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   23621篇
  免费   1149篇
  国内免费   157篇
耳鼻咽喉   247篇
儿科学   657篇
妇产科学   457篇
基础医学   2847篇
口腔科学   726篇
临床医学   1705篇
内科学   6174篇
皮肤病学   318篇
神经病学   2153篇
特种医学   965篇
外科学   3865篇
综合类   86篇
一般理论   10篇
预防医学   1189篇
眼科学   271篇
药学   1355篇
中国医学   57篇
肿瘤学   1845篇
  2023年   185篇
  2022年   366篇
  2021年   821篇
  2020年   444篇
  2019年   648篇
  2018年   859篇
  2017年   558篇
  2016年   629篇
  2015年   739篇
  2014年   983篇
  2013年   1180篇
  2012年   1947篇
  2011年   1869篇
  2010年   1133篇
  2009年   971篇
  2008年   1595篇
  2007年   1553篇
  2006年   1497篇
  2005年   1393篇
  2004年   1211篇
  2003年   1102篇
  2002年   1087篇
  2001年   132篇
  2000年   90篇
  1999年   145篇
  1998年   178篇
  1997年   149篇
  1996年   142篇
  1995年   143篇
  1994年   111篇
  1993年   107篇
  1992年   63篇
  1991年   50篇
  1990年   76篇
  1989年   55篇
  1988年   57篇
  1987年   36篇
  1986年   57篇
  1985年   39篇
  1984年   54篇
  1983年   47篇
  1982年   56篇
  1981年   40篇
  1980年   45篇
  1979年   27篇
  1978年   34篇
  1977年   22篇
  1976年   18篇
  1973年   23篇
  1972年   20篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
21.
OBJECTIVE: The aim of this study was to evaluate the biocompatibility of Portland cement with the addition of iodoform, compared to MTA (ProRoot). STUDY DESIGN: Eighteen Wistar albino rats were divided into 3 groups of 6 animals each. Polyethylene tubes were filled either with freshly mixed MTA or Portland cement mixed with iodoform (20% wt/wt) and implanted subcutaneously. An empty tube served as control. After 7, 30, or 60 days, the implants together with the surrounding tissues were removed in blocks. Sections were evaluated for the presence and thickness of a fibrous capsule, presence of granulation tissue, and the severity of inflammatory response. Data were submitted to nonparametric statistical analysis with individual comparisons between groups at a significance level of P < 0.05. RESULTS: There were no differences between inflammatory responses at 7 and 30 days. After 60 days from surgical removal, there was significantly more tissue reaction to the MTA and Portland cement compared to the control group. CONCLUSION: There were no significant differences regarding inflammatory responses between MTA and Portland cement with iodoform after 7, 30, or 60 days. After 60 days, the fibrous capsule around the Portland cement appeared more organized than tissue surrounding MTA implants. After 60 days, there was still a significantly increased tissue reaction to the 2 cements compared to the empty polyethylene tubes.  相似文献   
22.
23.
This article assesses the effects of lower urinary tract symptoms (LUTS), not including urinary incontinence, on the overall sexual health of women, using literature that includes peer-reviewed articles. This article analyzes a number of studies that provide data on the prevalence and the predictors of sexual function impairment in women with LUTS, such as urinary urgency and frequency, overactive bladder syndrome, and interstitial cystitis. Because case studies provide substantial heterogeneity of outcome measures, this article does not apply meta-analytic techniques to the data. Most of the studies showed that LUTS can have a negative impact on the sexual health of women, sexual pain disorder being the more frequent complaint among patients with bladder dysfunctions.  相似文献   
24.
Septic arthritis of the temporomandibular joint (TMJ) is infrequently reported. We present a case of septic arthritis of the TMJ following the extraction of the left upper second molar that occurred 1 week before beginning of symptoms. No evident predisposing factors were detected. Arthroscopic diagnosis of septic arthritis, lysis and lavage, and capsular stretch were performed. Cultures taken from the TMJ space grew Streptococcus sp. After 1 month of antimicrobial therapy the patient was asymptomatic and mandibular function was normal. Literature related to septic arthritis of TMJ and its treatment was reviewed. Different surgical procedures are available to treat this condition. Arthroscopy should be preferred as initial treatment on account of the possibility of drainage and accurate lavage under direct visualization of joint space, at the same time allowing confirmation of diagnostic hypotheses. Improving joint mobility with lysis of adhesions and capsular stretch in an early stage of disease may be helpful in stopping the fibrosis process.  相似文献   
25.
26.
OBJECTIVE: Early graft failure (EGF) is a life-threatening event still accounting for a significant percentage of early deaths after heart transplantation. We tested whether selected metabolic markers, including high-energy phosphate concentrations measured ex vivo in pre-transplant heart grafts by (31)P magnetic resonance spectroscopy (MRS) are related with early post-transplant outcome. METHODS: During a 3-year period, 26 heart grafts harvested in the vicinity of the transplantation centre were studied. Evaluation of transplantability was done conventionally. (31)P MRS was performed ex vivo approximately 60min after aortic cross-clamp to quantify ATP, P(i) and PCr concentration ratios. A MRS-score was defined as a combination of intracellular pH (pHi) and the PCr/P(i) ratio. EGF was defined as the need to abnormally extend circulatory support or to use more than two inotropes before weaning the patient from CPB after transplantation. The grafts were attributed to three groups as follows: A1, transplanted with uneventful outcome (n=14); A2, transplanted with subsequent EGF (n=3) and B, not suitable for transplantation (n=9). RESULTS: Significant differences between groups existed for the following metabolic markers: PCr/ATP (P=0.013), PCr/P(i) (P=0.0004), pHi (P=0.0016) and MRS-score (P=0.0001). The sensitivity, specificity and positive likelihood ratio for EGF with a MRS-score相似文献   
27.
Abstract Caries experience and enamel fluorosis prevalence in 8-year-old children belonging to different socio-economic classes were determined in two Chilean twin cities that are served by optimally fluoridated community water from the same waterworks facility. Low socio-economic status (LSES) children had a higher mean dm ft and DMFT indices (P<0.001) than high socioeconomic status (HSES) children. Prevalence of enamel fluorosis in the permanent teeth of LSES children was 0.79, significantly higher (X2= 9.0; P<0.003) than the value 0.59 found in HSES children. The proportion of Dean's scores 2. 3, 4 and 5 in first molars, mandibular and maxillary incisors in LSES children was higher than in HSES children (P<0.001). Differences in prevalence and seventy of enamel fluorosis between both groups are tentatively attributed lo a different pattern of tap water and tea consumption at pre-school ages. Suggestions are advanced to minimize the undesirable prevalence and severity of enamel fluorosis.  相似文献   
28.
Abstract: The use of neuromuscular electrical stimulation (NMES) for rehabilitation of gait in spinal patients is widely known. The best results can be obtained with the use of biomechanical sensors and a closed loop NMES system. One of the biggest problems faced in the design of control systems for closed-loop operation, in gait rehabilitation, is the variation of the mechanical conditions during the phases of gait. This work presents a new approach to ease the design of rule-based closed loop systems for operation in conditions such as gait rehabilitation.  相似文献   
29.
Forty patients with chronic hepatitis C (CHC) were included in an open randomized controlled trial of lymphoblastoid α-interferon (L-IFN) versus no treatment. Twenty patients entered each group, and features of therapy and control cases were similar. L-IFN was given in low doses (1.5-4.5 megaunits) for 1 yr. In 16 of 20 patients treated with L-IFN (80%), but in only one of 20 nontreated cases (0.5%; p < 0.001), aminotransferase activities became normal. In four patients there was a reactivation of the disease during treatment after 4, 5, 6, and 8 months with normal aminotransferase levels. A posttherapy reactivation of hepatitis was observed in four additional cases after 1, 1, 1, and 3 months of follow-up. The other eight patients (40%) continued with normal aminotransferase levels for 1.52 ± 0.74 (range, 1-2.1) yr after IFN doses were discontinued. In all treated patients except two nonresponders, but in only one of 20 nontreated cases ( p < 0.001), Knodell's histological activity index decreased. Procollagen type III aminoterminal peptide levels did not change significantly in nontreated and nonresponder patients, diminished slightly in patients with a transient response, and normalized in cases with a long-standing response, suggesting that this serum test may be a reliable marker for monitoring response to IFIN therapy in patients with CHC. Finally, L-IFN treatment induced significant increments in CD4/CD8 index, phytohemagglutinin-induced blastogenesis, and natural killer activity. This study shows that L-IFN diminish inflammatory and fibrogenic activity in most patients with CHC. In 40% of patients treated in this trial, a long-standing remission of the disease was observed.  相似文献   
30.
We introduce a new epithelial ovarian carcinoma cell line (UCI 107) from a patient with papillary adenocarcinoma of the ovary who had not been previously treated. The growth characteristics, chemosensitivity, tumorgenicity, cytogenetics, antigen expression, and receptor status were examined. A standardized photometric assay was implemented to determine the response to single drug agents including doxorubicin (ADR), cisplatin (CDDP), and Taxol. Tumorgenicity was determined utilizing female athymic mice implanted either subcutaneously (sc) or intraperitoneally (ip) with 1 × 107 UCI 107 cells. UCI 107 cells grow rapidly in culture with lag phase of approximately 48 hr, population doubling time of 24-36 hr, and saturation density of 4.8 × 105 cells/cm2. The 50% inhibitory concentration values for the chemotherapeutic agents were 0.170, 0.029, and 0.330 μM for ADR, Taxol, and CDDP, respectively. Nude mice produced ip tumors within 15 days, resulting in death from carcinomatosis 40-45 days postimplantation. Subcutaneous tumor nodules (100 mm3 were observed in nude mice 12-13 days post-tumor implantation reaching a maximum tumor volume of approximately 10,000 mm3 by Day 30. The cytogenetic composite karyotype is as follows: 46, X, der (X) t (X;7) (p11;q22), inv dup (1) (q12;q32), t (6;6;11;22) (p21.3;q16;q23.3;q13.3), del (13) (q14.1). The cell line expresses progesterone receptor, increased levels of p53 protein, and cytokeratins. It does not appear to express Her-2/neu protein, estrogen receptor, nor the CA 125 tumor marker. In conclusion, UCI 107 displays unique cellular properties which make it an attractive model for the study of ovarian cancer.  相似文献   
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