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   21544篇
  免费   2129篇
  国内免费   1180篇
耳鼻咽喉   155篇
儿科学   729篇
妇产科学   313篇
基础医学   2370篇
口腔科学   354篇
临床医学   2837篇
内科学   3134篇
皮肤病学   269篇
神经病学   1074篇
特种医学   904篇
外国民族医学   6篇
外科学   2672篇
综合类   3251篇
现状与发展   3篇
一般理论   3篇
预防医学   1700篇
眼科学   414篇
药学   2130篇
  18篇
中国医学   970篇
肿瘤学   1547篇
  2024年   76篇
  2023年   293篇
  2022年   708篇
  2021年   1011篇
  2020年   752篇
  2019年   657篇
  2018年   778篇
  2017年   700篇
  2016年   626篇
  2015年   919篇
  2014年   1103篇
  2013年   1043篇
  2012年   1493篇
  2011年   1539篇
  2010年   1108篇
  2009年   856篇
  2008年   1093篇
  2007年   1090篇
  2006年   1067篇
  2005年   952篇
  2004年   746篇
  2003年   691篇
  2002年   623篇
  2001年   548篇
  2000年   421篇
  1999年   380篇
  1998年   232篇
  1997年   234篇
  1996年   176篇
  1995年   138篇
  1994年   147篇
  1993年   123篇
  1992年   202篇
  1991年   181篇
  1990年   148篇
  1989年   152篇
  1988年   159篇
  1987年   126篇
  1986年   137篇
  1985年   136篇
  1984年   106篇
  1983年   74篇
  1982年   65篇
  1981年   76篇
  1979年   98篇
  1978年   59篇
  1977年   60篇
  1973年   73篇
  1972年   58篇
  1971年   62篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
Dorsal root ganglionectomy has been suggested as a method for the treatment of chronic intractable radicular pain, with theoretical advantages over dorsal rhizotomy, which does not interrupt ventral root afferents. The indications for these procedures in patients with persistent pain following lumbosacral spine surgery are not well established. Long-term results have been reported infrequently, and no published series has a mean follow-up period of more than 30 months. The authors have reviewed their experience with a series of 13 patients with failed back surgery syndrome, in whom dorsal root ganglionectomy was performed. Patients were selected on the basis of clinical presentation and diagnostic root blocks suggesting a monoradicular pain syndrome. Follow-up data were obtained at a mean of 5.5 years following dorsal root ganglionectomy. Follow-up interviews to assess outcome were conducted by a disinterested third party. Treatment "success" (at least 50% sustained relief of pain and patient satisfaction with the result) was recorded in two patients at 2 years after surgery and in none at 5.5 years. Equivocal success (at least 50% relief, without clearcut patient satisfaction) was recorded in one patient at 2 and at 5.5 years postoperatively. Improvements in activities of daily living were recorded in a minority of patients. Loss of sensory and motor function was reported frequently by patients. A minority of patients had reduced or eliminated analgesic intake. These results suggest that dorsal root ganglionectomy has a limited role in the management of failed back surgery syndrome, and that methods to select patients to receive this procedure should be refined or alternative approaches should be considered.  相似文献   
93.
94.
Viable management decisions, in health care just as in industry, must be based on many inputs--including financial valuation, which has not traditionally been applied in the health sector. Financial valuation helps to insure both continued service to the community and economic survival of the institution.  相似文献   
95.
96.
黄芪注射液临床应用进展   总被引:3,自引:0,他引:3  
目的:对黄芪注射液临床应用及其疗效进行综述。方法:通过查阅近期国内部分期刊杂志,对黄芪注射液在肺心病、老年肺结核、脑中风、冠心病、流行性出血热、病毒性心肌炎、甲亢、肝病及肾病等临床应用新进展进行综述。结果:黄芪注射液辅助治疗上述疾病疗效满意。结论:黄芪注射液是治疗心脑血管疾病、肾病、肝病等的有效药物。  相似文献   
97.
先天性胆总管囊肿病因及治疗研究的新进展   总被引:5,自引:0,他引:5  
1病因新进展近年来人们普遍认为先天性胆总管囊肿(CongenitalBiliaryDilitation,CBD)由以下两个因素所致:胆总管壁薄弱和远端胆总管梗阻。Spitz犤1犦作了如下实验:结扎新生羊的胆总管远端,该动物模型发生胆总管囊形扩张改变,而结扎成年绵羊的胆总管远端却无扩张,表明:胆总管发育早期胆道薄弱时如果发生梗阻会致使囊肿形成,另有学者用其它动物进行研究,也得到了类似的结果。对CBD患儿进行影像学及组织学研究证明:胆总管囊形扩张与胆总管远端狭窄关系密切犤2犦。Babbit犤3犦于1969年首次提出胰胆管合流异常学说,即胆总管与胰管汇合于十二…  相似文献   
98.
PURPOSE: Cancer accounts for 60.9 billion dollars in direct medical costs and 15.5 billion dollars for indirect morbidity costs. These estimates are derived primarily from national surveys or Federal databases. We derive estimates of the costs of cancer using administrative databases, which include claims and employment-related information on individuals insured by private or Medicare supplemental health plans. METHODS: A retrospective matched-cohort control analysis was performed using 1998 to 2000 databases with information on insurance claims, benefits, and health productivity for 3 million privately insured employees, their dependents, and early retirees. Study patients had new diagnoses of one of seven types of cancer (n = 12,709). Controls without cancer were matched at a 3:1 ratio by demographics. A variable follow-up length was used (maximum of 2 years). Direct costs included health care costs for patients and deductibles and copayments for caregivers. Indirect costs of work absence and short-term disability (STD) were calculated for a subgroup of cancer patients and caregivers. RESULTS: Mean monthly health care costs ranged from 2,187 dollars for prostate cancer to 7,616 dollars for pancreatic cancer, most often driven by hospitalization. Costs for controls were 329 dollars per month. Indirect morbidity costs to employees with cancer averaged 945 dollars, a result of a mean monthly loss of 2.0 workdays and 5.0 STD days. CONCLUSION: The economic burden of cancer is substantial. It is feasible to derive tumor-specific estimates of direct and indirect costs for large numbers of cancer patients using administrative databases. Policy makers charged with providing annual cost-of-cancer estimates should incorporate data obtained from a broad range of sources.  相似文献   
99.
The purpose of this study was to determine the impact of secondary hypoxemia on visual discrimination accuracy after parasagittal fluid percussion injury (FPI). Rats lived singly in test cages, where they were trained to repeatedly execute a flicker-frequency visual discrimination for food. After learning was complete, all rats were surgically prepared and then retested over the following 4-5 days to ensure recovery to presurgery levels of performance. Rats were then assigned to one of three groups [FPI + Hypoxia (IH), FPI + Normoxia (IN), or Sham Injury + Hypoxia (SH)] and were anesthetized with halothane delivered by compressed air. Immediately after injury or sham injury, rats in groups IH and SH were switched to a 13% O2 source to continue halothane anesthesia for 30 min before being returned to their test cages. Anesthesia for rats in group IN was maintained using compressed air for 30 min after injury. FPI significantly reduced visual discrimination accuracy and food intake, and increased incorrect choices. Thirty minutes of immediate posttraumatic hypoxemia significantly (1) exacerbated the FPI-induced reductions of visual discrimination accuracy and food intake, (2) further increased numbers of incorrect choices, and (3) delayed the progressive recovery of visual discrimination accuracy. Thionine stains of midbrain coronal sections revealed that, in addition to the loss of neurons seen in several thalamic nuclei following FPI, cell loss in the ipsilateral dorsal lateral geniculate nucleus (dLG) was significantly greater after FPI and hypoxemia than after FPI alone. In contrast, neuropathological changes were not evident following hypoxemia alone. These results show that, although hypoxemia alone was without effect, posttraumatic hypoxemia exacerbates FPI-induced reductions in visual discrimination accuracy and secondary hypoxemia interferes with control of the rat's choices by flicker frequency, perhaps in part as a result of neuronal loss and fiber degeneration in the dLG. These results additionally confirm the utility of this visual discrimination procedure as a sensitive, noninvasive means of assessing behavioral function after experimental traumatic brain injury.  相似文献   
100.
Vascular cell adhesion molecule 1 (VCAM-1) is a member of immunoglobulin superfamily. The principal ligand for VCAM-1 is integrin α4β/VLA-4 (very late antigen 4). It was reported that VCAM-1 was expressed on macrophages and dendritic cells, but little is known about its function on these professional antigen presenting cells (APC). The present study was performed to investigate the expression of VCAM-1 on macrophages and the role of VCAM-l/VLA-4 in the activation of allogenic T cells by murine macrophages. We analyzed VCAM-1 expression on peritoneal macrophages and macrophage cell line J774A.1 by fluorescence-activated cell sorting (FACS). Using neutralizing antibodies, we further analyzed the role of VCAM-l/VLA-4 interaction in macrophage and allogenic T cell mixed lymphocyte reaction (MLR). We found that VCAM-1 was constitutively expressed on macrophages and its expression level was upregulated by soluble tumor associated antigen (freeze-thaw lysates of FBL-3 leukemia cells) and TNF-a. In MLR assays, we observed that blocking VCAM-l/VLA-4 interaction with anti-VCAM-1 or anti-VLA-4 mAbs caused significant inhibition of the proliferative response and IL-2 production. These results suggest that VCAM-lon macrophages not only facilitates the cell-to-cell contact through adhesive interaction but also plays a role in the costimulation of T cells via its interaction with VLA-4 on the T cells. This work was supported by grants from the National Natural Science Foundation of China.No. (39730420). This is one of papers of the special issue on gene therapy research (Chin J Cancer Res Vol. 9 No. 4 December, 1997).  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