全文获取类型
收费全文 | 4314篇 |
免费 | 285篇 |
国内免费 | 2篇 |
出版年
2023年 | 17篇 |
2022年 | 41篇 |
2021年 | 61篇 |
2020年 | 55篇 |
2019年 | 54篇 |
2018年 | 78篇 |
2017年 | 79篇 |
2016年 | 142篇 |
2015年 | 200篇 |
2014年 | 249篇 |
2013年 | 283篇 |
2012年 | 355篇 |
2011年 | 313篇 |
2010年 | 209篇 |
2009年 | 167篇 |
2008年 | 241篇 |
2007年 | 258篇 |
2006年 | 228篇 |
2005年 | 214篇 |
2004年 | 221篇 |
2003年 | 205篇 |
2002年 | 157篇 |
2001年 | 45篇 |
2000年 | 27篇 |
1999年 | 47篇 |
1998年 | 51篇 |
1997年 | 45篇 |
1996年 | 46篇 |
1995年 | 29篇 |
1994年 | 46篇 |
1993年 | 37篇 |
1992年 | 47篇 |
1991年 | 25篇 |
1990年 | 25篇 |
1989年 | 25篇 |
1988年 | 24篇 |
1987年 | 16篇 |
1986年 | 29篇 |
1985年 | 14篇 |
1984年 | 19篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1979年 | 16篇 |
1978年 | 8篇 |
1977年 | 14篇 |
1976年 | 8篇 |
1973年 | 7篇 |
1972年 | 7篇 |
排序方式: 共有4601条查询结果,搜索用时 390 毫秒
971.
972.
Danuta Witkowska Aleksandra Wilczak Regina Stempniewicz Marta Pasławska Michał Piegza 《Biocontrol Science and Technology》2016,26(12):1591-1604
Agriculture by-products were applied to proliferate biomass of Trichoderma atroviride TRS40 in solid state fermentation (SSF) cultures. The culture media overgrown with mycelium together with conidia were preserved by fluidised bed drying at various temperatures (50°C, 60°C and 70°C) and the received biopreparations were stored for 12 months. In order to determine the suitability of TRS40 in the production of biopreparations, the influence of preservation process and storage time on their survivability was examined. The three-component mixture proved more effective in the SSF cultures, ensuring TRS40 count at 6.07?×?109?CFU/g?dm, which was ca. 6 times higher than in the mono-component medium. TRS40 survivability after preservation at various temperatures ranged from 40.4% to 100%, regardless of carrier type. In turn, after 12-month storage of the biopreparations produced on the three-component medium, regardless of drying temperature, the number of viable cells ranged from 2.43?×?108 to 2.49?×?108?CFU/g?dm. Furthermore, selected parameters of growth kinetics in the Bioscreen C system were determined. The storage time of biopreparations had various effects on growth kinetic parameters. In addition, the preserved preparations based on the TRS40 retained their capability for biosynthesis of hydrolases, even after 12 months of storage. 相似文献
973.
974.
Frank?Qian Ye?Feng Yonglan?Zheng Temidayo?O.?Ogundiran Oladosu?Ojengbede Wei?Zheng William?Blot Christine?B.?Ambrosone Esther?M.?John Leslie?Bernstein Jennifer?J.?Hu Regina?G.?Ziegler Sarah?Nyante Elisa?V.?Bandera Sue?A.?Ingles Michael?F.?Press Katherine?L.?Nathanson Anselm?Hennis Barbara?Nemesure Stefan?Ambs Laurence?N.?Kolonel Olufunmilayo?I.?Olopade Christopher?A.?Haiman Dezheng?HuoEmail author 《Human genetics》2016,135(10):1145-1159
MicroRNAs (miRNA) regulate breast biology by binding to specific RNA sequences, leading to RNA degradation and inhibition of translation of their target genes. While germline genetic variations may disrupt some of these interactions between miRNAs and their targets, studies assessing the relationship between genetic variations in the miRNA network and breast cancer risk are still limited, particularly among women of African ancestry. We systematically put together a list of 822 and 10,468 genetic variants among primary miRNA sequences and 38 genes in the miRNA biogenesis pathway, respectively; and examined their association with breast cancer risk in the ROOT consortium which includes women of African ancestry. Findings were replicated in an independent consortium. Logistic regression was used to estimate the odds ratio (OR) and 95 % confidence intervals (CI). For overall breast cancer risk, three single-nucleotide polymorphisms (SNPs) in miRNA biogenesis genes DROSHA rs78393591 (OR = 0.69, 95 % CI: 0.55–0.88, P = 0.003), ESR1 rs523736 (OR = 0.88, 95 % CI: 0.82–0.95, P = 3.99 × 10?4), and ZCCHC11 rs114101502 (OR = 1.33, 95 % CI: 1.11–1.59, P = 0.002), and one SNP in primary miRNA sequence (rs116159732 in miR-6826, OR = 0.74, 95 % CI: 0.63–0.89, P = 0.001) were found to have significant associations in both discovery and validation phases. In a subgroup analysis, two SNPs were associated with risk of estrogen receptor (ER)-negative breast cancer, and three SNPs were associated with risk of ER-positive breast cancer. Several variants in miRNA and miRNA biogenesis pathway genes were associated with breast cancer risk. Risk associations varied by ER status, suggesting potential new mechanisms in etiology. 相似文献
975.
Incretinomimetic and Insulinomimetic Effect of (2E)‐N′‐(1′‐Naphthyl)‐3,4,5‐Trimethoxybenzohydrazide for Glycemic Homeostasis
下载免费PDF全文
![点击此处可从《Journal of cellular biochemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
976.
Nogueira Angélica Maria Ferreira Adésio da Silva Ferreira Marcia Flores 《Plant Molecular Biology Reporter》2016,34(1):249-256
Plant Molecular Biology Reporter - Myrtaceae has many fruit-bearing species of economic and ecological relevance worldwide, but with microsatellite molecular markers (simple sequence repeats, SSR)... 相似文献
977.
Synthesis and Antileishmanial Activity of Natural Dehydrodieugenol and Its Mono‐ and Dimethyl Ethers
下载免费PDF全文
![点击此处可从《化学与生物多样性》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Luis Cezar Rodrigues José Maria Barbosa‐Filho Marcia Rosa de Oliveira Patrícia Lima do Nascimento Néris Flávio Valadares Pereira Borges Roberto Mioso 《化学与生物多样性》2016,13(7):870-874
The study of chemistry of naturally occurring compounds and the synthesis of their derivatives is fundamentally important for the development of new drugs. In this work, dehydrodieugenol (DHDE) was obtained through oxidative coupling of eugenol, promoted by an aqueous mixture of potassium ferricyanide (K3[Fe(CN)6]) and NH3 · H2O. The partial methoxylation of DHDE with MeI and K2CO3 mainly resulted in the molecular‐shaped monomethyl ether (DHDE‐1MeO) and its dimethyl ether derivative (DHDE‐2MeO). The products from the reactions were characterized by 1H‐ and 13C‐NMR spectroscopy. Additionally, these studies have reported the antileishmanial activity of DHDE against Leishmania amazonensis (IC50 value of 42.20 μg ml?1) and shown that partial methoxylation of DHDE results in a significant increase in its antiparasitic activity (IC50 value of 13.68 μg ml?1). Based on in vitro bioassays, DHDE‐1MeO has shown the highest leishmanicidal activity in promastigota form. Production by direct one‐step synthesis of this monomethoxylated compound can be considered to be a cost‐effective and environmentally friendly method with a short reaction time. 相似文献
978.
The use of parasites as biological tags for discrimination of fish stocks has become a commonly used approach in fisheries management. Metazoan parasite community analysis and anisakid nematode population genetics based on a mitochondrial cytochrome marker were applied in order to assess the usefulness of the two parasitological methods for stock discrimination of beaked redfish Sebastes mentella of three fishing grounds in the North East Atlantic. Multivariate, model-based approaches demonstrated that the metazoan parasite fauna of beaked redfish from East Greenland differed from Tampen, northern North Sea, and Bear Island, Barents Sea. A joint model (latent variable model) was used to estimate the effects of covariates on parasite species and identified four parasite species as main source of differences among fishing grounds; namely Chondracanthus nodosus, Anisakis simplex s.s., Hysterothylacium aduncum, and Bothriocephalus scorpii. Due to its high abundance and differences between fishing grounds, Anisakis simplex s.s. was considered as a major biological tag for host stock differentiation. Whilst the sole examination of Anisakis simplex s.s. on a population genetic level is only of limited use, anisakid nematodes (in particular, A. simplex s.s.) can serve as biological tags on a parasite community level. This study confirmed the use of multivariate analyses as a tool to evaluate parasite infra-communities and to identify parasite species that might serve as biological tags. The present study suggests that S. mentella in the northern North Sea and Barents Sea is not sub-structured. 相似文献
979.
Sarah V. Maifeld Bodrey Ro Hoyin Mok Marla Chu Li Yu Ryan Yamagata Tansy Leonardson Vera Chio Bandita Parhy Samuel Park Marcia Carlson Shushil Machhi Nancy Ulbrandt Ann R. Falsey Edward E. Walsh C. Kathy Wang Mark T. Esser Fengrong Zuo 《PloS one》2016,11(4)
Sensitive and precise serology assays are needed to measure the humoral response to antigens of respiratory syncytial virus (RSV) following natural infection or vaccination. We developed and evaluated a collection of electrochemiluminescent (ECL) serology assays using four RSV antigens (F, N, Ga and Gb). To assess the merits of ECL technology, the four ECL serology assays were evaluated using a well-characterized “gold standard” panel of acute and convalescent serum samples from fifty-nine RSV-positive and thirty RSV-negative elderly subjects (≥65 years old). The combined results from the four ECL assays demonstrated good concordance to the “gold standard” diagnosis, reaching 95% diagnostic sensitivity and 100% diagnostic specificity. Additionally, a combination of ECL assays provided higher diagnostic sensitivity than a commercially available diagnostic ELISA or cell-based microneutralization assay. In summary, these data demonstrate the advantages of using ECL-based serology assays and highlight their use as a sensitive diagnostic approach to detect recent RSV infection in an elderly population. 相似文献
980.
Lan B. Hoang-Minh Loic P. Deleyrolle Nariaki S. Nakamura Alexander K. Parker Regina T. Martuscello Brent A. Reynolds Matthew R. Sarkisian 《Translational oncology》2016,9(5):392-402
A better understanding of the molecules implicated in the growth and survival of glioblastoma (GBM) cells and their response to temozolomide (TMZ), the standard-of-care chemotherapeutic agent, is necessary for the development of new therapies that would improve the outcome of current GBM treatments. In this study, we characterize the role of pericentriolar material 1 (PCM1), a component of centriolar satellites surrounding centrosomes, in GBM cell proliferation and sensitivity to genotoxic agents such as TMZ. We show that PCM1 is expressed around centrioles and ciliary basal bodies in patient GBM biopsies and derived cell lines and that its localization is dynamic throughout the cell cycle. To test whether PCM1 mediates GBM cell proliferation and/or response to TMZ, we used CRISPR/Cas9 genome editing to generate primary GBM cell lines depleted of PCM1. These PCM1-depleted cells displayed reduced AZI1 satellite protein localization and significantly decreased proliferation, which was attributable to increased apoptotic cell death. Furthermore, PCM1-depleted lines were more sensitive to TMZ toxicity than control lines. The increase in TMZ sensitivity may be partly due to the reduced ability of PCM1-depleted cells to form primary cilia, as depletion of KIF3A also ablated GBM cells'' ciliogenesis and increased their sensitivity to TMZ while preserving PCM1 localization. In addition, the co-depletion of KIF3A and PCM1 did not have any additive effect on TMZ sensitivity. Together, our data suggest that PCM1 plays multiple roles in GBM pathogenesis and that associated pathways could be targeted to augment current or future anti-GBM therapies. 相似文献