全文获取类型
收费全文 | 12938篇 |
免费 | 1061篇 |
国内免费 | 6篇 |
出版年
2023年 | 92篇 |
2022年 | 175篇 |
2021年 | 311篇 |
2020年 | 230篇 |
2019年 | 307篇 |
2018年 | 345篇 |
2017年 | 314篇 |
2016年 | 460篇 |
2015年 | 644篇 |
2014年 | 647篇 |
2013年 | 866篇 |
2012年 | 940篇 |
2011年 | 972篇 |
2010年 | 623篇 |
2009年 | 531篇 |
2008年 | 690篇 |
2007年 | 683篇 |
2006年 | 583篇 |
2005年 | 545篇 |
2004年 | 493篇 |
2003年 | 457篇 |
2002年 | 431篇 |
2001年 | 236篇 |
2000年 | 192篇 |
1999年 | 215篇 |
1998年 | 119篇 |
1997年 | 111篇 |
1996年 | 104篇 |
1995年 | 86篇 |
1994年 | 79篇 |
1993年 | 63篇 |
1992年 | 101篇 |
1991年 | 116篇 |
1990年 | 105篇 |
1989年 | 97篇 |
1988年 | 113篇 |
1987年 | 82篇 |
1986年 | 76篇 |
1985年 | 74篇 |
1984年 | 71篇 |
1983年 | 59篇 |
1982年 | 42篇 |
1981年 | 47篇 |
1980年 | 46篇 |
1979年 | 56篇 |
1978年 | 31篇 |
1977年 | 42篇 |
1976年 | 33篇 |
1975年 | 36篇 |
1974年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
32.
Adding noise to a visual image makes object recognition more effortful and has a widespread effect on human electrophysiological responses. However, visual cortical processes directly involved in handling the stimulus noise have yet to be identified and dissociated from the modulation of the neural responses due to the deteriorated structural information and increased stimulus uncertainty in the case of noisy images. Here we show that the impairment of face gender categorization performance in the case of noisy images in amblyopic patients correlates with amblyopic deficits measured in the noise-induced modulation of the P1/P2 components of single-trial event-related potentials (ERP). On the other hand, the N170 ERP component is similarly affected by the presence of noise in the two eyes and its modulation does not predict the behavioral deficit. These results have revealed that the efficient processing of noisy images depends on the engagement of additional processing resources both at the early, feature-specific as well as later, object-level stages of visual cortical processing reflected in the P1 and P2 ERP components, respectively. Our findings also suggest that noise-induced modulation of the N170 component might reflect diminished face-selective neuronal responses to face images with deteriorated structural information. 相似文献
33.
34.
Summary The xylanolytic and cellulolytic activity fromCellulomanas were reduced by high O2 concentrations in continous culture as well as by an air flow passed trough the samples, suggesting an inhibition or inactivation of enzymes in such conditions. 相似文献
35.
Eva Decru Nathan Vranken Pedro H. N. Bragança Jos Snoeks Maarten Van Steenberge 《Journal of fish biology》2020,96(5):1186-1201
Based on literature, museum collections and three recent expeditions, an annotated species list of the Lake Edward, East Africa, drainage system is presented, excluding the endemic haplochromines. A total of 34 non-Haplochromis species belonging to 10 families and 21 genera are recorded from the system. Three of these are endemic and two others have been introduced in the region. Six species are new records for the Lake Edward system. A species accumulation curve indicates that we probably covered most of the non-Haplochromis species in the area sampled during the recent expeditions, but undetected species might still be present in the Congolese part of the system, which is poorly sampled. A comparison of the species list with those of neighbouring basins confirmed the placement of the Lake Edward system within the east-coast ichthyofaunal province. 相似文献
36.
37.
38.
The pelagic larval duration ( D PL ) for 10 temperate cryptobenthic species belonging to three families: Gobiidae, Gobiesocidae and Blenniidae was investigated. Overall, the Gobiesocidae presented short D PL s varying between 11 and 18 days, the Gobiidae's D PL ranged between 14 and 39 days, and Parablennius pilicornis (Blenniidae) had an average of 33 days (range 31–37 days). Two subtypes of settlement marks were found among individuals of the same species. 相似文献
39.
Isobyl la Croix 《Curtis's Botanical Magazine》2001,18(3):160-162
40.