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   37164篇
  免费   2137篇
  国内免费   201篇
耳鼻咽喉   425篇
儿科学   1156篇
妇产科学   997篇
基础医学   3700篇
口腔科学   1212篇
临床医学   3257篇
内科学   8020篇
皮肤病学   671篇
神经病学   2211篇
特种医学   1318篇
外国民族医学   4篇
外科学   6778篇
综合类   869篇
现状与发展   3篇
一般理论   27篇
预防医学   2500篇
眼科学   1355篇
药学   2859篇
  1篇
中国医学   266篇
肿瘤学   1873篇
  2024年   39篇
  2023年   413篇
  2022年   1051篇
  2021年   1648篇
  2020年   985篇
  2019年   1255篇
  2018年   1566篇
  2017年   1137篇
  2016年   1232篇
  2015年   1332篇
  2014年   1681篇
  2013年   2051篇
  2012年   3095篇
  2011年   2993篇
  2010年   1692篇
  2009年   1462篇
  2008年   2225篇
  2007年   2294篇
  2006年   2024篇
  2005年   1790篇
  2004年   1624篇
  2003年   1351篇
  2002年   1177篇
  2001年   367篇
  2000年   306篇
  1999年   282篇
  1998年   205篇
  1997年   139篇
  1996年   149篇
  1995年   109篇
  1994年   102篇
  1993年   80篇
  1992年   148篇
  1991年   161篇
  1990年   128篇
  1989年   125篇
  1988年   106篇
  1987年   97篇
  1986年   88篇
  1985年   118篇
  1984年   77篇
  1983年   52篇
  1982年   53篇
  1981年   55篇
  1980年   41篇
  1979年   50篇
  1978年   40篇
  1975年   36篇
  1974年   36篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
A breast mass caused by foreign body type granulomatous reaction to surgical material is a very rare lesion and may mimic carcinoma. Reported foreign materials have included suture materials, silicone, paraffin, gunpowder and carbon particles used for localization of a nonpalpable breast lesions. To our knowledge, a foreign body reaction to gauze sponge has not been reported previously. A 58-year-old woman who had an enlarging mass that mimicked breast carcinoma, due to foreign body reaction to gauze sponge is presented here, and relevant literature is reviewed.  相似文献   
994.
The use of gamma-radiation in treatment of pelvic cancer is associated with injury of healthy surrounding tissues and disorders of intestinal motility; however, the cellular mechanisms involved are unclear. We tested the hypothesis that exposure of visceral smooth muscle cells (SMCs) to gamma-radiation induces apoptosis via activation of specific protein kinase C (PKC) isoforms. Cultured SMCs and slices from guinea pig ileum smooth muscle longitudinal layer (GPISMLL) were exposed to 10 to 50 Gy. Flow cytometry in gamma-radiated SMCs showed increased percentage of cells in the sub-G(0)/G(1) phase, a hallmark of apoptosis. gamma-Radiation-induced reduction in cell survival was partially but significantly alleviated with the PKC inhibitors. Sections of gamma-irradiated GPISMLL showed DNA fragmentation and apoptotic bodies analyzed by the terminal deoxynucleotidyl transferase dUTP nick-end labeling method, whereas the plasma and nuclear membranes were preserved. Confocal microscopy in gamma-radiated SMCs labeled with annexin V-fluorescein showed an increase in apoptotic cells and phosphatidylserine externalization. Contraction of GPISMLL strips in response to KCl and acetylcholine was reduced in tissues exposed to 30 and 50 Gy. gamma-Radiation of GPISMLL caused an increase in PKC activity in the particulate fraction, a decrease in the cytosolic fraction, and increased particulate/cytosolic PKC activity ratio. Western blot analysis revealed significant amounts of alpha- and epsilon-PKC in the cytosolic fraction of control GPISMLL. gamma-Radiation caused an increase in the amount of alpha- and epsilon-PKC in the particulate fraction and a decrease in the cytosolic fraction. Data suggest that gamma-radiation induces apoptosis, growth arrest, and contractile dysfunction in visceral SMCs of GPISMLL via activation and translocation of alpha- and epsilon-PKC isoforms.  相似文献   
995.
Gastrocutaneous fistula after gastrostomy tube removal may persist for a prolonged period. We present a case of a 58-year-old woman with a GCF that had persisted for 5 months following the removal of an endoscopically-placed gastrostomy tube (PEG). Conservative therapy with anti-acid medications and administering motility agents was unsuccessful. For the closure of the GCF, the endoscopic metal clips were used to close the fistula.  相似文献   
996.
997.
AIM: The aim of this article is to report a case of bilateral multiple impacted supernumerary teeth. A discussion of possible mechanisms of development is also presented along with a concise review of the literature. BACKGROUND: Supernumerary teeth occur in the context of various scenarios in the primary and the permanent dentition. Multiple supernumerary teeth are a rare finding especially in the absence of associated syndrome or disease. REPORT: A case of bilateral multiple impacted supernumerary teeth localized to the mandibular premolar region is reported. Some of the supernumerary teeth as well as the erupted premolars had persistent open apices. Coronal malformation of the right maxillary first premolar was another interesting finding. There was an absence of any concomitant disease. SUMMARY: The aforementioned combination of findings has not been reported previously. The anatomical, geometrical, and spatial relationships of supernumerary teeth with their erupted equivalents may shed light on some controversial aspects of the etiology.  相似文献   
998.
999.
PURPOSE: To evaluate the influence of thermal and mechanical load cycling on the microtensile dentin bond strength of two self-etching and one total-etch adhesives. METHODS: The adhesive materials were: a two-step self-etch adhesive (Clearfil SE Bond), a one-step self-etch adhesive (Hybrid Bond), and a total-etch one-step adhesive (Admira Bond). Sixty freshly extracted human third molars were used. In each tooth, a Class I cavity (4 x 4 mm) was prepared in the occlusal surface with the pulpal floor extending about 1 mm into dentin. The teeth were divided into three groups (n=20). Each group was restored with the resin composite Clearfil APX using one of the adhesives. After restoration, 10 teeth in each group were thermocycled between 5 degrees C and 55 degrees C, (dwell time 3 minutes, 5,000 cycles). The same teeth were then mounted in a fatigue loading machine to receive an intermittent load of 125 N at 52 cycles/minute for 4,000 cycles. Subsequently, each tooth was sectioned longitudinally, bucco-lingually and mesio-distally to get rectangular slabs 1-1.2 mm in thickness for the microtensile test. Each slab was then placed in a universal testing machine and tensile load was applied at a cross-head speed of 0.05 mm/minute. RESULTS: Without loading procedures, there was no significant difference in the bond strength of the tested adhesives. In contrast to Admira Bond and Clearfil SE Bond, fatigue loading resulted in a significant reduction of the bond strength for Hybrid Bond when compared to the unloaded restorations.  相似文献   
1000.
In LeFort I surgery, the separation of the pterygomaxillary junction is done by osteotomy. Although the osteotome is positioned too close to the maxillary artery and its branches during pterygomaxillary separation, postoperative complications from vascular injuries are uncommon. We describe an unusual occurrence of a maxillary artery pseudoaneurysm after LeFort I and bilateral sagittal split osteotomies for maxillary advancement and mandibular setback as well as (anterior sliding) genioplasty. In a patient with class III occlusion and midface retrusion, the significant bleeding began 10 days postoperatively, which was controlled by anterior and posterior nasal packing. The bleeding recurred 28 days after surgery; thus, vascular anatomy in the pterygomaxillary area is reviewed, pseudoaneurysm was diagnosed on selective carotid angiography and successfully treated by embolization; and 2-year follow up was uneventful.  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