全文获取类型
收费全文 | 11908篇 |
免费 | 889篇 |
国内免费 | 170篇 |
专业分类
耳鼻咽喉 | 370篇 |
儿科学 | 127篇 |
妇产科学 | 212篇 |
基础医学 | 1949篇 |
口腔科学 | 142篇 |
临床医学 | 877篇 |
内科学 | 2555篇 |
皮肤病学 | 459篇 |
神经病学 | 983篇 |
特种医学 | 819篇 |
外科学 | 1564篇 |
综合类 | 53篇 |
一般理论 | 2篇 |
预防医学 | 318篇 |
眼科学 | 268篇 |
药学 | 964篇 |
中国医学 | 125篇 |
肿瘤学 | 1180篇 |
出版年
2024年 | 7篇 |
2023年 | 63篇 |
2022年 | 214篇 |
2021年 | 462篇 |
2020年 | 227篇 |
2019年 | 353篇 |
2018年 | 431篇 |
2017年 | 330篇 |
2016年 | 529篇 |
2015年 | 726篇 |
2014年 | 849篇 |
2013年 | 883篇 |
2012年 | 1260篇 |
2011年 | 1147篇 |
2010年 | 766篇 |
2009年 | 624篇 |
2008年 | 783篇 |
2007年 | 688篇 |
2006年 | 507篇 |
2005年 | 494篇 |
2004年 | 374篇 |
2003年 | 331篇 |
2002年 | 304篇 |
2001年 | 89篇 |
2000年 | 77篇 |
1999年 | 55篇 |
1998年 | 39篇 |
1997年 | 49篇 |
1996年 | 31篇 |
1995年 | 29篇 |
1994年 | 20篇 |
1993年 | 25篇 |
1992年 | 20篇 |
1991年 | 29篇 |
1990年 | 13篇 |
1989年 | 13篇 |
1988年 | 16篇 |
1987年 | 17篇 |
1986年 | 10篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 3篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1974年 | 4篇 |
1971年 | 6篇 |
1968年 | 4篇 |
1966年 | 2篇 |
1905年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
81.
Won-Jea Cho Su-Jeong Yoo Byung-Ho Chung Bo-Gil Choi Seung Hoon Cheon Soon-Ho Whang Sin-Kyu Kim Boo-Hyon Kang Chong-Ock Lee 《Archives of pharmacal research》1996,19(4):321-325
Aiming at the development of anticancer agents by modification of phenolic benzo[c]phenanthridine alkaloid, additional hydroxyl group was put on C10 position of fagaridine (1) by a biomimetic synthetic procedure to afford 10-hydroxyfagaridine (12). All of the synthetic intermediates were also screenedin vitro antitumor activities against five different cell lines as well as12. Among them the representative cytotoxic results are shown as follows;p-quinone (11) [ED50 (A549=0.22 μg/ml), (HCT15=0.21 μg/ml), fagaridine (1) (HCT 15=0.41 μg/ml), olefin (6) (HCT 15=0.06 μg/ml), acetal (7) (SKMEL-2=0.07 μg/ml), dihydrofagaridne (10) (A549=0. 38 μg/ml), 10-hydroxyfagaridine (12) (A 549=0.45 μg/ml). From these observation three main remarks can be drawn; (i) the iminium part of benzo[c]phenanthridine is not essential for showing acitvities, (ii) the additional hydroxyl group did not contribute to enhance the cytotoxicity, (iii) the 3-arylisoquinolin-1(2H)-one derivatives were found to display significantin vitro antitumor activity. 相似文献
82.
Interfractional variation in position of the uterus during radical radiotherapy for cervical cancer. 总被引:4,自引:0,他引:4
BACKGROUND AND PURPOSE: This study was conducted to investigate the positional change of the uterus during radiotherapy which can degrade the accuracy of three-dimensional conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT). PATIENTS AND METHODS: Sixty-six patients received radical radiotherapy for cervical cancer in Samsung Medical Center. For each patient, two MRI scans were taken; one was before beginning radiotherapy and the other was in the third or fourth week of radiotherapy. In T2-weighted MRI images, the positional change of the uterus was quantified by measuring six parameters; the distance from the external uterine opening to the isthmus of the uterus (Dcx), the distance from the isthmus of the uterus to the uterine fundus (Dco), the perpendicular distance of the uterine body to the uterine corpus (Dco-per), the angle between the vertical line and the cervical canal in sagittal images (Acx), the uterine corpus angle from the vertical line in sagittal plan (Aco), the angle between the uterine corpus from an arbitrary bony landmark and a vertical mid line in axial images (Aco-axi) RESULTS: Mean value of change in Dcx+Dco of tumor size during treatment was 8.0 mm in small tumors and 17.9 mm in large tumors. Among 44 anteflexed uterus patients, 5 changed into a retroflexed position. 12 patients (18%) had a greater than 30 degrees variation in any angle. For patients under 60 years, the difference in Acx was statistically significant. CONCLUSIONS: Positional changes of the uterus during radiotherapy should be considered in the treatment planning of 3DCRT or IMRT, particularly in patients under 60 years or those with tumor size greater than 4 cm in diameter. 相似文献
83.
Total vaginal or abdominal hysterectomy was considered an inadequate treatment method for invasive uterine cervix cancer. Usually the procedure was inadvertently performed on patients who were thought preoperatively to have benign or premalignant conditions. Between 1985 and 1993, 64 patients undergoing hysterectomy in the presence of invasive cervical cancer were treated with external radiation therapy and/or intracavitary radiotherapy. Preoperative diagnoses were carcinomain situ(36), severe dysplasia (2), and early invasive cancer (14), and others were benign disease. Overall 5-year survival and relapse-free survival rates were 75.8 and 77.5%, respectively. For patients in retrospective stage IA, IB, and IIB (gross residual after surgery), overall 5-year survival rates were 90.9, 88.8, and 27.9%, respectively. Thirteen patients developed treatment failure; most of them (10/13) were patients with gross residual disease. Patients with early invasive cervical cancer (stage IA) had no treatment-related failure. Prognostic factors affecting survival by univariate analysis were retrospective stage (P= 0.0000) and preoperative diagnosis (P= 0.0021). Tumor histology was marginally significant factor (P= 0.0938). By multivariate analysis, only retrospective stage was significant prognostic factor (P= 0.0001). Adjuvant radiotherapy appears to be an effective treatment method for patients with presumed stage IA and IB after inadvertent hysterectomy. Survival for patients with gross disease remaining after inappropriate hysterectomy is poor. So, early cancer detection and proper management with precise pretreatment staging is necessary to avoid inadherent hysterectomy, especially in cases of gross residual disease. 相似文献
84.
Risk factors for wound infection after cholecystectomy. 总被引:3,自引:0,他引:3
Shih-Chang Chuang King-Teh Lee Wen-Tsan Chang Shen-Nien Wang Kung-Kai Kuo Jong-Shyong Chen Pai-Ching Sheen 《台湾医志》2004,103(8):607-612
BACKGROUND AND PURPOSE: Surgical site infection (SSI) after cholecystectomy is a common problem. The aim of this study was to identify the possible risk factors for the development of SSI. METHODS: 545 consecutive patients who received open (125) or laparoscopic (420) cholecystectomy due to gallbladder disease during the years 1998 to 2000 were included in the study. Potential risk factors including clinical features, biochemical data, and operative types were analyzed by univariate and multivariate analysis. RESULTS: The overall incidence of SSI was 4.4% (24/545). The wound complication rate was significantly lower in the laparoscopic group than in the open group (1.4% vs 14.4%, respectively). Factors associated with SSI found by univariate analysis (p < 0.05) included age, gender, acute cholecystitis, white blood cell count, serum albumin, blood glucose and bilirubin level, type of surgery, operative time and positive bile culture. Stepwise logistic regression analysis showed that abnormal blood glucose [odds ratio (OR), 4.7; 95% confidence interval (CI), 1.6 to 13.5], positive bile culture (OR, 3.5; 95% CI, 1.2 to 10.4), and open cholecystectomy (OR, 4.3; 95% CI, 1.3 to 13.6) were the most significant predictors of SSI. CONCLUSION: Poor control of diabetes mellitus before surgery, positive bile culture and open cholecystectomy significantly increased the rate of SSI. These findings indicate that better control of diabetes mellitus, and appropriate selection of surgical procedure and antibiotic regimen in the management of high-risk patients may reduce the incidence of postoperative SSI. 相似文献
85.
血凝素蛋白裂解位点对H5亚型禽流感病毒侵入细胞的影响 总被引:3,自引:0,他引:3
目的通过RT—PCR反应获得了H5N1亚型禽流感病毒完整的血凝素基因(HA)并克隆到真核表达载体pcDNA3上,通过转染293T细胞进行了瞬时表达验证。方法采用PCR定点突变技术,将其HA基因裂解位点的氨基酸组成由RKKR↓GLF突变为RSSR↓GLF,使其具有低致病性AIV的分子特征,并构建了表达突变后HA基因的真核表达载体pcDNA—Hm。将pcDNA—H5和pcDNA—Hm分别与MuLV假病毒构建体系的两种质粒pHTT60和pHIT111共转染转化了SV40大T抗原的人胚肾细胞293T后,收集转染细胞上清,通过Western—blot和细胞感染性实验来研究假病毒的特性。用缺乏囊膜蛋白和已经证实可以形成MuLV假病毒的水泡性口炎病毒糖蛋白G作为对照。结果转染后形成假病毒进行裂解后进行Westem—blot证明两种HA蛋白都能够整合到各自的假病毒颗粒表面,野生型的HA可以检测到三条带,分别与HA0、HA1和HA2大小相符,而突变后的HAm则仅能检测到一条带,与HA前体大小相符,说明其失去了裂解活性。通过感染293T、COS-7和NIH3T3三种不同的靶细胞后发现野生型的HA所形成的假病毒MuLV—H5具有感染性和泛嗜性,而突变后的HA所形成的假病毒则失去了感染性。结论可以得出HA蛋白裂解位点的氨基酸组成不仅对H5亚型禽流感病毒的致病性有影响,对禽流感病毒侵入细胞也具有至关重要的作用。 相似文献
86.
Is the p53 gene mutation of prognostic value in hepatocellular carcinoma after resection? 总被引:13,自引:0,他引:13
HYPOTHESIS: Mutant p53 gene has lost its tumor suppression function and is considered to be a very important step in hepatocellular carcinoma development. We propose that the mutant p53 gene plays a role in its invasiveness and prognosis after resection. DESIGN: A case-controlled study. SETTING: A referral center. PATIENTS: Seventy-nine consecutive patients who underwent surgical resection for hepatocellular carcinoma entered this study. INTERVENTION: Tissue sections of resected hepatocellular carcinoma (deparaffinized and rehydrated from formalin-fixed and paraffin-embedded sections) were incubated with antihuman p53 monoclonal antibody and immunostained. The p53 result was scored without prior knowledge of the patients' status. A 10% immunopositivity was regarded as the threshold value. MAIN OUTCOME MEASURE: The immunopositive rate of p53 was 69.6% (55 of 79 patients). The clinical variables (age, sex, associated liver cirrhosis, hepatitis B virus infection, hepatitis C virus infection, serum alpha-fetoprotein, and Child-Pugh class); the histological variables (size, capsule, vascular permeation; grade of differentiation, and multinodularity); and postoperative course (recurrence, tumor-free interval, death, and survival period) were correlated with p53 immunopositivity. RESULTS: From univariate analysis, more patients with p53 positivity were male (92.7 vs 0%) (P<.001); had vascular permeation (80% vs 50%) (P =.007) (odds ratio [OR], 4.0); no complete capsule (83.6% vs 62.5%) (P =.04) (OR, 3.1); and daughter nodules (90.9% vs 70.8%) (P =.04) (OR, 4.1) than patients with negative p53 staining. From multivariate analysis, only sex and vascular permeation remained significant (P =.001 and P =.008, respectively). Although more patients with p53 positivity had tumor recurrence (78% vs 50%) (P =.01) and death (64% vs 33%) (P =. 01), the Cox proportional hazards model showed that p53 overexpression had only weak correlations with tumor-free interval and survival time (P =.09 and P =.08, respectively). CONCLUSIONS: Our results show that the biological behavior of the mutant p53 gene is strongly related to the invasiveness of hepatocellular carcinoma and may also influence the postoperative course. We suggest that the immunopositivity of the mutant p53 gene has a predictive role in the prognosis of patients with resected hepatocellular carcinoma. 相似文献
87.
88.
89.
Kavindra Nath David S. Nelson Andrew M. Ho Seung‐Cheol Lee Moses M. Darpolor Stephen Pickup Rong Zhou Daniel F. Heitjan Dennis B. Leeper Jerry D. Glickson 《NMR in biomedicine》2013,26(1):98-105
In vivo 31P MRS demonstrates that human melanoma xenografts in immunosuppressed mice treated with lonidamine (LND, 100 mg/kg intraperitoneally) exhibit a decrease in intracellular pH (pHi) from 6.90 ± 0.05 to 6.33 ± 0.10 (p < 0.001), a slight decrease in extracellular pH (pHe) from 7.00 ± 0.04 to 6.80 ± 0.07 (p > 0.05) and a monotonic decline in bioenergetics (nucleoside triphosphate/inorganic phosphate) of 66.8 ± 5.7% (p < 0.001) relative to the baseline level. Both bioenergetics and pHi decreases were sustained for at least 3 h following LND treatment. Liver exhibited a transient intracellular acidification by 0.2 ± 0.1 pH units (p > 0.05) at 20 min post‐LND, with no significant change in pHe and a small transient decrease in bioenergetics (32.9 ± 10.6%, p > 0.05) at 40 min post‐LND. No changes in pHi or adenosine triphosphate/inorganic phosphate were detected in the brain (pHi, bioenergetics; p > 0.1) or skeletal muscle (pHi, pHe, bioenergetics; p > 0.1) for at least 120 min post‐LND. Steady‐state tumor lactate monitored by 1H MRS with a selective multiquantum pulse sequence with Hadamard localization increased approximately three‐fold (p = 0.009). Treatment with LND increased the systemic melanoma response to melphalan (LPAM; 7.5 mg/kg intravenously), producing a growth delay of 19.9 ± 2.0 days (tumor doubling time, 6.15 ± 0.31 days; log10 cell kill, 0.975 ± 0.110; cell kill, 89.4 ± 2.2%) compared with LND alone of 1.1 ± 0.1 days and LPAM alone of 4.0 ± 0.0 days. The study demonstrates that the effects of LND on tumor pHi and bioenergetics may sensitize melanoma to pH‐dependent therapeutics, such as chemotherapy with alkylating agents or hyperthermia. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
90.