全文获取类型
收费全文 | 102489篇 |
免费 | 10124篇 |
国内免费 | 5063篇 |
学科分类
医药卫生 | 117676篇 |
出版年
2024年 | 136篇 |
2023年 | 1481篇 |
2022年 | 2418篇 |
2021年 | 4124篇 |
2020年 | 3553篇 |
2019年 | 3418篇 |
2018年 | 3245篇 |
2017年 | 3668篇 |
2016年 | 4124篇 |
2015年 | 4642篇 |
2014年 | 6931篇 |
2013年 | 6196篇 |
2012年 | 6167篇 |
2011年 | 6708篇 |
2010年 | 5355篇 |
2009年 | 5318篇 |
2008年 | 5485篇 |
2007年 | 5723篇 |
2006年 | 5330篇 |
2005年 | 4776篇 |
2004年 | 3807篇 |
2003年 | 3328篇 |
2002年 | 2820篇 |
2001年 | 2705篇 |
2000年 | 2311篇 |
1999年 | 1867篇 |
1998年 | 1676篇 |
1997年 | 1490篇 |
1996年 | 1336篇 |
1995年 | 1139篇 |
1994年 | 1038篇 |
1993年 | 755篇 |
1992年 | 641篇 |
1991年 | 560篇 |
1990年 | 460篇 |
1989年 | 416篇 |
1988年 | 404篇 |
1987年 | 322篇 |
1986年 | 251篇 |
1985年 | 282篇 |
1984年 | 241篇 |
1983年 | 173篇 |
1982年 | 187篇 |
1981年 | 160篇 |
1980年 | 160篇 |
1979年 | 122篇 |
1978年 | 83篇 |
1977年 | 63篇 |
1976年 | 49篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
21.
22.
目的 探究高龄产妇产后抑郁的影响因素,为护理人员今后在临床工作中提供个性化的护理服务提供参考依据。方法 采用质性研究中的现象学研究法对2021年12月至2022年4月在内蒙古医科大学附属医院妇产科建档分娩的16例高龄产妇进行半结构式访谈,并以Colaizzi现象学研究方法进行资料分析。结果 提炼出影响高龄产妇产后抑郁的4个主题:躯体性压力源;负性心理体验;社会支持缺乏,矛盾出现;角色转变对高龄产妇的影响。结论 需重视高龄产妇产后的主观感受,加强产前产后健康宣教,构建以家庭为中心的高龄产妇产后护理模型,减少产后抑郁的发生。 相似文献
23.
《Diabetes & Metabolic Syndrome: Clinical Research & Reviews》2019,13(2):1225-1229
Background and objectivesThe present review shows a list of anti-glycation plants with their anti-glycation activity mechanisms that can attract the attention of pharmacologist for further scientific research towards finding better remedy for diabetic complications.MaterialsGoogle scholar, Pubmed, Web of Science and Scopus were searched. The terms were advanced glycation end products (AGEs), medicinal plants, antiglycation products.Resultsplants that studied in this review inhibit glycation in several possible mechanisms. Some of these plants inhibit the production of shiff base and amadori products. The others inhibit the generation of amadori products in the advanced phase. Some others blocked the aggregation of AGEs and some plants have antioxidant activity and reduce AGEs formation by preventing oxidation of amadori product and metal-catalyzed glucoxidation.ConclusionThis review can help pharmacologist to find antiglycation natural substance that can be useful in treatment of diabetic complications. 相似文献
24.
25.
《Journal of the American College of Radiology》2020,17(10):1207-1219
PurposeLobular neoplasia (LN) detected on breast core needle biopsy is frequently managed with surgical excision because of concern for undersampled malignancy. The authors performed a systematic review and meta-analysis to estimate the risk for upgrade to malignancy in the setting of imaging-concordant classic LN diagnosed on core biopsy.MethodsPubMed and Embase were searched for original articles published from 1998 to 2020 that reported rates of upgrade to malignancy for classic LN, including atypical lobular hyperplasia (ALH) and classic lobular carcinoma in situ (LCIS). Two reviewers extracted study data and assessed the following quality criteria: exclusion of variant LCIS, exclusion of imaging-discordant lesions, and outcome reporting for ≥70% of lesions. For studies meeting all criteria, pooled risks for upgrade to any malignancy (invasive carcinoma or ductal carcinoma in situ) and invasive malignancy for all LN, ALH, and LCIS were estimated using random-effects models.ResultsFor 65 full-text articles included in the review, the risk for upgrade to any malignancy ranged from 0% to 45%. Among the 16 studies that met all quality criteria for the meta-analysis, pooled risks for upgrade to any malignancy were 3.1% (95% confidence interval [CI], 1.8%-5.2%) for all LN, 2.5% (95% CI, 1.6%-3.9%) for ALH, and 5.8% (95% CI, 2.9%-11.3%) for LCIS. Risks for upgrade to invasive malignancy were 1.3% (95% CI, 0.7%-2.4%) for all LN, 0.4% (95% CI, 0.0%-4.2%) for ALH, and 3.5% (95% CI, 2.0%-5.9%) for LCIS.ConclusionsThe risk for upgrade to malignancy for LN found on breast biopsy is low. Imaging surveillance can likely be offered as an alternative to surgical management for LN, particularly for ALH. 相似文献
26.
Hui-Ju Ch’ang 《World journal of hepatology》2015,7(16):2029-2040
The success of sorafenib in prolonging survival of patients with hepatocellular carcinoma (HCC) makes therapeutic inhibition of angiogenesis a component of treatment for HCC. To enhance therapeutic efficacy, overcome drug resistance and reduce toxicity, combination of antiangiogenic agents with chemotherapy, radiotherapy or other targeted agents were evaluated. Nevertheless, the use of antiangiogenic therapy remains suboptimal regarding dosage, schedule and duration of therapy. The issue is further complicated by combination antiangiogenesis to other cytotoxic or biologic agents. There is no way to determine which patients are most likely respond to a given form of antiangiogenic therapy. Activation of alternative pathways associated with disease progression in patients undergoing antiangiogenic therapy has also been recognized. There is increasing importance in identifying, validating and standardizing potential response biomarkers for antiangiogenesis therapy for HCC patients. In this review, biomarkers for antiangiogenesis therapy including systemic, circulating, tissue and imaging ones are summarized. The strength and deficit of circulating and imaging biomarkers were further demonstrated by a series of studies in HCC patients receiving radiotherapy with or without thalidomide. 相似文献
27.
Sevim Turanli Nazan Bozdogan Hakan Mersin Ugur Berberoglu 《The Indian journal of surgery》2015,77(6):489-494
Helicobacter pylori has been associated with diverse pathologies of varying severity. We investigated the H. pylori infection status and its association with the pathologic features and clinical outcomes in stage III gastric cancer patients treated with adjuvant therapy after curative resection. Between 2004 and 2009, the records of 76 consecutive patients were retrospectively reviewed. H. pylori infection was confirmed by examination of pathological specimen. The relationship between H. pylori and the clinicopathological features was analyzed by Fisher exact test, Student’s t test, and Kaplan-Meier method. Of the 76 patients, 16 patients (21.1 %) were confirmed for H. pylori infection. The median age was 59 years. Twenty-three patients received chemotherapy and remainder received chemoradiotherapy. H. pylori status did not correlate with the clinicopathologic features. It was greater in non-neoplastic tissue than the tumor tissue (21.1 vs 7.9 %). Median follow-up was 21 months. During this period, 88.2 % patients had experienced tumor recurrence, and 85.5 % patients had died. Recurrence was observed in 87.5 % patients and in 88.3 % patients in H. pylori-positive and H. pylori-negative patients, respectively (P = 0.92). Disease-free survival was 28.4 ± 7.9 months and overall survival was 31.5 ± 7.4 months in H. pylori-positive patients compared with 28.3 ± 3.7 and 33.2 ± 3.4 months, respectively, in H. pylori-negative patients. H. pylori infection status did not have effect on the overall or disease-free survival (p = 0.85 and P = 0.86), respectively. H. pylori status might not be useful as a prognostic and predictive factor for clinical outcomes. 相似文献
28.
29.
《Diagnostic and interventional imaging》2020,101(12):821-830
PurposeTo compare morphological imaging features and CT texture histogram parameters between grade 3 pancreatic neuroendocrine tumors (G3-NET) and neuroendocrine carcinomas (NEC).Materials and methodsPatients with pathologically proven G3-NET and NEC, according to the 2017 World Health Organization classification who had CT and MRI examinations between 2006-2017 were retrospectively included. CT and MRI examinations were reviewed by two radiologists in consensus and analyzed with respect to tumor size, enhancement patterns, hemorrhagic content, liver metastases and lymphadenopathies. Texture histogram analysis of tumors was performed on arterial and portal phase CT images. images. Morphological imaging features and CT texture histogram parameters of G3-NETs and NECs were compared.ResultsThirty-seven patients (21 men, 16 women; mean age, 56 ± 13 [SD] years [range: 28-82 years]) with 37 tumors (mean diameter, 60 ± 46 [SD] mm) were included (CT available for all, MRI for 16/37, 43%). Twenty-three patients (23/37; 62%) had NEC and 14 patients (14/37; 38%) had G3-NET. NECs were larger than G3-NETs (mean, 70 ± 51 [SD] mm [range: 18 - 196 mm] vs. 42 ± 24 [SD] mm [range: 8 - 94 mm], respectively; P = 0.039), with more tumor necrosis (75% vs. 33%, respectively; P = 0.030) and lower attenuation on precontrast (30 ± 4 [SD] HU [range: 25-39 HU] vs. 37 ± 6 [SD] [range: 25-45 HU], respectively; P = 0.002) and on portal venous phase CT images (75 ± 18 [SD] HU [range: 43 - 108 HU] vs. 92 ± 19 [SD] HU [range: 46 - 117 HU], respectively; P = 0.014). Hemorrhagic content on MRI was only observed in NEC (P = 0.007). The mean ADC value was lower in NEC ([1.1 ± 0.1 (SD)] × 10−3 mm2/s [range: (0.91 - 1.3) × 10−3 mm2/s] vs. [1.4 ± 0.2 (SD)] × 10−3 mm2/s [range: (1.1 - 1.6) × 10−3 mm2/s]; P = 0.005). CT histogram analysis showed that NEC were more heterogeneous on portal venous phase images (Entropy-0: 4.7 ± 0.2 [SD] [range: 4.2-5.1] vs. 4.5 ± 0.4 [SD] [range: 3.7-4.9]; P = 0.023).ConclusionPancreatic NECs are larger, more frequently hypoattenuating and more heterogeneous with hemorrhagic content than G3-NET on CT and MRI. 相似文献
30.
《Diagnostic and interventional imaging》2020,101(9):555-564
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%. 相似文献