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   120415篇
  免费   11600篇
  国内免费   6069篇
耳鼻咽喉   860篇
儿科学   1094篇
妇产科学   1607篇
基础医学   29768篇
口腔科学   3467篇
临床医学   8331篇
内科学   15580篇
皮肤病学   2138篇
神经病学   7796篇
特种医学   2383篇
外国民族医学   301篇
外科学   9930篇
综合类   20081篇
现状与发展   23篇
一般理论   2篇
预防医学   4682篇
眼科学   2836篇
药学   12828篇
  14篇
中国医学   4943篇
肿瘤学   9420篇
  2024年   47篇
  2023年   1179篇
  2022年   1674篇
  2021年   3176篇
  2020年   3191篇
  2019年   2887篇
  2018年   3104篇
  2017年   3453篇
  2016年   3966篇
  2015年   4458篇
  2014年   10398篇
  2013年   10806篇
  2012年   8384篇
  2011年   9047篇
  2010年   9099篇
  2009年   8531篇
  2008年   7061篇
  2007年   6080篇
  2006年   5547篇
  2005年   4749篇
  2004年   4019篇
  2003年   3282篇
  2002年   2506篇
  2001年   2139篇
  2000年   1825篇
  1999年   1522篇
  1998年   1310篇
  1997年   1239篇
  1996年   1116篇
  1995年   1339篇
  1994年   1191篇
  1993年   1046篇
  1992年   858篇
  1991年   798篇
  1990年   682篇
  1989年   686篇
  1988年   577篇
  1987年   532篇
  1986年   458篇
  1985年   694篇
  1984年   627篇
  1983年   433篇
  1982年   535篇
  1981年   416篇
  1980年   346篇
  1979年   304篇
  1978年   211篇
  1977年   161篇
  1976年   148篇
  1975年   63篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Objective: To investigate the effects of matrine on antigen presentation of dendritic cells (DCs), and to explore the pharmacological mechanism of matrine on anti-tumor effect. Methods: Different concentrations (0, 1, 2, 4, 8 and 16 μ g/mL) of matrine were co-cultured with DCs, the harvested DCs were co-cultured with antigens of Lewis lung cancer (LLC) cells, and then DCs and T cells were co-cultured to produce DCs-activated killer (DAK) cells, which have significant tumor-killing activity. The expression of cytokines, mRNA and protein of toll-like receptors (TLRs) in DCs were detected by enzyme linked immunosobent assay, polymerase chain reaction and Western blot, respectively. And the killing effect of DAK were measured by MTT assay. Results: Matrine significantly increased the mRNA expression of TLR7, TLR8, myeloid differentiation factor 88 (MyD88), tumor necrosis factor receptor-associated factor 6 (TRAF-6) and Iκ B kinase (IKK), as well as the protein expression of TLR7 and TLR8, and up-regulated the levels of interleukin-12 (IL-12), IL-6 and tumor necrosis factor-α (TNF-α ), meanwhile, it also increased the expressions of MHC-Ⅱ , CD54, CD80 and CD86 in DCs. DCs-activated effector T cells had significant tumor-killing activity. When the concentration of matrine was more than 4 μ g/mL, all indices had significant difference (P<0.01 or P<0.05). Conclusion: Matrine plays an anti-tumor role by regulating TLRs signal transduction pathway, promoting the secretion of inflammatory cytokines and enhancing immune function.  相似文献   
102.
王盼  王芝涛 《安徽医学》2021,42(8):840-842
目的 探讨单核细胞型髓系来源抑制性细胞(M-MDSC)在非霍奇金淋巴瘤(NHL)患者中的表达水平以及临床意义.方法 选取2017年9月至2020年1月解放军第九○一医院和安徽医科大学第二附属医院35例初诊NHL患者作为试验组,同期选取20例健康志愿者作为对照组.比较两组研究对象M-MDSC、精氨酸酶-1(Arg-1)mRNA及诱导型一氧化氮合酶(iN-OS)mRNA的表达水平.分析M-MDSC与NHL患者年龄、性别、临床分期、病理分型、乳酸脱氢酶(LDH)以及IPI评分等临床指标的相关性.结果 试验组患者M-MDSC表达水平为(32.64±11.23)%,高于对照组,差异有统计学意义(P<0.05).Ⅲ~Ⅳ期、LDH升高及IPI评分为3~5分的NHL患者,M-MDSC水平升高,差异有统计学意义(P<0.05).试验组患者Arg-1水平为(18.12±5.25)ng/mL,iNOS mRNA相对水平为(12.36±3.68),均高于对照组,差异有统计学意义(P<0.05).结论 M-MDSC参与NHL患者发病过程,与疾病进展密切相关,可能成为治疗NHL的新靶点.  相似文献   
103.
Dental pulp stem cells (DPSCs) have emerged as a promising tool with great potential for use in tissue regeneration and engineering. Some of the main advantages of these cells are their multifaceted differentiation capacity, along with their high proliferation rate, a relative simplicity of extraction and culture that enables obtaining patient-specific cell lines for their use in autologous cell therapy. PubMed, Scopus and Google Scholar databases were searched for relevant articles related to the use of DPSCs in regeneration of dentin-pulp complex (DPC), periodontal tissues, salivary gland and craniomaxillofacial bone defects. Few studies were found regarding the use of DPSCs for regeneration of DPC. Scaffold-based combined with DPSCs isolated from healthy pulps was the strategy used for DPC regeneration. Studies involved subcutaneous implantation of scaffolds loaded with DPSCs pretreated with odontogenic media, or performed on human tooth root model as a root slice. Most of the studies were related to periodontal tissue regeneration which mainly utilized DPSCs/secretome. For periodontal tissues, DPSCs or their secretome were isolated from healthy or inflamed pulps and they were used either for preclinical or clinical studies. Regarding salivary gland regeneration, the submandibular gland was the only model used for the preclinical studies and DPSCs or their secretome were isolated only from healthy pulps and they were used in preclinical studies. Likewise, DPSCs have been studied for craniomaxillofacial bone defects in the form of mandibular, calvarial and craniofacial bone defects where DPSCs were isolated only from healthy pulps for preclinical and clinical studies. From the previous results, we can conclude that DPSCs is promising candidate for dental and oral tissue regeneration.  相似文献   
104.
嵌合抗原受体T细胞(CAR-T)和新型靶向治疗等生物免疫疗法的临床应用开辟了多发性骨髓瘤(MM)治疗的新领域。靶向B细胞成熟抗原(BCMA)、同种异体CAR-T、抗体偶联药物(ADC)及靶向BCMA的双特异性抗体在多项临床研究中获得了令人瞩目的疗效及较好的安全性。文章结合第62届美国血液学会(ASH)年会的相关报道对MM免疫治疗进展进行介绍。  相似文献   
105.
Novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a global pandemic. SARS-CoV-2 is an RNA virus and has a glycosylated spike (S) protein used for genome encoding. COVID-19 can lead to a cytokine storm and patients usually have early respiratory signs and further secondary infections, which can be fatal. COVID-19 has entered an emergency phase, but there are still no specific effective drugs for this disease. Mesenchymal stem cells (MSCs) are multipotent stromal cells, which cause antiapoptosis and can repair damaged epithelial cells. Many clinical trials have proved that MSC therapy could be a potential feasible therapy for COVID-19 patients, especially those with acute respiratory distress syndrome, without serious adverse events or toxicities. However, more studies are needed in the future, in order to confirm the effect of this therapy.  相似文献   
106.
Objective To explore the mechanism of Pi(Spleen)-deficiency-induced functional diarrhea(FD)model rats treated by Shenling Baizhu Powder(参苓白术散,SBP).Methods Thirty male Sprague-Dawley rats were randomly divided into 5 groups including control,model,low-,medium-,and high-dose SBP groups(SBPLDG,SBPMDG,SBPHDG),6 rats in each group,respectively.Pi-deficiency-induced FD rats model was developed through Radix et Rhizoma Rhei gavage for 7 days.After modeling,the rats were treated with 3 doses of SBP[0.93,1.86,and 3.72 g/(kg·d)],and the rats in the control and model groups were given pure water for 7 days.The diarrhea index was calculated.On the 7th and 14th days,the traveled distance of rat was measured by the open field test.Serum D-xylose content was determined by the phloroglucinol method and interleukin(IL)-10 and IL-17 levels were measured using an enzyme-linked immunosorbent assay kit.The content of Treg cells was determined by flow cytometry.Results Compared with the control group,the diarrhea index and IL-17 level in the model group were significantly higher and the total exercise distance and D-xylose content significantly decreased(P>0.05).The expression of IL-10 in the SBPHDG group was significantly up-regulated,and serum D-xylose level and Treg cells increased significantly compared with the model group(P>0.05).Conclusion High-dose SBP exhibited ameliorating effects against Pi-deficiency induced FD,which might be attributed to its modulations on intestinal absorption function as well as adaptive immunity in mesenteric lymph nodes of rat.  相似文献   
107.
《Vaccine》2021,39(19):2668-2675
Relapsing malaria caused by Plasmodium vivax is a neglected tropical disease and an important cause of malaria worldwide. Vaccines to prevent clinical disease and mosquito transmission of vivax malaria are needed to overcome the distinct challenges of this important public health problem. In this vaccine immunogenicity study in mice, we examined key variables of responses to a P. vivax Duffy binding protein vaccine, a leading candidate to prevent the disease-causing blood-stages. Significant sex-dependent differences were observed in B cell (CD80+) and T cell (CD8+) central memory subsets, resulting in significant differences in functional immunogenicity and durability of anti-DBP protective efficacy. These significant sex-dependent differences in inbred mice were in the CD73+CD80+ memory B cell, H2KhiCD38hi/lo, and effector memory subsets. This study highlights sex and immune genes as critical variables that can impact host responses to P. vivax antigens and must be taken into consideration when designing clinical vaccine studies.  相似文献   
108.
Introduction: The sciatic nerve is one of the peripheral nerves that is most prone to injuries. After injury, the connection between the nervous system and the distal organs is disrupted, and delayed treatment results in distal organ atrophy and total disability. Regardless of great advances in the fields of neurosurgery, biological sciences, and regenerative medicine, total functional recovery is yet to be achieved.

Areas covered: Cell-based therapy for the treatment of peripheral nerve injuries (PNIs) has brought a new perspective to the field of regenerative medicine. Having the ability to differentiate into neural and glial cells, stem cells enhance neural regeneration after PNIs. Augmenting axonal regeneration, remyelination, and muscle mass preservation are the main mechanisms underlying stem cells’ beneficial effects on neural regeneration.

Expert opinion: Despite the usefulness of employing stem cells for the treatment of PNIs in pre-clinical settings, further assessments are still needed in order to translate this approach into clinical settings. Mesenchymal stem cells, especially adipose-derived stem cells, with the ability of autologous transplantation, as well as easy harvesting procedures, are speculated to be the most promising source to be used in the treatment of PNIs.  相似文献   

109.
110.
Folliculogenesis describes the process of activating an oocyte-containing primordial follicle from the ovarian reserve and its development to the mature ovulatory stage. This process is highly complex and is controlled by extra- and intra-ovarian signaling events. Oocyte competence and capacity for fertilization to support a viable pregnancy are acquired during folliculogenesis. Cancer and cancer-based therapies can negatively affect this process, compromising fertility. Currently, preservation of fertility in these patients remains limited to surrogacy, oocyte freezing, oocyte donation, or in vitro maturation (IVM). Recent reports of stem cells being used to produce fully competent oocytes and subsequently healthy offspring in mice have opened up a novel avenue for fertility preservation. However, translating these findings into human health first relies on enhancing our understanding of follicle growth and mimicking its intricacies in vitro. Indeed, the future of oocytes from stem cells in humans comes with many possibilities but currently faces several technical and ethical obstacles.  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