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   19143篇
  免费   1664篇
  国内免费   1391篇
耳鼻咽喉   184篇
儿科学   146篇
妇产科学   246篇
基础医学   2267篇
口腔科学   213篇
临床医学   2293篇
内科学   3383篇
皮肤病学   189篇
神经病学   926篇
特种医学   717篇
外国民族医学   11篇
外科学   2045篇
综合类   3155篇
一般理论   2篇
预防医学   1075篇
眼科学   562篇
药学   2024篇
  15篇
中国医学   960篇
肿瘤学   1785篇
  2024年   63篇
  2023年   317篇
  2022年   744篇
  2021年   958篇
  2020年   674篇
  2019年   652篇
  2018年   725篇
  2017年   572篇
  2016年   607篇
  2015年   852篇
  2014年   1047篇
  2013年   861篇
  2012年   1368篇
  2011年   1508篇
  2010年   856篇
  2009年   718篇
  2008年   1042篇
  2007年   1004篇
  2006年   971篇
  2005年   953篇
  2004年   640篇
  2003年   590篇
  2002年   518篇
  2001年   459篇
  2000年   512篇
  1999年   455篇
  1998年   343篇
  1997年   304篇
  1996年   270篇
  1995年   258篇
  1994年   170篇
  1993年   125篇
  1992年   166篇
  1991年   158篇
  1990年   127篇
  1989年   124篇
  1988年   112篇
  1987年   99篇
  1986年   95篇
  1985年   61篇
  1984年   29篇
  1983年   23篇
  1982年   11篇
  1981年   17篇
  1980年   10篇
  1979年   7篇
  1978年   7篇
  1977年   3篇
  1976年   4篇
  1974年   2篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
OBJECTIVE: To investigate the relationship between the plasminogen activator inhibitor (PAI-1) polymorphisms and endometrial hypoplasia in infertile women. METHODS: The study was conducted in 105 primary infertile patients with endometrial hypoplasia diagnosed by pathology and the thickness of endometrium by B-mode ultrasound and 85 controls who were not pregnant and had normal fertility. The -675 4G/5G polymorphism in the PAI-1 gene was detected by polymerase chain reaction-restriction fragment length polymerphim analysis. RESULTS: The frequencies of 4G/4G genotype and 4G allele of the PAI-1 gene were higher in the patient group (48.6% and 66.2%) than in the normal controls (22.4% and 47.1%) (P < 0.01). ThePAI-1 4G/4G genotype was significantly associated with endometrial hypoplasia in the infertile patients (OR=4.9, 95% CI: 2.10-10.12). CONCLUSION: The present findings suggest that the 4G/5G polymorphism of the PAI-1 gene was associated with endometrial hypoplasia in infertile patients.  相似文献   
22.
目的:探讨超声检查在诊断乳腺典型髓样癌中的临床意义。方法:按严格的病理诊断学标准将病例重新分类为乳腺典型髓样癌和非典型髓样癌,比较两者间声像学特征的异同。结果:32例中有13侧重新诊断为乳腺典型髓样癌;另外19例为非典型髓样癌。13例典型髓样癌患者中的10例边界整齐光滑;全部19例非典型髓样癌病人没有一例边界光滑,或者边界呈锯齿状(16例),或者边界光滑伴局部不规则(3例)。非典型与典型髓样癌间肿瘤边界的规则性有明显的差异。结论:如果超声检查提示肿瘤边界呈锯齿状或肿瘤边界光滑伴局部不规则,应行整个肿瘤的病理评估防止典型髓样癌的过诊断。  相似文献   
23.

Objective  

To observe the effects of essential garlic oil (EGO) on vascular cell adhesive molecule-1 (VCAM-1) expression of endothelial cells and monocyte-endothelial cell adhesion rate induced by interleukin-lα(IL-lα).  相似文献   
24.
Dai  Wei  Zhuang  Zong  Ling  Haiping  Yang  Yongbo  Hang  Chunhua 《Neurosurgical review》2021,44(1):515-527
Neurosurgical Review - To quantitatively synthesize the comparative efficacy and safety of the most common surgical approaches including endonasal transsphenoidal endoscopic surgery (ETES),...  相似文献   
25.
PurposeTo investigate the clinical characteristics, chemosensitivity, and outcome of metastatic upper tract urothelial carcinoma (UTUC).Patients and MethodsRecords of patients with metastatic UTUC since January 2005 were retrieved from a database that included clinical and survival data. Statistical analyses including survival and multivariate analyses of factors were respectively performed by the Kaplan-Meier method and Cox proportional hazard model.ResultsA total of 250 consecutive UTUC cases were evaluated. There were 56 patients (22.4%) with initially diagnosed stage IV disease. The most common metastatic sites were lung (39.6%), distant lymph nodes (39.2%), bone (19.6%), liver (18.0%), and adrenal gland (7.2%), respectively, and the local recurrence rate was 10.4%. Two hundred thirteen patients received first-line chemotherapy. The overall response rate was only 28.7% and the median progression-free survival time was only 5.0 months. The overall survival time of the cohort was 18.0 months. Multivariate analyses showed that initially diagnosed stage IV disease, number of metastatic organs ≥3, no response to chemotherapy and cycles of chemotherapy ≤2 were adverse prognosticators for overall survival.ConclusionUTUC presented to be more prone to metastasize than locally recur and thought to have low chemosensitivity. Stage IV disease at initial diagnosis, number of metastatic organs, response and cycles of chemotherapy were independent prognosticators for metastatic UTUC.  相似文献   
26.
W Mao  L Zeng  Q Ma  Y Chen  Z Dai  P Tang  X Guo  D Li  W Su 《眼科学报》1990,6(3-4):88-90
We report here the preliminary effects of zinc iontophoresis in treatment of 26 Rp patients who had decreased zinc serum level or abnormal ratio of serum copper to zinc. Through more than 20 to 30 times of therapy, the vision of 15.38% eyes increased more than "3 lines", 4% eyes increased more than 5 degrees in the visual field, 13.46% eyes improved in dark adaptation threshold (greater than 1.0), the visual functions of the rest eyes were slightly improved or unimproved. The fundus didn't change before & after treatment. There were no changes of ERG in 8 eyes of 4 cases. In addition, the advantages and disadvantages between Zn iontophoresis and Zn compound taken orally, the improvement of vision by direct electric current therapy, the relationship between the metabolism of Zn element and Vit A and influence of Zn over the mechanism of dark adaptation were also briefly discussed.  相似文献   
27.
目的 :探索口腔粘膜扁平苔藓 (OLP) P53蛋白的表达及其在癌变诊断中的应用价值。方法 :采用 S- P免疫组化方法 ,观察在 2 5例 OLP、2 0例鳞癌 (OSCC)中 P53蛋白的表达。结果 :1 P53蛋白的阳性表达在 OLP早期已出现 ,各组间 P53阳性表达率间有显著性差异。2在 OSCC中其阳性表达率高达 80 % ,随着细胞异常增生程度的增高而增高。结论 :1在 OSCC的形成过程中 ,抑癌基因 P53的失活可能参与调节作用 ;2 P53蛋白作为判断 OLP癌变的辅助性参考指标 ,具有一定的可行性  相似文献   
28.
In 1972, HaelnOPhilus influenzae (HI) was firstlydiscovend being resistant against alnpicillin by producing5-lac~e, since then, studies on the rests~ mechamsms and the moleCular basis of 5-lactalnaSe Pwhctionhave been increasing year by yeax abroadll]. In 1978,Bryan et .l[2] first reported sabins of HI Producing 0-lactamaSe, which was mediated by plaaed, from then on,many stUdies foeused on 3-lactamase encoded by PlaSnddin HI and its relation with ampicillin resisboce. In ourco~, few st…  相似文献   
29.
4-硒硫酸酯多糖的体内抗瘤作用   总被引:2,自引:1,他引:1  
目的 观察 4-硒硫酸酯多糖 (Se-carra)的体内抗瘤作用。方法 于小鼠右腋皮下接种瘤细胞 2 4h后开始给药 ,连续 10天 ,观察其抑瘤率 ;小鼠腹腔接种肿瘤细胞前或接种后连续给药 10天 ,观察动物的生存时间。结果  4-硒硫酸酯多糖能明显抑制肿瘤细胞的生长 ,延长小鼠的生存期。结论  4-硒硫酸酯多糖体内给药有良好的抗瘤效果 ,值得进一步研究。  相似文献   
30.
采用抽样研究方法,对438名不同专业、不同层次的大学生进行了医德认知调查,以了解大学生对医德基本知识掌握的情况,结果表明,大学生对开设医学伦理学课必要性认识均率为62.9%,课外经常阅读医德书籍均率为22.75%,对中外基德发展史各朝代典型的人物及代表作了解的均率为31.1%,文中对调查结果进行了分析。  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