全文获取类型
收费全文 | 3413856篇 |
免费 | 249336篇 |
国内免费 | 10808篇 |
专业分类
耳鼻咽喉 | 45689篇 |
儿科学 | 112201篇 |
妇产科学 | 94458篇 |
基础医学 | 484158篇 |
口腔科学 | 94336篇 |
临床医学 | 320319篇 |
内科学 | 665574篇 |
皮肤病学 | 78101篇 |
神经病学 | 283193篇 |
特种医学 | 129077篇 |
外国民族医学 | 1047篇 |
外科学 | 499543篇 |
综合类 | 71995篇 |
现状与发展 | 6篇 |
一般理论 | 1346篇 |
预防医学 | 272766篇 |
眼科学 | 76561篇 |
药学 | 250064篇 |
13篇 | |
中国医学 | 7483篇 |
肿瘤学 | 186070篇 |
出版年
2019年 | 27662篇 |
2018年 | 38880篇 |
2017年 | 29654篇 |
2016年 | 33907篇 |
2015年 | 38293篇 |
2014年 | 52774篇 |
2013年 | 80436篇 |
2012年 | 107579篇 |
2011年 | 113890篇 |
2010年 | 68280篇 |
2009年 | 64681篇 |
2008年 | 105817篇 |
2007年 | 112031篇 |
2006年 | 113686篇 |
2005年 | 109120篇 |
2004年 | 104677篇 |
2003年 | 100927篇 |
2002年 | 97563篇 |
2001年 | 159201篇 |
2000年 | 163416篇 |
1999年 | 137967篇 |
1998年 | 40269篇 |
1997年 | 35826篇 |
1996年 | 35787篇 |
1995年 | 34516篇 |
1994年 | 31869篇 |
1993年 | 29972篇 |
1992年 | 108339篇 |
1991年 | 104761篇 |
1990年 | 101585篇 |
1989年 | 97754篇 |
1988年 | 89794篇 |
1987年 | 88062篇 |
1986年 | 83065篇 |
1985年 | 79365篇 |
1984年 | 59345篇 |
1983年 | 50664篇 |
1982年 | 30180篇 |
1981年 | 26915篇 |
1979年 | 52962篇 |
1978年 | 37610篇 |
1977年 | 31547篇 |
1976年 | 29793篇 |
1975年 | 31373篇 |
1974年 | 37432篇 |
1973年 | 35840篇 |
1972年 | 33489篇 |
1971年 | 31155篇 |
1970年 | 28843篇 |
1969年 | 27310篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
OBJECTIVE: Transanal endoscopic microsurgery (TEM) is a minimally invasive technique for excision of selected benign and malignant rectal neoplasms. It is considered a safe and effective treatment but recurrence rates of 1-13% are reported for benign lesions. The aim of this study was to assess risk factors for local recurrence of benign rectal lesions and to evaluate mortality and morbidity following TEM. METHOD: Data were prospectively collected from all patients undergoing TEM for benign adenomas from January 1998 to March 2005. The procedure was performed by a single surgeon and patients were regularly followed up. RESULTS: One hundred and forty-six procedures were included, with a median patient age of 74 years (range 22-92 years). The mean lesion area was 16 cm(2) (range 0.3-150 cm(2)) and the median distance from the dentate line was 9 cm (range 0-17 cm). Immediate complications included bleeding (six) and acute urinary retention (six). There has been one (0.68%) procedure-related death. After a median follow up of 39 months (range 4-89 months) there have been seven recurrences (4.8%), recurring at a mean time of 23.3 months (range 5-48 months). Only microscopic involvement of the circumferential resection margin was found to be significantly associated with recurrence (P = 0.0059). Recurrence was not associated with age, size of lesion, previous treatment, severity of dysplasia or use of the harmonic scalpel. CONCLUSION: TEM is a safe and effective treatment for benign rectal adenomas. Circumferential resection margin involvement is associated with recurrence, which tends to occur late. Therefore extended follow up is recommended. 相似文献
992.
Caroline A. Harrison BMedSci MRCS ; Martin J. Heaton MD FRCS ; Christopher M. Layton PhD ; Sheila Mac Neil PhD 《Wound repair and regeneration》2006,14(2):203-209
To produce a stable epidermis, keratinocytes need to be firmly attached to the basement membrane. However, following wounding, keratinocytes are required to develop a migratory phenotype in order to reepithelialize the wound. To investigate some of the issues underlying reepithelialization, we have developed a three-dimensional in vitro model of tissue-engineered skin, comprising sterilized human dermis seeded with human keratinocytes and dermal fibroblasts. Using this model, we have shown that the inclusion of fibroblasts within the model increases the stability of keratinocyte attachment. We have also demonstrated that keratinocyte migration occurs most effectively in the absence of a basement membrane and following the inclusion of fibroblasts in the model. In addition, subjecting the keratinocyte layer to mechanical trauma induces a migratory phenotype. We conclude that this three-dimensional in vitro wound model can be used to increase our understanding of the factors that enhance keratinocyte migration and hence wound healing in vivo. 相似文献
993.
Anthony Z Faranesh Dara L Kraitchman Elliot R McVeigh 《Magnetic resonance in medicine》2006,55(5):1114-1123
The purpose of this work was to investigate the use of an intravascular contrast agent to determine perfusion kinetics in skeletal muscle. A two-compartment kinetic model was used to represent the flux of contrast agent between the intravascular space and extravascular extracellular space (EES). The relationship between the image signal-to-noise ratio (SNR) and errors in estimating permeability surface area product (Ktrans), interstitial volume (ve), and plasma volume (vp) for linear and nonlinear curve-fitting methods was estimated from Monte Carlo simulations. Similar results were obtained for both methods. For an image SNR of 60, the estimated errors in these parameters were 10%, 22%, and 17%, respectively. In vivo experiments were conducted in rabbits to examine physiological differences between these parameters in the soleus (SOL) and tibialis anterior (TA) muscles in the hind limb. Values for Ktrans were significantly higher in the SOL (3.2+/-0.9 vs. 2.0+/-0.5x10(-3) min-1), as were values for vp (3.4+/-0.8 vs. 2.1+/-0.7%). Differences in ve for the two muscles (8.7+/-2.2 vs. 8.5+/-1.6%) were not found to be significant. These results demonstrate that relevant physiological metrics can be calculated in skeletal muscle using MRI with an intravascular contrast agent. 相似文献
994.
Introduction The associations between vitamin D receptor (VDR) Bsm I and Fok I genotypes, parity, and risk of osteoporotic hip fracture were evaluated in a statewide population-based case-control study in Utah.Methods Women age 50–89 years with hip fracture (n=882) were ascertained via surveillance of 18 Utah hospitals from 1997 to 2001. Age-matched controls were randomly selected (n=897). Participants were interviewed in their homes, and blood samples were collected for genotyping.Results In logistic regression analyses that controlled for multiple confounders, Bsm I VDR genotype but not Fok I genotype was associated with risk of osteoporotic hip fracture (OR bb vs. BB genotype: 0.68; 95% CI: 0.50, 0.95). In similar analyses, no overall association was observed between parity status and risk of osteoporotic hip fracture. However, the effect of VDR genotype was modified by parity status. Among nulliparous women (n=140), Bsm I genotype was not associated with risk of hip fracture (OR bb vs. BB: 0.82; 95% CI: 0.28, 2.4); among primiparous women (n=133), bb genotype was associated with increased risk of hip fracture (OR bb vs. BB: 3.30; 95% CI: 0.96, 11.29); among multiparous women (n=1,400), bb genotype was associated with decreased risk of hip fracture (OR bb vs. BB: 0.59; 95% CI: 0.42, 0.84).Conclusion VDR Bsm I genotype was associated with risk of hip fracture in Utah women, and this effect was modified by parity status. Hormonal or lifestyle factors related to parity may underlie this interaction. 相似文献
995.
G Freschi L Landi A Castagnoli A Taddei P Bechi G Bucciarelli 《European journal of surgical oncology》2006,32(5):577-582
AIMS: To report clinical outcomes of a large series of cases with advanced thyroid cancer. STUDY DESIGN: Three hundred and eighty-five patients at the UICC stages III and IV were selected for the study with thyroid cancer. RESULTS: Papillary carcinoma and sclerosing carcinoma have better survival than the Hürthle cell and insular types. Lymphatic metastasis does not appear to worsen the prognosis. All the tumour forms offer the chance of long survival. CONCLUSIONS: Surgical treatment is the primary treatment of thyroid carcinoma. The combined treatments of surgery, metabolic beam therapy, suppressive hormone therapy, radiotherapy and chemotherapy cure a high percentage of patients with the tumour at an advanced stage. 相似文献
996.
L González-Bayón S González-Moreno G Ortega-Pérez 《European journal of surgical oncology》2006,32(6):619-624
The new treatment strategy for Peritoneal Surface Malignancy combines a cytoreductive surgery and perioperative intraperitoneal chemotherapy. Cytoreduction removes all macroscopic tumor. Intraperitoneal chemotherapy avoids implantation of microscopic residual tumor cells on intra-abdominal surfaces when it is administered intraoperatively and/or early in the postoperative period. Delivering cytotoxic drugs directly into the peritoneal cavity maximizes dose intensity and minimizes systemic toxicity. Hyperthermia is selectively cytotoxic for malignant cells and potentiates the effect of chemotherapy. Implementation of this procedure makes the perioperative personnel to face a risk of exposure to cytotoxic agents. Furthermore, peritonectomies and electro-evaporation of tumor nodules are performed with high voltage electrocautery, generating a large amount of surgical smoke during several hours. Inhalation of these fumes may be also a risk for healthcare workers. In this article, we analyse in depth these new risks of the operating room personnel, we review the literature, and we give guidelines for secure performance of cytoreductive surgery and hyperthermic intraoperative intraperitoneal chemotherapy, as well as for early postoperative intraperitoneal chemotherapy administration. These new procedures are safe techniques for patients and healthcare workers provided adequate policies are adopted to avoid occupational exposure. 相似文献
997.
Poor results after surgery for bronchioloalveolar carcinoma. 总被引:2,自引:0,他引:2
R A M Damhuis P R Schütte O C M Varin P M van den Berg R Heinhuis P W Plaisier 《European journal of surgical oncology》2006,32(5):573-576
BACKGROUND: Bronchioloalveolar carcinoma (BAC) is suggested to be less aggressive than other types of lung cancer. To assess the option of treatment modification, actual outcome data were studied and compared with results for other types of lung cancer. METHOD: Retrospective analysis of all consecutive patients who underwent resection for stage I lung cancer in our hospital. For 18 BAC cases, histological specimens were re-evaluated and in three cases diagnosis was revised. RESULTS: In the period 1989 through 2000, 15 patients with BAC and 260 patients with other tumour types underwent surgery in our hospital. Five-year survival rates were 24 and 53%, respectively, (p = 0.01). CONCLUSIONS: Given the poor results after standard surgery, parenchyma-sparing operations do not seem justified in patients with invasive BAC. 相似文献
998.
999.
Dr. R. Hinrichs L. Weber K. Scharffetter-Kochanek 《Der Hautarzt; Zeitschrift für Dermatologie, Venerologie, und verwandte Gebiete》2006,57(5):455-458
Ohne Zusammenfassung 相似文献
1000.