全文获取类型
收费全文 | 2513篇 |
免费 | 148篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 180篇 |
妇产科学 | 51篇 |
基础医学 | 290篇 |
口腔科学 | 65篇 |
临床医学 | 300篇 |
内科学 | 606篇 |
皮肤病学 | 98篇 |
神经病学 | 93篇 |
特种医学 | 402篇 |
外科学 | 162篇 |
综合类 | 53篇 |
一般理论 | 1篇 |
预防医学 | 141篇 |
眼科学 | 23篇 |
药学 | 126篇 |
2篇 | |
中国医学 | 4篇 |
肿瘤学 | 129篇 |
出版年
2023年 | 9篇 |
2022年 | 15篇 |
2021年 | 22篇 |
2020年 | 18篇 |
2019年 | 23篇 |
2018年 | 47篇 |
2017年 | 31篇 |
2016年 | 31篇 |
2015年 | 48篇 |
2014年 | 66篇 |
2013年 | 86篇 |
2012年 | 77篇 |
2011年 | 72篇 |
2010年 | 113篇 |
2009年 | 95篇 |
2008年 | 72篇 |
2007年 | 126篇 |
2006年 | 80篇 |
2005年 | 81篇 |
2004年 | 41篇 |
2003年 | 48篇 |
2002年 | 43篇 |
2001年 | 47篇 |
2000年 | 39篇 |
1999年 | 39篇 |
1998年 | 130篇 |
1997年 | 157篇 |
1996年 | 134篇 |
1995年 | 111篇 |
1994年 | 115篇 |
1993年 | 102篇 |
1992年 | 41篇 |
1991年 | 40篇 |
1990年 | 44篇 |
1989年 | 59篇 |
1988年 | 53篇 |
1987年 | 46篇 |
1986年 | 53篇 |
1985年 | 47篇 |
1984年 | 29篇 |
1983年 | 23篇 |
1982年 | 27篇 |
1981年 | 29篇 |
1980年 | 29篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 18篇 |
1976年 | 25篇 |
1975年 | 14篇 |
1965年 | 4篇 |
排序方式: 共有2737条查询结果,搜索用时 15 毫秒
81.
Alejandro?álvaro-Meca María?A.?Jiménez-Sousa Dariela?Micheloud Ainhoa?Sánchez-Lopez María?Heredia-Rodríguez Eduardo?Tamayo Salvador?Resino 《Population health metrics》2018,16(1):4
Background
Sepsis has represented a substantial health care and economic burden worldwide during the previous several decades. Our aim was to analyze the epidemiological trends of hospital admissions, deaths, hospital resource expenditures, and associated costs related to sepsis during the twenty-first century in Spain.Methods
We performed a retrospective study of all sepsis-related hospitalizations in Spanish public hospitals from 2000 to 2013. Data were obtained from records in the Minimum Basic Data Set. The outcome variables were sepsis, death, length of hospital stay (LOHS), and sepsis-associated costs. The study period was divided into three calendar periods (2000–2004, 2005–2009, and 2010–2013).Results
Overall, 2,646,445 patients with sepsis were included, 485,685 of whom had died (18.4%). The incidence of sepsis (events per 1000 population) increased from 3.30 (2000–2004) to 4.28 (2005–2009) to 4.45 (2010–2013) (p?<?0.001). The mortality rates from sepsis (deaths per 10,000 population) increased from 6.34 (2000–2004) to 7.88 (2005–2009) to 7.89 (2010–2013) (p?<?0.001). The case fatality rate (CFR) or proportion of patients with sepsis who died decreased from 19.1% (2000–2004) to 18.4% (2005–2009) to 17.9% (2010–2013) (p?<?0.001). The LOHS (days) decreased from 15.9 (2000–2004) to 15.7 (2005–2009) to 14.5 (2010–2013) (p?<?0.001). Total and per patient hospital costs increased from 2000 to 2011, and then decreased by the impact of the economic crisis.Conclusions
Sepsis has caused an increasing burden in terms of hospital admission, deaths, and costs in the Spanish public health system during the twenty-first century, but the incidence and mortality seemed to stabilize in 2010–2013. Moreover, there was a significant decrease in LOHS in 2010–2013 and a decline in hospital costs after 2011.82.
Tamayo J Pérez-Trallero E Gómez-Garcés JL Alós JI;Spanish Group for the Study of Infection in the Primary Health Care Setting 《The Journal of antimicrobial chemotherapy》2005,56(4):780-782
OBJECTIVES: To study the antimicrobial susceptibility and prevalence of the different phenotypes and genotypes of macrolide resistance in group A streptococci isolated in Spain in 2004, and to compare the results with those obtained in 1998 and 2001 using the same methodology and centres. METHODS: A total of 530 unique isolates of Streptococcus pyogenes collected in 21 laboratories from 16 geographic areas (regions) in Spain were used. Antimicrobial susceptibility testing was performed using the agar dilution method. Discs containing erythromycin or clindamycin were used to recognize the phenotypes of macrolide-lincosamide-streptogramin (MLS) resistance. Genes encoding macrolide-lincosamide resistance were detected by PCR. RESULTS: Resistance to erythromycin was 21.7% [95% confidence interval (CI) 16.5-26.3]. The resistance to azithromycin was 21.5%, whereas the resistance to miocamycin and to clindamycin was 6.6% (95% CI 3.0-8.9). Thirty-one (5.8%) of the isolates were resistant to telithromycin. Of the 115 erythromycin-resistant isolates, 67.8% had the M phenotype, representing 14.7% of all the isolates tested. Thirty-five isolates (30.5% of the erythromycin-resistant strains and 6.6% of all the isolates) had the MLS(B) constitutive phenotype. There was a high prevalence of resistance to telithromycin (88.6%) among the 35 strains with the MLS(B) constitutive phenotype. When we compared these results with those from previous studies (1998 and 2001), we found a significant increase in the MLS(B) constitutive phenotype (P < 0.001), and a significant decrease in the M phenotype (P < 0.005) was noted. CONCLUSIONS: The significant increase in the prevalence of resistance to clindamycin and miocamycin, and the prevalence of resistance to telithromycin reached in a short period of time from the introduction of its use, underscore the need for continuous surveillance of antimicrobial resistance in S. pyogenes in Spain. 相似文献
83.
Hiroshi Takakuwa Kazuaki Shimizu Yoshiaki Izumiya Tamayo Kato Izaya Nakaya Hitoshi Yokoyama Ken-ichi Kobayashi Takuyuki Ise 《Hypertension research》2002,25(5):737-742
The purpose of this study was to elucidate the effects of dietary sodium restriction on diurnal blood pressure (BP) variation in primary aldosteronism. We studied the diurnal variation in the systemic hemodynamic indices and in baroreflex sensitivity (BRS). In 13 subjects with aldosterone-producing adenomas (2 males; mean age, 39+/-2 years), intra-arterial pressure was monitored telemetrically on a normal salt diet (NaCl 10-12 g/day). Non-dippers were defined as those with a nocturnal reduction in systolic BP (SBP) of less than 10% of daytime SBP. Ten subjects showed a non-dipper pattern. Six of these "non-dippers" underwent repetitive hemodynamic studies on the last day of a 1-week low salt diet regimen (NaCl 2-4 g/day). Stroke volume was determined using Wesseling's pulse contour method, calibrated with indocyanine green dilution. BRS was calculated every 30 min as delta pulse interval/delta SBP on spontaneous variations. Nocturnal reduction of SBP was 4.1% on the normal salt diet. With sodium restriction, urinary sodium excretion decreased from 187+/-8 to 46+/-8 mmol/day, and body weight decreased from 57.9+/-2.1 to 56.6+/-1.9 kg. Night-time BP significantly decreased with dietary modification from 154+/-7/88+/-4 to 140+/-6/78+/-4 mmHg, whereas daytime BP was unaltered. With sodium restriction, cardiac index and stroke index decreased throughout the day. No significant difference was seen in either daytime or nighttime BRS between the two diets. We conclude that the non-dipper pattern is common in patients with an aldosterone-producing adenoma on a normal salt intake, and under such conditions, volume expansion appears to play a major role in the impairment of nocturnal BP reduction. 相似文献
84.
Arruda VR; Pieneman WC; Reitsma PH; Deutz-Terlouw PP; Annichino-Bizzacchi JM; Briet E; Costa FF 《Blood》1995,86(8):3015-3020
The molecular characterization of the mutations in hemophilia A patients is hampered by the large size of the factor VIII gene and the great heterogeneity of mutations. In this study, we have performed a protocol involving multiplex polymerase chain reaction in which 19 exons were amplified in four different combinations followed by nonradioactive single-strand conformational polymorphism (SSCP) to screen for mutations. Southern blotting was used to detect inversion of the factor VIII gene resulting from recombination between copies of the gene A (F8A) located in intron 22 of the factor VIII gene and two copies close telomeric region of X chromosome. Forty-two hemophilia A patients (21 with severe and 21 with mild-to-moderate disease) were studied. The inversion of factor VIII occurred in 13 of 21 patients affected by severe hemophilia A. One patient showed a large extra band in addition to the three bands observed after Southern blotting with the F8A probe. An abnormal electrophoretic pattern of SSCP was detected in 85% and 50% of the patients affected by mild-to-moderate and severe disease, respectively. Sixteen different mutations were identified. Eleven mutations were novel and comprised 9 point mutations and 2 small deletions. This study shows that the methodology used is safe and rapid and has potential for detecting almost all of the genetic defects of the studied hemophilia A patients. 相似文献
85.
Marsh JC; Will AJ; Hows JM; Sartori P; Darbyshire PJ; Williamson PJ; Oscier DG; Dexter TM; Testa NG 《Blood》1992,79(12):3138-3144
We have used the long-term bone marrow culture (LTBMC) system to analyze hematopoiesis in three patients with dyskeratosis congenita (DC), two of whom had aplastic anemia, and the third had a normal blood count (apart from mild macrocytosis) and normal BM cellularity. Hematopoiesis was severely defective in all three patients, as measured by a low incidence of colony-forming cells and a low level of hematopoiesis in LTBMC. The function of the marrow stroma was normal in its ability to support the growth of hematopoietic progenitors from normal marrows seeded onto them in all three cases, but the generation of hematopoietic progenitors from patients marrow cells inoculated onto normal stromas was reduced, thus suggesting the defect to be of stem cell origin. The parents and unaffected brother of one of the families have also been studied in LTBMC and all showed normal hematopoietic and stromal cell function. From this study we speculate that there are some similarities between DC and the defect in the W/Wv mouse. 相似文献
86.
In clonogenic assays of hematopoietic progenitors, high concentrations (4 U/mL) of erythropoietin (epo) reduced the formation of granulocyte- macrophage (GM) colonies and diminished the number of granulocytes formed per culture plate. Fetal progenitors were more sensitive to these effects of epo than were progenitors from adults, displaying these reductions at greater than or equal to 1 U epo/mL. The mechanism was investigated by growing fetal progenitors stimulated by recombinant GM-CSF, in the absence of epo, and when eight-cell clones first appeared, mapping their location, then adding epo, and assessing its effect on the subsequent differentiation of the clones. In the absence of epo, the clones developed exclusively into GM colonies. However, if developing clones were presented with epo, 85% matured into GM colonies, but 15% became multilineage or normoblast colonies. In addition, developing clones that were presented with epo produced colonies that contained fewer neutrophils. These effects of epo on neutrophil generation were observed with each of three varieties of recombinant epo, and also with purified human epo, but were not observed using epo that had been neutralized with rabbit anti-epo antiserum. 相似文献
87.
Cairo MS; Christensen R; Sender LS; Ellis R; Rosenthal J; van de Ven C; Worcester C; Agosti JM 《Blood》1995,86(7):2509-2515
Neonates, especially those of very low birthweight (VLBW), have an increased risk of nosocomial infections secondary to deficiencies in development. We previously demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) production and mRNA expression from stimulated neonatal mononuclear cells are significantly less than that from adult cells. Recombinant murine GM-CSF administration to neonatal rats has resulted in neutrophilia, increased neutrophil production, and increased survival of pups during experimental Staphylococcus aureus sepsis. In the present study, we sought to determine the safety and biologic response of recombinant human (rhu) GM-CSF in VLBW neonates. Twenty VLBW neonates (500 to 1,500 g), aged < 72 hours, were randomized to receive either placebo (n = 5) or rhuGM-CSF at 5.0 micrograms/kg once per day (n = 5), 5.0 micrograms/kg twice per day (n = 5), or 10 micrograms/kg once per day (n = 5) given via 2-hour intravenous infusion for 7 days. Complete blood counts, differential, and platelet counts were obtained, and tibial bone marrow aspirate was performed on day 8. Neutrophil C3bi receptor expression was measured at 0 and 24 hours. GM-CSF levels were measured by a sandwich enzyme-linked immunosorbent assay at 2, 4, 6, 12, and 24 hours after the first dose of rhuGM-CSF. At all doses, rhuGM-CSF was well tolerated, and there was no evidence of grade III or IV toxicity. Within 48 hours of administration, there was a significant increase in the circulating absolute neutrophil count (ANC) at 5.0 micrograms/kg twice per day and 10.0 micrograms/kg once per day, which continued for at least 24 hours after discontinuation of rhuGM-CSF. When the ANC was normalized for each patient's first ANC, there was a significant increase in the ANC on days 6 and 7 at each dose level. By day 7, all tested doses of rhuGM- CSF resulted in an increase in the absolute monocyte count (AMC) compared with placebo-treated neonates. In those receiving rhuGM-CSF 5.0 micrograms/kg twice per day, there was additionally a significant increase in the day 7 and 8 platelet count. Tibial bone marrow aspirates demonstrated a significant increase in the bone marrow neutrophil storage pool (BM NSP) at 5.0 micrograms/kg twice per day and 10.0 micrograms/kg once per day. Neutrophil C3bi receptor expression was significantly increased 24 hours after the first dose of rhuGM-CSF at 5.0 micrograms/kg once per day. The elimination half-life (T1/2) of rhuGM-CSF was 1.4 +/- 0.8 to 3.9 +/- 2.8 hours.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
88.
Molecular characterization of a high A2 beta thalassemia by direct sequencing of single strand enriched amplified genomic DNA 总被引:2,自引:0,他引:2
Two families, one of Anglo-Saxon-Dutch descent, and the other, West Indian black, have an atypical beta thalassemia characterized by an unusually high level of Hb A2 in the heterozygous state. Restriction endonuclease mapping showed a deletion of about 1.35 kilobase (kb) in the 5' region of the beta globin gene. Direct sequencing of a specific region of genomic DNA amplified by a new modification of the polymerase chain reaction defined the deletion to be 1,393 base pairs (bp) and to be the same in both families. The deletion extends from 485 bp 5' to the mRNA CAP site to the middle of the second intervening sequence. This deletion, together with three others previously described that remove the 5' end of the beta gene but leave the delta gene intact, are all associated with unusually high levels of Hb A2 in the heterozygous state. 相似文献
89.
90.
Four patients with Philadelphia (Ph') positive chronic myeloid leukemia (CML) were studied before, after, and on relapse following allogeneic bone marrow transplantation (BMT). Southern analysis of DNA from cells collected before and at relapse after BMT was performed in order to investigate the origin of the leukemia at relapse. Using minisatellite probes we showed that the relapse occurred in cells of host origin in all four patients and this was confirmed with a Y chromosome specific probe in two male patients who had a female donor. Furthermore, using two probes for the breakpoint cluster region (bcr) on chromosome 22, we showed that leukemic cells at relapse bore identical rearrangements to those in the disease at time of presentation of each patient. We conclude that relapse in all four patients is due to re-emergence of the original leukemic clone. 相似文献