全文获取类型
收费全文 | 3120篇 |
免费 | 232篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 43篇 |
妇产科学 | 75篇 |
基础医学 | 486篇 |
口腔科学 | 49篇 |
临床医学 | 291篇 |
内科学 | 609篇 |
皮肤病学 | 72篇 |
神经病学 | 173篇 |
特种医学 | 154篇 |
外科学 | 564篇 |
综合类 | 38篇 |
一般理论 | 2篇 |
预防医学 | 200篇 |
眼科学 | 86篇 |
药学 | 180篇 |
中国医学 | 2篇 |
肿瘤学 | 298篇 |
出版年
2024年 | 7篇 |
2023年 | 29篇 |
2022年 | 47篇 |
2021年 | 104篇 |
2020年 | 76篇 |
2019年 | 112篇 |
2018年 | 118篇 |
2017年 | 73篇 |
2016年 | 73篇 |
2015年 | 110篇 |
2014年 | 127篇 |
2013年 | 197篇 |
2012年 | 249篇 |
2011年 | 255篇 |
2010年 | 181篇 |
2009年 | 135篇 |
2008年 | 194篇 |
2007年 | 191篇 |
2006年 | 191篇 |
2005年 | 182篇 |
2004年 | 184篇 |
2003年 | 152篇 |
2002年 | 120篇 |
2001年 | 19篇 |
2000年 | 28篇 |
1999年 | 29篇 |
1998年 | 23篇 |
1997年 | 17篇 |
1996年 | 10篇 |
1995年 | 17篇 |
1994年 | 12篇 |
1993年 | 18篇 |
1992年 | 4篇 |
1991年 | 12篇 |
1990年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1964年 | 3篇 |
排序方式: 共有3365条查询结果,搜索用时 15 毫秒
91.
92.
Bing Yu Yan Zheng Jennifer A. Nettleton Danny Alexander Josef Coresh Eric Boerwinkle 《Clinical journal of the American Society of Nephrology》2014,9(8):1410-1417
Background and objectives
Novel biomarkers that more accurately reflect kidney function and predict future CKD are needed. The human metabolome is the product of multiple physiologic or pathophysiologic processes and may provide novel insight into disease etiology and progression. This study investigated whether estimated kidney function would be associated with multiple metabolites and whether selected metabolomic factors would be independent risk factors for incident CKD.Design, setting, participants, & measurements
In total, 1921 African Americans free of CKD with a median of 19.6 years follow-up among the Atherosclerosis Risk in Communities Study were included. A total of 204 serum metabolites quantified by untargeted gas chromatography–mass spectrometry and liquid chromatography–mass spectrometry was analyzed by both linear regression for the cross-sectional associations with eGFR (specified by the Chronic Kidney Disease Epidemiology Collaboration equation) and Cox proportional hazards model for the longitudinal associations with incident CKD.Results
Forty named and 34 unnamed metabolites were found to be associated with eGFR specified by the Chronic Kidney Disease Epidemiology Collaboration equation with creatine and 3-indoxyl sulfate showing the strongest positive (2.8 ml/min per 1.73 m2 per +1 SD; 95% confidence interval, 2.1 to 3.5) and negative association (−14.2 ml/min per 1.73 m2 per +1 SD; 95% confidence interval, −17.0 to −11.3), respectively. Two hundred four incident CKD events with a median follow-up time of 19.6 years were included in the survival analyses. Higher levels of 5-oxoproline (hazard ratio, 0.70; 95% confidence interval, 0.60 to 0.82) and 1,5-anhydroglucitol (hazard ratio, 0.68; 95% confidence interval, 0.58 to 0.80) were significantly related to lower risk of incident CKD, and the associations did not appreciably change when mutually adjusted.Conclusions
These data identify a large number of metabolites associated with kidney function as well as two metabolites that are candidate risk factors for CKD and may provide new insights into CKD biomarker identification. 相似文献93.
Takeshi Nagamatsu Yuki Iwasawa‐Kawai Mayuko Ichikawa Kei Kawana Takahiro Yamashita Yutaka Osuga Tomoyuki Fujii Danny J. Schust 《American journal of reproductive immunology (New York, N.Y. : 1989)》2014,72(2):182-191
Recent progress in lipid research has unveiled new biologic roles for lysophospholipids as mediators of intercellular signaling. Lysophosphatidic acid (LPA) and sphingosine 1‐phosphate (S1P) are representative lysophospholipids. Accumulating evidence suggests that, acting as intercellular mediators, these and other lysophospholipids may play important roles in physiological and pathological situations. This review discusses the possible involvement of LPA and S1P in reproductive processes, with a focus on the regulatory mechanisms of pregnancy maintenance. As LPA promotes prostaglandin synthesis, mediators in the LPA pathway may also play a significant role in implantation and parturition. S1P signaling is thought to be essential in vascular formation within the uteroplacental unit and in fetomaternal immunologic interactions. Derangements in either one of these lysophospholipid signaling pathways could result in pregnancy complications that may include implantation failure, preeclampsia, and preterm labor. 相似文献
94.
95.
Priscilla Mantik Minli Xie Harvey Wong Hank La Ronald W. Steigerwalt Uday Devanaboyina Geoffrey Ganem Danny Shih John A. Flygare Wayne J. Fairbrother Paroma Chakravarty David Russell Gilberto E. Fernandez Ajit S. Narang 《Journal of pharmaceutical sciences》2019,108(6):1934-1943
Solubilization of new chemical entities for toxicity assessment must use excipients that do not negatively impact drug pharmacokinetics and toxicology. In this study, we investigated the tolerability of a model freebase compound, GDC-0152, solubilized by pH adjustment with succinic acid and complexation with hydroxypropyl-β-cyclodextrin (HP-β-CD) to enable intravenous use. Solubility, critical micelle concentration, and association constant with HP-β-CD were determined. Blood compatibility and potential for hemolysis were assessed in vitro. Local tolerability was assessed after intravenous and subcutaneous injections in rats. A pharmacokinetic study was conducted in rats after intravenous bolus administration.GDC-0152 exhibited pH-dependent solubility that was influenced by self-association. The presence of succinic acid increased solubility in a concentration-dependent manner. HP-β-CD alone also increased solubility, but the extent of solubility enhancement was significantly lower than succinic acid alone. Inclusion of HP-β-CD in the solution of GDC-0152 improved blood compatibility, reduced hemolytic potential by ~20-fold in vitro, and increased the maximum tolerated dose to 80 mg/kg. 相似文献
96.
97.
98.
Angin M Kwon DS Streeck H Wen F King M Rezai A Law K Hongo TC Pyo A Piechocka-Trocha A Toth I Pereyra F Ghebremichael M Rodig SJ Milner DA Richter JM Altfeld M Kaufmann DE Walker BD Addo MM 《The Journal of infectious diseases》2012,205(10):1495-1500
Regulatory T cells (Tregs) are potent immune modulators, but their role in human immunodeficiency virus type 1 (HIV-1) pathogenesis remains poorly understood. We performed a detailed analysis of the frequency and function of Tregs in a large cohort of HIV-1-infected individuals and HIV-1 negative controls. While HIV "elite controllers" and uninfected individuals had similar Treg numbers and frequencies, the absolute numbers of Tregs declined in blood and gut-associated lymphoid tissue in patients with chronic progressive HIV-1 infection. Despite quantitative changes in Tregs, HIV-1 infection was not associated with an impairment of ex vivo suppressive function of flow-sorted Tregs in both HIV controllers and untreated chronic progressors. 相似文献
99.
Wills TA Klug JR Silberman Y Baucum AJ Weitlauf C Colbran RJ Delpire E Winder DG 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(5):E278-E287
The bed nucleus of the stria terminalis (BNST) is a critical region for alcohol/drug-induced negative affect and stress-induced reinstatement. NMDA receptor (NMDAR)-dependent plasticity, such as long-term potentiation (LTP), has been postulated to play key roles in alcohol and drug addiction; yet, to date, little is understood regarding the mechanisms underlying LTP of the BNST, or its regulation by ethanol. Acute and chronic exposure to ethanol modulates glutamate transmission via actions on NMDARs. Despite intense investigation, tests of subunit specificity of ethanol actions on NMDARs using pharmacological approaches have produced mixed results. Thus, we use a conditional GluN2B KO mouse line to assess both basal and ethanol-dependent function of this subunit at glutamate synapses in the BNST. Deletion of GluN2B eliminated LTP, as well as actions of ethanol on NMDAR function. Further, we show that chronic ethanol exposure enhances LTP formation in the BNST. Using KO-validated pharmacological approaches with Ro25-6981 and memantine, we provide evidence suggesting that chronic ethanol exposure enhances LTP in the BNST via paradoxical extrasynaptic NMDAR involvement. These findings demonstrate that GluN2B is a key point of regulation for ethanol's actions and suggest a unique role of extrasynaptic GluN2B-containing receptors in facilitating LTP. 相似文献
100.
Waksman R Barbash IM Dvir D Torguson R Ben-Dor I Maluenda G Xue Z Satler LF Suddath WO Kent KM Pichard AD 《The American journal of cardiology》2012,109(9):1288-1294
Data from randomized clinical trials have shown the safety and efficacy of the XIENCE V in selected populations. However, limited data are available comparing the XIENCE V to the first-generation CYPHER sirolimus-eluting stent. This study aimed to assess the long-term safety and clinical efficacy of the XIENCE V everolimus-eluting stent compared to first-generation stents in an unselected patient population. This retrospective analysis included 6,069 patients treated with CYPHER, TAXUS, and XIENCE stents from 2003 to 2009 at our institution. The patients were followed up for ≥1 year after the index procedure. The baseline characteristics were generally comparable among the 3 groups, with the exception of a significantly greater prevalence of diabetes mellitus, systemic hypertension, and a history of angioplasty and coronary bypass surgery among the XIENCE patients. The XIENCE patients also had a twofold greater rate of type C lesions. One-year follow-up data were available for 82% of the patients. The 1-year major adverse cardiovascular events rate was 9.3% for the XIENCE stent versus 9.8% for the CYPHER stent and 11.5% for the TAXUS stent (p = 0.11). Mortality was lower in the XIENCE group than in the CYPHER and TAXUS groups (3.6% vs 4.9% vs 7.2%, respectively, p <0.001), and target lesion revascularization was similar (5.9% vs 5.2% vs 5.6%, respectively; p = 0.34). Stent thrombosis was lower in the XIENCE patients (0.2% vs 1.2% vs 0.7%, p = 0.007). In conclusion, in a contemporary United States clinical practice with an unselected patient population, use of the XIENCE V stent was associated with an improved safety profile and reduction of all-cause mortality and stent thrombosis compared to first-generation drug-eluting stents. The XIENCE V failed to demonstrate superiority for overall major adverse cardiovascular events, Q-wave myocardial infarction, and revascularization rates. 相似文献