首页 | 官方网站   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   4969884篇
  免费   395522篇
  国内免费   18344篇
医药卫生   5383750篇
  2021年   58133篇
  2019年   60785篇
  2018年   77940篇
  2017年   59283篇
  2016年   65497篇
  2015年   78003篇
  2014年   112152篇
  2013年   178678篇
  2012年   146438篇
  2011年   155060篇
  2010年   133655篇
  2009年   132749篇
  2008年   139936篇
  2007年   149876篇
  2006年   157200篇
  2005年   150919篇
  2004年   151178篇
  2003年   140635篇
  2002年   129374篇
  2001年   194757篇
  2000年   191470篇
  1999年   172769篇
  1998年   75771篇
  1997年   70576篇
  1996年   68761篇
  1995年   64022篇
  1994年   58069篇
  1993年   53621篇
  1992年   126893篇
  1991年   121871篇
  1990年   117442篇
  1989年   113939篇
  1988年   105006篇
  1987年   102945篇
  1986年   97488篇
  1985年   94773篇
  1984年   76942篇
  1983年   68004篇
  1982年   51316篇
  1981年   47038篇
  1980年   44010篇
  1979年   66678篇
  1978年   52297篇
  1977年   45722篇
  1976年   42799篇
  1975年   43407篇
  1974年   48550篇
  1973年   46566篇
  1972年   43765篇
  1971年   40656篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Background: Thyrosin kinase inhibitors (TKIs) is approved for the first line treatment of non-small cell lung cancer (NSCLC) patients with  epidermal growth factor receptor (EGFR) mutation. This study performed to assess clinical effectiveness and safety of Erlova (generic form of Erlotinib). Methods: Somatic mutations of EGFR gene were studied in tumor tissue by polymerase chain reaction (PCR) and bi-directional sequencing in 513 chemonaive and histologically verified lung adenocarcinoma Iranian patients. Patients  with EGFR mutation received Erlova at 150 mg/day  as first line treatment. Primary endpoint was progression free survival (PFS). Results: About 21% (n=109) cases had EGFR mutation. Most EGFR mutations were  occurred at exon 19. Among them, sixty nine patients treated with Erlova. Median PFS was 11.4 months and objective response rate (ORR) was about  88%. Most frequent treatment related adverse events was  skin rash. Conclusion: Our findings showed Erlova had remarkable effectiveness. In  mutation-positive patients with EGFR, Erlova can be used  safely instead of  other tyrosine-kinase inhibitors.  相似文献   
73.
74.
75.
Gestational trophoblastic neoplasia (GTN) patients are treated according to the eight-variable International Federation of Gynaecology and Obstetrics (FIGO) scoring system, that aims to predict first-line single-agent chemotherapy resistance. FIGO is imperfect with one-third of low-risk patients developing disease resistance to first-line single-agent chemotherapy. We aimed to generate simplified models that improve upon FIGO. Logistic regression (LR) and multilayer perceptron (MLP) modelling (n = 4191) generated six models (M1-6). M1, all eight FIGO variables (scored data); M2, all eight FIGO variables (scored and raw data); M3, nonimaging variables (scored data); M4, nonimaging variables (scored and raw data); M5, imaging variables (scored data); and M6, pretreatment hCG (raw data) + imaging variables (scored data). Performance was compared to FIGO using true and false positive rates, positive and negative predictive values, diagnostic odds ratio, receiver operating characteristic (ROC) curves, Bland-Altman calibration plots, decision curve analysis and contingency tables. M1-6 were calibrated and outperformed FIGO on true positive rate and positive predictive value. Using LR and MLP, M1, M2 and M4 generated small improvements to the ROC curve and decision curve analysis. M3, M5 and M6 matched FIGO or performed less well. Compared to FIGO, most (excluding LR M4 and MLP M5) had significant discordance in patient classification (McNemar's test P < .05); 55-112 undertreated, 46-206 overtreated. Statistical modelling yielded only small gains over FIGO performance, arising through recategorisation of treatment-resistant patients, with a significant proportion of under/overtreatment as the available data have been used a priori to allocate primary chemotherapy. Streamlining FIGO should now be the focus.  相似文献   
76.
目的:探讨环状RNA hsa_circ_0006867在结直肠癌中的表达及其与临床病理因素的关系。方法:全转录组测序筛选结直肠癌中特异circRNAs表达谱,挑选出差异表达显著的hsa_circ_0006867,qRT-PCR检测54例结直肠癌组织及癌旁组织中hsa_circ_0006867表达情况,分析其表达水平与结直肠癌临床病理特征的相关性,ROC曲线分析hsa_circ_0006867在结直肠癌中的诊断价值。结果:测序获得circRNAs在结直肠癌中的差异表达谱,qRT-PCR验证hsa_circ_0006867在结直肠癌中表达下调(P<0.05)。其表达水平与肿瘤分化程度和远处转移有关(P<0.05)。ROC曲线显示hsa_circ_0006867诊断结直肠癌AUC为0.851(95%CI:0.775~0.927),当截断值为0.0146时,敏感度为88.46%(95%CI:0.770~0.946),特异度为73.08%(95%CI:0.598~0.832),差异具有统计学意义(P<0.001)。结论:hsa_circ_0006867在结直肠癌中表达下调,与相关临床病理特征密切联系,可作为潜在结直肠癌临床诊断指标。  相似文献   
77.
Heart Failure Reviews - The nitric oxide (NO)–guanylate cyclase (GC)–cyclic guanosine monophosphate (cGMP) pathway plays an important role in cardiovascular, pulmonary and renal...  相似文献   
78.
Comprehensive evidence regarding the treatment of non-anaemic iron deficiency in patients undergoing valvular heart surgery is lacking. This study aimed to investigate the association between non-anaemic iron deficiency and postoperative outcomes in these patients. We retrospectively analysed 321 patients of which 180 (56%) had iron deficiency (defined as serum ferritin < 100 ng.ml-1 or < 300 ng.ml-1 with transferrin saturation < 20%). While the iron-deficient group had lower pre-operative haemoglobin levels than the non-iron deficient group (median (IQR [range]) 134 (127–141 [120–172]) g.l-1, 143 (133–150 [120–179]) g.l-1, p = 0.001), there was no between-group difference in allogeneic red blood cell transfusion. Median (IQR [range]) days alive and out of hospital at postoperative day 90 was 1 day shorter in the iron-deficient group (80 (77–82 [9–85]) days vs. 81 (79–83 [0–85]) days, p = 0.026). In multivariable analysis, only cardiopulmonary bypass duration (p = 0.032) and intra-operative allogeneic red blood cell transfusion (p = 0.011) were significantly associated with reduced days alive and out of hospital at postoperative day 90. Iron deficiency did not exert any adverse influence on secondary outcomes except length of hospital stay. Our findings indicate that non-anaemic iron deficiency alone is not associated with adverse effects in patients undergoing valvular heart surgery when it does not translate into an increased risk of allogeneic transfusion.  相似文献   
79.
Two Janus-associated kinase inhibitors (JAKi) (initially ruxolitinib and, more recently, fedratinib) have been approved as treatment options for patients who have intermediate-risk and high-risk myelofibrosis (MF), with pivotal trials demonstrating improvements in spleen volume, disease symptoms, and quality of life. At the same time, however, clinical trial experiences with JAKi agents in MF have demonstrated a high frequency of discontinuations because of adverse events or progressive disease. In addition, overall survival benefits and clinical and molecular predictors of response have not been established in this population, for which the disease burden is high and treatment options are limited. Consistently poor outcomes have been documented after JAKi discontinuation, with survival durations after ruxolitinib ranging from 11 to 16 months across several studies. To address such a high unmet therapeutic need, various non-JAKi agents are being actively explored (in combination with ruxolitinib in first-line or salvage settings and/or as monotherapy in JAKi-pretreated patients) in phase 3 clinical trials, including pelabresib (a bromodomain and extraterminal domain inhibitor), navitoclax (a B-cell lymphoma 2/B-cell lymphoma 2-xL inhibitor), parsaclisib (a phosphoinositide 3-kinase inhibitor), navtemadlin (formerly KRT-232; a murine double-minute chromosome 2 inhibitor), and imetelstat (a telomerase inhibitor). The breadth of data expected from these trials will provide insight into the ability of non-JAKi treatments to modify the natural history of MF.  相似文献   
80.
Journal of Immigrant and Minority Health - COVID-19 has disproportionally affected underrepresented minorities (URM) and low-income immigrants in the United States. The aim of the study is to...  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-23

京公网安备 11010802026262号