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   23471篇
  免费   1857篇
  国内免费   863篇
耳鼻咽喉   114篇
儿科学   627篇
妇产科学   224篇
基础医学   1808篇
口腔科学   532篇
临床医学   1902篇
内科学   2297篇
皮肤病学   353篇
神经病学   1611篇
特种医学   806篇
外国民族医学   6篇
外科学   1399篇
综合类   3146篇
现状与发展   3篇
一般理论   3篇
预防医学   2660篇
眼科学   422篇
药学   4822篇
  19篇
中国医学   1686篇
肿瘤学   1751篇
  2024年   74篇
  2023年   318篇
  2022年   534篇
  2021年   727篇
  2020年   781篇
  2019年   702篇
  2018年   686篇
  2017年   831篇
  2016年   879篇
  2015年   825篇
  2014年   1474篇
  2013年   2119篇
  2012年   1286篇
  2011年   1292篇
  2010年   1018篇
  2009年   1054篇
  2008年   1048篇
  2007年   1074篇
  2006年   955篇
  2005年   873篇
  2004年   727篇
  2003年   710篇
  2002年   559篇
  2001年   465篇
  2000年   377篇
  1999年   321篇
  1998年   323篇
  1997年   322篇
  1996年   272篇
  1995年   324篇
  1994年   253篇
  1993年   222篇
  1992年   240篇
  1991年   223篇
  1990年   210篇
  1989年   192篇
  1988年   193篇
  1987年   193篇
  1986年   164篇
  1985年   188篇
  1984年   199篇
  1983年   111篇
  1982年   164篇
  1981年   106篇
  1980年   116篇
  1979年   103篇
  1978年   70篇
  1977年   81篇
  1976年   63篇
  1975年   44篇
排序方式: 共有10000条查询结果,搜索用时 328 毫秒
1.
目的 观察结肠癌HCT116细胞健脾消癌方的条件培养液对HUVEC细胞管腔形成的影响,从PI3K/Akt生物轴调控角度探讨其作用机制。方法 培养HCT116细胞,细胞设3组:对照组,健脾消癌方组(加入15%健脾消癌方含药血清)及人参皂苷Rg3组;制备HCT116细胞健脾消癌方条件培养液(分组及制备方法见实验方法),用条件培养液干预HUVEC(脐静脉内皮细胞,Human Umbilical Vein Endothelial Cells),Matrigel基质胶法检测HCT116细胞健脾消癌方条件培养液对HUVEC小管形成的影响。随后采用蛋白免疫印迹法(Western blot)检测各组HCT116细胞磷脂酰肌醇3-激酶(PI3K)、蛋白激酶B(Akt)、p-Akt、VEGF(血管内皮生长因子,Vascular endothelial growth factor)蛋白表达。最后在结肠癌HCT116荷瘤小鼠中验证健脾消癌方对肿瘤生长速度的影响,并经瘤组织VEGF蛋白表达、CD31免疫组化染色检测肿瘤内血管生成情况。结果 模型组HUVEC细胞管腔形成较空白血清组显著增加(P<0.05);健脾消癌方组及人参皂苷Rg3组较模型组HUVEC细胞管腔形成显著减少(P<0.01)。p-Akt和VEGF蛋白表达水平模型组高于空白血清组(P<0.05),健脾消癌方组及人参皂苷Rg3组显著低于模型组(P<0.01);PI3K、Akt蛋白表达量组间差异无统计学意义。与对照组比较,模型组荷瘤小鼠肿瘤体积显著性增大,瘤组织内VEGF表达、CD31阳性面积显著性增加,差异有统计学意义(P<0.05);与模型组比较,健脾消癌方组及人参皂苷Rg3组荷瘤小鼠肿瘤体积显著减小,瘤组织内VEGF表达、CD31阳性面积降低,差异有统计学意义(P<0.05)。结论 健脾消癌方可抑制肿瘤的血管生成和生长,其作用机制可能与PI3K/Akt生物轴调控VEGF表达有关。  相似文献   
2.
3.
《Vaccine》2022,40(11):1594-1605
In addition to providing pathogen-specific immunity, vaccines can also confer nonspecific effects (NSEs) on mortality and morbidity unrelated to the targeted disease. Immunisation with live vaccines, such as the BCG vaccine, has generally been associated with significantly reduced all-cause infant mortality. In contrast, some inactivated vaccines, such as the diphtheria, tetanus, whole-cell pertussis (DTPw) vaccine, have been controversially associated with increased all-cause mortality especially in female infants in high-mortality settings. The NSEs associated with BCG have been attributed, in part, to the induction of trained immunity, an epigenetic and metabolic reprograming of innate immune cells, increasing their responsiveness to subsequent microbial encounters. Whether non-live vaccines such as DTPw induce trained immunity is currently poorly understood. Here, we report that immunisation of mice with DTPw induced a unique program of trained immunity in comparison to BCG immunised mice. Altered monocyte and DC cytokine responses were evident in DTPw immunised mice even months after vaccination. Furthermore, splenic cDCs from DTPw immunised mice had altered chromatin accessibility at loci involved in immunity and metabolism, suggesting that these changes were epigenetically mediated. Interestingly, changing the order in which the BCG and DTPw vaccines were co-administered to mice altered subsequent trained immune responses. Given these differences in trained immunity, we also assessed whether administration of these vaccines altered susceptibility to sepsis in two different mouse models. Immunisation with either BCG or a DTPw-containing vaccine prior to the induction of sepsis did not significantly alter survival. Further studies are now needed to more fully investigate the potential consequences of DTPw induced trained immunity in different contexts and to assess whether other non-live vaccines also induce similar changes.  相似文献   
4.
The present narrative review examines the scientific evidence of the biological mechanisms that may link periodontitis and diabetes, as a source of comorbidity. Publications regarding periodontitis and diabetes, in human, animals, and in vitro were screened for their relevance. Periodontal microbiome studies indicate a possible association between altered glucose metabolism in prediabetes and diabetes and changes in the periodontal microbiome. Coinciding with this, hyperglycemia enhances expression of pathogen receptors, which enhance host response to the dysbiotic microbiome. Hyperglycemia also promotes pro-inflammatory response independently or via the advanced glycation end product/receptor for advanced glycation end product pathway. These processes excite cellular tissue destruction functions, which further enhance pro-inflammatory cytokines expression and alteration in the RANKL/osteoprotegerin ratio, promoting formation and activation of osteoclasts. The evidence supports the role of several pathogenic mechanisms in the path of true causal comorbidity between poorly controlled diabetes and periodontitis. However, further research is needed to better understand these mechanisms and to explore other mechanisms.  相似文献   
5.
The progress of modern medicine would be impossible without the use of general anesthetics (GAs). Despite advancements in refining anesthesia approaches, the effects of GAs are not fully reversible upon GA withdrawal. Neurocognitive deficiencies attributed to GA exposure may persist in neonates or endure for weeks to years in the elderly. Human studies on the mechanisms of the long-term adverse effects of GAs are needed to improve the safety of general anesthesia but they are hampered not only by ethical limitations specific to human research, but also by a lack of specific biological markers that can be used in human studies to safely and objectively study such effects. The latter can primarily be attributed to an insufficient understanding of the full range of the biological effects induced by GAs and the molecular mechanisms mediating such effects even in rodents, which are far more extensively studied than any other species. Our most recent experimental findings in rodents suggest that GAs may adversely affect many more people than is currently anticipated. Specifically, we have shown that anesthesia with the commonly used GA sevoflurane induces in exposed animals not only neuroendocrine abnormalities (somatic effects), but also epigenetic reprogramming of germ cells (germ cell effects). The latter may pass the neurobehavioral effects of parental sevoflurane exposure to the offspring, who may be affected even at levels of anesthesia that are not harmful to the exposed parents. The large number of patients who require general anesthesia, the even larger number of their future unexposed offspring whose health may be affected, and a growing number of neurodevelopmental disorders of unknown etiology underscore the translational importance of investigating the intergenerational effects of GAs. In this mini review, we discuss emerging experimental findings on neuroendocrine, epigenetic, and intergenerational effects of GAs.  相似文献   
6.
骨碎补是历代临床常用中药,具有疗伤止痛、补肾强骨、消风祛斑等功效。其主要含黄酮、苯丙素、三萜、酚酸及其苷等类化学成分,现代研究表明骨碎补具有抗骨质疏松、促进骨折愈合、促软骨再生、护牙健齿、保护肾功能、抗炎、防治中毒性耳聋、降血脂等多种生物活性,开发前景广阔。本文对近年来骨碎补的化学成分、药理作用及临床应用研究进行综述,以期为骨碎补的进一步深入系统的研究和开发利用提供依据。  相似文献   
7.
This study explored the relationship between active mediation, exposure to Daniel Tiger’s Neighborhood, and key indicators of preschoolers’ social and emotional development. One hundred and twenty-seven children aged 2–6 either watched or did not watch 10 episodes of Daniel Tiger’s Neighborhood over a two-week period. Results revealed that preschoolers who watched the program exhibited higher levels of empathy, self-efficacy, and emotion recognition when their regular TV-watching experiences are frequently accompanied by active mediation. This was especially true for younger preschoolers and preschoolers from low-income families. Implications for policy-makers, parents, producers of prosocial programming, and educators are discussed.  相似文献   
8.
舌癌患者手术及放化疗后会出现构音障碍、吞咽困难、口腔黏膜炎、口干、营养不良等并发症,使患者生存质量下降,甚至导致肿瘤的复发转移,影响生存期,单一方法往往顾此失彼。依托于中国中医科学院西苑医院肿瘤康复基地,杨宇飞教授在国内外调研考察基础上,结合中国国情,构建了一种“门诊多学科肿瘤康复模式”,在舌癌康复方面,以患者为中心,以中医肿瘤内科为主导,多学科共同参与,结合康复科、口腔科、营养科、药剂科等各科优势,形成全程个体化规范序贯康复方案,对患者及早进行康复,在放疗前进行预防性干预尤其重要,使患者能够快速缓解手术和放疗的不良反应,患者获益明显。现取两个典型案例总结其舌癌多学科康复的经验,以期为舌癌的康复提供借鉴。  相似文献   
9.

Objective

To examine the experience of interracial anxiety among health professionals and how it may affect the quality of their interactions with patients from racially marginalized populations. We explored the influence of prior interracial exposure—specifically through childhood neighborhoods, college student bodies, and friend groups—on interracial anxiety among medical students and residents. We also examined whether levels of interracial anxiety change from medical school through residency.

Data Source

Web-based longitudinal survey data from the Medical Student Cognitive Habits and Growth Evaluation Study.

Study Design

We used a retrospective longitudinal design with four observations for each trainee. The study population consisted of non-Black US medical trainees surveyed in their 1st and 4th years of medical school and 2nd and 3rd years of residency. Mixed effects longitudinal models were used to assess predictors of interracial anxiety and assess changes in interracial anxiety scores over time.

Principal Findings

In total, 3155 non-Black medical trainees were followed for 7 years. Seventy-eight percent grew up in predominantly White neighborhoods. Living in predominantly White neighborhoods and having less racially diverse friends were associated with higher levels of interracial anxiety among medical trainees. Trainees' interracial anxiety scores did not substantially change over time; interracial anxiety was highest in the 1st year of medical school, lowest in the 4th year, and increased slightly during residency.

Conclusions

Neighborhood and friend group composition had independent effects on interracial anxiety, indicating that premedical racial socialization may affect medical trainees' preparedness to interact effectively with diverse patient populations. Additionally, the lack of substantial change in interracial anxiety throughout medical training suggests the importance of providing curricular tools and structure (e.g., instituting interracial cooperative learning activities) to foster the development of healthy interracial relationships.  相似文献   
10.
目的:探讨中西医结合护理干预妊娠晚期合并急性单纯性阑尾炎的临床疗效。方法:将2017 年9 月—2018 年12月于我院接受中西医结合保守治疗的31 例妊娠晚期合并急性单纯性阑尾炎患者作为研究对象,按随机数表法随机分为中西医结合护理组(观察组16 例)与常规护理组(对照组15 例),对照组采取常规护理措施,观察组在对照组的基础上增加中西医结合护理措施,对比两组患者的临床疗效。结果:观察组患者的心理状态变化、新生儿体质状况以及临床疗效等指标等情况均明显优于对照组,且组间对比差异显著有统计学意义(P < 0.05)。结论:中西医结合护理对妊娠晚期合并急性单纯性阑尾炎有较好的临床效果,可减少、甚至避免孕妇因合并急性阑尾炎而造成的打击和创伤。  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