全文获取类型
收费全文 | 5515篇 |
免费 | 472篇 |
国内免费 | 2篇 |
出版年
2022年 | 16篇 |
2021年 | 85篇 |
2020年 | 66篇 |
2019年 | 76篇 |
2018年 | 112篇 |
2017年 | 95篇 |
2016年 | 147篇 |
2015年 | 249篇 |
2014年 | 253篇 |
2013年 | 398篇 |
2012年 | 415篇 |
2011年 | 400篇 |
2010年 | 281篇 |
2009年 | 226篇 |
2008年 | 315篇 |
2007年 | 362篇 |
2006年 | 317篇 |
2005年 | 300篇 |
2004年 | 236篇 |
2003年 | 264篇 |
2002年 | 279篇 |
2001年 | 52篇 |
2000年 | 36篇 |
1999年 | 53篇 |
1998年 | 64篇 |
1997年 | 34篇 |
1996年 | 38篇 |
1995年 | 35篇 |
1994年 | 35篇 |
1993年 | 28篇 |
1992年 | 30篇 |
1990年 | 24篇 |
1989年 | 24篇 |
1988年 | 22篇 |
1987年 | 15篇 |
1986年 | 26篇 |
1985年 | 14篇 |
1984年 | 28篇 |
1983年 | 22篇 |
1982年 | 27篇 |
1981年 | 17篇 |
1980年 | 17篇 |
1979年 | 18篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 17篇 |
1974年 | 16篇 |
1971年 | 15篇 |
1970年 | 19篇 |
1968年 | 15篇 |
排序方式: 共有5989条查询结果,搜索用时 15 毫秒
1.
Travis Park Felix G. Marx Erich M. G. Fitzgerald Alistair R. Evans 《Journal of morphology》2017,278(6):801-809
The pygmy right whale, Caperea marginata , is the least understood extant baleen whale (Cetacea, Mysticeti). Knowledge on its basic anatomy, ecology, and fossil record is limited, even though its singular position outside both balaenids (right whales) and balaenopteroids (rorquals + grey whales) gives Caperea a pivotal role in mysticete evolution. Recent investigations of the cetacean cochlea have provided new insights into sensory capabilities and phylogeny. Here, we extend this advance to Caperea by describing, for the first time, the inner ear of this enigmatic species. The cochlea is large and appears to be sensitive to low‐frequency sounds, but its hearing limit is relatively high. The presence of a well‐developed tympanal recess links Caperea with cetotheriids and balaenopteroids, rather than balaenids, contrary to the traditional morphological view of a close Caperea‐balaenid relationship. Nevertheless, a broader sample of the cetotheriid Herpetocetus demonstrates that the presence of a tympanal recess can be variable at the specific and possibly even the intraspecific level. 相似文献
2.
The aim of this review and meta-analysis was to critically determine the possible effects of different cooling applications, compared to non-cooling, passive post-exercise strategies, on recovery characteristics after various, exhaustive exercise protocols up to 96 hours (hrs). A total of n = 36 articles were processed in this study. To establish the research question, the PICO-model, according to the PRISMA guidelines was used. The Cochrane’s risk of bias tool, which was used for the quality assessment, demonstrated a high risk of performance bias and detection bias. Meta-analyses of subjective characteristics, such as delayed-onset muscle soreness (DOMS) and ratings of perceived exertion (RPE) and objective characteristics like blood plasma markers and blood plasma cytokines, were performed. Pooled data from 27 articles revealed, that cooling and especially cold water immersions affected the symptoms of DOMS significantly, compared to the control conditions after 24 hrs recovery, with a standardized mean difference (Hedges’ g) of -0.75 with a 95% confidence interval (CI) of -1.20 to -0.30. This effect remained significant after 48 hrs (Hedges’ g: -0.73, 95% CI: -1.20 to -0.26) and 96 hrs (Hedges’ g: -0.71, 95% CI: -1.10 to -0.33). A significant difference in lowering the symptoms of RPE could only be observed after 24 hrs of recovery, favouring cooling compared to the control conditions (Hedges’ g: -0.95, 95% CI: -1.89 to -0.00). There was no evidence, that cooling affects any objective recovery variable in a significant way during a 96 hrs recovery period. 相似文献
3.
4.
Karlheinz Grillitsch Pablo Tarazona Lisa Klug Tamara Wriessnegger Günther Zellnig Erich Leitner Ivo Feussner Günther Daum 《生物化学与生物物理学报:生物膜》2014
Despite similarities of cellular membranes in all eukaryotes, every compartment displays characteristic and often unique features which are important for the functions of the specific organelles. In the present study, we biochemically characterized the plasma membrane of the methylotrophic yeast Pichia pastoris with emphasis on the lipids which form the matrix of this compartment. Prerequisite for this effort was the design of a standardized and reliable isolation protocol of the plasma membrane at high purity. Analysis of isolated plasma membrane samples from P. pastoris revealed an increase of phosphatidylserine and a decrease of phosphatidylcholine compared to bulk membranes. The amount of saturated fatty acids in the plasma membrane was higher than in total cell extracts. Ergosterol, the final product of the yeast sterol biosynthetic pathway, was found to be enriched in plasma membrane fractions, although markedly lower than in Saccharomyces cerevisiae. A further characteristic feature of the plasma membrane from P. pastoris was the enrichment of inositol phosphorylceramides over neutral sphingolipids, which accumulated in internal membranes. The detailed analysis of the P. pastoris plasma membrane is discussed in the light of cell biological features of this microorganism especially as a microbial cell factory for heterologous protein production. 相似文献
5.
Aurélien Sokal Pascal Chappert Giovanna Barba-Spaeth Anais Roeser Slim Fourati Imane Azzaoui Alexis Vandenberghe Ignacio Fernandez Annalisa Meola Magali Bouvier-Alias Etienne Crickx Asma Beldi-Ferchiou Sophie Hue Laetitia Languille Marc Michel Samia Baloul France Noizat-Pirenne Marine Luka Matthieu Mahévas 《Cell》2021,184(5):1201-1213.e14
6.
Sydney X. Lu Emma De Neef James D. Thomas Erich Sabio Benoit Rousseau Mathieu Gigoux David A. Knorr Benjamin Greenbaum Yuval Elhanati Simon J. Hogg Andrew Chow Arnab Ghosh Abigail Xie Dmitriy Zamarin Daniel Cui Caroline Erickson Michael Singer Hana Cho Robert K. Bradley 《Cell》2021,184(15):4032-4047.e31
7.
Erich Jost 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1970,40(6):251-256
Zusammenfassung Bei Kreuzungen zwischen Culex pipiens-Populationen verschiedener geographischer Herkunft werden drei Kreuzungstypen festgestellt: normale Kreuzbarkeit, reduzierte Kreuzbarkeit und Inkompatibilität (Nichtkreuzbarkeit). Die drei Kreuzungstypen sind mit Hilfe der Embryonierungsrate, der Schlüpfrate und der entstehenden Nachkommenschaft gegeneinander abgrenzbar. Bei Inkompatibilität sind 99.9% der sich entwickelnden Embryonen letal und etwa 0.1% der Tiere schlüpfen und sind fertile, diploide Weibchen. Die Aktivierung des Eies erfolgt durch das Spermium. Es liegt induzierte, meiotische Parthenogenese vor. Die diploiden, parthenogenetischen Weibchen gehen aus einer Oocyte 2. Ordnung oder aus Teilungsprodukten einer Oocyte 2. Ordnung hervor. Bei den letalen, haploiden Embryonen beteiligt sich das Spermium nicht am Aufbau des Embryos.
Teil einer Dissertation der Math.-Nat. Fakultät der Universität Mainz
Danksagung: Herrn Prof. Dr. H. Laven danke ich für die Bereitstellung des Untersuchungsmaterials sowie für die Anregungen bei der Durchführung der Arbeit.
Angenommen durch H. Stubbe 相似文献
Genetic investigations on the incompatibility in the Culex pipiens complex
Summary In crosses between populations of the mosquito Culex pipiens of different geographical origin three crossing types have been found (1) crosses with normal offspring (2) crosses with reduced offspring and (3) crosses that show almost total incompatibility. In the case of incompatible crosses 99.9% of the developing embryos are lethal and only about 0.1% of the embryos hatch and develop into fertile diploid females. The origin of the exceptional diploid females has been investigated by means of the marker genes Kuf, r, w, var, y and ru. These females develop from a diploid oocyte or from a diploid nucleus that originated by fusion of the pronucleus and the last polar body. This has been concluded from the frequency of homozygous and heterozygous offspring from heterozygous females, the frequency of equational separation of different genes and the distribution of cross-over gametes in the exceptional females. Based on the genetical data it is argued that induced meiotic parthenogenesis takes place. The sperm does not play any part in the production of the diploid females and the lethal embryos. After the activation of the egg the sperm moves to the center of the egg but it does not succeed to fuse with the pronucleus. As a result the pronucleus starts to develop into a haploid embryo in about 99.9% and only in a few cases is the diploidy restored by a change in the meiotic process in the egg.
Teil einer Dissertation der Math.-Nat. Fakultät der Universität Mainz
Danksagung: Herrn Prof. Dr. H. Laven danke ich für die Bereitstellung des Untersuchungsmaterials sowie für die Anregungen bei der Durchführung der Arbeit.
Angenommen durch H. Stubbe 相似文献
8.
v. Tschermak-Seysenegg Erich 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1944,16(1-3):1-3
Ohne Zusammenfassung 相似文献
9.
10.