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   2472848篇
  免费   176061篇
  国内免费   3638篇
耳鼻咽喉   33640篇
儿科学   79077篇
妇产科学   65808篇
基础医学   365937篇
口腔科学   68164篇
临床医学   218675篇
内科学   483308篇
皮肤病学   55113篇
神经病学   195342篇
特种医学   90834篇
外国民族医学   490篇
外科学   367083篇
综合类   48075篇
现状与发展   12篇
一般理论   869篇
预防医学   198365篇
眼科学   57743篇
药学   184914篇
  11篇
中国医学   5032篇
肿瘤学   134055篇
  2021年   20941篇
  2019年   21793篇
  2018年   30939篇
  2017年   22819篇
  2016年   25147篇
  2015年   28310篇
  2014年   39065篇
  2013年   58490篇
  2012年   82896篇
  2011年   88118篇
  2010年   51244篇
  2009年   47542篇
  2008年   81472篇
  2007年   86915篇
  2006年   87385篇
  2005年   84482篇
  2004年   80626篇
  2003年   77379篇
  2002年   74792篇
  2001年   111252篇
  2000年   114254篇
  1999年   95640篇
  1998年   27428篇
  1997年   23931篇
  1996年   24320篇
  1995年   22952篇
  1994年   21096篇
  1993年   19878篇
  1992年   73215篇
  1991年   71218篇
  1990年   69567篇
  1989年   66717篇
  1988年   61342篇
  1987年   60089篇
  1986年   56221篇
  1985年   53938篇
  1984年   40018篇
  1983年   34005篇
  1982年   20189篇
  1979年   36779篇
  1978年   26252篇
  1977年   21801篇
  1976年   20905篇
  1975年   22476篇
  1974年   26992篇
  1973年   25707篇
  1972年   24059篇
  1971年   22883篇
  1970年   21050篇
  1969年   20169篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
OBJECTIVE: To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life. METHODS: This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers. RESULTS: In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted. CONCLUSIONS: RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations.  相似文献   
153.
154.
155.
Vacuum-assisted closure (VAC), although a modern adjunct in wound management, has not been used previously in pyoderma gangrenosum (PG), probably to avoid the potential complications of ‘pathergy’. We would like to report our experience of VAC in three cases of PG with the relevant review of literature.  相似文献   
156.
157.
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   
158.
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   
159.
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   
160.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  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