全文获取类型
收费全文 | 4201篇 |
免费 | 342篇 |
国内免费 | 10篇 |
出版年
2023年 | 7篇 |
2022年 | 38篇 |
2021年 | 83篇 |
2020年 | 63篇 |
2019年 | 84篇 |
2018年 | 104篇 |
2017年 | 79篇 |
2016年 | 150篇 |
2015年 | 260篇 |
2014年 | 263篇 |
2013年 | 277篇 |
2012年 | 384篇 |
2011年 | 314篇 |
2010年 | 189篇 |
2009年 | 181篇 |
2008年 | 277篇 |
2007年 | 243篇 |
2006年 | 218篇 |
2005年 | 190篇 |
2004年 | 192篇 |
2003年 | 151篇 |
2002年 | 145篇 |
2001年 | 77篇 |
2000年 | 63篇 |
1999年 | 65篇 |
1998年 | 39篇 |
1997年 | 28篇 |
1996年 | 12篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 26篇 |
1991年 | 28篇 |
1990年 | 16篇 |
1989年 | 26篇 |
1988年 | 24篇 |
1987年 | 23篇 |
1986年 | 23篇 |
1985年 | 16篇 |
1984年 | 15篇 |
1983年 | 9篇 |
1982年 | 14篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1975年 | 13篇 |
1974年 | 10篇 |
1973年 | 8篇 |
排序方式: 共有4553条查询结果,搜索用时 15 毫秒
141.
Jae-Myun Ryu Gwi Yeong Jang Dongsun Park Koan Sik Woo Tae Myoung Kim Heon Sang Jeong 《Bioscience, biotechnology, and biochemistry》2013,77(12):2101-2108
ABSTRACTBenign prostatic hyperplasia (BPH) is commonly observed in men > 50 years worldwide. Phytotherapy is one of the many treatment options. Sorghum (Sorghum bicolor L.) contains various health-improving phytochemicals with antioxidant and inhibitory activities on cell proliferation, both in vitro and in vivo. To confirm the effects of Donganme sorghum ethyl-acetate extract (DSEE) on BPH, we induced BPH in Spragye–Dawley rats using exogenous testosterone. We measured prostate weight, examined prostrates histopathologically, and analyzed mRNAs associated with male hormones and proteins associated with cell proliferation in the prostate. DSEE inhibited weight gain of the prostate; decreased mRNA expressions of androgen receptor and 5α-reductase II; and improved histopathological symptoms, the protein-expressed ratio of Bax/Bcl-2, and the oxidative status of BPH induced by testosterone in SD rats. Therefore, DSEE may have potential as a preventive or therapeutic agent against BPH. 相似文献
142.
Eui-Baek Byun Woo-Young Park Woo Sik Kim Ha-Yeon Song Nak-Yun Sung 《Bioscience, biotechnology, and biochemistry》2013,77(12):2149-2157
ABSTRACTPhenolic compounds isolated from pepper (Capsicum annum) have been demonstrated to have neuroprotective effects, whereas the physiological properties of Capsicum annuum var. abbreviatum (CAA) have not been studied. Thus, we investigate the chemical composition and neuroprotective activity of CAA extract (CAAE) in HT22 hippocampus cells against H2O2-induced neurotoxicity. CAAE treatment resulted in a significant protection of H2O2-exposed HT22, this protection ultimately occurred through an inhibition of MDA and ROS levels and an induction of SOD activity. Furthermore, CAAE treatment reduced H202-induced apoptosis though decreasing the expression of pro-apoptotic factors (Bax, cytochrome c, and cleaved caspases-3) while increasing the expression of the anti-apoptotic factors (Bcl-2), as well as the accumulation of nucleus-Nrf2-mediated HO-1 signaling. Interestingly, CAAE has a high concentration of unique phenolic compositions (chlrogenic acid, tangeretin, etc.) than other capsicum annum extracts. Altogether, these findings suggest that CAAE can be a useful natural resource for alleviating neurodegenerative diseases. 相似文献
143.
Jeong Woo Lee Sangchul Lee Jin-Nyoung Ho Je-In Youn Seok-Soo Byun 《Bioscience, biotechnology, and biochemistry》2013,77(12):2265-2271
ABSTRACTAs standard second-line regimen has not been established for patients who are refractory to or relapse with cisplatin-based chemotherapy, an effective class of novel chemotherapeutic agents is needed for cisplatin-resistant bladder cancer. Recent publications reported that MutT homolog 1 (MTH1) inhibitors suppress tumor growth and induce impressive therapeutic responses in a variety of human cancer cells. Few studies investigated the cytotoxic effects of MTH1 inhibitors in human bladder cancer. Accordingly, we investigated the antitumor effects and the possible molecular mechanisms of MTH1 inhibitors in cisplatin-sensitive (T24) and – resistant (T24R2) human bladder cancer cell lines. These results suggest that TH588 or TH287 may induce cancer cell suppression by off-target effects such as alterations in the expression of apoptosis- and cell cycle-related proteins rather than MTH1 inhibition in cisplatin-sensitive and – resistant bladder cancer cells.Abbreviations: MTH: MutT homolog; ROS: reactive oxygen species; CCK-8: cell counting kit-8; DCFH-DA: dichlorofluorescein diacetate; PARP: poly (ADP-ribose) polymerase 相似文献
144.
Download : Download video (36MB) 相似文献
145.
Yong Wang Jae Young Choi Jong Yul Roh Xue Ying Tao Qin Liu Joo Hyun Lee Jae Su Kim Woo Jin Kim Yeon Ho Je 《Entomological Research》2013,43(1):63-69
Baculovirus chitinase gene (chiA) is a late gene essential for liquefying the host insect at a late stage of infection for its hydrolyzing chitin function. In a previous report, baculovirus ChiA has been shown to offer many interesting new opportunities for pest control. Recently, a putative chiA gene was identified in the Korean isolate of the Spodoptera litura nucleopolyhedorvirus (SpliMNPV‐K1) genome. The open reading frame (ORF) contains 1692 nucelotides and encodes a protein of 563 amino acids with a predicted molecular weight of about 62.6 kDa. To study the insecticidal activity of ChiA from SpliMNPV‐K1, we constructed a recombinant AcMNPV, Ap‐SlChiA, which is designed to express the ChiA under the control of a polyhedrin promoter. Western blot analysis indicated that ChiA was successfully expressed by this recombinant virus. Chitinase assay revealed that the chitobiosidase and endochitinase activity of the recombinant virus was 2.5‐ and 3.9‐flods higher than those of wild‐type AcMNPV, respectively. In addition, the recombinant virus showed higher evident insecticidal activity against 3rd instar larvae of Spodotera exigua than that of the AcMNPV. These results suggest that the chiA gene from SpliMNPV‐K1 could be successfully applied to improve pathogenicity of baculoviruses. 相似文献
146.
We examined the structure of the arthropod community among deciduous and coniferous dead woods along the process of wood decay. We collected dead wood‐dwelling arthropods from April 2010 to October 2011 by using a vacuum aspirator and an electric chain saw in three areas (Mt. Woonak, Mt. Wolchul, Mt. Jingang) in Korea. We identified them to species levels and classified them into functional groups. We collected 8792 arthropods (5 classes, 20 orders, 58 families, and 93 species). The species richness and abundance of arthropods increased with the progress of decay in dead woods. The evenness index seemed to be shown at a lower value at late decay stage than at early‐ and mid‐decay stages. The diversity index (H′) in conifers was lower than that in deciduous dead woods at the early decay stage but this situation was reversed at the late decay stage. Arthropod communities of functional groups, except the xylophagous insects, did not differ in the variables, but the proportion of xylophagous insects increased as the decay stages progressed. The abundance of arthropods and xylophagous was statistically significantly different. The patterns generated by non‐metric multidimensional scaling in the overall arthropod community composition revealed that the species composition between study areas were significantly different. We confirmed that dead woods play very important roles as arthropods' habitats. Thus, we suggest that the role of dead woods should be emphasized in the management of forest ecosystems. 相似文献
147.
148.
Eun Hyun Seo Dong Young Lee Jong-Min Lee Jun-Sung Park Bo Kyung Sohn Dong Soo Lee Young Min Choe Jong Inn Woo 《PloS one》2013,8(1)
The conceptual significance of understanding functional brain alterations and cognitive deficits associated with Alzheimer’s disease (AD) process has been widely established. However, the whole-brain functional networks of AD and its prodromal stage, mild cognitive impairment (MCI), are not well clarified yet. In this study, we compared the characteristics of the whole-brain functional networks among cognitively normal (CN), MCI, and AD individuals by applying graph theoretical analyses to [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) data. Ninety-four CN elderly, 183 with MCI, and 216 with AD underwent clinical evaluation and FDG-PET scan. The overall small-world property as seen in the CN whole-brain network was preserved in MCI and AD. In contrast, individual parameters of the network were altered with the following patterns of changes: local clustering of networks was lower in both MCI and AD compared to CN, while path length was not different among the three groups. Then, MCI had a lower level of local clustering than AD. Subgroup analyses for AD also revealed that very mild AD had lower local clustering and shorter path length compared to mild AD. Regarding the local properties of the whole-brain networks, MCI and AD had significantly decreased normalized betweenness centrality in several hubs regionally associated with the default mode network compared to CN. Our results suggest that the functional integration in whole-brain network progressively declines due to the AD process. On the other hand, functional relatedness between neighboring brain regions may not gradually decrease, but be the most severely altered in MCI stage and gradually re-increase in clinical AD stages. 相似文献
149.
Sang Ouk Chin Sang Youl Rhee Suk Chon You-Cheol Hwang In-Kyung Jeong Seungjoon Oh Kyu Jeung Ahn Ho Yeon Chung Jeong-taek Woo Sung-Woon Kim Jin-Woo Kim Young Seol Kim Hong-Yup Ahn 《PloS one》2013,8(3)
Background
The association between sarcopenia and cardiovascular disease (CVD) in elderly people has not been adequately assessed. The aim of this study was to investigate whether CVD is more prevalent in subjects with sarcopenia independent of other well-established cardiovascular risk factors in older Korean adults.Method
This study utilized the representative Korean population data from the Korea National Health and Nutrition Examination Survey (KNHANES) which was conducted in 2009. Subjects older than 65 years of age with appendicular skeletal muscle mass (ASM) determined by dual energy X-ray absorptiometry were selected. The prevalence of sarcopenia in the older Korean adults was investigated, and it was determined whether sarcopenia is associated with CVD independent of other well-known risk factors.Results
1,578 subjects aged 65 years and older with the data for ASM were selected, and the overall prevalence of sarcopenia was 30.3% in men and 29.3% in women. Most of the risk factors for CVD such as age, waist circumference, body mass index, fasting plasma glucose and total cholesterol showed significant negative correlations with the ratio between appendicular skeletal muscle mass and body weight. Multiple logistic regression analysis demonstrated that sarcopenia was associated with CVD independent of other well-documented risk factors, renal function and medications (OR, 1.768; 95% CI, 1.075–2.909, P = 0.025).Conclusions
Sarcopenia was associated with the presence of CVD independent of other cardiovascular risk factors after adjusting renal function and medications. 相似文献150.