全文获取类型
收费全文 | 5396篇 |
免费 | 309篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 24篇 |
儿科学 | 192篇 |
妇产科学 | 91篇 |
基础医学 | 791篇 |
口腔科学 | 54篇 |
临床医学 | 604篇 |
内科学 | 1199篇 |
皮肤病学 | 93篇 |
神经病学 | 539篇 |
特种医学 | 123篇 |
外科学 | 605篇 |
综合类 | 54篇 |
一般理论 | 1篇 |
预防医学 | 561篇 |
眼科学 | 80篇 |
药学 | 408篇 |
中国医学 | 15篇 |
肿瘤学 | 289篇 |
出版年
2024年 | 29篇 |
2023年 | 86篇 |
2022年 | 117篇 |
2021年 | 233篇 |
2020年 | 148篇 |
2019年 | 208篇 |
2018年 | 201篇 |
2017年 | 148篇 |
2016年 | 175篇 |
2015年 | 189篇 |
2014年 | 216篇 |
2013年 | 282篇 |
2012年 | 418篇 |
2011年 | 447篇 |
2010年 | 232篇 |
2009年 | 193篇 |
2008年 | 360篇 |
2007年 | 316篇 |
2006年 | 365篇 |
2005年 | 321篇 |
2004年 | 291篇 |
2003年 | 265篇 |
2002年 | 186篇 |
2001年 | 27篇 |
2000年 | 15篇 |
1999年 | 33篇 |
1998年 | 40篇 |
1997年 | 30篇 |
1996年 | 21篇 |
1995年 | 29篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 10篇 |
1991年 | 10篇 |
1990年 | 8篇 |
1989年 | 11篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1969年 | 1篇 |
1967年 | 2篇 |
1935年 | 1篇 |
1934年 | 1篇 |
1930年 | 1篇 |
1924年 | 1篇 |
1906年 | 1篇 |
排序方式: 共有5723条查询结果,搜索用时 15 毫秒
51.
52.
Oleg A. Ivashkevich Pavel. N. Gaponik Tamara B. Kovalyova Nonna I. Makarevich Natalia I. Sushko 《Macromolecular chemistry and physics.》1992,193(6):1369-1376
Three novel monomers: 2-ethyl-, 2-isopropyl- and 2-tert-butyl-5-vinyltetrazole were synthesized. The copolymerizations of these monomers and 2-methyl-5-vinyltetrazole with styrene and methyl methacrylate were examined and the corresponding reactivity ratios r1, r2 and the Alfrey-Price Q, e values estimated. The obtained results, together with IR, 1H NMR and 13C NMR data and quantum-chemical calculations of vinyltetrazole molecules by the AM-1 method, indicate that the type and the size of the substituent does not essentially influence the reactivity of 2-alkyl-5-vinyltetrazoles in radical copolymerization with vinyl monomers. 相似文献
53.
Meredith A. Dilley Mallikarjuna Rettiganti Lynn Christie Erin OBrien Megan Patterson Connelly Weeks Julia Aronson Amy M. Scurlock Tamara T. Perry Robbie D. Pesek Matthew C. Bell Joshua L. Kennedy Peggy Chandler James Magee Larry Simmons Sheva K. Chervinskiy Patrick Casey Stacie M. Jones 《Pediatric allergy and immunology》2019,30(3):363-369
54.
Tamara T. Bradford Joshua A. Daily Sean M. Lang Jeffrey M. Gossett Xinyu Tang R. Thomas Collins 《Pediatric transplantation》2019,23(6)
Data investigating the impact of household income and other factors on SV patient status‐post‐Fontan palliation after heart transplantation are lacking. We aim to evaluate factors affecting outcomes after OHT in this population. The PHIS database was interrogated for either SV or myocarditis/primary CM who were 4 years or older who underwent a single OHT. There were 1599 patients with a median age of 13.2 years (IQR: 9.3‐16.1). Total hospital costs were significantly higher in the SV group ($408 000 vs $294 000, P < 0.0001), but as median household income increased, the risk of inhospital mortality, post‐transplant LOS, and LOS‐adjusted total hospital costs all decreased. The risk of inhospital mortality increased 6.5% per 1 year of age increase at the time of transplant. Patients in the SV group had significantly more diagnoses than those in the CM group (21 vs 15, P < 0.0001) and had longer total hospital LOSs as a result of longer post‐transplant courses (25 days vs 15, P < 0.0001). Increased median household income and younger age are associated with decreased resource utilization and improved inhospital mortality in SV CHD patients who undergo OHT. In conclusion, earlier consideration of OHT in this population, coupled with improved selection criteria, may increase survival in this population. 相似文献
55.
56.
Risk for alcohol dependence in humans has substantial genetic contributions. Successful rodent models generally attempt to
address only selected features of the human diagnosis. Most such models target the phenotype of oral administration of alcohol
solutions, usually consumption of or preference for an alcohol solution versus water. Data from rats and mice for more than
50 years have shown genetic influences on preference drinking and related phenotypes. This paper summarizes some key findings
from that extensive literature. Much has been learned, including the genomic location and possible identity of several genes
influencing preference drinking. We report new information from congenic lines confirming QTLs for drinking on mouse chromosomes
2 and 9. There are many strengths of the various phenotypic assays used to study drinking, but there are also some weaknesses.
One major weakness, the lack of drinking excessively enough to become intoxicated, has recently been addressed with a new
genetic animal model, mouse lines selectively bred for their high and intoxicating blood alcohol levels after a limited period
of drinking in the circadian dark. We report here results from a second replicate of that selection and compare them with
the first replicate. 相似文献
57.
58.
Tamara Teros-Jaakkola Laura Toivonen Linnea Schuez-Havupalo Sinikka Karppinen Ilkka Julkunen Matti Waris Ville Peltola 《Journal of microbiology, immunology, and infection》2019,52(4):526-533
Background/purposeInfluenza vaccine has been recommended in Finland since 2007 for all children of 6–35 months of age and in 2009 for those ≥6 months against pandemic influenza. We investigated the incidence of influenza and vaccine effectiveness in a birth cohort of children in 2008–2011.MethodsWe followed 923 children from birth to 2 years of age for respiratory tract infections. A nasal swab sample for PCR for influenza A and B viruses was taken at the onset of acute respiratory infections. Samples were collected either at the study clinic or at home by parents. Vaccination data was retrieved from the health registries.ResultsVaccination coverage of children aged 6–23 months was 22–47% against seasonal influenza and 80% against the A(H1N1)pdm09 virus in the pandemic season 2009–2010. During 3 influenza seasons, 1607 nasal swab samples were collected. Influenza was confirmed in 56 (6.1%) of 923 children (16 A(H1N1), 14 A(H3N2), and 26 B viruses). The incidence of influenza was 5.1% in 2008–2009, 2.7% in 2009–2010, and 5.0% in 2010–2011. Effectiveness of the adjuvanted vaccine against the pandemic influenza A(H1N1)pdm09 was 97% (95% confidence interval, 76–100%). Three children with influenza were hospitalized.ConclusionThe yearly incidence of seasonal influenza was 5% in this cohort of very young children with variable influenza vaccine coverage. Adjuvanted vaccine against the pandemic influenza was highly effective. Both seasonal and pandemic influenza cases were mostly non-severe. 相似文献
59.
60.
Vahur Ööpik Mati Pääsuke Saima Timpmann Luule Medijainen Jaan Ereline Tamara Smirnova 《European journal of applied physiology》1998,78(1):83-92
Well-trained subjects (n=6) were studied before and after losing a mean 3.0%–4.3% of body mass to determine whether muscle performance could be maintained or even enhanced by dietary creatine supplementation. During a 5-day period of loss of mass the subjects were randomly assigned to a creatine or placebo supplemented diet. All the subjects were measured before and after loss of mass on both supplements for isokinetic peak torque (PT) and work at peak torque (W PT) of knee extensors, also for intermittent high intensity working capacity of the same muscle group. The latter test consisted of submaximal isokinetic knee extensions at an angular velocity of 1.57 rad?·?s?1 for 45 s at the rate of 30 contractions each min (submaximal work, W s max ) followed by 15-s maximal effort (maximal work, W max ). Total duration of the test was 3 min. Haematocrit was measured and haemoglobin, ammonia, lactate, glucose and urea concentrations were analysed in blood samples obtained at rest and after cessation of muscle performance tests. The results indicated that creatine supplementation in comparison with placebo treatment during rapid body mass reduction may help to maintain muscle PT and W PT at high angular velocities, not influencing W max and the rate of fatigue development during W max , but affecting adversely W s max . Within the limitations of the present study the reasons for the partially detrimental effect of creatine administration remain obscure, but it is suggested that impaired creatine uptake in muscle during body mass loss as well as creatine induced changes in muscle glucose and glycogen metabolism may be involved. 相似文献