全文获取类型
收费全文 | 15171篇 |
免费 | 1335篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 181篇 |
儿科学 | 535篇 |
妇产科学 | 302篇 |
基础医学 | 2327篇 |
口腔科学 | 361篇 |
临床医学 | 1596篇 |
内科学 | 3272篇 |
皮肤病学 | 274篇 |
神经病学 | 1117篇 |
特种医学 | 537篇 |
外国民族医学 | 1篇 |
外科学 | 2154篇 |
综合类 | 143篇 |
现状与发展 | 20篇 |
一般理论 | 8篇 |
预防医学 | 1192篇 |
眼科学 | 349篇 |
药学 | 1168篇 |
中国医学 | 16篇 |
肿瘤学 | 1000篇 |
出版年
2023年 | 119篇 |
2022年 | 116篇 |
2021年 | 240篇 |
2020年 | 216篇 |
2019年 | 254篇 |
2018年 | 319篇 |
2017年 | 308篇 |
2016年 | 338篇 |
2015年 | 316篇 |
2014年 | 436篇 |
2013年 | 586篇 |
2012年 | 714篇 |
2011年 | 683篇 |
2010年 | 434篇 |
2009年 | 429篇 |
2008年 | 593篇 |
2007年 | 624篇 |
2006年 | 573篇 |
2005年 | 544篇 |
2004年 | 614篇 |
2003年 | 506篇 |
2002年 | 493篇 |
2001年 | 437篇 |
2000年 | 471篇 |
1999年 | 423篇 |
1998年 | 209篇 |
1997年 | 172篇 |
1996年 | 201篇 |
1995年 | 170篇 |
1994年 | 155篇 |
1993年 | 155篇 |
1992年 | 311篇 |
1991年 | 342篇 |
1990年 | 339篇 |
1989年 | 351篇 |
1988年 | 276篇 |
1987年 | 289篇 |
1986年 | 247篇 |
1985年 | 300篇 |
1984年 | 195篇 |
1983年 | 169篇 |
1982年 | 134篇 |
1981年 | 105篇 |
1980年 | 94篇 |
1979年 | 166篇 |
1978年 | 134篇 |
1977年 | 114篇 |
1975年 | 102篇 |
1974年 | 117篇 |
1973年 | 105篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Background Information about medicines safety in children is very limited. Consumer adverse drug reaction (ADR) reports can provide information about serious and unknown ADRs from medicine use in children. Objective To characterize ADRs in children reported by consumers in Europe from 2007 to 2011. Methods We analysed ADRs reported to the European ADR database, EudraVigilance (EV) for individuals from birth to 17 years. Data were characterized with respect to age and sex of the child, type of ADR (system organ class and preferred term), seriousness and suspected medicines (anatomical therapeutic chemical classification system level 1 and 5). Results In total, 240 ADR reports corresponding to 670 ADRs were identified. The relatively largest share of ADRs were reported for infants below 1 year followed by teenagers, and 60 % of all ADRs were reported for girls. The majority of ADRs reported were of the general type (20 %) and nervous system disorders (15 %). The largest share of serious ADRs was of the type nervous system disorders (17 % of all serious). Three cases of death were reported. Vaccines and anti-infectives for systemic use contributed to 30 % of ADRs, antineoplastic and immunomodulating agents for 23 % and sex hormones for 13 %. Conclusion Only few paediatric ADR consumer reports were found in EudraVigilance. Many of these ADRs were serious, and fatal cases were reported, however also nonserious reports were present. The findings indicate that consumer reports may be of value in paediatric ADR signal detection. 相似文献
992.
Andreas Skyschally Barbara Walter Rie Schultz Hansen Gerd Heusch 《Naunyn-Schmiedeberg's archives of pharmacology》2013,386(5):383-391
Connexin 43 is located in the cardiomyocyte sarcolemma and in the mitochondrial membrane. Sarcolemmal connexin 43 contributes to the spread of myocardial ischemia/reperfusion injury, whereas mitochondrial connexin 43 contributes to cardioprotection. We have now investigated the antiarrhythmic dipeptide ZP1609 (danegaptide), which is an analog of the connexin 43 targeting antiarrhythmic peptide rotigaptide (ZP123), in an established and clinically relevant experimental model of ischemia/reperfusion in pigs. Pigs were subjected to 60 min coronary occlusion and 3 h reperfusion. ZP1609 (n?=?10) was given 10 min prior to reperfusion (75 μg/kg b.w. bolus i.v. + 57 μg/kg/min i.v. infusion for 3 h). Immediate full reperfusion (IFR, n?=?9) served as control. Ischemic postconditioning (PoCo, n?=?9; 1 min LAD reocclusion after 1 min reperfusion; four repetitions) was used as a positive control of cardioprotection. Infarct size (TTC) was determined as the end point of cardioprotection. Systemic hemodynamics and regional myocardial blood flow during ischemia were not different between groups. PoCo and ZP1609 reduced infarct size vs. IFR (IFR, 46?±?4 % of area at risk; mean?±?SEM; PoCo, 31?±?4 %; ZP1609, 25?±?5 %; both p?<?0.05 vs. IFR; ANOVA). There were only few arrhythmias during reperfusion such that no antiarrhythmic action of ZP1609 was observed. ZP1609 when given before reperfusion reduces infarct size to a similar extent as ischemic postconditioning. Further studies are necessary to define the mechanism/action of ZP1609 on connexin 43 in cardiomyocytes. 相似文献
993.
Karen Smith Korsholm Jon Hansen Kasper Karlsen Jonathan Filskov Marianne Mikkelsen Thomas Lindenstrøm Signe Tandrup Schmidt Peter Andersen Dennis Christensen 《Vaccine》2014
Vaccines inducing cytotoxic T-cell responses are required to achieve protection against cancers and intracellular infections such as HIV and Hepatitis C virus. Induction of CD8+ T cell responses in animal models can be achieved by the use of viral vectors or DNA vaccines but so far without much clinical success. Here we describe the novel CD8+ T-cell inducing adjuvant, cationic adjuvant formulation (CAF) 09, consisting of dimethyldioctadecylammonium (DDA)-liposomes stabilized with monomycoloyl glycerol (MMG)-1 and combined with the TLR3 ligand, Poly(I:C). Different antigens from tuberculosis (TB10.3, H56), HIV (Gag p24), HPV (E7) and the model antigen ovalbumin were formulated with CAF09 and administering these vaccines to mice resulted in a high frequency of antigen-specific CD8+ T cells. CAF09 was superior in its ability to induce antigen-specific CD8+ T cells as compared to other previously described CTL-inducing adjuvants, CAF05 (DDA/trehalose dibehenate (TDB)/Poly(I:C)), Aluminium/monophosphoryl lipid-A (MPL) and Montanide/CpG/IL-2. The optimal effect was obtained when the CAF09-adjuvanted vaccine was administered by the i.p. route, whereas s.c. administration primed limited CD8+ T-cell responses. The CD4+ T cells induced by CAF09 were mainly of an effector-memory-like phenotype and the CD8+ T cells were highly cytotoxic. Finally, in a mouse therapeutic skin tumor model, the HPV-16 E7 antigen formulated in CAF09 significantly reduced the growth of already established subcutaneous E7-expressing TC-1 tumors in 38% of the mice and in a corresponding prophylactic model 100% of the mice were protected. Thus, CAF09 is a potent new adjuvant which is able to induce CD8+ T-cell responses against several antigens and to enhance the protective efficacy of an E7 vaccine both in a therapeutic and in a prophylactic tumor model. 相似文献
994.
Kristine Blix Sigrid K. Brækkan Saskia le Cessie Finn E. Skjeldestad Suzanne C. Cannegieter John-Bjarne Hansen 《European journal of epidemiology》2014,29(4):277-284
Whether the high incidence of venous thromboembolism (VTE) in the elderly can be attributed to cancer is not well studied. We assessed the impact of cancer on risk of VTE in young, middle-aged and elderly. 26,094 subjects without a history of cancer or VTE were recruited from the Tromsø study. Incident cancer (n = 2,290) and VTE (n = 531) were recorded from baseline (1994–1995) through December 31st, 2009. Cox regression with cancer as time-varying exposure was used to calculate hazard ratios with 95 % confidence intervals (CI). Overt cancer was associated with a fivefold (95 %CI 4.3, 6.7) increased risk of VTE, with an age-dependent gradient from 26-fold (95 %CI 12.1, 56.5) increased in the young, ninefold (95 % CI 6.6, 12.7) increased in the middle-aged, and threefold (95 % CI 2.5, 4.5) increased risk in the elderly. The population attributable risks were 14, 27 and 18 %, respectively. Conclusion: The relative risk of VTE by cancer were higher in young compared to elderly subjects, but the proportion of VTEs in the population due to cancer did not differ much across age groups. Our findings indicate that the increased risk of VTE by advancing age cannot be attributed to higher incidence of cancer in the elderly. 相似文献
995.
Julie Elbk Pedersen Katrine Strandberg-Larsen Michael Andersson Johnni Hansen 《Scandinavian journal of work, environment & health》2021,47(2):154
Objective:The aim of this study was to explore the association between occupational exposure to diesel exhaust and polycyclic aromatic hydrocarbons (PAH), respectively, and breast cancer subtypes.Methods:The study included 38 375 women <70 years with incident breast cancer, identified in the Danish Cancer Registry, and 5 breast cancer-free controls per case who were randomly selected from the Danish Civil Registration System and matched on year of birth. Full employment history was obtained for all study subjects from a nationwide pension fund, and exposure to diesel exhaust and PAH was assessed using a job exposure matrix. Conditional logistic regression was used for estimation of odds ratios (OR) with adjustment for reproductive factors and socioeconomic status.Results:No noteworthy associations were observed for overall breast cancer in women exposed to diesel exhaust. However, diesel exhaust modestly elevated the risk of estrogen receptor negative breast tumors before age 50 [OR 1.26, 95% confidence interval (CI) 1.09–1.46]. Duration– and dose–response relationships were further observed for this subtype in this age group. No notable risk patterns were generally observed for PAH exposure.Conclusion:Occupational exposure to diesel exhaust may increase the risk of early-onset estrogen receptor negative breast tumors in women. Future studies exploring this association are warranted. 相似文献
996.
Tryptic cleavage of proteinase-activated receptor-2 (PAR2) causes the unmasking of a tethered receptor-activating sequence, S37LIGRLDTP. We sought to determine, in the amino-terminal sequence of the PAR2 tethered ligand, the key amino acid residues that are responsible for receptor activation. Using site-directed mutagenesis, nine PAR2 mutants with alanine substitutions in the first six amino acids of the tethered ligand, S37LIGRL42., were prepared: PAR2S37A, PAR2L38A, PAR2I39A, PAR2G40A, PAR2R41A, PAR2A37-38, PAR2A39-42, PAR2A37,39-42, and PAR2A37-42, along with the reverse-sequence construct, PAR2L37S38. These mutants, together with wild-type PAR2(PAR2wt), were expressed in Kirsten virus-transformed rat kidney cells and were then assessed for receptor-mediated calcium signaling upon activation by trypsin and by receptor-activating peptides like SLIGRL-NH2. In addition, the release of the N-terminal receptor sequence that is cleaved from PAR2 by trypsin activation was monitored in the above cell lines using a site-targeted anti-receptor antibody. All PAR2 constructs were activated by SL-NH2, and all mutated tethered ligand sequences were unmasked by trypsin. However, differential activation of the receptor by trypsin in these mutants was observed: PAR2 mutants PAR2A37-38 and PAR2L37S38, in which the first two amino-terminal tethered ligand residues (S37L38) are either changed to alanines or reversed, yielded little or no response to trypsin, nor did PAR2A37,39-42. However, trypsin activated all other constructs. We conclude that the amino-terminal tethered ligand dipeptide sequence S37L38 plays a major role in the activation of PAR2. 相似文献
997.
El-Emam AA Hansen SH Moustafa MA El-Ashry SM El-Sherbiny DT 《Journal of pharmaceutical and biomedical analysis》2004,34(1):35-44
Two sensitive, simple and specific methods based on spectrophotometry and reversed-phase HPLC with fluorimetric detection are described for the determination of lisinopril in dosage forms as well as in spiked human plasma using solid phase extraction (SPE) procedures. Both methods are based on the derivatization of lisinopril with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 9 to yield a yellow, fluorescent product. The spectrophotometric method depends on measuring the formed yellow color at 470 nm after optimization of the reaction conditions. The HPLC method is based on measurement of the derivatized product using fluorescence detection at 540 nm (excitation at 470 nm). The separation of the derivatized drug, the excess reagent and the internal standard (bumetanide) was performed on a reversed-phase ODS column using isocratic elution with methanol-0.02 M sodium dihydrogen phosphate, pH 3.0 (55:45, v/v) at a flow rate of 1.0 ml/min. The calibration graphs were linear over the concentration ranges 2-20 or 0.02-3.2 microg/ml of lisinopril with minimum detectability of 0.3 and 0.008 microg/ml (6.1 x 10(-7) and 1.7 x 10(-8)M) for the spectrophotometric and the HPLC methods, respectively. The proposed methods were applied without any interference from the tablet excipients for the determination of lisinopril in dosage forms, either alone or co-formulated with hydrochlorothiazide. Furthermore, the use of the HPLC method was extended to the in vitro determination of the drug in spiked human plasma. Interference from endogenous amino acids has been overcomed by using the solid phase extraction technique, the percentage recovery (n=6) was 101.6+/-3.35. 相似文献
998.
K. Winther S. Bondesen S. Honoré Hansen E. F. Hvidberg 《European journal of clinical pharmacology》1987,33(4):419-422
Summary We have studied platelet aggregation and fibrinolytic activity in six patients with chronic inflammatory bowel disease treated with 5-aminosalicylic acid (mesalazine).There were no changes in these measurements during normal treatment, i.e. 1.5 g per day with a slow-release formulation, nor after an intravenous dose of 250 mg. Also in vitro tests were negative, in contrast to the inhibition seen with aspirin (acetylsalicylic acid).We conclude that treatment with mesalazine does not constitute a hazard to these patients in regard to prolonged bleeding time caused by an influence on platelet aggregation or fibrinolytic activity. 相似文献
999.
Microbial transformation of the antihistamine pyrilamine maleate. Formation of potential mammalian metabolites 总被引:1,自引:0,他引:1
E B Hansen C E Cerniglia W A Korfmacher D W Miller R H Heflich 《Drug metabolism and disposition》1987,15(1):97-106
Fourteen fungi were found to metabolize pyrilamine (2-[(2-dimethylaminoethyl)(p-methoxybenzyl)amino]pyridine). Two Cunninghamella elegans strains transformed essentially all of the pyrilamine added after 144 hr. After 48 hr of incubation, C. elegans ATCC 9245 metabolized 76% of the antihistamine into methylene chloride-extractable pyrilamine metabolites. These organic-soluble metabolites were isolated by HPLC and the major metabolites were characterized by comparison of their chromatographic, mass, and 1H-NMR spectral properties with those of authentic compounds. The major metabolite was identified as 2-[(2-dimethyloxyaminoethyl)(p-methoxybenzyl)amino]pyridine (N-oxide derivative of pyrilamine). Other metabolites identified were 2-[(2-dimethylaminoethyl)(p-hydroxybenzyl)amino]pyridine, 2-[(2-methylaminoethyl)(p-methoxybenzyl)amino]pyridine, and 2-[(2-methylaminoethyl)(p-hydroxybenzyl)amino]pyridine. These metabolites represent O-demethylated, N-demethylated, and O- and N-demethylated derivatives of pyrilamine, respectively. The mutagenic activities of the N-oxide and the N- and O-dealkylated pyrilamine derivatives, and pyrilamine maleate were measured by reversion of Salmonella typhimurium strains TA97, TA98, TA100, and TA102. Pyrilamine maleate and the three microbial metabolites showed no appreciable mutagenic activity in any of the S. typhimurium tester strains. The metabolism of pyrilamine by 12 other filamentous fungi and yeast strains was much less when compared to C. elegans and ranged from 3.8% to 12.2%. The fungal metabolism of pyrilamine may be useful in predicting results of mammalian metabolism and in readily providing sufficient quantities of metabolites for further toxicological studies. 相似文献
1000.
Tagmose TM Schou SC Mogensen JP Nielsen FE Arkhammar PO Wahl P Hansen BS Worsaae A Boonen HC Antoine MH Lebrun P Hansen JB 《Journal of medicinal chemistry》2004,47(12):3202-3211
Phenylcyanoguanidines substituted with lipophilic electron-withdrawing functional groups, e.g. N-cyano-N'-[3,5-bis-(trifluoromethyl)phenyl]-N' '-(cyclopentyl)guanidine (10) and N-cyano-N'-(3,5-dichlorophenyl)-N' '-(3-methylbutyl)guanidine (12) were synthesized and investigated for their ability to inhibit insulin release from beta cells, to repolarize beta cell membrane potential, and to relax precontracted rat aorta rings. Structural modifications gave compounds, which selectively inhibit insulin release from betaTC6 cells (e.g. compound 10: IC(50) = 5.45 +/- 1.9 microM) and which repolarize betaTC3 beta cells (10: IC(50) = 4.7 +/- 0.5 microM) without relaxation of precontracted aorta rings (10: IC(50) > 300 microM). Inhibition of insulin release from rat islets was observed in the same concentration level as for betaTC6 cells (10: IC(50) = 1.24 +/- 0.1 microM, 12: IC(50) = 3.8 +/- 0.4 microM). Compound 10 (10 microM) inhibits calcium outflow and insulin release from perifused rat pancreatic islets. The mechanisms of action of 10 and 12 were further investigated. The compounds depolarize mitochondrial membrane from smooth muscle cells and beta cell and stimulate glucose utilization and mitochondrial respiration in isolated liver cells. Furthermore, 10 was studied in a patch clamp experiment and was found to activate Kir6.2/SUR1 and inhibit Kir6.2/SUR2B type of K(ATP) channels. These studies indicate that the observed effects of the compounds on beta cells result from activation of K(ATP) channels of the cell membrane in combination with a depolarization of mitochondrial membranes. It also highlights that small structural changes can dramatically shift the efficacy of the cyanoguanidine type of selective activators of Kir6.2/SUR2 potassium channels. 相似文献