全文获取类型
收费全文 | 964篇 |
免费 | 69篇 |
国内免费 | 70篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 37篇 |
2021年 | 61篇 |
2020年 | 46篇 |
2019年 | 48篇 |
2018年 | 43篇 |
2017年 | 32篇 |
2016年 | 61篇 |
2015年 | 52篇 |
2014年 | 76篇 |
2013年 | 85篇 |
2012年 | 89篇 |
2011年 | 76篇 |
2010年 | 55篇 |
2009年 | 56篇 |
2008年 | 60篇 |
2007年 | 37篇 |
2006年 | 37篇 |
2005年 | 19篇 |
2004年 | 23篇 |
2003年 | 18篇 |
2002年 | 3篇 |
2001年 | 14篇 |
2000年 | 6篇 |
1999年 | 15篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 7篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1103条查询结果,搜索用时 324 毫秒
161.
Chun-Jie Huang Yi-Feng Yuan Di Wu Faheem Ahmed Khan Xiao-Fei Jiao Li-Jun Huo 《In vitro cellular & developmental biology. Animal》2017,53(3):258-264
Maintenance and timely termination of cohesion on chromosomes ensures accurate chromosome segregation to guard against aneuploidy in mammalian oocytes and subsequent chromosomally abnormal pregnancies. Sororin, a cohesion stabilizer whose relevance in antagonizing the anti-cohesive property of Wings-apart like protein (Wapl), has been characterized in mitosis; however, the role of Sororin remains unclear during mammalian oocyte meiosis. Here, we show that Sororin is required for DNA damage repair and cohesion maintenance on chromosomes, and consequently, for mouse oocyte meiotic program. Sororin is constantly expressed throughout meiosis and accumulates on chromatins at germinal vesicle (GV) stage/G2 phase. It localizes onto centromeres from germinal vesicle breakdown (GVBD) to metaphase II stage. Inactivation of Sororin compromises the GVBD and first polar body extrusion (PBE). Furthermore, Sororin inactivation induces DNA damage indicated by positive γH2AX foci in GV oocytes and precocious chromatin segregation in MII oocytes. Finally, our data indicate that PlK1 and MPF dissociate Sororin from chromosome arms without affecting its centromeric localization. Our results define Sororin as a determinant during mouse oocyte meiotic maturation by favoring DNA damage repair and chromosome separation, and thereby, maintaining the genome stability and generating haploid gametes. 相似文献
162.
“检测生物组织中糖类、脂肪和蛋白质”是高中生物学必修1《分子和细胞》的一个重要实验。从实验原理、教学组织方式、检测方法以及学习评价等方面对这一实验的教学进行了分析,为高中生物学教学提供参考材料。 相似文献
163.
HBsAg gene was previously introduced into cherry tomato (Lycopersicum esculentum var. cerasiforme) by Agrobacterium-mediated transformation. To investigate the side effect of HBsAg gene in cherry tomato, we analyzed morphological and physiological characteristics of the transgenic mutant N244. The process was performed under field conditions. The results suggested that the mutant N244 exhibited morphological, cytological and physiological variation. First of all, compared with the wild plants NK, N244 had fleshy and dark green leaves, the fewer notches of leaf edge, more adventitious roots and barren seeds. Moreover, the chromosome of N244 were found to be triploid (n = 36) by flow cytometric analysis. Furthermore, N244 has obvious physiological alterations, as compared to NK. It was speculated that transformation of the genes probably led to ploidy variation, and further caused phenotype and physiological changes of plants. Our study will reveal side effects of the mutants, and promote cultivation of transgenic plants in the field. 相似文献
164.
Li-Ya BaiAi-Xin Liang Jian ZhangFei-Fei Yang Li HanLi-Jun Huo Li-Guo Yang 《Theriogenology》2011,75(1):155-163
A novel somatostatin (SS) DNA vaccine (pGM-CSF/SS), delivered orally by attenuated Salmonella typhimurium (CSO22), was used to immunize female mice at 5, 7, and 11 wk of age; the objective was to investigate the humoral immune response and effects of this vaccine on growth, reproduction and lactation. The pGM-CSF/SS induced SS-specific antibodies, which peaked (3.69 ± 0.89; mean ± S.D) 4 wk after the first booster immunization. Compared with a saline-treated control group, body weight gain of a pGM-CSF/SS immunized group increased 30.3% (23.88 vs. 18.32 g, P < 0.05) during the growth period (from 2 wk after primary immunization to 4 wk after the first booster immunization). Immunized mice had higher plasma estradiol concentrations (84.10 ± 2.16 vs. 81.45 ± 2.12 pg/ml, P < 0.05) and a shorter estrous cycle (4.06 ± 0.75 vs. 5.33 ± 0.49 d, P < 0.05), but serum progesterone concentrations were not significantly affected. Since offspring produced by immunized mice gained weight faster (P < 0.05) in the first 2 wk of life (4.27 ± 0.62 and 7.81 ± 1.30 g in Weeks 1 and 2, respectively vs. 3.70 ± 0.23 and 7.14 ± 0.48 g), we inferred that pGM-CSF/SS could have a direct or indirect role in regulating lactation in mice. In conclusion, GM-CSF and CSO22 served as adjuvant and attenuated live vector, respectively, with efficient oral delivery of an SS DNA vaccine which successfully induced a humoral immune response and enhanced rate of weight gain. Furthermore, the DNA vaccine pGM-CSF/SS affected plasma estradiol concentrations and the estrous cycle, and seemed to enhance lactation performance of female mice. 相似文献
165.
Liao L Xu XW Jiang XW Cao Y Yi N Huo YY Wu YH Zhu XF Zhang XQ Wu M 《Applied and environmental microbiology》2011,77(19):7077-7079
A new agarase, AgaA(CN41), cloned from Vibrio sp. strain CN41, consists of 990 amino acids, with only 49% amino acid sequence identity with known β-agarases. AgaA(CN41) belongs to the GH50 (glycoside hydrolase 50) family but yields neoagarotetraose as the end product. AgaA(CN41) was expressed and characterized. 相似文献
166.
Baoshan Ma Congxin Xie Bin Huo Xuefeng Yang Pei Li 《Environmental Biology of Fishes》2011,90(2):159-169
A collection of 514 Schizothorax o’connori was made between August 2008 and August 2009 from Yarlung Tsangpo River to assess the suitability of three bony structures
for age estimation. The annulus characteristics of otolith, vertebra and opercular bone were described. Location of the first
annulus was validated by daily growth increment (DGI) analysis in the otoliths. Annual periodicity was verified by marginal
increment ratio (MIR) analysis in otoliths and edge analysis in vertebrae and opercular bones. Annuli formed, once a year,
between March and May for all three bony structures. Otoliths, vertebrae and opercular bones were examined to determine which
structure produced the most precise and accurate age estimates in S. o’connori. Vertebrae and otoliths matched closely for the first 21 years of life, while opercular bones appeared to underestimate age.
For older fish, the counts diverged and otoliths consistently providing higher age estimates. Sectioned otoliths proved to
be the most precise and accurate structure for age estimation. The oldest observed schizothoracine fish was 50, more than
twice the longevity previously accepted in S. o’connori. 相似文献
167.
Lee HW Qin YX Kim YM Park EY Hwang JS Huo GH Yang CW Kim WY Kim J 《Cell and tissue research》2011,343(2):429-444
Our knowledge of the embryonic development of the lymphatic vessels within the kidney is limited. The aim of this study was
to establish the time of appearance and the distribution of intra-renal lymphatic vessels in the developing mouse kidney by
using the lymphatic marker, LYVE-1. Kidneys from embryonic day 12 (E12) to E18, from neonates at post-natal day 1 (P1) to
P21, and from adults were studied. In the adult mouse kidney, LYVE-1 was expressed mainly in the lymphatic endothelial cells
(LECs) and in a subset of endothelial cells in the glomerular capillaries. However, in the developing mouse kidney, LYVE-1
was also expressed transiently in F4/80+/CD11b– immature macrophages/dendritic cells and in the developing renal vein. LYVE-1+ lymphatic vessels connected with extra-renal lymphatics were detected in the kidney at E13. F4/80+/CD11b–/LYVE-1+ immature macrophages/dendritic cells appeared prior to the appearance of LYVE-1+ renal lymphatic vessels and were closely intermingled or even formed part of the lymphatic vascular wall. Prox1 was expressed
only in the LYVE-1+ LECs from fetus to adult-hood, but not in LYVE-1+ endothelial cells of the developing renal vein and macrophages/dendritic cells. Thus, lymphatic vessels of the kidney might
originate by extension of extra-renal lymphatics through an active branching process possibly associated with F4/80+/CD11b–/LYVE-1+ macrophages/dendritic cells. 相似文献
168.
Rui-Chang Quan Yong Huang Matthew W. Warren Qi-Kun Zhao Guopeng Ren Sheng Huo Yongcheng Long Jianguo Zhu 《International journal of primatology》2011,32(5):1190-1202
Human impacts on the environment at local or regional scales largely depend on intrinsic characteristics of the population,
such as household size, household number, and human population growth. These demographic factors can vary considerably among
ethnic groups sharing similar ecological landscapes, yet the role of traditional cultural practices in shaping local environmental
impacts is not well known for many parts of the world. We here quantify land-cover changes and their relation to the habitat
of the endangered Rhinopithecus bieti in Tibet, in 2 areas populated by different ethnic groups (polyandrous Tibetans and monogamous Naxi) from 1986 to 2006. Results
indicate that habitat of the monkey decreased greatly within our study area over the 20-yr period. Polyandrous and monogamous
ethnic communities differed in household size, household number, population growth, and per capita and per household land
use. The practice of polyandry by ethnic Tibetan appears to have reduced per capita resource consumption by reducing the growth
of overall household number and increasing household size, which can mitigate the negative effects of higher human density
and population growth on the environment. Ethnic Tibetan may also reduce land impacts by adhering to Buddhist customs and
alternative, more sustainable means of livelihood. Accordingly, the protection of traditional cultural resources, such as
polyandry and Buddhist beliefs, could be an effective way to aid biodiversity and environmental conservation efforts in this
key ecosystem. 相似文献
169.
Malignant gliomas, the most common subtype of primary brain tumors, are characterized by high proliferation, great invasion, and neurological destruction and considered to be the deadliest of human cancers. Analgesic-antitumor peptide (AGAP), one of scorpion toxic polypeptides, has been shown to have antitumor activity. Here, we show that recombinant AGAP (rAGAP) not only inhibits the proliferation of gliomas cell SHG-44 and rat glioma cell C6, but also suppresses the migration of SHG-44 cells during wound healing. To explain these phenomena, we find that rAGAP leads to cell cycle of SHG-44 arrested in G1 phase accompanied by suppressing G1 cell cycle regulatory proteins CDK2, CDK6, and p-RB by means of the down-regulated protein expression of p-AKT. Meanwhile, rAGAP significantly decreases the production of NF-κB, BCL-2, p-p38, p-c-Jun, and p-Erk1/2 and further suppresses the activation of VEGF and MMP-9 in SHG-44 cells. These findings suggest rAGAP inhibit proliferation and migration of SHG-44 cells by arresting cell cycle and interfering p-AKT, NF-κB, BCL-2, and MAPK signaling pathways. 相似文献
170.
Age and growth characteristics of Schizopygopsis younghusbandi Regan, 1905 in the Yarlung Tsangpo River in Tibet,China 总被引:1,自引:0,他引:1
Y.‐J. Duan C.‐X. Xie X.‐J. Zhou B.‐S. Ma B. Huo 《Zeitschrift fur angewandte Ichthyologie》2014,30(5):948-954
To better understand the biology of Schizopygopsis younghusbandi Regan, 1905 and its relationship with management considerations, this study describes the relationships between otolith size and fish length and age, verifies annual periodicity of otolith annulus formation, and estimates the S. younghusbandi growth parameters. These age and growth characteristics were studied using 694 specimens collected from August 2008 to August 2009. Otoliths grew asymmetrically throughout the range of standard length (SL) studied, showing a clear pattern of alternating translucent and opaque bands. Marginal increment ration (MIR) analysis of specimens up to 6 years of age indicated that one opaque band and one translucent band were laid down each year. Maximum observed age was 17 years, corresponding to a female of 35.8 cm SL and 589.1 g body weight (BW). The SL‐BW relationship was described as BW = 1.122 × 10?5 SL3.030 for sexes combined. The von Bertalanffy growth function was used to model back‐calculated lengths as Lt = 338.4 (1?e?0.233 (t + 0.403)) for males, and Lt = 433.9 (1?e?0.194 (t + 0.397)) for females. Growth performance of S. younghusbandi was relatively higher than those of other Schizothoracinaes inhabiting the same river. 相似文献