首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4619篇
  免费   274篇
  国内免费   30篇
耳鼻咽喉   30篇
儿科学   120篇
妇产科学   129篇
基础医学   676篇
口腔科学   175篇
临床医学   370篇
内科学   1036篇
皮肤病学   120篇
神经病学   339篇
特种医学   288篇
外科学   584篇
综合类   85篇
预防医学   238篇
眼科学   54篇
药学   290篇
中国医学   10篇
肿瘤学   379篇
  2023年   33篇
  2022年   64篇
  2021年   109篇
  2020年   61篇
  2019年   87篇
  2018年   94篇
  2017年   75篇
  2016年   93篇
  2015年   95篇
  2014年   121篇
  2013年   169篇
  2012年   285篇
  2011年   249篇
  2010年   138篇
  2009年   132篇
  2008年   232篇
  2007年   251篇
  2006年   233篇
  2005年   258篇
  2004年   224篇
  2003年   203篇
  2002年   197篇
  2001年   87篇
  2000年   85篇
  1999年   88篇
  1998年   59篇
  1997年   59篇
  1996年   70篇
  1995年   38篇
  1994年   43篇
  1993年   38篇
  1992年   57篇
  1991年   62篇
  1990年   52篇
  1989年   88篇
  1988年   72篇
  1987年   74篇
  1986年   71篇
  1985年   49篇
  1984年   29篇
  1983年   36篇
  1982年   21篇
  1981年   25篇
  1980年   23篇
  1979年   37篇
  1978年   26篇
  1977年   23篇
  1976年   21篇
  1968年   25篇
  1966年   25篇
排序方式: 共有4923条查询结果,搜索用时 0 毫秒
31.
32.
Davis  GD; Fulton  RE; Ritter  DG; Mair  DD; McGoon  DC 《Radiology》1978,128(1):133-144
Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.  相似文献   
33.
34.
We constructed a micro-mainframe-link clinical research system for personal use (Personal Clinical Research System). This system was developed with both a mainframe computer and a personal computer (PC). The prepared programs included a database manager (on the mainframe computer), a user interface program (on the PC), and a communication control program that connected the mainframe computer with the PC. The database on the mainframe computer was constructed by two methods. The first method was to transmit data from the PC to the mainframe computer. The second method was to extract data from the patient information database. Using this system, a physician is able to construct a personal research database that contains interesting data for the physician. In addition, the physician is able to accumulate data on a special field using this system. A discharge summary system is now in operation as an example of this system.  相似文献   
35.
OBJECTIVE: To compare the validity of the Mini Mental State Examination (MMSE) and the Short-Memory Questionnaire (SMQ) as screening tests to detect dementia in the elderly general population. SUBJECTS: Six hundred and sixty-two subjects and their informants from the elderly general population sample who had completed these tests. SETTING: One rural community survey in Japan. METHOD: We used receiver-operating characteristic analysis to compare the performance of the MMSE and the SMQ with the clinical diagnosis of dementia according to DSM-III-R. RESULTS: The areas under the receiver-operating characteristic curve of the MMSE and the SMQ were 0.980 (SE = 0.006) and 0.982 (SE = 0.008), respectively. This differed from chance to a highly significant degree for both the MMSE and the SMQ, but the difference between the two scales was not statistically significant. CONCLUSION: As screening tests to detect dementia in the elderly general population, the SMQ which is assessed by informants demonstrates a statistically significant discriminating ability as well as the MMSE.  相似文献   
36.
PURPOSE: To assess the efficacy of the marine-derived alkaloid ecteinascidin 743 (ET-743) in patients with soft tissue sarcomas that progressed despite prior conventional chemotherapy and to characterize the pharmacokinetic profiles of ET-743 in this patient population. PATIENTS AND METHODS: Thirty-six previously treated soft tissue sarcoma patients from three institutions received ET-743 as a 24-hour continuous intravenous (IV) infusion at a dose of 1,500 microg/m(2) every 3 weeks. Pharmacokinetic studies were also performed. Patients were restaged every two cycles for response by objective criteria. RESULTS: Objective responses were observed in three patients, with one complete response and two partial responses, for an overall response rate of 8% (95% CI, 2% to 23%). Responses were durable for up to 20 months. Two minor responses (43% and 47% tumor reduction) were observed, for an overall clinical benefit rate of 14%. The predominant toxicities were neutropenia and self-limited transaminitis of grade 3 to 4 severity in 34% and 26% of patients, respectively. The estimated 1-year time to progression and overall survival rates were 9% (95% CI, 3% to 27%) and 53% (95% CI, 39% to 73%), respectively. The maximum observed plasma concentration and total plasma clearance of ET-743 (mean +/- standard deviation), 1.04 +/- 0.48 ng/mL and 35.6 +/- 16.2 L/h/m(2), respectively, were consistent with previously reported values from phase I studies of the drug given as a 24-hour IV infusion. CONCLUSION: ET-743 is a promising new option for the management of several histologic subtypes of sarcoma. Durable objective responses were obtained in a subset of sarcoma patients with disease progression despite prior chemotherapy. Additionally, the relatively high survival rate noted in this series of previously treated patients further justifies development of this agent.  相似文献   
37.
BACKGROUND: The use of corticosteroids or cytotoxic/immunosuppressive agents such as cyclophosphamide, chlorambucil, and cyclosporine for the treatment of frequently relapsing nephrotic syndrome (FRNS) is limited because of their adverse effects. This study was conducted to evaluate the efficacy and safety of mizoribine, a relatively new immunosuppressive drug developed in Japan, in children with FRNS. METHODS: A double-blind, placebo-controlled, multicenter trial was carried out in children, from 2 to 19 years old, with FRNS. At relapse, patients were treated with prednisolone. According to a dynamic allocation, mizoribine or a placebo was concurrently administered to each patient. Prednisolone was gradually tapered and discontinued within 12 weeks. The test drug was maintained for 48 weeks. The primary end point was the relapse rate (the total number of relapses/the total treatment days for all patients). Analyses were performed according to the intention-to-treat principle. RESULTS: The primary analysis was conducted on 99 mizoribine- and 98 placebo-treated patients. The relapse rate was lower in the mizoribine group than in the placebo group (0.0055 vs. 0.0067; ratio 0.81, 95% CI, 0.61 to 1.05, P = 0.12). The hazard ratio of the cumulative remission rate between the two groups was 0.79 (95% CI, 0. 57 to 1.08). In the subgroups consisting of patients 10 years old or younger, the relapse rate ratio between the mizoribine subgroup (54 patients) and the placebo subgroup (57 patients) was 0.66 (95% CI, 0. 44 to 0.94, P = 0.017). The hazard ratio of the cumulative remission rate between the two subgroups was 0.56 (95% CI, 0.37 to 0.85, P = 0. 007). Hyperuricemia was the most common adverse event with mizoribine (16%), but was transient. CONCLUSIONS: Compared with the placebo, mizoribine significantly decreased the relapse rate and prolonged the remission period in the subgroup consisting of patients 10 years old or younger. This drug may be useful in young children with FRNS who generally relapse more frequently than older children.  相似文献   
38.
Purpose To evaluate the relationships among histopathological type, clinical malignant grade, and Ki-67 labeling index (LI) in sebaceous gland carcinoma (SGC), conjunctival squamous cell carcinoma (SCC), and conjunctival intraepithelial neoplasia (CIN), with pterygium and normal conjunctiva as controls.Methods This retrospective study was conducted at the Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan. We used tissue specimens obtained from 20 patients (four SGC, four SCC, four CIN, four pterygium, and four normal conjunctiva). Ki-67 immunohistochemical analysis was performed in all 20 cases.Results The Ki-67 labeling index (LI) was 46.1 ± 3.0% (average ± SD) in SGC, 28.4 ± 4.5% in SCC, 20.0 ± 7.2% in CIN, 9.0 ± 2.2% in pterygium, and 6.8 ± 2.3% in normal conjunctiva. Ki-67 LI was significantly (Mann-Whitney U test, P < 0.05) higher in SGC than in SCC, and higher, but not significantly, in SCC than in CIN. Ki-67 LI was significantly (P < 0.05) higher in SCC and CIN than in pterygium.Conclusions These results suggest that Ki-67 LI may be a sensitive marker for ocular malignant tumor grading. Jpn J Ophthalmol 2004;48:524–529 © Japanese Ophthalmological Society 2004  相似文献   
39.
40.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号