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   75917篇
  免费   6649篇
  国内免费   5043篇
耳鼻咽喉   636篇
儿科学   905篇
妇产科学   836篇
基础医学   6833篇
口腔科学   1479篇
临床医学   10614篇
内科学   9352篇
皮肤病学   869篇
神经病学   2694篇
特种医学   2454篇
外国民族医学   30篇
外科学   6527篇
综合类   16632篇
现状与发展   23篇
一般理论   4篇
预防医学   6877篇
眼科学   1495篇
药学   8707篇
  95篇
中国医学   5446篇
肿瘤学   5101篇
  2024年   232篇
  2023年   814篇
  2022年   2208篇
  2021年   2816篇
  2020年   2279篇
  2019年   1863篇
  2018年   1884篇
  2017年   2091篇
  2016年   1802篇
  2015年   3088篇
  2014年   3986篇
  2013年   4037篇
  2012年   6263篇
  2011年   6707篇
  2010年   5314篇
  2009年   4895篇
  2008年   5254篇
  2007年   5228篇
  2006年   4931篇
  2005年   4383篇
  2004年   3132篇
  2003年   2846篇
  2002年   2360篇
  2001年   1781篇
  2000年   1534篇
  1999年   1274篇
  1998年   773篇
  1997年   753篇
  1996年   550篇
  1995年   495篇
  1994年   442篇
  1993年   272篇
  1992年   259篇
  1991年   190篇
  1990年   172篇
  1989年   131篇
  1988年   113篇
  1987年   126篇
  1986年   85篇
  1985年   75篇
  1984年   32篇
  1983年   22篇
  1982年   12篇
  1981年   14篇
  1980年   9篇
  1979年   12篇
  1978年   5篇
  1974年   6篇
  1964年   4篇
  1931年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Cao  Jie  Xie  Chengyu  Hou  Zhiru 《Ecotoxicology (London, England)》2022,31(2):259-270
Ecotoxicology - Soil heavy metal pollution evaluations are a necessary measure for mine ecological control projects. In this study, the heavy metals Pb, Zn and Cd were studied in mining areas,...  相似文献   
2.
Clinical and Experimental Medicine - Colon cancer is one of most common cancers. The progression of various cancers is driven by miRNA-570. The role of miRNA-570 in the progression of colon cancer...  相似文献   
3.
Zedoary tumeric (Curcumae Rhizoma, Ezhu in Chinese) has a long history of application and has great potential in the treatment of liver cancer. The anti liver cancer effect of zedoary tumeric depends on the combined action of multiple pharmacodynamic substances. In order to clarify the specific mechanism of zedoary tumeric against liver cancer, this paper first analyzes the mechanism of its single pharmacodynamic substance against liver cancer, and then verifies the joint anti liver cancer mechanism of its "pharmacodynamic group". By searching the research on the anti hepatoma effect of active components of zedoary tumeric in recent years, we found that pharmacodynamic substances, including curcumol, zedoarondiol, curcumenol, curzerenone, curdione, curcumin, germacrone, β-elemene, can act on multi-target and multi-channel to play an anti hepatoma role. For example, curcumin can regulate miR, GLO1, CD133, VEGF, YAP, LIN28B, GPR81, HCAR-1, P53 and PI3K/Akt/mTOR, HSP70/TLR4 and NF-κB. Wnt/TGF/EMT, Nrf2/Keap1, JAK/STAT and other pathways play an anti hepatoma role. Network pharmacological analysis showed that the core targets of the "pharmacodynamic group" for anti-life cancer are AKT1, EGFR, MAPK8, etc, and the core pathways are neuroactive live receiver interaction, nitrogen metabolism, HIF-1 signaling pathway, etc. At the same time, by comparing and analyzing the relationship between the specific mechanisms of pharmacodynamic substance and "pharmacodynamic group", it is found that they have great reference significance in target, pathway, biological function, determination of core pharmacodynamic components, formation of core target protein interaction, in-depth research of single pharmacodynamic substance, increasing curative effect and so on. By analyzing the internal mechanism of zedoary tumeric pharmacodynamic substance and "pharmacodynamic group" in the treatment of liver cancer, this paper intends to provide some ideas and references for the deeper pharmacological research of zedoary tumeric and the relationship between pharmacodynamic substance and "pharmacodynamic group".  相似文献   
4.
5.
Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T2-mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T2-mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T2-maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T2 relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T2 was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T2 relaxation time was derived (R2 = 0.98): T2 (ms) = 30.45 – 1.05 × FP. Thus, these results demonstrate a statistical agreement between T2-map–quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T2-mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.  相似文献   
6.
BackgroundComminuted patellar fractures are not rare, and the ideal treatment method remains controversial. The present study was conducted to evaluate effects and compare complications of two different methods used to treat comminuted patellar fractures.MethodsFrom March 2010 to August 2016, 102 cases of 34-C2 or 34-C3 comminuted patellar fractures were treated at our hospital, wherein patients received two different treatments: titanium cable tension band with cerclage method (group A) and intrafragmentary screws with X-shaped plating technique (group B). At follow-ups, articular step-off, range of motion (ROM), Lysholm scores, time of union, and complications were recorded and analyzed. Radiographic and clinical data as well as rate of complications were statistically analyzed.ResultsIn total, 87 patients were included in the final analysis (n = 47 in group A and n = 40 in group B). No significant differences were noted in terms of cost of implant, age, gender, rate of 34-C3 fractures, rate of layered inferior pole fractures, postoperative articular step-off and union time. At 2-year follow-up, average Lysholm scores, ROM and rate of complications were (89.0 ± 4.5), (122°±12°) and (27.7%) in group A and (90.2 ± 3.9), (124°±11°) and (17.5%) in group B, respectively, with no significant differences (p > 0.05). The mean time of surgery in group B was shorter than that in group A with significant difference (p < 0.05).ConclusionsTreatment using the intrafragmentary screws and plate method for amenable comminuted patellar fractures achieved similar complication rate and favorable functional outcomes at the 2-year follow-up, which was comparable to the titanium cable tension band with cerclage method. Thus, the intrafragmentary screws and plate method is effective, safe and convenient for 34-C2/C3 comminuted patellar fractures, especially appropriate for patients with layered fragments.  相似文献   
7.
目的 运用网络药理学方法及分子对接技术探讨黄芪干预腹膜纤维化的可能机制。方法 利用中药系统药理学数据库及分析平台(TCMSP)检索黄芪的主要化学成分及靶点,并补充文献报道相关药理作用的成分作为潜在活性成分。以"peritoneal fibrosis"为关键词分别在OMIM、Genecards获取目前已知的与腹膜纤维化相关的疾病靶点,后取两者的交集靶点;对交集基因通过STRING数据库与Cytoscape 3.7.2软件构建"药物-成分-靶点-疾病"网络及蛋白互作(PPI)网络并筛选核心网络。基于R软件使用Bioconductor生物信息软件对核心靶点进行GO及KEGG富集分析,最终采用AutoDock软件将主要有效成分与核心靶点进行分子对接,得出其结合能力。结果 筛选出20个黄芪活性成分及文献报道有相关药理作用4个, 457药物作用靶点,与674个腹膜纤维化病靶点取交集,得到86个共同靶点。GO功能富集分析提示黄芪拮抗腹膜纤维化主要参与了蛋白激酶B信号转导的调节、细胞对化学的应激反应、炎症反应的调节等通路; KEGG通路富集分析主要涉及调控肿瘤、磷脂酰肌醇-3-羟激酶-蛋白激酶B(PI3K-Akt)、晚期糖基化终末产物/晚期糖基化终末产物受体(AGE-RAGE)、人类巨细胞病毒感染、HIF-1信号通路等;分子对接结果显示关键靶点与活性成分具有较好的结合能力。结论 黄芪治疗腹膜纤维化的分子机制,可能与抑制炎症及氧化应激反应、调节多种信号通路等相关。  相似文献   
8.
目的:观察应力刺激结合温经活血汤治疗骨折延迟愈合的临床疗效。方法:40例随机分成两组各20例,两组均行应力刺激。治疗组给予温经活血汤治疗、对照组给予接骨七厘片治疗。结果:治疗4周、8周两组血清ALP、BGP指标比较差异有统计学意义(P<0.05),治疗4周、8周和治疗结束后4周骨痂评分两组比较差异均有统计学意义(P<0.05),总体疗效治疗组优于对照组(P<0.05)。结论:应力刺激结合温经活血汤治疗骨折延迟愈合疗效较好。  相似文献   
9.
10.
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