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   553483篇
  免费   297407篇
  国内免费   52807篇
耳鼻咽喉   5413篇
儿科学   8224篇
妇产科学   8658篇
基础医学   124340篇
口腔科学   7869篇
临床医学   98667篇
内科学   142480篇
皮肤病学   8062篇
神经病学   37921篇
特种医学   19100篇
外国民族医学   130篇
外科学   74993篇
综合类   95415篇
现状与发展   59篇
一般理论   64篇
预防医学   59694篇
眼科学   25026篇
药学   87652篇
  215篇
中国医学   59189篇
肿瘤学   40526篇
  2023年   6467篇
  2022年   14041篇
  2021年   17638篇
  2020年   16225篇
  2019年   22147篇
  2018年   23333篇
  2017年   22652篇
  2016年   20865篇
  2015年   25036篇
  2014年   28099篇
  2013年   27254篇
  2012年   34566篇
  2011年   38300篇
  2010年   31123篇
  2009年   35653篇
  2008年   27867篇
  2007年   24983篇
  2006年   24090篇
  2005年   24515篇
  2004年   21034篇
  2003年   19098篇
  2002年   18032篇
  2001年   18954篇
  2000年   14933篇
  1999年   20403篇
  1998年   18229篇
  1997年   18055篇
  1996年   18149篇
  1995年   18026篇
  1994年   17375篇
  1993年   15178篇
  1992年   15642篇
  1991年   14498篇
  1990年   13113篇
  1989年   12673篇
  1988年   12047篇
  1987年   11359篇
  1986年   10566篇
  1985年   9439篇
  1984年   7150篇
  1983年   7029篇
  1982年   7863篇
  1981年   7358篇
  1980年   7006篇
  1979年   6945篇
  1978年   5992篇
  1977年   6261篇
  1976年   5868篇
  1975年   5588篇
  1974年   5174篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
We describe a case of a large bronchial fistula and empyema after right upper lobectomy that was treated successfully with open window thoracostomy followed by a latissimus dorsi myocutaneous flap and limited thoracoplasty. A latissimus dorsi myocutaneous flap can provide immediate airtight closure of a large bronchial fistula, allowing lavage and curettage of the empyema cavity to reduce the chance of postoperative infection. An important aspect of this technique is that the deepithelialized skin side rather than muscle is sutured to an opening of the bronchus. As compared with other techniques, a latissimus dorsi myocutaneous flap is superior in that it requires a single incision and does not require an intraop-erative change of position. In addition, the technique causes little dysfunction of the chest and shoulder and preserves the vascular supply to ensure the viability of the flap even if it was divided in a previous operation.  相似文献   
993.
The current report focuses on two patients of the same age who presented similar appearances on initial anteroposterior chest images. Follow-up images showed superoanterior and superoposterior mediastinal lesions. The first patient with noninvasive cystic thymoma was suspected before surgery, while the pathologic diagnosis was intrathoracic phrenic nerve schwannoma. The second patient was with an asymmetric, dumbbell-shaped paravertebral tumor over T3 and T4 on the left side. The preoperative…  相似文献   
994.

Background  

Glioblastoma multiforme is the most malignant form of brain tumor. Despite treatment including surgical resection, adjuvant chemotherapy, and radiation, these tumors typically recur. The recurrent tumor is often resistant to further therapy with the same agent, suggesting that the surviving cells that repopulate the tumor mass have an intrinsic genetic advantage. We previously demonstrated that cells selected for resistance to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) are near-diploid, with over-representation of part or all of chromosomes 7 and 22. While cells from untreated gliomas often have over-representation of chromosome 7, chromosome 22 is typically under-represented.  相似文献   
995.
The beta-adrenoceptor (beta-AR)-stimulatory guanine nucleotide-binding (Gs) protein system has been shown to play important roles in the cardiovascular system. The gene encoding the alpha-subunit of Gs proteins (GNAS1) is a candidate genetic determinant for hypertension. Because alcohol consumption is known to affect blood pressure partly through the beta-AR-Gs protein system, we examined the possible interaction between GNAS1 T393C polymorphism and drinking status in the association with hypertension in the present study. As a result, a non-significant but reasonable trend supporting the presence of an interaction was shown (p = 0.076). In line with this trend, the T393C polymorphism significantly interacted with drinking status in the association with systolic blood pressure (p = 0.028). Moreover, supporting the presence of an interaction, T allele carriers consistently had a higher probability of hypertension, higher systolic blood pressure, and higher diastolic blood pressure than CC homozygotes in non-drinkers and light drinkers. In contrast, CC homozygotes consistently had a higher probability of hypertension, higher systolic blood pressure, and higher diastolic blood pressure than T allele carriers in moderate to heavy drinkers. The present study also showed a significant interaction between the T393C polymorphism and drinking status in the association with pulse pressure (p = 0.026), reflected by a significant association between the T393C polymorphism and pulse pressure in moderate to heavy drinkers (p = 0.026). These findings may be helpful in conducting further molecular and biological studies on the relationship among the effects of alcohol, the beta-AR-Gs protein system, and hypertension.  相似文献   
996.
997.
通过三年资料实证医院检验科常规项目全成本   总被引:2,自引:0,他引:2  
目的弄清医院常规检验项目的实际成本,为医院及卫生主管部门进行科学管理和政府物价部门制订科学合理的收费价格体系提供科学依据。方法对某二级甲等医院检验科3年中所开展的全部7大类16个项目组169个检验项目的成本按耗材、设备折旧、劳务费、房屋折旧、业务费与后勤管理费共5大类进行实证分析。结果该科的成本构成比是:耗材成本34.1%、设备折旧24.3%、劳务费30.0%、房屋折旧4.0%、业务费与后勤管理费7.6%;检验项目的每项次平均成本为7.17元;成本最低的两类检验项目是生化及定性免疫,其项次成本分别为3.18元和4.25元;最高的则为微生物和血库,项次成本分别为48.63元和35.21元;项次成本过百元的有7项,多为输血项目;5至10倍于平均成本的28项,2至5倍于全科平均成本的22项,其余112项介于全科平均成本上下。结论实证研究是准确掌握检验项目成本的有效方法。  相似文献   
998.
教学活动包括诸要素,其中一个常被人忽视的要素就是教学软环境。教学软环境的优劣在某种程度上决定着教学活动的成效。教师在教学活动中应设法构建良好的教学软环境,营造良好的课堂气氛,取得最佳的教学效果。  相似文献   
999.
1000.
Abstract Simultaneous bilateral avulsions of the tibial tuberosity are rare injuries. The authors found only five reported cases in the orthopedic literature. We add a further case of bilateral avulsions of the tibial tuberosity with the longest reported follow-up.  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