全文获取类型
收费全文 | 9530篇 |
免费 | 713篇 |
国内免费 | 25篇 |
专业分类
耳鼻咽喉 | 70篇 |
儿科学 | 310篇 |
妇产科学 | 322篇 |
基础医学 | 1220篇 |
口腔科学 | 199篇 |
临床医学 | 1252篇 |
内科学 | 1603篇 |
皮肤病学 | 184篇 |
神经病学 | 862篇 |
特种医学 | 225篇 |
外科学 | 979篇 |
综合类 | 88篇 |
一般理论 | 19篇 |
预防医学 | 1262篇 |
眼科学 | 133篇 |
药学 | 739篇 |
中国医学 | 13篇 |
肿瘤学 | 788篇 |
出版年
2024年 | 23篇 |
2023年 | 120篇 |
2022年 | 129篇 |
2021年 | 245篇 |
2020年 | 204篇 |
2019年 | 258篇 |
2018年 | 282篇 |
2017年 | 231篇 |
2016年 | 284篇 |
2015年 | 282篇 |
2014年 | 336篇 |
2013年 | 508篇 |
2012年 | 724篇 |
2011年 | 789篇 |
2010年 | 394篇 |
2009年 | 332篇 |
2008年 | 611篇 |
2007年 | 594篇 |
2006年 | 598篇 |
2005年 | 554篇 |
2004年 | 420篇 |
2003年 | 456篇 |
2002年 | 387篇 |
2001年 | 110篇 |
2000年 | 89篇 |
1999年 | 87篇 |
1998年 | 79篇 |
1997年 | 63篇 |
1996年 | 55篇 |
1995年 | 46篇 |
1994年 | 55篇 |
1993年 | 45篇 |
1992年 | 73篇 |
1991年 | 48篇 |
1990年 | 59篇 |
1989年 | 60篇 |
1988年 | 58篇 |
1987年 | 43篇 |
1986年 | 56篇 |
1985年 | 32篇 |
1984年 | 36篇 |
1983年 | 30篇 |
1982年 | 28篇 |
1981年 | 24篇 |
1980年 | 19篇 |
1979年 | 31篇 |
1978年 | 22篇 |
1977年 | 21篇 |
1974年 | 28篇 |
1969年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Telleria J Barnabé C Hide M Bañuls AL Tibayrenc M 《Molecular and biochemical parasitology》2004,135(1):133-141
Inositol is an essential precursor for the formation of glycosyl-phosphatidylinositol (GPI)-anchors found in the majority of surface molecules in trypanosomatids, in addition to its requirement for phoshatidylinositol signal transduction pathways. In Leishmania donovani, high-affinity inositol transport is catalyzed by the active myo-inositol/H+ transporter MIT, which is driven by a proton gradient across the parasite membrane. We have characterized the substrate specificity and pharmacology of L. donovani MIT in vitro and in promastigote cultures. High substrate specificity of myo-inositol transport was shown in competition studies with 14 different monosaccharides and MIT function was unaffected by the structurally similar pentose sugars or hexoses. L-Fucose and D-xylose, both inhibitors of the Na+-dependent inositol transport system in the human host, did not affect MIT transport function in the parasite. Competition studies with eight different inositol isomers revealed that proton bonds between the C-2, C-3 and C-5 hydroxyl groups of myo-inositol and the transporter protein played a critical role for substrate recognition, and the C-3 hydroxyl oxygen appears to act as an electron donor to form an H-bond with a positive charge of the MIT permease. The cytotoxic inositol analogue 3-fluoro-myo-inositol was recognized by MIT with similar affinity as myo-inositol and showed an IC50 value of 42 +/- 8 microM in L. donovani cultures. Finally, substrate affinities of MIT revealed apparent Km values of 84 +/- 8 microM for myo-inositol and 5.4 +/- 0.9 nM for H+, equal pH 8.27 + 0.08, suggesting that the L. donovani myo-inositol/H+ symporter is fully activated at physiological pH in the sandfly midgut or macrophage phagolysosome. We conclude that Leishmania MIT constitutes an attractive target for delivery of cytotoxic inositol analogues and differs significantly from the sodium-coupled myo-inositol transport system of the human host. 相似文献
52.
Dr. Hans de Vries Jenny C. de Jonge Peter van't Sant Etienne Agsteribbe Annika Arnberg 《Current genetics》1981,3(3):205-211
Summary [E35], an extranuclear mutant of Neurospora crassa has all the phenotypic characteristics of the stopper mutants (De Vries et al. 1980). In the present work, the mitochondrial DNA as well as the mitochondrial translation products are characterized further. The primary mutational event appears to have been the deletion of about 4 kbp from the wild-type genome. Moreover, after prolonged vegetative growth the mutant accumulates an 8-m circular mtDNA, which was demonstrated both by electronmicroscopy and by restriction enzyme analysis. Hence, the mutant contains two populations of aberrant mitochondrial DNA, the smaller of which is an amplification of the rRNA-tRNA part of the larger. We propose that the primary deletion has generated a signal in the larger DNA which can cause premature termination of replication at the deletion site, and subsequent circularization of the unfinished daughter molecule. Finally, the deleted part may contain a determinant for synthesis of a protein of 11 kDal. The function of this protein, which is not a subunit of the F0 ATPase, is not yet known.Abbreviations (k)bp
(kilo)basepairs
- kDal
kilodalton
- mt
mitochondrial 相似文献
53.
54.
Mauricio Anne M. Rudo-Stern Jenna Dishion Thomas J. Shaw Daniel S. Gill Anne M. Lundgren Julie S. Thunberg Jenny 《Prevention science》2021,22(1):73-83
Prevention Science - This study is a qualitative analysis of facilitators and barriers in the dissemination of Family Check-Up (FCU), a U.S.-developed preventive intervention in Sweden. The FCU is... 相似文献
55.
Carolina Tisnado Garland Line Guénette Edeltraut Kröger Pierre-Hugues Carmichael Rachel Rouleau Caroline Sirois 《Journal of the American Medical Directors Association》2021,22(1):141-147
ObjectivesAssess the impact of a new pharmaceutical care model on (1) polypharmacy and (2) potentially inappropriate medication (PIM) use in long-term care facilities (LTCFs).DesignPragmatic quasi-experimental study with a control group. This multifaceted model enables pharmacists and nurses to increase their professional autonomy by enforcing laws designed to expand their scope of practice. It also involves a strategic reorganization of care, interdisciplinary training, and systematic medication reviews.Setting and ParticipantsTwo LTCFs exposed to the model (409 residents) were compared to 2 control LTCFs (282 residents) in Quebec, Canada. All individuals were aged 65 years or older and residing in included LTCFs.MeasuresPolypharmacy (≥10 medications) and PIM (2015 Beers criteria) were analyzed throughout 12 months between March 2017 and June 2018. Groups were compared before and after implementation using repeated measures mixed Poisson or logistic regression models, adjusting for potential confounding variables.ResultsOver 12 months, for regular medications, polypharmacy decreased from 42% to 20% (exposed group) and from 50% to 41% (control group) [difference in differences (DID): 13%, P < .001]. Mean number of PIMs also decreased from 0.79 to 0.56 (exposed group) and from 1.08 to 0.90 (control group) (DID: 0.05, P = .002).Conclusions and ImplicationsCompared with usual care, this multifaceted model reduced the probability of receiving ≥10 medications and the mean number of PIMs. Greater professional autonomy, reorganization of care, training, and medication review can optimize pharmaceutical care. As the role of pharmacists is expanding in many countries, this model shows what could be achieved with increased professional autonomy of pharmacists and nurses in LTCFs. 相似文献
56.
57.
Dellucci Trey V. Carmichael Cheryl Starks Tyrel J. 《Archives of sexual behavior》2021,50(4):1689-1700
Archives of Sexual Behavior - One- to two-thirds of new HIV infections among sexual minority men occur within the context of main partnerships. This has led to increasing attention to the rules and... 相似文献
58.
X. Artières J. Y. Jenny G. Jenny 《European journal of orthopaedic surgery & traumatology : orthopedie traumatologie》1993,3(2):131-135
Résumé L'étude porte sur une série de 50 prothèses totales de genou GSB implantées entre 1981 et 1988 au Centre de Traumatologie et d'Orthopédie de Strasbourg. Cette prothèse entre dans la catégorie des prothèses à charnières cimentées, mais son pivot semi rigide diminue efficacement les contraintes exercées sur le ciment. Les résultats sont conformes à ceux retrouvés dans la littérature concernant les prothèses à charnière. L'accent a été mis plus particulièrement sur les complications spécifiques à ce type d'arthroplastie : infections, fractures, complications rotuliennes. Cependant le caractère semi rigide de la GSB a permis la disparition presque totale des descellements qui compliquaient d'ordinaire les prothèses à charnière. La prothèse GSB nous semble donc supérieure aux autres modèles de prothèse à charnière. 相似文献
59.
Jenny Englert Lena Witzdam Dominik Söder Manuela Garay-Sarmiento Anton Joseph Anna M. Wagner Cesar Rodriguez-Emmenegger 《Macromolecular chemistry and physics.》2023,224(24):2300306
The immobilization of vesicles has been conceptualized as a method to functionalize biointerfaces. However, the preservation of their integrity post immobilization remains a considerable challenge. Interfacial interactions can cause vesicle rupture upon close surface contact and non-specific protein adsorption impairing surface functions. To date, immobilization of vesicles has relied solely on either entrapment or prior modification of vesicles, both of which require laborious preparation and limit their applications. This work develops a bioinspired strategy to pin vesicles without prior modification while preserving their intact shape. This work introduces antifouling diblock copolymers and ultrathin surface-attached hydrogels containing a brush-like interface consisting of a bottle brush copolymer of N-(2-hydroxypropyl) methacrylamide (HPMA) and N-(3-methacrylamidopropyl)-N,N-dimethyldodecan-1-aminiumiodide (C12+). The presence of positive charges generates an attractive force that pulls vesicles toward the surface. At the surface, the amphiphilic properties of the combs facilitate their insertion into the membrane, mimicking the harpooning mechanism observed in antimicrobial peptides. Importantly, the antifouling poly(HPMA) backdrop serves to safeguard the vesicles by preventing deformation and breakage. Using a combination of thermodynamic analysis, surface plasmon resonance, and confocal laser scanning microscopy, this work demonstrates the efficiency of this biomimetic system to capture vesicles while maintaining an antifouling interface necessary for bioapplications. 相似文献
60.