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   3577篇
  免费   154篇
  国内免费   19篇
耳鼻咽喉   49篇
儿科学   70篇
妇产科学   39篇
基础医学   422篇
口腔科学   73篇
临床医学   218篇
内科学   1094篇
皮肤病学   32篇
神经病学   341篇
特种医学   131篇
外科学   607篇
综合类   10篇
预防医学   106篇
眼科学   26篇
药学   215篇
中国医学   4篇
肿瘤学   313篇
  2023年   22篇
  2022年   38篇
  2021年   85篇
  2020年   40篇
  2019年   59篇
  2018年   66篇
  2017年   59篇
  2016年   61篇
  2015年   67篇
  2014年   88篇
  2013年   108篇
  2012年   171篇
  2011年   224篇
  2010年   127篇
  2009年   86篇
  2008年   151篇
  2007年   185篇
  2006年   203篇
  2005年   169篇
  2004年   205篇
  2003年   166篇
  2002年   188篇
  2001年   84篇
  2000年   99篇
  1999年   99篇
  1998年   57篇
  1997年   35篇
  1996年   38篇
  1995年   25篇
  1994年   37篇
  1993年   40篇
  1992年   63篇
  1991年   69篇
  1990年   67篇
  1989年   52篇
  1988年   40篇
  1987年   51篇
  1986年   31篇
  1985年   35篇
  1984年   33篇
  1983年   24篇
  1982年   17篇
  1981年   15篇
  1980年   16篇
  1979年   24篇
  1978年   12篇
  1977年   12篇
  1975年   12篇
  1974年   11篇
  1973年   13篇
排序方式: 共有3750条查询结果,搜索用时 15 毫秒
91.
The large Japanese wood mouse (Apodemus speciosus) is common, but endemic to Japan, and its population structure was affected by habitat fragmentation because of urbanization. It suggested that the species might be one of the important models for the conservation of ecosystems and biodiversity affected by humans, including the effect of radioactive discharge caused by nuclear power plant accidents at Fukushima. We developed and characterized 25 novel polymorphic microsatellite markers from the next-generation sequencing data in an effort to provide an effective tool for genetic studies on this species. In 8 individuals from Aomori, Japan, the number of alleles and expected heterozygosities ranged from 5 to 13 and from 0.795 to 0.991, respectively, suggesting the availability of these markers for genetic studies in this species.  相似文献   
92.
The perceived intensity of the taste of a food is enhanced only if the odor of the food is perceptually similar to the taste. For example, a caramel-like odor enhances the perceived intensity of sweetness. The way gustatory and olfactory signals are integrated in the brain depends largely on one’s previous experiences with taste and odor pairings. To elucidate the effects of a sweet, sugary odor, ethylmaltol, on sucrose taste, as perceived by the central integration of flavor, we recorded salivary hemodynamic responses to the odor and taste pairings using near-infrared spectroscopy (NIRS) of seven panelists. First, we observed concentration-dependent increases in the amplitude of the responses to 0 to 6 % sucrose solutions. Second, when ethylmaltol odor was added to a 4 % sucrose solution, we observed a significant increase in the amplitude of the responses from all panelists. The addition of ethylmaltol to a tasteless solution caused no significant change in the amplitude of the salivary hemodynamic response. These results indicate that the sweet odor of ethylmaltol enhances the salivary hemodynamic response when combined with a sweet taste. Therefore, a congruent combination of sweet odor and taste greatly enhances salivary responses, which are dependent on the central integration of odor and taste.  相似文献   
93.
94.
95.
In order to test for improved survival following autologous transplantation (ASCT), we conducted a prospective clinical trial of post-ASCT thalidomide therapy in Japanese patients with multiple myeloma (MM). Twenty-five newly diagnosed patients received double or single ASCT with high-dose melphalan (200?mg/m2). Two months after stem cell infusion, if the patients failed to achieve a near-complete response, thalidomide was administered at 200?mg/day until disease progression or occurrence of intolerable adverse events. Seventeen patients were in partial response or minimal response after ASCT and received thalidomide alone. Their median progression-free survival (PFS) from ASCT was 17.4?months, and the median overall survival (OS) was 42.9?months. Some patients with normal karyotype experienced durable disease stabilization for over 5?years. Five patients who exhibited high-risk chromosomal changes such as t(4;14) or deletion of chromosome 13 or 17 showed very short PFS and OS compared with those who did not. Observed grade 3 or 4 toxicities included infection in three patients, hematological toxicities in three, and gastrointestinal toxicities in two, but there was no grade 3 or higher peripheral neuropathy, probably due to appropriate dose modifications. This long-term prospective study is the first to demonstrate the feasibility of post-ASCT thalidomide therapy in Japanese patients with MM.  相似文献   
96.
BackgroundHypersensitivity pneumonitis (HP) is an immune-mediated lung disease induced by inhalation of numerous antigens. Pathologically, chronic HP tends to show usual interstitial pneumonia (UIP) and fibrotic nonspecific interstitial pneumonia (fNSIP) patterns. Patients with UIP pattern present insidious onset and a risk for acute exacerbations.MethodsTo evaluate the proteomic differences of bronchoalveolar lavage fluid (BALF) between UIP and fNSIP patterns, BALF from seven patients with UIP pattern and four patients with fNSIP pattern was examined using two-dimensional gel electrophoresis and mass spectrometry.ResultsBy individually comparing each BALF sample, we found that the protein levels of surfactant protein A (SP-A), immunoglobulin heavy chain α, α-2 heat shock glycoprotein, haptoglobin β, and immunoglobulin J chain were significantly higher in the patients with UIP pattern than those in the patients with fNSIP pattern. In contrast, the protein levels of glutathione s-transferase, vitamin D-binding protein, and β-actin were significantly higher in the patients with fNSIP pattern than those in the patients with UIP pattern. To confirm the results of SP-A in the BALF proteome, we performed enzyme-linked immunosorbent assay in a larger group. The concentrations of SP-A in BALF from the patients with UIP pattern were significantly higher than those from the patients with fNSIP pattern (2.331 ± 1.656 μg/ml vs. 1.319 ± 1.916 μg/ml, p = 0.034).ConclusionsWe identified several proteins that may play roles in the development of pathological differences between UIP and fNSIP patterns of chronic HP.  相似文献   
97.

Objective

We implemented a retrospective study to explore discontinuation of therapy with adalimumab (ADA) without exacerbation in rheumatoid arthritis (RA) patients who had achieved low disease activity (LDA) with the biological agent.

Methods

We enrolled 46 RA patients who had completed open extension of a double-blind, placebo-controlled trial of ADA monotherapy in Japan and who had LDA (DAS28-CRP <2.7) at the last administration of ADA in the extension trials; this date was defined as week 0 in the present study. Treatment of RA was at the discretion of the attending physician after week 0. The primary endpoint of this study was the percentage of patients who maintained discontinuation of biological agents and LDA for 52?weeks.

Results

Twenty-four of the enrolled patients continued ADA while the rest discontinued ADA after the administration of the drug at week 0. Fourteen of the 22 patients did not restart biological agents, and 4 (18.2%) of these maintained LDA through week 52. All 4 of these patients had received ADA monotherapy before week 0.

Conclusion

Some RA patients who have achieved LDA with ADA monotherapy can discontinue the biologic without incurring increased disease activity. A prospective randomized study is required to confirm the results of our study.  相似文献   
98.
The effect of the addition of alcohol to a Na3PO4-based electrolyte on plasma electrolytic oxidation (PEO) of AZ31B magnesium alloy was investigated. Anodization with spark discharge was conducted in Na3PO4-based electrolyte containing various alcohols (e.g., ethanol, ethylene glycol, and glycerol) at a constant current density of 200 A m−2 and a constant temperature of 25 °C. Voltage–time curves during the PEO process, the film structure, surface roughness, crystallographic structure, composition, corrosion resistance, and withstand voltage were investigated using various analytical equipment and electrochemical measurements. When the electrolyte containing alcohol was used, the initial bending voltage was higher than that observed using the basic electrolyte without alcohol addition, as was the oscillation voltage during the PEO process. For a given amount of electricity supplied, the addition of alcohol into the basic electrolyte tended to increase the thickness and corrosion resistance of PEO films formed while effectively reducing surface roughness. In particular, the addition of a polyhydric alcohol (i.e., ethylene glycol and glycerol) could act not only as a leveler for the formation of compact film but also as an enhancer for film qualities, such as corrosion resistance and withstand voltage. The patterns observed for Na3PO4-based electrolyte containing alcohol also hold for Na2SiO3-based electrolyte containing alcohol.

Alcohol used as an additive could act not only as a leveler for the formation of compact film but also as an enhancer for film qualities, such as corrosion resistance and withstand voltage.  相似文献   
99.

Purposes

The purpose of this study was to show the clinical features of up-front surgery of the primary tumor in asymptomatic patients with incurable colorectal PC.

Methods

Forty-six patients that were diagnosed between 1998 and 2007 with asymptomatic colorectal PC who could not be successfully cured by surgery were assessed retrospectively.

Results

A univariate analysis revealed the presence of liver metastases, without the use of oxaliplatin (OX)/irinotecan (IRI) and without a primary tumor resection to be poor prognostic factors for survival (p = 0.044, p = 0.030, p < 0.001, respectively). According to a multivariate analysis, no use of OX/IRI and no primary tumor resection, were found to be independent poor prognostic factors for survival (HR 2.57; p = 0.047, HR 6.62; p = 0.003, respectively). The median survival time of patients treated with and without OX/IRI was 18 and 7 months, respectively. The median survival time of patients with and without primary tumor resection was 10 and 2 months, respectively. The number of patients needing surgical intervention for intestinal obstruction after surgery significantly increased in patients treated with OX/IRI (p = 0.001).

Conclusion

Improvement of survival may be related to widespread use of modern systemic chemotherapy and primary tumor resection. However, an increased number of patients that needed surgery for an intestinal obstruction were observed, even after up-front surgery, when patients were treated with modern systemic chemotherapy.  相似文献   
100.
To explore the renoprotective and anti-inflammatory effects of pravastatin, we analyzed the changes in renal function and urinary monocyte chemoattractant protein-1 (MCP-1) level as a renal tubulointerstitial inflammatory biomarker and serum MCP-1 level as a systemic inflammatory biomarker following the introduction of treatment with 10 mg/day of pravastatin in 10 hyperlipidemic type 2 diabetic patients with normoalbuminuria. Twelve months of the pravastatin treatment did not affect urinary levels of albumin, transferrin, N-acetylglucosaminidase, or MCP-1 in the hyperlipidemic diabetic patients, whereas the treatment significantly reduced serum levels of MCP-1 in the patients. The pravastatin treatment effectively lowered low-density lipoprotein cholesterol (LDL-C) levels in the hyperlipidemic diabetic patients to levels nearly to those in 11 non-hyperlipidemic type 2 diabetic patients with normoalbuminuria. Interestingly, serum MCP-1 levels were significantly lower in the hyperlipidemic patients treated with pravastatin than in the non-hyperlipidemic patients. No significant correlation was observed between serum LDL-C and MCP-1 levels in all the data in the hyperlipidemic patients before and after the pravastatin treatment and in the non-hyperlipidemic patients. These results collectively indicate that pravastatin may ameliorate systemic vascular inflammation rather than local renal inflammation in hyperlipidemic type 2 diabetic patients with normoalbuminuria, independent of its cholesterol-lowering effects.  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