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   86364篇
  免费   9066篇
  国内免费   7068篇
耳鼻咽喉   648篇
儿科学   809篇
妇产科学   985篇
基础医学   10569篇
口腔科学   1607篇
临床医学   12354篇
内科学   12087篇
皮肤病学   715篇
神经病学   5151篇
特种医学   3145篇
外国民族医学   56篇
外科学   8024篇
综合类   15226篇
现状与发展   22篇
一般理论   13篇
预防医学   5486篇
眼科学   2923篇
药学   9094篇
  100篇
中国医学   5815篇
肿瘤学   7669篇
  2024年   104篇
  2023年   1355篇
  2022年   2301篇
  2021年   4483篇
  2020年   3903篇
  2019年   3204篇
  2018年   3432篇
  2017年   2870篇
  2016年   2818篇
  2015年   4295篇
  2014年   5280篇
  2013年   4466篇
  2012年   6575篇
  2011年   7624篇
  2010年   4571篇
  2009年   3579篇
  2008年   4589篇
  2007年   4447篇
  2006年   4623篇
  2005年   4655篇
  2004年   2747篇
  2003年   2673篇
  2002年   2222篇
  2001年   1932篇
  2000年   2064篇
  1999年   2156篇
  1998年   1419篇
  1997年   1345篇
  1996年   1088篇
  1995年   1017篇
  1994年   844篇
  1993年   535篇
  1992年   603篇
  1991年   509篇
  1990年   465篇
  1989年   420篇
  1988年   347篇
  1987年   282篇
  1986年   224篇
  1985年   178篇
  1984年   81篇
  1983年   50篇
  1982年   41篇
  1981年   36篇
  1980年   24篇
  1979年   21篇
  1964年   1篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
61.
62.
Caudal regression syndrome (CRS) is a rare congenital malformation with varying degrees of early gestational developmental failure. It is characterized by agenesis of the sacrum and lumbar spine, with lower limb neurological deficit and accompanying deformities of the pelvis, lower extremities, genitourinary, and gastrointestinal systems. We report a case of CRS associated with rare complex congenital heart defect, that is, heterotaxy syndrome, diagnosed prenatally.  相似文献   
63.
We sought to optimize direct intravenous infusion of calcium gluconate (CaGlu) for maintaining plasma ionized calcium concentration ([Ca2+]) and preventing hypocalcemic reactions during 34 consecutive 1-volume therapeutic plasma exchanges (TPEs) in eight patients. CaGlu, 2 g in 50 mL of 0.9% NaCl, was prepared by our hospital pharmacy and infused at either 1.0 or 1.6 g/h during alternate TPE. Plasma [Ca2+] was monitored at intervals of 20 to 30 minutes. At 1 g/h of CaGlu, plasma [Ca2+] fell by 8.35% after 40 to 50 minutes and then plateaued. At 1.6 g/h of CaGlu, plasma [Ca2+] fell by 6% after 20 to 30 minutes and then plateaued. The difference at 40 to 50 minutes was significant (P = .015). Hypocalcemic reactions were noted in three patients during 5 of 17 TPE at 1.0 g/h (all after 40 to 60 minutes) but 0 of 17 TPE at 1.6 g/h (P = .044). CaGlu at 1.6 g/h stabilized plasma [Ca2+] and appears to prevent hypocalcemic reactions during TPE.  相似文献   
64.
教学是教与学的统一,良好的教学效果需要师生的共同努力和积极配合,形成双轮驱动。由于诸多因素影响,我国目前临床实践教学中普遍存在教与学双重动力不足的现象。有鉴于此,西安交通大学第一附属医院通过建立以规范 - 示范 - 定期活动为主线的临床教学质量提升体系以及在临床实习中推行首轮负责制 - 责任导师 - 第三方考核平台等举措,探索有效机制,增强师生投入,深化教学改革,有效提升了临床实践教学质量。  相似文献   
65.
66.
67.
Objective: The differences of ovarian morphology, reproductive hormones, glucose and lipid metabolism and intestinal bacteria in rats with polycystic ovary syndrome (PCOS) induced by triazole were compared. Method: Eighteen 21 SPF female SD rats were randomly divided into group A (3-week group), group B (5-week group) and group D (control group) by random number table.Group A received letrozole + CMC-Na mixture by gavage in the first 3 weeks and CMC-Na solution by gavage in the last 2 weeks, group B received letrozole + CMC-Na mixture by gavage for 5 weeks, and group D received CMC-Na solution by gavage for 5 weeks, and all three groups of rats were fed with normal diet.At the end of gavage, the body weight of rats in each group was observed, the histological changes of ovaries were observed by hematoxylin-eosin (HE) staining, the serum levels of estradiol (E2), follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T), total cholesterol (TC), triglyceride (TG), fasting blood glucose (Glu), fasting insulin (FINS) and lipopolysaccharide (LPS) were measured by enzyme-linked immunosorbent assay (ELISA), and the LH/FSH ratio and insulin resistance index (HOMA IR) were calculated; the intestinal bacteria of rats were detected by 16S rRNA technique. Result: 1. Comparison of ovary histomorphology: Under light microscope, multiple luteum and oocytes were observed in mature follicles in group D, and granulosa cells were orderly arranged and multilayered, without cystic dilated follicles. There were no mature follicles in the ovarian tissues of group A and GROUP B. The follicles were irregular in structure and more cystic dilated follicles were visible. The number of granular cells in some follicles decreased or even disappeared. 2. Comparison of sex hormone levels: compared with group D, T level in group B was significantly increased (P < 0.001), and T level in group A had an upward trend (P > 0.05); The LH/FSH levels in group A and B were significantly increased (P < 0.001; P < 0.001). Compared with group A, E2 in group B was significantly decreased (P < 0.05) and T was significantly increased (P < 0.01). 3. Comparison of glucose and lipid metabolism levels: Compared with group D, TC levels in groups A and B were significantly increased (P < 0.01; P < 0.01). Compared with group A, TG in group B was significantly increased (P < 0.05). There were no significant differences in Glu, FINS and HOMA-IR levels among all groups. 4. Comparison of LPS levels: Compared with group D, the serum LPS levels of rats in groups A and B were significantly increased (P < 0.001; P < 0.01). 5. Intestinal flora analysis and comparison: At the phylum level, compared with group D, the abundance of Firmicutes in group B increased (P < 0.01), Firmicutes in group A showed an upward trend (P > 0.05), and the abundance of Bacteroidetes in groups A and B decreased (P < 0.05). At the genus level, compared with group D, Lactobacillus in group B increased (P < 0.01). The results of LEfSe analysis showed that there were differences in the composition of various intestinal bacteria among the three groups (LDA > 3).Conclusion: The phenotype of PCOS rats was related to the length of modeling, and the phenotypic characteristics of PCOS in rats at 5 weeks of modeling were more typical than those in rats at 3 weeks of modeling; PCOS can cause changes in intestinal flora, and the changes in the structure of intestinal flora between groups are related to different modeling duration.  相似文献   
68.
69.
Gastric cancer (GC) is a malignancy with a high incidence and mortality. The tumor immune microenvironment plays an important role in promoting cancer development and supports GC progression. Accumulating evidence shows that GC cells can exert versatile mechanisms to remodel the tumor immune microenvironment and induce immune evasion. In this review, we systematically summarize the intricate crosstalk between GC cells and immune cells, including tumor-associated macrophages, neutrophils, myeloid-derived suppressor cells, natural killer cells, effector T cells, regulatory T cells, and B cells. We focus on how GC cells alter these immune cells to create an immunosuppressive microenvironment that protects GC cells from immune attack. We conclude by compiling the latest progression of immune checkpoint inhibitor-based immunotherapies, both alone and in combination with conventional therapies. Anti-cytotoxic T-lymphocyte-associated protein 4 and anti-programmed cell death protein 1/programmed death-ligand 1 therapy alone does not provide substantial clinical benefit for GC treatment. However, the combination of immune checkpoint inhibitors with chemotherapy or targeted therapy has promising survival advantages in refractory and advanced GC patients. This review provides a comprehensive understanding of the immune evasion mechanisms of GC, and highlights promising immunotherapeutic strategies.  相似文献   
70.
中医学古籍中罕有关于“胰腺”的明确记载,缺乏直观、系统的理论论述。本文试图通过对各个时期具有代表性的医学典籍所记载内容的分析,结合现代解剖学相关理论,梳理中医学对胰腺实体解剖的认识过程。通过分析,笔者认为中医学对胰腺实体解剖的认识具有阶段性:①先秦两汉时期,存在胰腺实体解剖,但并非认为胰腺是脏器;②唐宋时期,胰腺实体解剖更加清晰,在医学上胰腺附属于脾,并非为独立的脏器;③明清时期,胰腺实体解剖明确,部分医家以独立脏器论之,出现“脾”、“胰”之争。中医学理论缺少对胰腺的单独论述,目前学界的主流观点多为“胰属脾”,线性归属以脾笼统代之略显单薄,不利于理论的丰富与发展。笔者认为胰腺藏象应独立于脾单独讨论,现代解剖学对胰腺命名同一,形态结构清楚,位置描述明确,可直接补充进中医学胰腺藏象(藏)理论中,为完善胰腺藏象理论搭建解剖学基础。  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