全文获取类型
收费全文 | 13651篇 |
免费 | 941篇 |
国内免费 | 248篇 |
专业分类
耳鼻咽喉 | 613篇 |
儿科学 | 272篇 |
妇产科学 | 153篇 |
基础医学 | 973篇 |
口腔科学 | 150篇 |
临床医学 | 1529篇 |
内科学 | 2042篇 |
皮肤病学 | 156篇 |
神经病学 | 325篇 |
特种医学 | 637篇 |
外国民族医学 | 5篇 |
外科学 | 1184篇 |
综合类 | 2316篇 |
预防医学 | 764篇 |
眼科学 | 102篇 |
药学 | 856篇 |
13篇 | |
中国医学 | 329篇 |
肿瘤学 | 2421篇 |
出版年
2024年 | 28篇 |
2023年 | 136篇 |
2022年 | 378篇 |
2021年 | 434篇 |
2020年 | 396篇 |
2019年 | 343篇 |
2018年 | 374篇 |
2017年 | 413篇 |
2016年 | 426篇 |
2015年 | 452篇 |
2014年 | 893篇 |
2013年 | 770篇 |
2012年 | 821篇 |
2011年 | 913篇 |
2010年 | 746篇 |
2009年 | 693篇 |
2008年 | 733篇 |
2007年 | 757篇 |
2006年 | 593篇 |
2005年 | 544篇 |
2004年 | 448篇 |
2003年 | 375篇 |
2002年 | 336篇 |
2001年 | 313篇 |
2000年 | 252篇 |
1999年 | 259篇 |
1998年 | 213篇 |
1997年 | 193篇 |
1996年 | 193篇 |
1995年 | 193篇 |
1994年 | 168篇 |
1993年 | 144篇 |
1992年 | 98篇 |
1991年 | 85篇 |
1990年 | 94篇 |
1989年 | 76篇 |
1988年 | 68篇 |
1987年 | 75篇 |
1986年 | 39篇 |
1985年 | 61篇 |
1984年 | 63篇 |
1983年 | 23篇 |
1982年 | 47篇 |
1981年 | 39篇 |
1980年 | 35篇 |
1979年 | 30篇 |
1978年 | 14篇 |
1977年 | 8篇 |
1976年 | 16篇 |
1972年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
103.
Platelet-activating factor (PAF) is a naturally occurring phospholipid that acts as a pleiotropic mediator and mediates cell-cell reactions under physiological and pathological conditions. Recently, it has been shown that PAF is a strong secretagogue of mucous glycoprotein in the airways, suggesting its role in mucous glycoprotein secretion and the pathogenesis of otitis media with effusion. In the current study, we examined the effect of PAF on mucous glycoprotein secretion in cultured chinchilla middle ear epithelial cells. PAF at 1 M significantly stimulated mucous glycoprotein secretion from cultured chinchilla middle ear epithelial cells. This action was concentration-dependent, with secretions reaching near maximum when the cells were incubated with PAF at 100 M. In a time-dependent study, PAF demonstrated an initial rapid stimulation of mucous glycoprotein secretion, followed by a gradual increase thereafter. A six-fold increase was seen in the first 2 h compared with controls. Cycloheximide, a protein synthesis inhibitor, demonstrated an inhibitory effect on PAF-stimulated mucous glycoprotein secretion in this study. These findings suggest that PAF plays an important role in the pathogenesis of otitis media with effusion by stimulating mucous glycoprotein secretion in vitro.Supported by NIH grant P0I-D000133 from the National Institute on Deafness and Other Communication Disorders. 相似文献
104.
G. Mantovani A. Macciò R. Versace M. Pisano P. Lai S. Esu M. Ghiani D. Dessì E. Turnu M. C. Santona R. Cherchi G. S. Del Giacco 《Journal of molecular medicine (Berlin, Germany)》1995,73(8):409-416
This work was designed to study the proliferative response of tumor-associated lymphocytes (TAL) from neoplastic effusions against autologous tumor cells and the immunophenotype pattern of TAL from neoplastic effusions and that of PBMC of the same patients. We also compared the serum levels of the cytokines interleukin (IL) 1, 2 and 6, tumor necrosis factor- (TNF) and soluble IL-2 receptor (sIL-2R) with those present in neoplastic effusions of the same patients. Moreover, we examined the ability of TAL and peripheral blood mononuclear cells (PBMC) to produce and release the cytokines and sIL-2R and to express membrane CD25 following their stimulation with phytohemagglutinin (PHA) in vitro. Finally, we compared the cytokines/sIL-2R production and membrane CD25 expression by PHA-stimulated PBMC of the patients with neoplastic effusions with a series of 90 cancer patients without neoplastic effusions and 20 normal healthy subjects. Thirteen neoplastic pleural and eight peritoneal effusions were collected from 11 patients with primary lung cancer, 7 with primary epithelial ovarian cancer, 1 with breast cancer, 1 with pleural mesothelioma, and 1 with pancreatic cancer. The proliferative response of TAL from neoplastic effusions against autologous tumor cells was lower than the response to PHA, IL-2, and anti-CD3, but significant. The percentage distribution of CD3+ and CD8+ lymphocyte subpopulations was higher in peritoneal than in pleural effusions, while the CD16+ subset was higher in pleural than in peritoneal effusions. The percentage distribution of CD16+ was significantly lower in pleural effusions than in PBMC of patients with pleural effusions. The CD39 antigen was higher on TAL from peritoneal effusions than on PBMC of the same patients. The levels of IL-1 and sIL-2R in peritoneal effusions did not differ from those measured in the sera of the same patients, while the levels of IL-2, IL-6, and TNF were higher in the peritoneal effusions. The levels of IL-2, IL-6, TNF, and sIL-2R, but not IL-1, in pleural effusions were significantly higher than those found in the sera of the same patients. The amounts of IL-2 and IL-6 produced by TAL were generally higher than those released by PBMC. The secretion of cytokines IL-1, IL-2, and sIL2R by PHA-stimulated PBMC was lower, but IL-1 and IL-6 secretion was higher in cancer patients with neoplastic effusions than in either cancer patients without neoplastic effusions or normal subjects. The CD25 expression on PHA-stimulated PBMC derived from cancer patients with neoplastic effusions was in the same range as that of cancer patients without neoplastic effusions and normal subjects. These findings suggest that TAL may be able to produce cytokines and may be amenable to immune manipulation.Abbreviations
FITC
Fluorescein-isothiocyanate
-
IL
Interleukin
-
mAb
Monoclonal antibody
-
MHC
Major histocompatibility complex
-
NK
Natural killer
-
PBMC
Peripheral blood mononuclear cells
-
PHA
Phytohemagglutinin
-
TAL
Tumor-associated lymphocytes
-
TIL
Tumor-infiltrating lymphocytes
-
TNF
Tumor necrosis factor-
-
sIL-2R
Soluble interleukin-2 receptor 相似文献
105.
目的 探讨细胞形态学在鉴别噬血细胞综合征(HS)和恶性组织细胞病(MH)的诊断价值。方法 应用瑞-姬氏染色,普通光镜下对39例HS和42例MH患者的骨髓片、外周血片、外周血液浓缩片中的细胞形态学进行了详细观察,并结合外周血涂片碱性磷酸酶染色的结果进行了综合分析。结果 HS与MH在骨髓和外周血中的细胞数量及形态学变化方面均有明显不同,外周血涂片碱性磷酸酶染色亦存在明显差异。结论 细胞形态学检查是鉴别HS与MH的重要手段,在确诊HS与MH方面具有重要价值。 相似文献
106.
107.
为了解分泌性中耳炎( O M E)对内耳听觉功能的影响,对 O M E220 例、304 耳分别进行纯音测听及声阻抗测定。结果表明,部分 O M E 患者骨导听阈升高,除造成传音性耳聋外,合并感音性耳聋( S N H L)为318% ,并随着病程延长, S N H L 发病率增高。提示应积极有效地治疗本病,应用扩血管及营养神经药物可防治 S N H L的发生。 相似文献
108.
目的 探讨血清可溶性白细胞介素2 受体(s I L2 R)水平与恶性肿瘤患者的病期及疗效的关系。方法 采用双抗体夹心 E L I S A 法检测159 例恶性肿瘤患者放疗前后血清s I L2 R 水平。结果 恶性肿瘤患者放疗前血清s I L2 R 水平明显高于正常对照组( P< 005);放疗后血清s I L2 R 水平明显低于放疗前( P < 0001);晚期患者(Ⅲ+ Ⅳ期)不论是放疗前或放疗后 s I L2 R 水平均明显高于早期患者(Ⅰ+ Ⅱ期)( P < 005);各类恶性肿瘤之间血清s I L2 R 水平无显著性差异( P >005)。结论 s I L2 R水平在各种恶性肿瘤中的表达无特异性;检测恶性肿瘤患者s I L2 R 放疗前后水平,是对病情估计和治疗疗效评价的一项参考指标。 相似文献
109.
目的 观察生物制剂胸腔内灌注对癌性胸水的疗效。方法 采用胸腔穿刺硅胶导管灌注高聚金葡素和白细胞介素Ⅱ生物制剂或化疗药物对照。结果 高聚金葡素组20例,有效率为82.0%,对照组丝裂霉素组20例,有效率为45%,白细胞介素Ⅱ组18例,有效率为83.3%。对照组丝裂霉素组18例,有效率为44.4%。结论经导管灌注生物制剂高聚金葡素或白细胞介素Ⅱ,其疗效明显优于胸腔内化疗。 相似文献
110.
Chaudhary S 《Indian journal of pediatrics》1996,63(4):433-436
Otitis media is a common pediatric problem. It is well established that over half of infants and children with acute otitis
media may have spontaneous recovery. Since it is difficult to predict the course (self-limited versus serious disease) all
the children with acute suppurative otitis media need to be treated with antibiotics. Amoxicillin is still the initial antibiotic
of choice. There are several alternate antibiotics available with activity against beta-lactamase positive bacteria. These
agents have no advantage over amoxicillin in infections due to penicillin resistant pneumococci. Recent use of beta-lactam
antibiotics and/or attendance in a day care where there is frequent use of antibiotics are predisposing factors for penicillin
resistant pneumococcal infection. In such cases after tympanocentesis, higher dose of amoxicillin, clindamycin or intramuscular
ceftriaxone should be considered. Secretory otitis media does not need to be treated with antibiotics unless the patient is
in high risk group. Prophylactic use of antibiotics should be actively discouraged. Influenza and pneumococcal vaccination
(2 years or older) should be encouraged in children with recurrent episodes of acute otitis media. Breast feeding should be
encouraged. 相似文献