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   1286788篇
  免费   86976篇
  国内免费   1950篇
耳鼻咽喉   18263篇
儿科学   42363篇
妇产科学   37908篇
基础医学   187449篇
口腔科学   35470篇
临床医学   108517篇
内科学   252440篇
皮肤病学   26544篇
神经病学   99644篇
特种医学   50058篇
外国民族医学   366篇
外科学   198046篇
综合类   26562篇
现状与发展   1篇
一般理论   301篇
预防医学   92980篇
眼科学   29110篇
药学   97981篇
  18篇
中国医学   2497篇
肿瘤学   69196篇
  2018年   11888篇
  2015年   11641篇
  2014年   16066篇
  2013年   24433篇
  2012年   33687篇
  2011年   36071篇
  2010年   21283篇
  2009年   20083篇
  2008年   35091篇
  2007年   38104篇
  2006年   38662篇
  2005年   37942篇
  2004年   36506篇
  2003年   35490篇
  2002年   35016篇
  2001年   58176篇
  2000年   59676篇
  1999年   50761篇
  1998年   14259篇
  1997年   12830篇
  1996年   13096篇
  1995年   12365篇
  1994年   11772篇
  1993年   10870篇
  1992年   41038篇
  1991年   40407篇
  1990年   39928篇
  1989年   38742篇
  1988年   36156篇
  1987年   35378篇
  1986年   33752篇
  1985年   32160篇
  1984年   23960篇
  1983年   20838篇
  1982年   12387篇
  1981年   10937篇
  1980年   10225篇
  1979年   22648篇
  1978年   15903篇
  1977年   13744篇
  1976年   12981篇
  1975年   14215篇
  1974年   16710篇
  1973年   16096篇
  1972年   15336篇
  1971年   14238篇
  1970年   13237篇
  1969年   12745篇
  1968年   11987篇
  1967年   10490篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
ObjectiveThe aim was to evaluate whether laboratory automation (inoculation and automated incubation combined with timely defined high-resolution digital imaging) may help reduce the time required to obtain reliable culture analysis results.MethodsWe compared the results obtained by WASPLab automation against WASP-based automated inoculation coupled to conventional incubation and manual diagnostic on 1294 clinical samples (483 for the derivation set and 811 for the independent validation set) that included urine, genital tract and non-sterile site specimens, as well as ESwabs for screening of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive Staphylococcus aureus (MSSA), extended-spectrum beta-lactamases (ESBLs) and carbapenemase-producing Enterobacteriaceae (CPE). We used sequential routine specimens referred to the bacteriology laboratory at Geneva University Hospitals between October 2018 and March 2019.ResultsThe detection sensitivity of MRSA and MSSA at 18 hr on WASPLab was 100% (95% confidence interval [CI], 94.48–100.00%). The detection sensitivity of ESBL and CPE at 16 hr on WASPLab was 100% (95% confidence interval [CI], 94.87% to 100.00%). For urine specimens, the similarity was 79% (295/375) between 18 hr and 24 hr of incubation on WASPLab. For genital tract and non-sterile site specimens, the similarity between 16 hr and 28 hr of incubation on WASPLab were 26% (72/281) and 77% (123/159) respectively. Thus, 28 hr was defined as the final incubation time on WASPLab for genital tract and non-sterile site specimens.ConclusionsThe results of this study show that WASPLab automation enables a reduction of the culture reading time for all specimens tested without affecting performances. Implementing the established and duly validated incubation times will allow appropriate laboratory workflows for improved efficiency to be built.  相似文献   
82.
Beyond its impact on bone health, numerous studies have investigated the immune-regulatory properties of vitamin D and shown how its deficiency can affect outcomes in allogeneic hematopoietic stem cell transplantation (HSCT), particularly in acute or chronic graft-versus-host disease. This survey, carried out by the Transplant Complications Working Party of the European Society for Blood and Marrow Transplantation (EBMT), describes the current clinical practice discrepancies across the EBMT HSCT programs. We therefore recommend the development of evidence-based guidelines to standardize evaluation criteria and to harmonize the management of vitamin D deficiency in patients undergoing allogeneic HSCT.  相似文献   
83.
Purpose

Intermittent hypoxia training/treatment (IHT) is an emerging therapeutic approach to alleviate chronic diseases, such as diabetes. The present study investigated the effects of IHT on blood leucocyte pyruvate dehydrogenase kinase 1 (PDK-1) mRNA expression and its relationship with the changes in blood insulin level.

Methods

Seven adult healthy volunteers and 11 prediabetic patients participated in this study. A 3-week course of IHT consisted of a 40-min session of 4 cycles of 5-min 12% O2 and 5-min room air breathing per day, 3 sessions per week for 3 weeks (i.e., total 9 sessions of IHT). Plasma insulin levels and leukocyte PDK-1 mRNA expression were determined at various time points either under fasting condition or following oral glucose tolerance test (OGTT). Correlation between the IHT-induced changes in PDK-1 mRNA and insulin or glucose levels in the same serological samples was analyzed.

Results

At pre-IHT baseline, PDK-1 mRNA expression was two times higher in prediabetes than control subjects. IHT resulted in significant augmentation in PDK-1 mRNA expression (> twofold) in prediabetes at the end of 3-week IHT and remained elevated 1 month after IHT, which was correlated with a significantly reduced insulin release and lower blood glucose after glucose loading with OGTT.

Conclusion

IHT can trigger beneficial effects in normalizing blood insulin levels in prediabetic patients under oral glucose load, which were closely correlated with an enhanced mRNA expression of PDK-1 in leukocytes. Further clinical trials are warranted to validate the utility of IHT as a non-invasive complementary therapy against diabetes-associated pathologies.

  相似文献   
84.
85.
86.
87.
The anti-epileptic drugs phenobarbital and valproic acid have an extremely strong negative effect on cognitive processes such as learning and memory in the developing brain. We examined whether or not curcumin has protective effects on neuronal injury caused by these drugs in the developing rat brain. Young male Wistar rats were studied in two groups, a 7 days old and a 14 days old group (35 rats in each). Both groups were then divided into 7 sub-groups as the control, curcumin, dimethylsulfoxide, phenobarbital, valproic acid, phenobarbital + curcumin, and valproic acid + curcumin groups (n = 5 in each group). At 24 h after the intraperitoneal injection of the compounds, the rats were sacrificed, and the hippocampal tissue was subjected to stereological analysis with the optical fractionation method. Total numbers of neurons in the hippocampus of the 7 days old and 14 days old rats were calculated. It was found that treatment with phenobarbital resulted in a loss of 43% of the neurons, and valproic acid induced a loss of 57% of the neurons in the 7 days old rats. Curcumin prevented this loss significantly with only 19% in the phenobarbital group and 41% in the valproic acid group. In the 14 days old rat groups, phenobarbital was found to reduce the number of neurons by 30%, and valproic acid reduced it by 38%. Curcumin treatment limited neuronal loss to 3% in the phenobarbital + curcumin group and 10% in the valproic acid + curcumin group. These data strongly indicate that curcumin is a protective agent and prevents hippocampal neuronal damage induced by phenobarbital and valproic acid treatment.  相似文献   
88.
AimTo investigate clinico-pathological features of lymphoma of the lips, and review the literature.Materials and MethodsRetrospective analysis and review of English literature, 1996-2016.ResultsAnalysis included 23 cases, 7 new cases and 16 from literature, 12 M: 11 F, age 7–82 years. Four occurred in children, mean age 10.1; 19 in adults, mean 61.1 years.The lower lip was involved in the majority of cases (16, 69.56%). 14 (60.87%) were isolated to the lips, 8 (34.78%) were multifocal. Nine (39.13%) occurred in association with Sjogren's syndrome, of which one also had Hashimoto thyroiditis. IgG4-related disease and HIV were reported in one case each. The lip salivary glands were involved in most cases (19, 82.6%); 3 (13.6%) showed only cutaneous involvement.The typical presentation was single or multiple nodules (15, 65.21%), with surface ulceration in only two (8.69%). Constituent symptoms were absent in all cases, paresthesia was reported in one (4.34%). The majority (18, 78.26%) was extranodal marginal zone B-cell lymphoma - mucosa-associated lymphoid tissue lymphoma (EMZB-MALT), and one case each was mantle cell, NK-T cell, CD30 positive and plasmablastic lymphoma.ConclusionThe lips seem to have a unique pattern of non-Hodgkin lymphoma dominated by EMZB-MALT lymphoma, rarely other types. In more than half, neither Sjogren's syndrome nor other chronic inflammation was identified. Lesions tend to present as asymptomatic slowly progressing, non-ulcerated submucosal masses. Lymphoma should be considered even in the absence of constituent symptoms, as most cases showed none. Although the number of reported cases is rather small, disease course is usually prolonged and prognosis seems to be good.  相似文献   
89.
90.
Neuroscience and Behavioral Physiology - We report here a comparative (using chemical, electrical, and optical stimulation) study of the electrophysiological properties of cultured hippocampal...  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