全文获取类型
收费全文 | 9483篇 |
免费 | 1783篇 |
国内免费 | 1212篇 |
出版年
2024年 | 102篇 |
2023年 | 516篇 |
2022年 | 525篇 |
2021年 | 754篇 |
2020年 | 641篇 |
2019年 | 607篇 |
2018年 | 461篇 |
2017年 | 455篇 |
2016年 | 401篇 |
2015年 | 454篇 |
2014年 | 569篇 |
2013年 | 684篇 |
2012年 | 427篇 |
2011年 | 473篇 |
2010年 | 359篇 |
2009年 | 445篇 |
2008年 | 449篇 |
2007年 | 479篇 |
2006年 | 408篇 |
2005年 | 371篇 |
2004年 | 293篇 |
2003年 | 310篇 |
2002年 | 250篇 |
2001年 | 218篇 |
2000年 | 160篇 |
1999年 | 167篇 |
1998年 | 134篇 |
1997年 | 114篇 |
1996年 | 122篇 |
1995年 | 100篇 |
1994年 | 107篇 |
1993年 | 88篇 |
1992年 | 81篇 |
1991年 | 79篇 |
1990年 | 49篇 |
1989年 | 53篇 |
1988年 | 43篇 |
1987年 | 49篇 |
1986年 | 39篇 |
1985年 | 60篇 |
1984年 | 50篇 |
1983年 | 39篇 |
1982年 | 53篇 |
1981年 | 42篇 |
1980年 | 36篇 |
1979年 | 32篇 |
1978年 | 32篇 |
1977年 | 25篇 |
1976年 | 19篇 |
1975年 | 20篇 |
排序方式: 共有10000条查询结果,搜索用时 929 毫秒
1.
《Cell reports》2020,30(4):1152-1163.e4
- Download : Download high-res image (170KB)
- Download : Download full-size image
2.
T. J. Wojciechowski 《Biometrical journal. Biometrische Zeitschrift》1987,29(8):953-959
In this paper very simple nonparametric classification rule for mixtures of discrete and continuous random variables is described. It is based on the method of nearest neighbor proposed by Cover and Hart (1967). The bounds on the limit of the nearest neighbor rule risks are given. Both lower and upper bound depend on the Bayes risk and the loss function. Finally the method is compared with other existing methods on some practical data set. 相似文献
3.
《Molecular & cellular proteomics : MCP》2020,19(7):1161-1178
- Download : Download high-res image (250KB)
- Download : Download full-size image
- •XL-MS reveals new PPIs in yeast mitochondria under glycerol and glucose condition.
- •Significant but limited results from quantitative XL-MS experiments.
- •Ndi1 participates in a CIII2CIV2 respiratory supercomplex.
- •Min8 promotes assembly of Cox12 into an intermediate complex IV.
4.
《Molecular & cellular proteomics : MCP》2020,19(1):142-154
- Download : Download high-res image (133KB)
- Download : Download full-size image
- •Flow cytometry analysis is used to isolate ASC speck(+) NPC cells.
- •Proteome analysis of ASC speck(+) NPC cells reveals enriched mitochondrial OxPhos proteins.
- •OxPhos proteins mediate NLRP3 inflammasome activation through mtROS.
- •OxPhos proteins, NDUFB8 and ATP5B are correlated with NPC local recurrence.
5.
Yunfan Sun Liang Wu Yu Zhong Kaiqian Zhou Yong Hou Zifei Wang Zefan Zhang Jiarui Xie Chunqing Wang Dandan Chen Yaling Huang Xiaochan Wei Yinghong Shi Zhikun Zhao Yuehua Li Ziwei Guo Qichao Yu Liqin Xu Jia Fan 《Cell》2021,184(2):404-421.e16
- Download : Download high-res image (233KB)
- Download : Download full-size image
6.
7.
《Cell reports》2020,30(5):1504-1514.e7
- Download : Download high-res image (117KB)
- Download : Download full-size image
8.
N-糖蛋白去糖基化酶(PNGase)是一种广泛存在于真菌、植物、哺乳动物中的去糖基化酶,可以水解N-糖蛋白或 N-糖肽上天冬酰胺与寡糖链连接的化学键,并释放出完整的N-寡糖。PNGase在生物体内参与蛋白质降解、器官发育、个体生长等过程。人PNGase基因功能缺陷会导致先天性去糖基化障碍,小鼠PNGase缺陷会导致胚胎致死性,线虫PNGase缺陷使其寿命下降。本文对PNGase在不同物种的分布、蛋白质结构、酶学功能及生物学功能进行阐述,为PNGase的生理病理功能及致病机制的基础研究提供思路,为PNGase作为糖生物学工具酶或药物开发的创新应用研究奠定基础。 相似文献
9.
We studied whether the time-varying forces that control unstable foot–ground interactions provide insight into the neural control of dynamic leg function. Twenty elite (10 F, 26.4 ± 3.5 yrs) and 20 recreational (10 F, 24.8 ± 2.4 yrs) athletes used an isolated leg to maximally compress a slender spring designed to buckle at low forces while seated. The foot forces during the compression at the edge of instability quantify the maximal sensorimotor ability to control dynamic foot–ground interactions. Using the nonlinear analysis technique of attractor reconstruction, we characterized the spatial (interquartile range IQR) and geometric (trajectory length TL, volume V, and sum of edge lengths SE) features of the dynamical behavior of those force time series. ANOVA confirmed the already published effect of sex, and a new effect of athletic ability, respectively, in TL (p = 0.014 and p < 0.001), IQR (p = 0.008 and p < 0.001), V (p = 0.034 and p = 0.002), and SE (p = 0.033 and p < 0.001). Further analysis revealed that, for recreational athletes, females exhibited weaker corrective actions and greater stochasticity than males as per their greater mean values of TL (p = 0.003), IQR (p = 0.018), V (p = 0.017), and SE (p = 0.025). Importantly, sex differences disappeared in elite athletes. These results provide an empirical link between sex, athletic ability, and nonlinear dynamical control. This is a first step in understanding the sensorimotor mechanisms for control of unstable foot–ground interactions. Given that females suffer a greater incidence of non-contact knee ligament injuries, these non-invasive and practical metrics of leg dexterity may be both indicators of athletic ability, and predictors of risk of injury. 相似文献
10.
Birds often lose feathers during predation attempts, and thisability has evolved as a means of escape. Because predatorsare more likely to grab feathers on the rump and the back thanon the ventral side of an escaping bird, we predicted that theformer feathers would have evolved to be relatively looselyattached as an antipredator strategy in species that frequentlydie from predation. We estimated the force required to removefeathers from the rump, back, and breast by pulling featherswith a spring balance from a range of European bird speciesin an attempt to investigate ecological factors associated withease of feather loss during predation attempts. The force requiredto loosen a feather from the rump was less than that requiredto loosen a feather from back, which in turn was less than thatrequired to loosen a feather from the breast. The relative forceneeded to loosen rump feathers compared with feathers from theback and the breast was smaller for prey species preferred bythe most common predator of small passerine birds, the sparrowhawkAccipiter nisus. Likewise, the relative force was also smallerin species with a high frequency of complete tail loss amongfree-living birds, which we used as an index of the frequencyof failed predation attempts. The relative force required toremove feathers from the rump was smaller in species with ahigh frequency of fear screams, another measure of the relativeimportance of predation as a cause of death. Feather loss requiredparticularly little force among solitarily breeding bird speciesthat suffer the highest degree of predation. Antipredator defensein terms of force required to remove feathers from the rumpwas larger in species with a strong antiparasite defense interms of T-cellmediated immune response. These findingsare consistent with the hypothesis that different defenses areantagonistic and that they are traded off against each other. 相似文献