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   390篇
  免费   12篇
  国内免费   35篇
耳鼻咽喉   6篇
儿科学   12篇
基础医学   31篇
口腔科学   12篇
临床医学   50篇
内科学   48篇
皮肤病学   6篇
神经病学   24篇
特种医学   92篇
外科学   61篇
综合类   22篇
预防医学   8篇
眼科学   5篇
药学   23篇
肿瘤学   37篇
  2023年   3篇
  2021年   6篇
  2020年   1篇
  2019年   2篇
  2018年   5篇
  2017年   3篇
  2016年   2篇
  2015年   1篇
  2014年   9篇
  2013年   10篇
  2012年   6篇
  2011年   6篇
  2010年   4篇
  2009年   10篇
  2008年   14篇
  2007年   22篇
  2006年   12篇
  2005年   28篇
  2004年   10篇
  2003年   5篇
  2002年   5篇
  2001年   13篇
  2000年   8篇
  1999年   10篇
  1998年   17篇
  1997年   19篇
  1996年   25篇
  1995年   14篇
  1994年   12篇
  1993年   26篇
  1992年   3篇
  1991年   7篇
  1990年   5篇
  1989年   14篇
  1988年   16篇
  1987年   10篇
  1986年   8篇
  1985年   6篇
  1984年   14篇
  1983年   9篇
  1982年   8篇
  1981年   7篇
  1980年   3篇
  1979年   3篇
  1978年   4篇
  1977年   4篇
  1976年   3篇
  1975年   3篇
  1968年   1篇
  1963年   1篇
排序方式: 共有437条查询结果,搜索用时 37 毫秒
1.
OBJECTIVES: To compare the relative amounts of elastase (primary polymorphonuclear leucocyte granule constituent) and lactoferrin (secondary PMN granule constituent) in the gingival crevicular fluid (GCF) of healthy, gingivitis and periodontitis sites.
DESIGN: This cross-sectional study looked at the two GCF constituents in three categories of disease status within the same subject.
MATERIALS AND METHODS: Patients with chronic adult periodontitis were screened and those exhibiting all three types of sites ie periodontally healthy, gingivitis and periodontitis sites were recruited (n = 10) and had GCF collected from the three sites. Lactoferrin and elastase were measured in eluates of GCF by enzyme-linked immunosorbent assay.
RESULTS: The absolute amount of lactoferrin measured in ng per 30 s samples was significantly lower in healthy and gingivitis sites as compared to periodontitis sites however this difference failed to reach significance when the concentration of lactoferrin in GCF was used as the analytical unit. No significant differences were found for elastase levels at any sites when expressed as either absolute amounts or concentrations. Secondary granule release, as evidenced by lactoferrin levels, occurs during cell migration and the process is independent of primary granule release, which is thought to correlate with PMN activation. The relationship between granule constituents in the samples showed significant differences, the highest lactoferrinlelastase ratio being at periodontitis sites (P < 0.001).
CONCLUSIONS These findings imply a change in the relative amounts of elastase and lactoferrin released at different disease level sites, with an almost 10-fold increase in the proportion of lactoferrin to elastase in periodontitis sites over healthy and gingivitis sites. This variation in the release by PMNs of primary and secondary granule constituents may indicate alterations in PMN function in different disease environments.  相似文献   
2.
3.
目的:观察认知矫正治疗对慢性精神分裂症患者临床症状和社会功能的改善作用。方法:选择2003-01/08在北京回龙观医院住院的慢性精神分裂症患者104例。均符合CCMD-Ⅲ及DSM-Ⅳ关于精神分裂症诊断标准;年龄25~55岁;病程≥2年;病情稳定,处于迁延、残留或部分缓解状态;药物治疗状况稳定,近期无换药打算;纳入对象或家属同意入组并签署知情同意书。应用随机数字表法将患者分认知矫正治疗组和对照组,每组52例。在相近药物治疗的基础上,认知矫正治疗组以Ann Delahunty和Rodney Morice等制定的神经认知矫正手册(汉化)为治疗工具,在治疗师的指导下进行认知作业练习,内容包括认知灵活性、工作记忆、计划执行功能3大功能模块。对照组予以相同时间的工娱治疗,主要包括有治疗师指导的操作性音乐治疗和舞蹈治疗。治疗前后两组患者分别进行PANSS、住院精神患者社会功能缺陷量表和护士观察量表的评定。结果:实验共纳入慢性精神分裂症患者104例,认知矫正治疗组44例,对照组46例进入结果分析,14例脱落。①治疗前后两组患者PANSS量表总分以及阴性症状量表、复合量表、一般精神病理量表、反应缺乏量表4个分量表的评分均有下降,组内比较差异有显著性意义(t=2.12~4.59,P<0.05);减分情况在两组间差异不明显(P>0.05)。②两组患者的社会功能缺陷量表总分在治疗后均有下降,与治疗前比较,差异有显著性意义(t=3.89,2.04,P<0.05);两组间比较,差异无显著性意义(P>0.05)。认知矫正治疗组治疗后护士观察量表的总病情以及总消极、迟滞2个分量表评分下降,与治疗前比较差异有显著性意义(t=1.49,1.19,2.81,P<0.05);其中迟滞项的减分在两组间比较,差异具有显著性意义(F=4.97,P<0.05)。③社会功能量表的改善与词语流畅性的改善呈正相关(R2=0.36,P<0.05),护士观察量表中总病情与积极两项评分的改善也与言语流畅性测验的改善正相关(R2=0.37,0.34,P<0.05)。结论:认知矫正治疗能在一定程度上改善精神分裂症患者的社会功能,并与部分认知功能的改善相关,但对临床症状无明显改善作用。  相似文献   
4.
BACKGROUND: Granulocyte-colony-stimulating factor (G-CSF) has been used in patients to increase the level of circulating hematopoietic progenitors. Although G-CSF has been administered to some healthy individuals, the kinetics of mobilization of peripheral blood stem cells (PBSCs), the optimum dose schedule and the incidence and nature of adverse reactions in normal individuals are not completely defined. STUDY DESIGN AND METHODS: Normal individuals (n = 102) who received G- CSF for 5 or 10 days at doses of 2, 5, 7.5, or 10 micrograms per kg per day were studied. The subjects were observed for symptoms and physical changes, and blood samples were obtained for a variety of laboratory tests. After 5 or 10 days of G-CSF treatment, PBSCs were collected by apheresis and analyzed. RESULTS: Overall, 89 percent of the individuals completed the 5-day treatment protocol and 88 percent completed the 10- day protocol without modification of the dose of G-CSF administered. Ninety percent of donors experienced some side effect of G-CSF. The most frequent effects noted were bone pain (83%), headache (39%), body aches (23%), fatigue (14%), and nausea and/or vomiting (12%). The dose of G-CSF administered directly affected the proportion of people with bone pain (p = 0.025) or body aches (p = 0.045) or who were feeling hot or having night sweats (p = 0.02) or taking analgesics (p = 0.01). With the 5-day dose schedule, several changes in serum chemistries occurred, including increases in alkaline phosphatase (p = 0.001), alanine aminotransferase (p = 0.0013), lactate dehydrogenase (p = 0.0001), and sodium (p = 0.0001). Decreases occurred in glucose (p = 0.045), potassium (p = 0.0004), bilirubin (p = 0.001), and blood urea nitrogen (p = 0.0017). In donors who received G-CSF for 5 days, the absolute neutrophil count was increased after one G-CSF dose, and it reached a maximum on Day 6, as did the number of CD34+ cells (64.6 +/? 55.9 × 10(6) cells/L). In those same donors, the platelet count after apheresis on Day 6 was 32 +/? 13 percent lower than pretreatment values (250 +/? 42 × 10(9) cells/L). In donors receiving G-CSF for 10 days, the neutrophil count reached a maximum on Day 8, but the number of CD34+ cells peaked on Day 6 (58.3 +/? 52.1 × 10(5) cells/L) and then declined. The platelet count decreased from pretreatment values by 28 +/? 12 percent prior to apheresis on Day 11. When individuals were treated for 5 days with G-CSF, the quantity of CD34+ cells collected was directly related to the G-CSF dose. When 5 micrograms per kg per day was given, 2.80 +/? 1.81 × 10(8) cells were collected, compared with collection of 4.67 +/? 3.11 × 10(8) cells when 10 micrograms per kg per day was given (p = 0.04). More important, PBSCs collected after 10 days of G-CSF administration (5 micrograms/kg/day) had significantly fewer CD34+ cells (0.82 +/? 0.37 × 10(8) cells, p = 0.01) than did PBSCs collected after 5 days of G-CSF (5 micrograms/kg/day). CONCLUSION: Most normal donors receiving G-CSF experience side effects, but these are mild to moderate in degree. Some alterations in blood chemistries occur, but none were clinically serious. Because of the symptoms associated with G-CSF, these individuals must be monitored closely. The treatment of normal donors with G-CSF for more than 5 days significantly decreased the number of circulating CD34+ cells and the quantity collected by apheresis.  相似文献   
5.
HLA and granulocyte-specific antibodies have been implicated in the production of transfusion-related acute lung injury (TRALI). Reported here is a case that suggests that the patient's preexisting condition may play an important role in determining whether TRALI develops upon transfusion of blood products containing anti-white cell (WBC) antibodies. A 29-year-old woman with thrombotic thrombocytopenic purpura (TTP) underwent an uneventful 1.5-volume plasma exchange, which was followed by the transfusion of 2 red cell (RBC) units. At the end of the second RBC transfusion, the patient developed clinical signs and symptoms of noncardiogenic pulmonary edema. Serologic studies demonstrated that the serum from the second RBC donor had no HLA antibodies but did have a granulocyte-specific antibody (anti-NB2) that caused the agglutination of the recipient's granulocytes, which were NB2 positive. Serum from the donor of the first RBC unit and serum from the donors of units used in the exchange had no HLA or granulocyte-specific antibodies that reacted with the recipient's WBCs. Because the donor implicated in this reaction had a history of 21 blood donations, none of which had been associated with a transfusion reaction, we suggest that the patient's preexisting condition played a significant role in this episode of TRALI, owing to the granulocyte-specific antibody.  相似文献   
6.
目的:观察对胃溃疡复发有较好疗效的健胃愈疡颗粒对溃疡黏膜乳腺癌相关肽和血小板活化因子表达的影响,分析其可能的作用机制。方法:实验于2005-07/2006-07在湘雅医院中心实验室完成。SD大鼠110只,雌雄各半,随机抽签法分为5组,即正常对照组、假手术组、雷尼替丁组、健胃愈疡组,各20只;模型组30只。以Okabe改良法复制大鼠实验性胃溃疡,假手术组仅以生理盐水代替乙酸注入玻管内。造模后24h,雷尼替丁组、健胃愈疡组大鼠分别灌服盐酸雷尼替丁和健胃愈疡颗粒(药物组成为:柴胡、党参、白芍、延胡索、白芨、珍珠层粉、青黛、甘草,湖南湘雅制药有限公司生产)药液10mL/kg,分别相当于2.70,1.62g/kg,1次/d。假手术组、模型组灌服蒸馏水10mL/kg。10d后各组中随机取出10只大鼠剖腹取胃(处死前大鼠禁食24h),90d时将模型组20只大鼠再分为模型复发组和模型非复发组,各10只;除正常对照组、假手术组、模型非复发组大鼠腹腔内注射生理盐水外,其余各组大鼠腹腔内注射白细胞介素1,1μg/kg;在注射48h,大鼠禁食24h后,剖腹取胃。观察其对胃溃疡大鼠胃黏膜氨基己糖及磷脂含量、溃疡指数和胃黏膜血流的影响,并用RT-PCR观察乳癌相关肽乳癌相关肽和血小板活化因子表达的变化。结果:实验动物110只,全部进入结果分析。①模型组10,92d胃黏膜血流均低于正常对照组(P<0.01);健胃愈疡组同期胃黏膜血流均高于模型组(P<0.01)。②健胃愈疡组和雷尼替丁组10d溃疡指数均低于模型组(P<0.01,P<0.05);模型复发组、健胃愈疡组和雷尼替丁组92d溃疡指数均高于模型组(P<0.01);健胃愈疡组10,92d溃疡指数及复发率均低于雷尼替丁组(P<0.05,P<0.01)。③模型组10,92d氨基己糖和磷脂含量均低于正常对照组(P<0.01)。健胃愈疡组10,92d氨基己糖和磷脂含量均高于模型组和雷尼替丁组(P<0.01)。溃疡指数与氨基已糖、磷脂含量呈负相关(r=-0.957,-0.960,P<0.01)。④健胃愈疡组和雷尼替丁组10d乳癌相关肽mRNA表达较正常组和假手术组提高,血小板活化因子mRNA的表达下调(P<0.01),健胃愈疡组两指标表达变化较雷尼替丁组显著(P<0.01);模型复发组、健胃愈疡组和雷尼替丁组92d乳癌相关肽mRNA、血小板活化因子mRNA的表达同组10d比较差异无显著性意义(P>0.05);模型组乳癌相关肽mRNA、血小板活化因子mRNA的表达同组10d比较差异有显著性意义(P<0.01)。结论:健胃愈疡颗粒可提高乳癌相关肽mRNA及下调血小板活化因子mRNA的表达,影响胃黏膜氨基己糖及磷脂含量,可能是其促进溃疡愈合的机制之一。  相似文献   
7.
Bone marrow transplantation (BMT) is now an option for some patients with sickle cell disease (SCD). Many SCD patients are multiply transfused with red blood cells (RBCs), and may be immunized to alloantigens other than erythrocyte antigens. Because platelet refractoriness is a significant complication during BMT, we wished to determine the prevalence of alloimmunization to platelets in transfused SCD patients. Sera collected from 47 transfused and 14 untransfused SCD patients were screened for HLA and platelet-specific antibodies. Transfusion and RBC antibody histories were reviewed. A subset of the patients were rescreened 1 year later. Eighty-five percent of patients with at least 50 RBC transfusions (22 of 26), 48% of patients with less than 50 transfusions (10 of 21), and none of 14 untransfused patients demonstrated platelet alloimmunization (P < .05). Platelet alloimmunization was more prevalent than RBC alloimmunization (20% to 30%). Half of the platelet reactivity was chloroquine-elutable. Eighteen of 22 patients (82%) on chronic RBC transfusion remained platelet-alloimmunized 11 to 22 months after initial testing. In summary, 85% of heavily transfused SCD patients are alloimmunized to HLA and/or platelet-specific antigens. These patients may be refractory to platelet transfusion, a condition that would increase their risk during BMT. Leukodepletion in the transfusion support of SCD patients should be considered to prevent platelet alloimmunization.  相似文献   
8.
ObjectiveTo combine isoniazid (INH) and rifampicin (RIF) in a single media to detect and evaluate multi-drug resistant Mycobacterium tuberculosis (MDR-TB) strains using clinical specimens by direct and indirect drug susceptibility testing (DST).MethodsDrug susceptibility testing for INH and RIF using individual and combined drug media was performed by minimum inhibitory concentration (MIC) method on direct clinical specimens.ResultsThe combined drug media showed complete concordance with individual drug media in the detection of MDR-TB by direct DST method and 89% efficiency with indirect DST method. Susceptibility results were available by 3 weeks after the receipt of clinical specimen using direct DST on combined drug media.ConclusionsCombined drug media can be used as a fast track method in large scale studies warranting detection of MDR-TB.  相似文献   
9.
Klock  JC; Boyles  J; Bainton  DF; Stossel  TP 《Blood》1979,54(6):1216-1229
We have investigated the effects of mechanical elution of neutrophils from nylon-wool fiber (NWF) using the scanning electron microscope and biochemical analysis of elution fractions. We have determined that mechanical removal of neutrophils from nylon-wool fiber disrupts neutrophils adherent to nylon-wool fiber and augments release of granules, release of peripheral cytoplasmic fragments, and release of lactic dehydrogenase, a soluble cytoplasmic enzyme. Mechanical shearing of the adherent cell, and not adherence per se, causes the fragmentation. The extent of fragmentation is proportional to the NWF surface area available to neutrophils and is maximal at the temperature for optimal adherence and spreading. Agents that decrease cell spreading (n-ethylmaleimide and cold) diminish fragmentation. Cytochalasin B, an agent that destabilizes the neutrophil cortex, increases fragmentation. Fragmentation may be an important contributing cause of the abnormal morphology, function, and in vivo survival of nylon-wool-fiber procured human neutrophils. The prevention of fragmentation would appear to be necessary to insure the procurement of optimally functioning cells. Elution of NWF-adherent neutrophils in the cold might be a practical way to diminish neutrophil damage during clinical filtration leukapheresis.  相似文献   
10.
Bowen-Pope  DF; Malpass  TW; Foster  DM; Ross  R 《Blood》1984,64(2):458-469
Platelet-derived growth factor (PDGF) is a potent mitogen for many cultured connective tissue cells. It is present in concentrated form within the platelet alpha-granules and is believed to be released during platelet degranulation at sites of vascular injury. We have used a sensitive radioreceptor assay to measure PDGF levels in whole blood serum from normal humans [17.5 +/- 3.1 (SD) ng/mL] and baboons (2.7 +/- 1.2 ng/mL). PDGF was not detected in plasma from either species. In addition, plasma was found to substantially reduce the ability of added purified PDGF to bind to the cell surface PDGF receptor on cultured cells, suggesting that plasma may contain a PDGF-binding protein that would serve to inactivate PDGF released into plasma. Calculations of PDGF concentrations in serum have been corrected for the effects of the binding protein. 125I-PDGF injected intravenously into normal baboons was cleared rapidly from the plasma (t1/2 = two minutes). The rapid clearance of 125I-PDGF did not result from iodination damage, as purified unlabeled PDGF was cleared with comparable kinetics. The rapid clearance of purified and iodinated PDGF did not result from changes in PDGF structure during purification or from removal of PDGF-associated proteins during purification, as PDGF present in freeze-thaw lysates of fresh platelets was cleared equally rapidly. We conclude that release of PDGF at sites of vascular injury would greatly increase the local concentration of PDGF and that PDGF not localized to the site of injury would be rapidly cleared from the circulation.  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