全文获取类型
收费全文 | 1352篇 |
免费 | 110篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 13篇 |
儿科学 | 42篇 |
妇产科学 | 18篇 |
基础医学 | 200篇 |
口腔科学 | 38篇 |
临床医学 | 176篇 |
内科学 | 300篇 |
皮肤病学 | 35篇 |
神经病学 | 62篇 |
特种医学 | 40篇 |
外科学 | 118篇 |
综合类 | 12篇 |
预防医学 | 161篇 |
眼科学 | 17篇 |
药学 | 117篇 |
中国医学 | 10篇 |
肿瘤学 | 114篇 |
出版年
2023年 | 23篇 |
2022年 | 76篇 |
2021年 | 109篇 |
2020年 | 50篇 |
2019年 | 69篇 |
2018年 | 53篇 |
2017年 | 28篇 |
2016年 | 29篇 |
2015年 | 45篇 |
2014年 | 60篇 |
2013年 | 66篇 |
2012年 | 97篇 |
2011年 | 83篇 |
2010年 | 57篇 |
2009年 | 55篇 |
2008年 | 88篇 |
2007年 | 89篇 |
2006年 | 72篇 |
2005年 | 64篇 |
2004年 | 54篇 |
2003年 | 40篇 |
2002年 | 27篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 24篇 |
1997年 | 11篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 8篇 |
1993年 | 10篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 9篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1473条查询结果,搜索用时 15 毫秒
1.
It is hypothesized that persons who use drugs (PWUD) in Vietnam who are also HIV-positive may face additional challenges in psychosocial outcomes, and these challenges may extend to their family members. In this study, we examined depressive symptoms, stigma, social support, and caregiver burden of HIV-positive PWUD and their family members, compared to the outcomes of HIV-negative PWUD and their family members. Baseline, 3-month, and 6-month assessment data were gathered from 83 PWUD and 83 family members recruited from four communes in Phú Th? Province, Vietnam. For PWUD, although we observed a general decline in overall stigma over time for both groups, HIV-positive PWUD consistently reported significantly higher overall stigma for all three periods. Depressive symptoms among family members in both groups declined over time; however, family members of HIV-positive PWUD reported higher depressive symptoms across all three periods. In addition, family members of HIV-positive PWUD reported lower levels of tangible support across all three periods. Caregiver burden among family members of HIV-positive PWUD increased significantly over time, whereas the reported burden among family members of HIV-negative PWUD remained relatively unchanged. The findings highlight the need for future interventions for PWUD and family members, with targeted and culturally specific strategies to focus on the importance of addressing additional stigma experienced by PWUD who are HIV-positive. Such challenges may have direct negative impact on their family members' depressive symptoms, tangible support, and caregiver burden. 相似文献
2.
目的探讨三康胶囊对高原人体运动后一氧化氮(NO)及其合酶(NOS)、乳酸(BLA)、血氨(Ammo)的影响.方法选择进驻海拔3 700 m高原1年的10名健康青年,口服三康胶囊15 d,在服药前后分别采用功量自行车进行渐增负荷运动,测定其血清 NO、NOS、BLA及Ammo含量.结果服药后较服药前运动后NO水平[(101.02±6.49) Vs (77.10±8.11)]和NOS活性[(71.40±7.23) Vs (56.29±6.28)]均增高, BLA[(7.58±0.79)Vs (6.13±0.74)]和Ammo[(80.11±9.44)Vs (69.38±8.86)]降低,有非常显著性差异(P<0.01).结论 三康胶囊能增强高原移居者运动后NOS活性,加速乳酸清除,减缓运动疲劳的发生. 相似文献
3.
4.
5.
The relationship between the amount of inhaled steroids delivered from pressurized metered-dose inhalers used with their recommended holding chambers and age of the patients using these devices was studied in an open randomised cross-over filter study. We recruited 1-2-month-old healthy infants (n = 21), 2-3-year-old asthmatics (n = 13), 4-6-year-old asthmatics (n = 15), and 10-15-year-old asthmatics (n = 20). Each child inhaled two puffs, administered by a single investigator, of both budesonide through Nebuchamber and fluticasone propionate through Babyhaler, on two occasions. Moreover, the 4-6-year-old group inhaled via both facemask and mouthpiece. Drug, collected on a filter interposed between holding chamber and patient, was analysed by high performance liquid chromatography. Filter dose, expressed in percent of the nominal dose, was analysed in a mixed effect linear regression model with age group, holding chamber and inhalation interface (facemask or mouthpiece) as fixed effects and subject as random effect. Filter dose from both holding chambers increased significantly with age, from 3% with Babyhaler and 7% with Nebuchamber in the youngest children, to 40-41% with both holding chambers in adolescents. Nebuchamber delivered more drug than Babyhaler (p = 0.002), but variability in drug delivery (about 11%) was similar between holding chambers. Filter dose decreased from 35% to 22% with Babyhaler, and from 42% to 27% with Nebuchamber when using a mouthpiece rather than a facemask (p < 0.0001). Delivery of inhaled steroids used with their recommended holding chambers depends from age and holding chamber, but also from the inhalation interface. Lung deposition and clinical studies comparing inhalation from holding chambers with mouthpiece and facemask are urgently required. 相似文献
6.
Hung Anh Nguyen Herv Cheradame Ernest Marchal 《Macromolecular chemistry and physics.》1992,193(9):2495-2503
The 1,3-dipolar addition of 2-azido-2,4,4-trimethylpentane ( 1 ) to acetylene and ethylene derivatives such as phenylacetylene (2), acrylonitrile, diphenyl fumarate ( 4 ) and N,N′-methylenebis(1,4-phenylene)dimaleimide ( 8 ) leads to the corresponding triazole and triazoline derivatives. This study demonstrates that tertiary azides are able to react with dienophiles, and the application of this reaction for the synthesis of block copolymers was investigated with monoazido-telechelic poly(2-methylpropene) (PMP). It was shown that the azido group is stable under the severe conditions of the polycondensation reaction without decomposition (170°C, 24 h), and the monoadduct PMP- 8 is produced with acceptable yield. 相似文献
7.
Berhooz Rajabalitabar Hung Anh Nguyen Herv Cheradame 《Macromolecular chemistry and physics.》1995,196(11):3597-3604
Polymerizations of 2-methylpropene (MP) initiated by the system 1,4-bis(1-azido-1-methylethyl)benzene (DAMEB)/BCl3 in the presence of DMSO were carried out by “all monomer in” (AMI) technique at ?70°C in CH2Cl2 solution. FT-IR, 1H NMR and SEC analyses of polymers (PMP) showed that the M n versus weight of PMP plot is a straight line without intercept and azide Fn3 and aromatic ring F? functionalities are close to the theoretical values of 2 and 1, respectively. A polymerization of MP initiated by the system α,ω-diazido-PMP/BCl3/DMSO led to a final poly(2-methylpropene) (PMP) with an increase of M n corresponding to the amount of MP introduced and presenting the same functionalities FN3 and F? as the starting PMP. These results indicate that the polymerization system MP/DAMEB/BCl3/DMSO is a “living” one, because in an acceptably large range of molecular weight (M n < 50000) the Mayo plot 1/DP versus 1/DP 0 is a straight line. The intercept gives ktrM/kp = 4 · 10?5, showing the transfer reaction proceeds at very low rate. 相似文献
8.
Phan TG Nishimura S Okame M Nguyen TA Khamrin P Okitsu S Maneekarn N Ushijima H 《Journal of medical virology》2004,74(1):173-179
A total of 236 fecal specimens collected from infants and children with gastroenteritis in Maizuru city, Japan from July 2002 to June 2003, were tested for the presence of rotaviruses, noroviruses, sapoviruses, astroviruses, and adenoviruses by RT-PCR, PAGE, RPHA, and latex agglutination methods. Among diarrheal viruses detected, group A rotavirus was the most prevalent (32.2%; 76 of 236) followed by norovirus GII (21.2%; 50 of 236), group C rotavirus (10.2%; 24 of 236), adenovirus (3.8%; 9 of 236), sapovirus (2.5%; 6 of 236), astrovirus (1.3%; 3 of 236), and norovirus GI (0.8%; 2 of 236), respectively. It is noteworthy that group C rotavirus infection was apparently confined only within the period of 5 months (December 2002 through April 2003). This pattern of infection implied that the outbreak of group C rotavirus in these patients, which was the first outbreak of gastroenteritis attributed to group C rotavirus in Maizuru city. Moreover, about half (12 of 24) of group C rotavirus infected cases were confined to infants and young children less than 3 years old. Another interesting feature of the study was the demonstration of the mixed infections with group C rotavirus and group A rotavirus, as well as group C rotavirus and norovirus GII in 20.8% (5 of 24) and 8.3% (2 of 24), respectively. This is the first report of gastroenteritis associated with the mixed infections with group C rotavirus and other viral enteropathogens such as norovirus. The results indicate that group C rotavirus could infect not only older children and adults but also infants and young children under 3 years old. 相似文献
9.
The aim of the present study was to examine whether ischaemic episodes of less than 5 min could induce preconditioning or stunning in the isolated rat heart. Hearts were subjected to total global ischaemia of 1, 2 and 4 min followed by 10 min of reperfusion before an 18-min main ischaemic period and 30 min of reperfusion. The effects on physiology, purine metabolism and anaerobic glycolysis were compared with a control group subjected to the main ischaemia only. The brief ischaemic episodes did not produce stunning based on the recovery of left ventricular developed pressure (LVDP) and heart rate (HR) product during the first reperfusion. Preconditioning of 11–14% increased recovery of LVDP x HR during the second reperfusion was observed in the 1- and 4-min group. In the 2-min group a low repayment of flow debt during the first reperfusion was associated with a slightly reduced recovery of LVDP x HR compared to the other preconditioned groups during the second reperfusion. Only in the 4-min group was preconditioning associated with fewer breakdown products of the purine nucleotide pool (adenosine) and anaerobic glycolysis (lactate) in both tissue and effluate after the main ischaemia. Preconditioning (reflected in recovery of function) could be produced with ischaemic episodes of less than 5 min that did not produce stunning. Thus, stunning is probably not the primary cause of preconditioning. 相似文献
10.