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   4782篇
  免费   301篇
  国内免费   140篇
耳鼻咽喉   99篇
儿科学   90篇
妇产科学   47篇
基础医学   709篇
口腔科学   98篇
临床医学   406篇
内科学   987篇
皮肤病学   182篇
神经病学   336篇
特种医学   414篇
外科学   717篇
综合类   42篇
预防医学   205篇
眼科学   54篇
药学   460篇
中国医学   50篇
肿瘤学   327篇
  2023年   32篇
  2022年   86篇
  2021年   135篇
  2020年   75篇
  2019年   92篇
  2018年   148篇
  2017年   91篇
  2016年   163篇
  2015年   186篇
  2014年   293篇
  2013年   289篇
  2012年   376篇
  2011年   369篇
  2010年   212篇
  2009年   214篇
  2008年   246篇
  2007年   292篇
  2006年   257篇
  2005年   262篇
  2004年   201篇
  2003年   170篇
  2002年   170篇
  2001年   91篇
  2000年   84篇
  1999年   85篇
  1998年   43篇
  1997年   31篇
  1996年   49篇
  1995年   40篇
  1994年   36篇
  1993年   29篇
  1992年   43篇
  1991年   45篇
  1990年   36篇
  1989年   30篇
  1988年   37篇
  1987年   22篇
  1986年   29篇
  1985年   16篇
  1984年   13篇
  1983年   15篇
  1982年   11篇
  1980年   4篇
  1979年   14篇
  1978年   7篇
  1977年   10篇
  1976年   8篇
  1975年   7篇
  1974年   8篇
  1972年   4篇
排序方式: 共有5223条查询结果,搜索用时 15 毫秒
61.
Introduction of HIV type 1 subtype E virus into South Korea   总被引:1,自引:0,他引:1  
Subtype E HIV-1 is the most prevalent strain in Southeast Asia. Although subtype B is prevalent in Korea, geographical distance and increases in travel may lead to the spread of subtype E in Korea. Therefore, we tried to identify and monitor the patterns of HIV subtype E virus introduction into Korea. The divergence of nucleotide sequences within the envelope region (V3 to V5) of Korean subtype E isolates ranged from 4.3 to 14.6% (n = 8; mean, 9.5 +/- 2.8%). In pairwise comparisons of subtype E isolates between Korea and other regions, the divergence of nucleotide sequences between 8 Korean and 16 Asian subtype E variants ranged from 1.3 to 15.2% (mean, 7.8 +/- 2.6%), whereas the divergence of nucleotide sequences between 8 Korean and 2 African variants ranged from 11.7 to 20.7% (mean, 15.4 +/- 2.2%). A phylogenetic tree showed that Korean subtype E isolates cluster with the Asian isolates but far from the African isolates. These epidemiological and molecular epidemiological data suggest that HIV-1 subtype E strains have been transmitted into Korea from endemic areas of Southeast Asia rather from Africa.  相似文献   
62.
This study evaluated the 5-year clinical outcomes of the Genoss DES, the first Korean-made sirolimus-eluting coronary stent with abluminal biodegradable polymer.We previously conducted the first-in-patient prospective, multicenter, randomized trial with a 1:1 ratio of patients using the Genoss DES and Promus Element stents; the angiographic and clinical outcomes of the Genoss DES stent were comparable to those of the Promus Element stent. The primary endpoint was major adverse cardiac events (MACE), which was a composite of death, myocardial infarction (MI), and target lesion revascularization (TLR) at 5 years.We enrolled 38 patients in the Genoss DES group and 39 in the Promus Element group. Thirty-eight patients (100%) from the Genoss DES group and 38 (97.4%) from the Promus Element group were followed up at 5 years. The rates of MACE (5.3% vs 12.8%, P = .431), death (5.3% vs 10.3%, P = .675), TLR (2.6% vs 2.6%, P = 1.000), and target vessel revascularization (TVR) (7.9% vs 2.6%, P = .358) at 5 years did not differ significantly between the groups. No TLR or target vessel revascularization was reported from years 1 to 5 after the index procedure, and no MI or stent thrombosis occurred in either group during 5 years.The biodegradable polymer Genoss DES and durable polymer Promus Element stents showed comparable low rates of MACE at the 5-year clinical follow-up.  相似文献   
63.
This research aimed to investigate the changes in ethical issues in everyday clinical practice recognized by critical care nurses during two observation periods. We conducted a retrospective analysis of data obtained by prospective questionnaire surveys of nurses in the intensive care units (ICU) of a tertiary university-affiliated hospital in Seoul, Korea. Data were collected prospectively during two different periods, February 2002-January 2003 (Period 1) and August 2011-July 2012 (Period 2). Significantly fewer cases with ethical issues were reported in Period 2 than in Period 1 (89 cases [2.1%] of 4,291 ICU admissions vs. 51 [0.5%] of 9,302 ICU admissions, respectively; P < 0.001). The highest incidence of cases with identified ethical issues in both Periods occurred in MICU. The major source of ethical issues in Periods 1 and 2 was behavior-related. Among behaviorrelated issues, inappropriate healthcare professional behavior was predominant in both periods and mainly involved resident physicians. Ethical issue numbers regarding end-oflife (EOL) care significantly decreased in the proportion with respect to ethical issues during Period 2 (P = 0.044). In conclusion, the decreased incidence of cases with identified ethical issues in Period 2 might be associated with ethical enhancement related with EOL and improvements in the ICU care environment of the studied hospital. However, behaviorrelated issues involving resident physicians represent a considerable proportion of ethical issues encountered by critical care nurses. A systemic approach to solve behavior-related issues of resident physicians seems to be required to enhance an ethical environment in the studied ICU.

Graphical Abstract

相似文献   
64.

Objectives

To evaluate the effect of obstructive sleep apnea (OSA) surgery on long-term (5-year) subjective outcomes, including sleep disordered breathing (SDB) symptoms and other complications, in patients with OSA.

Methods

We enrolled patients who underwent diagnostic polysomnography for OSA between January 2006 and December 2006 in ten hospitals. Patients either were treated for OSA or were not treated for OSA. All patients completed a brief telephone survey regarding their SDB signs and symptoms (e.g., snoring, apnea, nocturnal arousals, and daytime sleepiness), positive airway pressure (PAP) compliance, and any adverse effects of either the surgery or PAP. A positive subjective outcome for either surgery or no treatment was taken to be the alleviation of apnea, defined as a ≥50% increase in score. A positive subjective outcome (compliance) for PAP was defined as a PAP usage of ≥4 hours per night and ≥5 days per week.

Results

A total of 229 patients were included in this study. Patients were divided into three groups: a surgery group (n=87), a PAP group (n=68), and a control (untreated) group (n=74). The surgery group exhibited significant improvement in all SDB symptoms compared with the control group. The long-term subjective outcomes of the surgery (52.9%) and PAP (54.4%) groups were significantly better than those of the control group (25.0%). The subjective outcome of the surgery group was not significantly different from that of the PAP group. The overall surgical complication rate was 23.0% (20 of 87) in the surgery group, and 55.0% (22 of 40) of all patients with PAP experienced adverse effects.

Conclusion

The extent of SDB symptoms was consistently improved in patients with OSA at 5 years postsurgery. Information about the potential long-term subjective outcomes should be provided to patients when considering surgery.  相似文献   
65.
Although the APC protein is known to participate in cellular proliferation and apoptosis, APC mutations have been thought to play a major role in the early stage of colorectal tumorigenesis. The somatic APC mutation of exon 15 was assessed to determine its impact on various stages of colorectal tumorigenesis. The colorectal neoplastic tissues of serial array studied included sporadic adenomas (group 1, n = 36), adenomas (group 2, n = 33), and carcinomas (group 3, n = 32) in the synchronous adenoma and carcinoma as well as sporadic carcinomas (group 4, n = 36). Aberrant DNA was detected by protein truncation test and confirmed by direct sequencing. The mutation prevalence was 36.1% in group 1, 45.5% in group 2, 59.4% in group 3, and 41.7% in group 4 with no differences among the groups. Among the 18 patients with synchronous adenoma and carcinoma, 9 had mutation in their adenomas and 12 in their carcinomas. The mutation loci and patterns did not differ in adenomas and carcinomas. Mutations in the mutation cluster region (MCR) were much more frequent than in the preceding region of MCR, i.e., 85.7% vs. 14.3%. The mutation prevalence of villous adenomas appeared greater than that of tubular adenoma (3/21 vs. 3/4). Predominant pathogenic mutations at MCR suggest that the APC mutation is implicated in all stages of colorectal tumorigenesis.  相似文献   
66.

Objectives

The aim of this study was to investigate clinical outcomes after left main coronary artery (LM) bifurcation percutaneous coronary intervention (PCI) and the impact of the duration of dual antiplatelet therapy (DAPT) according to treatment strategy.

Background

There are limited data regarding the optimal PCI strategy for LM bifurcation lesions with new-generation drug-eluting stents.

Methods

A patient-level pooled analysis of 5 nationwide multicenter registries was performed. Rates of target lesion failure, thrombotic adverse cardiovascular events, and their individual components at 3-year were analyzed. Subgroup analysis according to DAPT duration was performed.

Results

From 13,172 patients undergoing PCI with new-generation drug-eluting stents, a total of 700 patients were treated for LM bifurcation lesions, 567 with a 1-stent strategy and 133 with a 2-stent strategy. Rates of target lesion failure and target lesion revascularization were higher in the 2-stent group, driven mainly by complex lesion profiles. Risks for thrombotic adverse cardiovascular events and its components were comparable between the 2 strategies. Subgroup analysis showed that risks for target lesion failure and thrombotic adverse cardiovascular events in the 2-stent group were significantly higher than in the 1-stent group in those with DAPT interruption <1 year, while they were similar in those receiving DAPT maintenance ≥1 year.

Conclusions

Up to 20% of patients who underwent LM bifurcation PCI eventually required a 2-stent strategy, which was as safe as a 1-stent strategy with the use of new-generation drug-eluting stents. Careful pre-emptive case selection as well as prolonged DAPT may be necessary when considering a 2-stent strategy in LM PCI given its higher rate of repeat revascularization and lesion failure than the 1-stent approach.  相似文献   
67.
In patients with aortic regurgitation (AR), a precise preoperative assessment of aortic valve (AV) pathology is important if AV repair or sparing operation is an alternative option. The aim of this study was to assess the diagnostic accuracy of computed tomography (CT) for evaluating the AR mechanism compared with surgical inspection. 59 patients with AR who underwent AV surgery and preoperative cardiac CT were evaluated. AR mechanism was classified into type 1 (aortic dilatation or cusp perforation), type 2 (prolapsed cusp) and type 3 (cusp retraction). Agreement between CT and surgical inspection was obtained. Correlation between aortic regurgitant orifice (ARO) and imaging parameters were evaluated. On surgical inspection, type 1 AR was noted in 22 patients, type 2 in 16 and type 3 in 21. Agreement regarding the AR mechanism on CT was excellent (intra-class correlation coefficient, 0.81). At the patient level, the Cohen’s κ value for CT findings with surgical inspection was of 0.89. At the cusp level, moderate agreement was noted between CT and surgical inspection. In the per-cusp analysis, CT had a sensitivity of 72.6%, specificity of 85.1%, positive predictive value of 73.8% and negative predictive value of 84.3% for the detection of aortic cusp abnormality. The diameter, perimeter and area of aortic annulus had moderate correlation with ARO (r?=?0.54–0.66, P?<?0.001). CT-derived classification of AR mechanism showed excellent agreement with surgical inspection.  相似文献   
68.
There is limited data on the efficacy of paclitaxel-coated balloon (PCB) compared to stents for de novo coronary lesions. The purpose of this study was to compare the efficacy of PCB treatment with stent implantation for de novo coronary lesions after successful plain old balloon angioplasty (POBA) guided by fractional flow reserve (FFR). In 200 patients scheduled for elective percutaneous coronary intervention (PCI) for de novo lesions, FFR was measured after POBA (POBA–FFR). If POBA–FFR was ≥?0.75, patients were treated with PCB (PCB group, n?=?78) or stent (Stent group, n?=?73). If POBA–FFR was <?0.75, stent was implanted as planned (Reference group, n?=?42). The primary endpoint was late lumen loss at 9 months and the secondary endpoint was adverse cardiac events (cardiac death, myocardial infarction, target lesion thrombosis, or repeat revascularization) at 12 months follow-up. There was no between-group differences in the POBA–FFR (0.87?±?0.05 in PCB, 0.89?±?0.06 in stent, p?=?0.101). At 9 months, late lumen loss was significantly lower in the PCB group compared to the Stent group (0.05?±?0.33 vs. 0.59?±?0.76 mm, p?<?0.001). Adverse cardiac events were not different between the PCB, Stent and Reference groups (2.6, 5.5, and 9.5% respectively; p?=?0.430 for PCB vs. Stent group; p?=?0.229 for the reference vs. both other groups). PCB treatment guided by POBA–FFR showed excellent 9 months angiographic and functional results, as well as comparable 12 months clinical outcomes, compared with stent implantation for de novo coronary lesions.  相似文献   
69.
70.
AIM: To study the clinical significance of minimal ascites, which was only defined by the CT and whose nature was not determined preoperatively, in the relationship with the peritoneal carcinomatosis. METHODS: The medical records and the dynamic CT films of 118 patients with gastric cancer were reviewed. Factors associated with peritoneal carcinomatosis were analyzed in 40 patients who had CT-defined ascites of which the nature was surgically confirmed. RESULTS: Only 12.5-25% of the CT-defined minimal ascites, whose volume was estimated to be less than 50 mL, were associated with peritoneal carcinomatosis. When the estimated CT-defined ascitic volume was 50 mL or more, peritoneal carcinomatosis was identified in 75-100%. When CT-defined lymph node enlargements were not found beyond the regional gastric area, perigastric invasions were not suspected, and the size of tumor was less than 3 cm, peritoneal carcinomatosis seemed significantly less accompanied at the univariate analysis. However, except for the minimal volume of CT-defined ascites in comparison with the mild or more, other factors were not confirmed multivariately. CONCLUSION: In the patients with gastric cancer, CT-defined minimal ascites alone is rarely associated with peritoneal carcinomatosis, if it does not accompany other signs suggestive of malignant seeding. Therefore, consideration of active curative resection should not be hesitated, if CT-defined minimal ascites is the only delusive sign.  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