首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   266851篇
  免费   15795篇
  国内免费   7611篇
耳鼻咽喉   3312篇
儿科学   8962篇
妇产科学   4529篇
基础医学   18964篇
口腔科学   5108篇
临床医学   31606篇
内科学   50686篇
皮肤病学   3263篇
神经病学   11979篇
特种医学   13034篇
外国民族医学   24篇
外科学   42877篇
综合类   26666篇
现状与发展   27篇
一般理论   1篇
预防医学   17799篇
眼科学   5295篇
药学   27345篇
  188篇
中国医学   6647篇
肿瘤学   11945篇
  2023年   2859篇
  2022年   5167篇
  2021年   11355篇
  2020年   7516篇
  2019年   12820篇
  2018年   7430篇
  2017年   6397篇
  2016年   8400篇
  2015年   11315篇
  2014年   21204篇
  2013年   18891篇
  2012年   21544篇
  2011年   18958篇
  2010年   16953篇
  2009年   16450篇
  2008年   15119篇
  2007年   14978篇
  2006年   12702篇
  2005年   8793篇
  2004年   4994篇
  2003年   4317篇
  2002年   3462篇
  2001年   2862篇
  2000年   2437篇
  1999年   1668篇
  1998年   1918篇
  1997年   1733篇
  1996年   1460篇
  1995年   1506篇
  1994年   1469篇
  1993年   1178篇
  1992年   1415篇
  1991年   1199篇
  1990年   1215篇
  1989年   1212篇
  1988年   1129篇
  1987年   981篇
  1986年   804篇
  1985年   1765篇
  1984年   1871篇
  1983年   1332篇
  1982年   1450篇
  1981年   1404篇
  1980年   1210篇
  1979年   1041篇
  1978年   815篇
  1977年   801篇
  1976年   695篇
  1975年   462篇
  1974年   474篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Insulin is a potent anabolic hormone, and binding to its receptor activates downstream intracellular signaling pathways that regulate the nutrient metabolism, fluid homeostasis, growth, ionic transport, maintenance of vascular tone, and other functions. Insulin resistance (IR) is a condition characterized by subnormal cellular response to physiological levels of insulin. The IR is divided into three types (prereceptor, receptor, and postreceptor) based on the site of pathology. Beta cells attempt to overcome the IR by increasing the release of insulin, leading to hyperinsulinemia. IR is the predisposing factor for many metabolic and cardiovascular disorders. From the evolutionary perspective, the presence of IR offers a survival advantage in the face of starvation or stress. In this brief review, we discuss the different facets of insulin resistance and appraise the readers about the hitherto neglected beneficial advantages.  相似文献   
992.
BACKGROUND Metabolic disturbances including changes in serum calcium,magnesium or phosphate(P) influence the prevalence of type 2 diabetes mellitus(DM).We assessed the importance of serum P in elderly patients with type 2 DM vs nondiabetes mellitus(non-DM) in relation to renal function.AIM To determine the association between serum P and serum glucose or insulin resistance in diabetic and non-diabetic patients.METHODS One hundred-ten subjects with a mean age of 69.02±14.3 years were enrolled.Twenty-nine of the participants had type 2 DM(26.4%).The incidence of hypertension,smoking and receiving vitamin D(vitD) derivates were recorded.The participants were classified by both estimated glomerular filtration rate(eGFR) and albuminuria categories according to the Kidney Disease Improving Global Outcomes 2012 criteria.RESULTS We divided the patients in two groups according to the P cut-off point related to DM value.A comparison between high and low P showed that body mass index30.2±6.3 vs 28.1±4.6(P=0.04),mean glucose 63.6 vs 50.2(P=0.03),uric acid 6.7±1.6 vs 6.09±1.7(P=0.05),mean intact-parathyroid hormone 68.06 vs 47.4(P=0.001),systolic blood pressure 147.4±16.7 vs 140..2±16.1(P=0.02),mean albuminuria 63.2 vs 50.6(P=0.04) and eGFR 45.6±22.1 vs 55.4±21.5(P=0.02)were significantly different.χ~2 tests showed a significant association between high P and DM,hypertension,receiving vitD,smoking and eGFR stage(χ~2=6.3,P=0.01,χ~2=3.9,P=0.03,χ~2=6.9,P=0.009,χ~2=7.04,P=0.01 and χ~2=7.36,P=0.04,respectively).The adjusted model showed that older age,female gender and increased body mass index were significant predictors of type 2 DM when entering the covariates.CONCLUSION High serum P contributes to vascular and metabolic disturbances in elderly patients with type 2 DM and renal impairment.  相似文献   
993.
CT三维重建技术已经广泛应用于骨折诊断及其分型。基于CT三维重建的骨折地图绘制技术,通过绘制骨折模型来直观展现骨折线的形态学,包括骨折线的起止、走行、骨折面积等。骨折地图绘制技术为骨折诊断、骨折分型、治疗方案选择、手术内固定物设计、骨折好发部位统计、骨折标准化模型制定均提供了一个全新的方法。本文将回顾目前国内外包括对于肩胛骨骨折、胫骨远端骨折、尺骨冠状突骨折、胫骨平台骨折、桡骨小头骨折、股骨转子间外侧壁骨折、髋臼四边体骨折等骨折地图的研究进展,归纳总结了以上各个骨折模型的骨折好发部位及骨折地图绘制技术在骨折分型等方面的应用,并探讨骨折地图的临床应用前景及骨折地图绘制技术存在的问题等。  相似文献   
994.
双层探测器光谱CT(SDCT)具有上下两层空间对等的探测器结构,使高、低能2套数据在原始数据域空间即被解析,可用于重建反映康普顿效应和光电效应不同组成的能谱图像,并可合并重建完全等同于普通CT所具有的常规多能图像。SDCT的能谱数据具有同时、同源、同向特征,提升了其在心脏成像中的应用价值。本文对SDCT在改善冠状动脉CTA图像质量、“双低”成像、显示斑块及支架以及心肌灌注方面的应用价值进行综述。  相似文献   
995.
996.
BackgroundCorticosteroids have a negative impact on the human immune system’s ability to function at an optimal level. Studies have shown that patients on long-term corticosteroids have higher infection rates. However, the rates of infection and other complications following lumbar decompression surgery remains under-investigated. The aim of our study was to determine the impact of preoperative long-term corticosteroid usage on acute, 30-day postoperative complications in a subset of patients undergoing lumbar spine decompression surgery, without fusion or instrumentation. We hypothesize that patients on long-term corticosteroids will have higher rates of infection and other postoperative complications after undergoing lumbar decompression surgery of the spine.MethodsA retrospective cohort study was conducted using data collected from the National Surgical Quality Improvement Program database data from 2005 to 2016. Lumbar decompression surgeries, including discectomies, laminectomies, and others were identified using CPT codes. Chi-square analysis was used to evaluate differences among the corticosteroid and non-corticosteroid groups for demographics, preoperative comorbidities, and postoperative complications. Logistic regression analysis was done to determine if long-term corticosteroid use predicts incidence of postoperative infections following adjustment.Results26,734 subjects met inclusion criteria. A total of 1044 patients (3.9%) were on long-term corticosteroids prior to surgical intervention, and 25,690 patients (96.1%) were not on long-term corticosteroids. Patients on long-term corticosteroids were more likely to be older (p < 0.001), female (p < 0.001), nonsmokers (p < 0.001), and have a higher American Society of Anesthesiologist class (p < 0.001). Multivariate analysis demonstrated that long-term corticosteroid usage was associated with increased overall complications (odds ratio [OR]: 1.543; p < 0.001), and an independent risk factor for the development of minor complications (OR: 1.808; p < 0.001), urinary tract infection (OR: 2.033; p = 0.002), extended length of stay (OR: 1.244; p = 0.039), thromboembolic complications (OR: 1.919; p = 0.023), and sepsis complications (OR: 2.032; p = 0.024).ConclusionLong-term corticosteroid usage is associated with a significant increased risk of acute postoperative complication development, including urinary tract infection, sepsis and septic shock, thromboembolic complications, and extended length of hospital stay, but not with superficial or deep infection in patients undergoing lumbar decompression procedures. Spine surgeons should remain vigilant regarding postoperative complications in patients on long-term corticosteroids, especially as it relates to UTI and propensity to decompensate into sepsis or septic shock. Thromboembolic risk attenuation is also imperative in this patient group during the postoperative period and the surgeon should weigh the risks and benefits of more intensive anticoagulation measures.  相似文献   
997.
《Brain stimulation》2022,15(5):1269-1278
BackgroundDeep brain stimulation of the internal globus pallidus (GPi DBS) is an invasive therapeutic modality intended to retune abnormal central nervous system patterns and relieve the patient of dystonic or other motor symptoms.ObjectivesThe aim of the presented research was to determine the neuroanatomical signature of GPi DBS modulation and its association with the clinical outcome.MethodsThis open-label fixed-order study with cross-sectional validation against healthy controls analysed the resting-state functional MRI activity changes induced by GPi DBS in 18 dystonia patients of heterogeneous aetiology, focusing on both global (full brain) and local connectivity (local signal homogeneity).ResultsCompared to the switched-off state, the activation of GPi DBS led to the restoration of global subcortical connectivity patterns (in both putamina, diencephalon and brainstem) towards those of healthy controls, with positive direct correlation over large-scale cortico-basal ganglia-thalamo-cortical and cerebellar networks with the clinical improvement. Nonetheless, on average, GPi DBS also seemed to bring local connectivity both in the cortical and subcortical regions farther away from the state detected in healthy controls. Interestingly, its correlation with clinical outcome showed that in better DBS responders, local connectivity defied this effect and approached healthy controls.ConclusionsAll in all, the extent of restoration of both these main metrics of interest towards the levels found in healthy controls clearly correlated with the clinical improvement, indicating that the restoration of network state towards more physiological condition may be a precondition for successful GPi DBS outcome in dystonia.  相似文献   
998.
999.
Currently, the best treatment strategy for patients with a high‐normal blood pressure (prehypertension) is not known. The authors aimed to determine whether pharmacological reduction of systolic blood pressure (SBP) to a normal level (<120 mm Hg) would prevent cardiac morbidity and mortality in prehypertensive patients. In this secondary analysis, the authors obtained the data from SPRINT from the National Heart, Lung, and Blood Institute data repository center. Among 9361 patients enrolled in SPRINT, 289 high‐risk (ASCVD risk = 24.8% ± 13.0 [10‐65]) prehypertensive patients without previous cardiovascular disease and not receiving any antihypertensive medications were enrolled. One hundred and forty‐eight of them were assigned to standard treatment which consisted of clinical follow‐up till SBP goes above 140 mm Hg and then staring medications to keep SBP <140 mm Hg. One hundred and forty‐one were assigned to the intensive treatment receiving pharmacological SBP reduction to <120 mm Hg upon enrollment. The primary composite outcome was myocardial infarction, and other acute coronary syndromes, stroke, heart failure, or death from cardiovascular causes. Throughout the 3.06 years of follow‐up, a primary outcome event was confirmed in three participants (0.74% per year) in the intensive‐treatment group and 8 (1.61% per year) in the standard‐treatment group (hazard ratio [HR], 0.19; P = .045). Rates of serious adverse events were not increased by intensive‐treatment (HR, 0.83; P = .506). Based on this secondary post hoc analysis, intensive SBP reduction may probably be beneficial for primary prevention of cardiovascular morbidity and mortality in high‐risk prehypertensive patients. This finding needs to be evaluated in a larger trial designed specifically to answer this question.  相似文献   
1000.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号