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   135138篇
  免费   10444篇
  国内免费   5960篇
耳鼻咽喉   1781篇
儿科学   1483篇
妇产科学   1988篇
基础医学   19584篇
口腔科学   2728篇
临床医学   15632篇
内科学   22287篇
皮肤病学   2756篇
神经病学   8304篇
特种医学   5891篇
外国民族医学   53篇
外科学   15821篇
综合类   11062篇
现状与发展   22篇
一般理论   36篇
预防医学   7753篇
眼科学   4190篇
药学   13111篇
  68篇
中国医学   4804篇
肿瘤学   12188篇
  2024年   940篇
  2023年   1650篇
  2022年   4424篇
  2021年   6036篇
  2020年   4042篇
  2019年   4101篇
  2018年   4625篇
  2017年   3707篇
  2016年   4274篇
  2015年   6147篇
  2014年   7518篇
  2013年   7359篇
  2012年   11077篇
  2011年   11020篇
  2010年   6625篇
  2009年   5284篇
  2008年   7490篇
  2007年   7029篇
  2006年   6737篇
  2005年   6273篇
  2004年   4690篇
  2003年   4137篇
  2002年   3451篇
  2001年   3137篇
  2000年   3021篇
  1999年   2943篇
  1998年   1644篇
  1997年   1508篇
  1996年   1159篇
  1995年   1074篇
  1994年   910篇
  1993年   610篇
  1992年   920篇
  1991年   811篇
  1990年   751篇
  1989年   667篇
  1988年   615篇
  1987年   547篇
  1986年   425篇
  1985年   375篇
  1984年   249篇
  1983年   196篇
  1982年   97篇
  1981年   109篇
  1980年   70篇
  1979年   145篇
  1978年   90篇
  1975年   61篇
  1974年   87篇
  1973年   69篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Angiographic findings in seventy cases of maxillofacial hemangioma are reported. The tumors have been divided into four types: (1) plexiform hemangioma, (2) cavernous hemangioma with venous drainage, (3) cavernous hemangioma without venous drainage, and (4) the so-called "diffuse type" of cavernous hemangioma. The angiographic features of the four types are described, and clinical application is evaluated. The angiograms demonstrate the location, extent, blood supply, and drainage of the tumors and show whether they communicate intracranially, thus providing valuable criteria for planning and determining the mode of treatment.  相似文献   
92.
Reliability of discrete measurements in caries trials.   总被引:2,自引:0,他引:2  
  相似文献   
93.
OBJECTIVE: The objective of this study was to synthesize and characterize novel 4-arm star-shape poly(acrylic acid)s (poly(AA)s) via atom-transfer radical polymerization (ATRP) technique, tether in situ light-curable methacrylate functionalities onto the poly(AA) backbone, use these star-shape poly(AA)s to formulate the light-cured glass-ionomer cements (LCGICs), and evaluate the mechanical strengths of the formed cements. MATERIALS AND METHODS: The 4-arm poly(AA)s were synthesized using ATRP and tethered with either 2-isocyanatoethyl methacrylate (IEM) or glycidyl methacrylate (GM). The polymers were formulated with 2-hydroxyethyl methacrylte (HEMA) or methacryloyl beta-alanine (MBA), water, initiators, and Fuji II LC filler. Compressive strength (CS) was used as a tool to evaluate the formed cements. The specimens were conditioned in distilled water at 37 degrees C for 24h prior to testing. RESULTS: The 4-arm poly(AA) showed a lower viscosity as compared to its linear counterpart. Both IEM-tethered and GM-tethered 4-arm poly(AA) constructed LCGICs showed significantly high mechanical strengths. Both types of co-monomer and grafting agent dramatically affected the mechanical strengths. The MBA-containing poly(AA) cements exhibited much higher CS than the HEMA-containing cements. The IEM-tethered poly(AA) cements showed much higher CS and DTS than the GM-tethered cements. CONCLUSIONS: This study developed a novel light-curable 4-arm star-shape poly(AA) system. The system was 13% in CS, 178% in DTS and 123% in FS, compared to Fuji II LC.  相似文献   
94.
Park S  Dock M 《Pediatric dentistry》2003,25(4):397-400
This paper presents a case study of a child with xeroderma pigmentosum (XP). The disease results in sensitivity to UV radiation as a result of reduced activity in a defective enzyme responsible for DNA repair. Affected individuals have a variety of clinical symptoms, which may include problems of the skin and oral mucosa, ocular manifestations, and neurologic impairment. A number of precautions must be taken when treating these patients, which include proper shielding from damaging light and the selection of suitable dental materials. The necessary measures required when treating patients with XP are reviewed in this report.  相似文献   
95.
The existence of familial aggregation of mandibular prognathism (MP) suggests that genetic components play an important role in its etiology. In this study, a genome-wide linkage analysis to identify loci susceptible to MP was conducted with 90 affected sibling-pairs in 42 families, comprised of 40 Korean sibling-pairs and 50 Japanese sibling-pairs. Two non-parametric linkage analyses, GENEHUNTER-PLUS and SIBPAL, were applied and detected nominal statistical significance of linkage to MP at chromosomes 1p36, 6q25, and 19p13.2. The best evidence of linkage was detected near D1S234 (maximum Z(lr) = 2.51, P = 0.0012). In addition, evidence of linkage was observed near D6S305 (maximum Z(lr) = 2.23, P = 0.025) and D19S884 (maximum Z(lr) = 1.93, P = 0.0089). Identification of the susceptible genes in the linkage regions will pave the way for insights into the molecular pathways that cause MP, especially overgrowth of the mandible, and may lead to the development of novel therapeutic tools.  相似文献   
96.
口腔颌面部肿瘤化疗方案药物敏感性试验   总被引:1,自引:0,他引:1  
尊文以人舌鳞癌细胞系Tca8113为对象,利用MTT法对口腔颌面部肿瘤化疗常用的八种药物和七种方案进行了药敏试验,ADM、5-Fu、CDDP等抗肿瘤作用较强;而PYM、MTX、VCR单用对Tca8113细胞无明显作用。化疗方案中以MMBD、PF、PVP方案为佳,卡铂与顺铂在此疗方案中的作用无明显差异。实验结果提示:肿瘤化疗不能只凭经验用药,应注意化疗的耐药性问题。  相似文献   
97.
Unilateral coronoid process atrophy associated with fatty degeneration of the masticatory muscles in a 76-year-old woman is reported. CT and plain radiogram findings are presented. The patient had no evidence of collagen disease which often causes osteolysis of the coronoid, process and condyle. Although the true cause of this deformity was unclear, a hypothesis of ischemic changes in the nutrient vessels was suggested as an etiologic factor.  相似文献   
98.
OBJECTIVE: To elucidate the correlations between joint effusion (JE) on T2-weighted magnetic resonance images (MRI) of the temporomandibular joint (TMJ) and the levels of various cytokine receptors, cytokine antagonists, and protein in the synovial fluid of patients with temporomandibular joint disorders (TMD). STUDY DESIGN: Fifty-five TMJs of 55 patients with TMD were scanned by MRI, and synovial fluid samples were obtained on the same day. The grade of JE was evaluated on a scale of 0 to 3: Grades 0 and 1 indicated absence, and grades 2 and 3 indicated the presence of JE. Correlations were evaluated between JE and the concentrations of soluble tumor necrosis factor receptors I and II (sTNFR-I and sTNFR-II, respectively), IL-6 soluble receptor (IL-6sR), IL-1 soluble receptor type II, and IL-1 receptor antagonist and protein in the synovial fluid of patients with TMD. RESULTS: The concentrations of sTNFR-I and protein in the group with JE (18 joints) were significantly higher than in the group without JE (37 joints). In addition, there were significant positive correlations between the grade of JE and the levels of sTNFR-I, sTNFR-II, and protein. CONCLUSIONS: sTNFRs and protein may play important roles in the pathogenesis of TMD. These mediators seem to influence the expression of JE, which may reflect synovial inflammation of the TMJ.  相似文献   
99.
Suppression of residual ridge resorption after tooth extraction is a hot spot in dental research. Recently, simvastatin was reported to influence bone turnover by stimulating bone formation. In this study, the effect of simvastatin application on residual ridge resorption following tooth extraction was investigated. Sixty male Wistar rats were randomly divided into experimental and control groups (n=30). Polylactic acid/polyglycolic acid copolymer carriers, with or without simvastatin, were implanted into extraction sockets of right mandibular incisors. The rats were killed at 1, 2, 4, 8 or 12 weeks after implantation. The relative height of the residual alveolar ridge was significantly greater in the experimental compared to the control group at 2, 4, 8 and 12 weeks. The bone mineral density in the experimental group was significantly higher than that in the control group at 4, 8 and 12 weeks. A larger newly formed bone island was observed in the experimental group at 4 weeks, and higher bone formation rate and quality were found than in the control group at different time points except 1 week. The findings indicate that local application of simvastatin would effectively preserve the residual alveolar bone by promoting bone formation in the extraction socket.  相似文献   
100.
翼外肌上头与颞下颌关节盘关系的研究   总被引:6,自引:1,他引:6  
目的探讨翼外肌上头与关节盘的关系。方法对47侧老年尸体颞下颌关节标本进行了斜矢状面上的解剖学和组织学研究。结果①显微镜下观察翼外肌上头纤维可附着于关节盘、关节囊、关节盘前附着及髁突;②翼外肌上头附着于髁突的纤维平均为52%,附着于关节盘的纤维为10%,附着于关节囊的纤维为24%,附着于下颌前附着的纤维量为4%;③翼外肌上头附着于关节盘的比例与关节盘前移无确切相关性;④翼外肌上头纤维与关节盘纤维的连接方式包括结点连接、肌腱连接和端端连接。结论翼外肌上头主要附着于髁突,附着于关节盘的少量纤维不足以独立地使关节盘发生前移位。  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