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   28847篇
  免费   1707篇
  国内免费   700篇
耳鼻咽喉   631篇
儿科学   591篇
妇产科学   624篇
基础医学   5435篇
口腔科学   546篇
临床医学   3680篇
内科学   3984篇
皮肤病学   382篇
神经病学   842篇
特种医学   721篇
外国民族医学   12篇
外科学   1860篇
综合类   4429篇
现状与发展   1篇
预防医学   2886篇
眼科学   359篇
药学   1595篇
  12篇
中国医学   625篇
肿瘤学   2039篇
  2024年   99篇
  2023年   229篇
  2022年   614篇
  2021年   796篇
  2020年   789篇
  2019年   707篇
  2018年   755篇
  2017年   736篇
  2016年   847篇
  2015年   916篇
  2014年   1757篇
  2013年   1701篇
  2012年   1695篇
  2011年   1999篇
  2010年   1531篇
  2009年   1530篇
  2008年   1457篇
  2007年   1592篇
  2006年   1432篇
  2005年   1377篇
  2004年   1170篇
  2003年   1091篇
  2002年   940篇
  2001年   844篇
  2000年   751篇
  1999年   613篇
  1998年   563篇
  1997年   494篇
  1996年   425篇
  1995年   421篇
  1994年   365篇
  1993年   230篇
  1992年   162篇
  1991年   133篇
  1990年   79篇
  1989年   67篇
  1988年   45篇
  1987年   37篇
  1986年   32篇
  1985年   53篇
  1984年   29篇
  1983年   25篇
  1982年   35篇
  1981年   12篇
  1980年   19篇
  1979年   16篇
  1978年   16篇
  1977年   5篇
  1976年   8篇
  1973年   6篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
We report herein the case of a 70-year-old man in whom a chest wall implantation of adenocarcinoma of the lung at the drainage tube site was found 4 months after a right lower lobectomy with mediastinal lymph node dissection had been performed for adenocarcinoma of the right lower lobe. The lesion was successfully treated by tumor extirpation. We believe that tumor seeding to the chest wall occurred at the time of thoracotomy. To prevent such tumor seeding, the pleural cavity should be washed out routinely with a massive volume of physiological saline solution prior to closure of the chest wall.  相似文献   
22.
目的:寻找适合于临床PCR检测结核杆菌DNA简单、快速、有效、经济的细菌裂解方法。方法:采用11种细菌裂解剂对相同数量的结核分枝杆菌进行裂解,裂解上清液直接用于PCR扩增,结果:1%TritonX-100,1%NP40,1%Teween20、和1%OP四种裂解剂的裂解液可直接扩增出结核分枝杆菌DNA;SDS,NaOH,十二烷基肌酸钠等裂解剂的裂解液直接用于PCR扩增均为阴性。结论:1%的Tritonx-100,NP40、Teween20和乳化剂OP裂解细菌效果好,又不抑制PCR反应,适合于作为临床PCR检测结核杆菌的裂解剂。  相似文献   
23.
空管药物疗法治疗牙髓病和根尖周病疗效观察   总被引:1,自引:0,他引:1  
用SMTD复合药物对牙髓病和根尖周病实施空管药物疗法。78例103颗获得完整随访资料患牙经两年观察,92.2%治愈率。文章介绍了治疗方法,讨论了空管药物疗法的愈合机理、优点、失败原因及其预防措施。  相似文献   
24.
25.
胆道支撑管显影材料的制备及体外细胞毒性评价   总被引:4,自引:0,他引:4  
目的 探讨新型显影胆道支撑管材料制备的可行性,对构建出的材料进行体外细胞毒性评价和筛选。方法 选择具有X线下显影特性的基础材料A、B、C,分别与硅橡胶生胶共混炼,模压后分别得到相应的显影复合材料甲、乙、丙,经一段和二段硫化过程完成加工。采用MTT法作为体外细胞毒性评价的方法,测定参比对照材料和新材料的50%浓度的浸提液对小鼠成纤维细胞的增殖率的影响,确定细胞毒性级别。结果 新材料甲、乙、丙在x线下影像清晰。甲、乙材料的细胞毒性级别为零,丙材料细胞毒性级别为2。结论 构建出在X线下显影的弹性体材料可行。材料甲、乙是制造新型胆道支撑管的初选材料,材料丙无应用的价值。  相似文献   
26.
报道13例应用显徽外科技术进行输卵管绝育术后吻合术。全部病例至少随访1年。13例术后行输卵管通液术,提示输卵菅通畅(100%),13例中11例妊娠(84.62%),并复习文献,对影响手术成功的诸多因素进行讨论。  相似文献   
27.
An extensive review of the currently available literature on primary fallopian tube carcinoma is presented. The role of vaginal ultrasonography and the importance of an aggressive evaluation of every tubal deformity is stressed. A staging system which takes into account recent data on the biology of this malignancy is proposed. We emphasize the largely underestimated importance of early lymphatic spread of this disease, necessitating a thorough staging laparotomy with pelvic and para-aortic lymph node sampling in the apparent early stages. The need for adjuvant treatment is obvious, but until now no firm data exist as to what the optimal strategy should be. We recommend that until more representative studies are available, ovarian carcinoma protocols should be used in clinical practice.  相似文献   
28.
Recently developed PCR systems offer online-monitoring of amplification and allow simple and reliable DNA quantification. We have used the LightCycler system to develop a simple and rapid method for direct identification of female carriers of deletions and duplications in the dystrophin gene. The challenge resides in the ability to identify the presence of a deleted or duplicated allele over the background contributed by the normal allele. Quantification is based on the determination of the ratio between potentially deleted/duplicated dystrophin exons and non-deleted/-duplicated reference exons using the unspecific dsDNA-dye SYBRgreen I. In a retrospective study, we evaluated our method in female relatives of DMD/BMD patients with known carrier status by comparative analysis of deleted or duplicated versus non-deleted/-duplicated exons. Carrier status was accurately attributed in 100% of cases, the mean ratios being 0.52+/-0.12 for deletion carriers (expected value: 0.5) and 1.56+/-0.18 for duplication carriers (expected value: 1.5) vs. 1.022+/-0.17 for non-carriers (expected value: 1.0). The method proved to be simple, rapid, reliable, and cost-effective. It may be used for direct determination of deletions/duplications in potential DMD/BMD carriers and may easily be adapted for other genetic conditions involving deletions and duplications.  相似文献   
29.
Recurrent respiratory papillomatosis (RRP) is the most common benign tumour of the larynx, affecting both children and adults. We present a series of 25 patients, including 10 cases of juvenile multiple, 8 cases of adult solitary, and 7 cases of adult multiple RRP. Biopsy tissue from each patient was screened by Southern blot hybridization and polymerase chain reaction for the presence of human papillomavirus (HPV) DNA. Sera from patients and age- and sex-matched controls were tested for the presence of HPV-specific antibodies using a synthetic pep-tide derived from the minor capsid protein (L2) of HPV 6/11. By Southern blot hybridization and/or polymerase chain reaction, biopsies from all patients were positive for HPV 6/11 DNA. There was no difference in antibody response between cases and controls. Female cases and controls had significantly higher antibody titers than male subjects. A correlation was observed between the HPV-specific antibody level and the number of surgery-necessitating recurrences. © 1994 Wiiey-Liss, Inc.  相似文献   
30.
Oncogenesis is the consequence of a series of genetic alterations that allow unrestrained cellular growth, tissue invasion, and eventual metastases. Tumor-related genes can be classified into functional categories. Proto-oncogenes/oncogenes have a stimulatory role in cell growth, and the inactivation of cancer-suppressor genes/antioncogenes results in the loss of cell cycle regulation. More recently, three other groups of tumor-related genes have been recognized. They include the antiapoptosis genes which protect from programmed cell death, the antimetastasis genes, and multidrug resistance genes. Besides aiding in tumor diagnosis, the detection of such tumor-associated genes and their products allows the identification of individuals with an inherited predisposition to neoplastic growths, and the overexpression of many of these oncogene products has been shown to be a potential marker of tumor behavior and a predictor of treatment outcome and response. The ability to utilize DNA and RNA probes for nucleic acid hybridization and polymerase chain reaction procedures in cell and tissue preparations of solid tumors and lymphoid proliferations expands and complements the information provided by immunohistochemical techniques. These probes allow direct visualization and correlation of specific genes and their protein products with cytomorphologic features, and form a powerful addition to the armamentarium of the cytopathologist and surgical pathologist. © 1995 Wiley-Liss, Inc.  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