全文获取类型
收费全文 | 4045篇 |
免费 | 282篇 |
国内免费 | 2篇 |
专业分类
4329篇 |
出版年
2023年 | 13篇 |
2022年 | 20篇 |
2021年 | 39篇 |
2020年 | 31篇 |
2019年 | 43篇 |
2018年 | 64篇 |
2017年 | 54篇 |
2016年 | 88篇 |
2015年 | 195篇 |
2014年 | 166篇 |
2013年 | 221篇 |
2012年 | 289篇 |
2011年 | 281篇 |
2010年 | 213篇 |
2009年 | 162篇 |
2008年 | 230篇 |
2007年 | 270篇 |
2006年 | 255篇 |
2005年 | 240篇 |
2004年 | 221篇 |
2003年 | 233篇 |
2002年 | 211篇 |
2001年 | 40篇 |
2000年 | 35篇 |
1999年 | 57篇 |
1998年 | 62篇 |
1997年 | 49篇 |
1996年 | 52篇 |
1995年 | 45篇 |
1994年 | 36篇 |
1993年 | 50篇 |
1992年 | 38篇 |
1991年 | 26篇 |
1990年 | 17篇 |
1989年 | 31篇 |
1988年 | 13篇 |
1987年 | 27篇 |
1986年 | 18篇 |
1985年 | 13篇 |
1984年 | 22篇 |
1983年 | 26篇 |
1982年 | 15篇 |
1981年 | 23篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1976年 | 6篇 |
1975年 | 7篇 |
1974年 | 9篇 |
1973年 | 7篇 |
排序方式: 共有4329条查询结果,搜索用时 0 毫秒
901.
Monika Hilker Jens Schwachtje Margarete Baier Salma Balazadeh Isabel Bäurle Sven Geiselhardt Dirk K. Hincha Reinhard Kunze Bernd Mueller‐Roeber Matthias C. Rillig Jens Rolff Tina Romeis Thomas Schmülling Anke Steppuhn Joost van Dongen Sarah J. Whitcomb Susanne Wurst Ellen Zuther Joachim Kopka 《Biological reviews of the Cambridge Philosophical Society》2016,91(4):1118-1133
Experience and memory of environmental stimuli that indicate future stress can prepare (prime) organismic stress responses even in species lacking a nervous system. The process through which such organisms prepare their phenotype for an improved response to future stress has been termed ‘priming’. However, other terms are also used for this phenomenon, especially when considering priming in different types of organisms and when referring to different stressors. Here we propose a conceptual framework for priming of stress responses in bacteria, fungi and plants which allows comparison of priming with other terms, e.g. adaptation, acclimation, induction, acquired resistance and cross protection. We address spatial and temporal aspects of priming and highlight current knowledge about the mechanisms necessary for information storage which range from epigenetic marks to the accumulation of (dormant) signalling molecules. Furthermore, we outline possible patterns of primed stress responses. Finally, we link the ability of organisms to become primed for stress responses (their ‘primability’) with evolutionary ecology aspects and discuss which properties of an organism and its environment may favour the evolution of priming of stress responses. 相似文献
902.
Bernd Rosslenbroich 《Biology & philosophy》2016,31(4):591-601
The essay review summarizes the intention as well as some of the major topics from the book of A. Moreno and M. Mossio and discusses them against the background of recent considerations on the general understanding of organisms. The authors see themselves in the organicist tradition in biology and propose that a new understanding of living beings can be developed around the notion of organismic autonomy, which enables biological systems to maintain themselves in an environment through directed behavior. 相似文献
903.
904.
905.
Nanna H. Vidkjær Bernd Wollenweber Karl-Martin V. Jensen Per L. Ambus Joachim Offenberg Inge S. Fomsgaard 《Journal of Plant Growth Regulation》2016,35(3):803-814
Weaver ants are tropical insects that nest in tree canopies, and for centuries these ants have been used for pest control in tropical orchards. Trees hosting weaver ants might benefit not only from the pest protective properties of these insects but also an additional supply of nutrients from ant feces deposited on the leaves. In a recent study, we demonstrated that Coffea arabica plants hosting Oecophylla smaragdina weaver ants under laboratory conditions experienced enhanced nitrogen availability compared with plants grown without ants. Therefore, the aim of the present study was to further investigate the interactions of weaver ants with the host plants with respect to plant nutrition. Here, we report the identification and quantification of urea, a highly effective foliar nutrient present in the fecal depositions of O. smaragdina. Feces samples obtained from six O. smaragdina colonies were analyzed, and urea concentrations ranging from 1.98 to 31.05 μg/mg ant feces were detected. Subsequently, we investigated the uptake and translocation of 15N2-urea in amounts corresponding to the estimated urea contribution via feces depositions on single host plant leaves under laboratory conditions. The results clearly demonstrated that fecal urea was not only assimilated but also translocated within the plant. This evidence strongly supports the hypothesis that the fecal urea of weaver ants is a source of nitrogen for the host trees. Thus, weaver ant feces likely contribute to an improved nutritional status of ant-hosting trees in tropical orchards, thereby adding value to the use of weaver ants for the biocontrol of insect pests. 相似文献
906.
Dennis Lal Bernd A. Neubauer Mohammad R. Toliat Janine Altmüller Holger Thiele Peter Nürnberg Clemens Kamrath Anne Sch?nzer Thomas Sander Andreas Hahn Michael Nothnagel 《PloS one》2016,11(1)
Massively parallel sequencing of whole genomes and exomes has facilitated a direct assessment of causative genetic variation, now enabling the identification of genetic factors involved in rare diseases (RD) with Mendelian inheritance patterns on an almost routine basis. Here, we describe the illustrative case of a single consanguineous family where this strategy suffered from the difficulty to distinguish between two etiologically distinct disorders, namely the co-occurrence of hereditary hypophosphatemic rickets (HRR) and congenital myopathies (CM), by their phenotypic manifestation alone. We used parametric linkage analysis, homozygosity mapping and whole exome-sequencing to identify mutations underlying HRR and CM. We also present an approximate approach for assessing the probability of co-occurrence of two unlinked recessive RD in a single family as a function of the degree of consanguinity and the frequency of the disease-causing alleles. Linkage analysis and homozygosity mapping yielded elusive results when assuming a single RD, but whole-exome sequencing helped to identify two mutations in two genes, namely SLC34A3 and SEPN1, that segregated independently in this family and that have previously been linked to two etiologically different diseases. We assess the increase in chance co-occurrence of rare diseases due to consanguinity, i.e. under circumstances that generally favor linkage mapping of recessive disease, and show that this probability can increase by several orders of magnitudes. We conclude that such potential co-occurrence represents an underestimated risk when analyzing rare or undefined diseases in consanguineous families and should be given more consideration in the clinical and genetic evaluation. 相似文献
907.
Ignacio Ortea Bernd Roschitzki Rosario López-Rodríguez Eva G. Tomero Juan G. Ovalles Javier López-Longo Inmaculada de la Torre Isidoro González-Alvaro Juan J. Gómez-Reino Antonio González 《PloS one》2016,11(4)
Response to treatment of rheumatoid arthritis shows large inter-individual variability. This heterogeneity is observed with all the anti-rheumatic drugs, including the commonly used TNF inhibitors. It seems that drug-specific and target-specific factors lead individual patients to respond or not to a given drug, although this point has been challenged. The search of biomarkers distinguishing responders from non-responders has included shotgun proteomics of serum, as a previous study of response to infliximab, an anti-TNF antibody. Here, we have used the same study design and technology to search biomarkers of response to a different anti-TNF antibody, adalimumab, and we have compared the results obtained for the two anti-TNF drugs. Search of biomarkers of response to adalimumab included depletion of the most abundant serum proteins, 8-plex isobaric tag for relative and absolute quantitation (iTRAQ) labeling, two-dimensional liquid chromatography fractionation and relative quantification with a hybrid Orbitrap mass spectrometer. With this approach, 264 proteins were identified in all the samples with at least 2 peptides and 95% confidence. Nine proteins showed differences between non-responders and responders (P < 0.05), representing putative biomarkers of response to adalimumab. These results were compared with the previous study of infliximab. Surprisingly, the non-responder/responder differences in the two studies were not correlated (rs = 0.07; P = 0.40). This overall independence with all the proteins showed two identifiable components. On one side, the putative biomarkers of response to either adalimumab or infliximab, which were not shared and showed an inverse correlation (rs = -0.69; P = 0.0023). On the other, eight proteins showing significant non-responder/responder differences in the analysis combining data of response to the two drugs. These results identify new putative biomarkers of response to treatment of rheumatoid arthritis and indicate that they are notably drug-specific. 相似文献
908.
Armin A. Weiser Christian Th?ns Matthias Filter Alexander Falenski Bernd Appel Annemarie K?sbohrer 《PloS one》2016,11(3)
FoodChain-Lab is modular open-source software for trace-back and trace-forward analysis in food-borne disease outbreak investigations. Development of FoodChain-Lab has been driven by a need for appropriate software in several food-related outbreaks in Germany since 2011. The software allows integrated data management, data linkage, enrichment and visualization as well as interactive supply chain analyses. Identification of possible outbreak sources or vehicles is facilitated by calculation of tracing scores for food-handling stations (companies or persons) and food products under investigation. The software also supports consideration of station-specific cross-contamination, analysis of geographical relationships, and topological clustering of the tracing network structure. FoodChain-Lab has been applied successfully in previous outbreak investigations, for example during the 2011 EHEC outbreak and the 2013/14 European hepatitis A outbreak. The software is most useful in complex, multi-area outbreak investigations where epidemiological evidence may be insufficient to discriminate between multiple implicated food products. The automated analysis and visualization components would be of greater value if trading information on food ingredients and compound products was more easily available. 相似文献
909.
Waldemar Adam Franklin Vargas Bernd Epe Dietmar Schiffmann Dieter Wild 《Free radical research》1989,5(4):253-258
Substances of low oxidation potential, which can also make available protons and hydrogen atoms, e.g. phenothiazines. NADH, and ascorbic acid efficiently reduce 1, 2-dioxetanes to their vic-diols by single-electron-transfer; a significant side reaction is catalytic decomposition of dioxetanes into the corresponding ketone fragments 相似文献
910.
The spin trap 5,5-dimethyl-l-pyrroline-l-oxide (DMPO) has been applied to monitor the generation of free oxy-radicals in samples derived from isolated hearts and heart cells. · OH was trapped in the effluent of isolated hearts in the early phase of reperfusion following an ischemia time of only 10min. Radical detection was possible even when the cardioactive DMPO was added to the effluent after draining off the heart, demonstrating that the short-lived · OH was generated by components released from the affected heart. These results support the hypothesis that radicals are of relevance for reperfusion injury.
By omitting antioxidants commonly used for incubation media of cultured cells, it was possible for the first time to demonstrate the formation of · OH in the incubation solution of cardiac cells. 相似文献
By omitting antioxidants commonly used for incubation media of cultured cells, it was possible for the first time to demonstrate the formation of · OH in the incubation solution of cardiac cells. 相似文献