全文获取类型
收费全文 | 761篇 |
免费 | 49篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 97篇 |
妇产科学 | 2篇 |
基础医学 | 47篇 |
口腔科学 | 17篇 |
临床医学 | 77篇 |
内科学 | 116篇 |
皮肤病学 | 6篇 |
神经病学 | 12篇 |
特种医学 | 185篇 |
外科学 | 79篇 |
综合类 | 47篇 |
预防医学 | 18篇 |
眼科学 | 5篇 |
药学 | 36篇 |
1篇 | |
肿瘤学 | 77篇 |
出版年
2022年 | 5篇 |
2021年 | 9篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 12篇 |
2014年 | 6篇 |
2013年 | 8篇 |
2012年 | 17篇 |
2011年 | 14篇 |
2010年 | 15篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 22篇 |
2006年 | 26篇 |
2005年 | 19篇 |
2004年 | 17篇 |
2003年 | 18篇 |
2002年 | 11篇 |
2001年 | 24篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 26篇 |
1997年 | 24篇 |
1996年 | 20篇 |
1995年 | 25篇 |
1994年 | 25篇 |
1993年 | 36篇 |
1992年 | 15篇 |
1991年 | 11篇 |
1990年 | 17篇 |
1989年 | 24篇 |
1988年 | 30篇 |
1987年 | 47篇 |
1986年 | 37篇 |
1985年 | 30篇 |
1984年 | 16篇 |
1983年 | 23篇 |
1982年 | 12篇 |
1981年 | 19篇 |
1980年 | 13篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1933年 | 2篇 |
排序方式: 共有823条查询结果,搜索用时 15 毫秒
61.
Left ventricular volumes measured by MR imaging 总被引:9,自引:0,他引:9
We assessed the potential of proton magnetic resonance (MR) imaging for accurately measuring left ventricular volumes using 15 latex casts of excised human left ventricles. The casts were submerged in water to stimulate the endocardial left ventricular cavity interface in in vivo imaging conditions. Tomographic image sections perpendicular to the long axis of the cast were obtained, spanning each cast from apex to base. Simpson's rule was used to calculate the cast volumes. Correlation between the actual cast volumes (as measured by the displacement method) and the calculated volumes using MR imaging for the 15 casts was excellent. Our data demonstrate that MR imaging accurately measures cardiac chamber volumes in this in vitro model. 相似文献
62.
Percutaneous drainage of chest abscesses in children 总被引:1,自引:0,他引:1
Seven patients ranging in age from 3 to 18 years underwent percutaneous drainage of eight intrathoracic abscesses. Five of the abscesses were mediastinal or paramediastinal and resulted from esophageal perforation or esophageal anastomotic leakage. The abscesses resolved in each case, with a mean catheter drainage time of 28 days and no need for surgical intervention. Three of the abscesses were intrapulmonary, and each lay adjacent to a pleural surface. All three lung abscesses resolved within 19-24 days, without thoracotomy or wedge resection. 相似文献
63.
Yolk sac carcinoma of the testis in children 总被引:2,自引:0,他引:2
We reviewed the records of 11 patients with yolk sac carcinoma of the testis seen at the Children's Hospital of Philadelphia from 1971 through 1983. Each child was less than 2 years old at diagnosis, and each had stage I disease (localized to the testicle). Initial management consisted of radical inguinal orchiectomy in all 11 patients. Four patients then underwent retroperitoneal node dissection and none had pathological evidence of retroperitoneal tumor spread. After primary surgical management 5 patients received no further initial treatment. Of these 5 patients 3 are alive with no evidence of disease at 1.5, 2.7 and 4.5 years after diagnosis. The tumor recurred in 2 patients, 1 of whom was salvaged with pulmonary radiation therapy and chemotherapy. The other 6 patients received chemotherapy postoperatively and only 1 has suffered relapse. Over-all, of 3 patients in whom pulmonary metastases developed 1 died of tumor and 1 died of treatment-related pneumonopathy. Our experience and that of others have led us to conclude that patients with localized disease and normal postoperative serum alpha-fetoprotein levels do not benefit from retroperitoneal node dissection, postoperative abdominal irradiation or chemotherapy. Patients with retroperitoneal nodal involvement, widely metastatic disease or recurrent disease can be treated successfully with chemotherapy and in some cases with radiation therapy. 相似文献
64.
65.
J T Carpenter R V Smalley M Raney C L Vogel R S Weiner 《Cancer treatment reports》1986,70(9):1073-1079
A total of 97 women with good-risk metastatic breast cancer received therapy with cyclophosphamide, doxorubicin, and 5-FU; half of these patients were randomly allocated to receive levamisole, 2.5 mg/kg, 2 days of each week in addition to chemotherapy, while the other half received an identical placebo. Good-risk patients consisted of those with bone-only metastasis, or local chest wall recurrence with or without bone metastasis. No significant difference in response rate, duration of disease control, or survival was observed between the groups. No major toxicity was associated with levamisole. 相似文献
66.
In five patients, aged 4 days to 20 months, the left pulmonary artery was inadvertently ligated at the time of attempted closure of the patent ductus arteriosus. The complication was recognized in these patients between 1 day and 5 years later from findings of chest radiography, two-dimensional echocardiography with spectral analysis of Doppler shifted echoes, and angiography. In three patients, the presence of asymmetric pulmonary blood flow on chest radiographs obtained after surgery initially suggested the diagnosis. In the other two patients with bronchopulmonary dysplasia, the diagnosis was made by means of two-dimensional echocardiography and Doppler spectra in one and angiography in the other. On angiograms, the left pulmonary artery distal to the ligation was visualized by delayed opacification from aortic collaterals in three patients and by means of pulmonary venous wedge injection in one. Radiographic and echocardiographic examination with Doppler spectra may permit prompt diagnosis and early correction of this complication. 相似文献
67.
Head and neck lesions: MR-guided aspiration biopsy 总被引:1,自引:0,他引:1
Duckwiler G; Lufkin RB; Teresi L; Spickler E; Dion J; Vinuela F; Bentson J; Hanafee W 《Radiology》1989,170(2):519-522
Aspiration biopsy guided with computed tomography (CT) has long been a valuable tool in the evaluation of head and neck disease. The ability to obtain diagnoses without the need for surgery has had a significant effect on patient treatment. Magnetic resonance (MR) imaging is now rapidly replacing CT as the primary imaging study for many head and neck diseases. The standard stainless steel needles used for CT-guided biopsy are unsuitable for MR-guided biopsy because significant ferromagnetic artifacts obscure the underlying anatomy. A new needle has recently been designed specifically for use with MR imaging. This needle has far less magnetic susceptibility and therefore does not cause significant image distortion. The authors describe the use of this needle in MR-guided aspiration biopsy of a variety of lesions in the head and neck. 相似文献
68.
Tongue and oropharynx: findings on MR imaging 总被引:6,自引:0,他引:6
Lufkin RB; Wortham DG; Dietrich RB; Hoover LA; Larsson SG; Kangarloo H; Hanafee WN 《Radiology》1986,161(1):69-75
Ten healthy subjects and 44 patients with diseases of the tongue or oropharynx were studied with magnetic resonance (MR) imaging. Axial, coronal, and sagittal images with a thickness of 4 mm were obtained with a pixel size of 0.75 X 0.75 mm on a 256 matrix. Nineteen of the patients underwent computed tomography (CT). Nine of those patients later had surgery, and the specimens were obtained for organ sectioning. These three studies as well as clinical history and physical examination findings were correlated. MR imaging was equal to or better than CT in those patients having both examinations. However, neither CT nor MR allowed recognition of histologic features or detection of microscopic spread of disease. Direct coronal and sagittal imaging planes on MR imaging allowed visualization of intrinsic tongue musculature, not possible with CT; this was important in recognizing subtle tumor extension. For these reasons, MR is the imaging method of choice for studying diseases of the tongue and oropharynx. 相似文献
69.
The cisterna magna is effaced in association with myelomeningocele. The authors retrospectively investigated the size of the fetal cisterna magna as a predictor of fetal myelomeningocele in 67 pregnant women (17-38 menstrual weeks) referred for prenatal sonography because of an elevated serum alpha-fetoprotein level (n = 61) or a suspicion of fetal ventriculomegaly on previously obtained sonograms (n = 6). Twenty fetuses had myelomeningocele, 14 had isolated ventriculomegaly, and 33 were normal. A normal-sized cisterna magna (range, 4-9 mm in depth) was present in all normal fetuses. In 19 of 20 fetuses with myelomeningocele, the views of the posterior fossa were adequate, and in each of these the cisterna magna was effaced (n = 18) or very small (n = 1). The cisterna magna was effaced in five of 13 (38%) fetuses with isolated ventriculomegaly in whom the posterior fossa was adequately imaged. Although effacement of the cisterna magna is a nonspecific finding, the high negative predictive value of this sign is useful during routine screening of the fetal neural axis. 相似文献
70.
Malignant ovarian tumors in children and adolescents 总被引:1,自引:0,他引:1
Eighteen patients aged 4 to 18 years (median, 10 years) were treated at the Children's Cancer Research Center of The Children's Hospital of Philadelphia (CHP) from September 1973 to September 1983 for malignant ovarian tumors. The pathologic categories were endodermal sinus tumor (eight patients), embryonal carcinoma (three patients), pure dysgerminoma (three patients), adenocarcinoma (three patients), and malignant granulosa-cell tumor (one patient). In 1973 and 1975, respectively, two patients with endodermal sinus tumors were treated with surgical removal with or without radiation therapy (RT) and chemotherapy with vincristine (Vc) and actinomycin D+ cyclophosphamide + Adriamycin (Adria Laboratories, Columbus, OH) (ACAdr); both developed local recurrence within 12 months and died of tumor. Since 1977, four of six patients with endodermal sinus tumors have been managed successfully with surgery followed by chemotherapy with cisplatin (P), bleomycin (B), vinblastine (Vb), and ACAdr; none received RT. One died of recurrent tumor and the other died of congestive heart failure attributed to Adriamycin (Adr). All three patients with embryonal carcinoma were well after surgical excision alone (one patient) or surgery and chemotherapy with cisplatin + bleomycin + vinblastine (PBVb) + ACAdr (two patients). Treatment of the remaining seven patients included excision alone (two patients) or excision and chemotherapy (five patients) with various combinations of Vc, ACAdr, and P. One patient with granulosa-theca cell tumor also received whole abdominal RT (3000 rad by external beam), and died of congestive heart failure attributed to Adr. The other six children were free of detectable tumor 16 months to 8 years from diagnosis. Chemotherapy with PBVb and actinomycin D + cyclophosphamide (AC) should be used in the postoperative management of young persons with malignant ovarian tumors. Adr is of doubtful value and may be considerably toxic. RT is of limited use and usually is not indicated. 相似文献