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   3914篇
  免费   186篇
  国内免费   15篇
耳鼻咽喉   80篇
儿科学   89篇
妇产科学   53篇
基础医学   578篇
口腔科学   36篇
临床医学   402篇
内科学   807篇
皮肤病学   67篇
神经病学   370篇
特种医学   161篇
外国民族医学   4篇
外科学   651篇
综合类   21篇
一般理论   3篇
预防医学   211篇
眼科学   24篇
药学   270篇
中国医学   2篇
肿瘤学   286篇
  2023年   14篇
  2022年   29篇
  2021年   87篇
  2020年   29篇
  2019年   71篇
  2018年   103篇
  2017年   41篇
  2016年   57篇
  2015年   86篇
  2014年   110篇
  2013年   155篇
  2012年   292篇
  2011年   326篇
  2010年   159篇
  2009年   163篇
  2008年   251篇
  2007年   235篇
  2006年   250篇
  2005年   221篇
  2004年   181篇
  2003年   204篇
  2002年   160篇
  2001年   90篇
  2000年   75篇
  1999年   76篇
  1998年   44篇
  1997年   30篇
  1996年   33篇
  1995年   18篇
  1994年   21篇
  1993年   30篇
  1992年   50篇
  1991年   29篇
  1990年   31篇
  1989年   35篇
  1988年   28篇
  1987年   32篇
  1986年   37篇
  1985年   25篇
  1984年   22篇
  1983年   22篇
  1982年   16篇
  1979年   15篇
  1978年   15篇
  1976年   8篇
  1973年   8篇
  1972年   11篇
  1970年   8篇
  1966年   10篇
  1965年   8篇
排序方式: 共有4115条查询结果,搜索用时 242 毫秒
71.
72.
The optimal method to assess the adequacy of peritoneal dialysis therapies is controversial. Today, the adequacy must not be considered as a number or a concept assessed only by two parameters (total KT/V urea and total solute clearance) but defined by many more items. In the absence of data, based on theoretical considerations, the reanalysis of the CANUSA study showed that renal kidney function, rather than peritoneal clearance, was associated with improved survival. Residual renal function is considered as a major predictor factor of cardiovascular mortality. Results of this reanalysis were supported by the adequacy data in ADEMEX, EAPOS and ANZDATA studies. Therefore, clinical assessment plays a major role in PD adequacy. The management of fluid balance, the regular monitoring of malnutrition, the control of mineral metabolism and particularly the glucose load, considered as the “corner-stone” of the system, are the main points to be considered in the adequacy of PD patients. The essential goal is to minimize glucose load by glucose-sparing strategies in order to reduce the neoangiogenesis of the peritoneal membrane.  相似文献   
73.

Chronic granulomatous disease (CGD) is an inherited immunodeficiency due to defective leukocyte NADPH responsible for recurrent infections and aberrant inflammation. Mutations in the CYBB gene are responsible for the X-linked CGD and account for approximately 70% of the cases. CGD is diagnosed during childhood in males. Female carriers may have biased X-inactivation and may present with clinical manifestations depending on the level of residual NADPH oxidase activity. We report the case of a previously asymptomatic female carrier who was diagnosed at age 67 with a skin infection with the rare fungus Paecilomyces lilacinus as the first manifestation of CGD. Dihydrorhodamine 123 (DHR) activity was below 10%. Next-generation sequencing (NGS) revealed mutations in DNMT3A, ASXL1, and STAG2 suggesting that clonal hematopoiesis could be responsible for a progressive loss of NADPH oxidase activity and the late onset of X-linked CGD in this patient. Long-term follow-up of asymptomatic carrier women seems to be essential after 50 years old.

  相似文献   
74.
The neonatal gut is rapidly colonized by a newly dominant group of commensal Escherichia coli strains among which a large proportion produces a genotoxin called colibactin. In order to analyze the short- and long-term effects resulting from such evolution, we developed a rat model mimicking the natural transmission of E. coli from mothers to neonates. Genotoxic and non-genotoxic E. coli strains were equally transmitted to the offspring and stably colonized the gut across generations. DNA damage was only detected in neonates colonized with genotoxic E. coli strains. Signs of genotoxic stress such as anaphase bridges, higher occurrence of crypt fission and accelerated renewal of the mature epithelium were detected at adulthood. In addition, we observed alterations of secretory cell populations and gut epithelial barrier. Our findings illustrate how critical is the genotype of E. coli strains acquired at birth for gut homeostasis at adulthood.  相似文献   
75.
Variant Creutzfeldt-Jakob disease (vCJD) has been reported in 12 countries. We hypothesized that a common strain of agent is responsible for all vCJD cases, regardless of geographic origin. To test this hypothesis, we inoculated strain-typing panels of wild-type mice with brain material from human vCJD case-patients from France, the Netherlands, Italy, and the United States. Mice were assessed for clinical disease, neuropathologic changes, and glycoform profile; results were compared with those for 2 reference vCJD cases from the United Kingdom. Transmission to mice occurred from each sample tested, and data were similar between non-UK and UK cases, with the exception of the ranking of mean clinical incubation times of mouse lines. These findings support the hypothesis that a single strain of infectious agent is responsible for all vCJD infections. However, differences in incubation times require further subpassage in mice to establish any true differences in strain properties between cases.  相似文献   
76.
International Urology and Nephrology - The optimal vitamin D3 therapy for the treatment of secondary hyperparathyroidism (SHPT) in chronic hemodialysis patients is still controversial. Recent...  相似文献   
77.
OBJECTIVE: Percutaneous endoscopic gastrostomy (PEG) is the procedure of choice to achieve long-term enteral nutrition. The risks and benefits of PEG in elderly hospitalized patients have been poorly documented. The objective of this study was to describe the outcome of elderly patients one-year after insertion of a PEG tube.PATIENTS AND METHODS: Hospital records of 73 patients who underwent PEG for enteral nutrition were reviewed retrospectively. Data on patient age and sex, preexisting medical conditions such as dementia or pressure sores, indication for PEG, concomitant infection, complications of PEG and death were obtained from the hospital charts.RESULTS: The main indication for PEG was anorexia (49%). Before insertion of the gastrostomy tube, 44% of the patients had pressure scores, 30% had concomitant infection, 45% had dementia. PEG complications were observed in 51 patients. The survival rate at 1, 6 and 12 months was 0.68 [95% confidence interval - CI 95%: 0.56-0.78], 0.48 [CI 95%: 0.36-0.59] and 0.37 [CI 95%: 0.26-0.48] respectively. The presence of an infectious disease or of pressure sores at the time of PEG tube insertion were independently associated with mortality. Median survival of patients with these two factors was 32 days [CI 95%: 11-98].CONCLUSION: According to these results, the PEG tubes should be inserted with a delay from infectious diseases and before the occurrence of pressure sores.  相似文献   
78.
Blood fluidity is related to the ability to oxidize lipids at exercise   总被引:5,自引:0,他引:5  
We previously reported in rugbywomen correlations between RBC deformability and the ability to oxidize at exercise more lipids. This surprising finding might of course be spurious, or reflect the importance of the balance of substrates at exercise on baseline parameters that regulate blood rheology. Actually, the capacity of skeletal muscle to utilize either lipid or carbohydrate as fuels strongly influences whole body metabolism both at rest and during exercise. While the healthy skeletal muscle has substantial metabolic flexibility and is able to switch from predominantly lipid o oxidation during fasting or endurance exercise to increased glucose oxidation in conditions of insulin stimulation, obese individuals and those with type 2 diabetes manifest higher lipid oxidation during insulin-stimulated conditions despite lower rates of lipid oxidation during fasting or prolonged exercise. A low ability to oxidize and to periodically deplete triglyceride in muscle is associated with raised blood lipids. In addition, high carbohydrate oxidation rates in the mitochondrion are likely to promote more free radical generation. An increase in either blood lipids or free radicals is likely to induce profound hemorheological effects. We present here hemorheological studies in various populations with the use of exercise calorimetry in order to assess this switch of substrates. These studies further evidence negative correlations between the ability to oxidize lipids at exercise and parameters of blood viscosity. Correlations found between RBC deformability and the ability to oxidize at exercise more lipids may be due to effects of endurance training on lipid oxidation which may in turn modify both lipid metabolism and free radical generation, thus influencing RBC rheology.  相似文献   
79.
Adiponutrin is a newly identified nonsecreted adipocyte protein regulated by changes in energy balance in rodents. We documented the influence of energy balance modification on adiponutrin gene expression in humans. We investigated the mRNA expression in sc adipose tissue of nonobese women and in obese women during 2-d very low-calorie diet (VLCD) and subsequent refeeding as well as before and after a VLCD of 3 wk (21-d VLCD). The adiponutrin mRNA levels of the nonobese and obese women were not different (P > 0.05). Two-day VLCD reduced the average level of adiponutrin mRNA expression by 36% (P = 0.0016), whereas refeeding elevated the mRNA level by 31% (P = 0.004). The 3-wk VLCD caused a dramatic 58% fall of the adiponutrin mRNA expression level (P = 0.001). The mRNA level was negatively correlated with fasting glucose (Rho = -0.62; P < 0.0001), and subjects with high adiponutrin mRNA level had an increased insulin sensitivity. Compared with other adipocyte proteins such as leptin and adiponectin, adiponutrin mRNA did not show correlation with either adiposity indexes or with leptin or adiponectin mRNAs. These results indicate that adiponutrin gene expression in humans is highly regulated by changes in energy balance.  相似文献   
80.
OBJECTIVE: Because the absence of immune restoration in HIV-infected patients efficiently treated by highly active antiretroviral therapy (HAART) may be due to excessive immune activation, we prospectively studied the effect of hydrocortisone on T-cell apoptosis in a cohort of patients with satisfactory virologic response. METHODS: Apoptosis of T-cell subsets including na?ve CD45RA(+)CD4+ T-cells was determined at baseline and at months 1 and 3 after initiation of HAART. A satisfactory immune response was defined as an increase >100/microL CD4+ T-cells at month 3 compared to baseline. RESULTS: Twenty out of 63 patients showed undetectable viral load at month 3, among whom eight exhibited a satisfactory immune response. Down-regulation spontaneous CD4+T-cell apoptosis was significant in the group of patients with a satisfactory immune response compared to the other patients. However, hydrocortisone up-regulated apoptosis of na?ve CD4+ CD45RA+ T-cells, specifically in group of patients with poor immune response, whatever the time point considered: percentage of apoptotic CD4 T-cells was 16+/-16% without hydrocortisone and 22+/-22% with hydrocortisone at month 1, and respectively, 10+/-9 and 17+/-15% at month 3 (P < 0.05) Hydrocortisone had no impact on CD8+ T-cell apoptosis, whatever the considered group. CONCLUSION: Our results suggest to not use steroid therapy as adjuvant immunotherapy in patients with less than optimal immunologic response to HAART.  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