全文获取类型
收费全文 | 3722篇 |
免费 | 281篇 |
国内免费 | 1篇 |
专业分类
4004篇 |
出版年
2024年 | 4篇 |
2023年 | 25篇 |
2022年 | 65篇 |
2021年 | 116篇 |
2020年 | 64篇 |
2019年 | 85篇 |
2018年 | 88篇 |
2017年 | 79篇 |
2016年 | 154篇 |
2015年 | 214篇 |
2014年 | 220篇 |
2013年 | 309篇 |
2012年 | 312篇 |
2011年 | 311篇 |
2010年 | 187篇 |
2009年 | 149篇 |
2008年 | 245篇 |
2007年 | 231篇 |
2006年 | 240篇 |
2005年 | 178篇 |
2004年 | 171篇 |
2003年 | 134篇 |
2002年 | 112篇 |
2001年 | 34篇 |
2000年 | 26篇 |
1999年 | 21篇 |
1998年 | 27篇 |
1997年 | 22篇 |
1996年 | 14篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 16篇 |
1992年 | 13篇 |
1991年 | 19篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 14篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1970年 | 2篇 |
1910年 | 2篇 |
排序方式: 共有4004条查询结果,搜索用时 0 毫秒
151.
152.
153.
Silvia Barbi Massimo Messori Tiziano Manfredini Martina Pini Monia Montorsi 《Biopolymers》2019,110(5):e23250
In this study proteins extracted from prepupae of Hermetia illucens, also known as black soldier fly, are investigated as promising base for a new type of bioplastics for agricultural purposes. Design of experiments techniques are employed to perform a rational study on the effects of different combination of glycerol as plasticizer, citric acid as cross-linking agent and distilled water as solvent on the capability of proteins to form a free-standing film through casting technique, keeping as fixed the quantity of proteins. Glycerol shows interesting properties as plasticizer contributing to the formation of homogenous and free-standing film. Moreover, mechanical and thermal characterizations are performed to estimate the effect of increasing amounts of proteins on the final properties and thickness of the specimens. Proteins derived from H. illucens can be successfully employed as base for bioplastics to be employed for agricultural purposes. 相似文献
154.
155.
Trumhová Kateřina Holzinger Andreas Obwegeser Sabrina Neuner Gilbert Pichrtová Martina 《Protoplasma》2019,256(6):1681-1694
Protoplasma - Green algae of the genus Zygnema form extensive mats and produce large amounts of biomass in shallow freshwater habitats. Environmental stresses including freezing may perturb these... 相似文献
156.
Kuběnová Barbora Ostner Julia Schülke Oliver Majolo Bonaventura Šmilauer Petr Konečná Martina 《International journal of primatology》2019,40(3):300-315
International Journal of Primatology - In several cercopithecine species males exhibit a specific type of male–infant–male interaction during which two males briefly manipulate an... 相似文献
157.
Romina Sellaro Robert W. Smith Martina Legris Christian Fleck Jorge J. Casal 《Plant, cell & environment》2019,42(2):606-617
Vegetation shade is characterized by marked decreases in the red/far‐red ratio and photosynthetic irradiance. The activity of phytochrome in the field has typically been described by its photoequilibrium, defined by the photochemical properties of the pigment in combination with the spectral distribution of the light. This approach represents an oversimplification because phytochrome B (phyB) activity depends not only on its photochemical reactions but also on its rates of synthesis, degradation, translocation to the nucleus, and thermal reversion. To account for these complex cellular reactions, we used a model to simulate phyB activity under a range of field conditions. The model provided values of phyB activity that in turn predicted hypocotyl growth in the field with reasonable accuracy. On the basis of these observations, we define two scenarios, one is under shade, in cloudy weather, at the extremes of the photoperiod or in the presence of rapid fluctuations of the light environment caused by wind‐induced movements of the foliage, where phyB activity departs from photoequilibrium and becomes affected by irradiance and temperature in addition to the spectral distribution. The other scenario is under full sunlight, where phyB activity responds mainly to the spectral distribution of the light. 相似文献
158.
159.
160.