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71.
Geun-Shik Lee Yuanzheng He Edward J. Dougherty Maria Jimenez-Movilla Matteo Avella Sean Grullon David S. Sharlin Chunhua Guo John A. Blackford Jr. Smita Awasthi Zhenhuan Zhang Stephen P. Armstrong Edra C. London Weiping Chen Jurrien Dean S. Stoney Simons Jr. 《The Journal of biological chemistry》2013,288(21):15167-15180
TTLL5/STAMP (tubulin tyrosine ligase-like family member 5) has multiple activities in cells. TTLL5 is one of 13 TTLLs, has polyglutamylation activity, augments the activity of p160 coactivators (SRC-1 and TIF2) in glucocorticoid receptor-regulated gene induction and repression, and displays steroid-independent growth activity with several cell types. To examine TTLL5/STAMP functions in whole animals, mice were prepared with an internal deletion that eliminated several activities of the Stamp gene. This mutation causes both reduced levels of STAMP mRNA and C-terminal truncation of STAMP protein. Homozygous targeted mutant (Stamptm/tm) mice appear normal except for marked decreases in male fertility associated with defects in progressive sperm motility. Abnormal axonemal structures with loss of tubulin doublets occur in most Stamptm/tm sperm tails in conjunction with substantial reduction in α-tubulin polyglutamylation, which closely correlates with the reduction in mutant STAMP mRNA. The axonemes in other structures appear unaffected. There is no obvious change in the organs for sperm development of WT versus Stamptm/tm males despite the levels of WT STAMP mRNA in testes being 20-fold higher than in any other organ examined. This defect in male fertility is unrelated to other Ttll genes or 24 genes previously identified as important for sperm function. Thus, STAMP appears to participate in a unique, tissue-selective TTLL-mediated pathway for α-tubulin polyglutamylation that is required for sperm maturation and motility and may be relevant for male fertility. 相似文献
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73.
Courtney M. Tate Wayne Blosser Lisa Wyss Glenn Evans Qi Xue Yong Pan Louis Stancato 《The Journal of biological chemistry》2013,288(9):6743-6753
LY2228820 dimesylate is a highly selective small molecule inhibitor of p38α and p38β mitogen-activated protein kinases (MAPKs) that is currently under clinical investigation for human malignancies. p38 MAPK is implicated in a wide range of biological processes, in particular those that support tumorigenesis. One such process, angiogenesis, is required for tumor growth and metastasis, and many new cancer therapies are therefore directed against the tumor vasculature. Using an in vitro co-culture endothelial cord formation assay, a surrogate of angiogenesis, we investigated the role of p38 MAPK in growth factor- and tumor-driven angiogenesis using LY2228820 dimesylate treatment and by shRNA gene knockdown. p38 MAPK was activated in endothelial cells upon growth factor stimulation, with inhibition by LY2228820 dimesylate treatment causing a significant decrease in VEGF-, bFGF-, EGF-, and IL-6-induced endothelial cord formation and an even more dramatic decrease in tumor-driven cord formation. In addition to involvement in downstream cytokine signaling, p38 MAPK was important for VEGF, bFGF, EGF, IL-6, and other proangiogenic cytokine secretion in stromal and tumor cells. LY2228820 dimesylate results were substantiated using p38α MAPK-specific shRNA and shRNA against the downstream p38 MAPK effectors MAPKAPK-2 and HSP27. Using in vivo models of functional neoangiogenesis, LY2228820 dimesylate treatment reduced hemoglobin content in a plug assay and decreased VEGF-A-stimulated vascularization in a mouse ear model. Thus, p38α MAPK is implicated in tumor angiogenesis through direct tumoral effects and through reduction of proangiogenic cytokine secretion via the microenvironment. 相似文献
74.
Scott D. Sampson Eric K. Lund Mark A. Loewen Andrew A. Farke Katherine E. Clayton 《Proceedings. Biological sciences / The Royal Society》2013,280(1766)
The fossil record of centrosaurine ceratopsids is largely restricted to the northern region of western North America (Alberta, Montana and Alaska). Exceptions consist of single taxa from Utah (Diabloceratops) and China (Sinoceratops), plus otherwise fragmentary remains from the southern Western Interior of North America. Here, we describe a remarkable new taxon, Nasutoceratops titusi n. gen. et sp., from the late Campanian Kaiparowits Formation of Utah, represented by multiple specimens, including a nearly complete skull and partial postcranial skeleton. Autapomorphies include an enlarged narial region, pneumatic nasal ornamentation, abbreviated snout and elongate, rostrolaterally directed supraorbital horncores. The subrectangular parietosquamosal frill is relatively unadorned and broadest in the mid-region. A phylogenetic analysis indicates that Nasutoceratops is the sister taxon to Avaceratops, and that a previously unknown subclade of centrosaurines branched off early in the group''s history and persisted for several million years during the late Campanian. As the first well-represented southern centrosaurine comparable in age to the bulk of northern forms, Nasutoceratops provides strong support for the provincialism hypothesis, which posits that Laramidia—the western landmass formed by inundation of the central region of North America by the Western Interior Seaway—hosted at least two coeval dinosaur communities for over a million years of late Campanian time. 相似文献
75.
分生孢子是中国被毛孢(H sinensis)生活史中极为重要的一个环节,其在冬虫夏草侵染和形成过程中有着十分关键的作用.本实验以中国被毛孢纯培养菌种为实验材料,采用显微镜观察了其菌丝体经营养生长产分生孢子过程中显微结构变化,结果表明:中国被毛孢在固体培养条件下,可以形成分生孢子,其形态和产生方式与微循环产孢过程中形成的分生孢子一致,同时,在产孢过程中,还存在瓶梗结构纵裂形成对生分生孢子的现象. 相似文献
76.
山西省重点保护野生植物资源及区系特征研究 总被引:3,自引:0,他引:3
张殷波;张晓龙;卢怡萌;李明 《植物研究》2013,33(1):18-23
以《国家重点保护野生植物名录(第一批)》和《山西省重点保护野生植物名录(第一批)》为依据,建立山西省重点保护野生植物名录。共记录57种保护植物,隶属于38科45属(其中国家Ⅰ级保护2种,国家Ⅱ级保护6种,省级保护49种)。分析结果得出,山西省重点保护野生植物在全省的分布不集中,零散分布于全省61个县区境内,且绝大多数物种的分布范围很狭窄。山西省重点保护野生植物区系具有复杂多样、起源古老、孑遗植物和单种属多等特点,科、属植物区系成分以温带分布型占优势,同时也有较明显的热带性质,过渡性特征比较明显,有其独特的地理优势和保护价值。本研究旨在对山西省重点保护野生植物资源现状及区系特征进行初步研究,从而为野生植物资源的保护和合理有效地利用提供科学的理论依据与参考。 相似文献
77.
78.
《Palaeoworld》2016,25(1):104-115
Roses (Rosa, Rosaceae) are arguably the most admired ornamental plants in the world. Southwestern China is the center of diversity for many extant native species of Rosa and fossils found in this region are critical for understanding the evolution of this genus. Herein, we report a leaf fossil record with good preservation from the late Miocene of Yunnan Province. The opposite and odd-pinnate leaf is composed of seven elliptical leaflets, with close, crenulate, and regular marginal teeth. The stipules are lanceolate and adnate to the petiole. Additionally, the secondary veins are semicraspedodromous, showing the same venation pattern as most living Rosa species in southwestern China. On the basis of the extensive morphological comparisons, we propose a new species, R. fortuita T. Su et Z.K. Zhou n. sp. This is the first confirmed Rosa leaf fossil record in China, and the discovery of R. fortuita n. sp. indicates that Rosa existed in southwestern China by the late Miocene. It suggests that Rosa was distributed in subtropical or temperate forests and shared a similar ecological niche as Rosa in Europe during the Oligocene and Miocene. The modern diversification of Rosa in southwestern China is thought to have been closely associated with the continuous uplift of the Qinghai-Tibet Plateau since the late Miocene, creating complex topography and a variety of climate conditions. 相似文献
79.
Michael J. Benton 《Zoological Journal of the Linnean Society》2016,177(4):813-853
Pareiasaurs were important medium‐ to large‐sized herbivores in the Middle and Late Permian, some 268–252 Ma. They are best known from abundant remains of several taxa found in South Africa and Russia, with isolated finds from other parts of the world. Six genera and species of pareiasaurs have been described from China, and yet they have not been reviewed. Of these six, Tsiyuania may be a synonym of Honania, but this taxon is not further considered here. The other four, which were named for separate finds from the Sunjiagou Formation (Changhsingian, 254–252 Ma), show considerable similarities. Despite earlier suggestions, there are no convincing anatomical characters to distinguish Shihtienfenia, Shansisaurus, and Huanghesaurus, and these three genera are synonymized as Shihtienfenia permica Young & Yeh, 1963. The fourth taxon, Sanchuansaurus pygmaeus Gao, 1989, shows distinctly different teeth from those of Huanghesaurus (= Shihtienfenia), and was about one‐third of the size, so it is retained as a second valid pareiasaur from the Chinese latest Permian. Phylogenetic analysis confirms the validity of these two taxa, with Sanchuansaurus belonging among the derived forms, close to Elginiidae, and with Shihtienfenia associated with Pumiliopareiasauria and Pareiasuchus. 相似文献
80.