全文获取类型
收费全文 | 422篇 |
免费 | 14篇 |
国内免费 | 26篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 11篇 |
基础医学 | 35篇 |
口腔科学 | 9篇 |
临床医学 | 44篇 |
内科学 | 132篇 |
皮肤病学 | 2篇 |
神经病学 | 9篇 |
特种医学 | 90篇 |
外科学 | 44篇 |
综合类 | 16篇 |
预防医学 | 29篇 |
眼科学 | 6篇 |
药学 | 22篇 |
肿瘤学 | 12篇 |
出版年
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2018年 | 3篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 7篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 9篇 |
2007年 | 12篇 |
2006年 | 28篇 |
2005年 | 13篇 |
2004年 | 7篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 16篇 |
1997年 | 5篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 16篇 |
1993年 | 9篇 |
1992年 | 8篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 21篇 |
1988年 | 17篇 |
1987年 | 16篇 |
1986年 | 15篇 |
1985年 | 18篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 10篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1976年 | 3篇 |
1975年 | 5篇 |
1966年 | 3篇 |
1955年 | 2篇 |
1954年 | 2篇 |
1950年 | 2篇 |
1943年 | 2篇 |
排序方式: 共有462条查询结果,搜索用时 15 毫秒
91.
Certain fetal cranial abnormalities found on second-trimester sonograms can be signs of an open spina bifida. In particular, an abnormal configuration of the cerebellum, known as the banana sign, has been associated with neural tube defects. To further evaluate the usefulness of this sign, the authors compared images of the posterior fossa in 23 fetuses who had documented neural tube defects with those of 38 control fetuses who underwent sonography because of an elevated maternal serum alpha-fetoprotein level. Twenty-two of the 23 fetuses with neural tube defects had compression and anterior alignment of the cerebellar hemispheres (the banana sign), and follow-up confirmed the presence of an open neural tube defect. One fetus had a normal-appearing posterior fossa; however, the neural tube defect at birth was completely covered with skin. Four of the neural tube defects were difficult to see sonographically, and the abnormal configuration of the cerebellum, as well as the flattening of the frontal bone (lemon sign), was instrumental in suggesting the correct diagnosis. The 38 control fetuses had normal-appearing posterior fossae. 相似文献
92.
93.
U Poddar BR Thapa K Vaiphei KL Rao SK Mitra K Singh 《Archives of disease in childhood》1998,78(3):264-266
The clinical profile, malignant potential, and management of 17 children with juvenile polyposis (more than five juvenile polyps) were evaluated clinically and endoscopically. Colonoscopy and polypectomy were done three weekly until colonic clearance was achieved, and thereafter two yearly. All polyps were subjected to histological examination. Mean age was 7.7 years, with a male preponderance (3:1). Presentation was with rectal bleeding (94%), pallor (65%), stunted growth (53%), and oedema (47%), and the mean (SD) duration of symptoms was 33 (27) months. None had a positive family history or any congenital anomaly. Two children had six polyps up to the transverse colon; the rest had numerous polyps all over the colon. All children had juvenile polyps on histology and 10 (59%) had adenomatous changes (dysplasia). Total colectomy was done in six for intractable symptoms. Colon clearance was achieved in eight after an average 3.4 polypectomy sessions, and three were still on the polypectomy programme. In conclusion, juvenile polyposis is commonly associated with low grade dysplasia. Serial colonoscopic polypectomy is effective but colectomy is required for intractable symptoms and when clearance of the colon is not possible. 相似文献
94.
Five patients with double outlet right ventricle, ventricular septal defect, pulmonary arterial hypertension and pulmonary vascular obstructive disease and three patients with complete d-transposition of the great arteries, ventricular septal defect, pulonary arterial hypertension and pulmonary vascular obstructive disease underwent an elective Mustard baffle operation. The ventricular septal defect was not closed. A large patent ductus arteriosus was divided in three patients. Seven of the eight patients are alive five to 32 months after surgery; one patient died 11 months after surgery. Cyanosis, dyspnea on exertion, and exercise limitation improved initially in all and has persisted in the survivors. In pre and postoperative hemodynamic studies in four patients, systemic arterial oxygen saturation and effective pulmonary blood flow increased from mean values of 70% to 90% and 1.7/min/m2 to 3.3 L/mon/m2, respectively. Absolute systemic and pulmonary flows, and pressures and resistances, were not significantly altered. Criteria for selection of patients with transposition of the great arteries of double outlet right ventricle who would benefit from a palliative Mustard procedure (Mustard atrial baffle without closure of the ventricular spetal defect) are: 1) severe symptoms; 2) pulmonary arteiral hypertension (75% systemic) with pulmonary vascular obstructive disease; and 3) pulmonary artieral oxygen saturation greater than systemic (ascending aorta) arterial oxygen saturation by approximately 10%. 相似文献
95.
Benacerraf BR; Greene MF; Saltzman DH; Barss VA; Penso CA; Nadel AS; Heffner LJ; Stryker JM; Sandstrom MM; Frigoletto FD Jr 《Radiology》1988,169(3):709-710
Early amniocentesis at 11-14 weeks gestation was evaluated in 100 consecutive patients to see how this technique compares with later amniocentesis. There were no complications as a consequence of the procedure or related pregnancy losses of chromosomally normal fetuses. Samples obtained from three (3%) patients showed insufficient cell growth; two of these patients elected a repeat procedure, which yielded a normal karyotype in each case. There were five abnormal karyotypes, one of which was a culture artifact; in the latter case, repeat amniocentesis at 15 weeks yielded a normal result. Of the 95 pregnancies with normal karyotypes, 94 were progressing normally at follow-up, and one patient elected pregnancy termination because of maternal indications. It appears that early amniocentesis may be an attractive alternative to traditional amniocentesis, in that it provides results at an earlier gestational age and may avoid certain disadvantages of chorionic villus sampling. 相似文献
96.
BR Kurnik RL Allgren FC Genter RJ Solomon ER Bates LS Weisberg 《American journal of kidney diseases》1998,31(4):674-680
Radiocontrast-induced nephropathy (RCIN) is a common cause of hospital-acquired acute renal failure and is associated with a high mortality rate. RCIN is potentially preventable, because administration of the radiocontrast agent is predictable, and a high-risk population has been identified. This multicenter, prospective, randomized, double-blind, placebo-controlled trial was performed to evaluate the efficacy of intravenous atrial natriuretic peptide (anaritide, ANP 4-28) to prevent RCIN. Patients with stable chronic renal failure (serum creatinine greater than 1.8 mg/dL or serum creatinine between 1.5 and 1.8 mg/dL with estimated creatinine clearance of < or = 65 mL/min) were assigned to receive either placebo or one of three doses of anaritide (0.01 microg/kg/min, 0.05 microg/kg/min, or 0.1 microg/kg/min) for 30 minutes before and continuing for 30 minutes after radiocontrast administration. All patients were given intravenous 0.45% saline for 12 hours before the radiocontrast procedure and continuing for 12 hours after the last dose of radiocontrast. Both ionic and nonionic radiocontrast agents were administered. RCIN was defined as either an absolute increase of serum creatinine of > or = 0.5 mg/dL or a percent increase of > or = 25% over baseline. Of the 247 patients who completed the study, 50% had diabetes mellitus. There were no statistical differences in baseline serum creatinine, change in serum creatinine, or the incidence of RCIN. The incidence of RCIN was placebo, 19%; anaritide (0.01), 23%; anaritide (0.05), 23%; anaritide (0.1), 25%. Patients with diabetes mellitus had a significantly greater incidence of RCIN: placebo, 26% versus 9%; anaritide (0.01), 33% versus 13%; anaritide (0.05), 26% versus 21%; anaritide (0.1), 39% versus 8% (diabetic v nondiabetic, P < 0.002). There was no effect in the diabetic or nondiabetic groups by anaritide on the incidence of RCIN. Comparison of the highest-risk group of patients, defined as patients with diabetes mellitus and a baseline serum creatinine > or = 1.8 mg/dL, with the lowest-risk group, defined as patients without diabetes mellitus and a baseline serum creatinine of 1.8 mg/dL or less, did not show a beneficial effect of anaritide administration. In conclusion, administration of intravenous anaritide before and during a radiocontrast study did not reduce the incidence of RCIN in patients with preexisting chronic renal failure, with or without diabetes mellitus. 相似文献
97.
F Laezza BR Gerber JY Lou MA Kozel H Hartman AM Craig DM Ornitz JM Nerbonne 《The Journal of neuroscience》2007,27(44):12033-12044
Fibroblast growth factor 14 (FGF14) belongs to the intracellular FGF homologous factor subfamily of FGF proteins (iFGFs) that are not secreted and do not activate tyrosine kinase receptors. The iFGFs, however, have been shown to interact with the pore-forming (alpha) subunits of voltage-gated Na+ (Na(v)) channels. The neurological phenotypes seen in Fgf14-/- mice and the identification of an FGF14 missense mutation (FGF14(F145S)) in a Dutch family presenting with cognitive impairment and spinocerebellar ataxia suggest links between FGF14 and neuronal functioning. Here, we demonstrate that the expression of FGF14(F145S) reduces Na(v) alpha subunit expression at the axon initial segment, attenuates Na(v) channel currents, and reduces the excitability of hippocampal neurons. In addition, and in contrast with wild-type FGF14, FGF14(F145S) does not interact directly with Na(v) channel alpha subunits. Rather, FGF14(F145S) associates with wild-type FGF14 and disrupts the interaction between wild-type FGF14 and Na(v) alpha subunits, suggesting that the mutant FGF14(F145S) protein acts as a dominant negative, interfering with the interaction between wild-type FGF14 and Na(v) channel alpha subunits and altering neuronal excitability. 相似文献
98.
99.
Epstein-Barr virus associated B cell lymphoproliferative disorders following bone marrow transplantation 总被引:20,自引:7,他引:20
Shapiro RS; McClain K; Frizzera G; Gajl-Peczalska KJ; Kersey JH; Blazar BR; Arthur DC; Patton DF; Greenberg JS; Burke B 《Blood》1988,71(5):1234-1243
B cell lymphoproliferative disorders (BLPD) developed in eight patients following bone marrow transplantation (BMT) for leukemia (five patients) or immunodeficiency (three patients). Recipients of T depleted marrow from a mismatched donor were at particularly high risk of this complication. Six of 25 (24%) recipients of mismatched T depleted bone marrow developed BLPD. In contrast, none of 47 matched T depleted transplants, one of ten (10%) who received non-depleted marrow from an unrelated donor, and only one of 424 matched non-depleted transplants were associated with BLPD. Epstein-Barr virus (EBV) specific serology and DNA hybridization studies demonstrating five to 50 copies of EBV genome/cell in involved tissues implicate this virus as an associated etiologic agent. Restriction fragment length polymorphism (RFLP) and cytogenetic analysis of involved tissue demonstrated donor origin (five of seven) or host origin (two of seven). Histologic appearance was similar to EBV-induced polymorphic B cell proliferations described following solid organ transplantation, or which occur de novo in primary immunodeficiency. Six of seven patients with adequate tissue available for study were found to have monoclonal proliferations by: in situ immunofluorescence (six of seven), and/or immunoglobulin gene rearrangement, (four of six). Cytogenetic analysis of involved tissues from four patients showed a normal karyotype, whereas two had multiple clonal chromosomal abnormalities. Seven patients died despite aggressive attempts at therapy with combinations of antiviral, immunologic, and chemotherapeutic agents. 相似文献
100.
Interleukin-10 administration decreases survival in murine recipients of major histocompatibility complex disparate donor bone marrow grafts 总被引:4,自引:4,他引:4
Studies in mice and humans have indicated that the predominance of interleukin-4 (IL-4)- and IL-10-producing T-helper type 2 (Th2) cells may serve to downregulate acute graft-versus-host disease (GVHD) reactions, whereas IL-2-producing Th1 cells have been implicated in facilitating acute GVHD. We explored the possibility that the in vivo infusion of IL-10 would inhibit acute GVHD induced by fully allogeneic donor grafts. Unexpectedly, IL-10 infusions resulted in a dose- dependent increase in GVHD-induced mortality. The acceleration of lethal GVHD by IL-10 occurred in irradiated recipients of T-cell- depleted bone marrow (BM) plus 5, 15, or 25 x 10(6) splenocytes but did not influence the post-BM transplantation (post-BMT) survival rate of recipients of BM without splenocytes, suggesting that the IL-10 effects were not due to toxicity. Antimurine IL-10-neutralizing monoclonal antibody injections, administered to diminish endogenous IL-10, reduced GVHD-associated mortality and improved the clinical appearance of the recipients. For BM graft rejection studies, IL-10 was infused into sublethally irradiated recipients of anti-Thy 1.2 + C' T-cell-depleted, fully allogeneic BM grafts. In a short-term (day 7) in vivo assay, IL- 10 infusions significantly inhibited allogeneic (but not syngeneic) BM proliferation in vivo, indicative of increased graft rejection. In long- term chimerism experiments, IL-10 infusions caused a significant increase in early post-BMT mortality caused by a profound anemia typically associated with graft rejection and aplasia. A slightly higher irradiation dose (650 cGy v 600 cGy) eliminated the anemia but did not reverse the graft rejection process associated with IL-10 administration. We conclude that the in vivo infusion of exogenous IL- 10 in recipients of fully allogeneic donor grafts results in accelerated GVHD and graft rejection in the strain combinations tested to date. 相似文献