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   209930篇
  免费   29160篇
  国内免费   7098篇
耳鼻咽喉   1985篇
儿科学   1739篇
妇产科学   5240篇
基础医学   16412篇
口腔科学   2197篇
临床医学   17074篇
内科学   19737篇
皮肤病学   1421篇
神经病学   1011篇
特种医学   6176篇
外国民族医学   268篇
外科学   29700篇
综合类   27712篇
现状与发展   38篇
一般理论   3篇
预防医学   9942篇
眼科学   305篇
药学   14686篇
  139篇
中国医学   5029篇
肿瘤学   85374篇
  2024年   245篇
  2023年   4333篇
  2022年   6197篇
  2021年   11368篇
  2020年   10873篇
  2019年   9826篇
  2018年   9401篇
  2017年   9892篇
  2016年   10647篇
  2015年   12190篇
  2014年   17570篇
  2013年   17288篇
  2012年   13925篇
  2011年   14102篇
  2010年   10240篇
  2009年   10407篇
  2008年   10687篇
  2007年   10005篇
  2006年   8839篇
  2005年   7205篇
  2004年   6015篇
  2003年   5004篇
  2002年   4242篇
  2001年   3892篇
  2000年   3251篇
  1999年   2753篇
  1998年   2325篇
  1997年   2040篇
  1996年   1468篇
  1995年   1565篇
  1994年   1284篇
  1993年   1012篇
  1992年   874篇
  1991年   806篇
  1990年   602篇
  1989年   555篇
  1988年   458篇
  1987年   404篇
  1986年   336篇
  1985年   418篇
  1984年   329篇
  1983年   218篇
  1982年   232篇
  1981年   223篇
  1980年   191篇
  1979年   126篇
  1978年   93篇
  1977年   86篇
  1976年   60篇
  1975年   43篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
目的 调查乳腺癌患者伴发的抑郁焦虑与中医证型的关系.方法 对248例乳腺癌患者采用抑郁自评量表(SDS)及焦虑自评量表(SAS)评估,对其中符合抑郁焦虑诊断的157例患者进行中医辨证分型,研究不同年龄阶段、不同病程、不同疾病分期患者的中医证型特点.结果乳腺癌患者中伴有抑郁焦虑情绪占63.31%,其中抑郁患者以肝郁痰凝型最高(占46.94)%,焦虑患者以正虚毒炽型最高(占42.86%);不同年龄、不同病程、不同分期的患者伴发抑郁焦虑的证型构成比差异有统计学意义(P<0.01).结论 乳腺癌患者存在较高的抑郁焦虑情绪,肝郁痰凝型和正虚毒炽型与抑郁焦虑发生关系密切.  相似文献   
993.
OBJECTIVE: Circumferential resection margin (CRM) involvement has been correlated with a high risk of developing local recurrence. The aim of this study was to examine the prognostic significance of the CRM involvement after curative resection of rectal cancer in patients treated with preoperative radiotherapy and postoperative chemotherapy where indicated. METHOD: All patients with rectal cancer treated in a regional central unit from 1996 to 2004 were identified. A surgical resection was performed on 257 patients, and in 229 of these this was assessed as potentially curative. The CRM was examined in all patients. A CRM of < or = 1 mm was considered positive. RESULTS: A positive margin was seen in 19 (8%) patients. At a median follow up of 40 months, only four (1.7%) patients had developed local recurrence, one of whom had a positive CRM. In the four patients the tumour was 5 cm or less from the anal verge. There were no significant differences regarding local recurrence and survival between CRM positive and negative tumours. CONCLUSION: Rectal cancer managed by combined radiochemotherapy and surgery resulted in a low positive CRM rate and a low local recurrence rate. An involved CRM was not a predictor of local recurrence.  相似文献   
994.

Background

Motherwort has been used as medicinal herb for many years in both China and Europe. In particular, Chinese motherwort has been commonly used to treat disorders of mammary gland in Chinese traditional medicine (TCM). Chinese motherwort aqueous extract (MAE) was previously reported to have anti-cancer activity in breast cancer cells with low potency (IC50s in a range of 8–40 mg/mL). However, treatment of motherwort ethanol extract in vivo markedly suppressed the development of uterine adenomyosis and mammary cancers in mice. Therefore, anti-cancer activity of Chinese motherwort, especially in a form of ethanol extract, needs to be confirmed further at cellular level.

Materials and methods

Aerial part of Chinese motherwort (Leonurus japonicus Houtt) dry powder is extracted with 70% ethanol and the chemical components were characterized with HPLC finger print as well as mass spectrometry. Cytotoxicity of the motherwort aqueous ethanol extract (MAEE) was analyzed with MTT assay on ER negative MDA-MB-231 and ER positive MCF-7 human breast cancer cell lines. Hoechst 33342 staining and flow cytometry were used to verify whether the cell death induced by MAEE is apoptosis in nature. Cell cycle status of MAEE treated cells were analyzed with flow cytometry.

Results

Our results showed that MAEE caused cell death in a dose-dependent and time-dependent fashion in both ER positive and negative breast cancer cells. Morphology, Hoechst 33342 staining and flow cytometry evidence all indicated the cell death is not in an apoptotic nature. Furthermore, low concentrations of MAEE caused cell cycle arrest at G2/M phase.

Conclusions

These data suggest that Chinese motherwort aqueous ethanol extract may effectively inhibit the proliferation of breast cancer cells through mechanisms of both cytotoxicity and cell cycle arrest. The cellular effects of MAEE are non-apoptotic and ER independent on breast cancer cells.  相似文献   
995.
大肠癌肝转移射频消融后局部复发影响因素的分析   总被引:1,自引:0,他引:1  
目的 探讨射频消融(radiofrequency ablation,RFA)治疗大肠癌肝转移后局部肿瘤复发的风险因素。方法 回顾性研究213例347个肿瘤实施RFA治疗后局部复发的临床资料,对可能影响RFA局部治疗效果的临床因素进行统计学处理。结果 175例(82.2%)298个肿瘤(85.9%)得到CT或MRI随访资料。大肠癌肝转移灶RFA后肿瘤局部复发率为36.9%(110/298),局部复发的平均时间为16.4月(2~57个月)。单因素分析显示肝脏转移灶的部位、大小和射频针类型与肿瘤射频后的局部复发相关(P值分别为P=0.000,P=0.021和P=0.026),但Cox多因素分析则显示只有瘤大小和转移灶部位是大肠癌肝转移射频消融后局部复发的独立预后因素(χ^2=8.522,P=0.000;χ^2=1.321,P=0.022)。结论 肝脏肿瘤的大小和部位是RFA治疗效果的独立影响因素,正确的电极选择和布针是获得肿瘤完全坏死的关键。  相似文献   
996.
芳香化酶与乳腺癌的相关研究   总被引:1,自引:1,他引:0  
雌激素在乳腺癌的发生发展中起着重要作用。绝经后妇女的雌激素主要由肾上腺分泌的雄激素前体转化而来,芳香化酶是这一转变过程的关键酶、限速酶。因此,深入研究芳香化酶和乳腺癌的关系具有重要的临床意义。现就芳香化酶在乳腺癌组织中的表达、调控及芳香化酶抑制剂在乳腺癌内分泌治疗中的临床进展作一综述。  相似文献   
997.
Background Exploratory laparoscopy is commonly undertaken in patients with highly suspicious biliary and pancreatic lesions to facilitate diagnosis and staging cancer is present. If an unresectable tumor is identified, a second endoscopic procedure may be required do deploy a self-expandable metal stent (SEMS) for palliation. As endoscopic retrograde cholangio pancreatography (ERCP) may be unsuccessful in up to 20% of patients, we evaluated the feasibility and safety of deployment of self-expandable metal stents at the same time as the initial laparoscopy. Patients and Methods A total of 23 eligible patients (8 male and 15 female) with malignant obstruction of the common bile duct underwent deployment of SEMS at laparoscopy. Primary outcome measure was the successful laparoscopic deployment of stent and secondary outcome measure was complications rates. Results Indications for stent deployment were unresectable pancreatic cancer in 18, cholangiocarcinoma in two, neuroendocrine tumor in one and ampullary adenocarcinoma in two patients. The median age was 73 years (range 49–93). Twenty-two of 23 stents were deployed successfully: 17 stents were deployed transcystically and five via a choledochotomy. Median times for laparoscopic exploration and SEMS deployment were 165 min (range 105–230) and 20 min (range 10–50), respectively. Pre- and post-procedures median total bilirubin were 9.4 mg/dl (range 5.4–17.5) and 4.0 (range 2.6–7.1). The median size of the pancreatic mass was 3 cm (range 2–5 cm) and that of the common bile duct (CBD) from 9.2 mm (range 7.2–17.4). The mean duration of laparoscopy was 170 min (range 120–230 min) and that for stent deployment 23 min (range 10–50 min). Complications included bleeding, obstruction, and wound infection. Bleeding occurred on day 7 in two patients and on day 30 in one patient; bleeding occurred at the gastrojejunal anastomosis site and was successfully treated with endoscopic hemostasis. A total of three stent obstructions were identified: one each at 60, 90, and 120 days follow-up. All complications were successfully managed endoscopically. There were a total of seven deaths, six as a result of progressive cancer and one of surgical wound infection and ensuing complications. Conclusion This study demonstrates that laparoscopic deployment of self-expandable metal bile duct stents is feasible and safe. This option appears to be a reasonable option in patients with inoperable malignant obstruction of the distal common bile duct.  相似文献   
998.
Clinical diagnosis of chronic cholecystitis is made based on diffuse hyperechoic thickening of the gallbladder wall as shown by ultrasonographic examination. We herein report three cases of chronic cholecystitis showing localized hypoechoic thickening of the gallbladder wall that mimicked gallbladder cancer by ultrasonography. Histologically, hypertrophy of the muscularis propria was a common characteristic finding in these three patients. A smooth surface of the inner hypoechoic layer of the thickened wall was considered to be a reliable finding in the differential diagnosis between this type of chronic cholecystitis and gallbladder cancer.  相似文献   
999.
胃癌术后胆囊结石形成的研究进展   总被引:1,自引:0,他引:1  
胃癌是消化道的常见肿瘤,手术切除仍是其主要治疗手段。胃癌术后除了常见的并发症外,患者胆囊结石的发病率明显升高,部分需要二次手术,其结石原因涉及神经、体液等多方面因素,本文就胃癌手术对胆囊结石形成的研究进展作一综述。  相似文献   
1000.
This paper reviews the literature on colorectal cancer from a sex and gender-based perspective. Colorectal cancer is a major cause of death in the developed world, with rates increasing in developing countries. Although described by some writers as an ‘equal opportunity’ disease, it presents more risk to men than women. Both biological, or sex-linked factors, and gender-linked factors play a part in the aetiology of the disease, while gender differences in the use of screening and treatment also help shape the mortality gap between women and men for this condition. Without an appreciation of the part played by sex and gender in the risk of colorectal cancer, and without a gender-sensitive approach to screening in particular, it is possible that the mortality gap between men and women for this condition will widen in the future.  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