全文获取类型
收费全文 | 3771篇 |
免费 | 270篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 39篇 |
儿科学 | 110篇 |
妇产科学 | 111篇 |
基础医学 | 570篇 |
口腔科学 | 53篇 |
临床医学 | 630篇 |
内科学 | 613篇 |
皮肤病学 | 66篇 |
神经病学 | 423篇 |
特种医学 | 96篇 |
外科学 | 354篇 |
综合类 | 53篇 |
一般理论 | 6篇 |
预防医学 | 402篇 |
眼科学 | 60篇 |
药学 | 231篇 |
中国医学 | 1篇 |
肿瘤学 | 254篇 |
出版年
2023年 | 26篇 |
2022年 | 27篇 |
2021年 | 75篇 |
2020年 | 66篇 |
2019年 | 80篇 |
2018年 | 81篇 |
2017年 | 59篇 |
2016年 | 94篇 |
2015年 | 88篇 |
2014年 | 103篇 |
2013年 | 169篇 |
2012年 | 244篇 |
2011年 | 248篇 |
2010年 | 155篇 |
2009年 | 140篇 |
2008年 | 216篇 |
2007年 | 241篇 |
2006年 | 223篇 |
2005年 | 253篇 |
2004年 | 201篇 |
2003年 | 256篇 |
2002年 | 196篇 |
2001年 | 44篇 |
2000年 | 26篇 |
1999年 | 45篇 |
1998年 | 48篇 |
1997年 | 44篇 |
1996年 | 23篇 |
1995年 | 36篇 |
1994年 | 29篇 |
1993年 | 30篇 |
1992年 | 21篇 |
1990年 | 15篇 |
1989年 | 14篇 |
1988年 | 18篇 |
1987年 | 17篇 |
1986年 | 21篇 |
1985年 | 22篇 |
1984年 | 21篇 |
1983年 | 19篇 |
1982年 | 29篇 |
1981年 | 27篇 |
1980年 | 27篇 |
1979年 | 25篇 |
1978年 | 20篇 |
1977年 | 18篇 |
1976年 | 25篇 |
1975年 | 13篇 |
1974年 | 14篇 |
1970年 | 12篇 |
排序方式: 共有4072条查询结果,搜索用时 31 毫秒
41.
Notfall + Rettungsmedizin - Übelkeit und Erbrechen (Nausea und Vomitus, NV) sind geläufige Symptome in der Notfallmedizin, mit etwa 3–4 % der Behandlungsanlässe auf... 相似文献
42.
Rachel Wuerstlein Nadia Harbeck Eva-Maria Grischke Dirk Forstmeyer Raquel von Schumann Petra Krabisch Kerstin Lüdtke-Heckenkamp Andrea Stefek Oliver Stoetzer Andrea Grafe Gabriele Kaltenecker Helmut Forstbauer Doris Augustin Iris Schrader Joke Tio Ulrike Nitz Oleg Gluz Ronald E. Kates Monika Karla Graeser 《Breast care (Basel, Switzerland)》2021,16(1):50
BackgroundProtroca evaluated the efficacy and safety of primary and secondary prophylaxis of neutropenia with lipegfilgrastim (Lonquex®) in breast cancer patients receiving neoadjuvant or adjuvant chemotherapy (CT).Patients and MethodsOf the 255 patients enrolled, 248 patients were evaluable for the intent-to-treat (ITT) and 194 patients for the per-protocol set. Primary and secondary end points after lipegfilgrastim treatment were assessed.ResultsNine patients of the ITT set receiving lipegfilgrastim as primary prophylaxis (n = 222) had febrile neutropenia of grade 3–4 (5 patients) or infection of grade 3–4 (4 patients); 1/26 of those receiving secondary prophylaxis had an event. Dose reductions were performed in 9.5% of the patients. Postponement of cancer CT cycles for >3 days occurred in <15% of patients; 10.8% (92/851 AEs) and 8% (2/25 SAEs) of documented adverse events and serious adverse events, respectively, were related to lipegfilgrastim.ConclusionsApplication of lipegfilgrastim was effective as primary and secondary prophylaxis in the prevention of CT-induced neutropenia in breast cancer. 相似文献
43.
Specific nutrition and metabolic characteristics of critically ill patients with persistent COVID-19
44.
Andrew A. Fulvini Akaash Tuteja Jianhua Le Barbara A. Pokorny Jeanmarie Silverman Doris Bucher 《Vaccine》2021,39(3):545-553
The only effective measure to decrease morbidity and mortality caused by the influenza virus in the human population is worldwide vaccination. Vaccination produces neutralizing antibodies that target the HA1 subunit of the HA (hemagglutinin) protein and are strain specific. The effectiveness of new influenza vaccines are linked to two factors, the correct prediction of the circulating strains in the population in a particular season and the concentration of the HA1 protein in the vaccine formulation. With the advent of the licensing of quadrivalent vaccines, pharmaceutical manufacturers are under considerable pressure due to time constraints and dedicated resources to deliver 194–198 million doses (2020–2021 U.S. market) of vaccine. Considering the valuable resources needed to produce the influenza vaccine in a timely manner, the efficient quantitation of the HA1 protein (the main component in the influenza vaccine) is required. Currently the only method approved by regulatory agencies for quantitation of the HA antigen in vaccines is the single radial immunodiffusion assay (SRID), an antibody dependent assay that is not time efficient. Time efficient methods that are antibody independent e.g. reverse phase-high performance liquid chromatography (RP-HPLC) or size exclusion-HPLC (SE-HPLC) are available. An improved method implementing reverse phase-ultra performance liquid chromatography (RP-UPLC) has been developed to quantitate the HA1 protein antigen present in the high yield reassortant vaccine seed viruses from influenza A H1N1 and H3N2 subtypes harvested from inoculated embryonated chicken eggs. This method differentiates between high yield and lower yielding reassortants in order to select the best vaccine candidate seed virus with the highest growth ‘in ovo’. This direct capability to monitor the HA1 concentration of potential reassortant seed viruses and to choose the best yielding HA influenza reassortant when faced with multiple viral seed candidates provides a major advantage on the industrial scale to the influenza vaccine process. 相似文献
45.
Marita Fehn Maura A. Farquharson Doris Sautner Wolfgang Saeger Dieter K. Lüdecke Anne M. McNicol 《The Journal of pathology》1993,169(3):335-339
Pro-opiomelanocortin (POMC) mRNA was demonstrated in pituitary adenomas from 16 patients with Cushing's disease and 10 with Nelson's syndrome. The intensity of signal was significantly greater in Nelson's syndrome than in Cushing's disease and there was a trend towards a greater proportion of positive cells. This probably reflects inhibition of POMC gene expression by the high circulating levels of cortisol in Cushing's disease. In the para-adenomatous gland, the intensity of signal was variable in cells showing Crooke's hyaline change, ranging from negative to strongly positive, in keeping with the functional heterogeneity of corticotrophs. In one case, junctional corticotrophs were present and these were more intensely stained than anterior lobe corticotrophs in the same gland. This supports the concept that these cells are subject to different regulatory influences from corticotrophs in the anterior lobe. Whether this is related to differences in embryological origins or to local factors is at present unclear. 相似文献
46.
Ernst Hallier Thomas Langhof Doris Dannappel Monika Leutbecher Klaus Schröder Hans Werner Goergens Andreas Müller Hermann M. Bolt 《Archives of toxicology》1993,67(3):173-178
A hitherto unknown glutathione-S-transferase in human erythrocytes displays polymorphism: three quarters of the population (conjugators) possess, whereas one quarter (non-conjugators) lack this specific activity. A standard method for the identification of conjugators and non-conjugators with the use of methyl bromide and gas chromatography (head space technique) is described. Three substrates of the polymorphic enzyme, methyl bromide, ethylene oxide and dichloromethane (methylene chloride), were incubated in vitro with individual whole blood samples of conjugators and non-conjugators. All three substances led to a marked increase of sister chromatid exchanges (SCE) in the lymphocytes of the non-conjugators but not in those of conjugators. A protective effect of the glutathione-S-transferase activity in human erythrocytes for the cytogenetic toxicity of these chemicals in vitro is thus confirmed. Since the enzyme activity is not found in erythrocytes of laboratory animals, species extrapolations for risk assessment of methyl bromide, ethylene oxide and dichloromethane should be reconsidered. 相似文献
47.
Peter Koch Bob Wilffert Doris Wilhelm Thies Peters 《Naunyn-Schmiedeberg's archives of pharmacology》1990,342(4):454-461
Summary The aim of the present study was to assess the different processes contributing to the contraction induced by noradrenaline (NA, 1 gmol/l) in the rat isolated aorta. Pretreatment with maximally effective concentrations of nifedipine or cromakalim reduced the NA-induced contraction to 80 ± 3.5% or 63 ± 2.0%, respectively, without alteration of the shape of the response. After pretreatment with Mn2+, NA caused a transient phasic contraction followed by a sustained tonic component, comparable to the response obtained in Ca2+-free medium. Ryanodine — in the presence of extracellular Ca2+ — caused a slight increase of resting tension, but did not modify the NA-induced contraction. In Ca2+-free medium the contraction elicited by NA consisted of a transient phasic and a sustained tonic component. The amplitude of the phasic contraction decreased exponentially with the time of exposure to Ca2+-free medium. The phasic component was identified as elicited by Ca2+ released from the sarcoplasmic reticulum (SR) by means of ryanodine. If Ca2+ depleted tissues (80 min in Ca2+-free solution) were exposed to Ca2+ in the presence of Mn2+ or cromakalim, the NA-induced phasic response was inhibited, suggesting that Mn2+ and cromakalim blocked the refilling of the store. It can be concluded that activation of 1-adrenoceptors in the rat aorta by NA elicits Ca2+-entry processes which have a different sensitivity to nifedipine, cromakalim and Mn2+. The Ca2+ released from SR contributes about 20% to the overall contractile response. Our data suggest that the depleted SR can be refilled from the extracellular space via a direct cromakalim- and Mn2+-sensitive pathway.
Send offprint requests to: B. Wilffert at the above address 相似文献
48.
Edward M. Newman Doris G. Villacorte Anna Maria Testi Robert A. Krance Michael B. Harris Y. Ravindranath Donald Pinkel 《Cancer chemotherapy and pharmacology》1990,27(1):60-66
Summary Children with acute lymphocytic leukemia (ALL) in remission were treated with overlapping sequential infusions of methotrexate (MTX) and 1--d-arabinofuranosylcytosine (araC) as part of continuation therapy. The doses and the sequence were chosen to mimic conditions that produced greater than additive antineoplastic activity with these two drugs in preclinical studies. To assess the potential for the drug combination to exhibit greater than additive effect in vivo, we investigated several biochemical parameters that had been associated with synergism in vitro. Because the patients were in remission, the intracellular parameters could only be measured in cytologically normal hematopoietic cells. We observed that (1) the mean plasma concentrations of MTX and araC were above those required to obtain a greater than additive cytotoxicity with the two drugs in tissue culture; (2) MTX did not have a significant antipurine effect in bone marrow mononuclear cells; (3) the mean intracellular concentration of deoxycytidine triphosphate (dCTP) was significantly lower after treatment with the drug combination than after therapy with araC alone; and (4) the ratio of araC triphosphate (araCTP) to dCTP was 2.6 times higher after treatment with the combination than after araC alone. These results indicate that it is possible to achieve in patients the biochemical conditions associated with the greater than additive antineoplastic activity of MTX and araC in vitro.Abbreviations ALL
acute lymphocytic leukemia
- araC
1--d-arabinofuranosyluracil
- araCTP
araC triphosphate
- araU
1--d-arabinofuranosyluracil
- dNTPs
deoxyribonucleoside triphosphates
- MTX
methotrexate
- TCA
trichloroacetic acid
Supported in part by grants from the National Cancer Institute, National Institutes of Health (CA-38 053; CA-33572, CA-32278, CA-38 859, CA-29 691, and CA-30 969). Preliminary reports on the biochemical data were published by E. M. N., A. M. T., and D. P. inProc Am Assoc Cancer Res 24: 133 (1983) and those on the clinical data, by R. A K., E. M. N., D. P. R. B. R., M. B. H., Y. R., and A. I. F. inProc Am Soc Clin Oncol 3: 201 (1984) 相似文献
49.
Lisa Ehrlich Doris Pospiech Upenyu L. Muza Albena Lederer Julia Muche Dieter Fischer Petra Uhlmann Felix Tzschöckell Simon Muench Martin D. Hager Ulrich S. Schubert 《Macromolecular chemistry and physics.》2023,224(1):2200317
Organic, solid-state batteries require efficient solid electrolytes able to provide stable ion conduction. Here, solid electrolytes based on ionic liquid (IL) polymers with chloride counterions as electrolyte materials for batteries are presented. Acrylic monomers with imidazolium substituents with alkyl side groups that are linked by alkyl spacers to the acrylic group are employed. The IL monomers with chloride counterions are either converted by thermally initiated radical polymerization into linear homopolymers or incorporated into polymer networks by UV-initiated copolymerization utilizing a bifunctional, non-ionic cross-linker. Both procedures successfully yielded the desired materials, which is confirmed by NMR spectroscopy (linear homopolymers) or Raman spectroscopy (IL networks). The ionic conductivities at room temperature are measured by Electrochemical Impedance Spectroscopy. The ionic conductivities of the linear homopolymers are in the range of 10−4 to 10−6 S cm−1, while those of the IL networks are about two orders of magnitude lower. They increase to 10−4 S cm−1 at 70 °C. The electrochemical stability is examined by Linear Sweep Voltammetry and is proven in the voltage range of −2 to +2 V. The results reveal that the materials represent promising electrolytes for potential solid-state battery applications. 相似文献
50.
Ad F Roffel Joost H Davids Carolina R S Elzinga Doris Wolf Johan Zaagsma Heinz Kilbinger 《British journal of pharmacology》1997,122(1):133-141
- The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M2-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M2 receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference.
- It was found that tripitramine antagonized methacholine-induced contractions of the guinea-pig lung strip with a pKB value of 8.76±0.05. Both the parallel shifts of the concentration-response curves and the slope of the Schild plot being not significantly different from unity (when antagonist preincubation was for 2 h) indicated the involvement of a single population of receptors in the contractile response. From the pKB values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Roffel et al., 1993), this single population of receptors can only be classified as M2-like.
- Tripitramine antagonized methacholine-induced negative chronotropic and inotropic responses in guinea-pig right and left atria with apparent pKB values of 9.4–9.6. However, such values were only obtained when antagonist preincubation was relatively long and/or antagonist concentration relatively high (e.g. with 1 h at 100 or 300 nM but 3 h at 30 nM). It thus appears that low concentrations of tripitramine do not readily equilibrate with M2 receptors in guinea-pig atria nor with M2-like receptors in the guinea-pig lung strip.
- Tripitramine increased electrical field stimulation-induced cholinergic twitch contractions in guinea-pig trachea in concentrations of 0.3–100 nM, by blocking prejunctional muscarinic inhibitory autoreceptors; with higher concentrations, twitch contractions were progressively diminished, as a result of blocking postjunctional M3 receptors (apparent pKB value 6.07±0.15). The pEC20 value (−log concentration that increases twitch by 20% of maximum) was 8.29±0.08, which would suggest that M4 receptors are involved in this response.
- Oxotremorine-induced inhibition of the release of prelabelled [3H]-acetylcholine from guinea-pig trachea, under conditions where there is no auto-feedback, was blocked by tripitramine (2 h preincubation) with a pKB value of 8.56±0.06. The slope of the corresponding Schild plot was not significantly different from unity, which together with the parallel shifts of the concentration-response curves indicated the involvement of a single muscarinic receptor subtype.
- Since the pKB value for tripitramine at prejunctional receptors in guinea-pig trachea is in between the affinities towards M2 and M4 receptors, correlation plots were constructed to compare the pKB values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Kilbinger et al., 1995) to reported affinities at M1–M4 receptors. This showed rather similar distribution patterns of the data points around the line of equality in the case of M2 and M4 receptor subtypes. However, the correlation coefficient was markedly better for M2 (0.9667) than for M4 (0.5976). Since recent evidence suggests that M4 receptors are not expressed in cholinergic nerves from guinea-pig trachea, it is concluded that prejunctional muscarinic autoinhibitory receptors in this tissue exhibit an atypical M2 type character, with a pharmacological profile distinct from cardiac M2 receptors.