全文获取类型
收费全文 | 112786篇 |
免费 | 1951篇 |
国内免费 | 2441篇 |
出版年
2024年 | 31篇 |
2023年 | 264篇 |
2022年 | 654篇 |
2021年 | 1146篇 |
2020年 | 764篇 |
2019年 | 977篇 |
2018年 | 12506篇 |
2017年 | 11101篇 |
2016年 | 8240篇 |
2015年 | 1901篇 |
2014年 | 1787篇 |
2013年 | 1857篇 |
2012年 | 6065篇 |
2011年 | 14329篇 |
2010年 | 12870篇 |
2009年 | 9029篇 |
2008年 | 10777篇 |
2007年 | 12161篇 |
2006年 | 1072篇 |
2005年 | 1138篇 |
2004年 | 1460篇 |
2003年 | 1456篇 |
2002年 | 1141篇 |
2001年 | 577篇 |
2000年 | 479篇 |
1999年 | 347篇 |
1998年 | 215篇 |
1997年 | 263篇 |
1996年 | 200篇 |
1995年 | 189篇 |
1994年 | 168篇 |
1993年 | 158篇 |
1992年 | 202篇 |
1991年 | 180篇 |
1990年 | 153篇 |
1989年 | 105篇 |
1988年 | 107篇 |
1987年 | 100篇 |
1986年 | 63篇 |
1985年 | 65篇 |
1984年 | 50篇 |
1983年 | 64篇 |
1982年 | 23篇 |
1981年 | 16篇 |
1980年 | 15篇 |
1972年 | 249篇 |
1971年 | 280篇 |
1965年 | 29篇 |
1962年 | 24篇 |
1944年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 56 毫秒
961.
962.
963.
Yuan Yang Fan Zhang Laura Skrip Han Lei Yang Wang Dayi Hu Rongjing Ding 《Molecular biology reports》2013,40(3):2589-2598
The potential relationship between Interleukin-6 (IL-6) gene polymorphisms and coronary artery disease (CAD) has been widely investigated. However, study findings on the ?174 G/C and ?572 G/C variants remain inconsistent and somewhat controversial. The present meta-analysis was conducted in an attempt to provide a more robust synthesis conclusion. PubMed and Embase were used to search for all relevant studies published on or before May 22, 2012. A total of 19 studies were ultimately included in the analysis. Overall combined risk was calculated with fixed or random-effects models. Subgroup and sensitivity analyses were performed. Among the included studies, no statistically significant differences were found between controls and CAD cases for the G allele contrasts of the ?174 G/C and ?572 G/C polymorphisms. The co-dominant genetic model was evaluated for the ?174 G/C polymorphism. A significant association was detected using GG versuss CC (OR = 0.801, 95 % CI: [0.652, 0.983], P = 0.034). However, the association was not obviously in subgroup analysis by ethnicity. The recessive genetic model was evaluated for the ?572 G/C polymorphism. The relationship between ?572 G/C polymorphism and CAD risk was only found to be significant in Asian populations (random-effects: OR = 1.908, 95 % CI: [1.016, 3.581], P = 0.044) using GG versus GC+CC. No obvious publication bias was found by Begg’s funnel plots and the Egger’s linear regression test (P = 0.315 for ?174 G/C polymorphism and P = 0.118 for ?572 G/C polymorphism). Our study indicated that the association between the IL-6 gene and CAD risk was mild and moderate for the ?174 G/C and ?572 G/C polymorphisms. However, this relationship requires additional investigation through well-designed studies with larger sample sizes. 相似文献
964.
Most people are aware that outdoor air pollution can damage their health, but many do not know that indoor air pollution can also exhibit significant negative health effects. Fungi parasitizing in air conditioning and ventilation systems can be one of indoor air pollution sources. Aflatoxin produced by Aspergillus flavus (A. flavus) became a central focus of indoor air pollution, especially in farmer markets. Therefore we developed an early warning system, Health Risk Assessment System, to estimate the growth rate of A. flavus, predict the amount of aflatoxin and provide early warning information. Firstly, the growth of A. flavus and the production of aflatoxin under different conditions were widely obtained through a comprehensive literature review. Secondly, three mathematical models were established to predict the A. flavus colony growth rate, lag phase duration and aflatoxin content, as functions of temperature and water activity based on present studies. Finally, all the results were evaluated by the user-supplied data using PHP programming language. We utilized the web page to show the results and display warning information. The JpGraph library was used to create a dynamic line chart, refreshing the warning information dynamically in real-time. The HARS provides accurate information for early warning purposes to let us take timely steps to protect ourselves. 相似文献
965.
Li-nian Huang Dong-sheng Wang Yu-qing Chen Cheng-ling Zhao Bei-lei Gong An-bang Jiang Wei Jia Feng-dan Hu 《Molecular biology reports》2013,40(2):917-924
Among new biological markers that could become useful prognostic factors for non-small cell lung cancer (NSCLC). Survivin is one of the most commonly over-expressed oncogenes, however, its role in NSCLC remains controversial. We performed a systematic review of the literature with meta-analysis to clarify this issue. Electronic databases were used to identify published studies before August 2011. Pooled hazard ratio (HR) with 95 % confidence interval (95 % CI) was used to estimate the strength of the association of survivin expression with survival of NSCLC patients. Heterogeneity and publication bias were also assessed. Overall 29 relevant published studies including 2,517 lung cancer patients were identified from electronic databases. We found that overexpression of survivin in NSCLC patients might be a poor prognostic factor for survival 1.95 (95 % CI: 1.65-2.29; P < 0.001). Heterogeneity testing indicated that there was heterogeneity among studies. When stratified by histology types, the heterogeneity was absent. We should point out that the publication bias may partly account for the result, but the conclusion might not be affected deeply by the publication bias. When we accounted for publication bias using the trim and fill method, the results remained significant (HR = 1.71, 95 % CI: 1.44–2.02, P < 0.001), suggesting the stability of our results. Therefore, our study suggested that survivin overexpression had a poor prognosis value in patients with NSCLC. 相似文献
966.
Sha Lu Changming Lu Junmin Zhang Yongxuan Hu Xiqing Li Liyan Xi 《Mycopathologia》2013,175(5-6):489-495
Chromoblastomycosis is one of the most frequent chronic infections caused by melanized fungi. In order to evaluate the clinical characteristics of chromoblastomycosis in Mainland China, we performed an evidence-based review of published literature. PubMed and Chinese-language database of CNKI, VIP and Wanfang data during January 1990–August 2011 were searched. Epidemiology, clinical features, laboratory findings, therapy and prognosis were analyzed. Cladophialophora carrionii was the most common causative agent in the north of the Mainland China, and Fonsecaea monophora and F. pedrosoi were the most common agents in the southern part of the Mainland China. Infection commonly initiated after the etiologic agents gain entrance through puncture wounds and more common involved extremities of the males. Skin lesions were found in different sites, like the extremities, buttocks, trunk and face, and presented diversity morphology. There were about seven different clinical types found in Mainland China: plaque type, tumoral type, cicatricial type, verrucous type, pseudo-vacuole type, eczymatous type and mixed type of lesions. The success of treatment for chromoblastomycosis was related to the causative agent, the clinical form and severity of the lesions. Most of the patients could be treated successfully with the physical treatment, chemotherapy and/or combination therapy. The itraconazole, terbinafine or a combination of both were commonly medication for these mycosis patients. Physical methods were usually indicated to support chemotherapy with some severe forms and long-lasting cases. Photodynamic therapy has been extended from the oncological field to that of antimicrobial chemotherapy in these years. We applied it on some recalcitrant cases of chromoblastomycosis and found its good clinical response, and hopeful it could be a promising therapy in near future. 相似文献
967.
Zhongsheng Tong Sharon C.-A. Chen Liuqing Chen Bilin Dong Ruoyu Li Zhimin Hu Ping Jiang Dongsheng Li Yiqun Duan 《Mycopathologia》2013,175(3-4):301-306
We report a case of subcutaneous phaeohyphomycosis due to Phialophora verrucosa in a 64-year-old Chinese farmer suffering from CD4+ lymphopenia. He presented with diffuse and infiltrated plaques involving the entire face including the eyes, neck, occiput, and extending to the dorsal regions of his torso. The patient is notable for the discrete multifocal nature of the illness in the absence of disseminated infection and rarity of P. verrucosa as a cause of subcutaneous phaeohyphomycosis. 相似文献
968.
The objective of this study is to quantitatively derive a more precise estimation of the association between X-ray repair cross-complementing group 1 (XRCC1) gene polymorphisms and differentiated thyroid carcinoma risk. A comprehensive literature search of three databases was conducted. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated with fixed-effect models and random-effect models when appropriate. Overall, no association of the XRCC1 Arg399Gln, Arg280His, and Arg194Trp polymorphisms with differentiated thyroid carcinoma risk was found. In subgroup analyses, a decreased differentiated thyroid carcinoma risk was observed among Caucasians (Gln vs. Arg, OR = 0.86, 95% CI = 0.77–0.96, P = 0.343 for heterogeneity; Gln/Arg vs. Arg/Arg, OR = 0.84, 95% CI = 0.71–0.98, P = 0.229 for heterogeneity; Gln/Gln vs. Arg/Arg, OR = 0.77, 95% CI = 0.60–0.99, P = 0.477 for heterogeneity; dominant genetic model, OR = 0.82, 95% CI = 0.71–0.95, P = 0.272 for heterogeneity), not among Asians. No publication bias was observed. Our results suggest that XRCC1 Arg399Gln polymorphism is not associated with differentiated thyroid carcinoma risk, while a decreased risk is observed among Caucasian population. 相似文献
969.
970.
Arihiro Osanai Sheng‐Jun Li Krisana Asano Hiroshi Sashinami Dong‐Liang Hu Akio Nakane 《Microbiology and immunology》2013,57(4):253-262
The role of fibronectin binding protein A (FbpA) in Listeria monocytogenes infection and its pathogenesis were studied in vivo and in vitro by constructing a fbpA‐deficient mutant of L. monocytogenes (ΔfbpA). In vivo, ΔfbpA was less pathogenic in mutant mice than was wild‐type L. monocytogenes. FbpA did not affect the amounts of various virulence‐determining factors, including internalin B and listeriolysin O. However, adherence to, and invasion of, mouse hepatocytes by the ΔfbpA mutant were reduced. In contrast, adherence to, but not invasion of, the ΔfbpA mutant to macrophages was attenuated. Fibronectin contributed to the efficient adherence and invasion of wild‐type L. monocytogenes, but not to those of the ΔfbpA mutant. Attenuation of adhesion and uptake of the ΔfbpA mutant were reversed by overexpression of FbpA in it. FbpA was not involved in intracellular growth, autophagy induction or actin tail formation. Thus, the present findings clearly show that FbpA acts as an important adhesion molecule of L. monocytogenes, especially regarding hepatocytes, without modulating the expression of other virulence factors that have been implicated in the pathogenesis of L. monocytogenes infection. 相似文献