全文获取类型
收费全文 | 8450篇 |
免费 | 1182篇 |
出版年
2023年 | 41篇 |
2022年 | 97篇 |
2021年 | 189篇 |
2020年 | 114篇 |
2019年 | 155篇 |
2018年 | 171篇 |
2017年 | 131篇 |
2016年 | 243篇 |
2015年 | 405篇 |
2014年 | 473篇 |
2013年 | 502篇 |
2012年 | 718篇 |
2011年 | 689篇 |
2010年 | 472篇 |
2009年 | 381篇 |
2008年 | 495篇 |
2007年 | 547篇 |
2006年 | 543篇 |
2005年 | 563篇 |
2004年 | 498篇 |
2003年 | 412篇 |
2002年 | 439篇 |
2001年 | 74篇 |
2000年 | 51篇 |
1999年 | 86篇 |
1998年 | 95篇 |
1997年 | 59篇 |
1996年 | 57篇 |
1995年 | 47篇 |
1994年 | 55篇 |
1993年 | 51篇 |
1992年 | 65篇 |
1991年 | 36篇 |
1990年 | 34篇 |
1989年 | 44篇 |
1988年 | 47篇 |
1987年 | 43篇 |
1986年 | 33篇 |
1985年 | 31篇 |
1984年 | 30篇 |
1983年 | 26篇 |
1982年 | 29篇 |
1981年 | 28篇 |
1980年 | 28篇 |
1979年 | 29篇 |
1978年 | 25篇 |
1977年 | 19篇 |
1976年 | 19篇 |
1974年 | 20篇 |
1968年 | 16篇 |
排序方式: 共有9632条查询结果,搜索用时 718 毫秒
91.
92.
Niraj Shrestha Pallavi Chaturvedi Xiaoyun Zhu Michael J. Dee Varghese George Christopher Janney Jack O. Egan Bai Liu Mark Foster Lynne Marsala Pamela Wong Celia C. Cubitt Jennifer A. Foltz Jennifer Tran Timothy Schappe Karin Hsiao Gilles M. Leclerc Lijing You Christian Echeverri Catherine Spanoudis Ana Carvalho Leah Kanakaraj Crystal Gilkes Nicole Encalada Lin Kong Meng Wang Byron Fang Zheng Wang Jin-an Jiao Gabriela J. Muniz Emily K. Jeng Nicole Valdivieso Liying Li Richard Deth Melissa M. Berrien-Elliott Todd A. Fehniger Peter R. Rhode Hing C. Wong 《Aging cell》2023,22(5):e13806
93.
94.
Wenping Li Melissa R. Pergande Christopher A. Crutchfield Brian C. Searle Peter S. Backlund Jaqueline A. Picache Kathryn Burkert Nicole M. Yanjanin-Farhat Paul S. Blank Cynthia L. Toth Christopher A. Wassif Forbes D. Porter Stephanie M. Cologna 《Proteomics》2023,23(11):2200378
Niemann-Pick, type C1 (NPC1) is a fatal, neurodegenerative disease, which belongs to the family of lysosomal diseases. In NPC1, endo/lysosomal accumulation of unesterified cholesterol and sphingolipids arise from improper intracellular trafficking resulting in multi-organ dysfunction. With the proximity between the brain and cerebrospinal fluid (CSF), performing differential proteomics provides a means to shed light to changes occurring in the brain. In this study, CSF samples obtained from NPC1 individuals and unaffected controls were used for protein biomarker identification. A subset of these individuals with NPC1 are being treated with miglustat, a glycosphingolipid synthesis inhibitor. Of the 300 identified proteins, 71 proteins were altered in individuals with NPC1 compared to controls including cathepsin D, and members of the complement family. Included are a report of 10 potential markers for monitoring therapeutic treatment. We observed that pro-neuropeptide Y (NPY) was significantly increased in NPC1 individuals relative to healthy controls; however, individuals treated with miglustat displayed levels comparable to healthy controls. In further investigation, NPY levels in a NPC1 mouse model corroborated our findings. We posit that NPY could be a potential therapeutic target for NPC1 due to its multiple roles in the central nervous system such as attenuating neuroinflammation and reducing excitotoxicity. 相似文献
95.
Baumgartner, N. and Fondeville, J. C. 1989. Photocontrol of the hypocotyl hook opening of Sinapis alba seedlings. Involvement of phytochrome and a high irradiance response.
A statistical evaluation of the hypocotyl hook opening (hook opening index) was used for measurement of the hook angle in lots of etiolated Sinapis alba L. cv. Albatros seedlings. Studies of the kinetics for hook opening were carried out in continuous fluorescent white, blue and red light (6, 15 and 40 μmol m-2 s-1 ) with 2-day-old dark-grown seedlings. At the beginning of the irradiation period the photoresponse in red light was the opposite to that in blue (low photon fluences). Blue rapidly induced the hook opening (in less than 20 min), while red produced hook tightening (photon fluences up to 70 mmol m-2 ), which precedes the normal progressive hook opening. For low fluences, the data were consistent with the involvement of phytochrome and a specific blue light photoreceptor. A phytochrome effect was observed in the hook opening, dependent upon a high irradiance response (HIR). This HIR (like that for the inhibition of the hypocotyl elongation) was characterized by a wavelength response curve with maxima in the blue and far-red regions of the spectrum. 相似文献
A statistical evaluation of the hypocotyl hook opening (hook opening index) was used for measurement of the hook angle in lots of etiolated Sinapis alba L. cv. Albatros seedlings. Studies of the kinetics for hook opening were carried out in continuous fluorescent white, blue and red light (6, 15 and 40 μmol m
96.
97.
Regis Vanderesse Laurent Thevenet Michel Marraud Nicole Boggetto Michele Reboud Catherine Corbier 《Journal of peptide science》2003,9(5):282-299
The aminoxy acids NH2-O-C(alpha)HR-CO2H are much more easily obtained in the enantiomerically pure form than the analogous hydrazino acids NH2-NH-C(alpha)HR-CO2H, and it has been shown that the isosteric amidoxy psi[CO-NH-O] and hydrazide psi[CO-NH-NH] amide surrogates Induce two quite similar gamma-like folded structures. An aminoxy acid can also be N-coupled to a peptide aldehyde to give the aldoxime psi[CH = N-O] link or to a peptide ketone to form the ketoxime psi[CR= N-O] link. The former can be further reduced into the hydroxylamine psi[CH2-NH-O] link which gives rise to reduced amidoxy peptides. The structural properties Induced by these amide surrogates were studied, using IR and NMR spectroscopy, paying particular attention to the Z/E-isomerism of the oxime link. In order to investigate their inhibitory potency, the three amide surrogates were introduced in the Pro3-Val4 and Val4-Ala5 position of Z-Ala1-Ala2-Pro3-Val4-Ala5-Ala6-NHiPr, a substrate which is cleaved in the Val4-Ala5 position by human leukocyte elastase (HLE). The [Val4psi[CO-NH-O]Ala5] analogue was still a substrate, while the [Pro3psi[CO-NH-O]Val4] and [Val4psi[CH = N-O]Ala5] pseudopeptides acted as HLE competitive inhibitors. 相似文献
98.
Jonathan P. Balcombe M. Brock Fenton 《Ethology : formerly Zeitschrift fur Tierpsychologie》1988,79(2):158-166
We used playback presentations to free-flying bats of 3 species to assess the influence of echolocation call design and foraging strategy on the role of echolocation calls in communication. Near feeding sites over water, Myotis lucifugus and M. yumanensis responded positively only to echolocation calls of conspecifics. Near roosts, these bats did not respond before young of the year became volant, and after this responded to presentations of echolocation calls of similar and dissimilar design. At feeding sites Lasiurus borealis responded only to echolocation calls of conspecifics and particularly to “feeding buzzes”. While Myotis, particularly subadults, appear to use the echolocation calls of conspecifics to locate feeding sites, L. borealis appears to use the calls of a foraging neighbour attacking prey to identify opportunities for ‘stealing’ food. 相似文献
99.
An autosomal recessive deafness mutant was discovered in our colony of Zucker (ZUC) rats. These mutants behave like shaker-waltzer
deafness mutants, and their inner ear pathology classifies them among neuroepithelial degeneration type of deafness mutants.
To determine whether this rat deafness mutation (−) defines a unique locus or one that has been previously described, we mapped
its chromosomal location. F2 progeny of (Pbrc:ZUC × BN/Crl) A/a B/b
H/h+/− F1 rats were scored for coat color and behavioral phenotypes. Segregation analysis indicated that the deafness locus might be
loosely linked with B on rat Chromosome (Chr) 5 (RNO5). Therefore, 40 −/− rats were scored for BN and ZUC alleles at four additional loci, D5Mit11, D5Mit13, Oprd1, and Gnb1, known to map to RNO5 or its homolog, mouse Chr 4 (MMU4). Linkage analysis established the gene order (cM distance) as D5Mit11–(19.3)–B–(17.9)–D5Mit13–(19.2)–Oprd1–(21.5) − (1.2) Gnb1, placing the deafness locus on distal RNO5. The position of the deafness locus on RNO5 is similar to that ofjerker (je) on MMU4; the phenotypes and patterns of inheritance of the deafness mutation and je are also similar. It seems likely that the mutation affects the rat homolog of je. The rat deafness locus should, therefore, be named jerker and assigned the gene symbol Je.
Received: 13 June 1995 / Accepted: 4 January 1996 相似文献
100.
The family Draconematidae is reviewed. Diagnoses of all taxa are updated or emended, basedupon an evaluation of diagnostic features. Aphylogenetic analysis at the genus level based onparsimony suggested that Tenuidraconema belongsto the Draconematinae. A new genus Bathychaetosoma is erected to accomodate B.uchidai (Kito, 1983). It is characterized by acephalic region with a smooth, non-thickened cuticleand numerous cephalic adhesion tubes located posteriorto the head region and extending over more than twohead diameters along the cervical region. 相似文献