全文获取类型
收费全文 | 36986篇 |
免费 | 3064篇 |
国内免费 | 187篇 |
专业分类
耳鼻咽喉 | 411篇 |
儿科学 | 1251篇 |
妇产科学 | 846篇 |
基础医学 | 4383篇 |
口腔科学 | 702篇 |
临床医学 | 3630篇 |
内科学 | 7760篇 |
皮肤病学 | 617篇 |
神经病学 | 2999篇 |
特种医学 | 1128篇 |
外科学 | 5459篇 |
综合类 | 838篇 |
一般理论 | 28篇 |
预防医学 | 2735篇 |
眼科学 | 1456篇 |
药学 | 2811篇 |
1篇 | |
中国医学 | 135篇 |
肿瘤学 | 3047篇 |
出版年
2023年 | 258篇 |
2022年 | 378篇 |
2021年 | 1027篇 |
2020年 | 622篇 |
2019年 | 921篇 |
2018年 | 1029篇 |
2017年 | 754篇 |
2016年 | 856篇 |
2015年 | 981篇 |
2014年 | 1322篇 |
2013年 | 1644篇 |
2012年 | 2579篇 |
2011年 | 2594篇 |
2010年 | 1437篇 |
2009年 | 1279篇 |
2008年 | 2205篇 |
2007年 | 2148篇 |
2006年 | 1978篇 |
2005年 | 1908篇 |
2004年 | 1822篇 |
2003年 | 1565篇 |
2002年 | 1419篇 |
2001年 | 1156篇 |
2000年 | 1038篇 |
1999年 | 891篇 |
1998年 | 340篇 |
1997年 | 251篇 |
1996年 | 226篇 |
1995年 | 225篇 |
1994年 | 199篇 |
1993年 | 185篇 |
1992年 | 529篇 |
1991年 | 487篇 |
1990年 | 447篇 |
1989年 | 409篇 |
1988年 | 369篇 |
1987年 | 341篇 |
1986年 | 335篇 |
1985年 | 331篇 |
1984年 | 229篇 |
1983年 | 207篇 |
1982年 | 142篇 |
1981年 | 105篇 |
1980年 | 112篇 |
1979年 | 161篇 |
1978年 | 95篇 |
1977年 | 103篇 |
1976年 | 71篇 |
1974年 | 85篇 |
1973年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
991.
992.
Rajit K. Basu Yu Wang Hector R. Wong Lakhmir S. Chawla Derek S. Wheeler Stuart L. Goldstein 《Clinical journal of the American Society of Nephrology》2014,9(4):654-662
Background and objectives
Novel AKI biomarkers carry variable performance for prediction of AKI in patients with heterogeneous illness. Until utility is demonstrated in critically ill patients outside of the cardiopulmonary bypass population, AKI biomarkers are unlikely to gain widespread implementation. Operationalization of an AKI risk stratification methodology, termed renal angina, was recently reported to enhance prediction at the time of intensive care unit admission for persistent severe AKI. The renal angina index (RAI) was developed to provide the clinical context to direct AKI biomarker testing. This study tested the hypothesis that incorporation of AKI biomarkers in patients fulfilling renal angina improves the prediction of persistent severe AKI.Design, setting, participants, & measurements
In a multicenter study of 214 patients admitted to the pediatric intensive care unit with sepsis, the discrimination of plasma neutrophil gelatinase–associated lipocalin (NGAL), matrix metalloproteinase-8 (MMP-8), and neutrophil elastase-2 (Ela-2) were determined individually and in combination with the RAI for severe AKI. Net reclassification improvement (NRI) and integrated discrimination improvement (IDI) were calculated.Results
Individual biomarkers demonstrated marginal discrimination for severe AKI (area under curve [AUC]: NGAL, 0.72; MMP-8, 0.68; Ela-2, 0.72), inferior to prediction by the clinical model of the RAI (AUC=0.80). Incorporation of each biomarker significantly added to the renal angina model AKI prediction (AUC=0.80, increased to 0.84–0.88; P<0.05 for each). The inclusion of each biomarker with the RAI demonstrated NRI (0.512, 0.428, and 0.545 for NGAL, MMP-8, and Ela-2, respectively; all P<0.03) and IDI (0.075 for Ela-2). The inclusion of both Ela-2 and NGAL with RAI demonstrated an NRI of 0.871 (P<0.001) and an IDI of 0.1 (P=0.01).Conclusions
This study shows that incorporation of AKI biomarkers into the RAI improves discrimination for severe AKI. The RAI optimizes the utility of AKI biomarkers in a heterogeneous, critically ill patient population. 相似文献993.
994.
Rayaz A Malik Aimee Andag‐Silva Charungthai Dejthevaporn Manfaluthy Hakim Jasmine S Koh Rizaldy Pinzon Norlela Sukor Ka Sing Wong 《Journal of diabetes investigation.》2020,11(5):1097-1103
Burning and stabbing pain in the feet and lower limbs can have a significant impact on the activities of daily living, including walking, climbing stairs and sleeping. Peripheral neuropathy in particular is often misdiagnosed or underdiagnosed because of a lack of awareness amongst both patients and physicians. Furthermore, crude screening tools, such as the 10‐g monofilament, only detect advanced neuropathy and a normal test will lead to false reassurance of those with small fiber mediated painful neuropathy. The underestimation of peripheral neuropathy is highly prevalent in the South‐East Asia region due to a lack of consensus guidance on routine screening and diagnostic pathways. Although neuropathy as a result of diabetes is the most common cause in the region, other causes due to infections (human immunodeficiency virus, hepatitis B or C virus), chronic inflammatory demyelinating polyneuropathy, drug‐induced neuropathy (cancer chemotherapy, antiretrovirals and antituberculous drugs) and vitamin deficiencies (vitamin B1, B6, B12, D) should be actively excluded. 相似文献
995.
Eric Y. Wong Cally A. Jennings Wendy M. Rodgers Anne-Marie Selzler Lindsay G. Simmonds Rashida Hamir Michael K. Stickland 《Patient education and counseling》2014
Objective
This study examined if ongoing support delivered by telephone following pulmonary rehabilitation (PR) assisted chronic obstructive pulmonary disease (COPD) patients to maintain health outcomes.Methods
Phase one (n = 79) compared post-rehabilitation telephone-based support delivered by peers compared to usual care (UC). The second phase (n = 168) compared post-rehabilitation support from peer educators, respiratory therapists (RT), or UC. Primary outcome variables were St. George's Respiratory Questionnaire (SGRQ) total score and the six minute walk test (6MWT). Measures were obtained at baseline, immediately following PR, and six-months post PR.Results
Six-month follow-up data for phase one was collected for 66 COPD patients (n = 35 peer support, n = 31 UC) and 142 for phase two (n = 42 peer support, n = 52 RT support, n = 48 UC). Per-protocol and intention to treat (ITT) analysis in both phases found no significant group by time differences for SGRQ or 6MWT.Conclusion
Providing peer or RT support via telephone following PR was not more effective than UC for maintaining health outcomes.Practice implications
There are concerns with using peers to provide ongoing support to COPD patients. Additionally, COPD patients require a higher level of care than telephone support can provide. 相似文献996.
D. Wong Y. Keynan E. Rubinstein 《European journal of clinical microbiology & infectious diseases》2014,33(11):2053-2059
Echocardiography is an important diagnostic tool in evaluating a patient with Staphylococcus aureus bacteremia (SAB) for diagnosing infective endocarditis (IE). We sought to compare the utility of transthoracic echocardiography (TTE) with transesophageal echocardiography (TEE) in screening for IE in patients with SAB. We performed a retrospective chart review of 285 adult patients from two tertiary care hospitals with at least one positive blood culture for S. aureus between 2010 and 2012. Patients who underwent echocardiography were divided into two groups: TTE (screened with TTE only) and TEE (screened with both TTE and TEE). The demographic factors and clinical outcomes were compared between the groups. Of the 285 charts reviewed, 213 (74.7 %) patients were screened with echocardiography: 183 (85.9 %) were screened with TTE alone and 30 (14.1 %) were screened with both TTE and TEE. TEE disclosed more cases of definite IE than TTE (8 [26.7 %] vs. 22 [12.0 %], p?=?0.046). The TEE group had higher mortality than the TTE group (15 [50.0 %] vs. 43 [23.5 %], p?=?0.004). In patients with definite IE, mortality was higher in the TEE group than in the TTE group (6 [75.0 %] vs. 6 [27.3 %], p?=?0.034). TEE discovered additional findings that were missed by TTE in 36.7 % of cases and refuted the findings of TTE in 13.3 % of cases. We do not support the routine use of TEE in patients with uncomplicated SAB. High-risk patients in which IE is a serious consideration should undergo investigation with TEE. 相似文献
997.
Lin Zhang Joseph JY Sung Jun Yu Siew C Ng Sunny H Wong Chi H Cho Simon SM Ng Francis KL Chan William KK Wu 《The Journal of pathology》2014,233(2):103-112
Helicobacter pylori and Epstein–Barr virus (EBV) account for roughly 80% and 10%, respectively, of gastric carcinomas worldwide. Autophagy is an evolutionarily conserved and intricately regulated cellular process that involves the sequestration of cytoplasmic proteins and organelles into double‐membrane autophagosomes that eventually fuse with lysosomes for degradation of the engulfed content. Emerging evidence indicates that xenophagy, a form of selective autophagy, plays a crucial role in the pathogenesis of H. pylori‐ and EBV‐induced gastric cancer. Xenophagy specifically recognizes intracellular H. pylori and EBV and physically targets these pathogens to the autophagosomal–lysosomal pathway for degradation. In this connection, H. pylori or EBV‐induced dysregulation of autophagy may be causally linked to gastric tumourigenesis and therefore can be exploited as therapeutic targets. This review will discuss how H. pylori and EBV infection activate autophagy and how these pathogens evade recognition and degradation by the autophagic pathway. Elucidating the molecular aspects of H. pylori‐ and EBV‐induced autophagy will help us better understand the pathogenesis of gastric cancer and promote the development of autophagy modulators as antimicrobial agents. Published by John Wiley & Sons, Ltd 相似文献
998.
999.
Tarek El-Bialy Adel Alhadlaq Bryan Wong Cezary Kucharski 《Annals of biomedical engineering》2014,42(7):1406-1412
Dental pulp loss due to caries or pulpitis can affect the longevity of teeth. Dental pulp tissue engineering necessitates the use of progenitor cells that has the potential to differentiate into neural, vascular and odontoblasts like cells. Previous reports have shown that human gingival progenitor cells (HGPCs) can be differentiated into different cell types; however neural differentiation of these cells, to the best of our knowledge, has not been reported. Low intensity pulsed ultrasound (LIPUS) has been reported to enhance cell differentiation. The aims of this study were (1) to explore the potential neural differentiation of HGPCs and (2) to investigate the effect of LIPUS on the differentiation of HGPCs when incubated under neuroinductive conditions. The HGPCs were isolated from human interdental papilla proximal to the premolar teeth that were extracted for orthodontic purpose. The HGPCs were induced to differentiate into neural lineage using a neuroinductive culture medium. HGPCs were divided into four groups; control group, neuro-induction (NI) group, ultrasound group (LIPUS), and a combined NI+LIPUS group. HGPCs were harvested for immunostaining and q-PCR after 1 day. Immunostaining for neuron specific antigens and q-PCR suggested that HGPCs can be differentiated into neural lineage and that selected neurodifferentiation markers can be enhanced by LIPUS. 相似文献
1000.
Samuel D. Banister Richard C. Kevin Lewis Martin Axel Adams Christa Macdonald Jamie J. Manning Rochelle Boyd Michael Cunningham Marc Y. Stevens Iain S. McGregor Michelle Glass Mark Connor Roy R. Gerona 《Drug testing and analysis》2019,11(7):976-989
5F‐PY‐PICA and 5F‐PY‐PINACA are pyrrolidinyl 1‐(5‐fluoropentyl)ind (az)ole‐3‐carboxamides identified in 2015 as putative synthetic cannabinoid receptor agonist (SCRA) new psychoactive substances (NPS). 5F‐PY‐PICA, 5F‐PY‐PINACA, and analogs featuring variation of the 1‐alkyl substituent or contraction, expansion, or scission of the pyrrolidine ring were synthesized and characterized by nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography–quadrupole time‐of‐flight–mass spectrometry (LC–QTOF–MS). In competitive binding experiments against HEK293 cells expressing human cannabinoid receptor type 1 (hCB1) or type 2 (hCB2), all analogs showed minimal affinity for CB1 (pKi < 5), although several demonstrated moderate CB2 binding (pKi 5.45–6.99). In fluorescence‐based membrane potential assays using AtT20‐hCB1 or ‐hCB2 cells, none of the compounds (at 10 μM) produced an effect >50% of the classical cannabinoid agonist CP55,940 (at 1 μM) at hCB1, although several showed slightly higher relative efficacy at hCB2. Expansion of the pyrrolidine ring of 5F‐PY‐PICA to an azepane ( 8 ) conferred the greatest hCB2 affinity (pKi 6.99) and activity (pEC50 7.54, Emax 72%) within the series. Unlike other SCRA NPS evaluated in vivo using radio biotelemetry, 5F‐PY‐PICA and 5F‐PY‐PINACA did not produce cannabimimetic effects (hypothermia, bradycardia) in mice at doses up to 10 mg/kg. 相似文献