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   2177篇
  免费   82篇
  国内免费   26篇
耳鼻咽喉   4篇
儿科学   24篇
妇产科学   9篇
基础医学   248篇
口腔科学   21篇
临床医学   160篇
内科学   708篇
皮肤病学   20篇
神经病学   88篇
特种医学   70篇
外科学   394篇
综合类   6篇
预防医学   60篇
眼科学   11篇
药学   102篇
中国医学   4篇
肿瘤学   356篇
  2023年   8篇
  2022年   32篇
  2021年   36篇
  2020年   25篇
  2019年   36篇
  2018年   52篇
  2017年   37篇
  2016年   38篇
  2015年   41篇
  2014年   66篇
  2013年   64篇
  2012年   132篇
  2011年   134篇
  2010年   88篇
  2009年   72篇
  2008年   114篇
  2007年   127篇
  2006年   102篇
  2005年   113篇
  2004年   127篇
  2003年   121篇
  2002年   128篇
  2001年   38篇
  2000年   49篇
  1999年   56篇
  1998年   38篇
  1997年   36篇
  1996年   25篇
  1995年   19篇
  1994年   17篇
  1993年   24篇
  1992年   39篇
  1991年   25篇
  1990年   32篇
  1989年   27篇
  1988年   16篇
  1987年   20篇
  1986年   22篇
  1985年   16篇
  1984年   6篇
  1983年   7篇
  1981年   5篇
  1979年   5篇
  1974年   5篇
  1973年   5篇
  1972年   4篇
  1971年   5篇
  1970年   10篇
  1968年   5篇
  1967年   6篇
排序方式: 共有2285条查询结果,搜索用时 15 毫秒
71.

Background

The impact of paraoxonase-1 (PON1) activity on the response to clopidogrel may differ in patients treated with drug-eluting stents (DES) in association with CYP2C19 loss-of-function (LOF) polymorphisms.

Methods

This study included 112 Japanese patients receiving clopidogrel (75 mg/day) and aspirin (100 mg/day) who underwent optical coherence tomography (OCT) examination 9 months after DES implantation. The CYP2C19 genotype was analyzed and LOF carriers (*1/*2, *1/*3, *2/*2, *3/*3, *2/*3) were identified. At the 9-month follow-up, platelet reactivity was determined by measuring the P2Y12 reactivity unit (PRU) using a VerifyNow P2Y12 assay, PON1 activity was evaluated and intra-stent thrombus was evaluated by OCT.

Results

Of the 112 Japanese patients, 75 were LOF carriers (67.0%). The patients were divided into tertiles according to the PON1 activity (tertile 1; < 230 U/L, tertile 2; 230–283 U/L, tertile 3; > 283 U/L). In the VerifyNowP2Y12 analysis, tertile 1 had a higher PRU than tertiles 2 and 3 in LOF carriers, and there was no difference among tertiles in non-carriers. The highest incidence of intra-stent thrombus was observed in tertile 1 followed by tertiles 2 and 3 in LOF carriers, whereas there was no such difference in non-carriers. Multivariate analysis revealed that LOF carriers and PON1 activity tertile 1 were independent predictors of intra-stent thrombus in all patients. In LOF carriers, tertile 1 was the only independent predictor for intra-stent thrombus.

Conclusion

Low PON1 activity is associated with a low response to clopidogrel and a high frequency of intra-stent thrombus only in LOF carriers.  相似文献   
72.
73.

Purpose

Anastomotic leakage (AL) is a critical complication of colorectal cancer surgery. The transanal drainage tube (TDT) is designed to prevent AL caused by decompression and stasis at the anastomosis. We conducted this study to investigate the feasibility of using the TDT to prevent AL following double-stapling technique reconstruction (DST).

Methods

The subjects of this study were 179 patients who underwent curative resection and DST reconstruction for sigmoid colon and rectal cancer in our institution between 2008 and 2013. We analyzed the effectiveness of the TDT for preventing AL.

Results

A TDT was placed in 78 patients (43.6 %, TDT group) and not placed in the remaining 101 patients (56.4 %, NTDT group). AL developed in 2 (2.6 %) patients from the TDT group and in 14 (13.9 %) patients from the NTDT group (p = 0.009). Univariate analysis revealed that AL was significantly correlated with tumor distance from the anal verge (AV), the number of staples, and TDT placement. Multivariate analysis revealed a significantly positive correlation between AL and AV [OR 0.877 (0.783–0.982) p = 0.023] and a significantly negative correlation between AL and TDT placement [OR 0.07 (0.013–0.374) p = 0.002].

Conclusions

Anastomotic decompression with TDT placement may prevent AL after colorectal cancer surgery with DST reconstruction.
  相似文献   
74.
Ayu TNF cDNA contains an open reading frame of 708bp encoding 235 amino acids. Poly adeniration (A) signal and eight AU-rich sequences were present in 858bp 3' UTR. Southern blot analysis indicated that ayu TNF is single-copy gene. The genomic DNA sequence of ayu TNF, consisting of four exons and three introns, was shown to be conserved well throughout evolution from fish to mammals. The amino acid sequence of ayu TNF was shown to have 32-41% of amino acid identity to other known fish TNF, and about 30% of amino acid identity to mammalian TNFs. A phylogenetic analysis based on the amino acid sequence of TNF indicated that ayu has a distinctive evolutionary path. Also, two residues of cysteine important for the formation of the three-dimensional structure were conserved in ayu TNF. For the functional analysis, ayu TNF was inserted into expression vector pCold/TF, transferred into Chaperone Competent Cells BL21 (pKJE7); this produced soluble mature ayu recombinant TNF. Ayu recombinant TNF was shown to induce respiratory burst activity from ayu kidney. The above results indicate that ayu TNF plays an important role in phylaxis, as it does in mammals.  相似文献   
75.
PURPOSE: The purpose of this study was to investigate the relationship between self-assessed satisfaction with mastication and food acceptability and masticatory performance in a large sample of older adults with various occlusal statuses. MATERIALS AND METHODS: The subjects were 708 community-dwelling, independently living elderly persons (351 men and 357 women) with a mean age of 66.0 (SD: 4.2) years. Satisfaction with masticatory function and food acceptability (apples, grilled beef, and hard rice crackers) were evaluated using questionnaires. Masticatory performance was determined using test gummy jellies developed for measuring masticatory performance. Subjects were grouped into 3 categories by posterior occlusal contacts according to the Eichner Index. The Kruskal-Wallis test and a multiple logistic regression analysis for dissatisfaction with masticatory function were conducted. RESULTS: Overall, posterior occlusal contacts, food acceptability, and masticatory performance were associated with satisfaction with masticatory function when evaluated with bivariate analysis. Multiple logistic regression analysis showed that the number of foods that could be eaten without difficulty was the most important explanatory variable for dissatisfaction with masticatory function (P < .01). In contrast, objective masticatory performance was not significantly associated with dissatisfaction with masticatory function (P = .057) after controlling for posterior occlusal contacts and food acceptance. CONCLUSIONS: The subjective masticatory function was associated not only with objective masticatory performance, but also with an individual's posterior occlusal contacts.  相似文献   
76.
77.
78.

In the treatment of an intracranial aneurysm with the flow diverter, the combined use of coil embolization can help promote subsequent progressive thrombosis within the aneurysm sac and reduce the risk of delayed aneurysm rupture. This study retrospectively reviewed outcomes of patients who had undergone the Pipeline Embolization Device (PED) with adjunctive coil embolization (PED/coil) at a single center to determine its safety and efficiency. Patients with internal carotid artery aneurysms following an intradural component were selected for PED/coil between 2015 and 2020. All patients were premedicated with dual antiplatelet therapy of aspirin plus clopidogrel or prasugrel. A minimal number of PEDs were deployed, with coils inserted using a stent-jail technique, avoiding dense packing. A total of 46 aneurysms (43 patients; median dome size, 11.6 mm; median neck width, 6.3 mm) were treated with PED/coil. The median volume embolization ratio was 14.8%. The degree of angiographic filling at the 6-month and latest angiography showed complete occlusion in 60.5% (26/43) and 70.5% (31/44), respectively. Small (<?10 mm) aneurysms achieved a higher complete occlusion rate in the early period; a lower cumulative incidence of aneurysm occlusion was observed in large and giant (≥?10 mm) aneurysms (P?=?.024). The median clinical follow-up was 22 months, and no aneurysm ruptures occurred. Favorable clinical outcomes were achieved, with permanent neurological morbidity of 4.7% and no mortality. PED/coil demonstrated a high angiographic occlusion rate at an early stage. Loosely packed coils are sufficient to obliterate aneurysms effectively.

  相似文献   
79.

Background

The effectiveness of 5-fluorouracil (5-FU)-based adjuvant chemotherapy is reported in patients with colorectal cancer (CRC), but the usefulness of 5-FU metabolic enzymes as predictive biomarkers of the efficacy of this chemotherapy remains unclear.

Objective

This study aims to verify whether 5-FU metabolic enzymes are predictive biomarkers in the clinical setting of adjuvant chemotherapy for stage II/III CRC.

Methods

In total, 179 patients with stage II/III CRC who were treated at our institute between 2000 and 2010 were enrolled. Messenger RNA (mRNA) expression of major 5-FU metabolic enzymes, namely thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase (TP), orotate phosphoribosyl transferase, and β-actin (control) was evaluated using the Danenberg Tumor Profile method. mRNA expression and other clinicopathological data were investigated with regard to CRC relapse.

Results

A total of 78 patients underwent surgery alone, while 101 underwent adjuvant chemotherapy (5-FU plus leucovorin [LV] or tegafur plus uracil /LV) following surgery. Relapse-free survival was longer and risk of recurrence was lower in association with high TP mRNA expression than in association with low TP mRNA expression in the adjuvant chemotherapy group (hazard ratio 0.66; 95 % confidence interval 0.47–0.92; p = 0.016), but not in the surgery alone group. mRNA expression of no other enzymes was associated with relapse in both groups. In decision-curve analyses, the predictive efficiency of TP mRNA expression plus clinicopathological factors was slightly better than that of clinicopathological factors only.

Conclusions

TP mRNA expression in tumors predicted the effects of adjuvant chemotherapy for stage II/III CRC, although the beneficial effects were marginal.  相似文献   
80.
To distinguish the characteristics of ruptured cerebral aneurysm that are suitable for endovascular treatment from those that are not, we evaluated factors that influenced the results of aneurysm embolization in patients with ruptured cerebral aneurysm, based on data from the Japanese Registry of Neuroendovascular Therapy (JR-NET) 1 and 2. The multivariate analysis revealed that young patients, patients with low modified Rankin Scale (mRS) scores before onset, and patients with low World Federation of Neurosurgical Societies (WFNS) grades had good outcome. Compared to proximal internal carotid artery (ICA) aneurysms, the odds ratio of middle cerebral artery (MCA) aneurysms was 1.67, indicating poorer outcome for MCA aneurysms, and patients with small, wide-neck cerebral aneurysms had poor outcome. Patients treated after 15 days had better outcome than during other periods. The timing of treatment, however, did not influence the outcome in patients treated within 14 days. The outcome was poorer when the responsible doctor for the treatment was a specialist or a non-specialist than a supervisory doctor. The outcome of patients treated with bare platinum coils, and three dimensional (3D) rotational angiography was better, and the outcome of patients who completed treatment with body filling was poorer than in patients with complete occlusion. Perioperative hemorrhagic complications, all ischemic complications, and rebleeding occurred in 4.5%, 6.4%, and 1.4% of patients, respectively. All these complications had poor outcome factors on day 30, with odds ratios of 2.72, 2.96, and 25.49, respectively. We must be fully aware of these risk factors and determine indications for the treatment when endovascular treatment is performed as the treatment of choice for ruptured cerebral aneurysm.  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