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   40881篇
  免费   3921篇
  国内免费   2956篇
耳鼻咽喉   309篇
儿科学   597篇
妇产科学   490篇
基础医学   3740篇
口腔科学   575篇
临床医学   5595篇
内科学   5103篇
皮肤病学   374篇
神经病学   1619篇
特种医学   1365篇
外国民族医学   17篇
外科学   3282篇
综合类   8773篇
现状与发展   26篇
一般理论   1篇
预防医学   3614篇
眼科学   1017篇
药学   5211篇
  51篇
中国医学   3089篇
肿瘤学   2910篇
  2024年   159篇
  2023年   561篇
  2022年   1474篇
  2021年   1850篇
  2020年   1466篇
  2019年   1186篇
  2018年   1190篇
  2017年   1302篇
  2016年   1133篇
  2015年   1833篇
  2014年   2317篇
  2013年   2393篇
  2012年   3630篇
  2011年   3711篇
  2010年   2739篇
  2009年   2231篇
  2008年   2645篇
  2007年   2585篇
  2006年   2373篇
  2005年   2188篇
  2004年   1511篇
  2003年   1452篇
  2002年   1154篇
  2001年   873篇
  2000年   841篇
  1999年   637篇
  1998年   382篇
  1997年   337篇
  1996年   285篇
  1995年   241篇
  1994年   206篇
  1993年   116篇
  1992年   113篇
  1991年   103篇
  1990年   116篇
  1989年   70篇
  1988年   73篇
  1987年   61篇
  1986年   65篇
  1985年   40篇
  1984年   17篇
  1983年   14篇
  1981年   9篇
  1980年   9篇
  1979年   8篇
  1976年   5篇
  1974年   6篇
  1973年   9篇
  1972年   5篇
  1970年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
目的探讨老年肺癌的外科治疗体会。方法回顾性研究68例65岁以上老年肺癌的临床资料和治疗情况。结果术前ECG异常21例(30.9%),肺功能异常25例(36.8%)。手术切除66例(97.1%)。术后心肺并发症23.5%,死亡率0。结论老年不应是手术禁忌证,加强围手术期管理,采取适当的手术方式,可以提高老年肺癌患者的生存率。  相似文献   
72.
目的:研究流动注射-CCD二极管阵列检测分光光度法测定尿中肌酐含量的方法。方法:基于经典的Jaffe反应,肌酐能与碱性苦味酸生成橙红色复合物,利用化学动力学反应,采用CCD二极管阵列检测装置快速测定尿中肌酐的含量。本实验探讨了最佳反应条件和流动注射分析参数。结果:本方法的线性范围为1μg/ml~33μg/ml,检出限为1μg/ml。样品的加标回收率在81.63%~119.7%之间,精密度为2.74%~3.96%。将本方法与临床自动生化仪的测定结果比较,经t检验(t=0.179,P〉0.05),两种方法测定结果无统计学差异。结论:本方法采样频率为20次/11,简便快速、分析成本低,实现了尿中肌酐含量的批样分析,获得了满意的结果。  相似文献   
73.
AIM: To observe the effects of three cytokines on the apoptosis of Tf-1 cells induced by y irradiation and investigate the relationship between apoptosis and caspase-3 activity. METHODS: Different cytokines GM-CSF, IL-3 and GM-CS/IL-3 fusion protein were added into the irradiated Tf-1 cells. MTT assay, morphology, flow cytometry, and DNA fragmentation assay were used to observe the effects of cytokines on apoptosis. The caspase-3 activity was determined with a fluorocytometer. RESULTS: Irradiated Tf-1 cells showed typical morphological characteristic of apoptosis demonstrated by transmission electron microscopy and were accumulated in G0/G1 phase. In the groups treated with growth factors after irradiation, three cytokines significantly increased the viability rate, distinctly decreased the apoptosis rate and the proportion of DNA fragmentation. When Tf-1 cells were irradiated by y  相似文献   
74.
ObjectiveTo analyze the use of packed red blood cells (PRBCs) for patients with pelvic fracture and evaluate factors associated with PRBC transfusion for patients with pelvic fracture.MethodsThis retrospective cohort study collected 551 patients with pelvic fractures from six hospitals between September 1, 2012, and June 31, 2019. The age span of patients varied from 10 to 95 years old, and they were classified into two groups based on high‐energy pelvic fractures (HE‐PFs) or low‐energy pelvic fractures (LE‐PFs). The study''s outcome was the use of PRBCs, fresh frozen plasma (FFP), and albumin. Demographic data, characteristics, laboratory tests, clinical treatment details, and clinical outcomes were compared between the two groups. Factors that were statistically associated with perioperative PRBCs in univariate analyses were included to conduct an optimal scale regression to determine the independent factors for perioperative PRBCs.ResultsA total of 551 patients were screened from six hospitals, and after inclusion and exclusion, 319 were finally included and finished the follow‐up from admission to discharge, while four patients died during hospitalization. Three hundred and nineteen patients were classified into two groups by their injury mechanisms. A total of 230/319 (72.1%) patients were classified into the HE‐PF group, and 89/319 (27.8%) patients were classified into the LE‐PF group. Patients in the HE‐PF group were transfused with 4.5 (3–8) units of PRBCs, 300 (0–600) ml of FFP, and 0 (0–30) g of albumin, while patients in the LE‐PF group were transfused with 3.5 (2–4.5) units of PRBCs, 0 (0–295) ml of FFP, and 0 (0–0) g of albumin (all P < 0.001). There were higher proportions of male patients and patients under 65 in the HE‐PF group (all P < 0.001). HE‐PF group patients were more severely injured and likely to take external fixation. The optimal scale regression revealed four significant factors associated with perioperative transfused PRBCs, which were patients on admission with hemorrhagic shock (importance = 0.283, P = 0.004), followed by fracture types identified by Tile classification (importance = 0.156, P < 0.001), hemoglobin levels below 70 g/L on admission (importance = 0.283, P = 0.004), followed by fracture types identified by Tile classification (importance = 0.156, P < 0.001), hemoglobin levels below 70 g/L on admission (importance = 0.148, P = 0.039), and methods of pelvic fixation (importance = 0.008, P = 0.026), ranked by the importance.ConclusionPatients with HE‐PFs had increased transfusions of PRBCs, FFP, and albumin, and hemorrhagic shock on admission, Tile classification, Hb levels, and stabilization methods were found to be associated with perioperative PRBCs.  相似文献   
75.
ObjectivesIn geriatric acetabular fractures, the quadrilateral surface (QLS) was frequently involved in acetabular fracture patterns and accompanied by medial displacement. It was important to buttress the medial displaced QLS and reconstruct the congruity of the affected acetabulum. To evaluate the clinical effectiveness of the novel infra‐pectineal quadrilateral surface buttress plates for the treatment of geriatric acetabular fractures.MethodsTwenty‐three geriatric patients who were treated for acetabular fractures involving QLS with the novel infra‐pectineal buttress plates (NIBP) through a single supra‐ilioinguinal approach between January 2015 and June 2019 were retrospectively analyzed; all patients received at least 1 year''s follow‐up. All patients were aged ≥60 years old and including 18 males and five females. Radiologic and clinical outcomes of patients involved in the study were collated and analyzed according to the Matta scoring system and the Merle D''Aubigné–Postel scoring system. The functional recovery scoring was compared using q‐test.ResultsAll 23 consecutive patients had relatively satisfactory clinical treatment effectiveness. Average ages, length of incision, operation time, and intraoperative blood loss were 69.8 ± 6.1 years, 12.1 ± 2.6 cm, 166.5 ± 43.5 min, and 500 (500,700) ml, respectively. According to the Matta scoring system, 14 cases of reduction were graded as excellent, five as good, and four as fair. At the last follow‐up, the clinical outcome evaluation was excellent in 13 cases, good in seven cases, and poor in three cases with the use of the Merle D''Aubigné–Postel scoring system. The difference of modified Merle D''Aubigne‐Postel score at 3 months, 6 months and last follow up was statistically significant (F = 21.56, p < 0.05). Postoperative lateral femoral cutaneous nerve injury occurred in three patients and heterotopic ossification occurred in one patient.ConclusionsFor the treatment of geriatric acetabular fractures, the NIBP could provide stable and effective fixation to the QLS involved acetabular fractures, and related satisfactory clinical results with few complications were noted.  相似文献   
76.
Axitinib is a potent vascular endothelial growth factor receptor (VEGFR) inhibitor, which has a strong inhibitory effect on the three isoforms of VEGFR 1–3. Having strong therapeutic efficacy, its broad use is limited by its side effects such as hypertension, proteinuria, cardiovascular damage, and liver and kidney dysfunction. Selenium compounds are broadly reported to have a good protective effect on cardiovascular disease, inflammation, infection, and immune function. In this study, a selenium substitute of axitinib was synthesized, and its anti-renal cell carcinoma activity and side effects were investigated. The results of the study indicated that Se-axitinib had potent antitumor activity on renal cell carcinoma (RCC), alleviated vascular hyperpermeability, and also alleviated axitinib-related side effects including hypertension, liver dysfunction and kidney dysfunction significantly. Therefore, we suggest that Se-axitinib could be a solution to the severe side effects of VEGFR inhibitors and provide evidence to improve the outcome of RCC treatment.

Se-axitinib is a selenium substitution of sulfur in axitinib, which reduced the side effect of VEGFR inhibitors and maintained the potent anticancer activity of the original drug.  相似文献   
77.
目的:研究血管内皮生长因子受体(VEGFR3)在舌癌淋巴转移中的作用,探索舌癌淋巴转移的机制。方法:采用免疫组化和RT-PCR技术,对90例不同分期的舌癌肿瘤进行VEGFR3的检测,与10例正常舌黏膜标本进行对照。采用SAS6.12软件进行单因素方差分析。结果:通过与正常组对照,Ⅰ、Ⅱ、Ⅲ期肿瘤中VEGFR3的表达无显著性差异(P>0.05),Ⅳ期肿瘤中VEGFR3的表达较正常对照组显著升高并具有显著性差异(P<0.05)。肿瘤各组间比较无显著性差异。转移组与非转移组之间也无显著性差异。结论:VEGFR3参与微淋巴管的生成,随着肿瘤的临床分期增高,其表达虽呈缓慢增高趋势,但尚不足以作为判定是否发生淋巴转移的客观指标。  相似文献   
78.
印迹基因Snrpn在人类卵母细胞及植入前胚胎mRNA表达   总被引:1,自引:0,他引:1  
目的了解印迹基因Snrpn在人类卵母细胞和植入前胚胎的表达,以分析Snrpn基因表达对人类卵母细胞和早期胚胎发育的影响。方法采用单细胞巢式逆转录多聚酶链式反应(Single Cell Nested RT-PCR)方法,检测人类卵子和植入前各个阶段胚胎的印迹基因Snrpn mRNA表达情况。结果Snrpn在人类卵母细胞GV、MI、MII和植入前胚胎2、4、6、8细胞期都有表达,单卵母细胞扩增成功率为87.5%,单个胚胎为75.8%,平均扩增成功率为79.1%。单个卵母细胞和单个卵裂球扩增成功率无显著性差异(P>0.05),但单卵母细胞较单个卵裂球高。结论建立了比较稳定、可靠的单细胞巢式RT-PCR技术检测基因表达。印迹基因Snrpn在人类卵细胞和植入前胚胎的表达对卵子生长和胚胎发育有着重要意义,为早期胚胎阶段该基因表达正常图谱提供实验依据  相似文献   
79.
目前,市县级医院普遍采用固相酶联免疫法(ELISA)检测乙肝5项指标,该法操作方便、快捷,特别适合大批标本的筛查。但由于ELISA方法学特点,批内批间的CV值较大。因此,做好该项检测的质量控制是保证结果真实可靠的基础。现就本室开展此项室内质控若干措施和体会报告如下。  相似文献   
80.
ObjectiveTo evaluate the effect of different levels of physician experience on the high-intensity focused ultrasound (HIFU) ablation of uterine fibroids and to provide a reference for the use of non-perfused volume ratio (NPVR) standards during training.MethodsThis prospective multicentre study enrolled patients with uterine fibroids. The effect of the physician’s level of experience on the outcomes under different NPVR standards and the learning curve of six centres without HIFU experience were analysed. The impact of patient demographic and clinical characteristics were also evaluated.ResultsA total of 1352 patients from 20 centres were included in the study. The median NPVRs were 92.00%, 88.10% and 92.86% in the no experience group, inexperienced group and experienced group, respectively. Posterior wall fibroids, lateral wall fibroids and fundus fibroids were inversely correlated with NPVR, while experienced physicians were positively correlated with NPVR. With NPVR ≥ 70% and NPVR ≥ 80% standards, physicians in the no experience group completed the learning curve on the 11th and 16th procedure, respectively. Physicians under a standard of an NPVR ≥ 90% did not complete the learning curve.ConclusionsNPVR ≥ 80% is a standard that is worth using for HIFU treatment of uterine fibroids.  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