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   77981篇
  免费   5542篇
  国内免费   2501篇
耳鼻咽喉   447篇
儿科学   1755篇
妇产科学   843篇
基础医学   10658篇
口腔科学   941篇
临床医学   6168篇
内科学   15632篇
皮肤病学   1288篇
神经病学   5135篇
特种医学   1044篇
外国民族医学   11篇
外科学   5533篇
综合类   9636篇
现状与发展   10篇
预防医学   6089篇
眼科学   1050篇
药学   12360篇
  21篇
中国医学   3761篇
肿瘤学   3642篇
  2023年   1061篇
  2022年   1509篇
  2021年   2724篇
  2020年   2435篇
  2019年   3014篇
  2018年   3017篇
  2017年   2542篇
  2016年   2489篇
  2015年   2742篇
  2014年   4752篇
  2013年   5502篇
  2012年   4628篇
  2011年   5350篇
  2010年   4318篇
  2009年   3790篇
  2008年   3600篇
  2007年   3233篇
  2006年   2833篇
  2005年   2442篇
  2004年   2117篇
  2003年   1881篇
  2002年   1525篇
  2001年   1402篇
  2000年   1067篇
  1999年   1082篇
  1998年   843篇
  1997年   708篇
  1996年   554篇
  1995年   603篇
  1994年   551篇
  1993年   601篇
  1992年   540篇
  1991年   491篇
  1990年   433篇
  1989年   364篇
  1988年   342篇
  1987年   243篇
  1986年   242篇
  1985年   902篇
  1984年   1152篇
  1983年   878篇
  1982年   1036篇
  1981年   925篇
  1980年   699篇
  1979年   654篇
  1978年   474篇
  1977年   373篇
  1976年   432篇
  1975年   331篇
  1973年   216篇
排序方式: 共有10000条查询结果,搜索用时 25 毫秒
1.
内生菌由细菌、真菌、古菌和原生生物组成,它们生活在植物的活体组织中,具有丰富的次级代谢产物多样性。人参内生菌在人参的生长发育、次级代谢产物的生成和环境适应等方面均有重要的促进作用,对人参的产量和品质有较大影响。随着人们在微生物领域研究的深入,高通量测序技术已经成为研究植物内生菌的重要方法。文章主要从人参内生菌分离与鉴定研究方法、人参内生菌的多样性、人参内生菌及其次级代谢产物的活性、人参内生菌对宿主的影响等4个方面对人参内生菌近年来的研究进展进行讨论,并对其发展方向提出展望,以期为药用植物内生菌研究和品质改良提供新思路、新方法。  相似文献   
2.
Lessons Learned
  • SCB01A is a novel microtubule inhibitor with vascular disrupting activity.
  • This first‐in‐human study demonstrated SCB01A safety, pharmacokinetics, and preliminary antitumor activity.
  • SCB01A is safe and well tolerated in patients with advanced solid malignancies with manageable neurotoxicity.
BackgroundSCB01A, a novel microtubule inhibitor, has vascular disrupting activity.MethodsIn this phase I dose‐escalation and extension study, patients with advanced solid tumors were administered intravenous SCB01A infusions for 3 hours once every 21 days. Rapid titration and a 3 + 3 design escalated the dose from 2 mg/m2 to the maximum tolerated dose (MTD) based on dose‐limiting toxicity (DLT). SCB01A‐induced cellular neurotoxicity was evaluated in dorsal root ganglion cells. The primary endpoint was MTD. Safety, pharmacokinetics (PK), and tumor response were secondary endpoints.ResultsTreatment‐related adverse events included anemia, nausea, vomiting, fatigue, fever, and peripheral sensorimotor neuropathy. DLTs included grade 4 elevated creatine phosphokinase (CPK) in the 4 mg/m2 cohort; grade 3 gastric hemorrhage in the 6.5 mg/m2 cohort; grade 2 thromboembolic event in the 24 mg/m2 cohort; and grade 3 peripheral sensorimotor neuropathy, grade 3 elevated aspartate aminotransferase, and grade 3 hypertension in the 32 mg/m2 cohort. The MTD was 24 mg/m2, and average half‐life was ~2.5 hours. The area under the curve‐dose response relationship was linear. Nineteen subjects were stable after two cycles. The longest treatment lasted 24 cycles. SCB01A‐induced neurotoxicity was reversible in vitro.ConclusionThe MTD of SCB01A was 24 mg/m2 every 21 days; it is safe and tolerable in patients with solid tumors.  相似文献   
3.
4.
对2010年1月—2016年7月重庆市中毒救治指定医疗机构收治的2 497例中毒患者进行回顾性分析。结果显示,中毒患者中男性1 230例(49.3%)、女性1 267例(50.7%);分布最多的3个年龄段依次是41~50岁(18.5%)、≤10岁(16.4%)和21~30岁(13.0%);死亡16例,病死率0.6%。中毒类型构成排前三位的是细菌(33.8%)、化学品(32.2%)、植物(14.8%)。中毒预后多因素Logistic回归分析结果显示重度中毒患者结局死亡的可能性是轻度患者的1 102倍。提示重庆市应重点关注农村地区41~50岁人群的细菌、化学品、药物中毒,同时应该加强儿童中毒防控工作。  相似文献   
5.
Abstract

Endometriosis is one of the most common gynecological diseases and a major cause of pain and infertility. It is influenced by genetic, epigenetic, and environmental factors. Recently, genome-wide association studies have revealed a strong association between IL1A single nucleotide polymorphisms (SNPs) and increased risk of endometriosis in Japanese women. The aim of the present study was to evaluate the association of three IL1A SNPs, rs17561, rs1304037, and rs2856836 with the risk of endometriosis in Iranian population. Totally, 105 women with diagnosis of endometriosis and 102 healthy women as control group were included. Three SNPs of the IL1A, rs17561?G/T, rs1304037 A/G, and rs2856836 T/C, were genotyped by PCR and RFLP. The rs2856836?TC genotype was significantly higher (p?=?.002; OR?=?3.1, 95% CI: 1.5–6.5) in the patients (28.1%) than the control group (12.7%). The rs2856836?CC genotype was significantly higher (p?=?.047; OR?=?2.3, 95% CI: 1.0–5.3) in the patients (17.5%) than the control group (10.8%). The rs2856836 C allele was significantly higher (p?=?.001; OR?=?2.2, 95% CI: 1.4–3.6) in the patients (31.6%) than the control group (17.2%). The IL1A rs2856836 T/C SNP was associated with susceptibility to endometriosis and the rs2856836 C allele may increase the risk of endometriosis in Iranian women.  相似文献   
6.
Gut bacteria and gut barrier plays important roles in body homeostasis. Ciprofloxacin (CPFX) is widely used to treat bacterial infections. However, whether high dosage of CPFX has side effects on gut barrier integrity is still unclear. Our results indicated that the High CPFX treatment (1 mg/ml) caused weight loss, nervousness, anorexia, and increased apoptosis cells in gut, but less influence was observed in the Low CPFX group (0.2 mg/ml). Meanwhile, the High CPFX treatment impaired tight junction molecules Ocln/ZO-1 level and down-regulated antibacterial genes expression (reg3γ, pla2g2α and defb1). Further, the High CPFX treatment increased pro-inflammatory cytokine IL-1β in intestinal tract, decreased IL-17A of duodenum but increased IL-17A of colon at day 37. In addition, the gut bacterial diversity and richness behaved significantly loss regarding CPFX treatment, especially in the High CPFX group during the experiment. Indole exhibited sharply decline in both Low and High CPFX groups at day 7, and the High CPFX mice needed longer time on restoring indole level. Meanwhile, CPFX treatment strongly decreased the concentrations of butyric acid and valeric acid at day 1. Correlation analysis indicated that the linked patterns between the key bacteria (families Bacteroidales_S247, Ruminococcaceae and Desulfovibrionaceae) and metabolites (indole and butyric acid) were disturbed via the CPFX treatment. In conclusion, the High CPFX treatment impaired the gut barrier with the evidence of reduced expression of tight junction proteins, increased apoptosis cells and inflammatory cells, decreased the bacterial diversity and composition, which suggesting a proper antibiotic-dosage use should be carefully considered in disease treatment.  相似文献   
7.
目的对治疗前原发性骶尾部脊索瘤(PSC)CT图像分型,并分析其CT征象,为诊断和个性化治疗提供依据。方法回顾性分析101例PSC患者治疗前的CT图像,包括肿瘤的部位、范围、大小、密度、肿瘤与邻近结构的关系。按照肿瘤的部位由上及下分为Ⅰ~Ⅳ型,并根据肿瘤侵犯的范围从小到大分为a^d亚型。采用Kruskal-Wallis H检验比较PSC各亚型的占比,并对各亚型之间进行两两比较。采用R×C列联表精确概率检验比较分型和亚型肿瘤钙化的发生率。采用单因素方差分析及LSD-t检验对各分型和亚型肿瘤的大小和密度进行分析、比较。结果101例PSC中,Ⅰ~Ⅳ型的发生率分别为17.8%、30.7%、36.6%、14.9%,a^d亚型的占比分别为9.9%、25.7%、58.4%、5.9%。各亚型的占比差异具有统计学意义(P=0.012)。c亚型明显高于a亚型(P=0.039),d亚型明显低于a亚型(P=0.036),其余各型之间无明显差异。各分型肿瘤内钙化的差异无统计学意义(P=0.233);各亚型肿瘤内钙化的差异有统计学意义(P=0.003),a^d亚型肿瘤钙化的比率逐渐增加。Ⅰ型肿瘤的左右径及上下径明显大于Ⅱ~Ⅳ型(P<0.05)。a亚型与b亚型肿瘤之间前后径的差异无统计学意义(P=0.102),b^d亚型之间前后径的差异均有统计学意义(P<0.05);不同亚型肿瘤之间的左右径、上下径之间的差异均有统计学意义(P<0.05),a亚型径线最小,d亚型径线最大。结论101例PSC中,Ⅱ、Ⅲ型最多见,肿瘤较少累及第一骶骨;各亚型中,a型较少见,c亚型最多见,d亚型最少见。肿瘤的密度与分型无关,肿瘤内钙化与亚型有关。Ⅰ型肿瘤侵犯的范围较Ⅱ~Ⅳ型广泛,a^d亚型肿瘤的径线逐渐增大,CT分型有利于判断肿瘤的范围。PSC诊断延迟现象比较明显,但很少发生远处侵犯和转移。CT图像可对治疗前PSC分型,为诊断和个性化治疗提供依据。  相似文献   
8.
9.
ResearchGate is a world wide web for scientists and researchers to share papers, ask and answer questions, and find collaborators. As one of the more than 15 million members, the author uploads research output and reads and responds to some of the questions raised, which are related to type 2 diabetes. In that way, he noticed a serious gap of knowledge of this disease among medical professionals over recent decades. The main aim of the current study is to remedy this situation through providing a comprehensive review on recent developments in biochemistry and molecular biology, which can be helpful for the scientific understanding of the molecular nature of type 2 diabetes. To fill up the shortcomings in the curricula of medical education, and to familiarize the medical community with a new concept of the onset of type 2 diabetes, items are discussed like: Insulin resistance, glucose effectiveness, insulin sensitivity, cell membranes, membrane flexibility, unsaturation index (UI; number of carbon-carbon double bonds per 100 acyl chains of membrane phospholipids), slow-down principle, effects of temperature acclimation on phospholipid membrane composition, free fatty acids, energy transport, onset of type 2 diabetes, metformin, and exercise. Based on the reviewed data, a new model is presented with proposed steps in the development of type 2 diabetes, a disease arising as a result of a hypothetical hereditary anomaly, which causes hyperthermia in and around the mitochondria. Hyperthermia is counterbalanced by the slow-down principle, which lowers the amount of carbon-carbon double bonds of membrane phospholipid acyl chains. The accompanying reduction in the UI lowers membrane flexibility, promotes a redistribution of the lateral pressure in cell membranes, and thereby reduces the glucose transporter protein pore diameter of the transmembrane glucose transport channel of all Class I GLUT proteins. These events will set up a reduction in transmembrane glucose transport. So, a new blood glucose regulation system, effective in type 2 diabetes and its prediabetic phase, is based on variations in the acyl composition of phospholipids and operates independent of changes in insulin and glucose concentration. UI assessment is currently arising as a promising analytical technology for a membrane flexibility analysis. An increase in mitochondrial heat production plays a pivotal role in the existence of this regulation system.  相似文献   
10.
Trigeminal neuralgia is a debilitating condition, and the pain easily spreads to other parts of the face. Here, we established a mouse model of partial transection of the infraorbital nerve (pT-ION) and found that the Connexin 36 (Cx36) inhibitor mefloquine caused greater alleviation of pT-ION-induced cold allodynia compared to the reduction of mechanical allodynia. Mefloquine reversed the pT-ION-induced upregulation of Cx36, glutamate receptor ionotropic kainate 2 (GluK2), transient receptor potential ankyrin 1 (TRPA1), and phosphorylated extracellular signal regulated kinase (p-ERK) in the trigeminal ganglion. Cold allodynia but not mechanical allodynia induced by pT-ION or by virus-mediated overexpression of Cx36 in the trigeminal ganglion was reversed by the GluK2 antagonist NS102, and knocking down Cx36 expression in Nav1.8-expressing nociceptors by injecting virus into the orofacial skin area of Nav1.8-Cre mice attenuated cold allodynia but not mechanical allodynia. In conclusion, we show that Cx36 contributes greatly to the development of orofacial pain hypersensitivity through GluK2, TRPA1, and p-ERK signaling.Electronic supplementary materialThe online version of this article (10.1007/s12264-020-00594-4) contains supplementary material, which is available to authorized users.  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