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   362558篇
  免费   33180篇
  国内免费   20612篇
耳鼻咽喉   3660篇
儿科学   5989篇
妇产科学   2278篇
基础医学   24237篇
口腔科学   6507篇
临床医学   42704篇
内科学   37187篇
皮肤病学   4331篇
神经病学   10122篇
特种医学   13605篇
外国民族医学   25篇
外科学   35534篇
综合类   92257篇
现状与发展   95篇
一般理论   11篇
预防医学   40437篇
眼科学   4740篇
药学   42998篇
  469篇
中国医学   30841篇
肿瘤学   18323篇
  2024年   1530篇
  2023年   4201篇
  2022年   10701篇
  2021年   14095篇
  2020年   12100篇
  2019年   7309篇
  2018年   7654篇
  2017年   9903篇
  2016年   8183篇
  2015年   13984篇
  2014年   18600篇
  2013年   22351篇
  2012年   32250篇
  2011年   34279篇
  2010年   30001篇
  2009年   26995篇
  2008年   28224篇
  2007年   27423篇
  2006年   24606篇
  2005年   20499篇
  2004年   14684篇
  2003年   12746篇
  2002年   10143篇
  2001年   8271篇
  2000年   6266篇
  1999年   2685篇
  1998年   1079篇
  1997年   1034篇
  1996年   789篇
  1995年   700篇
  1994年   623篇
  1993年   389篇
  1992年   330篇
  1991年   250篇
  1990年   217篇
  1989年   155篇
  1988年   133篇
  1987年   133篇
  1986年   135篇
  1985年   93篇
  1984年   86篇
  1983年   58篇
  1982年   68篇
  1981年   19篇
  1980年   25篇
  1978年   21篇
  1975年   18篇
  1972年   21篇
  1962年   18篇
  1955年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
41.
42.
Amyloidosis is a systemic disease that usually occurs in the gastrointestinal tract or in muscular or adipose tissue. Primary amyloidosis of the urinary bladder is a rare disease that can mimic bladder cancer on cystoscopic examination as well as in its clinical presentation of painless gross hematuria. This report describes a 49-year-old male with repeated painless gross hematuria, who underwent transurethral resection of a suspected bladder tumor. Pathologic examination revealed papillary urothelial hyperplasia with vascular ectasia and no signs of malignancy. Massive gross hematuria occurred 2.5 years later. Cystoscopy showed multiple papillary lesions with yellowish-brown submucosal plaques on the posterior bladder wall. A second transurethral tumor resection was performed and histologic examination revealed plasma cell infiltration and eosinophilic amorphous deposits in the subepithelial stroma and vascular wall. The deposits were positive for Congo red and apple-green birefringence under polarized light examination but negative for Masson's trichrome stain, indicating that they were not fibrotic in nature. Hence, the diagnosis of amyloidosis of the urinary bladder was confirmed. Screening for amyloidosis was negative in other organ systems and the patient has remained disease-free up to the last follow-up 4 years after the second transurethral resection. Amyloidosis should be considered in the differential diagnosis of patients with recurrent hematuria who have symptoms characteristic of bladder cancer but negative pathologic study for malignancy. Correct diagnosis relies on clinical alertness and the use of a special staining technique during pathologic examination.  相似文献   
43.
手部皮肤套脱伤的治疗   总被引:5,自引:2,他引:3  
目的探讨手部皮肤套脱伤的治疗方法。方法2002年4月-2004年11月,治疗22例手部皮肤套脱伤患者,其中19例分别通过吻合血管、套脱皮肤修薄回植及多切口引流等方法进行修复。另有3例,因无法行套脱皮肤回植而采用腹部带蒂皮瓣修复。结果术后随访3个月-1年。19例套脱皮肤原位回植患者中,13例皮肤完全成活,4例有部分皮缘坏死,经中药换药后愈合,2例行切痂植皮术后治愈。手功能按ATN功能评分评定:优9例,良7例,中3例,优良率为84%,患者对手外形及功能满意。3例腹部皮瓣修复者,皮瓣全部成活。术后随访5个月-1年,手外形及功能明显差于皮肤原位回植者。结论尽可能地回植手部套脱皮肤,对手功能及外形的恢复具有重要意义。  相似文献   
44.
目的 探讨血清肌钙蛋白Ⅰ(cTn-I)对急性脑血管病(ACVD)后心肌损伤的诊断价值.方法 检测160例ACVD患者入院后24h内、3d、7d的血清cTn-I和肌酸激酶同工酶(CK-MB),比较不同病程、不同类型、不同病情程度ACVD患者血清cTn-I和CK-MB的测定结果,观察预后与cTn-I、CK-MB的关系.结果 病后24h内和7d血清cTn-I较CK-MB的阳性率高;脑出血和重症患者病后7d cTn-I仍增高;病后30d内死亡者的cTn-I和CK-MB增高比例高于存活者.结论 血清cTn-I对ACVD后心肌损伤的检测具有比CK-MB更高的敏感性、特异性和更宽的诊断窗口.  相似文献   
45.
处女膜修补手术及麻醉方法的改进   总被引:9,自引:7,他引:2  
目的;增大处女膜粘膜瓣的接触面,减少因麻醉造成的处女膜粘膜水肿,提高修复手术的成功率。方法:手术全部采用1%的卡因行粘膜表面麻醉。53例采用瓦合粘膜瓣法,3例用瓦合粘膜瓣联合阴道粘膜瓣修复法。结果:56例术后一月随访,53例处女膜孔径为一指,成功率94.64%。结论:采用1%的卡因粘膜表面麻醉,瓦合粘膜瓣法及瓦合粘膜联合阴道粘膜瓣修复法对处女膜修复是行之有效的。  相似文献   
46.
李钧  张泺 《眼科研究》1990,8(3):156-158
应用神经组织化学技术观察了兔角膜NA能神经及AchE阳性神经在角膜损伤后的再生,证实术后1月,两种神经均有再生轴突进入植片;术后3月可见交界区和植床内神经密度明显增加;同时,对术后两种神经再生的功能意义进行了讨论。  相似文献   
47.
To clarify the mechanism of postischaemic delayed cornu Ammonis (CA)-1 neuronal death, we studied correlations among calpain activation and its subcellular localization, the immunoreactivity of phosphatidylinositol 4,5-bisphosphate (PIP2) and Ca2+ mobilization in the monkey hippocampus by two independent experimental approaches: in vivo transient brain ischaemia and in vitro hypoxia-hypoglycaemia of hippocampal acute slices. The CA-1 sector undergoing 20 min of ischaemia in vivo showed microscopically a small number of neuronal deaths on day 1 and almost global neuronal loss on day 5 after ischaemia. Immediately after ischaemia, CA-1 neurons ultrastructurally showed vacuolation and/or disruption of the lysosomes. Western blotting using antibodies against inactivated or activated μ-calpain demonstrated μ-calpain activation specifically in the CA-1 sector immediately after ischaemia. This finding was confirmed in the perikarya of CA-1 neurons by immunohistochemistry. CA-1 neurons on day 1 showed sustained activation of μ-calpain, and increased immunostaining for inactivated and activated forms of μ- and m-calpains and for PIP2. Activated μ-calpain and PIP2 were found to be localized at the vacuolated lysosomal membrane or endoplasmic reticulum and mitochondrial membrane respectively, by immunoelectron microscopy. Calcium imaging data using hippocampal acute slices showed that hypoxia-hypoglycaemia in vitro provoked intense Ca2+ mobilization with increased PIP2 immunostaining specifically in CA-1 neurons. These data suggest that transient brain ischaemia increases intracellular Ca2+ and PIP2 breakdown, which will activate calpain proteolytic activity. Therefore, we suggest that activated calpain at the lysosomal membrane, with the possible release of biodegrading enzyme, will cause postischaemic CA-1 neuronal death.  相似文献   
48.
Background :
The aim of this study was to investigate the influence of osteoarthritis of lumbar vertebrae on serum bone formation and resorption marker levels of patients with benign prostatic hypertrophy (BPH).
Methods :
Serum levels of carboxyterminal propeptide of type I procollagen (PICP), alkaline phosphatase (ALP), carboxyterminaltelopeptide of type I collagen (ICTP), and prostate-specific antigen (PSA) were examined in 40 patients with BPH, and the presence of osteoarthritis at the lumbar vertebrae of the patients was evaluated by plain x-ray-p.
Results :
Findings of osteoarthritis were observed in 23 of the 40 patients (58%), and 10 of the patients had severe osteoarthritis (involving at least 2 lumbar vertebral bodies). The serum levels of PICP, ALP, ICTP, and PSA of the patients without osteoarthritis findings were not different from those of the patients with osteoarthritis or severe osteoarthritis.
Conclusion :
The influence of osteoarthritis on serum bone formation and resorption marker levels of patients with BPH appears to be rather slight, if there is any influence at all.  相似文献   
49.
50.
By a double-labeling method combining the retrograde tracing of horseradish peroxidase and the immunocytochemical technique, serotonin-like immunoreactive neurons in the midbrain periaqueductal gray (PAG) and nucleus raphe dorsalis (DR) of the rat were observed to send projection fibers to the nucleus parafascicularis of the thalamus bilaterally with an ipsilateral dominance. These serotonin-containing projecting neurons were observed mainly at the middle-caudal levels of the ventrolateral subdivision of the PAG and less at the middle-rostral levels of the DR.  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