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   678篇
  免费   54篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   30篇
妇产科学   1篇
基础医学   100篇
口腔科学   44篇
临床医学   54篇
内科学   124篇
皮肤病学   22篇
神经病学   18篇
特种医学   101篇
外科学   90篇
综合类   26篇
预防医学   34篇
眼科学   8篇
药学   63篇
中国医学   1篇
肿瘤学   21篇
  2021年   18篇
  2020年   6篇
  2019年   3篇
  2018年   6篇
  2017年   5篇
  2016年   16篇
  2015年   13篇
  2014年   14篇
  2013年   30篇
  2012年   25篇
  2011年   18篇
  2010年   30篇
  2009年   30篇
  2008年   22篇
  2007年   16篇
  2006年   24篇
  2005年   14篇
  2004年   9篇
  2003年   16篇
  2002年   21篇
  2001年   14篇
  2000年   11篇
  1999年   23篇
  1998年   37篇
  1997年   26篇
  1996年   26篇
  1995年   15篇
  1994年   22篇
  1993年   25篇
  1992年   8篇
  1991年   8篇
  1990年   5篇
  1989年   15篇
  1988年   28篇
  1987年   11篇
  1986年   21篇
  1985年   9篇
  1984年   11篇
  1983年   6篇
  1982年   11篇
  1981年   13篇
  1980年   13篇
  1979年   4篇
  1978年   11篇
  1977年   7篇
  1976年   13篇
  1975年   4篇
  1967年   1篇
  1957年   1篇
  1955年   1篇
排序方式: 共有739条查询结果,搜索用时 15 毫秒
81.
We show that a common polymorphic variant in the ERCC5 5′ untranslated region (UTR) generates an upstream ORF (uORF) that affects both the background expression of this protein and its ability to be synthesized following exposure to agents that cause bulky adduct DNA damage. Individuals that harbor uORF1 have a marked resistance to platinum-based agents, illustrated by the significantly reduced progression-free survival of pediatric ependymoma patients treated with such compounds. Importantly, inhibition of DNA-PKcs restores sensitivity to platinum-based compounds by preventing uORF1-dependent ERCC5 expression. Our data support a model in which a heritable 5′ noncoding mRNA element influences individuals’ responses to platinum-based chemotherapy.  相似文献   
82.
Fabrication of polymer-nanoparticle nanocomposites typically relies on mixing nanoparticle and polymer solutions, which renders little control over nanoparticle incorporation, and homogeneity of the resulting composite material. This work focuses on the thermally induced embedment of monocrystalline silver nanocubes (AgNCs) into polymer surfaces. The AgNCs are initially deposited through a Langmuir approach onto films of immiscible blended polymer films, which allows fine control over nanoparticle density and aggregation state. This nanoparticle/polymer composite is then heated above the glass transition temperature (Tg) of a polymer, which initiates the irreversible embedding of the AgNCs. The immiscible ternary polymer films featured discrete domains (with different Tgs), which were altered by changing the amount of polystyrene, poly(2-vinylpyridine) and poly(methyl methacrylate) within the polymer solution. The Tg dependence of the embedding process allowed the selective embedment of AgNCs into discrete polymer domains. The process was monitored in real time by using spatially separated hybrid plasmon modes, through peak shifts observed in a UV-vis spectrum. Enhanced surface confinement was observed for certain tripolymer films when compared to polystyrene–AgNC nanocomposites, due to changes in the surface energy within the blend. This work brings interesting insight on nanoparticle-blended polymer interactions and provides a fairly universal approach for the fabrication of these polymer–metal nanoparticle nanocomposites, which is of particular interest in fields that require fine control over nanoparticle incorporation within segregated polymer domains.

Thermally induced incorporation of plasmonic nanoparticles into specific polymer domains in a thin film is achieved and monitored in real time.  相似文献   
83.
Giles  AR; Nesheim  ME; Hoogendoorn  H; Tracy  PB; Mann  KG 《Blood》1982,59(2):401-407
In vitro evaluation of prothrombin complex concentrates in a thrombin generation assay, using DAPA and purified components of the prothrombinase complex, demonstrated significant levels of coagulant- active "phospholipid replacing" activity. Quantification of this activity showed a significant correlation (r = 0.8747, p less than 0.01) with thrombogenicity measured in vivo in a stasis model in rabbits. Extracted lipid material retained full phospholipid replacing activity in the vitro assay. Thin-layer chromatographic characterization confirmed the presence of phospholipids with known coagulant activity in vitro. In vivo, the extracted material was nonthrombogenic but augmented the thrombogenicity of purified factor Xa. Substitution of a synthetic coagulant-active phospholipid (phosphatidylcholine-phosphatidylserine lipid vesicles) for the extracted phospholipid produced a similar augmentation of a factor-Xa- induced thrombogenicity in vivo. It is concluded that the coagulant- active phospholipid content of prothrombin complex concentrates is a major determinant of thrombogenicity but requires the presence of activated clotting factors for its expression in vivo.  相似文献   
84.
Type II mixed cryoglobulinemia (MC) is an often progressive vasculitis characterized by circulating cold-precipitable proteins that usually consists of polyclonal IgG and monoclonal IgM kappa with rheumatoid factor (RF) activity. Its etiology is unknown, although recent evidence strongly suggests that hepatitis C virus (HCV) plays a major role. Plasmapheresis, corticosteroids, and cytotoxic drugs have been used in the therapy of MC patients. Recently, favorable results with recombinant interferon-alpha (rIFN alpha) have been reported. To further assess its effectiveness, we studied the effects of natural human interferon-alpha (nIFN alpha), alone and in combination with 6- methyl-prednisolone (PDN), in a prospective, randomized, controlled trial in patients with symptomatic MC. Sixty-five patients were enrolled onto the trial, 52 (80%) of whom presented serum anti-HCV antibodies and specific genomic RNA sequences. Fifteen patients received nIFN alpha (3 MU) intramuscularly (IM) three times weekly, whereas 17 patients also received 16 mg/d of PDN orally on non-IFN days. Moreover, 18 patients received 16 mg/d of PDN only, and 15 were untreated. Treatment was discontinued after 1 year and patients were monitored for 8 to 17 months (mean, 13). A complete response was achieved in eight of 15 patients (53.3%) treated with nIFN alpha and nine of 17 (52.9%) treated with nIFN alpha plus PDN, as compared with three of 18 patients (16.7%) who received PDN only (P < .05) and one of 15 (6.7%) untreated controls (P < .01). Partial response occurred in two of 15 (13.3%) patients treated with nIFN alpha, three of 17 (17.6%) who received nIFN alpha plus PDN, one of 18 (5.5%) who received PDN only, and one of 15 (6.7%) controls. A complete response in six patients (66.7%) was achieved within 3 months in the group that received nIFN alpha plus PDN, as compared with two patients (25%) of those who received nIFN alpha alone (P < .02). In anti-HCV-positive patients, the clinical response occurred in step with reduced or undetectable levels of HCV RNA and transaminase normalization. Quantification of circulating HCV RNA represented a good predictive response marker. The probability of relapse within 3 months after treatment was 100% (three of three patients) and 75% (six of eight patients), respectively, in patients who received PDN alone or nIFN alpha alone as compared with none of those who received nIFN alpha plus PDN (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
85.
Telischi  M; Patel  AR; Zafar  M; Hoiberg  R 《Blood》1977,50(4):743-748
Since microaggregates have been implicated in posttransfusion pulmonary insufficiency, their elimination has become an active concern in blood transfusion. Various types of filters, as well as frozen-preserved erythrocytes, have been used to provide blood relatively low in microaggregates. We have counted particles in frozen-stored blood before deglycerolization, after washing in each of three cell processing systems, and after filtration through a 40-micrometer filter. Washing frozen erythrocytes reduced the total particle counts by an average of 89%. Slight differences were found among the three blood processors with respect to particle removal. Passing washed blood through a 40-micrometer filter did not result in significant further reduction in particle counts. Hence, the use of such filters in a frozen-preserved blood system is not warranted.  相似文献   
86.
87.
Purpose.?The aim of the study was to evaluate which factors are associated with the use of healthcare a long time after severe burn injury.

Method.?After a review process based on clinical reasoning, 69 former burn patients out of a consecutive group treated at the Uppsala Burn Unit from 1980?–?1995 were visited in their homes and their use of care and support was assessed in a semi-structured interview. Post-burn health was assessed with the Burn-Specific Health Scale-Brief (BSHS-B) and personality was assessed with the Swedish universities Scales of Personality (SSP).

Results.?The participants were injured on average eight years previously. Thirty-four had current contact with healthcare due to their burn injury and had significantly lower scores on three BSHS-B-domains: Simple Abilities, Work and Hand function, and significantly higher scores for the SSP-domain Neuroticism and the SSP-scales Stress Susceptibility, Lack of Assertiveness, and lower scores for Social Desirability. There was no relation to age, gender, time since injury, length of stay, or to the surface area burned.

Conclusions.?A routine screening of personality traits as a supplement to long-term follow-ups may help in identifying the patient's need for care.  相似文献   
88.
89.
Multiple urinary Bence-Jones proteins and serum paraproteins were found in a child with type I dysgammaglobulinaemia (Seligmann et al., 1968). These showed a continually evolving pattern over a period of 4 months in relation to systemic infections and with no evidence of underlying malignancy.  相似文献   
90.
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