全文获取类型
收费全文 | 5378篇 |
免费 | 552篇 |
国内免费 | 2篇 |
出版年
2022年 | 41篇 |
2021年 | 75篇 |
2020年 | 44篇 |
2019年 | 77篇 |
2018年 | 62篇 |
2017年 | 73篇 |
2016年 | 142篇 |
2015年 | 212篇 |
2014年 | 257篇 |
2013年 | 302篇 |
2012年 | 375篇 |
2011年 | 322篇 |
2010年 | 212篇 |
2009年 | 152篇 |
2008年 | 249篇 |
2007年 | 278篇 |
2006年 | 255篇 |
2005年 | 247篇 |
2004年 | 227篇 |
2003年 | 217篇 |
2002年 | 225篇 |
2001年 | 110篇 |
2000年 | 113篇 |
1999年 | 107篇 |
1998年 | 82篇 |
1997年 | 57篇 |
1996年 | 57篇 |
1995年 | 41篇 |
1994年 | 50篇 |
1993年 | 48篇 |
1992年 | 76篇 |
1991年 | 63篇 |
1990年 | 48篇 |
1989年 | 53篇 |
1988年 | 65篇 |
1987年 | 50篇 |
1986年 | 58篇 |
1985年 | 64篇 |
1984年 | 41篇 |
1982年 | 31篇 |
1981年 | 29篇 |
1980年 | 33篇 |
1979年 | 45篇 |
1978年 | 34篇 |
1977年 | 51篇 |
1976年 | 48篇 |
1974年 | 40篇 |
1973年 | 46篇 |
1972年 | 34篇 |
1970年 | 29篇 |
排序方式: 共有5932条查询结果,搜索用时 15 毫秒
1.
Herv Canut Johann Bauer Gerhard Weber 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》1999,722(1-2)
The review focuses on the multiple separating regimes that offers the free flow electrophoresis technique: free flow zone electrophoresis, isoelectric focusing, isotachophoresis, free flow step electrophoresis. Also, the feasibility to apply either interval or continuous flow electrophoresis is evaluated. The free flow zone electrophoresis regime is generally selected for the separation of cells, organelles and membranes while the other regimes find their largest fields of applications in the purification of proteins and peptides. The latter regimes present the highest resolution efficiency. Therefore, a large part of this review is devoted to the applicabilities of these different regimes to the purification of organelles and membrane vesicles at the preparative scale. Recent developments, both in instrumentation and procedures, are described. The major achievements in plant membrane fractionation obtained with free flow electrophoresis are outlined. The related procedures are both analytical and preparative: they separate tonoplast and plasma membrane simultaneously from the same homogenate, they discriminate for one type of membrane vesicles of opposite orientation, and process large quantities of membrane material by reason of the continuous flow mode. Recent advances using electromigration techniques that permit confirmation of the dynamic state of membranes, characterisation of complex membrane-dependent functions and discovery of new membrane-localised activities are presented. 相似文献
2.
Shira Weingarten-Gabbay Susan Klaeger Siranush Sarkizova Leah R. Pearlman Da-Yuan Chen Kathleen M.E. Gallagher Matthew R. Bauer Hannah B. Taylor W. Augustine Dunn Christina Tarr John Sidney Suzanna Rachimi Hasahn L. Conway Katelin Katsis Yuntong Wang Del Leistritz-Edwards Melissa R. Durkin Christopher H. Tomkins-Tinch Pardis C. Sabeti 《Cell》2021,184(15):3962-3980.e17
3.
Klausdieter Bauer 《Human genetics》1970,10(1):1-7
Summary The rôle of several structural and functional factors and of concentration on the cross-reactions of 28 human plasma proteins with their homologues in animal blood was investigated. The Immunological Evolution Group (IEG) system was employed for this purpose as described earlier (Bauer, 1970 a). No interaction of structural factors was detected, while an influence of serum level of the different proteins could not be ruled out with certainty.At least in the case of the 4 immunoglobulins and the 3 complement factors, included in the IEG-system, protein function and evolution show some degree of correlation, indicating the influence of function on molecular evolution in the case of these plasma proteins. 相似文献
4.
5.
The Effect of Visual Representation Style in Problem-Solving: A Perspective from Cognitive Processes
Using results from a controlled experiment and simulations based on cognitive models, we show that visual presentation style can have a significant impact on performance in a complex problem-solving task. We compared subject performances in two isomorphic, but visually different, tasks based on a card game of SET. Although subjects used the same strategy in both tasks, the difference in presentation style resulted in radically different reaction times and significant deviations in scanpath patterns in the two tasks. Results from our study indicate that low-level subconscious visual processes, such as differential acuity in peripheral vision and low-level iconic memory, can have indirect, but significant effects on decision making during a problem-solving task. We have developed two ACT-R models that employ the same basic strategy but deal with different presentations styles. Our ACT-R models confirm that changes in low-level visual processes triggered by changes in presentation style can propagate to higher-level cognitive processes. Such a domino effect can significantly affect reaction times and eye movements, without affecting the overall strategy of problem solving. 相似文献
6.
Frankia is the diverse bacterial genus that fixes nitrogen within root nodules of actinorhizal trees and shrubs. Systematic and ecological
studies of Frankia have been hindered by the lack of morphological, biochemical, or other markers to readily distinguish strains. Recently,
nucleotide sequence of 16 S RNA from the small ribosomal subunit has been used to classify and identify a variety of microorganisms.
We report nucleotide sequences from portions of the 16 S ribosomal RNA from Frankia strains AcnI1 isolated from Alnus viridis ssp. crispa (Ait.) Turrill and PtI1 isolated from Purshia tridentata (Pursh) DC. The number of nucleotide base substitutions and gaps we find more than doubles the previously reported sequence
diversity for the same variable regions within other strains of Frankia. 相似文献
7.
8.
Dr. Karl Bauer 《Plant Systematics and Evolution》1890,40(5):188-191
Ohne Zusammenfassung 相似文献
9.
Dr. Karl Bauer 《Plant Systematics and Evolution》1890,40(6):218-221
Ohne Zusammenfassung 相似文献
10.
Marina Burgos-Silva Patricia Semedo-Kuriki Cassiano Donizetti-Oliveira Priscilla Barbosa Costa Marco Antonio Cenedeze Meire Ioshie Hiyane Alvaro Pacheco-Silva Niels Olsen Saraiva Camara 《PloS one》2015,10(11)
Acute and chronic kidney injuries (AKI and CKI) constitute syndromes responsible for a large part of renal failures, and are today still associated with high mortality rates. Given the lack of more effective therapies, there has been intense focus on the use stem cells for organ protective and regenerative effects. Mesenchymal stem cells (MSCs) have shown great potential in the treatment of various diseases of immune character, although there is still debate on its mechanism of action. Thus, for a greater understanding of the role of MSCs, we evaluated the effect of adipose tissue-derived stem cells (AdSCs) in an experimental model of nephrotoxicity induced by folic acid (FA) in FVB mice. AdSC-treated animals displayed kidney functional improvement 24h after therapy, represented by reduced serum urea after FA. These data correlated with cell cycle regulation and immune response modulation via reduced chemokine expression and reduced neutrophil infiltrate. Long-term analyses, 4 weeks after FA, indicated that AdSC treatment reduced kidney fibrosis and chronic inflammation. These were demonstrated by reduced interstitial collagen deposition and tissue chemokine and cytokine expression. Thus, we concluded that AdSC treatment played a protective role in the framework of nephrotoxic injury via modulation of inflammation and cell cycle regulation, resulting in reduced kidney damage and functional improvement, inhibiting organ fibrosis and providing long-term immune regulation. 相似文献