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排序方式: 共有9011条查询结果,搜索用时 296 毫秒
961.
Neess D Kiilerich P Sandberg MB Helledie T Nielsen R Mandrup S 《Molecular and cellular biochemistry》2006,289(1-2):149-157
The differential alterations of the spliceosomal UsnRNAs (U1, U2, U4, U5, and U6) were reported to be associated with cellular proliferation and development. The attempt was made in this study to analyze the metabolic pattern of the spliceosomal UsnRNAs during the development of pre-malignant lung lesions induced in experimental mice model system by benzo(a)pyrene (BP) and also to see how tea polyphenols, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), modulate the metabolism of these UsnRNAs during the lung carcinogenesis. No significant changes in the level of the UsnRNAs were seen in the inflammatory lung lesions at 9th week due to treatment of BP. However, there was significant increase in the level of U1 (∼2.5 fold) and U5 (∼47%) in the hyperplastic lung lesions at 17th week. But in the mild dysplastic lung lesions at 26th week, the level of UsnRNAs did not change significantly. Whereas, in the dysplastic lung lesions at 36th week there was significant increase in the level of the U2 (∼2 fold), U4 (∼2.5 fold) and U5 (∼2 fold). Due to the EGCG and ECG treatment the lung lesions at 9th week appeared normal and in the 17th, 26th, and 36th week it appeared as hyperplasia. The level of the UsnRNAs was significantly low in the lung lesions at 9th week (only U2 and U4 by EGCG), at 17th week (only U1 by EGCG/ECG), at 26th week (U1 by ECG; U2, U4 and U5 by EGCG/ECG) and at 36th week (U1 by ECG, U2 and U4 by EGCG/ECG). Whereas, there was significant increase in the level of U5 (by EGCG/ECG) and U6 (by EGCG only) in the lung lesions at 36th and 26th week respectively. This indicates that the metabolism of the spliceosomal UsnRNAs differentially altered during the development of pre-malignant lung lesions by BP as well as during the modulation of the lung lesions by the tea polyphenols. 相似文献
962.
Bagchi D Roy S Patel V He G Khanna S Ojha N Phillips C Ghosh S Bagchi M Sen CK 《Molecular and cellular biochemistry》2006,281(1-2):197-209
Edible berry extracts rich in anthocyanins possess a broad spectrum of therapeutic, pharmacologic and anti-carcinogenic properties.
Six berry extracts (wild blueberry, bilberry, cranberry, elderberry, raspberry seeds and strawberry), singly and in combination,
were studied in our laboratories for antioxidant efficacy, cytotoxic potential, cellular uptake and anti-angiogenic properties.
Combinations of edible berry extracts were evaluated to develop a synergistic formula, OptiBerry, which exhibited high oxygen
radical absorbance capacity (ORAC) value, low cytotoxicity and superior anti-angiogenic properties compared to the other combinations
tested. The current study sought to determine the broad spectrum safety and antioxidant potential of OptiBerry in vivo. Acute oral LD50 of OptiBerry was greater than 5 g/kg in rats. Acute dermal LD50 of OptiBerry was greater than 2 g/kg. No changes in the body weight or adverse effects were observed following necropsy.
Primary skin and eye irritation studies were conducted in New Zealand albino rabbits. OptiBerry was classified as slightly
irritating to the skin (primary skin irritation index 0.3) and minimally irritating to the eye (maximum mean total score 6.0).
The antioxidant potential of OptiBerry was investigated in rats and mice by assessing GSH redox status in tissues as well
as by a unique state-of-the-art electron paramagnetic resonance (EPR) imaging of whole-body redox status. A clinically relevant
hyperbaric oxygen (HBO) exposure system (2 atm, 2 h) was employed to study the antioxidant properties of OptiBerry. OptiBerry
feeding (8 weeks) significantly prevented HBO-induced GSH oxidation in the lung and liver of vitamin E-deficient Sprague Dawley
rats. Furthermore, OptiBerry-fed mice, when exposed to HBO, demonstrated significant protection in whole-body HBO-induced
oxidation compared to the unfed controls by EPR imaging. Taken together, these results indicate that OptiBerry is reasonably
safe and possess antioxidant properties. 相似文献
963.
The folding behavior of cytochrome C (Cyt-C) conjugated with CdS nanorods (CdSnr) is amenable to monitoring by bright field microscopy, the porosity and percolating behavior of such protein conjugated nanoclusters depending on the folding history prior to the conjugation. The method has been used to predict the thermal melting behavior as well as guanidine hydrochloride induced unfolding of Cyt-C. Dynamic light scattering studies indicate that the size distribution of the nanoforms widens in presence of the protein. Furthermore, there is emergence of clusters with higher conductivity and altered zeta potential. Increase of second virial coefficient of CdS nanoforms in the presence of Cyt-C (obtained from static light scattering experiments) implies presence of protein coat over the hydrophobic nanosurface. The results are supported by morphological changes observed through scanning electron microscopy (SEM). Accordingly, the X-ray diffraction pattern shows a change of crystallographic orientations of CdSnr in presence of Cyt-C. 相似文献
964.
Das BB Sen N Roy A Dasgupta SB Ganguly A Mohanta BC Dinda B Majumder HK 《Nucleic acids research》2006,34(4):1121-1132
Emergence of the bi-subunit topoisomerase I in the kinetoplastid family (Trypanosoma and Leishmania) has brought a new twist in topoisomerase research related to evolution, functional conservation and preferential sensitivities to the specific inhibitors of type IB topoisomerase family. In the present study, we describe that naturally occurring flavones baicalein, luteolin and quercetin are potent inhibitors of the recombinant Leishmania donovani topoisomerase I. These compounds bind to the free enzyme and also intercalate into the DNA at a very high concentration (300 µM) without binding to the minor grove. Here, we show that inhibition of topoisomerase I by these flavones is due to stabilization of topoisomerase I–DNA cleavage complexes, which subsequently inhibit the religation step. Their ability to stabilize the covalent topoisomerase I–DNA complex in vitro and in living cells is similar to that of the known topoisomerase I inhibitor camptothecin (CPT). However, in contrast to CPT, baicalein and luteolin failed to inhibit the religation step when the drugs were added to pre-formed enzyme substrate binary complex. This differential mechanism to induce the stabilization of cleavable complex with topoisomerase I and DNA by these selected flavones and CPT led us to investigate the effect of baicalein and luteolin on CPT-resistant mutant enzyme LdTOP1Δ39LS lacking 1–39 amino acids of the large subunit [B. B. Das, N. Sen, S. B. Dasgupta, A. Ganguly and H. K. Majumder (2005) J. Biol. Chem. 280, 16335–16344]. Baicalein and luteolin stabilize duplex oligonucleotide cleavage with LdTOP1Δ39LS. This observation was further supported by the stabilization of in vivo cleavable complex by baicalein and luteolin with highly CPT-resistant L.donovani strain. Taken together, our data suggest that the interacting amino acid residues of topoisomerase I may be partially overlapping or different for flavones and CPT. This study illuminates new properties of the flavones and provide additional insights into the ligand binding properties of L.donovani topoisomerase I. 相似文献
965.
966.
967.
CRTAP is required for prolyl 3- hydroxylation and mutations cause recessive osteogenesis imperfecta 总被引:7,自引:0,他引:7
Morello R Bertin TK Chen Y Hicks J Tonachini L Monticone M Castagnola P Rauch F Glorieux FH Vranka J Bächinger HP Pace JM Schwarze U Byers PH Weis M Fernandes RJ Eyre DR Yao Z Boyce BF Lee B 《Cell》2006,127(2):291-304
Prolyl hydroxylation is a critical posttranslational modification that affects structure, function, and turnover of target proteins. Prolyl 3-hydroxylation occurs at only one position in the triple-helical domain of fibrillar collagen chains, and its biological significance is unknown. CRTAP shares homology with a family of putative prolyl 3-hydroxylases (P3Hs), but it does not contain their common dioxygenase domain. Loss of Crtap in mice causes an osteochondrodysplasia characterized by severe osteoporosis and decreased osteoid production. CRTAP can form a complex with P3H1 and cyclophilin B (CYPB), and Crtap-/- bone and cartilage collagens show decreased prolyl 3-hydroxylation. Moreover, mutant collagen shows evidence of overmodification, and collagen fibrils in mutant skin have increased diameter consistent with altered fibrillogenesis. In humans, CRTAP mutations are associated with the clinical spectrum of recessive osteogenesis imperfecta, including the type II and VII forms. Hence, dysregulation of prolyl 3-hydroxylation is a mechanism for connective tissue disease. 相似文献
968.
969.
Acetylcholinesterase (AChE) has been purified from three different regions of rat brain using Sephadex G 200 column. SDS PAGE (6%) showed single band for the purified AChE fractions. Purified and lyophilized AChE from different (NH4)2SO4 precipitated fractions of three brain parts were utilized for in vitro enzyme kinetics using Dimethoate (Dmt) as inhibitor. K(m) values for cerebellum and hypothalamus were almost similar whereas cerebrum showed a different K(m) value compared to other two regions. With the drug Rivastigmine it was found that % G1 and G4 forms of AChE in three different parts of brain are different. 相似文献
970.