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   2061篇
  免费   137篇
  国内免费   32篇
耳鼻咽喉   50篇
儿科学   37篇
妇产科学   20篇
基础医学   273篇
口腔科学   45篇
临床医学   150篇
内科学   380篇
皮肤病学   104篇
神经病学   123篇
特种医学   388篇
外科学   254篇
综合类   12篇
预防医学   62篇
眼科学   24篇
药学   177篇
  2篇
中国医学   8篇
肿瘤学   121篇
  2023年   9篇
  2022年   31篇
  2021年   74篇
  2020年   42篇
  2019年   45篇
  2018年   71篇
  2017年   43篇
  2016年   71篇
  2015年   90篇
  2014年   109篇
  2013年   80篇
  2012年   169篇
  2011年   123篇
  2010年   87篇
  2009年   73篇
  2008年   114篇
  2007年   111篇
  2006年   89篇
  2005年   73篇
  2004年   70篇
  2003年   56篇
  2002年   43篇
  2001年   43篇
  2000年   59篇
  1999年   39篇
  1998年   37篇
  1997年   29篇
  1996年   29篇
  1995年   26篇
  1994年   24篇
  1993年   26篇
  1992年   9篇
  1991年   9篇
  1990年   8篇
  1989年   35篇
  1988年   21篇
  1987年   29篇
  1986年   19篇
  1985年   28篇
  1984年   15篇
  1983年   13篇
  1982年   7篇
  1981年   8篇
  1980年   12篇
  1979年   5篇
  1978年   4篇
  1977年   12篇
  1976年   8篇
  1970年   1篇
  1969年   2篇
排序方式: 共有2230条查询结果,搜索用时 15 毫秒
1.
The FIGNL1 gene was proven to be a new subfamily member of ATPases associated with diverse cellular activities (AAA proteins). In this in vitro study, the AAA proteins inhibited osteoblast proliferation and stimulated osteoblast differentiation. We showed that FIGNL1 may play some regulatory role in osteoblastogenesis. INTRODUCTION: The fidgetin-like 1 (FIGNL1) gene encodes a new subfamily member of ATPases associated with diverse cellular activities (AAA proteins). Although the FIGNL1 protein localizes to both the nucleus and cytoplasm, the function of FIGNL1 remains unknown. In a previous study, we identified several genes that mediate the anabolic effects of basic fibroblast growth factor (bFGF) on bone by using microarray data. FIGNL1 was one of the genes that downregulated >2-fold in MC3T3-E1 cells after treatment with bFGF. Therefore, this study was aimed to identify and confirm the function of FIGNL1 on osteoblastogenesis. MATERIALS AND METHODS: We examined the effect of the FIGNL1 gene on proliferation, differentiation, and apoptosis in mouse osteoblast cells (MC3T3-E1 and mouse primary calvarial cells) using flow cytometry, RT-PCR, cell proliferation assay, and cell death assay. MC3T3-E1 cells and mouse calvarial cells were transfected with small interfering RNA (siRNA) directed against the FIGNL1 or nontargeting control siRNA and examined by cell proliferation and cell death assays. Also, FIGNL1 was fused to enhance green fluorescent protein (EGFP), and the EGFP-fused protein was transiently expressed in MC3T3-E1 cells. RESULTS: Reduced expression of FIGNL1 by bFGF and TGF-beta1 treatment was verified by RT-PCR analysis. Overexpression of FIGNL1 reduced the proliferation of MC3T3-E1 and calvarial cells, more than the mock transfected control cells did. In contrast, siFIGNL1 transfection significantly increased the proliferation of osteoblasts, whereas overexpression of FIGNL1 did not seem to alter apoptosis in osteoblasts. Meanwhile, overexpression of FIGNL1 enhanced the mRNA expression of alkaline phosphatase (ALP) and osteocalcin (OCN) in osteoblasts. In contrast, siFIGNL1 decreased the expression of ALP and OCN. A pEGFP-FIGNL1 transfected into MCT3-E1 cells had an initially ubiquitous distribution and rapidly translocated to the nucleus 1 h after bFGF treatment. CONCLUSIONS: From these results, we proposed that FIGNL1, a subfamily member of the AAA family of proteins, might play some regulatory role in osteoblast proliferation and differentiation. Further analyses of FIGNL1 will be needed to better delineate the mechanisms contributing to the inhibition of proliferation and stimulation of osteoblast differentiation.  相似文献   
2.
SUMMARY Four specialised air mattresses had interface pressure measured under six body sites prone to pressure sores in 10 subjects, supine and sitting. The mattresses were the Clinirest (SSI) and FirstStep (KCI) continuous airflow mattress overlays, and Airwave (Pegasus) and Nimbus (Huntleigh) alternating pressure air mattresses. On the mattress overlays, average supine interface pressures were 2.33 kPa (scapula), 4.15 kPa (elbow), 1.94 kPa (sacrum) and 2.79 kPa (buttock), although they were higher at the occiput (7.97 kPa) and heel (11.7 kPa). The alternating pressure air mattresses had an average minimum interface pressure close to zero for three sites, rising to 4.28 kPa under the heel. Average maximum interface pressures were 8.61 kPa (occiput), 5.21 kPa (scapula), 4.90 (elbow), 4.85 kPa (sacrum), 4.61 kPa (buttock) and 13.2 kPa (heel). No accepted scientific method exists for comparing the two types of mattress. Our data suggest a clinical benefit at the occiput and heel (supine) in using an alternating pressure air mattress and a benefit in using a continuous airflow mattress overlay at other sites.  相似文献   
3.
4.
A patient with chronic cerebral paragonimiasis began to have new motor seizures of the right face manifested by clonic contractions that occurred several hundred times a day, consistent with simple partial status epilepticus. Ictal electroencephalogram discharges started from the left frontal region and then spread to the left hemisphere with left frontal maximum. But clinical seizures were limited to the right face. The frequent partial seizures were controlled by the intravenous infusion of phenytoin. Brain magnetic resonance imaging showed multiple conglomerated round nodules with encephalomalacia in the left temporal and occipital lobes. Applying the technique of ictal-interictal single-photo emission computed tomography subtraction, the authors were able to localize the focal ictal-hyperperfusion on left precentral cortex adjacent to the lesions that correspond to the anatomical distribution of left face motor area.  相似文献   
5.
An autopsy case of disseminated HSV type 2 infection occurring in a neonate at 32 weeks' gestation, delivered by cesarean section after premature rupture of membrane of 7 days duration, is presented. Herpes simplex virus type 2 was isolated from the vesicular skin lesion. The mother and patient had specific antibody to type 2 herpes simplex virus. Patient's parents had denied any herpetic orolabial or genital lesion during or before this pregnancy. Cultures from the cervical and vaginal swabs of the mother were negative for HSV. Postmortem examination showed hepatic necrosis, skin vesicle, devastating necrotizing inflammation of the brain, chorioretinitis and interstitial pneumonitis.  相似文献   
6.
Summary Treatment of cancer of the cervical aerodigestive tract is challenging due in part to the difficulty in reestablishment of pharyngoesophageal continuity after resection of the involved tract. From May 1989 to August 1990, six patients underwent immediate reconstruction utilizing microvascular transfer of free radial forearm flaps following resection of pharyngoesophageal neoplasms. A small island flap connected to the radial vascular pedicle by fasciocutaneous branch was used to monitor the vascular condition of the hidden fabricated free forearm flap. Stricture is the most troublesome complication of esophageal reconstruction using a conventional free forearm flap. Two small triangular flaps were designed and inserted bilaterally in the distal anastomosis of both lateral esophageal walls to prevent circular contracture. The outer layer sutures were anchored to surrounding rigid structures to withstand shrinkage and circular contraction. The problem of stricture was solved by these procedures. This one-stage, easily monitored operation for pharyngoesophageal reconstruction is considered to be as useful as a free jejunal transfer.  相似文献   
7.
3-Monochloro-1,2-propanediol (MCPD) is a well-known by-product of acid-hydrolyzed soy sauce during its manufacturing process. MCPD has been reported genotoxic in vitro, and reproductive toxicity and carcinogenicity in rats. To evaluate the immunomodulatory effect of MCPD on murine splenocyte and macrophage in vitro, we investigated splenocyte blastogenesis by concanavalin A (Con A), anti-CD3, and lipopolyssacharide (LPS), the production of cytokines from splenocyte, and the activity of mouse peritoneal macrophages. There was a significant decrease in lymphocyte blastogenesis to Con A or anti-CD3 at subtoxic dose of MCPD. A significant decrease in splenocyte blastogenesis to LPS was also observed. The production level of interferon (IFN)-gamma on splenocyte culture with Con A was significantly reduced at the higher concentration than 1.0mM of MCPD. The levels of interleukin (IL)-4 and IL-10 were also decreased at high concentrations of MCPD. There was a significant decrease in production of nitric oxide (NO) by peritoneal macrophages treated with MCPD. MCPD also inhibits tumor necrosis factor (TNF)-alpha production of stimulated macrophages. These results indicate that MCPD might be able to reduce the functionality of lymphocytes and peritoneal macrophages in vitro.  相似文献   
8.
MacEwan  DW 《Radiology》1987,163(2):559-563
Eleven radiologists appointed by the major radiological societies participated for the past 5 years in the development of the Health Policy Agenda for the American People. The Agenda is an action plan to address a wide variety of serious problems in medicine. The first phase involved establishment of 159 principles, broad value statements that were the foundation of the project. Phase 2 involved the development of policy proposals on 38 urgent issues for action in medical science; education; health resources; delivery mechanisms; evaluation, assessment, and control; and payment for services. These proposals are summarized in this report. The activities and recommendations of representatives for the field of radiology are described. The Agenda has been released, and an implementation phase has begun. It will likely be of great importance to the practice of radiology over the next decade. Important issues can be addressed by acting with the coalitions that are being formed from among the more than 150 participating organizations.  相似文献   
9.
10.
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