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181.
Identification and properties of two methyltransferases in conversion of phosphatidylethanolamine to phosphatidylcholine. 总被引:12,自引:4,他引:12 下载免费PDF全文
F Hirata O H Viveros E J Diliberto Jr J Axelrod 《Proceedings of the National Academy of Sciences of the United States of America》1978,75(4):1718-1721
Two methyltransferases involved in the methylation of phosphatidylethanolamine to form phosphatidylcholine were demonstrated in a microsomal fraction of bovine adrenal medulla. The first methyltransferase catalyzes the methylation of phosphatidylethanolamine to form phosphatidyl-N-monomethylethanolamine. This enzyme has an optimum pH of 6.5, a low Km for S-adenosyl-L-methionine (1.4 micron), and an absolute requirement for Mg2+. The second methyltransferase catalyzes the two successive methylations of phodphatidyl-N-monomethylethanolamine to phosphatidyl-N,N-dimethylethanolamine and phosphatidylcholine. In contrast to the first methyltransferase, it has an optimum pH of 10 and a high Km for S-adenosyl-L-methionine (0.1 mM) and does not require Mg2+. 相似文献
182.
Bluman EM; Schnier GS; Avalos BR; Strout MP; Sultan H; Jacobson FW; Williams DE; Carson WE; Caligiuri MA 《Blood》1996,88(10):3887-3893
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Abstract Autonomic nervous system abnormalities in airway control may contribute to the symptoms of asthma, and even to the pathogenesis of bronchial hyperresponsiveness (BHR). Partial pulmonary sympathetic denervation by means of bilateral upper dorsal thoracoscopic D2 –D3 sympathicolysis (TS) is an accepted treatment in severe essential hyperhidrosis (EH). The effects of this intervention on BHR are unknown. The objective of this study was to evaluate whether partial pulmonary sympathetic denervation by means of TS has an effect on BHR. Bronchial challenge tests with histamine, enabling the calculation of the provocative dose causing a 20% reduction in FEV1 (PD20 His ) were performed 1 day before, and 6 weeks and 6 months after TS in 35 patients with severe EH. In nine patients (including three patients with a previous history of asthma) with pre-operative BHR (defined as PD20 His < 2 mg), mean PD20 His did not change significantly at 6 weeks, nor at 6 months after TS (0.62 ± 0.33, 0.71 ± 0.42 and 0.93 ± 0.65 mg, respectively) although there was a non-significant trend towards an increase in PD20 His at 6 months. Three of the 26 patients (12%) without pre-operative BHR became hyperresponsive after TS, whereas 1 of the 9 patients with pre-operative BHR lost hyperresponsiveness. No patient developed asthma symptoms after TS. Upper dorsal thoracoscopic D2 –D3 sympathicolysis performed for the treatment of EH has no significant effects on mean PD20 His and individual loss (11%) or development (12%) of BHR occurs only in a minority of patients. 相似文献
185.
Carlos Antonio Negrato Renan M Montenegro Jr Rosiane Mattar Lenita Zajdenverg Rossana PV Francisco Belmiro Gonçalves Pereira Mauro Sancovski Maria Regina Torloni Sergio A Dib Celeste E Viggiano Airton Golbert Elaine CD Moisés Maria Isabel Favaro Iracema MP Calderon Sonia Fusaro Valeria DD Piliakas José Petronio L Dias Marilia B Gomes Lois Jovanovic 《Diabetology & metabolic syndrome》2010,2(1):1-14
There is an urgent need to find consensus on screening, diagnosing and treating all degrees of DYSGLYCEMIA that may occur during pregnancies in Brazil, considering that many cases of DYSGLYCEMIA in pregnant women are currently not diagnosed, leading to maternal and fetal complications. For this reason the Brazilian Diabetes Society (SBD) and the Brazilian Federation of Gynecology and Obstetrics Societies (FEBRASGO), got together to introduce this proposal. We present here a joint consensus regarding the standardization of clinical management for pregnant women with any degree of Dysglycemia, on the basis of current information, to improve medical assistance and to avoid related complications of Dysglycemia in pregnancy to the mother and the fetus. This consensus aims to standardize the diagnosis among general practitioners, endocrinologists and obstetricians allowing the dissemination of information in basic health units, public and private services, that are responsible for screening, diagnosing and treating disglycemic pregnant patients. 相似文献
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Marco EM Granstrem O Moreno E Llorente R Adriani W Laviola G Viveros MP 《European journal of pharmacology》2007,557(1):37-43
There is evidence for the existence of functional interactions between nicotine and cannabinoids and opioid compounds in adult experimental animals. However, there is scarce information about these relationships in young animals. In the present study we evaluated short and long-term effects of a subchronic nicotine treatment [0.4 mg/kg daily i.p. injections from postnatal day (PND) 34 to PND 43], upon hippocampal and striatal cannabinoid-CB(1) and mu-opioid receptors in Wistar rats of both genders. Rats were sacrificed 2 h after the last nicotine injection (short-term effects, PND 43) or one month later (long-term effects, PND 75). Hippocampal and striatal cannabinoid CB(1) and mu-opioid receptors were quantified by Western blotting. The subchronic nicotine treatment induced a region-dependent long-lasting effect in cannabinoid CB(1) receptor: a significant increase in hippocampal cannabinoid CB(1) receptors and a significant decrease in striatal cannabinoid CB(1) receptors, with these effects being similar in males and females. With respect to mu-opioid receptors, subchronic nicotine induced a significant down-regulation in hippocampal and striatal mu-opioid receptors in the long-term, and within the striatum the effects were more marked in adult males than in females. The present results indicate that juvenile nicotine taking may have implications for the endocannabinoid and endogenous opioid function and for the behaviors served by those systems, this includes possible modification of the response of adults to different psychotropic drugs, i.e. cannabis and morphine/heroin when taken later in life. 相似文献
189.
HR Arias H Xing K MacDougall MP Blanton F Soti WR Kem 《British journal of pharmacology》2009,157(2):320-330
Background and purpose
Benzylidene-anabaseines (BAs) are partial agonists of the α7 nicotinic acetylcholine receptor (nAChR) but their mechanism(s) of action are unknown. Our study explores several possibilities, including direct interactions of BAs with the nAChR channel.Experimental approach
Functional and radioligand-binding assays were used to examine the interaction of two BA analogues, 3-(2,4-dimethoxybenzylidene)-anabaseine (DMXBA) and its primary metabolite 3-(4-hydroxy-2-methoxybenzylidene)-anabaseine (4OH-DMXBA) with both agonist and non-competitive antagonist (NCA)-binding sites on muscle-type nAChRs.Key results
Both BAs non-competitively inhibited ACh activation of human fetal muscle nAChRs and sterically inhibited the specific binding of the NCAs [piperidyl-3,4-3H(N)]-(N-(1-(2-thienyl)cyclohexyl)-3,4-piperidine ([3H]TCP) and [3H]dizocilpine to Torpedo nAChRs in the desensitized state. These compounds modulated [3H]tetracaine, [14C]amobarbital and [3H]TCP binding to resting nAChRs by allosteric mechanisms. Both BAs enhanced [3H]TCP binding when the nAChR was initially in the resting but activatable state, suggesting that both compounds desensitized the Torpedo nAChR. Although DMXBA failed to activate human fetal muscle nAChRs, 4OH-DMXBA was found to be a partial agonist. [3H]Nicotine competition-binding experiments confirmed that 4OH-DMXBA has higher affinity than DMXBA for the agonist sites, and that DMXBA is also a competitive antagonist.Conclusions and implications
3-(4-hydroxy-2-methoxybenzylidene)-anabaseine is a partial agonist for human fetal muscle nAChRs, whereas DMXBA only has competitive and NCA activities. The NCA-binding site for BAs overlaps both the phencyclidine-and dizocilpine-binding sites in the desensitized Torpedo nAChR ion channel. The desensitizing property of BAs suggests another possible mode of non-competitive inhibition in addition to direct channel-blocking mechanisms. 相似文献190.
Emilio Fernandez-Espejo Maria-Paz Viveros Luis Núñez Bart A. Ellenbroek Fernando Rodriguez de Fonseca 《Psychopharmacology》2009,206(4):531-549