全文获取类型
收费全文 | 966篇 |
免费 | 55篇 |
国内免费 | 3篇 |
出版年
2023年 | 10篇 |
2022年 | 30篇 |
2021年 | 32篇 |
2020年 | 23篇 |
2019年 | 49篇 |
2018年 | 55篇 |
2017年 | 30篇 |
2016年 | 41篇 |
2015年 | 40篇 |
2014年 | 70篇 |
2013年 | 84篇 |
2012年 | 81篇 |
2011年 | 83篇 |
2010年 | 38篇 |
2009年 | 33篇 |
2008年 | 37篇 |
2007年 | 32篇 |
2006年 | 27篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 22篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 15篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1993年 | 2篇 |
1992年 | 7篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 3篇 |
1968年 | 2篇 |
排序方式: 共有1024条查询结果,搜索用时 15 毫秒
141.
Abdel-Hamid A. Hamdy Elsayed A. Aboutabl Somayah Sameer Ahmed A. Hussein Ana R. Díaz-Marrero Jos Darias Mercedes Cueto 《Steroids》2009,74(12):927-930
Bioassay-guided purification of an ethanolic extract of Cystoseira myrica against HEPG-2 (liver) and HCT116 (colon) human cancer cell lines led to the isolation of 3-keto-22-epi-28-nor-cathasterone, 1 and cholest-4-ene-3,6-dione, 2. This finding allowed us to report for the first time that a brassinosteroid-related metabolite occurs in seaweed. These compounds showed activity in the range of 12.38–1.16 μM with selective activity of compound 2 to liver cancer cell lines. 相似文献
142.
M.S. Al-Khalifa H.S. Hussein F.M. Diab G.M. Khalil 《Saudi Journal of Biological Sciences》2009,16(2):63-67
Blood samples from camels, sheep, goats and cattle from six Regions in Saudi Arabia were examined for blood parasites. Asir Region camels were disinfected while those of the Eastern, Jazan, Northern Frontiers, Riyadh and Tabouk Regions were infected with Trypanosoma evansi (5–40%), those of Riyadh and the Eastern Regions were infected with Dipetalonema evansi (1–6%) and those of the Eastern, Jazan and Riyadh Regions were infected with Eperythrozoon species (8–20%). Sheep and goats of all tested regions were infected with Theilaria hirci (4–20% and 6–14%, respectively), Theilaria ovis (5–19% and 6–24%, respectively) and Eperthrozoon ovis (2–9% and 2–8%, respectively). Sheep of the Eastern and Northern Frontiers Regions were also infected with Anaplasma ovis (2%) and also those of the Eastern Region were infected with Babesia motasi (4%) as well. Cattle of Asir and Eastern Regions were infected with Anaplasma marginale (1–3.4%) and those of the Eastern, Jazan and Riyadh Regions were infected with Theileria annulata (11.3–25%) and Eperthrozoon wenyoni (1–4%). Moreover, Jazan cattle were infected with Babesia bigemina (6%) and a benign Theileria species (27%). Some of these parasites are recorded in new localities indicating that they are spreading in the country. Also, this is the first report in Saudi Arabia of D. evansi in camels, A. ovis and B. motasi in sheep and A. marginale and B. bigemina in cattle. These parasites may be introduced into the country with infected livestock infested with the vectors of these parasites. The suspected vectors of the detected parasites in Saudi Arabia is discussed. Follow up surveys of blood parasites are recommended to assess their distribution and infection rates in the livestock of all Regions of Saudi Arabia, to make plans for control measures against their vectors. 相似文献
143.
Dilutable nanoemulsions are potent drug delivery vehicles for ophthalmic use due to their numerous advantages as sustained
effect and high ability of drug penetration into the deeper layers of the ocular structure and the aqueous humor. The aim
of this article was to formulate the antiglaucoma drug dorzolamide hydrochloride as ocular nanoemulsion of high therapeutic
efficacy and prolonged effect. Thirty-six systems consisting of different oils, surfactants, and cosurfactants were prepared
and their pseudoternary-phase diagrams were constructed by water titration method. Seventeen dorzolamide hydrochloride nanoemulsions
were prepared and evaluated for their physicochemical and drug release properties. These nanoemulsions showed acceptable physicochemical
properties and exhibited slow drug release. Draize rabbit eye irritation test and histological examination were carried out
for those preparations exhibiting superior properties and revealed that they were nonirritant. Biological evaluation of dorzolamide
hydrochloride nanoemulsions on normotensive albino rabbits indicated that these products had higher therapeutic efficacy,
faster onset of action, and prolonged effect relative to either drug solution or the market product. Formulation of dorzolamide
hydrochloride in a nanoemulsion form offers, thus, a more intensive treatment of glaucoma, a decrease in the number of applications
per day, and a better patient compliance compared to conventional eye drops. 相似文献
144.
145.
Walker JR Alshafie G Nieves N Ahrens J Clagett-Dame M Abou-Issa H Curley RW 《Bioorganic & medicinal chemistry》2006,14(9):3038-3048
All-trans retinoic acid analogues such as N-(4-hydroxyphenyl)retinamide (4-HPR) are effective chemopreventive and chemotherapeutic agents but their utility has been hampered by dose-limiting side effects. The glucuronide derivatives of 4-HPR, the oxygen-linked 4-HPROG and the carbon-linked 4-HPRCG, have been found to be more effective agents. The synthetic route to the fully C-linked analogue of 4-HPROG (4-HBRCG), which employs Suzuki coupling and Umpolung chemistries as key methodologies, is shown. The results of this study show 4-HBRCG to be an effective chemotherapeutic agent in a rat mammary tumor model while being devoid of classical retinoid toxicities. 相似文献
146.
Wael A. El-Sayed Walaa I. El-Sofany Hoda A. R. Hussein Nahed M. Fathy 《Nucleosides, nucleotides & nucleic acids》2017,36(7):474-495
New [(Indolyl)pyrazolyl]-1,3,4-oxadiazole compounds and their derived thioglycosides as well as the corresponding sugar hydrazones were synthesized. The acyclo C-nucleoside analogs of the oxadiazoline base system were also prepared by reaction of acid hydrazides with aldehydo sugars followed by one pot process encompassing acetylation and cyclization of the synthesized hydrazones. The anticancer activity of the newly synthesized compounds was studied against colorectal carcinoma (HCT116), breast adenocarcinoma (MCF7) and prostate cancer (PC3) human tumor cell lines and a number of compounds showed moderate to high activities. 相似文献
147.
Joseph S. Baxter Nichola Johnson Katarzyna Tomczyk Andrea Gillespie Sarah Maguire Rachel Brough Laura Fachal Kyriaki Michailidou Manjeet K. Bolla Qin Wang Joe Dennis Thomas U. Ahearn Irene L. Andrulis Hoda Anton-Culver Natalia N. Antonenkova Volker Arndt Kristan J. Aronson Annelie Augustinsson Olivia Fletcher 《American journal of human genetics》2021,108(7):1190-1203
148.
Hamdan FF Gauthier J Araki Y Lin DT Yoshizawa Y Higashi K Park AR Spiegelman D Dobrzeniecka S Piton A Tomitori H Daoud H Massicotte C Henrion E Diallo O;SD Group Shekarabi M Marineau C Shevell M Maranda B Mitchell G Nadeau A D'Anjou G Vanasse M Srour M Lafrenière RG Drapeau P Lacaille JC Kim E Lee JR Igarashi K Huganir RL Rouleau GA Michaud JL 《American journal of human genetics》2011,(3):1427-316
Little is known about the genetics of nonsyndromic intellectual disability (NSID). We hypothesized that de novo mutations (DNMs) in synaptic genes explain an important fraction of sporadic NSID cases. In order to investigate this possibility, we sequenced 197 genes encoding glutamate receptors and a large subset of their known interacting proteins in 95 sporadic cases of NSID. We found 11 DNMs, including ten potentially deleterious mutations (three nonsense, two splicing, one frameshift, four missense) and one neutral mutation (silent) in eight different genes. Calculation of point-substitution DNM rates per functional and neutral site showed significant excess of functional DNMs compared to neutral ones. De novo truncating and/or splicing mutations in SYNGAP1, STXBP1, and SHANK3 were found in six patients and are likely to be pathogenic. De novo missense mutations were found in KIF1A, GRIN1, CACNG2, and EPB41L1. Functional studies showed that all these missense mutations affect protein function in cell culture systems, suggesting that they may be pathogenic. Sequencing these four genes in 50 additional sporadic cases of NSID identified a second DNM in GRIN1 (c.1679_1681dup/p.Ser560dup). This mutation also affects protein function, consistent with structural predictions. None of these mutations or any other DNMs were identified in these genes in 285 healthy controls. This study highlights the importance of the glutamate receptor complexes in NSID and further supports the role of DNMs in this disorder. 相似文献
149.
150.
Identification of QTL for increased fibrous roots in soybean 总被引:2,自引:0,他引:2
Abdel-Haleem H Lee GJ Boerma RH 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,122(5):935-946
Drought stress adversely affects soybean at various developmental stages, which collectively results in yield reduction. Unpredictable
rainfall has been reported to contribute about 36% to variation of yield difference between the rain-fed and irrigated fields.
Among the drought resistance mechanisms, drought avoidance in genotypes with fibrous roots was recognized to be associated
with drought resistance in soybean. Plant introduction PI416937 was shown to possess fibrous roots and has been used as a
parent in breeding programs to improve soybean productivity. Little information is available on relative contribution and
chromosomal location of quantitative trait loci (QTL) conditioning fibrous roots in soybean. To identify the genomic locations
and genetic bases of this trait, a recombinant inbred line population was derived from a cross between PI416937 and ‘Benning’.
To detect associated QTLs, phenotypic data were collected and analyzed for 2 years under rain-fed field conditions. The selective
genotyping approach was used to reduce the costs and work associated with conducting the QTL analysis. A total of five QTLs
were identified on chromosomes Gm01 (Satt383), Gm03 (Satt339), Gm04 (Sct_191), Gm08 (Satt429), and Gm20 (Sat_299), and together
explained 51% of the variation in root score. Detected QTLs were co-localized with QTLs related to root morphology, suggesting
that fibrous roots QTL may be associated with other morpho-physiological traits and seed yield in soybean. Genetic dissection
of the fibrous roots trait at the individual marker loci will allow for marker-assisted selection to develop soybean genotypes
with enhanced levels of fibrous roots. 相似文献