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   45425篇
  免费   2404篇
  国内免费   152篇
耳鼻咽喉   613篇
儿科学   2735篇
妇产科学   750篇
基础医学   5304篇
口腔科学   1182篇
临床医学   3355篇
内科学   8463篇
皮肤病学   1185篇
神经病学   2739篇
特种医学   1452篇
外科学   7002篇
综合类   1354篇
一般理论   21篇
预防医学   2245篇
眼科学   1662篇
药学   4403篇
  1篇
中国医学   366篇
肿瘤学   3149篇
  2023年   368篇
  2022年   1062篇
  2021年   1817篇
  2020年   979篇
  2019年   1156篇
  2018年   1574篇
  2017年   1155篇
  2016年   1499篇
  2015年   1495篇
  2014年   2232篇
  2013年   2536篇
  2012年   3598篇
  2011年   3575篇
  2010年   2104篇
  2009年   1681篇
  2008年   2396篇
  2007年   2451篇
  2006年   2218篇
  2005年   1973篇
  2004年   1825篇
  2003年   1566篇
  2002年   1331篇
  2001年   831篇
  2000年   743篇
  1999年   632篇
  1998年   305篇
  1997年   242篇
  1996年   237篇
  1995年   206篇
  1994年   174篇
  1993年   146篇
  1992年   370篇
  1991年   354篇
  1990年   377篇
  1989年   347篇
  1988年   288篇
  1987年   253篇
  1986年   242篇
  1985年   231篇
  1984年   179篇
  1983年   123篇
  1982年   69篇
  1981年   78篇
  1980年   71篇
  1979年   112篇
  1978年   74篇
  1977年   92篇
  1976年   69篇
  1973年   63篇
  1971年   62篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
31.
We report a seven-year-old girl who presented with a sudden tumor apoplexy due to a parasagittal hemangiopericytoma. Following tumor excision, the child was noted to have bilateral optic nerve dysfunction and progressive papilledema, despite rapid overall neurological improvement. Based on the clinical features, we feel that this case represents an unusual form of visual deterioration related to impaired CSF absorption somehow precipitated by the acute tumour apoplexy. This unusual case of blindness responded significantly to CSF shunting. Several reports exist describing raised intracranial pressure with papilledema caused by nonthrombotic sinus occlusion due to tumors in proximity to the posterior superior sagittal sinus, torcular herophili and the jugular outlet. Communicating hydrocephalus, pseudotumor syndrome or intracranial venous sinus obstruction should be considered when otherwise inexplicable visual loss coexists with optic nerve dysfunction and papilledema. We emphasize the importance of a thorough search for the cause of visual loss.  相似文献   
32.
33.
34.
35.
36.
Estimation of T and B lymphocytes was done in 50 patients of enteric fever, 50 duration matched non enteric fever patients and 50 normal healthy individuals. The difference in both early and late rosette forming T lymphocytes was found to be statistically significant in enteric versus non-enteric patients. Significant difference was also observed in enteric versus normal individuals in case of late rosette forming T lymphocytes.  相似文献   
37.
38.
Even though a variety of adverse effects caused by sweeteners, flavorings, and dyes in susceptible individuals have been reported, there is no good single reference with information about these substances in pediatric antimicrobials. Data on sweeteners, flavorings, and dyes in 91 antimicrobial preparations were collected. Sucrose was present in 74 (85%) of 87 preparations, followed by saccharin in 30 (34%) preparations. Mannitol, lactose, and sorbitol were each present in 7 preparations. None of the preparations were free of sweeteners. Thirty-four (37%) of 91 preparations did not specify the flavoring content. While cherry was the most common flavoring used, there were 25 other flavorings. Thirteen different dyes and coloring agents were used in these antimicrobials. Red dye no. 40 was present in 45% of preparations. Tables detailing sweeteners, flavorings, and dyes in different groups of antimicrobials (amoxicillin, ampicillin, cephalosporins, erythromycin, penicillins, sulfonamides, and others) and adverse effects reported with these inert ingredients are presented. These tables should be helpful to physicians in selecting an antimicrobial containing a different sweetener and/or dye when an adverse reaction occurs.  相似文献   
39.
The genotoxic effect of an extract of smoke-dried meat was assayed by employing in vivo sperm head shape abnormality. A significant dose responsive mutagenic effect was observed using the sperm head shape abnormality test. The result indicates that higher doses i.e., 100 and 200 mg/kg body wt. of smoke meat extract, significantly induced sperm head shape abnormality as compared to lower doses i.e., 20 mg/kg body wt. and control.  相似文献   
40.
The mitogenic, chemotactic, and synthetic responses of rat periodontal ligament (PDL) fibroblastic cells to epidermal growth factor (EGF), transforming growth factor-beta (TGF-beta), recombinant human platelet-derived growth factor (rhPDGF)-AB, rhPDGF-BB, natural (n) PDGF-AB, and insulin-like growth factor-I (IGF-I) were examined in vitro using PDL cells obtained from the coagulum of healing tooth sockets. PDGFs and IGF-I have potent and comparable mitogenic effects on PDL fibroblastic cells. The maximum mitogenic effect of PDGFs was observed at the concentration of 10 ng/ml, whereas that of IGF-I was seen at concentrations higher than 100 ng/ml. In contrast, EGF induced moderate, and TGF-beta inhibitory mitogenic responses. The combination of rhPDGF-AB with either EGF or TGF-beta demonstrated comparable mitogenic potency, equivalent to the level of PDGF alone regardless of the mitogenic effect of other growth factors. The combination of rhPDGF-AB and IGF-I, however, showed a synergistic effect revealing the highest mitogenic effect among all individual growth factors as well as any combinations of the growth factors tested. Similarly, PDL fibroblastic cells demonstrated strong chemotactic responses to both IGF-I and PDGFs. The maximum effect was observed by IGF-I at concentrations higher than 10 ng/ml, followed by rhPDGF-BB at 0.1 ng/ml, rhPDGF-AB and nPDGF at concentrations ranging from 0.1 to 1 ng/ml. TGF-beta revealed no, and EGF slightly increased, chemotactic effects. IGF-I slightly enhanced the synthesis of total protein, whereas other factors had no significant effect. However, both rhPDGF-AB and TGF-beta stimulated collagen synthesis. On the other hand, IGF-I showed no effect on collagen synthesis, while EGF suppressed collagen synthesis. These findings suggest that rhPDGF-BB and IGF-I stimulate proliferation and chemotaxis of PDL fibroblastic cells. In addition, the combination of these growth factors further increases the mitogenic effect. rhPDGF-AB also stimulates collagen synthesis by PDL fibroblastic cells. Thus, rhPDGF-BB and IGF-I may have important roles in promotion of PDL healing, and consequently, may be useful for clinical application in periodontal regenerative procedures.  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