全文获取类型
收费全文 | 554篇 |
免费 | 56篇 |
国内免费 | 9篇 |
专业分类
儿科学 | 21篇 |
妇产科学 | 9篇 |
基础医学 | 79篇 |
口腔科学 | 14篇 |
临床医学 | 63篇 |
内科学 | 164篇 |
皮肤病学 | 9篇 |
神经病学 | 18篇 |
特种医学 | 99篇 |
外科学 | 54篇 |
综合类 | 37篇 |
预防医学 | 14篇 |
眼科学 | 5篇 |
药学 | 9篇 |
肿瘤学 | 24篇 |
出版年
2019年 | 3篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2015年 | 11篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 2篇 |
2011年 | 10篇 |
2010年 | 21篇 |
2009年 | 20篇 |
2008年 | 10篇 |
2007年 | 19篇 |
2006年 | 20篇 |
2005年 | 5篇 |
2004年 | 14篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 28篇 |
1997年 | 26篇 |
1996年 | 36篇 |
1995年 | 22篇 |
1994年 | 18篇 |
1993年 | 24篇 |
1992年 | 15篇 |
1991年 | 14篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 21篇 |
1987年 | 20篇 |
1986年 | 24篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 19篇 |
1982年 | 8篇 |
1981年 | 17篇 |
1980年 | 13篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 9篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1969年 | 2篇 |
1936年 | 1篇 |
1934年 | 1篇 |
1931年 | 1篇 |
排序方式: 共有619条查询结果,搜索用时 343 毫秒
1.
2.
Repair of large midline incisional hernias with polypropylene mesh: Comparison of three operative techniques 总被引:9,自引:0,他引:9
de Vries Reilingh TS van Geldere D Langenhorst BLAM de Jong D van der Wilt GJ van Goor H Bleichrodt RP 《Hernia》2004,8(1):56-59
Polypropylene mesh is widely used for the reconstruction of incisional hernias that cannot be closed primarily. Several techniques have been advocated to implant the mesh. The objective of this study was to evaluate, retrospectively, early and late results of three different techniques, onlay, inlay, and underlay. The records of 53 consecutive patients with a large midline incisional hernia — 25 women and 28 men, mean age 60.4 (range 28–94) — were reviewed. Polypropylene mesh was implanted using the onlay technique in 13 patients, inlay in 23 patients, and underlay in 17 patients. Either the greater omentum or a polyglactin mesh was interponated between the mesh and the viscera. The records of these 53 patients were reviewed with respect to: size and cause of the hernia, pre- and postoperative mortality and morbidity, with special attention to wound complications. Patients were invited to attend the outpatient clinic at least 12 months after implantation of the mesh for physical examination of the abdominal wall. Postoperative complications occurred in 14 (26.4%) patients. The onlay technique had significantly more complications, as compared to both other techniques. Reherniation occurred in 15 (28.3%) patients. The reherniation rate of the inlay technique was significantly higher than after the underlay technique (44% vs 12%, P=0.03) and tended to be higher than the onlay technique (44% vs 23%, P=0.22). Repair of large midline incisional hernias with the use of a polypropylene mesh carries a high risk of complications and has a high reherniation rate. The underlay technique seems to be the better technique. 相似文献
3.
Nonheme iron in sickle erythrocyte membranes: association with phospholipids and potential role in lipid peroxidation 总被引:5,自引:0,他引:5
Previous studies documented the abnormal association of heme and heme proteins with the sickle RBC membrane. We have now examined RBC ghosts and inside-out membranes (IOM) for the presence of nonheme iron as detected by its formation of a colored complex with ferrozine. Sickle ghosts have 33.8 +/- 18.2 nmol nonheme iron/mg membrane protein, and sickle IOM have 4.3 +/- 3.0 nmol/mg. In contrast, normal RBC ghosts and IOM have no detectable nonheme iron. The combination of heme and nonheme iron in sickle IOM averages nine times the amount of membrane- associated iron in normal IOM. Kinetics of the ferrozine reaction show that some of this nonheme iron on IOM reacts slowly and is probably in the form of ferritin, but most (72% +/- 18%) reacts rapidly and is in the form of some other biologic chelate. The latter iron compartment is removed by deferoxamine and by treatment of IOM with phospholipase D, which suggests that it represents an abnormal association of iron with polar head groups of aminophospholipids. The biologic feasibility of such a chelate was demonstrated by using an admixture of iron with model liposomes. Even in the presence of tenfold excess adenosine diphosphate, iron partitions readily into phosphatidylserine liposomes; there is no detectable association with phosphatidylcholine liposomes. To examine the bioavailability of membrane iron, we admixed membranes and t-butylhydroperoxide and found that sickle membranes show a tenfold greater peroxidation response than do normal membranes. This is not due simply to a deficiency of vitamin E, and this is profoundly inhibited by deferoxamine. Thus, while thiol oxidation in sickle membranes previously was shown to correlate with heme iron, the present data suggest that lipid peroxidation is related to nonheme iron. In control studies, we did not find this pathologic association of nonferritin, nonheme iron with IOM prepared from sickle trait, high-reticulocyte, postsplenectomy, or iron-overloaded individuals. These data provide additional support for the concept that iron decompartmentalization is a characteristic of sickle RBCs. 相似文献
4.
5.
Antibiotic prophylaxis in permanent pacemaker implantation: a prospective randomised trial. 总被引:6,自引:5,他引:1 下载免费PDF全文
J P Mounsey M J Griffith M Tynan F K Gould A F MacDermott R G Gold R S Bexton 《Heart (British Cardiac Society)》1994,72(4):339-343
BACKGROUND--Pacemaker pocket infection is a potentially serious problem after permanent pacemaker implantation. Antibiotic prophylaxis is commonly prescribed to reduce the incidence of this complication, but current trial evidence of its efficacy is conflicting. A large prospective randomised trial was therefore performed of antibiotic prophylaxis in permanent pacemaker implantation. The intention was firstly to determine whether antibiotic prophylaxis is efficacious in these patients and secondly to identify which patients are at the highest risk of infection. METHODS--A prospective randomised open trial of flucloxacillin (clindamycin if the patient was allergic to penicillin) v no antibiotic was performed in a cohort of patients undergoing first implantation of a permanent pacing system over a 17 month period. Intravenous antibiotics were started at the time of implantation and continued for 48 hours. The trial endpoint was a repeat operation for an infective complication. RESULTS--473 patients were entered into a randomised trial. 224 received antibiotic prophylaxis and 249 received no antibiotics. A further 183 patients were not randomised but were treated according to the operator's preference (64 antibiotics, 119 no antibiotics); these patients are included only in the analysis of predictors of infection. Patients were followed up for a mean (SD) of 19(5) months. Among the patients in the randomised group there were nine infections requiring a repeat operation, all in the group not receiving antibiotic (P = 0.003). In the total patient cohort there were 13 infections, all but one in the non-antibiotic group (P = 0.006). Nine of the infections presented as erosion of the pulse generator or electrode, three as septicaemia secondary to Staphylococcus aureus, and one as a pocket abscess secondary to Staphylococcus epidermidis. Infections were significantly more common when the operator was inexperienced (< or = 100 previous patients), the operation was prolonged, or after a repeat operation for non-infective complications (principally lead displacement). Infection was not significantly more common in patients identified preoperatively as being at high risk (for example patients with diabetes mellitus, patients receiving long term steroid treatment), although there was a trend in this direction. CONCLUSIONS--Antibiotic prophylaxis significantly reduced the incidence of infective complications requiring a repeat operation after permanent pacemaker implantation. It is suggested that antibiotics should be used routinely. 相似文献
6.
7.
8.
9.
Increased spontaneous secretion of rheumatoid factor by intestinal lamina propria mononuclear cells from Crohn's disease but not ulcerative colitis patients. 总被引:1,自引:0,他引:1 下载免费PDF全文
R P MacDermott S Schreiber G S Nash W J Koopman 《Clinical and experimental immunology》1993,92(1):152-157
Increased levels of rheumatoid factors (RF) have been observed in the serum of Crohn's disease but not ulcerative colitis patients, and have been proposed to relate to an increased state of intestinal lymphocyte activation. We have therefore examined the spontaneous in vitro secretion of RF by intestinal lamina propria mononuclear cells (MNC) isolated from specimens from control and inflammatory bowel disease (Crohn's disease, ulcerative colitis) patients. Normal intestinal lamina propria MNC spontaneously secrete rheumatoid factors of different isotypes during 14 days of in vitro culture (9.7 ng/ml IgA RF, 11.6 ng/ml IgM RF and 64.6 ng/ml IgA anti-Fc (IgG)). In matched studies intestinal MNC isolated from normal large bowel exhibited significantly greater levels of RF synthesis and secretion in vitro than normal small bowel intestinal MNC. A large increase in spontaneous RF secretion was observed from Crohn's disease intestinal MNC (21.4 ng/ml IgA RF, 21.4 ng/ml IgM RF, and 108.15 ng/ml IgA anti-Fc (IgG)), when compared with normal controls. The amount of RF secreted was dependent on the amount of inflammatory activity of the bowel specimens, from which the MNC were isolated (198.3 ng/ml of IgA anti-Fc(IgG) from involved versus 50.0 ng/ml from matched non-involved tissue). Ulcerative colitis MNC released decreased amounts of RF (7.1 ng/ml IgA RF, 6.2 ng/ml IgM RF, and 42.3 ng/ml IgA anti-Fc(IgG)). These observations using isolated intestinal MNC may explain the findings of RF changes in the sera of inflammatory bowel disease patients. Our observations support the hypothesis of a heightened state of activation in normal intestinal lamina propria MNC, which is further increased in active Crohn's disease. The dissimilarities observed between Crohn's disease and ulcerative colitis may indicate fundamental differences in disease pathophysiology and will lead to further studies exploring intestinal immunoregulatory properties of RF. 相似文献
10.
This study analyses the influence of female and male patient age and human
menopausal gonadotrophin (HMG) requirements on clinical pregnancy rates and
live birth rates with ovulation stimulation using HMG in combination with
intrauterine insemination (IUI). In this study, 363 consecutive HMG/IUI
treatment cycles in 184 patients carried out at a university fertility
centre were analysed in a retrospective fashion. The main outcomes measured
were clinical pregnancy rates and live birth rates. Increased female
partner age (> or = 35) and male partner age (> or = 40) were found
to negatively influence pregnancy rates with HMG/ IUI therapy. In addition,
this study demonstrated a critical threshold of HMG requirements beyond
which pregnancy did not occur. No pregnancies occurred in treatment cycles
requiring > 25 ampoules (1875 IU) of menotrophins to achieve follicular
maturity, irrespective of patient age. In conclusion, female partner age,
male partner age, and HMG requirements all significantly influence
pregnancy rates with HMG/IUI therapy.
相似文献