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   160140篇
  免费   14000篇
  国内免费   7267篇
耳鼻咽喉   1007篇
儿科学   4696篇
妇产科学   3394篇
基础医学   19522篇
口腔科学   3508篇
临床医学   13821篇
内科学   26418篇
皮肤病学   3100篇
神经病学   12838篇
特种医学   2752篇
外国民族医学   46篇
外科学   12760篇
综合类   23798篇
现状与发展   36篇
预防医学   10233篇
眼科学   3744篇
药学   19568篇
  44篇
中国医学   5245篇
肿瘤学   14877篇
  2024年   262篇
  2023年   2073篇
  2022年   3594篇
  2021年   5919篇
  2020年   5117篇
  2019年   4724篇
  2018年   4673篇
  2017年   5209篇
  2016年   5413篇
  2015年   5729篇
  2014年   9632篇
  2013年   11935篇
  2012年   9636篇
  2011年   10882篇
  2010年   8959篇
  2009年   8704篇
  2008年   9108篇
  2007年   8952篇
  2006年   8166篇
  2005年   7309篇
  2004年   6138篇
  2003年   5319篇
  2002年   4465篇
  2001年   3799篇
  2000年   3280篇
  1999年   2800篇
  1998年   2464篇
  1997年   2237篇
  1996年   1980篇
  1995年   1780篇
  1994年   1523篇
  1993年   1270篇
  1992年   1091篇
  1991年   920篇
  1990年   892篇
  1989年   699篇
  1988年   550篇
  1987年   450篇
  1986年   426篇
  1985年   635篇
  1984年   525篇
  1983年   347篇
  1982年   438篇
  1981年   310篇
  1980年   265篇
  1979年   175篇
  1978年   148篇
  1977年   119篇
  1976年   116篇
  1975年   73篇
排序方式: 共有10000条查询结果,搜索用时 312 毫秒
81.
Nilotinib is a specific breakpoint cluster region-Abelson leukemia virus-tyrosine kinase inhibitor that is used as an effective first- or second-line treatment in imatinib-resistant chronic myelogenous leukemia (CML) patients. Hepatotoxicity due to nilotinib is a commonly reported side effect; however, abnormal liver function test (LFT) results have been reported in asymptomatic cases. When alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels are more than five-fold the upper limit of the normal (ULN) or when the serum total bilirubin level is more than three-fold the ULN, dose modification or discontinuation of nilotinib is recommended, resulting in decreased levels of hematological indicators in certain patients with CML. Nilotinib-induced hyperbilirubinemia typically manifests as indirect bilirubinemia without elevated ALT or AST levels. Such abnormal liver functioning is thus not attributed to the presence of a true histologic lesion of the liver. The underlying mechanism may be related to the inhibition of uridine diphosphate glucuronosyltransferase activity. Therefore, nilotinib dose adjustment is not recommended for this type of hyperbilirubinemia, and in the absence of elevated liver enzyme levels or presence of abnormal LFT findings, physicians should consider maintaining nilotinib dose intensity without modifications.  相似文献   
82.
83.

Objective

Hypertonic saline (HTS) has potent immune and vascular effects. We assessed recipient pretreatment with HTS on allograft function in a porcine model of heart transplantation and hypothesized that HTS infusion would limit endothelial and left ventricular (LV) dysfunction following transplantation.

Methods

Heart transplants were performed after 6 hours of cold ischemic storage. Recipient pigs were randomized to treatment with or without HTS (7.5% NaCl) before cardiopulmonary bypass (CPB). Using a myograft apparatus, coronary artery endothelial-dependent (Edep) and -independent (Eind) relaxation was assessed. LV performance was determined using pressure-volume loop analysis. Pulmonary interleukin (IL)-2, IL-6, and tumor necrosis factor (TNF)-α expression was measured.

Results

Weaning from CPB and LV performance after transplantation were improved in HTS-treated animals. Successful weaning from CPB was greater in the HTS-treated hearts (8 of 8 vs 2 of 8; P < .05). Mean LV functional recovery was improved in the HTS-treated animals, as assessed by preload recruitable stroke work (65 ± 10% vs 27 ± 10%; P < .001) and end-systolic elastance (55 ± 7% vs 37 ± 4%; P < .001). Treatment with HTS resulted in improved Edep (mean maximum elastance [Emax], 56 ± 5% vs 37 ± 7%; P < .001) and Eind (mean Emax%, 77 ± 6% vs 52 ± 4%; P < .001) vasorelaxation compared with control. Pulmonary expression of IL-2, IL-6, and TNF-α increased following transplantation, whereas HTS therapy attenuated IL production (P < .001). Transplantation increased plasma TNF-α levels and LV TNF-α expression, whereas HTS prevented this up-regulation (P < .001).

Conclusions

Recipient HTS pretreatment preserves allograft vasomotor and LV function, and HTS therapy limits CPB-induced injury. HTS may be a novel recipient intervention to prevent graft dysfunction.  相似文献   
84.
85.
86.

Background

Acute myocardial infarction (AMI) causes irreversible myocardial damage and release of inflammatory mediators, including cytokines, chemokines and miRNAs. We aimed to investigate changes in the levels of cytokines (IL-6, TNF-α and IL-10), miRNAs profiles (miR-146 and miR-155) and distribution of different monocyte subsets (CD14++CD16-, CD14++CD16+, CD14+CD16++) in the acute and post-healing phases of AMI.

Methods

In eighteen consecutive AMI patients (mean age 56.78?±?12.4 years, mean left ventricle ejection fraction – LVEF: 41.9?±?9.8%), treated invasively, monocyte subsets frequencies were evaluated (flow cytometry), cytokine concentrations were analyzed (ELISA) as well as plasma miRNAs were isolated twice – on admission and after 19.2?±?5.9 weeks of follow-up. Measurements were also performed among healthy volunteers.

Results

AMI patients presented significantly decreased frequencies of classical cells in comparison to healthy controls (median 71.22% [IQR: 64.4–79.04] vs. 84.35% [IQR: 81.2–86.7], p?=?0.001) and higher percent of both intermediate and non-classical cells, yet without statistical significance (median 6.54% [IQR: 5.14–16.64] vs. 5.87% [IQR: 4.48–8.6], p?=?0.37 and median 5.99% [IQR: 3.39–11.5] vs. 5.26% [IQR: 3.62–6.2], p?=?0.42, respectively). In AMI patients both, analyzed plasma miRNA concentrations were higher than in healthy subjects (miR-146: median 5.48 [IQR: 2.4–11.27] vs. 1.84 [IQR: 0.87–2.53], p?=?0.003; miR-155: median 25.35 [IQR: 8.17–43.15] vs. 8.4 [IQR: 0.08–16.9], p?=?0.027, respectively), and returned back to the values found in the control group in follow-up. miR-155/miR-146 ratio correlated with the frequencies of classical monocytes (r=0.6, p?=?0.01) and miR-155 correlated positively with the concentration of inflammatory cytokines ? IL-6 and TNF-α.

Conclusions

These results may suggest cooperation of both pro-inflammatory and anti-inflammatory signals in AMI in order to promote appropriate healing of the infarcted myocardium.  相似文献   
87.
Accurately predicting the hepatic clearance of compounds using in vitro to in vivo extrapolation (IVIVE) is crucial within the pharmaceutical industry. However, several groups have recently highlighted the serious error in the process. Although empirical or regression-based scaling factors may be used to mitigate the common underprediction, they provide unsatisfying solutions because the reasoning behind the underlying error has yet to be determined. One previously noted trend was intrinsic clearance-dependent underprediction, highlighting the limitations of current in vitro systems. When applying these generated in vitro intrinsic clearance values during drug development and making first-in-human dose predictions for new chemical entities though, hepatic clearance is the parameter that must be estimated using a model of hepatic disposition, such as the well-stirred model. Here, we examine error across hepatic clearance ranges and find a similar hepatic clearance-dependent trend, with high clearance compounds not predicted to be so, demonstrating another gap in the field.  相似文献   
88.
Severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) has a high death rate in patients with comorbidities or in an immunocompromised state. We report a mild and attenuated SARS CoV-2 infection in a patient who is 17 months post stem cell transplantation and maintained on the JAK/STAT inhibitor ruxolitinib, a proposed novel therapy for SARS CoV-2 pneumonia.  相似文献   
89.
目的 探究黄石、荆门地区产后妇女母乳喂养自我效能的现状及影响因素,为改善母乳喂养率提供更多理论依据。方法 对2017年12月—2018年3月在湖北省黄石市、荆门市的三所医院住院分娩的产妇进行问卷调查,获得产妇社会人口特征、孕产相关资料、母乳喂养相关情况。采用多元线性回归分析母乳喂养自我效能的影响因素。结果 共1 023名产妇纳入分析,平均年龄(29.0±5.7)岁。已婚占98.3%,初产占54.0%,大专及以上学历占53.9%。研究对象的母乳喂养自我效能平均得分为(45.5±12.3)分。多元线性回归的结果显示:当前不存在乳腺问题(B=2.08,P=0.036)、有母乳喂养经历(B=3.62,P<0.001)、家人提供母乳喂养指导或经验(B=3.20,P=0.001)、丈夫支持母乳喂养(B=5.87,P=0.001)及产后30 min内有医护母乳喂养帮助(B=3.02,P=0.003)的产妇母乳喂养自我效能得分更高。结论 产后妇女的母乳喂养自我效能可能与其健康状况、母乳喂养经历、社会支持及母乳喂养卫生服务有关。应对产后妇女提供广泛的社会支持,加强母乳喂养卫生服务提供,以提高其母乳喂养的自我效能,促进母乳喂养。  相似文献   
90.
Serum eye drops (SED) have shown beneficial effects in patients suffering from dry eye syndrome and are manufactured for an increasing number of patients in Australia every year. Previous studies have examined the stability of serum growth factors during storage in either experimental vessels not used as the final packaging system or in eye drop bottles. To ensure the quality and safety of SED product manufactured in Australia, the stability of growth factors in serum packaged into two different systems during storage at different temperatures was examined. Healthy blood donors provided a whole blood donation, from which serum was prepared, diluted to 20% and dispensed into either a tube or a vial packaging system. The stability of growth factors, fibronectin and total protein in tube segments was comparable to matched vials samples during storage at −30 °C, 4 °C, 22 °C and 37 °C, with the exception of EGF and fibronectin in 20% SED stored in tube segments, which were more sensitive to storage conditions at 4 °C and 22 °C when compared to vials. Additionally, the growth factor, fibronectin and total protein concentration in both tube segments and vials was stable during storage at −30 °C for at least 9 months. This study highlights the impact of different manufacturing procedures on serum growth factor stability during storage.  相似文献   
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