全文获取类型
收费全文 | 32273篇 |
免费 | 2728篇 |
国内免费 | 703篇 |
专业分类
耳鼻咽喉 | 71篇 |
儿科学 | 575篇 |
妇产科学 | 240篇 |
基础医学 | 2236篇 |
口腔科学 | 190篇 |
临床医学 | 6592篇 |
内科学 | 10977篇 |
皮肤病学 | 159篇 |
神经病学 | 739篇 |
特种医学 | 1295篇 |
外国民族医学 | 2篇 |
外科学 | 4152篇 |
综合类 | 3574篇 |
一般理论 | 1篇 |
预防医学 | 1204篇 |
眼科学 | 45篇 |
药学 | 2398篇 |
23篇 | |
中国医学 | 689篇 |
肿瘤学 | 542篇 |
出版年
2024年 | 15篇 |
2023年 | 671篇 |
2022年 | 721篇 |
2021年 | 1273篇 |
2020年 | 1544篇 |
2019年 | 1492篇 |
2018年 | 1371篇 |
2017年 | 1117篇 |
2016年 | 947篇 |
2015年 | 1165篇 |
2014年 | 2115篇 |
2013年 | 2322篇 |
2012年 | 1492篇 |
2011年 | 1670篇 |
2010年 | 1316篇 |
2009年 | 1335篇 |
2008年 | 1355篇 |
2007年 | 1360篇 |
2006年 | 1269篇 |
2005年 | 1187篇 |
2004年 | 958篇 |
2003年 | 892篇 |
2002年 | 720篇 |
2001年 | 703篇 |
2000年 | 530篇 |
1999年 | 591篇 |
1998年 | 510篇 |
1997年 | 484篇 |
1996年 | 390篇 |
1995年 | 420篇 |
1994年 | 403篇 |
1993年 | 326篇 |
1992年 | 350篇 |
1991年 | 313篇 |
1990年 | 300篇 |
1989年 | 221篇 |
1988年 | 235篇 |
1987年 | 203篇 |
1986年 | 212篇 |
1985年 | 233篇 |
1984年 | 209篇 |
1983年 | 168篇 |
1982年 | 111篇 |
1981年 | 131篇 |
1980年 | 93篇 |
1979年 | 68篇 |
1978年 | 54篇 |
1977年 | 47篇 |
1976年 | 33篇 |
1975年 | 19篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
A molecular perspective for the use of type IV tyrosine kinase inhibitors as anticancer therapeutics
《Drug discovery today》2022,27(3):808-821
Tyrosine kinases are enzymes that can transfer a phosphate group from ATP to a specific protein tyrosine, serine or threonine residue within a cell, operating as a switch that can turn ‘on’ and ‘off’ causing different physiological alterations in the body. Mutated kinases have been shown to display an equilibrium shift toward the activated state. Types I–III have been studied intensively leading to drugs like imatinib (type II), cobimetinib (type III), among others. It is the same scenario for types V–VII; however, there is a lacuna in information regarding type IV inhibitors, although recently some advances have surfaced. This review aims to accumulate the knowledge gained so far about type IV inhibitors. 相似文献
2.
目的研究异牡荆素(ISO)对非小细胞性肺癌(NSCLC)细胞的影响和潜在的机制。方法将A549和H1650细胞分别分为空白组、低剂量实验组(4μmol·L-1 ISO)和高剂量实验组(16μmol·L-1 ISO)。用噻唑蓝法检测NSCLC细胞活性,用肿瘤球形成实验检测NSCLC细胞的细胞球形成率,用Western blot法检测NSCLC细胞凋亡、自我更新、无翅型MMTV整合位点家族/β-连环蛋白(Wnt/β-catenin)信号通路相关蛋白的表达水平。结果与空白组比较,低、高剂量实验组中A549和H1650细胞在24,48和72 h的细胞活性均显著降低。低、高剂量实验组和空白组中A549细胞的细胞球形成率分别为(4.18±0.45)%,(2.01±0.67)%和(6.02±0.57)%,切割的半胱氨酸蛋白酶-3相对表达量分别为0.24±0.08,1.25±0.13和0.06±0.07,SRY相关高迁移率族盒蛋白-2相对表达量分别为0.49±0.04,0.25±0.03和1.00±0.09,Kruppel样因子4相对表达量分别为0.68±0.04,0.44±0.03和1.01±0.06,Wnt1相对表达量分别为0.63±0.06,0.28±0.04和1.00±0.06,β-catenin相对表达量分别为0.41±0.05,0.22±0.03和1.01±0.09;与空白组比较,低、高剂量实验组中A549细胞的上述指标的差异均有统计学意义(P<0.05,P<0.01)。上述3组中H1650细胞的上述指标也呈现一致的现象。结论ISO可能通过抑制Wnt/β-catenin信号通路来抑制NSCLC细胞活性和自我更新,并促进其凋亡。 相似文献
3.
Andreas Lundin Martin Annborn Ola Borgquist Joachim Düring Johan Undén Christian Rylander 《Acta anaesthesiologica Scandinavica》2023,67(5):655-662
Patients admitted to intensive care after cardiac arrest are at risk of circulatory shock and early mortality due to cardiovascular failure. The aim of this study was to evaluate the ability of the veno-arterial pCO2 difference (∆pCO2; central venous CO2 – arterial CO2) and lactate to predict early mortality in postcardiac arrest patients. This was a pre-planned prospective observational sub-study of the target temperature management 2 trial. The sub-study patients were included at five Swedish sites. Repeated measurements of ∆pCO2 and lactate were conducted at 4, 8, 12, 16, 24, 48, and 72 h after randomization. We assessed the association between each marker and 96-h mortality and their prognostic value for 96-h mortality. One hundred sixty-three patients were included in the analysis. Mortality at 96 h was 17%. During the initial 24 h, there was no difference in ∆pCO2 levels between 96-h survivors and non-survivors. ∆pCO2 measured at 4 h was associated with an increased risk of death within 96 h (adjusted odds ratio: 1.15; 95% confidence interval [CI]: 1.02–1.29; p = .018). Lactate levels were associated with poor outcome over multiple measurements. The area under the receiving operating curve to predict death within 96 h was 0.59 (95% CI: 0.48–0.74) and 0.82 (95% CI: 0.72–0.92) for ∆pCO2 and lactate, respectively. Our results do not support the use of ∆pCO2 to identify patients with early mortality in the postresuscitation phase. In contrast, non-survivors demonstrated higher lactate levels in the initial phase and lactate identified patients with early mortality with moderate accuracy. 相似文献
4.
5.
6.
Sara Järpestam Louise Martinell Christian Rylander Linus Lilja 《Acta anaesthesiologica Scandinavica》2023,67(9):1249-1255
Background
European guidelines recommend targeted temperature management (TTM) in post-cardiac arrest care. A large multicentre clinical trial, however, showed no difference in mortality and neurological outcome when comparing hypothermia to normothermia with early treatment of fever. The study results were valid given a strict protocol for the assessment of prognosis using defined neurological examinations. With the current range of recommended TTM temperatures, and applicable neurological examinations, procedures may differ between hospitals and the variation of clinical practice in Sweden is not known.Aim
The aim of this study was to investigate current practice in post-resuscitation care after cardiac arrest as to temperature targets and assessment of neurological prognosis in Swedish intensive care units (ICUs).Methods
A structured survey was conducted by telephone or e-mail in all Levels 2 and 3 (= 53) Swedish ICUs during the spring of 2022 with a secondary survey in April 2023.Results
Five units were not providing post-cardiac arrest care and were excluded. The response rate was 43/48 (90%) of the eligible units. Among the responding ICUs, normothermia (36–37.7°C) was applied in all centres (2023). There was a detailed routine for the assessment of neurological prognosis in 38/43 (88%) ICUs. Neurological assessment was applied 72–96 h after return of spontaneous circulation in 32/38 (84%) units. Electroencephalogram and computed tomography and/or magnetic resonance imaging were the most common technical methods available.Conclusion
Swedish ICUs use normothermia including early treatment of fever in post-resuscitation care after cardiac arrest and almost all apply a detailed routine for the assessment of neurological prognosis. However, available methods for prognostic evaluation varies between hospitals. 相似文献7.
《Indian heart journal》2022,74(3):182-186
BackgroundIt has been reported that significant endothelial dysfunction or clinically evident vasospasm can be associated with drug-eluting stents (DESs). However, the impact of DES associated coronary artery spasm (CAS) on long-term clinical outcomes has not been fully elucidated as compared with those of patients with vasospastic angina.MethodsA total of 2797 consecutive patients without significant coronary artery lesion (<70%), who underwent the Acetylcholine (Ach) provocation test, were enrolled between Nov 2004 and Oct 2010. DES-associated spasm was defined as significant CAS in proximal or distal to previously implanted DES site at follow-up angiography with Ach test. Patients were divided into two groups (DES-CAS; n = 108, CAS; n = 1878). For adjustment, propensity score matching (PSM) was done (C-statistics = 0.766, DES-CAS; n = 102, CAS; n = 102). SPSS 20 (Inc., Chicago, Illinois) was used to analyze this data.ResultsBaseline characteristics were worse in the DES-CAS group. After PSM, both baseline characteristics and the Ach test results were balanced except higher incidence of diffuse CAS and ECG change in the DES-CAS group. During Ach test, the incidence of diffuse spasm (93.1% vs. 81.3%, p = 0.012) and ST-T change (10.7% vs. 1.9%, p = 0.010) were higher in the DES-CAS group. At 3-year, before and after adjustment, the DES-CAS group showed a higher incidence of coronary revascularization (9.8% vs. 0.0%, p = 0.001), recurrent chest pain requiring follow up coronary angiography (CAG, 24.5% vs. 7.8%, p = 0.001) and major adverse cardiac events (MACEs, 9.8% vs. 0.9%, p < 0.005).ConclusionIn this study, DES associated CAS was associated with higher incidence of diffuse spasm, ST-T change and adverse 3-year clinical outcomes. Special caution should be exercised in this particular subset of patients. 相似文献
8.
《Journal of Cardiovascular Computed Tomography》2022,16(5):397-403
BackgroundPretest probability (PTP) calculators utilize epidemiological-level findings to provide patient-level risk assessment of obstructive coronary artery disease (CAD). However, their limited accuracies question whether dissimilarities in risk factors necessarily result in differences in CAD. Using patient similarity network (PSN) analyses, we wished to assess the accuracy of risk factors and imaging markers to identify ≥50% luminal narrowing on coronary CT angiography (CCTA) in stable chest-pain patients.MethodsWe created four PSNs representing: patient characteristics, risk factors, non-coronary imaging markers and calcium score. We used spectral clustering to group individuals with similar risk profiles. We compared PSNs to a contemporary PTP score incorporating calcium score and risk factors to identify ≥50% luminal narrowing on CCTA in the CT-arm of the PROMISE trial. We also conducted subanalyses in different age and sex groups.ResultsIn 3556 individuals, the calcium score PSN significantly outperformed patient characteristic, risk factor, and non-coronary imaging marker PSNs (AUC: 0.81 vs. 0.57, 0.55, 0.54; respectively, p ?< ?0.001 for all). The calcium score PSN significantly outperformed the contemporary PTP score (AUC: 0.81 vs. 0.78, p ?< ?0.001), and using 0, 1–100 and ?> ?100 cut-offs provided comparable results (AUC: 0.81 vs. 0.81, p ?= ?0.06). Similar results were found in all subanalyses.ConclusionCalcium score on its own provides better individualized obstructive CAD prediction than contemporary PTP scores incorporating calcium score and risk factors. Risk factors may not be able to improve the diagnostic accuracy of calcium score to predict ≥50% luminal narrowing on CCTA. 相似文献
9.
《The Journal of thoracic and cardiovascular surgery》2023,165(2):449-459.e4
ObjectiveThe objective of this study was to investigate the association between morphological variation and postsurgical pulmonary vein (PV) stenosis (PPVS) in patients with cardiac total anomalous pulmonary venous connection (TAPVC).MethodsThis single-center, retrospective study included 168 pediatric patients who underwent surgical repair of cardiac TAPVC from 2013 to 2019 (connection to the coronary sinus [CS], n = 136; connection directly to the right atrium [RA], n = 32). Three-dimensional computed tomography modeling and geometric analysis were performed to investigate the morphological features; their relevance to the PPVS was examined.ResultsThe connection type had no association with PPVS (CS type: 18% vs right atrial type: 19%; P = .89) but there was a higher incidence of PPVS in patients with a single PV orifice than > 1 orifice (P < .001). Confluence-to-total PV area ratio (hazard ratio, 4.78, 95% CI, 1.86-12.32; P = .001) and length of drainage route (hazard ratio, 1.22; 95% CI, 1.14-1.31; P < .001) had a 4- and 1-fold increase in the risk for PPVS in the CS type after adjustment for age and preoperative pulmonary venous obstruction. In the right atrial type, those with anomalous PV return to the RA roof were more likely to develop PPVS than to the posterior wall of the RA (P < .001).ConclusionsThe number of inter-junction PV orifice correlated with PPVS development in cardiac TAPVC. The confluence-to-total PV ratio, length of drainage route, and anomalous PV return to the RA roof are important predictors for PPVS. Morphological subcategorization in this clinical setting can potentially assist in surgical decision-making. 相似文献
10.
《The British journal of oral & maxillofacial surgery》2022,60(8):1118-1124
The aim of this paper was to evaluate the association between ‘asymptomatic or mildly symptomatic’ severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (AS/MS-COVID) and surgical site infection (SSI) after repair of craniomaxillofacial injury (CMFI). Using a case-control study design with a match ratio of 1:4, we enrolled a cohort of AS/MS-COVID cases with immediately treated CMFI during a one-year period. The main predictor variable was SARS-CoV-2 infection (yes/no), and the outcome of interest was SSI (yes/no). The other variables were demographic, clinical, and operative. Appropriate statistics were computed, and p<0.05 was considered statistically significant. The study group comprised 257 cases (28.8% female; 13.2% aged ≥ 60 years; 10.5% with fractures; 39.7% with involvement of nasal/oral/orbital tissue [viral reservoir organs, VROs]; 81.3% with blunt trauma; 19.1% developed an SSI [vs 6.8% in the control group]) with a mean (SD) age of 39.8 (16.6) years (range 19–87). There was a significant relation between SARS-CoV-2 infection and SSI events (p<0.0001; odds ratio 3.22; 95% confidence interval 2.17 to 4.78). On subgroup analysis, SSIs significantly increased with age ≥ 60 years, presence and treatment of fracture, contact with VROs, and prolonged antibiotic use (PAU). However, multivariate logistic regression analysis confirmed a positive effect only from old age, contact with VROs, and PAU (relative risk = 1.56, 2.52, and 2.03, respectively; r = 0.49; p = 0.0001). There was a significant 2.8-fold increase in SSIs among AS/MS-COVID cases, especially in those aged ≥ 60 years, or those with injuries to VROs, or both, who therefore required PAU. 相似文献