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   3592篇
  免费   214篇
  国内免费   13篇
耳鼻咽喉   34篇
儿科学   76篇
妇产科学   56篇
基础医学   506篇
口腔科学   24篇
临床医学   423篇
内科学   818篇
皮肤病学   87篇
神经病学   406篇
特种医学   114篇
外国民族医学   1篇
外科学   462篇
综合类   10篇
预防医学   204篇
眼科学   50篇
药学   235篇
中国医学   5篇
肿瘤学   308篇
  2024年   5篇
  2023年   19篇
  2022年   43篇
  2021年   102篇
  2020年   59篇
  2019年   108篇
  2018年   113篇
  2017年   66篇
  2016年   71篇
  2015年   86篇
  2014年   142篇
  2013年   172篇
  2012年   271篇
  2011年   299篇
  2010年   146篇
  2009年   145篇
  2008年   231篇
  2007年   224篇
  2006年   192篇
  2005年   221篇
  2004年   202篇
  2003年   184篇
  2002年   188篇
  2001年   58篇
  2000年   52篇
  1999年   53篇
  1998年   35篇
  1997年   22篇
  1996年   16篇
  1995年   25篇
  1994年   11篇
  1993年   12篇
  1992年   21篇
  1991年   21篇
  1990年   16篇
  1989年   19篇
  1988年   8篇
  1987年   18篇
  1986年   17篇
  1985年   11篇
  1984年   9篇
  1983年   13篇
  1980年   5篇
  1979年   7篇
  1977年   9篇
  1976年   10篇
  1974年   6篇
  1971年   9篇
  1970年   9篇
  1965年   5篇
排序方式: 共有3819条查询结果,搜索用时 15 毫秒
31.
ContextMost renal cell carcinomas today are diagnosed incidentally at an early stage as small renal masses. Partial nephrectomy (PN) has become an established curative treatment in these indications and is mainly performed through open surgery.ObjectiveLaparoscopic PN (LPN) is an attractive alternative to open PN (OPN). In this article are reviewed the indications, the surgical specificities, and different options for standardisation and optimisation of LPN.Evidence acquisitionLPN should duplicate the principles of open surgery to get the same oncologic and complication outcomes. This is the case in experienced hands.Evidence synthesisThe role of LPN is, to date, restricted to high-volume laparoscopic centres. Indications should be adapted to each surgeon experience, keeping in mind that the goal of LPN is to safely remove a tumour with the lowest renal and surgical complications in a limited operative time to keep the warm ischemia time to <30 min. Surgical improvements and robot-assisted laparoscopy are two major aspects of the future development of LPN.ConclusionsLPN is a demanding surgical procedure and is so far limited to some specialised centres. New developments will potentially allow a wider use of this minimally invasive procedure.  相似文献   
32.
We conducted a micro‐CT analysis of subchondral bone of the vertebral end‐plates after application of compressive stress. Thoracic and lumbar vertebral units were instrumented by carrying out left asymmetric tether in eleven 4‐week‐old pigs. After 3 months of growth, instrumented units and control units were harvested. Micro‐CT study of subchondral bone was performed on one central and two lateral specimens (fixated side and non‐fixated side). In control units, bone volume fraction (BV/TV), number of trabeculae (Tb.N), trabecular thickness (Tb.Th), and degree of anisotropy (DA) were significantly higher, whereas intertrabecular space (Tb.Sp) was significantly lower in center than in periphery. No significant difference between the fixated and non‐fixated sides was found. In instrumented units, BV/TV, Tb.N, Tb.Th, and DA were significantly higher in center than in periphery. BV/TV, Tb.N, and Conn.D were significantly higher in fixated than in non‐fixated side, while Tb.Sp was significantly lower. We noted BV/TV, Tb.N, and Tb.Th significantly lower, and Tb.Sp significantly higher, in the instrumented levels. This study showed, in instrumented units, two opposing processes generating a reorganization of the trabecular network. First, an osteolytic process (decrease in BV/TV, Tb.N, Tb.Th) by stress‐shielding, greater in center and on non‐fixated side. Second, an osteogenic process (higher BV/TV, Tb.N, Conn.D, and lower Tb.Sp) due to the compressive loading induced by growth on the fixated side. This study demonstrates the densification of the trabecular bone tissue of the vertebral end‐plates after compressive loading, and illustrates the potential risks of excessively rigid spinal instrumentation which may induce premature osteopenia. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:232–240, 2010  相似文献   
33.
Controlled donation after circulatory death (cDCD) is used for “extended criteria” donors with poorer kidney transplant outcomes. The French cDCD program started in 2015 and is characterized by normothermic regional perfusion, hypothermic machine perfusion, and short cold ischemia time. We compared the outcomes of kidney transplantation from cDCD and brain-dead (DBD) donors, matching cDCD and DBD kidney transplants by propensity scoring for donor and recipient characteristics. The matching process retained 442 of 499 cDCD and 809 of 6185 DBD transplantations. The DGF rate was 20% in cDCD recipients compared with 28% in DBD recipients (adjusted relative risk [aRR], 1.43; 95% confidence interval [CI] 1.12–1.82). When DBD transplants were ranked by cold ischemia time and machine perfusion use and compared with cDCD transplants, the aRR of DGF was higher for DBD transplants without machine perfusion, regardless of the cold ischemia time (aRR with cold ischemia time <18 h, 1.57; 95% CI 1.20–2.03, vs aRR with cold ischemia time ≥18 h, 1.79; 95% CI 1.31–2.44). The 1-year graft survival rate was similar in both groups. Early outcome was better for kidney transplants from cDCD than from matched DBD transplants with this French protocol.  相似文献   
34.
PURPOSE OF REVIEW: As all new treatment modalities nonablative thermal therapy for minimal invasive treatment of benign prostatic hyperplasia should be critically analyzed. This review discusses the literature to identify the merits of these so-called minimally invasive treatments and the place they should take in the armamentarium of benign prostatic hyperplasia therapy options. RECENT FINDINGS: In this review we analyze the different techniques and clinical studies of hot water induced thermotherapy, transurethral microwave thermotherapy, transurethral needle ablation and high intensity focused ultrasound. The high intensity focused ultrasound treatment is noninvasive, but due to the poor clinical results in benign prostatic hyperplasia and its need for anesthesia, this therapeutic option shifted towards the selective ablation of prostate cancer. The transurethral needle ablation treatment can be performed in an outpatient setting although most centers do not. The treatment is not suitable for the bigger prostates and therefore narrows its indication. Water induced thermotherapy is a very promising therapy, although without comparative studies a justified positioning remains difficult. SUMMARY: Of all nonablative thermal therapies, transurethral microwave thermotherapy is the best documented and with several randomized studies comparing transurethral microwave thermotherapy to surgical treatments of the prostate, this therapy definitively found its place as a serious alternative to the ablative surgical treatment options.  相似文献   
35.
36.

Background:

Olfactory bulbectomized rats generally manifest many of the neurochemical, physiological, and behavioral features of major depressive disorder in humans. Another interesting feature of this model is that it responds to chronic but not acute antidepressant treatments, including selective serotonin reuptake inhibitors. The purpose of the present study was first to characterize the firing activity of dorsal raphe serotonin neurons in olfactory bulbectomized rats and then examine the effects of 2 antidepressants, bupropion and paroxetine.

Methods:

Olfactory bulbectomy was performed by aspirating olfactory bulbs in anesthetized rats. Vehicle and drugs were delivered for 2 and 14 days via subcutaneously implanted minipumps. In vivo electrophysiological recordings were carried out in male anesthetized Sprague-Dawley rats.

Results:

Following ablation of olfactory bulbs, the firing rate of serotonin neurons was decreased by 36%, leaving those of norepinephrine and dopamine neurons unchanged. In olfactory bulbectomized rats, bupropion (30mg/kg/d) restored the firing rate of serotonin neurons to the control level following 2- and 14-day administration and also induced an increase in the tonic activation of serotonin1A receptors; paroxetine (10mg/kg/d) did not result in a return to normal of the attenuated firing of serotonin neurons in olfactory bulbectomized rats. In the hippocampus, although at a higher dose of WAY 100635 than that required in bupropion-treated animals, paroxetine administration also resulted in an increase in the tonic activation of serotonin1A receptors.

Conclusions:

The present results indicate that unlike paroxetine, bupropion administration normalized serotonin neuronal activity and increased tonic activation of the serotonin1A receptors in hippocampus.  相似文献   
37.
In humans, type I interferon (IFN) is a family of 17 cytokines, among which the alpha subtypes and the beta subtype are differentially expressed. It has been suggested that IFN-beta activates a specific signaling cascade in addition to those activated by all type I IFNs. Nevertheless, no true biological relevance for a differential activity of alpha and beta IFN subtypes has been identified so far. Because type I IFNs are critical for the regulation of osteoclastogenesis in mice, we have compared the effect of IFN-alpha2 and IFN-beta on the differentiation of human monocytes into osteoclasts. Primary monocytes undergoing osteoclastic differentiation are highly and equally sensitive to both alpha2 and beta IFNs as determined by measuring the induction levels of several IFN-stimulated genes. However, IFN-beta was 100-fold more potent than the alpha2 subtype at inhibiting osteoclastogenesis. Expression profiling of the genes differentially regulated by IFN-alpha2 and IFN-beta in this cellular system revealed the chemokine CXCL11 as the only IFN-induced gene differentially up-regulated by IFN-beta. We show that recombinant CXCL11 by itself inhibits osteoclastic differentiation. These results indicate that autocrine-acting CXCL11 mediates, at least in part, the regulations of osteoclastogenesis by type I IFNs.  相似文献   
38.
39.
40.
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