FG and FG-CV served as time-dependent variables in Cox models to estimate their associations with risk of mortality; hazard ratios (HRs) were adjusted for baseline risk factors. Potential non-linear associations were examined by restricted cubic splines.ResultsDuring an average 4.5 years of follow-up, 2095 men and 1923 women died. Men with low mean-FG and women with low or high FG were at greater risk of death. Mean-FG was not associated with either cardiovascular disease (CVD) or cancer-specific mortality, whereas higher yearly FG-CV was associated with all-cause and CVD-/cancer-specific mortality in both genders. Compared with a yearly FG-CV of 1.76 (5th percentile), men and women with an FG-CV of 14.14 (75th percentile) had HRs (95% CI) of 1.41 (1.24–1.61) and 1.44 (1.26–1.65), respectively, for all-cause mortality.ConclusionVariability of visit-to-visit FG may be a more sensitive predictor of risk of death than mean-FG in people with T2D.  相似文献   
89.
《Vaccine》2015,33(30):3504-3511
Hepatitis E virus (HEV) is a serious public health problem that causes acute hepatitis in humans and is primarily transmitted through fecal and oral routes. The major anti-HEV antibody responses are against conformational epitopes located in a.a. 459–606 of HEV pORF2. All reported neutralization epitopes are present on the dimer domain constructed by this peptide. While looking for a neutralizing monoclonal antibody (MAb)-recognized linear epitope, we found a novel neutralizing linear epitope (L2) located in a.a. 423–437 of pORF2. Moreover, epitope L2 is proved non-immunodominant in the HEV-infection process. Using the hepatitis B virus core protein (HBc) as a carrier to display this novel linear epitope, we show herein that this epitope could induce a neutralizing antibody response against HEV in mice and could protect rhesus monkeys from HEV infection. Collectively, our results showed a novel non-immunodominant linear neutralizing epitope of hepatitis E virus, which provided additional insight of HEV vaccine.  相似文献   
90.
《Vaccine》2015,33(20):2335-2341
Enterovirus 71 (EV71) is one of the major causative pathogens of hand, foot and mouth disease (HFMD), which is highly prevalent in the Asia-Pacific regions. Severe HFMD cases with neurological complications and even death are often associated with EV71 infections. However, no licensed EV71 vaccine is currently available. Recombinant virus-like particles (VLPs) of EV71 have been produced and shown to be a promising vaccine candidate in preclinical studies. However, the performance of current recombinant expression systems for EV71 VLP production remains unsatisfactory with regard to VLP yield and manufacturing procedure, and thus hinders further product development. In this study, we evaluated the expression of EV71 VLPs in Pichia pastoris and determined their protective efficacy in mouse models of EV71 infections. We showed that EV71 VLPs could be produced at high levels up to 4.9% of total soluble protein in transgenic P. pastoris yeast co-expressing P1 and 3CD proteins of EV71. The resulting yeast-produced VLPs potently induced neutralizing antibodies against homologous and heterologous EV71 strains in mice. More importantly, maternal immunization with VLPs protected neonatal mice in both intraperitoneal and oral challenge experiments. Collectively, these results demonstrated the success of simple, high-yield production of EV71 VLPs in transgenic P. pastoris, thus lifting the major roadblock in commercial development of VLP-based EV71 vaccines.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号