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   3919篇
  免费   337篇
  国内免费   215篇
耳鼻咽喉   20篇
儿科学   47篇
妇产科学   57篇
基础医学   510篇
口腔科学   68篇
临床医学   434篇
内科学   414篇
皮肤病学   78篇
神经病学   137篇
特种医学   152篇
外国民族医学   5篇
外科学   485篇
综合类   860篇
现状与发展   2篇
预防医学   229篇
眼科学   46篇
药学   376篇
  6篇
中国医学   238篇
肿瘤学   307篇
  2024年   30篇
  2023年   71篇
  2022年   156篇
  2021年   205篇
  2020年   163篇
  2019年   126篇
  2018年   143篇
  2017年   141篇
  2016年   140篇
  2015年   183篇
  2014年   212篇
  2013年   187篇
  2012年   271篇
  2011年   261篇
  2010年   186篇
  2009年   135篇
  2008年   189篇
  2007年   172篇
  2006年   154篇
  2005年   140篇
  2004年   96篇
  2003年   116篇
  2002年   148篇
  2001年   76篇
  2000年   102篇
  1999年   146篇
  1998年   88篇
  1997年   90篇
  1996年   72篇
  1995年   50篇
  1994年   43篇
  1993年   30篇
  1992年   23篇
  1991年   23篇
  1990年   26篇
  1989年   11篇
  1988年   23篇
  1987年   13篇
  1986年   14篇
  1985年   4篇
  1984年   4篇
  1983年   4篇
  1981年   3篇
  1980年   1篇
排序方式: 共有4471条查询结果,搜索用时 31 毫秒
1.
目的:建立鼠巨细胞病毒(MCMV)感染C57BL/6小鼠急性肝炎模型并对其感染特点进行分析及鉴定。方法:将24 只C57BL/6小鼠随机分为阴性对照组(n =12)及病毒感染组(n =12),病毒感染组腹腔注射1.0×106 PFU(200 μL)MCMV悬液,阴性对照组注射等体积小鼠胚胎成纤维细胞(MEF)悬液。于感染后第3天和第7天取外周血分离血清检测谷丙转氨酶(ALT)及谷草转氨酶(AST)。同时进行肝组织病毒分离、组织病理学及MCMV IE和M55基因、细胞因子白细胞介素-6(IL-6)、白细胞介素-1β(IL-1β)、肿瘤坏死因子α(TNF-α)的检测。结果:病毒感染组肝组织匀浆病毒分离均为阳性,肝炎发生率为100%。在感染后第3天即发生肝炎病理改变,病毒感染组血清ALT及AST较阴性对照组明显升高(P <0.01);病毒感染组肝脏HE染色第3天可见局灶性炎性细胞浸润及肝脏点灶状坏死,持续至第7天,Ishak评分较阴性对照组明显升高(P <0.01);在感染后第3天病毒感染组肝组织内可检测到MCMV IE及M55基因,且在感染后第7天仍可测得IE基因;感染后第3天及第7天病毒感染组炎性细胞因子IL-6、TNF-α及IL-1β mRNA表达水平明显升高(P <0.05)。 结论:成功建立MCMV感染C57BL/6小鼠急性动物肝炎模型,其感染表现主要集中在急性感染前期。  相似文献   
2.
同种原位肝移植围手术期的处理   总被引:1,自引:0,他引:1  
目的 总结我院自1999年8月以来,开展的3例同种异体原位肝移植(Orthotopic livertransplantation,OLT)围手术期的处理过程及经验体会。方法 2例原位肝移植、1例肝-肾联合移植术。均在术前12h口服环孢霉素A(CsA)和骁悉(MAP),术中用甲基强的松龙(MP)1000 mg静脉冲击防止排斥,术后MP+CsA+MAP三联用药。结果 ①文中3例病人手术均获成功,其中2例原位肝移植病人存活至今,生活质量良好。肝肾联合移植病人于术后第76d死于严重混合感染。②移植肝的功能维护是肝移植术后处理的重点,其中包括急性排斥反应的诊断和处理,以及其它可能引起肝移植肝功能损害、衰竭等问题的处理。③全身非移植器官的功能恢复:包括呼吸系统、感染、出血、胸水、腹水等并发症的处理过程。结论 肝移植围手术期的处理是肝移植成功与否的关键,其中包括肝移植的排斥反应及各系统的功能支持与维护。  相似文献   
3.

Background  

Climate change is taking a toll on human health, and some leaders in the public health community have urged their colleagues to give voice to its health implications. Previous research has shown that Americans are only dimly aware of the health implications of climate change, yet the literature on issue framing suggests that providing a novel frame - such as human health - may be potentially useful in enhancing public engagement. We conducted an exploratory study in the United States of people's reactions to a public health-framed short essay on climate change.  相似文献   
4.
Itiswellknownthatcertaincytokinesplayapivotalroleinthedevelopmentoftraumaandshock.Tumornecrosisfactor(TNF)isapolypep-tiedcytokinesynthesizedinmonocytesandmacrophagesinresponsetolipopolysaccharide(LPS)stimulation-TherelationshipbetweenTNFandendotoxic-septicshockbecomesafocusoftheresearchofshockmediators[1'2].Alargeamountofexperimentalandclinicaldata[3-9JsuggestthatTNFplaysanimportantroleinthepathogenesisofendotoxic-septicshockbuttheprecisemechanismandtherelationshipofTNFtoshockseverityrem…  相似文献   
5.
SUMMARY: The effect of mild acute tubular injury on the progression of tubulointerstitial fibrosis was studied in pair-fed uninephrectomized male Wistar rats with established adriamycin nephrosis ( n = 34). Rats were stratified into three groups according to endogenous creatinine clearance (CrCl), proteinuria (Upr) and body weight (BW): (i) group 1 (Fe, n = 12) received a single intraperitoneal injection of ferric nitrilotriacetate (5 mg Fe/kg BW); (ii) group 2 (G, n = 10) three daily subcutaneous injections of gentamicin (60 mg/kg BW) and; (iii) group 3 (C, n = 12) saline injections. Serial CrCl (day 2, day 5, weeks 2, 4, 6 and 8) and renal histology (week 8) were examined following administration of nephrotoxin. CrCl was reduced on d2 (Fe: 0.78 ± 0.23 mL/min; mean ± SD) and day 5 (G: 0.91 ± 0.36 mL/min) as compared with C (1.22 ± 0.12 mL/min; P <0.05). There was no change in the serum creatinine and functional recovery occurred by d5 (Fe) and week 2 (G). Upr decreased transiently in G at week 2 (G: 482 ± 208 mg/day vs C: 716 ± 233; P = 0.05) despite similar food intake, baseline Upr and CrCl. At week 8, CrCl in Fe (0.84 ± 0.40 mL/min) was similar to C (0.84 ± 0.58 mL/min), whereas in G it remained stable (1.27 ± 0.39 mL/min; P <0.05). By morphometric analysis, mean relative interstitial volume (RIV) and glomerulosclerosis (GS) in Fe (RIV: 28.5 ± 13.4%; GS: 10.3 ± 12.3%) was no different to C (RIV: 24.5 ± 12.5%; GS: 20.9 ± 20.0%), whereas both parameters were reduced in G (RIV: 14.1 ± 8.1%; GS: 4.0 ± 4.8%; P <0.05). Mild gentamicin nephrotoxicity therefore reduced the progression of adriamycin nephrosis. the mechanism of this finding is unclear, but it may relate to altered glomerular and tubular cell handling of protein.  相似文献   
6.
Comet assay is a useful technique in the detection of DNA damages, particularly DNA strand breaks; and it has been utilized to show that a potent carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), can induce such damages. Recently, gammaH2AX foci formation has been suggested as another sensitive way to detect DNA double strand breaks (DSBs). However, there is no systematic comparison being conducted to evaluate the consistency of these two methods. Using MNNG as a model chemical, the sensitivity of neutral comet assay and gammaH2AX foci formation in detecting MNNG-induced damage was studied. It was found that at concentrations of 0.1 and 1 microg/ml, both methods can detect MNNG-induced damage in human amnion FL cells. However, at 0.1 microg/ml, comet assay revealed more percentage of cells with DNA damage than gammaH2AX fluorescence revealed. On the other hand, while gammaH2AX foci were readily formed at very early times by 10 microg/ml MNNG treatment, neutral comet assay did not detect any significant DNA damage at the same time points. In addition, 10 microg/ml MNNG induced a distinct whole nuclei staining pattern of gammaH2AX, a type of DNA damage which was not detected by neutral comet assay but could be detected by alkaline comet assay. Therefore, gammaH2AX may be used as a sensitive indicator for DNA damage.  相似文献   
7.
内镜治疗甲状腺功能亢进7例报告   总被引:4,自引:1,他引:3  
目的总结内镜治疗甲状腺功能亢进(甲亢)的经验。方法7例原发性或继发性甲亢,内镜经胸人路行甲状腺全切或次全切除术。结果7例手术均成功,无中转开放手术。手术时间130~260min,平均168min;术中出血量10~200ml,平均70ml。无喉返、喉上神经损伤,无术后出血等并发症。术后恢复良好,近期随访美容效果满意。随访1~12个月,平均5.1月,无复发,2例出现甲状腺功能低下,1例在术后2个月时恢复。结论内镜治疗甲亢技术安全、可行。除常规手术前甲亢准备外,必须行CT检查确认腺体大小,确定残留腺体的大小和位置。  相似文献   
8.
日本血吸虫感染小鼠脾细胞IL—2及IFN—γ动态观察   总被引:4,自引:0,他引:4  
本文观察8wk龄C57BL/6小鼠感染日本血吸虫尾蚴后不同时期脾细胞经SEA或ConA刺激,体外诱生的IL-2和IFN-γ活性变化。结果表明两种细胞因子活性均在感染后第4-6wk开始上升,第6—8wk达高峰,第12—14wk恢复至感染前水平。IFN-γ高峰时间略先于IL-2。非特异性刺激原诱生组和特异性刺激原诱生组各阶段细胞因子活性动态基本一致,前组活性高于后组。提示IFN-γ与IL-2活性与血吸虫卵肉芽肿的诱导、成熟与维持有密切关系。  相似文献   
9.
140 patients with brain tumor were treated by CT-guided stereotactic injections of radionuclides, such as Aurum-198 (198 Au), Phosphorus-32 (32 P) and Yttrium-90 (90Y). Of these patients aged from 3 to 67 years (average 37), 64 were male and 76 female. Astrocytoma was found in 75 patients, craniopharyngioma in 46, metastatic carcinoma in 7, meningioma in 5, germinoma in 4 and pituitary adenoma in 3. The tumors were located in the deep part or functionally critical area of the brain. After 267 times of injection of colloidal isotopes, no major adverse effects or complications occurred. Follow-up for 6 to 48 months showed improvement in symptoms in 104 (74.3%) patients and CT scanning showed the diminished tumors.
  相似文献   
10.
Small vessels in three-dimensional MR angiograms have low visibility in maximum-intensity projection images because of their low contrast. In a previous study, we had two nonlinear filters that appeared to give significant improvement in small vessel detail. In this paper, we report on a generalization of this filter that allows a more general modeling of the vessels and a more complete suppression of background. One implementation of the general filter gave a vessel mean contrast-to-noise ratio that is 2.52 and 3.51 times higher than the vessel mean contrast-to-noise ratio obtained using our previously reported maximum-minimum (max-min) filter and cross- section filter, respectively.  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