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81.
Identification of Actinobacillus actinomycetemcomitans by leukotoxin gene-specific hybridization and polymerase chain reaction assays. 下载免费PDF全文
Eleven strains of Actinobacillus actinomycetemcomitans isolated from cases of systemic infections, local abscesses, and periodontitis were identified by genetic assays using the leukotoxin gene as the target. We have developed a polymerase chain reaction (PCR) assay, based on the leukotoxin structural gene of this pathogen, which clearly identified all tested strains of A. actinomycetemcomitans and separated them from the closely related Haemophilus aphrophilus as well as other bacterial species. Furthermore, DNA-DNA hybridization was performed with the cloned partial leukotoxin structural gene (lktA) as a probe, which again clearly distinguished A. actinomycetemcomitans from H. aphrophilus, parts of the normal oral flora, and species harboring RTX (repeats in toxin) family-related cytotoxins. The PCR fragment amplified from the leukotoxin structural gene gave results similar to those given by the cloned leukotoxin gene when used as a probe in hybridization experiments. The hybridization and PCR assays described here are fundamental improvements for the identification of A. actinomycetemcomitans. 相似文献
82.
S Haas A Stemberger H M Fritsche D Welzel H Wolf F Lechner G Blümel 《Arzneimittel-Forschung》1987,37(7):839-843
In 160 high risk patients with total hip replacement the antithrombotic efficacy and tolerance of a single daily injection of 1500 aPTT-U (aPTT = activated partial thromboplastin time) low molecular weight heparin plus 0.5 mg dihydroergotamine (HNMD; Embolex NM) was compared with a twice daily application of 5000 IU of the heparin-dihydroergotamine combination Heparin-Dihydergot in a double-blind study. Deep vein thrombosis measured by means of the radiofibrinogen uptake test occurred in 20.5% of patients in both groups. In addition, intra- and postoperative blood loss and the development of hematoma were similar in both groups. Thus, on account of the "once-daily" application HNMD offers some substantial advantages: The stress of the patient in the postoperative convalescence phase can be appreciably lowered and thereby the nursing staff are spared a great deal of work. 相似文献
83.
Dynamic and kinetic differences of the vascular and myocardial effects of calcium antagonists in the rat heart 总被引:3,自引:0,他引:3
We studied the effects of nifedipine, nimodipine, verapamil, D600 (gallopamil), D888 (desmethoxyverapamil), D890 (quaternized verapamil), bepridil, and diltiazem on the coronary flow and the left ventricular pressure in the retrogradely perfused paced rat heart; in addition, we investigated the time course of onset and recovery of these effects. We found a clear difference in potency order for the vascular and cardiac effects as well as widely different kinetics of coronary flow increase and negative inotropic activity. Furthermore, positive inotropism at low doses of some calcium antagonists seemed to be related to the vascular effects of these compounds. We conclude that the rat heart contains a hydrophylic and readily accessible, vascular "dihydropyridine" site and a more hydrophobic, possibly intramembraneous or intracellular, myocardial "verapamil" site with a lower accessibility for verapamil derivatives and bepridil. 相似文献
84.
H. Hafner S. Haas M. Pfeifer-Kurda S. Eichhorn S. Michitsuji 《European archives of psychiatry and clinical neuroscience》1987,236(6):333-342
Summary The unusual finding of an abnormal seasonal distribution of schizophrenic births, showing an excess of 10% in the winter or spring months and an equal deficit in the summer or autumn months, cannot be explained by artefacts. It has not yet been established whether the finding is specific to schizophrenia. We observed an excess of schizophrenic births of some 10% in March to May, significant at the 5% level, and a deficit of approximately the same size in June to August on the birth data of first-admission patients with the clinical diagnosis of schizophrenia. The data, obtained from the Mannheim Psychiatric Case Register, were compared with those of the Mannheim population and a control group matched by birth year and sex. The total population of mentally retarded children aged 7 to 16 years from the Mannheim population showed an excess of some 20% in April to June and an equal deficit in the last two quarters of the year, compared with the Mannheim population of the same birth years. The finding was not significant, but allowance must be made for the low case number of 415. We also compared 3409 first-admission patients with depressive syndromes (ICD 296 and 300.4) and 5615 first-admission patients with the diagnosis of neurosis and personality disorders (ICD 300–302, except 300.4, and 305–309) from the Mannheim Case Register with a control population and a parallel control group. Depressed males showed an excess of births in March to May, which was significant at the 1% level; the birth peak for females was smaller and not significant. The same findings were obtained for the category of neurosis and personality disorders, i.e. an excess of about 10% in March to May for males, significant at the 1% level, and a non-significant excess for females. Our findings are awaiting replication. Causal explanations will be discussed with great reservation. The procreational hypothesis, assuming those factors that lead to an equidirectional seasonal pattern of births with a slight deviation from the average of a year in the general population, to be reinforced in the disease categories mentioned, is regarded as the most simple and plausible explanation. It is based on the assumption that some of the parents of individuals suffering from schizophrenia, mental retardation or probably also some other mental disorders running from generation to generation, have a higher threshold in partner-seeking behaviour, which is overcome more easily in the summer months with the consequence of increased pregnancies. 相似文献
85.
C. Gramsch H. M. Emrich S. John S. Haas H. Beckmann M. Zaudig D. von Zerssen 《Journal of neural transmission (Vienna, Austria : 1996)》1984,60(2):133-141
Summary Synapsin I (Protein I), a neuron-specific phosphoprotein enriched in presynaptic nerve terminals, has been used as a quantitative marker for the density of nerve terminals in five brain regions (caudate nucleus, cingulate gyrus, hippocampus, mesencephalon and putamen) from patients who had suffered from Alzheimer disease/senile dementia of Alzheimer type (AD/ SDAT), from patients with multi-infarct dementia (MID), and from agematched controls. Samples were obtained at autopsy. Lower levels of Synapsin I were observed in the hippocampus of patients with AD/SDAT but not with MID. There were no significant differences in Synapsin I levels between patients and controls in any of the other four brain regions examined. 相似文献
86.
Cancer mortality in relatives of retinoblastoma patients 总被引:3,自引:0,他引:3
L C Strong J Herson C Haas K Elder R Chakraborty K M Weiss P Majumder 《Journal of the National Cancer Institute》1984,73(2):303-311
The risk of other cancers in relatives of retinoblastoma (RTB) patients was determined by a survey of the mortality experience of siblings, parents, parental siblings, and grandparents of all U.S. or Canadian RTB patients referred to The University of Texas M.D. Anderson Hospital and Tumor Institute between 1944 and 1980. Expected mortality was ascertained by the application of age-, sex-, race-, and calendar year-specific U.S. mortality rates to the observed person-years. Among 607 relatives of 33 unilateral-sporadic RTB probands, no excess in cancer deaths was observed (observed/expected = 18/22). Among 733 relatives of 47 bilateral-familial RTB probands, a slight excess in cancer deaths was observed (41/31). A significant excess in cancer deaths was occurred in relatives under age 55 years (18/9) and in fathers (7/1) of the bilateral RTB probands. To determine whether the cancer excess was related to some unique allele associated with second tumors in RTB survivors, the cancer mortality of 203 relatives of the 14 RTB patients with second tumors was examined, and no excess was observed (11/11). To determine whether the excess might be attributable to an unexpressed RTB gene or precursor, the mortality experience was examined in 6 kindreds in which parents, unaffected by RTB, had more than 1 child with RTB. Among these 72 relatives a significant excess in cancer deaths was observed (8/2). The findings demonstrate a modest overall cancer excess in relatives of hereditary RTB patients and suggest it may be attributable to an unexpressed RTB gene or precursor in a small number of kindreds. Mechanisms for an apparent "precursor" might involve a delayed mutation, genetic mosaicism, or a submicroscopic balanced chromosomal translocation. 相似文献
87.
88.
Fish oil (FO) diets are associated with decreased thrombosis, which is though to be related, in part, to changes in platelet and vessel wall prostanoid synthesis. Recently, we found that 13-hydroxyoctadecadienoic acid (13-HODE) synthesized in the vessel wall from linoleic acid (LA, 18:2 n-6) via the lipoxygenase pathway, also decreases platelet/vessel wall interactions. Thus, we determined whether diets containing fish oil, walnut oil (rich in linoleic acid), black currant seed oil (rich in both linoleic and gamma linolenic acids, 18:3 n-6), or lard influenced vessel wall 13-HODE synthesis and platelet/vessel wall adhesion in rabbits. In vivo, vessel wall thrombogenicity was decreased in animals fed the black currant seed oil rich diet for 4 weeks as compared to the control "LARD" diet. This latter effect was better obtained when gamma linoleic acid was present suggesting a secondary effect of this fatty acid. The decreased vessel wall thrombogenicity in those animals, was associated with increased vessel wall 13-HODE synthesis. In contrast, ex vivo platelet adhesivity was significantly decreased in the fish oil diet fed animals, as compared to the control "LARD" diet and correlated with decreased platelet 12-HETE synthesis. We conclude that both fish oil and black currant seed oil rich diets inhibit platelet/vessel wall adhesion; the black current seed oil diet by increasing the availability of linoleic acid for 13-HODE synthesis and inhibiting vessel wall thrombogenicity; the fish oil diet, by inhibiting platelet 12-HETE synthesis and subsequent platelet adhesion. 相似文献
89.
Pb2+ modulates the NMDA-receptor-channel complex 总被引:1,自引:1,他引:0
Vladimir Uteshev Dietrich Büsselberg Helmut L. Haas 《Naunyn-Schmiedeberg's archives of pharmacology》1993,347(2):209-213
Summary The actions of Pb2+ on NMDA channel currents of acutely dissociated hippocampal CA1- and CA3-neurones from adult rats activated by aspartate plus glycine (asp/gly) were examined. A fast reversible and a slow irreversible response to Pb2+ were found. Pb2+ applied simultaneously with asp/gly decreased an inward current. The threshold concentration was below 2 M, the current was reduced > 90% at concentrations over 100 M, The decrease of the asp/gly activated current showed no voltage dependence. Opening of NMDA channels was not necessary for Pb2+-action, as preincubation in 50 M Pb2+-containing external solution for several seconds dramatically reduced the response to asp/gly/Pb2+. This effect was reversed within 2 to 5 s of wash. Presence of Pb2+ or asp/Pb2+ or glycine/Pb2+ in the external solution did not prevent recovery of the NMDA receptor/channel complex from desensitization. Prolonged perfusion of a cell with the asp/gly/Pb2+-containing external solution resulted in an irreversible decrease of the asp/gly current, whereas the amplitude of the asp/gly/Pb2+ response did not change over the duration of an experiment. We conclude that Pb2+ modulates NMDA channel activity via interaction with the NMDA/glycine receptor: as a result the channel current decreases.Abbreviations NMDA
N-methyl-D-aspartate
- LTP
long-term potentiation
- AP5
2-amino-5-phosphonovalerate
- EGTA
ethylene glycol bis(-aminoethylether)-N,N,N,N-tetraacetic acid
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
Correspondence to H. L. Haas at the above address 相似文献
90.
Nonhereditary p53 mutations in T-cell acute lymphoblastic leukemia are associated with the relapse phase 总被引:2,自引:0,他引:2
We have previously reported that greater than 60% of human leukemic T- cell lines possess mutations in the p53 tumor suppressor gene. To determine whether T-cell acute lymphoblastic leukemia (T-ALL) patient samples possess p53 mutations, we screened peripheral blood-and bone marrow-derived leukemia samples, taken at diagnosis and at relapse, for p53 mutations. Exons 4 through 9 and selected intron regions of the p53 gene were analyzed using polymerase chain reaction-single-strand conformation polymorphism and direct sequencing. p53 mutations were found in 0 of 15 T-ALL diagnosis samples, as compared with 10 of 36 (28%) T-ALL relapse samples. To determine whether p53 mutations play a role in the recurrence (relapse) of T-ALL, two special groups of T-ALL patients were studied: (1) a group of 8 relapse patients whose disease was refractory to chemotherapeutic treatment, and (2) a group of 6 "paired" T-ALL cell samples from patients for whom we possess both diagnosis and relapse samples. Three of 8 relapsed patients (37.5%) whose disease was refractory to the reinduction of remission by chemotherapy possessed missense mutations of the p53 gene. All 3 cases had mutations in exon 5. Among the paired samples, 3 of 6 patients harbored p53 mutations at disease recurrence, but possessed only wild- type p53 alleles at diagnosis. One case had mutation on exon 4, 1 case in exon 5, and 1 case in exon 8 with loss of heterozygosity. These data clearly indicate that recurrence of T-ALL is associated with missense mutations in p53. Our results indicate that (1) mutations of p53 do occur in T-ALL in vivo, and such mutations are associated with the relapse phase of the disease; and (2) p53 mutation is involved in the progression of T-ALL. This conclusion is supported by our observation that the introduction of T-ALL-derived mutant p53 expression constructs into T-ALL cell lines further increases their growth rate in culture, enhances cell cloning in methylcellulose, and increases tumor formation in nude mice. 相似文献