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   33923篇
  免费   2370篇
  国内免费   1148篇
耳鼻咽喉   359篇
儿科学   442篇
妇产科学   375篇
基础医学   5203篇
口腔科学   515篇
临床医学   3574篇
内科学   5564篇
皮肤病学   826篇
神经病学   2404篇
特种医学   1697篇
外国民族医学   5篇
外科学   3835篇
综合类   2546篇
现状与发展   7篇
一般理论   9篇
预防医学   1868篇
眼科学   871篇
药学   3532篇
  15篇
中国医学   1067篇
肿瘤学   2727篇
  2024年   60篇
  2023年   412篇
  2022年   1093篇
  2021年   1508篇
  2020年   865篇
  2019年   949篇
  2018年   1080篇
  2017年   861篇
  2016年   1096篇
  2015年   1539篇
  2014年   1850篇
  2013年   2034篇
  2012年   2858篇
  2011年   2952篇
  2010年   1739篇
  2009年   1462篇
  2008年   2004篇
  2007年   1955篇
  2006年   1709篇
  2005年   1603篇
  2004年   1252篇
  2003年   1064篇
  2002年   886篇
  2001年   714篇
  2000年   741篇
  1999年   593篇
  1998年   302篇
  1997年   252篇
  1996年   198篇
  1995年   185篇
  1994年   162篇
  1993年   121篇
  1992年   171篇
  1991年   181篇
  1990年   153篇
  1989年   124篇
  1988年   112篇
  1987年   91篇
  1986年   75篇
  1985年   56篇
  1984年   37篇
  1983年   40篇
  1982年   35篇
  1981年   28篇
  1980年   28篇
  1979年   31篇
  1978年   21篇
  1977年   20篇
  1976年   18篇
  1974年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
BACKGROUND CONTEXT: Intraoperative somatosensory evoked potential (SSEP) monitoring has been shown to reduce the incidence of new postoperative neurological deficits in scoliosis surgery. However, its usefulness during cervical spine surgery remains a subject of debate. PURPOSE: To determine the utility of intraoperative SSEP monitoring in a specific patient population (those with cervical radiculopathy in the absence of myelopathy) who underwent anterior cervical discectomy and fusion (ACDF) surgery. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: A total of 1,039 nonmyelopathic patients who underwent single or multilevel ACDF surgery. The control group (462 patients) did not have intraoperative SSEP monitoring, whereas the monitored group (577 patients) had continuous intraoperative SSEP monitoring performed. OUTCOME MEASURE: A new postoperative neurological deficit. METHODS: SSEP tracings were reviewed for all 577 patients in the monitored group and all significant signal changes were noted. Medical records were reviewed for all 1,039 patients to determine if any new neurological deficits developed in the immediate postoperative period. RESULTS: None of the patients in the control group had any new postoperative neurological deficits. In the monitored group there were six instances of transient SSEP changes (1 due to suspected carotid artery compression; 5 thought to be due to transient hypotension) which resolved with the appropriate intraoperative intervention (repositioning of retractors; raising the arterial blood pressure). Upon waking up from anesthesia, one patient in the monitored group had a new neurological deficit (partial central cord syndrome) despite normal intraoperative SSEP signals. CONCLUSIONS: ACDF appears to be a safe surgical procedure with a low incidence of iatrogenic neurological injury. Transient SSEP signal changes, which improved with intraoperative interventions, were not associated with new postoperative neurological deficits. An intraoperative neurological deficit is possible despite normal SSEP signals.  相似文献   
12.
Pituitary abscess is a rare and potentially lethal condition. Pituitary abscess in a pregnant woman has not been previously described. A 38-year-old pregnant woman (34 weeks gestation) with a pituitary mass complained of a progressive headache and sudden visual impairment. She was afebrile and had no inflammatory symptoms on admission. On MRI, the preoperative diagnosis was pituitary adenoma with sphenoid sinusitis. She underwent an uncomplicated transsphenoidal procedure for removal of the pituitary mass. The next day, labor commenced and a healthy preterm baby was delivered. Pathologic examination of the intrasellar mass showed polymorphonuclear cells, debris and no tumor cells. The sellar contents were cultured and Streptococcus viridans was grown. To our knowledge this is the first case of pituitary abscess reported during pregnancy. Although the patient was pregnant, the transsphenoidal approach was safe for the mother and the fetus. Surgical drainage and antibiotic therapy are required for the definitive treatment of this condition.  相似文献   
13.
眼球挫伤与锌   总被引:2,自引:2,他引:0  
从1991年11月到1992年8月对50例眼挫伤的血清锌进行测定,36例异常占72%,其中有眼底改变占75%。视神经视网膜挫伤锌值增高。低锌影响杆细胞及锥细胞代谢致视力低下,低锌影响视色素合成及色素上皮代谢,造成伤后视网膜色紊乱。  相似文献   
14.
石刻雕塑作业劳动卫生学调查及实验研究   总被引:1,自引:0,他引:1  
测定了石雕作业粉尘浓度,几何平均浓度为82.35~3.67mg/m3。工人职业性健康检查结果,接尘工人的咽部充血、咳嗽、咯痰检出率高于对照组;肺功能低下的检出率也高于对照组。该厂自1972年以来发生尘肺患者17例,其病情发展和晋期缓慢,发病工龄长。动物实验研究表明,石雕粉尘有轻微的致纤维化作用。  相似文献   
15.
BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most prevalent fatal cancers in the world. Despite advances in early diagnosis and improvements in surgical techniques, the survival of patients with HCC even after resection is poor because of the high incidence of recurrences. Therefore, the identification of prognostic factors may be helpful in the development of new treatment protocols. AIMS: To investigate HER-2/neu status in HCC by immunohistochemistry (IHC) and fluorescence in situ hybridisation (FISH), and to explore the possibility of using trastuzumab in the treatment of HCC. METH ODS: Eight hundred and sixty eight surgical samples from patients with primary HCC were examined for their HER-2/neu status. IHC for HER-2/neu was performed with the HercepTest kit; FISH analysis was performed with the PathVysion HER-2 DNA probe kit. The correlations between HER-2/neu overexpression and clinicopathological characteristics were analysed statistically. RESULTS: HER-2/neu overexpression was detected in 21 (2.42%) of the 868 primary HCCs. Only one specimen showed HER-2/neu gene amplification by FISH. No significant associations were found between HER-2/neu overexpression and the clinicopathological parameters. CONCLUSIONS: There is a low frequency of HER-2/neu overexpression/amplification in HCC. There appears to be no role for HER-2/neu as a prognostic marker and no benefit of anti-HER-2/neu trastuzumab treatment in patients with HCC.  相似文献   
16.
目的评价经皮椎体成形术治疗脊柱疾病的临床应用价值.方法 56例多发骨髓瘤、溶骨性脊柱转移瘤、骨质疏松性椎体压缩性骨折患者应用经皮椎体成形术后,分24 h、3个月两阶段评估患者疼痛、术后X线片检查结果、椎体高度等指标.结果术后止痛效果良好,尤以骨质疏松性椎体压缩性骨折患者的止痛效果最好.无严重并发症. 结论经皮椎体成形术对骨质疏松性椎体压缩性骨折等脊柱疾病的止痛、稳固椎体等效果明显,可以谨慎开展.  相似文献   
17.
OBJECTIVE: To evaluate the usefulness of the TenElectrodes, a new stimulator for inching test, in the diagnosis and localization of ulnar neuropathy at the elbow (UNE). METHODS: Sixty-two ulnar nerves in 40 control subjects and 24 ulnar nerves in 23 patients with typical symptoms and signs of UNE were studied. The inching test of ulnar motor nerve using TenElectrodes was done along 8 cm across the elbow in the extended position. RESULTS: In the inching test of the control group, the mean segmental latency difference was 0.19+/-0.08 ms. Maximal latency difference over a 1 cm segment did not exceed 0.40 ms in any of the controls but exceeded 0.5 ms or more in all clinical UNE patients. In all UNE patients, the lesion sites were identified by the inching test using TenElectrodes: the retroepicondylar groove (54.2%), the humeroulnar arcade (29.2%), and dual compression (16.6%). CONCLUSIONS: TenElectrodes is a useful stimulator for the inching test in the diagnosis of UNE. The precise localization of compression was possible in all patients with UNE and the most common site was the retroepicondylar groove.  相似文献   
18.
Background: The fabrication of dental prosthesis requires the transfer of interocclusal records from patient's mouth to semiadjustable articulators using different kinds of recording media. Any inaccuracy in these interocclusal records leads to occlusal errors in the final prosthesis. This study was conducted to evaluate the dimensional changes occurring in the interocclusal recording material over a given period of time and the material's resistance to compression during the cast mounting on the articulator.  相似文献   
19.
20.
Osteogenesis is synergistically enhanced by the combined effect of complimentary factors. This study showed that Nell-1 and BMP-2 synergistically enhanced osteogenic differentiation of myoblasts and phosphorylated the JNK MAPK pathway. The findings are important because of the osteochondral specificity of Nell-1 signaling and the potential therapeutic effects of coordinated BMP-2 and Nell-1 delivery. INTRODUCTION: BMPs play an important role in the migration and proliferation of mesenchymal cells and have a unique ability to alter the differentiation of mesenchymal cells toward chondrogenic and osteogenic lineages. Signaling upstream of Cbfa1/Runx2, BMPs effects are not limited to cells of the osteoblast lineage. Thus, additional osteoblast-specific factors that could synergize with BMP-2 would be advantageous for bone regeneration procedures. NELL-1 (NEL-like molecule-1; NEL [a protein strongly expressed in neural tissue encoding epidermal growth factor like domain]) is a novel growth factor believed to preferentially target cells committed to the osteochondral lineage. MATERIALS AND METHODS: C2C12 myoblasts were transduced with AdLacZ, AdNell-1, AdBMP-2, or AdNell-1+AdBMP-2 overexpression viruses. Effects were studied by cell morphology, alkaline phosphatase activity, osteopontin production, and MAPK signaling. Additionally, in a nude mouse model, viruses were injected into leg muscles, and new bone formation was examined after 2 and 8 wk. RESULTS: C2C12 myoblasts co-transduced with AdNell-1+AdBMP-2 showed a synergistic effect on osteogenic differentiation as detected by alkaline phosphatase activity and osteopontin production. Nell-1 stimulation on AdNell-1 + AdBMP-2 preconditioned C2C12 cells revealed significant activation of the non-BMP-2 associated c-Jun N-terminal kinase (JNK) MAPK signaling pathway, but not the p38 or extracellular signal-regulated kinase (ERK1/2) MAPK pathways. Importantly Nell-1 alone did not induce osteogenic differentiation of myoblasts. In a nude mouse model, injection of AdNell-1 alone stimulated no bone formation within muscle; however, injection of AdNell-1+AdBMP-2 stimulated a synergistic increase in bone formation compared with AdBMP-2 alone. CONCLUSIONS: These findings are important because of the confirmed osteochondral specificity of Nell-1 signaling and the potential therapeutic effects of enhanced BMP-2 action with coordinated Nell-1 delivery.  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