全文获取类型
收费全文 | 1941篇 |
免费 | 131篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 52篇 |
儿科学 | 115篇 |
妇产科学 | 42篇 |
基础医学 | 371篇 |
口腔科学 | 8篇 |
临床医学 | 139篇 |
内科学 | 425篇 |
皮肤病学 | 42篇 |
神经病学 | 171篇 |
特种医学 | 48篇 |
外科学 | 264篇 |
综合类 | 25篇 |
一般理论 | 1篇 |
预防医学 | 129篇 |
眼科学 | 11篇 |
药学 | 121篇 |
中国医学 | 9篇 |
肿瘤学 | 119篇 |
出版年
2024年 | 3篇 |
2023年 | 17篇 |
2022年 | 18篇 |
2021年 | 43篇 |
2020年 | 19篇 |
2019年 | 48篇 |
2018年 | 51篇 |
2017年 | 35篇 |
2016年 | 39篇 |
2015年 | 37篇 |
2014年 | 57篇 |
2013年 | 79篇 |
2012年 | 141篇 |
2011年 | 170篇 |
2010年 | 94篇 |
2009年 | 83篇 |
2008年 | 130篇 |
2007年 | 132篇 |
2006年 | 146篇 |
2005年 | 120篇 |
2004年 | 139篇 |
2003年 | 109篇 |
2002年 | 96篇 |
2001年 | 24篇 |
2000年 | 25篇 |
1999年 | 25篇 |
1998年 | 21篇 |
1997年 | 22篇 |
1996年 | 18篇 |
1995年 | 19篇 |
1994年 | 16篇 |
1993年 | 18篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 13篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1974年 | 2篇 |
1971年 | 2篇 |
排序方式: 共有2092条查询结果,搜索用时 0 毫秒
41.
This article deals with the question of retiring as a test of the conjunctural resilience capacities. The continuity theory and the rupture theory are developed because their content is related to protective factors and risk factors met by retirees: the first theory advocates the use of familiar strategies in familiar areas to maintain internal and external structures. This continuity would protect mental health. The second one emphasises the gap with the working world and its affiliated status. The loss of the professional status would endanger, in a way more or less important, the subjects' mental health. Retiring, as a life event, can be experienced as a trauma or can even be compared by the subjects themselves to other significant periods of their life which have been more or less well overcome. In order to attempt to figure out the conjunctural resilience capacities requested on the first year of retirement, and at the same time, highlighting the available protective factors, two clinical vignettes of two potentially young resilient retirees are presented. 相似文献
42.
Evelyne Harkemanne Jean‐Louis Dargent Pierre‐Paul Roquet‐Gravy Audrey Bulinckx 《Pediatric dermatology》2019,36(3):365-367
We report a case of benign lymphoplasmacytic plaque (LPP) in a child. These asymptomatic erythematous papulonodular lesions are an emerging clinicopathological entity. Herein, we describe a previously unreported site for LPP lesions, namely, the volar wrist and the distal ipsilateral palm. 相似文献
43.
Hypertension in pregnancy is a frequent complication that has substantial adverse perinatal outcomes. Hypertension may be preexisting (chronic) essential or secondary hypertension; a second entity is pregnancy induced (gestational hypertension, preeclampsia). Recent advances have identified newer markers for pregnancy hypertension: several potential candidate genes may explain the apparent family inheritance of preeclampsia, and some thrombophilic markers have been associated with the condition. Management options for mild to moderate hypertension include a short hospital stay to exclude ongoing severe hypertension and to ascertain fetal well-being. Outpatient care with appropriate maternal and fetal surveillance, including umbilical artery doppler velocimetry, is recommended for better perinatal outcomes. Acute care for severe hypertension includes the use of magnesium sulfate to prevent eclampsia and antihypertensive medication. Expeditious delivery is recommended when the maternal or fetal states cannot be stabilized. Follow-up after delivery allows the uncovering of any other coexisting hypertensive or cardiovascular disorder. 相似文献
44.
Patricia Balaresque Nicolas Poulet Sylvain Cussat-Blanc Patrice Gerard Lluis Quintana-Murci Evelyne Heyer Mark A Jobling 《European journal of human genetics : EJHG》2015,23(10):1413-1422
High-frequency microsatellite haplotypes of the male-specific Y-chromosome can signal past episodes of high reproductive success of particular men and their patrilineal descendants. Previously, two examples of such successful Y-lineages have been described in Asia, both associated with Altaic-speaking pastoral nomadic societies, and putatively linked to dynasties descending, respectively, from Genghis Khan and Giocangga. Here we surveyed a total of 5321 Y-chromosomes from 127 Asian populations, including novel Y-SNP and microsatellite data on 461 Central Asian males, to ask whether additional lineage expansions could be identified. Based on the most frequent eight-microsatellite haplotypes, we objectively defined 11 descent clusters (DCs), each within a specific haplogroup, that represent likely past instances of high male reproductive success, including the two previously identified cases. Analysis of the geographical patterns and ages of these DCs and their associated cultural characteristics showed that the most successful lineages are found both among sedentary agriculturalists and pastoral nomads, and expanded between 2100 BCE and 1100 CE. However, those with recent origins in the historical period are almost exclusively found in Altaic-speaking pastoral nomadic populations, which may reflect a shift in political organisation in pastoralist economies and a greater ease of transmission of Y-chromosomes through time and space facilitated by the use of horses. 相似文献
45.
Polyomavirus infection in pediatric renal transplant recipients: evaluation using a quantitative real-time PCR technique 总被引:4,自引:0,他引:4
Herman J Van Ranst M Snoeck R Beuselinck K Lerut E Van Damme-Lombaerts R 《Pediatric transplantation》2004,8(5):485-492
Polyomavirus infection and related nephropathy is being increasingly recognized as an important cause of allograft dysfunction in adult renal transplant recipients. We prospectively monitored pediatric renal transplant recipients for the presence of BK and JC polyomavirus in urine and blood using a quantitative PCR assay to evaluate the prevalence and clinical relevance of polyomavirus infection in the pediatric renal transplant population. Of 46 pediatric renal recipients who were evaluated, nine (20%) demonstrated isolated BKV viruria, while five (11%) had concomitant BKV viremia and viruria. JCV viruria was found in eight (17%) patients. BKV viremia was associated with a significantly higher urinary BKV viral load: median urinary viral load 1.9 x 10(9) copies/mL (range 6.7 x 10(2)-1.8 x 10(11)) for the group with concomitant viremia and viruria vs. 1.8 x 10(3) copies/mL (range 2.5 x 10(2)-4.5 x 10(6)) for the group with isolated viruria (p < 0.0001). In children that were followed prospectively since their transplantation, the BKV urinary viral load increased markedly before viremia became detectable a few weeks later. None of the patients with JCV viruria or isolated BKV viruria had renal dysfunction. Among the five patients with BKV in both urine and blood, two developed biopsy-proven BKV nephropathy associated with deterioration of the renal function. Management of the BKV nephropathy consisted of reduction of immunosuppression alone or in combination with antiviral treatment with cidofovir. This study shows that polyomavirus infection and related interstitial nephritis is a relevant clinical issue in the pediatric renal transplant population. Monitoring the polyomaviral load in the urine and the blood of the patients using a quantitative PCR technique is a useful tool in the diagnosis and subsequent management of this infection. Even before viremia is present, an important rise in the urinary viral load should draw the attention of the transplant clinician and raise the issue of adapting the immunosuppression. 相似文献
46.
47.
Ogier A Franco MA Charpilienne A Cohen J Pothier P Kohli E 《European journal of immunology》2005,35(7):2122-2130
Virus-like particles containing the rotavirus (RV) internal proteins VP2 and VP6 (2/6-VLP) have been shown to induce serum and fecal antibodies as well as protection in mice after intranasal administration with a mutant of E. coli toxin, LT-R192G. To better understand the origin of fecal IgA induced by this protocol, we studied the RV-specific B cell response in systemic and mucosal lymphoid tissues using a flow cytometry assay that allows quantification and phenotypic characterization of RV-specific B lymphocytes. We also assessed the RV-specific antibody-secreting cells in the spleen and intestinal lamina propria (ILP). A remarkably high frequency of RV-specific B cells was found in the respiratory lymphoid tissues and spleen, of which only a minority expressed the alpha4beta7 integrin (intestinal homing receptor). In contrast, but in accordance with alpha4beta7 expression at the induction site, a very low response was observed in intestinal lymphoid tissues (mesenteric lymph nodes and ILP), which did not increase after a second immunization. Thus, intranasal immunization with a nonreplicating antigen does not induce an important number of RV-specific B cells with an intestinal homing profile. 相似文献
48.
Notch/Delta4 interaction in human embryonic liver CD34+ CD38- cells: positive influence on BFU-E production and LTC-IC potential maintenance 总被引:2,自引:0,他引:2
Dando JS Tavian M Catelain C Poirault S Bennaceur-Griscelli A Sainteny F Vainchenker W Péault B Lauret E 《Stem cells (Dayton, Ohio)》2005,23(4):550-560
We investigated whether Notch signaling pathways have a role in human developmental hematopoiesis. In situ histochemistry analysis revealed that Notch1, 2, and 4 and Notch ligand (Delta1-4, and Jagged1) proteins were not expressed in the yolk sac blood islands, the para-aortic splanchnopleure, the hematopoietic aortic clusters, and at the early stages of embryonic liver hematopoiesis. Notch1-2, and Delta4 were eventually detected in the embryonic liver, from 34 until 38 days postconception. Fluorescence-activated cell sorter analysis showed that first-trimester embryonic liver CD34(+)CD38(low) cells expressed both Notch1 and Notch2. When these cells were cultured on S17 stroma stably expressing Delta4, a 2.6-fold increase in BFU-E number was observed at day 7, as compared with cultures with control stroma, and this effect was maintained for 2 weeks. Importantly, exposure of these cells to Delta4 under these conditions maintained the original frequency and quality of long-term culture-initiating cells (LTC-ICs), while control cultures quickly resulted in the extinction of this LTC-IC potential. Furthermore, short-term exposure of embryonic liver adherent cells to erythropoietin resulted in a dose-dependent increase in Delta4 expression, almost doubling the expression observed with untreated stroma. This suggests that Delta4 has a role in the regulation of hematopoiesis after a hypoxic stress in the fetus. 相似文献
49.
Snoring and sleep-disordered breathing in young children: subjective and objective correlates 总被引:3,自引:0,他引:3
STUDY OBJECTIVES: We sought to assess the predictive validity of parental report of snoring and other behaviors by comparing such reports with objective findings from overnight polysomnography for the evaluation of sleep-disordered breathing in 2 nonclinical samples, namely, at-risk preschoolers and an older group reflective of the general community. Predictive validity of snoring alone and a score based on multiple child behaviors were compared to outcome at different levels of severity of sleep-disordered breathing. DESIGN: Retrospective observational study. SETTING: Questionnaires were distributed through school programs; polysomnography was performed at Kosair Children's Hospital in Louisville, Kentucky. PARTICIPANTS: One hundred twenty-two preschoolers and 172 5- to 7-year-olds, and their parents, participated in both subjective-report and objective-recording portions of the study. MEASUREMENTS AND RESULTS: Compared to the presence of snoring on polysomnography, parental report of frequent snoring was highly sensitive and specific for both age groups. At all but the lowest level of severity of sleep-disordered breathing, predictive ability was higher for both groups when a parental-report score based on multiple measures of child behavior was applied, compared to parental report of snoring alone. The profiles of these predictive child behaviors differed between the 2 groups, as did their sensitivity and specificity, at their high ranges of parental report. CONCLUSIONS: Scores derived from parental-report questionnaires of children's snoring and other sleep and wake behaviors can be used as surrogate predictors of snoring or sleep-disordered breathing in children. However, design and interpretation should consider age, risk status, and the purpose of the screening assessment. 相似文献
50.
Increased oxidative stress is associated with chronic intermittent hypoxia-mediated brain cortical neuronal cell apoptosis in a mouse model of sleep apnea 总被引:22,自引:0,他引:22
Xu W Chi L Row BW Xu R Ke Y Xu B Luo C Kheirandish L Gozal D Liu R 《Neuroscience》2004,126(2):313-323
Chronic intermittent hypoxia (CIH), as occurs in obstructive sleep apnea (SA), is associated with substantial cortico-hippocampal damage leading to impairments of neurocognitive, respiratory and cardiovascular functions. Previous studies in a rat model have shown that CIH increases brain cortical neuronal cell death. However, the molecular events leading to CIH-mediated neuronal cell death remain largely undefined. The oscillation of O2 concentrations during CIH remarkably mimics the processes of ischemia/re-oxygenation and could therefore increase cellular production of reactive oxygen species (ROS). We extended the CIH paradigm to a mouse model of SA to identify the molecular mechanisms underlying cortical neuronal cell death. A significant increase of ROS production in mouse brain cortex and cortical neuronal cells was detected by fluorescent oxidation assays upon exposure of mice to CIH, followed by increased expression of oxidative stress response markers, c-Fos, c-Jun and NF-kappaB in mouse brain cortex, as revealed by immunohistochemical and LacZ reporter assays respectively. Long-term exposure of mice to CIH increased the levels of protein oxidation, lipid peroxidation and nucleic acid oxidation in mouse brain cortex. Furthermore, exposure of mice to CIH induced caspase-3 activation and increased some cortical neuronal cell apoptosis. On the other hand, transgenic mice overexpressing Cu,Zn-superoxide dismutase exposed to CIH conditions had a lower level of steady-state ROS production and reduced neuronal apoptosis in brain cortex compared with that of normal control mice. Taken together, these findings suggest that the increased ROS production and oxidative stress propagation contribute, at least partially, to CIH-mediated cortical neuronal apoptosis and neurocognitive dysfunction. 相似文献