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   22299篇
  免费   1762篇
  国内免费   49篇
耳鼻咽喉   300篇
儿科学   766篇
妇产科学   677篇
基础医学   3060篇
口腔科学   236篇
临床医学   2567篇
内科学   4225篇
皮肤病学   366篇
神经病学   2480篇
特种医学   632篇
外国民族医学   5篇
外科学   2556篇
综合类   231篇
一般理论   16篇
预防医学   2521篇
眼科学   344篇
药学   1347篇
中国医学   14篇
肿瘤学   1767篇
  2023年   254篇
  2022年   472篇
  2021年   869篇
  2020年   466篇
  2019年   832篇
  2018年   930篇
  2017年   636篇
  2016年   685篇
  2015年   747篇
  2014年   1002篇
  2013年   1171篇
  2012年   1792篇
  2011年   1813篇
  2010年   893篇
  2009年   773篇
  2008年   1282篇
  2007年   1291篇
  2006年   1159篇
  2005年   1118篇
  2004年   1015篇
  2003年   817篇
  2002年   754篇
  2001年   213篇
  2000年   227篇
  1999年   183篇
  1998年   193篇
  1997年   132篇
  1996年   116篇
  1995年   90篇
  1994年   81篇
  1993年   70篇
  1992年   148篇
  1991年   146篇
  1990年   126篇
  1989年   124篇
  1988年   115篇
  1987年   112篇
  1986年   120篇
  1985年   94篇
  1984年   95篇
  1983年   74篇
  1982年   48篇
  1981年   52篇
  1979年   65篇
  1978年   50篇
  1977年   47篇
  1976年   49篇
  1974年   59篇
  1973年   54篇
  1971年   48篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
BACKGROUND: The assessment of perinatal depressions and coping style. Methods: With depression scales (EPDS, GHQ.12) and Carver's BriefCope, the authors compared the prevalence rates of pre and postnatal depression in a cohort of 277 French women. RESULTS: Their work revealed very high levels of prenatal depression (almost 20%) and less important but nonetheless sizeable rates (11%) of postnatal depression, making such perinatal depressions a major public health concern. The coping styles proposed in Carver's public health BriefCope questionnaire make it possible to significantly differentiate during these two periods between depressive women and their non-depressed counterparts. CONCLUSIONS: This enables us to underline factors of risk and protection suggesting the importance of setting up compensatory and preventive systems and evaluating their pertinence in the framework of future research.  相似文献   
62.
Assessing the effects of bupropion SR on mood dimensions of depression   总被引:13,自引:0,他引:13  
BACKGROUND: We assessed the therapeutic effects of bupropion SR and placebo on mood and anxiety symptoms derived from the tripartite model of mood. Based on evidence indicating linkages between dopaminergic activity and the emotional dimension of positive affect/anhedonia, we hypothesized that the dopaminergic effects of bupropion SR would yield particularly pronounced effects on symptoms of anhedonia, relative to anxiety. METHODS: Nineteen depressed outpatients were randomly assigned to treatment with either bupropion SR 300 mg/day or placebo during a 6-week initial treatment phase. This was followed by a second open-label phase in which patients previously treated with bupropion SR had their dose increased to 400 mg/day, and the placebo group was initiated on bupropion SR 300 mg/day. RESULTS: Random regression analyses revealed that during the initial double-blind phase, bupropion SR elicited greater declines than placebo on all measures except those that assessed anxiety. By contrast, the weakest placebo effects were evident on anhedonia. Items assessing the low positive affect pole of the anhedonia dimension were more sensitive to earlier/lower dose bupropion SR treatment, whereas items assessing the high positive affect pole were more sensitive to later/higher dose bupropion SR treatment. LIMITATIONS: Replication and extension using a larger sample size are mandated. CONCLUSIONS: This study suggests that the catecholaminergic effects of bupropion SR tended to produce more robust effects on anhedonia/positive affect than placebo.  相似文献   
63.
A sound that we hear in a natural setting allows us to identify the sound source and localize it in space. The two aspects can be disrupted independently as shown in a study of 15 patients with focal right-hemispheric lesions. Four patients were normal in sound recognition but severely impaired in sound localization, whereas three other patients had difficulties in recognizing sounds but localized them well. The lesions involved the inferior parietal and frontal cortices, and the superior temporal gyrus in patients with selective sound localization deficit; and the temporal pole and anterior part of the fusiform, inferior and middle temporal gyri in patients with selective recognition deficit. These results suggest separate cortical processing pathways for auditory recognition and localization. Electronic Publication  相似文献   
64.
65.
A fetus with lobar holoprosencephaly and lumbosacral meningomyelocele associated with duplication of the short arm of chromosome 3 is reported. The anomalies were detected on fetal ultrasound at 20 weeks' gestation and the autopsy findings correlated well with the prenatal findings. The fetal karyotype was 46,XY,der(3)del(3)(p26) dup(3)(p26p21.3). The association of holoprosencephaly with duplication 3p is well known, but to the best of our knowledge this is the first reported association of meningomyelocele with 3p duplication. These findings suggest that a gene or genes with a crucial role in central nervous system development are located on the short arm of chromosome 3.  相似文献   
66.
Primed and unprimed lymphocytes are usually classified as separate subsets of cells, based on phenotypic and functional distinctions. In the case of CD4+ T lymphocytes, primed cells are thought to proliferate more vigorously, quickly and easily, and to release a different profile of cytokines, than their naive equivalent. However, most of these data were obtained from studies in which populations of lymphocytes were compared before and after antigenic stimulation, and therefore did not distinguish between the effects resulting from the clonal expansion of specific precursor cells within such populations and those due to cell differentiation per se. We have investigated the contribution of precursor cell frequency to some of the functional changes observed in populations of CD4+ T cells following antigenic stimulation, using approaches in which antigen-specific precursor frequencies are high in both primary and secondary stimulations: mixed leukocyte reaction responses and cells from αβ T cell receptor transgenic mice. Our data suggest that when equivalent numbers of antigen-specific naive and previously primed CD4+ responder T cells are compared, there is no difference in their potency to proliferate but only the previously activated subset can generate cytokines such as interferon-γ.  相似文献   
67.
68.
The efficacy of problem-solving therapy (PST) to reduce psychological distress was assessed among a sample of 132 adult cancer patients. A second condition provided PST for both the patient and a significant other. At posttreatment, all participants receiving PST fared significantly better than waiting list control patients. Further, improvements in problem solving were found to correlate significantly with improvements in psychological distress and overall quality of life. No differences in symptom reduction were identified between the 2 treatment protocols. At a 6-month follow-up, however, patients who received PST along with their significant other reported lower levels of psychological distress as compared with members of the PST-alone condition on approximately half of the outcome measures. These effects were further maintained 1-year posttreatment.  相似文献   
69.
Apoptosis of dentate granule cells is a typical feature of several animal models of disease. In 20 autopsy cases of subarachnoid hemorrhage (SAH) and global cerebral hypoxia caused by protracted shock or respiratory failure, we evaluated by light microscopy and in situ tailing whether this pattern of neuronal damage also occurs in humans. In subarachnoid hemorrhage, 4.0/mm2 (0-13.0/mm2) apoptotic neurons were observed in the dentate gyrus, in cerebral hypoxia 3.6/mm2 (0-19.9/mm2) (p>0.05), and in 10 aged-matched control cases dying rapidly from non-neurological diseases 0/mm2 (0-0/mm2) (median [range]) (p<0.001 versus SAH and hypoxia). Neuronal apoptosis in the dentate gyrus was most frequent, when death occurred later than 24 hours and less than 11 days after disease onset. Neuronal damage in the hippocampus was always necrotic. It was more severe in hypoxia than in SAH (median neuronal damage score 3 [range: 0-3] versus 0 [0-3], p<0.001). Apoptosis appears to be the predominant mechanism of death in dentate granule cells irrespective of the underlying disease, whereas neuronal death in the hippocampus generally is of necrotic morphology.  相似文献   
70.
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