全文获取类型
收费全文 | 1053篇 |
免费 | 70篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 33篇 |
妇产科学 | 36篇 |
基础医学 | 166篇 |
口腔科学 | 52篇 |
临床医学 | 81篇 |
内科学 | 299篇 |
皮肤病学 | 7篇 |
神经病学 | 115篇 |
特种医学 | 11篇 |
外科学 | 132篇 |
综合类 | 5篇 |
一般理论 | 4篇 |
预防医学 | 22篇 |
眼科学 | 59篇 |
药学 | 40篇 |
肿瘤学 | 54篇 |
出版年
2023年 | 3篇 |
2022年 | 7篇 |
2021年 | 13篇 |
2020年 | 11篇 |
2019年 | 12篇 |
2018年 | 17篇 |
2017年 | 11篇 |
2016年 | 26篇 |
2015年 | 12篇 |
2014年 | 32篇 |
2013年 | 38篇 |
2012年 | 58篇 |
2011年 | 63篇 |
2010年 | 31篇 |
2009年 | 47篇 |
2008年 | 64篇 |
2007年 | 76篇 |
2006年 | 71篇 |
2005年 | 78篇 |
2004年 | 108篇 |
2003年 | 71篇 |
2002年 | 72篇 |
2001年 | 20篇 |
2000年 | 7篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 15篇 |
1996年 | 20篇 |
1995年 | 11篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 13篇 |
1991年 | 13篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1974年 | 2篇 |
1972年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有1127条查询结果,搜索用时 0 毫秒
61.
A 14-year-old boy suffered right blunt orbital trauma. X-ray revealed a compressed fracture of the right ethmoidal sinuses. Three months after the trauma, progressive, painless right proptosis developed. Ocular examination revealed a severe proptosis and pronounced down displacement of the right globe without signs of orbital inflammation. A well-demarcated, extraconal right orbital cystic mass was seen on computerized tomography scan. The cyst contents were aspirated and found to contain echinococcal scolices and "hydatid sand." Hypertonic saline was injected and the cyst was excised. Progressive proptosis after blunt orbital trauma in patients from endemic areas should be suspected of being an orbital hydatid cyst. 相似文献
62.
Renal cell carcinoma invading the right ovarian vein: multidetector computed tomography and ultrasound Doppler findings 总被引:1,自引:0,他引:1
Ghersin E Leiderman M Meretik S Kaftori JK Amendola MA Engel A 《Journal of computer assisted tomography》2005,29(4):472-474
Multidetector computed tomography (MDCT) and Doppler ultrasound findings of a renal cell carcinoma invading the right ovarian vein are presented. An MDCT study performed for evaluation of macroscopic hematuria showed a heterogeneously enhancing malignant thrombus in the right ovarian vein that was in continuity with inferior vena cava and right renal vein thrombi of identical characteristics. Further investigation with Doppler ultrasound confirmed these findings and showed arterial blood flow of low resistance within the ovarian vein and inferior vena cava thrombi. To the authors' knowledge, this is the first report of MDCT and Doppler ultrasound findings of a renal cell carcinoma invading the right ovarian vein. 相似文献
63.
The benefit of the operating microscope for access cavity preparation by undergraduate students 总被引:4,自引:0,他引:4
Although studies show the operating microscope (OM) provides benefits for endodontists, the benefit to undergraduates has not been evaluated as completely as for specialists. The purpose of this study was to determine whether using the OM would improve students' performance in endodontic access cavity preparation and canal identification. Thirty-six dental students prepared access cavities and located canals in extracted maxillary molars, before and after training, which varied according to group. The standard group received a lecture and practice in preparation of access cavities. The microscope group received identical instruction using the OM. The control group received lectures only. All groups received equal content and instruction time (2 hr 20 min). Faculty graded preparations according to a multidimensional 5-point rating scale. Using the OM, the microscope group improved significantly in access cavity preparation (p <0.05) and significantly outperformed both standard and control groups in accuracy of identifying canals (p <0.05). 相似文献
64.
This study prospectively assessed the 4 to 8 yr outcome of apical surgery performed by graduate students in phases I and II of the Toronto Study. The study cohort included 155 teeth in 138 patients. Outcome was assessed by a blinded and calibrated examiner. Clinical and radiographic measures were used for a dichotomous outcome: healed (no signs and symptoms, Periapical Index score = 2 or scar), or diseased (presence of signs and symptoms, or Periapical Index score >/= 3). The recall rate was 85% and the overall healed rate 74%. Healed rate was significantly higher for teeth with small (= 5 mm) than larger preoperative lesions (chi, p = 0.02). Logistic Regression revealed an increased odds of disease persistence for teeth with larger preoperative lesions (OR = 3.81, CI = 1.2-12.1), and preoperative root-filling of adequate length (OR = 3.7, CI = 1.1-11.1). Preoperative lesion size and root-filling length were significant predictors of outcome of apical surgery. 相似文献
65.
OBJECTIVE: The purpose of this study was to evaluate the feasibility of obtaining good quality three-dimensional ultrasound pictures of the cranial sutures and fontanelles and to compare between two-dimensional and three-dimensional ultrasound in identifying the normal appearance of cranial sutures and fontanelles by the transvaginal approach at 15 to 16 weeks of gestation. METHODS: Fifty fetuses were prospectively evaluated by two-dimensional and three-dimensional transvaginal sonography between 15 and 16 weeks of gestation. The sagittal, coronal, lambdoidal, and metopic sutures, as well as anterior and posterior fontanelles, were inspected. RESULTS: Three-dimensional ultrasound enabled visualization of all sutures in 37 (74%) fetuses compared to 28 (56%) fetuses examined by two-dimensional ultrasonography (p = NS). The visualization of the sagittal suture was significantly superior by three-dimensional ultrasonography compared to two-dimensional ultrasonography (50 (100%) vs 35 (70%), p < 0.001). No significant difference between the two modalities was found in visualization of the fontanelles. CONCLUSION: Sutures and fontanelles are usually satisfactorily demonstrated by two-dimensional and three-dimensional ultrasound at 15 to 16 weeks of gestation. The sagittal suture is difficult to visualize using two-dimensional ultrasound, and three-dimensional ultrasound appears to be the best method for its demonstration. 相似文献
66.
The objective of this study was to define the variables associated with vaginal birth after cesarean section (VBAC) and to develop a scoring system for the prediction of successful VBAC. We searched our computerized database for parturients with a history of one low-transverse cesarean section (CS) who were delivered during the year 2000. Variables were categorized according to the time period in which they were obtained: (1) first prenatal visit, (2) at the onset of labor, and (3) during labor. Univariate and multiple stepwise logistic regression models were fitted to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Of the 475 parturients with a history of one previous CS, 136 underwent elective CS and 339 underwent a trial of VBAC, of whom 82% were successful. Of the variables that can be obtained at the onset of labor, five were significantly associated with successful VBAC: abnormal presentation as the indication for the primary CS (OR, 7.4; 95% CI 2.8 to 19.2), a previous VBAC (OR, 7.2; 95% CI, 2.1 to 24.8), cervical dilation (OR, 2.5; 95% CI, 1.3 to 4.9), gestational age < or = 41 weeks (OR, 2.8; 95% CI, 1.1 to 7.1), and lower gestational age at the primary CS (OR, 1.2; 95% CI, 1.02 to 1.4). In the proposed VBAC score, each of the four most significant variables was assigned a score ranging between 0 and 3 based on the probability for VBAC. A score < or = 2 was associated with a success rate of 42%, a score between 3 and 6 was associated with a rate of 81%, and a score between 7 and 10 was associated with a 98% successful VBAC rate (p < 0001). The proposed VBAC score may help obstetricians when counseling their patients regarding the individual likelihood of a successful VBAC. 相似文献
67.
Sadan O Schejter E Ginath S Bachar R Boaz M Menczer J Glezerman M 《Archives of gynecology and obstetrics》2004,269(3):188-191
Israeli Jewish women are at low risk for cancer of the uterine cervix. In view of absent screening programs in Israel, there are only scarce data available with regard to results of PAP smears. The aim of this study was to assess the incidence of premalignant cervical lesions in the largest sample of PAP smears reported so far from Israel. We retrospectively analyzed the results of 297,849 PAP smears, which had been examined in a single laboratory, during 9 years (1991–1999). The incidence of low- and high-grade squamous intraepithelial was 0.69% and 0.29%, respectively. Our data indicate similar incidence rates for premalignant lesions in Jewish Israeli women as observed in Western countries, but no increase during the study period. In spite of relatively high incidence rates for premalignant lesions of the uterine cervix, the incidence rate for invasive cervical cancer remains conspicuously low. For unknown reason the conversion rate from premalignant cervical lesions to invasive cancer is lower in Israeli Jewish women than in European and North American women. We discuss possible reasons for this phenomenon and suggest that at this time mass screening for cervical cancer in Israel may probably not be justified. 相似文献
68.
69.
70.
Chang PY Mirsalis J Riccio ES Bakke JP Lee PS Shimon J Phillips S Fairchild D Hara Y Crowell JA 《Environmental and molecular mutagenesis》2003,41(1):43-54
The potential health benefits of green tea continue to attract public and scientific interests and are attributed in part to polyphenolic catechin constituents. Polyphenon E (Poly E) is a decaffeinated green tea catechin mixture containing about 50% epigallocatechin gallate and 30% other catechins. We evaluated the toxicity and genotoxicity of Poly E by using two in vitro assays: bacterial mutagenesis in a Salmonella typhimurium-E. coli assay and the L5178Y mouse lymphoma cell thymidine kinase (Tk) gene mutation assay. In addition, we used two in vivo genotoxicity assays: the mouse micronucleus assay and the Big Blue cII transgenic mouse mutation assay. Repeat-dose toxicity evaluations were performed in mice in parallel with the Big Blue transgenic mutation assays. No significant increases in the revertant colonies were found in the bacterial mutagenesis assay, but a significant increase in the mutant frequency (MF) at the Tk locus was observed in the mouse lymphoma test system. We observed toxicity in mice when Poly E was administered at doses of 2,000 mg/kg/day. Lower doses produced no significant increases in micronucleated erythrocytes in the bone marrow of Swiss-Webster mice and no significant increases in cII transgene MF in the liver, lung, or spleen compared with controls. These results indicate that Poly E, although toxic at high doses (2,000 mg/kg/day), poses minimal genotoxic concern. In addition, these studies highlight the importance of using both in vitro and in vivo systems in genetic toxicity screening of pharmaceuticals before they are administered to humans. 相似文献