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   1562篇
  免费   96篇
  国内免费   1篇
耳鼻咽喉   21篇
儿科学   49篇
妇产科学   47篇
基础医学   201篇
口腔科学   32篇
临床医学   231篇
内科学   268篇
皮肤病学   16篇
神经病学   135篇
特种医学   24篇
外科学   148篇
综合类   22篇
一般理论   1篇
预防医学   262篇
眼科学   21篇
药学   101篇
中国医学   2篇
肿瘤学   78篇
  2024年   6篇
  2023年   15篇
  2022年   13篇
  2021年   54篇
  2020年   41篇
  2019年   59篇
  2018年   54篇
  2017年   50篇
  2016年   49篇
  2015年   45篇
  2014年   59篇
  2013年   84篇
  2012年   124篇
  2011年   98篇
  2010年   72篇
  2009年   53篇
  2008年   107篇
  2007年   114篇
  2006年   107篇
  2005年   82篇
  2004年   84篇
  2003年   92篇
  2002年   71篇
  2001年   11篇
  2000年   11篇
  1999年   14篇
  1998年   10篇
  1997年   11篇
  1996年   8篇
  1995年   7篇
  1994年   6篇
  1993年   6篇
  1992年   6篇
  1991年   5篇
  1990年   3篇
  1988年   3篇
  1987年   2篇
  1986年   3篇
  1985年   2篇
  1984年   2篇
  1982年   2篇
  1981年   4篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1977年   2篇
  1976年   1篇
  1975年   1篇
  1936年   1篇
排序方式: 共有1659条查询结果,搜索用时 375 毫秒
101.
102.
103.
Sex specificity of neural mechanisms modulating nociceptive information has been demonstrated in rodents, and these qualitative sex differences appear to be relevant to analgesia from kappa-opioid receptor agonists, a drug class reported to be clinically effective only in women. Via quantitative trait locus mapping followed by a candidate gene strategy using both mutant mice and pharmacological tools, we now demonstrate that the melanocortin-1 receptor (Mc1r) gene mediates kappa-opioid analgesia in female mice only. This finding suggested that individuals with variants of the human MC1R gene, associated in our species with red hair and fair skin, might also display altered kappa-opioid analgesia. We found that women with two variant MC1R alleles displayed significantly greater analgesia from the kappa-opioid, pentazocine, than all other groups. This study demonstrates an unexpected role for the MC1R gene, verifies that pain modulation in the two sexes involves neurochemically distinct substrates, and represents an example of a direct translation of a pharmacogenetic finding from mouse to human.  相似文献   
104.
105.
Mechanisms of apoptosis induced by purine nucleosides in astrocytes   总被引:16,自引:0,他引:16  
Astrocytes release adenine-based and guanine-based purines under physiological and, particularly, pathological conditions. Thus, the aim of this study was to determine if adenosine induced apoptosis in cultured rat astrocytes. Further, if guanosine, which increases the extracellular concentration of adenosine, also induced apoptosis determined using the TUNEL and Annexin V assays. Adenosine induced apoptosis in a concentration-dependent manner up to 100 microM. Inosine, hypoxanthine, guanine, and guanosine did not. Guanosine or adenosine (100 microM) added to the culture medium was metabolized, with 35% or 15%, respectively, remaining after 2-3 h. Guanosine evoked the extracellular accumulation of adenosine, and particularly of adenine-based nucleotides. Cotreatment with EHNA and guanosine increased the extracellular accumulation of adenosine and induced apoptosis. Inhibition of the nucleoside transporters using NBTI (100 microM) or propentophylline (100 microM) significantly decreased but did not abolish the apoptosis induced by guanosine + EHNA or adenosine + EHNA, respectively. Apoptosis produced by either guanosine + EHNA or adenosine + EHNA was unaffected by A(1) or A(2) adenosine receptor antagonists, but was significantly reduced by MRS 1523, a selective A(3) adenosine receptor antagonist. Adenosine + EHNA, not guanosine + EHNA, significantly increased the intracellular concentration of S-adenosyl-L-homocysteine (SAH) and greatly reduced the ratio of S-adenosyl-L-methioine to SAH, which is associated with apoptosis. These data demonstrate that adenosine mediates apoptosis of astrocytes both, via activation of A(3) adenosine receptors and by modulating SAH hydrolase activity. Guanosine induces apoptosis by accumulating extracellular adenosine, which then acts solely via A(3) adenosine receptors.  相似文献   
106.
Results of radiotherapy for primary subglottic squamous cell carcinoma   总被引:2,自引:0,他引:2  
: To retrospectively evaluate the outcome after radical radiotherapy (RT) and surgical salvage and assess the risk of late toxicity for patients with primary subglottic squamous cell carcinoma treated at our center.

: Between 1971 and 1996, 43 patients with primary squamous cell carcinoma of the subglottis (35 men, 8 women) were treated with radical RT. All received megavoltage irradiation, most commonly to a dose of 50–52 Gy in 20 fractions during 4 weeks (39 patients). The median follow-up was 4.2 years.

: Local control was achieved with RT alone in 24 (56%) of the 43 patients: 7 of 11 with T1, 8 of 12 with T2, 4 of 8 with T3, and 5 of 12 with T4. The 5-year actuarial local relapse-free rate was 52%. Subsequent local control was achieved in 11 of the 13 patients with failed RT and attempted surgical salvage, for an ultimate local control rate of 81.4% (35 of 43). The 5-year overall and cause-specific actuarial survival rate was 50.3% and 66.9%, respectively. No patients developed Grade 3 or 4 late radiation morbidity.

: These data support the use of primary RT in the treatment of patients with primary squamous cell carcinoma of the subglottis as an appropriate treatment approach providing an option for laryngeal conservation.  相似文献   

107.
Laboratory conditions in biobehavioral experiments are commonly assumed to be ‘controlled’, having little impact on the outcome. However, recent studies have illustrated that the laboratory environment has a robust effect on behavioral traits. Given that environmental factors can interact with trait-relevant genes, some have questioned the reliability and generalizability of behavior genetic research designed to identify those genes. This problem might be alleviated by the identification of the most relevant environmental factors, but the task is hindered by the large number of factors that typically vary between and within laboratories. We used a computational approach to retrospectively identify and rank sources of variability in nociceptive responses as they occurred in a typical research laboratory over several years. A machine-learning algorithm was applied to an archival data set of 8034 independent observations of baseline thermal nociceptive sensitivity. This analysis revealed that a factor even more important than mouse genotype was the experimenter performing the test, and that nociception can be affected by many additional laboratory factors including season/humidity, cage density, time of day, sex and within-cage order of testing. The results were confirmed by linear modeling in a subset of the data, and in confirmatory experiments, in which we were able to partition the variance of this complex trait among genetic (27%), environmental (42%) and genetic×environmental (18%) sources.  相似文献   
108.
In this study, we have translated and cross-culturally adapted the Functional Assessment of Cancer Therapy-Lung (FACT-L) version 4 into Korean, and we have evaluated its reliability and validity. The FACT-L version 4 was translated into Korean following the standard Functional Assessment of Chronic Illness Therapy (FACIT) translation methodology. The psychometric properties of the FACT-L were evaluated in 122 lung cancer patients (mean age, 60.88 years). Pre-testing was performed in 22 patients, and these results indicated good content coverage and overall comprehensibility. In validating the FACT-L version 4, our results indicated high internal consistency of the FACT-L scales, with Cronbach’s α coefficients ranging from 0.52 to 0.84. The FACT-L also demonstrated good convergent and divergent validity when correlated with the Functional Living Index-Cancer (FLIC) and the shortened forms of the Profile of Mood States (POMS). This reliable and valid instrument can now be used to properly evaluate the quality of life of Korean lung cancer patients.  相似文献   
109.
Epidemiologic and genetic studies support the considerable effect of heritable factors on prostate tumorigenesis, although to date, no unequivocal susceptibility gene has been identified. The extensive study of RNASEL in prostate cancer patients worldwide has yielded conflicting results. We reevaluated the role of the RNASEL 471delAAAG Ashkenazi founder mutation in 1,642 Ashkenazi patients with prostate, bladder, breast/ovarian, and colon cancers; Ashkenazi controls; and in non-Ashkenazi prostate cancer patients and controls. The entire RNASEL coding sequence was also screened using denaturing high-performance liquid chromatography and multiplex ligation-dependent probe amplification for possible sequence variations or copy number changes in a population of prostate cancer patients. The 471delAAAG mutation was detected in 2.4% of the Ashkenazi prostate cancer patients; in 1.9% of patients with bladder, breast/ovarian, and colon cancers; and in 2.0% of the Ashkenazi controls. Seven additional variants were detected in RNASEL, including a novel potentially pathogenic splice site mutation, IVS5+1delG, although none were associated with increased prostate cancer risk. Multiplex ligation-dependent probe amplification analysis showed two RNASEL gene copies in all 300 prostate cancer patients tested. We estimated that the RNASEL 471delAAAG founder mutation, which was detected in 2% of the Ashkenazi Jews, originated between the 2nd and 5th centuries A.D., compared with the less frequent (1%) BRCA1 185delAG founder mutation, which originated hundreds of years earlier. Taken together, our analysis does not support a role for the RNASEL 471delAAAG Ashkenazi mutation nor for the other alterations detected in RNASEL in prostate cancer risk in Jewish men.  相似文献   
110.
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