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   869篇
  免费   74篇
  国内免费   2篇
耳鼻咽喉   42篇
儿科学   44篇
妇产科学   1篇
基础医学   178篇
口腔科学   17篇
临床医学   77篇
内科学   134篇
皮肤病学   27篇
神经病学   43篇
特种医学   73篇
外科学   89篇
综合类   16篇
预防医学   58篇
眼科学   60篇
药学   39篇
中国医学   1篇
肿瘤学   46篇
  2022年   4篇
  2020年   6篇
  2019年   8篇
  2018年   14篇
  2017年   13篇
  2016年   9篇
  2015年   19篇
  2014年   30篇
  2013年   31篇
  2012年   50篇
  2011年   35篇
  2010年   29篇
  2009年   38篇
  2008年   30篇
  2007年   25篇
  2006年   34篇
  2005年   25篇
  2004年   25篇
  2003年   21篇
  2002年   22篇
  2001年   38篇
  2000年   18篇
  1999年   14篇
  1998年   27篇
  1997年   31篇
  1996年   31篇
  1995年   19篇
  1994年   30篇
  1993年   18篇
  1992年   15篇
  1991年   19篇
  1990年   9篇
  1989年   18篇
  1988年   12篇
  1987年   13篇
  1986年   12篇
  1985年   20篇
  1984年   8篇
  1983年   10篇
  1982年   8篇
  1981年   8篇
  1980年   10篇
  1979年   8篇
  1978年   7篇
  1977年   7篇
  1976年   15篇
  1975年   5篇
  1974年   9篇
  1971年   4篇
  1968年   6篇
排序方式: 共有945条查询结果,搜索用时 15 毫秒
31.
32.
Six young women who had taken progestational agents for a period of time ranging from six months to five years developed symptoms and signs of pulmonary hypertension. Cardiac catheterization confirmed the presence of severe pulmonary hypertension without evidence of other cardiac or pulmonary abnormalities to explain this phenomenon. Three of the patients had potential predispositions to pulmonary hypertension, including a corrected patent ductus arteriosus with mild pulmonary hypertension in one, collagen vascular disease in a second, and family history of pulmonary hypertension in a third. Three patients had no known predisposing factors. Although the relationship between oral contraceptives and severe pulmonary hypertension is problematic, there have been isolated reports of cases of pulmonary hypertension secondary to oral contraceptive usage. These cases and the possible pathophysiologic mechanisms responsible are discussed.  相似文献   
33.
71 patients admitted to Newcastle Regional Neurosurgical Centre between 1979 and 1988 with a diagnosis of brain abscess are reviewed. The overall mortality was 9.9%, with an operative mortality of 7%. The bacteriology of these abscesses is discussed in detail, together with the importance of effective standardized antimicrobial treatment regimens. The low mortality figures appeared to be in direct relationship to early recognition of this condition, prompt surgical intervention and effective chemotherapy.  相似文献   
34.
Metal hip replacements generate both metal particles and ions. The biological effects of peri-articular exposure to nanometre and micron sized cobalt chrome (CoCr) wear particles were investigated in a mouse model. Mice received injections of two clinically relevant doses of nanoparticles (32 nm), one of micron sized (2.9 μm) CoCr particles or vehicle alone into the right knee joint at 0, 6, 12 and 18 weeks. Mice were analysed for genotoxic and immunological effects 1, 4 and 40 weeks post exposure. Nanoparticles but not micron particles progressively corroded at the injection site. Micron sized particles were physically removed. No increase of Co or Cr was seen in peripheral blood between 1 and 40 weeks post exposure to particles. No significant inflammatory changes were observed in the knee tissues including ALVAL or necrosis. DNA damage was increased in bone marrow at one and forty weeks and in cells isolated from frontal cortex at 40 weeks after injection with nanoparticles. Mice exposed to the micron sized, but not nanoparticles became immunologically sensitized to Cr(III), Cr (VI) and Ni(II) over the 40 week period as determined by lymphocyte transformation and ELISpot (IFN-γ and IL-2) assays. The data indicated that the response to the micron sized particles was Th1 driven, indicative of type IV hypersensitivity. This study adds to understanding of the potential adverse biological reactions to metal wear products.  相似文献   
35.
BRCA1 and BRCA2 are major breast cancer susceptibility genes. Nineteen single nucleotide polymorphisms (SNPs) at 18 loci have been associated with breast cancer. We aimed to determine whether these predict breast cancer incidence in women with BRCA1/BRCA2 mutations. BRCA1/2 mutation carriers identified through the Manchester genetics centre between 1996 and 2011 were included. Using published odds ratios (OR) and risk allele frequencies, we calculated an overall breast cancer risk SNP score (OBRS) for each woman. The relationship between OBRS and age at breast cancer onset was investigated using the Cox proportional hazards model, and predictive ability assessed using Harrell's C concordance statistic. In BRCA1 mutation carriers we found no association between OBRS and age at breast cancer onset: OR for the lowest risk quintile compared to the highest was 1.20 (95% CI 0.82–1.75, Harrell's C = 0.54), but in BRCA2 mutation carriers the association was significant (OR for the lowest risk quintile relative to the highest was 0.47 (95% CI 0.33–0.69, Harrell's C = 0.59). The 18 validated breast cancer SNPs differentiate breast cancer risks between women with BRCA2 mutations, but not BRCA1. It may now be appropriate to use these SNPs to help women with BRCA2 mutations make maximally informed decisions about management options.  相似文献   
36.
We have previously shown that normal-density human peripheral blood eosinophils transcribe and translate mRNA for granulocyte-macrophage colony-stimulating factor (GM-CSF) and that the intracellular distribution was granular as assessed by light microscopy immunocytochemistry. The present study was conducted to confirm this apparent association between GM-CSF and the crystalloid granule using a subcellular fractionation method for human eosinophils and immunogold electron microscopy (EM). Highly purified (> 99%, by negative selection using anti-CD16 immunomagnetic microbeads) human peripheral blood eosinophils were obtained from four asthmatic subjects (not taking systemic medication), homogenized and density fractionated (5 x 10(7) cells/subject) on linear Nycodenz gradients. Twenty-four fractions were collected from each cell preparation and analyzed for marker enzyme activities as well as total protein. Dot blot analysis with specific monoclonal antibodies (MoAbs) was used to detect the eosinophil granule proteins major basic protein (MBP) and eosinophil cationic protein (ECP). An anti-CD9 MoAb was used as an eosinophil plasma membrane marker. Lactate dehydrogenase (LDH) was used as a cytosolic marker. Immunoreactivity for GM-CSF was detected by a specific enzyme-linked immunosorbent assay using a polyclonal antihuman GM-CSF antibody and confirmed by dot blot. GM-CSF coeluted with the cellular fractions containing granule markers (MBP, ECP, eosinophil peroxidase, hexosaminidase, and arylsulphatase), but not those containing cytoplasm (LDH+) or membrane (CD9+) markers. EM examination of pooled fractions associated with the peak of GM-CSF immunoreactivity confirmed that they contained crystalloid and small granules, but not plasma membrane. In addition, quantification, using immunogold labeling with an anti/GM-CSF MoAb, indicated preferential localization of gold particles over the eosinophil granule cores of intact cells. Thus, our results indicate that GM-CSF resides as a granule-associated, stored mediator in unstimulated human eosinophils.  相似文献   
37.
The present article reports a case involving an immunocompetent, previously well child who, despite two previous doses of inactivated poliovirus vaccine, developed severe flaccid paralysis consistent with polio after receiving oral polio vaccine.  相似文献   
38.

Background

Uncertainty remains as to the role of decompressive craniectomy (DC) for primary evacuation of an acute subdural haematoma (ASDH). In 2011, a collaborative group of neurosurgeons, neuro-intensive care physicians and trial methodologists was formed in the UK with the aim of answering the following question: “What is the clinical- and cost-effectiveness of DC, in comparison to simple craniotomy for adult patients undergoing primary evacuation of an ASDH?” The proposed RESCUE-ASDH trial (Randomised Evaluation of Surgery with Craniectomy for patients Undergoing Evacuation of Acute Subdural Haematoma) is a multi-centre, pragmatic, parallel group randomised trial of DC versus simple craniotomy for adult head-injured patients with an ASDH. Clinical trials in the emergency setting face the problem that potential participants may be incapacitated and their next of kin initially unavailable. As a result, consent and enrolment of participants can often be difficult.

Method

In the current study, we aimed to assess public opinion regarding participation in the RESCUE-ASDH trial and acceptability of surrogate consent by conducting a pre-protocol community consultation survey.

Results

One hundred and seventy-one subjects completed the survey. Eighty-four percent of participants responded positively when asked if they would participate in the proposed trial. Ninety-six percent and 91 % answered positively when asked if they found surrogate consent by their next of kin and an independent doctor acceptable, respectively. None of the characteristics of the study population were found to affect the decision to participate or the acceptability of surrogate consent by the next of kin. Being religious showed a trend towards higher acceptability of surrogate consent by a doctor. Conversely, an education to degree level and above showed a trend towards reduced acceptability of surrogate consent by a doctor.

Conclusions

Our community consultation survey shows that the proposed trial is acceptable to the public. In addition, the results suggest high levels of acceptability of surrogate consent by next of kin or independent doctor amongst our community.  相似文献   
39.
40.

Distress caused by sensory processing differences for autistic individuals may be reduced by repetitive behaviours (RRB), including repetitive motor (RMB) and insistence on sameness (ISB) behaviours. Intolerance of uncertainty (IU) and anxiety mediate the relationship between sensory processing and RRB in autistic children. We replicated this model in autistic adults, extending it to include alexithymia. Serial mediation, using data from 426 autistic adults, identified significant direct effects from sensory processing to RMB and ISB, and indirect effects through alexithymia-IU-anxiety for RMB, and IU alone, and alexithymia-IU for ISB. Different mechanisms may underpin RMB and ISB. Alexithymia alongside, IU and anxiety, should be considered when understanding the relationship between sensory processing and RRB, and when offering interventions to support autistic people.

  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