全文获取类型
收费全文 | 11429篇 |
免费 | 1021篇 |
国内免费 | 544篇 |
专业分类
耳鼻咽喉 | 95篇 |
儿科学 | 132篇 |
妇产科学 | 177篇 |
基础医学 | 1218篇 |
口腔科学 | 169篇 |
临床医学 | 1392篇 |
内科学 | 1607篇 |
皮肤病学 | 139篇 |
神经病学 | 572篇 |
特种医学 | 530篇 |
外国民族医学 | 12篇 |
外科学 | 1337篇 |
综合类 | 2018篇 |
现状与发展 | 7篇 |
一般理论 | 2篇 |
预防医学 | 643篇 |
眼科学 | 178篇 |
药学 | 1175篇 |
8篇 | |
中国医学 | 736篇 |
肿瘤学 | 847篇 |
出版年
2024年 | 48篇 |
2023年 | 158篇 |
2022年 | 409篇 |
2021年 | 502篇 |
2020年 | 420篇 |
2019年 | 305篇 |
2018年 | 369篇 |
2017年 | 386篇 |
2016年 | 341篇 |
2015年 | 487篇 |
2014年 | 684篇 |
2013年 | 571篇 |
2012年 | 833篇 |
2011年 | 873篇 |
2010年 | 545篇 |
2009年 | 492篇 |
2008年 | 613篇 |
2007年 | 572篇 |
2006年 | 533篇 |
2005年 | 551篇 |
2004年 | 367篇 |
2003年 | 381篇 |
2002年 | 417篇 |
2001年 | 277篇 |
2000年 | 325篇 |
1999年 | 336篇 |
1998年 | 196篇 |
1997年 | 168篇 |
1996年 | 135篇 |
1995年 | 133篇 |
1994年 | 88篇 |
1993年 | 69篇 |
1992年 | 61篇 |
1991年 | 57篇 |
1990年 | 55篇 |
1989年 | 42篇 |
1988年 | 32篇 |
1987年 | 32篇 |
1986年 | 29篇 |
1985年 | 18篇 |
1984年 | 16篇 |
1983年 | 11篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 10篇 |
1972年 | 4篇 |
1971年 | 3篇 |
1970年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
172.
顶空气相色谱法测定盐酸依匹斯汀中溶剂残留 总被引:26,自引:3,他引:26
建立顶空气相色谱法分析盐酸依匹斯汀中溶剂残留.采用DB-1大口径毛细管柱,以正丙醇为内标进行定量.甲醇、乙醚、三氯甲烷、四氢呋喃的线性范围分别为7.9 ~ 317.0μg·ml-1 (r=0.9996),0.7~35.5μg·ml-1(r=0.9998),1.5~73.5μg·ml-1 (r=0.9992),0.9~44.4μg·ml-1(r=0.9994),回收率分别为101.64%,97.18%,99.32%,101.12%,RSD分别为1.97%,1.10%,2.40%,0.84%.本方法简单、准确、灵敏度高、重现性好. 相似文献
173.
174.
175.
Dongping Chen Zhaobing Su Linsheng Weng Longbin Cao Can Chen Sufen Zeng 《Journal of biomaterials science. Polymer edition》2013,24(15):1909-1919
AbstractAs a promising candidate, biodegradable Poly-L-lactic Acid (PLLA) has been extensively used in coronary artery stents. In our previous reports, PLLA stents implanted in porcine coronary arteries showed safety without stent thrombosis. However, inflammatory responses were observed, which needed further study. In this study, human aortic endothelial cells (HAEC) were treated with different volume percentages of extract of pre-degraded PLLA (extract of PLLA) in vitro, and the cell growth curve and morphological changes were examined. The expression of inflammatory cytokines such as NF-κB, VEGF and VCAM-1 were also observed by ELISA. In addition, PLLA stent was implanted in porcine coronary artery to examine morphological changes, functional marker eNOS and inflammatory responses. The extract of PLLA caused significant growth inhibition and release of NF-κB, VEGF and VCAM-1 in HAEC with volume percentage-dependence. Although re-endothelialization and expression of eNOS was observed, expression of NF-κB and lymphocytes surrounding PLLA were also found after PLLA stents were implanted in the artery. This study demonstrated the effects of inflammation on endothelial cells induced by PLLA degradation in vitro and showed the inflammation in vivo, suggesting that anti-inflammatory strategy is necessary for PLLA stent implantation in the artery. 相似文献
176.
177.
Cajal间质细胞(interstitial cells of Cajal,ICC)是一类主要分布于胃肠道的间质细胞,是胃肠道的起搏细胞(pacemaker cell)和信号传导细胞,与肌细胞以及末梢神经元有着紧密的关系,具有激发和促进胃肠蠕动的作用.借助于电子显微镜技术,清楚观察到了ICC位置分布和内部精细结构;应用免疫荧光等生化技术,发现了其特殊表达的C-kit蛋白;利用电生理技术,得知多种胃肠动力障碍疾病也与其异常有关.多年来,学者逐渐在胃肠道、胆道、膀胱、子宫等部位发现了ICC的踪迹,并试图阐述其与某些疾病的发生机制.本文就ICC的起源、形态学、受体和功能、以及与其相关的疾病等作一综述. 相似文献
178.
Junjie Zhao Xuhong Fu Hao Chen Lingqiang Min Jie Sun Jingyi Yin Jianping Guo Haojie Li Zhaoqing Tang Yuanyuan Ruan Xuefei Wang Yihong Sun Liyu Huang 《British journal of cancer》2021,124(2):425
BACKGROUND A large proportion of gastric cancer patients are susceptible to chemoresistance, while the underlying mechanism remains obscure. Stress granules (SGs) play a self-defence role for tumour cells in inhibiting chemotherapy-induced apoptosis. As an SG assembly effector, G3BP1 (Ras-GTPase-activating protein SH3 domain-binding protein) has been reported to be overexpressed in gastric cancer; thus, here we aim to explore its potent roles in gastric cancer chemoresistance.METHODS Kaplan–Meier analysis was used to compare survival rates in gastric cancer patients with different G3BP1 expression. The influence of G3BP1 on gastric cancer cell chemoresistance and apoptosis were evaluated by in vitro and in vivo approaches. The interaction between G3BP1 and YWHAZ was assessed by immunohistochemistry, immunoprecipitation and immunofluorescence.RESULTS G3BP1 was associated with the poor outcome of gastric cancer patients who received adjuvant chemotherapy. G3BP1 knockdown significantly increased the sensitivity of gastric cancer cells to chemotherapy drugs. Mechanically, cell apoptosis and pro-apoptotic-associated molecules were significantly elevated upon G3BP1 depletion. Gene co-expression network analyses identified YWHAZ as the critical interlayer of G3BP1; as a result, G3BP1 interacted with YWHAZ to sequester Bax into the cytoplasm. Clinically, G3BP1highYWHAZhigh gastric cancer patients displayed the worst outcome compared with other patients after chemotherapy.CONCLUSIONS The expression of G3BP1 and YWHAZ could predict the adjuvant chemotherapy benefit in gastric cancer patients.Subject terms: Gastric cancer, Cell death 相似文献
179.
Jae Hyun Kim Casey N Ta Cong Liu Cynthia Sung Alex M Butler Latoya A Stewart Lyudmila Ena James R Rogers Junghwan Lee Anna Ostropolets Patrick B Ryan Hao Liu Shing M Lee Mitchell S V Elkind Chunhua Weng 《J Am Med Inform Assoc》2021,28(1):14
ObjectiveThis research aims to evaluate the impact of eligibility criteria on recruitment and observable clinical outcomes of COVID-19 clinical trials using electronic health record (EHR) data.Materials and MethodsOn June 18, 2020, we identified frequently used eligibility criteria from all the interventional COVID-19 trials in ClinicalTrials.gov (n = 288), including age, pregnancy, oxygen saturation, alanine/aspartate aminotransferase, platelets, and estimated glomerular filtration rate. We applied the frequently used criteria to the EHR data of COVID-19 patients in Columbia University Irving Medical Center (CUIMC) (March 2020–June 2020) and evaluated their impact on patient accrual and the occurrence of a composite endpoint of mechanical ventilation, tracheostomy, and in-hospital death.ResultsThere were 3251 patients diagnosed with COVID-19 from the CUIMC EHR included in the analysis. The median follow-up period was 10 days (interquartile range 4–28 days). The composite events occurred in 18.1% (n = 587) of the COVID-19 cohort during the follow-up. In a hypothetical trial with common eligibility criteria, 33.6% (690/2051) were eligible among patients with evaluable data and 22.2% (153/690) had the composite event.DiscussionBy adjusting the thresholds of common eligibility criteria based on the characteristics of COVID-19 patients, we could observe more composite events from fewer patients.ConclusionsThis research demonstrated the potential of using the EHR data of COVID-19 patients to inform the selection of eligibility criteria and their thresholds, supporting data-driven optimization of participant selection towards improved statistical power of COVID-19 trials. 相似文献