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   1854篇
  免费   120篇
  国内免费   37篇
耳鼻咽喉   45篇
儿科学   54篇
妇产科学   91篇
基础医学   166篇
口腔科学   457篇
临床医学   90篇
内科学   210篇
皮肤病学   14篇
神经病学   69篇
特种医学   48篇
外科学   221篇
综合类   209篇
预防医学   133篇
眼科学   137篇
药学   38篇
  1篇
中国医学   7篇
肿瘤学   21篇
  2023年   32篇
  2022年   67篇
  2021年   81篇
  2020年   83篇
  2019年   73篇
  2018年   85篇
  2017年   68篇
  2016年   67篇
  2015年   68篇
  2014年   124篇
  2013年   132篇
  2012年   102篇
  2011年   110篇
  2010年   81篇
  2009年   86篇
  2008年   87篇
  2007年   70篇
  2006年   64篇
  2005年   58篇
  2004年   67篇
  2003年   53篇
  2002年   48篇
  2001年   27篇
  2000年   22篇
  1999年   34篇
  1998年   39篇
  1997年   32篇
  1996年   13篇
  1995年   20篇
  1994年   14篇
  1993年   14篇
  1992年   18篇
  1991年   17篇
  1990年   3篇
  1989年   5篇
  1988年   3篇
  1987年   6篇
  1986年   5篇
  1985年   5篇
  1984年   9篇
  1983年   4篇
  1982年   2篇
  1981年   3篇
  1980年   4篇
  1979年   2篇
  1978年   3篇
  1976年   1篇
排序方式: 共有2011条查询结果,搜索用时 15 毫秒
51.
52.
BackgroundAssessing the role of HIV and non-HIV related factors is essential for a better understanding of the neurocognitive outcomes in perinatally HIV-infected (PHIV+) young people. The aim of our study was to assess cognition and quality of life (QoL) of a PHIV+ cohort of young people and to compare it with a control group.MethodsThirty PHIV+ and 30 HIV(−) healthy young adults matched by age, sex and socioeconomic status completed a protocol that included neurocognitive tests, a psychosocial semi-structured interview and a QoL questionnaire (PedsQL). Neurocognitive domain-specific and domain-general (NPZ-5) Z-scores were calculated. CDC AIDS-defining category C or not C (PHIV+/C, PHIV+/noC) was considered to evaluate differences within the PHIV+ group. Univariate and multivariate analysis were performed.ResultsSixty patients were included; 67% were female; median age (IQR) 19 years (18–21). Regarding PHIV+ young people, 27% showed CDC C category (none encephalopathy), 93% were on ART and 77% had undetectable viral load. No differences regarding occupation were found, although the HIV(−) group repeated less grades (p = 0.028) and had a higher education level (p = 0.021).No differences were found between PHIV+/noC and HIV(−) participants. However, the PHIV+/C group showed poorer performance than PHIV+/noC (NPZ-5, p = 0.037) and HIV(−) subjects (crystallised intelligence, p = 0.025; intelligence quotient, p = 0.016). Higher nadir CD4+ T-cell count was related to better Z-score in memory (p = 0.007) and NPZ-5 (p = 0.025). Earlier and longer exposure to ART resulted in better performance in memory (p = 0.004) and executive functions (p = 0.015), respectively.ConclusionsNo significant differences were found in the neurocognitive profile nor QoL between PHIV+/noC and HIV(−) adolescents; however, PHIV+/C participants obtained lower scores. The use of longer and earlier ART seems to have a beneficial effect.  相似文献   
53.
We know of no universally accepted classification for intracapsular condylar fractures. We propose here a new classification based on the concept of a “disc-condyle” unit, and validate the classification based on outcomes of treatment. From 1 January 2010 - 31 December 2014, 55 patients with unilateral intracapsular condylar fractures were classified into three types: type A has no reduction in mandibular height or displacement of the disc (n = 7); type B has displacement of the disc with no reduction in mandibular height (n = 17); and type C has reduced mandibular height with or without displacement of the disc (n = 31). We treated types B and C by open reduction and fixation, while type A fractures were managed non-surgically. At six month follow-up, we found no significant differences in the vertical height of the ramus, mandibular deviation, protrusion, or lateral protrusion between the fractured and healthy sides. All patients had normal occlusion postoperatively and only one patient (type C) reported pain. Magnetic resonance imaging and computed tomography showed good osseous healing and disc-condylar relations in all cases. Our results show that this new classification of intracapsular condylar fractures is a safe and easy way to obtain satisfactory outcomes of treatment. However, it needs further independent validation.  相似文献   
54.
55.
Epigenetic mechanisms participate in melanoma development and progression. The effect of histone modifications and their catalysing enzymes over euchromatic promoter DNA methylation in melanoma remains unclear. This study investigated the potential association of p16INK4A promoter methylation with histone methyltransferase SETDB1 expression in Greek patients with sporadic melanoma and their correlation with clinicopathological characteristics. Promoter methylation was detected by methylation‐specific PCR in 100 peripheral blood samples and 58 melanoma tissues from the same patients. Cell proliferation (Ki‐67 index), p16INK4A and SETDB1 expression were evaluated by immunohistochemistry. High‐frequency promoter methylation (25.86%) was observed in tissue samples and correlated with increased cell proliferation (= 0.0514). p16INK4A promoter methylation was higher in vertical growth‐phase (60%) melanomas than in radial (40%, = 0.063) and those displaying epidermal involvement (= 0.046). Importantly, p16INK4A methylation correlated with increased melanoma thickness according to Breslow index (= 0.0495) and marginally with increased Clark level (I/II vs III/IV/V, = 0.070). Low (1–30%) p16INK4A expression was detected at the majority (19 of 54) of melanoma cases (35.19%), being marginally correlated with tumor lymphocytic infiltration (= 0.078). SETDB1 nuclear immunoreactivity was observed in 47 of 57 (82.46%) cases, whereas 27 of 57 (47.37%) showed cytoplasmic immunoexpression. Cytoplasmic SETDB1 expression correlated with higher frequency of p16INK4A methylation and p16INK4A expression (= 0.033, = 0.011, respectively). Increased nuclear SETDB1 levels were associated with higher mitotic count (0–5/mm2 vs >5/mm2, = 0.0869), advanced Clark level (III‐V, = 0.0380), epidermal involvement (= 0.0331) and the non‐chronic sun exposure‐associated melanoma type (= 0.0664). Our data demonstrate for the first time the association of histone methyltransferase SETDB1 with frequent methylation of the euchromatic p16INK4A promoter and several prognostic parameters in melanomas.  相似文献   
56.
Vertical gaze palsy is rarely a neurological symptom, although it has been observed in some cases. Here, we report the case of a patient presenting with complete upward and downward gaze palsy. In this case, a small lesion in the left rostral midbrain was observed on diffusion-weighted magnetic resonance (MR) images, and the lesion was considered to cause the ocular symptom. We consider that vertical gaze palsy is an important clue to an accurate topical diagnosis of a brain lesion.  相似文献   
57.
《Acta oto-laryngologica》2012,132(6):587-593
Conclusions. Subjective visual vertical (SVV) estimation during on-axis rotation provides an efficient screening test of utricle function. The survey demonstrates that isolated disorders of peripheral utricular function can occur while SCC function appears normal. Objective. The present study aimed to investigate estimation of SVV during constant velocity yaw rotation (with the head held on-axis – to enhance any asymmetry between right and left utricular responses), as a useful screening test. Materials and methods. In all, 230 patients were recruited from the dizziness clinic. For each patient, the SVV was estimated (a) while held stationary, and (b) during constant angular velocity (240°/s), with the head centred on-axis. Bithermal caloric testing was also performed in 201 of the patients. Results. Of those patients with normal SVV results during stationary testing, 18.3% were pathological during rotation testing. In those cases with pathological SVV during stationary testing, a significantly greater deviation from the norm was observed during rotation (p<0.001). Of those patients with normal caloric responses, 44.4% showed pathological SVV estimates; this increased to 54.3% for cases with unilateral weakness, and 56.5% for unilateral loss. No clear correlation was found between reports of tilt illusion and pathological SVV, respectively, between rotatory vertigo and pathological caloric responses.  相似文献   
58.
59.
60.
Two patients, a daughter and her father, developed the acute type of adult T-cell leukemia/lymphoma (ATLL) within a 3-month period. Antibodies against HTLV-I have been found in both wives of the father. The second wife acquired the infection from her husband within 3 years of marriage. The patients described represent the first cases of familial ATLL in the United States. ATLL continues to be frequently misdiagnosed in the United States. A positive family history consistent with this disease in a patient with a lymphoid malignancy may be a helpful clue for earlier diagnosis.  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