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排序方式: 共有484条查询结果,搜索用时 31 毫秒
1.
[3H]Pteroylglutamic acid (PteGlu) uptake was studied using brush-border membrane vesicles isolated from rat kidney. Results on the uptake of [3H]PteGlu by brush-border membrane vesicles incubated in media of increasing osmolarities demonstrated that uptake was contributed by two components, intravesicular transport and membrane binding. Both the components of the uptake exhibited similar pH dependence, with maxima at pH 5.6, and were found to be saturable mechanisms with Km values of 6.7.10(-7) and 11.2.10(-7) M, respectively. These studies show that PteGlu is transported by isolated rat kidney brush-border membrane vesicles in a manner consistent with a saturable system and that a binding component may be functionally associated with this. 相似文献
2.
Y K Gupta P Bhandari A Chugh S D Seth K S Dixit K P Bhargava 《Indian journal of experimental biology》1989,27(1):52-54
The role of opioid and histaminergic system in morphine induced emesis was investigated in dogs. Morphine (25 micrograms, icv) consistently evoked emesis with an average latency of 195 +/- 29 sec which was fully accounted for by an action on the chemoreceptor trigger zone (CTZ) as its ablation rendered animals refractory to vomiting. Intraventricular pretreatment with opioid antagonist naloxone, histamine H1 antagonist mepyramine and H2 antagonists metiamide and cimetidine afforded protection to icv morphine emesis. The CSF histamine concentration was significantly raised 5 min after icv morphine administration. The results suggest that both endogenous opioid and histamine are involved in morphine emesis. Naloxone in high doses (1600 micrograms, icv) elicited emesis which was not blocked by CTZ ablation confirming our earlier report. 相似文献
3.
Analysis by 1H-NMR spectroscopic techniques of the conformation of the N-terminal segment of the LC1 alkali light chain of rabbit skeletal muscle has shown that this portion of the molecule adopts a well-defined elongated configuration. This rod-like feature is a consequence of the Ala/Pro-rich composition and the functional aspects of such conformational preference in this and similar segments in other proteins are discussed. 相似文献
4.
A spontaneous ameloblastic odontoma was found in an 86-week-old male Fischer 344 rat. Radiographic and histopathologic characteristics confirmed the diagnosis as a true benign neoplasm. 相似文献
5.
Ambikesh Soni Manohar Prasad Bhandari Gagan Kant Tripathi Priyavand Bundela Pradeep Kumar Khiriya Purnima Swarup Khare Manoj Kumar Kashyap Abhijit Dey Balachandar Vellingiri Suresh Sundaramurthy Arisutha Suresh José M. Pérez de la Lastra 《Journal of cellular and molecular medicine》2023,27(6):737-762
In recent years, drug manufacturers and researchers have begun to consider the nanobiotechnology approach to improve the drug delivery system for tumour and cancer diseases. In this article, we review current strategies to improve tumour and cancer drug delivery, which mainly focuses on sustaining biocompatibility, biodistribution, and active targeting. The conventional therapy using cornerstone drugs such as fludarabine, cisplatin etoposide, and paclitaxel has its own challenges especially not being able to discriminate between tumour versus normal cells which eventually led to toxicity and side effects in the patients. In contrast to the conventional approach, nanoparticle-based drug delivery provides target-specific delivery and controlled release of the drug, which provides a better therapeutic window for treatment options by focusing on the eradication of diseased cells via active targeting and sparing normal cells via passive targeting. Additionally, treatment of tumours associated with the brain is hampered by the impermeability of the blood–brain barriers to the drugs, which eventually led to poor survival in the patients. Nanoparticle-based therapy offers superior delivery of drugs to the target by breaching the blood–brain barriers. Herein, we provide an overview of the properties of nanoparticles that are crucial for nanotechnology applications. We address the potential future applications of nanobiotechnology targeting specific or desired areas. In particular, the use of nanomaterials, biostructures, and drug delivery methods for the targeted treatment of tumours and cancer are explored. 相似文献
6.
Nitrate, nitrite and nitrous oxide were denitrified to N2 gas by washed cells ofRhizobium japonicum CC706 as well as by bacteroids prepared from root nodules ofGlycine max (L.) Merr. (CV. Clark 63). Radiolabelled N2 was produced from either K15NO3 or Na15NO2 by washed cells ofRh. japonicum CC705 grown with either nitrate only (5 mM) or nitrate (5 mM) plus glutamate (10 mM). Nitrogen gas was also produced from N2O. Similar results were obtained with bacteroids ofG. max. The stoichiometry for the utilization of15NO
3
-
or15NO
2
-
and the produciton of15N2 was 2:1 and for N2O utilization and N2 production it was 1:1. Some of the15N2 gas produced by denitrification of15NO
3
-
in bacteroids was recycled via nitrogenase into cell nitrogen. 相似文献
7.
The technique of fluorescence quenching by the non-ionic quenchers acrylamide and nicotinamide has been used to probe the accessibility of the environmentally sensitive N-(bromoacetyl)-N'-(1-sulpho-5-naphthyl) ethylenediamine (1,5-Br-AEDANS) fluorophore attached to either Cys-177 of the A1-light chain or the SH1 thiol (Cys-707) of the myosin subfragment (S1) heavy chain. Neither quencher caused any detrimental effects to the ATPase activities of S1 under the conditions of the experiments. It was found that the fluorophore on the isolated light chain was highly exposed to solvent and although this exposure was reduced on hybridization into S1(A1-AEDANS), the probe was still accessible to solvent. This exposure was unaltered by formation of binary complexes with either Mg.ATP or actin or by the formation of a weakly associated acto-S1 complex (in which the Cys-697 and Cys-707 residues of S1 were crosslinked with p-phenylenedimaleimide). The lack of corresponding change in lambda max of emission and quantum yield supported the quenching date and indicated that actin neither binds directly to this region nor induces any significant conformational changes in this locality despite the observation that the A1-Cys-707 moves some 3 nm closer to a point on actin in the weak-binding state (Trayer, H.R. and Trayer, I.P. (1988) Biochemistry, 27, 5718-5727). Parallel experiments with the fluorophore attached to the Cys-707 of the S1 indicated that this region was less accessible to solvent than the light chain thiol despite its ease of labelling. This exposure was not significantly altered by binary complex formation with actin and Mg.ATP, although spectral changes in the absence of quencher support the notion that some conformational change is occurring in this region. 相似文献
8.
A new furanobicoumarin rhamnoside has been characterized from the whole plant extract of Lasiosiphon eriocephalus. 相似文献
9.
Atanu Sarkar 《EcoHealth》2010,7(1):114-126
Millions of people living in India are at risk by consuming arsenic contaminated groundwater. Several technological solutions
have failed to address the problem due to segmental approaches, resulting in human suffering for a period of three decades.
The article is based on an analysis of arsenic-related health problems from an ecosystem perspective through a primary survey
conducted in five arsenic affected villages in the state of West Bengal and review of existing research and policy documents.
Although modern agricultural practices and drinking water policies have resulted in arsenic contamination of groundwater,
current mitigation policy is essentially confined to biomedical approaches, which includes potable water supply and medical
care. The study also shows that existing disparity, difficulty in coping, inaccessibility to health service and potable water
supply and lack of participation in decision making have resulted in more suffering among the poor. On the other hand, spreading
of arsenic contamination in the ecosystem remains unabated. Foods grown in the affected area have emerged as additional sources
of exposure to humans. There is lack of evidence of any perceivable benefits due to sustainable agriculture, as present nature
of agriculture practice is essentially driven by crop yield only. Further research is needed to generate credible evidence
of alternative agriculture paradigms that may eventually reduce body burden of arsenic through reduced dependency on groundwater. 相似文献
10.
Arjun H. Ananth Natarajan Manikandan Ravi Kumar Rajan Ramakrishnan Elancheran Kunasekaran Lakshmithendral Muthiah Ramanathan Atanu Bhattacharjee Senthamaraikannan Kabilan 《化学与生物多样性》2020,17(2)
Breast Cancer (BCa) is the most often diagnosed cancer among women who were in the late 1940’s. Breast cancer growth is largely dependent on the expression of estrogen and progesterone receptor. Breast cancer cells may have one, both, or none of these receptors. The treatment for breast cancer may involve surgery, hormonal therapy (Tamoxifen, an aromatase inhibitor, etc.) and oral chemotherapeutic drugs. The molecular docking technique reported the findings on the potential binding modes of the 2‐(2‐bromo‐3‐nitrophenyl)‐5‐phenyl‐1,3,4‐oxadiazole derivatives with the estrogen receptor (PDB ID: 3ERT). The 1,3,4‐oxadiazole derivatives 4a – 4j have been synthesized and described by spectroscopic method. 2‐(2‐Bromo‐6‐nitrophenyl)‐5‐(4‐bromophenyl)‐1,3,4‐oxadiazole ( 4c ) was reconfirmed by single‐crystal XRD. All the compounds have been tested in combination with generic Imatinib pharmaceutical drug against breast cancer cell lines isolated from Caucasian woman MCF‐7, MDA‐MB‐453 and MCF‐10A non‐cancer cell lines. The compounds with the methoxy (in 4c ) and methyl (in 4j ) substitution were shown to have significant cytotoxicity, with 4c showing dose‐dependent activation and decreased cell viability. The mechanism of action was reported by induced apoptosis and tested by a DNA enzyme inhibitor experiment (ELISA) for Methyl Transferase. Molecular dynamics simulations were made for hit molecule 4c to study the stability and interaction of the protein?ligand complex. The toxicity properties of ADME were calculated for all the compounds. All these results provide essential information for further clinical trials. 相似文献