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   6130篇
  免费   340篇
  国内免费   69篇
耳鼻咽喉   101篇
儿科学   87篇
妇产科学   91篇
基础医学   703篇
口腔科学   142篇
临床医学   432篇
内科学   2044篇
皮肤病学   85篇
神经病学   741篇
特种医学   235篇
外科学   862篇
综合类   26篇
预防医学   204篇
眼科学   52篇
药学   329篇
中国医学   21篇
肿瘤学   384篇
  2023年   43篇
  2022年   52篇
  2021年   148篇
  2020年   100篇
  2019年   123篇
  2018年   181篇
  2017年   145篇
  2016年   154篇
  2015年   162篇
  2014年   224篇
  2013年   338篇
  2012年   477篇
  2011年   454篇
  2010年   283篇
  2009年   260篇
  2008年   391篇
  2007年   376篇
  2006年   356篇
  2005年   392篇
  2004年   341篇
  2003年   280篇
  2002年   236篇
  2001年   105篇
  2000年   98篇
  1999年   104篇
  1998年   37篇
  1997年   43篇
  1996年   41篇
  1995年   42篇
  1994年   25篇
  1993年   20篇
  1992年   46篇
  1991年   52篇
  1990年   39篇
  1989年   37篇
  1988年   47篇
  1987年   32篇
  1986年   28篇
  1985年   29篇
  1984年   26篇
  1983年   22篇
  1981年   11篇
  1980年   9篇
  1979年   16篇
  1978年   11篇
  1975年   9篇
  1974年   14篇
  1970年   12篇
  1969年   9篇
  1968年   9篇
排序方式: 共有6539条查询结果,搜索用时 31 毫秒
61.
BackgroundLymphatic disorders (LDs) are the most common minor complications after kidney transplantation (KT), with an incidence rate between 0.6% and 33.9%, which appears to be related to both surgical and medical factors. LDs mostly resolve spontaneously, but occasionally a surgical approach may be required.Materials and MethodsWe report our experience with 7 KT recipients who developed persistent lymphorrhea (>150 mL/24 h) between October 2017 and March 2019. All cases were treated as outpatients with parietal fistulectomy (PF). The fibrotic aponeurotic-cutaneous tract was thoroughly excised, and the residual aponeurotic defect was closed by watertight suturing. Serial abdominal ultrasounds (US) were carried out after the procedure.ResultsA small perirenal graft lymphocele of <2 cm was detected by US in all patients after 48 to 72 hours, without any evidence of either vascular or ureteral compression. During the subsequent scheduled US follow-up, lymphoceles did not increase in size, and additional interventions were not needed. Neither superficial nor deep surgical-site infections were recorded in such patients.ConclusionsPF was found to be a safe and effective minimally invasive approach for persistent lymphorrhea after KT. It could be easily performed with local anesthesia in a day surgery setting and did not require patient hospitalization.  相似文献   
62.
This study aimed to estimate the incidence of hospital‐acquired pressure injury (PI) and its risk factors in inpatient and intensive care units of five hospitals (two public and three private) in the city of Sao Paulo, Brazil. A 6‐month follow‐up prospective cohort study (n = 1937) was conducted from April to September 2013. Baseline and follow‐up measurements included demographic and care information, as well as risk assessments for both undernutrition (NRS‐2002) and PI (Braden scale). Poisson regression with robust variance was used for data analysis. A total of 633 patients (32.60%) showed risk for PI. The incidence rate of PI was of 5.9% (9.9% in public hospitals vs 4.1% in private hospitals) and was higher in intensive care units, compared to inpatient care units (10% vs 5.7%, respectively). Risk for PI increased with age (RR = 1.05; 95% CI 1.04‐1.07); was higher in in public hospitals, compared to private hospitals (RR = 4.39; 95% CI 2.92‐6.61); in patients admitted for non‐surgical reasons compared to those admitted for surgical reasons (RR = 1.91; 95% CI 1.12‐3.27); in patients with longer hospital stays (RR = 1.04; 95% CI 1.03‐1.06); high blood pressure (RR = 1.76; 95% CI 1.17‐2.64); or had a risk for undernutrition (RR = 3.51; 95% CI 1.71‐7.24). Higher scores in the Braden scale was associated with a decreased risk of PI (RR = 0.79; 95% CI 0.75‐0.83). The results of our study indicate that 5.9% of all patients developed PI and that the most important factors that nurses should consider are: patient age, care setting, length of hospitalization, comorbidities, reason for admission and nutrition when planning and implementing PI‐preventative actions.  相似文献   
63.
BackgroundSleeve gastrectomy (SG) has become the most prevalent bariatric-metabolic surgical approach in the United States. Its popularity among surgeons and patients is mainly due to a better safety profile and less overall morbidity, with broad benefits from a systemic and metabolic perspective.ObjectiveComprehensively describe the short-term multiorgan metabolic effects of rapid weight loss after SG.SettingAcademic hospital, United States.MethodsWe retrospectively reviewed the charts of patients that underwent SG at our institution between 2012 and 2016. We analyzed the required variables to calculate multiple risk scores, such as cardiovascular, hypertension, and diabetes risk scores. Furthermore, the renal and hepatic functions and the metabolic and hematologic profiles were assessed at 12 months of follow-up.ResultsA total of 1002 patients were included in the analysis. The percentage of excess body mass index loss was, on average, 65% at 12 months of follow-up. We observed a positive cardio-renal-hepatic improvement, demonstrated by a substantial reduction of the 10-year cardiovascular risk. We noticed an improvement of renal function, which was more significant in chronic kidney disease (stage ≥2), and a significant improvement on liver function tests (measured by decreased aspartate aminotransferase and alanine transaminase) at 12 months of follow-up. Our data also show a positive impact on decreasing the risk of developing hypertension and type 2 diabetes. There was a positive impact on the lipid profile, with the exception of low-density lipoprotein.ConclusionThere are significant short-term benefits on multiorgan metabolic parameters after rapid weight loss in severely obese patients undergoing sleeve gastrectomy.  相似文献   
64.
65.
HCV is ubiquitous. In 50% of all cases it causes chronic hepatitis that often evolves into liver cirrhosis and hepatocellular carcinoma. Recently HCV has been classified in 5 genotypes by Okamoto. The purpose of this study is to evaluate the prevalence of 5 genotypes in Campania, a region of Southern Italy, where the prevalence of anti-HCV antibodies ranges from 0.87 to 4%, and to evaluate the correlation between the HCV genotypes and the severity of histological damage. One hundred and thirty-five anti-HCV positive patients were enrolled and tested by PCR to identify HCV-RNA. One hundred and twenty-four patients resulted HCV-RNA positive. Genotyping was performed as described by Okamoto et al. with minor modifications of the specific primer to type III proposed by Silini et al. Eight patients were negative for all genotypes. Eight patients were positive for type I(1a), 61 for type II(1b), 39 for type III(2a), 11 for type IV(2b) and 1 for type V(3a). In 4 cases two different genotypes were present in the same sample [II(1b)-IV(2b), III(2a)-II(1b) twice, III(2a)-IV(2b)]. Histological evaluation of liver damage showed: CPH (22 cases), minimal CAH (56), severe CAH (31) and liver cirrhosis (15). There was no statistically significant correlation between the 5 genotypes and the severity of histological damage. Data on the prevalence of genotype II(1b) in Italy are similar to those reported for other European countries. The prevalence of genotypes in Southern Italy is similar to that reported in the population of Northern Italy.  相似文献   
66.
The qualitative results of FCM DNA analysis on fresh and fixed urine specimens (28 and 97, respectively) from 68 normal subjects and 10 patients with a past history of bladder cancer were compared. FCM DNA evaluability was not significantly different in fresh and fixed samples (63% vs 73%, respectively) whereas mean CV was significantly higher (7.3% vs 5.7%, respectively; p=0.04). A double FCM analysis on fresh and fixed urine was also performed in 16 cases. In this subgroup, the percentage of evaluable histograms from fixed urine specimens was slightly higher than that from fresh specimens. Aneuploid cases were found only in the fixed urine samples but the CVs from fresh and fixed cell suspensions did not differ. The absence of inflammatory cells with cytological analysis of the same samples was associated with low percentages of FCM evaluability and higher CVs. The use of fixed samples improves the quality of FCM DNA analysis permitting its use for screening programs.  相似文献   
67.
The aim of this study was to follow the fate of dietary nitrogen to assess the postprandial utilization of purified milk protein and to determine the acute influence of energy nutrients. For this purpose, a [15N]-labeling dietary protein approach was used. Twenty-five subjects swallowed an ileal tube and ingested [15 N]-milk protein alone or supplemented with either milk fat or sucrose. The absorption and postprandial deamination of dietary protein was monitored for 8 h. Sucrose delayed the absorption of protein longer than fat, but the ileal digestibility did not differ among groups (94.5-94.8%). Sucrose, but not fat, significantly reduced the postprandial transfer of [15N]-milk nitrogen to urea. Consequently, the net postprandial protein utilization (NPPU) of milk protein calculated 8 h after meal ingestion was 80% when ingested either alone or supplemented with fat and was significantly greater with sucrose (NPPU = 85%). This study shows that energy nutrients do not affect the nitrogen absorption but modify the metabolic utilization of dietary protein in the phase of nitrogen gain. Our method provides information concerning the deamination kinetics of dietary amino acids and further allows the detection of differences of dietary protein utilization in acute conditions. The diet composition should be carefully considered, and protein quality must be determined under optimal conditions of utilization.  相似文献   
68.
69.
OBJECTIVES: To assess whether different definitions of acute coronary events yielded concordant results concerning trends and geographical disparities in coronary heart disease (CHD) mortality and morbidity in France. STUDY DESIGN: Data from three French CHD registries participating in the WHO MONICA Project during the period 1985-1992. SETTING: Three areas of about one million inhabitants each in the North, South and East of France. SUBJECTS: About 2,000 acute coronary events each year. MAIN OUTCOME MEASURES: Mortality, annual rate of fatal and non-fatal events, incidence of first and recurrent events, case-fatality rates. RESULTS: For incidence and mortality, the broader the broader the definition of the acute event, the higher the reported rates. The same tendency was not observed for case-fatality rates. Comparing between-registry rates for mortality, 28-day case-fatality and hospital case fatality yielded relatively concordant results whatever the definition of event. As a whole, the higher mortality rate in Lille and its intermediate rank in Strasbourg were related more to disparities in case-fatality rates, with only small variations in incidence rates, independently of the definition used. Comparing temporal trends in rates within and between regions, a consistent decrease in annual mortality rates and case-fatality rates was observed, whatever the definition. In contrast, the incidence of non-fatal probable myocardial infarction did not change during the period in any register. CONCLUSIONS: Although the absolute estimates of rates were variable with the definition of the event, major findings in relation to trends and geographical disparities were fairly consistent across the definitions: the North-South gradient in mortality observed in France was found to be much more pronounced for case fatality than for incidence. The proportion of milder acute myocardial infarction is currently increasing and this element should be taken into account when analysing CHD rates.  相似文献   
70.
vgf is an inducible gene, highly sensitive to nerve growth factor (NGF) and remarkably upregulated in the "early-delayed" phase of response (within a few hours). It encodes a 617-amino acid polypeptide (VGF protein) bearing no significant homology with known sequences and restricted to certain peptide/amine-producing endocrine cells, and neurons (for example, adenohypophysial and adrenal medullary cells, or hypothalamic neuroendocrine neurons). VGF is stored and transported in secretory granules and processed to intermediate-small molecular weight products, which are preferentially released. Striking changes in both VGF mRNA and immunolocalization are found in physiological conditions (for example, estrous cycle) and in experimental models of stimulation affecting hypothalamic and other neurons. Functional roles of VGF are to be sought in secretory granule formation and regulation, and/or in the production of potentially bioactive peptides.  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