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   39391篇
  免费   3131篇
  国内免费   1622篇
耳鼻咽喉   382篇
儿科学   520篇
妇产科学   406篇
基础医学   6461篇
口腔科学   3275篇
临床医学   4650篇
内科学   4736篇
皮肤病学   730篇
神经病学   1572篇
特种医学   1787篇
外国民族医学   8篇
外科学   6489篇
综合类   5150篇
现状与发展   11篇
预防医学   1385篇
眼科学   577篇
药学   2607篇
  13篇
中国医学   1231篇
肿瘤学   2154篇
  2023年   568篇
  2022年   688篇
  2021年   1218篇
  2020年   1333篇
  2019年   1237篇
  2018年   1335篇
  2017年   1239篇
  2016年   1316篇
  2015年   1401篇
  2014年   2583篇
  2013年   3464篇
  2012年   2186篇
  2011年   2564篇
  2010年   2011篇
  2009年   2068篇
  2008年   2163篇
  2007年   2165篇
  2006年   1939篇
  2005年   1826篇
  2004年   1586篇
  2003年   1364篇
  2002年   997篇
  2001年   897篇
  2000年   674篇
  1999年   586篇
  1998年   407篇
  1997年   377篇
  1996年   324篇
  1995年   364篇
  1994年   315篇
  1993年   241篇
  1992年   254篇
  1991年   252篇
  1990年   213篇
  1989年   193篇
  1988年   186篇
  1987年   164篇
  1986年   136篇
  1985年   186篇
  1984年   147篇
  1983年   107篇
  1982年   134篇
  1981年   144篇
  1980年   123篇
  1979年   87篇
  1978年   74篇
  1977年   57篇
  1976年   76篇
  1975年   31篇
  1972年   28篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Genetic evidence based on two-sample Mendelian randomization approaches suggested that visceral adipose tissue had a causal, independent role in lowering the risk of Parkinson's disease. Further studies are needed to explore the underlying mechanism.  相似文献   
72.
With the advance of genome engineering technology, chimeric antigen receptors (CARs)-based immunotherapy has become an emerging therapeutic strategy for tumors. Although initially designed for T cells in tumor immunotherapy, CARs have been exploited to modify the function of natural killer (NK) cells against a variety of tumors, including hepatocellular carcinoma (HCC). CAR-NK cells have the potential to sufficiently kill tumor antigen-expressing HCC cells, independent of major histocompatibility complex matching or prior priming. In this review, we summarize the recent advances in genetic engineering of CAR-NK cells against HCC and discuss the current challenges and prospects of CAR-NK cells as a revolutionary cellular immunotherapy against HCC.  相似文献   
73.
74.
75.
套管式长针属古代“九针”中“长针”的范畴,可祛深邪久痹,通过松解神经根,刺激相应区域的肌肉,以调节机体生理功能。套管式长针深层软组织松解术依据中医学经筋理论和以痛为腧理论,属于古代针刺中的“经刺”“报刺”“恢刺”及“合谷刺”等范畴。通过针刺疏散瘀滞之气血,以通治痛。套管式长针弥补普通毫针刺激量小及松解类针具风险较大的不足,兼具针刺调衡、提插松解的双重作用。套管式长针深层软组织松解术对深层肌纤维紧张所导致的各类难治性疼痛类疾病疗效明显,为临床医生提供了新的治疗方式,具有较高的推广及应用价值。  相似文献   
76.
IntroductionTo determine the diagnostic yield of repeat ultrasound (US)-guided biopsy of musculoskeletal soft-tissue lesions with initially inconclusive biopsy results, and to explore predictive factors for success of repeat biopsy.Materials and methodsThis retrospective study included 42 patients who underwent a repeat (second) US-guided biopsy session to target a musculoskeletal soft-tissue lesion because an initial US-guided biopsy session provided inconclusive results. Both biopsy sessions were performed in a tertiary referral center for soft-tissue sarcomas.ResultsThe diagnostic yield of repeat US-guided biopsy was 47.6%. Malignant nature of the lesion (P = 0.031), sharp lesion borders on US (P = 0.011), and good to very good lesion visibility on US (P = 0.017) were significantly associated with a diagnostic repeat US-guided biopsy. There was also a trend towards significance (P = 0.073) for a higher number of biopsy passes through the lesion. Other patient characteristics (age and gender), magnetic resonance imaging features (lesion homogeneity on T1-weighted, T2-weighted, and gadolinium chelate enhanced sequences, borders, enhancement pattern, depth and size), US features (lesion appearance, vascular flow, and depth), biopsy-related factors (days between initial and repeat US-guided biopsy, needle diameter, maximum length of acquired samples), and operator-related factors (same or different radiologists/pathologists for initial and repeat biopsies), were not associated with the diagnostic success of the repeat US-guided biopsy.ConclusionsRepeat US-guided biopsy of a musculoskeletal soft-tissue lesion with initially inconclusive biopsy results can be useful to establish a final diagnosis. Lesion features on US (borders and visibility) may be used to prospectively determine the utility of a repeat US-guided biopsy.  相似文献   
77.
目的:利用代谢组学技术分析慢性温和不可预知应激(CUMS)抑郁模型小鼠脑组织样本,寻找与抑郁相关的差异代谢物,探讨蜘蛛香环烯醚萜部位(IEFV)可能的抗抑郁作用机制。方法:42只昆明小鼠随机分为6组,包括正常组,模型组,氟西汀组(2.5 mg·kg-1),IEFV低、中、高剂量组(给药剂量分别为5.73,11.47,22.94 mg·kg-1)。采用CUMS对小鼠造模,以IEFV及阳性药(氟西汀)为干预药物,用行为指标和生化指标进行药效学评价。采用核磁共振氢谱(1H-NMR)代谢组学技术分析IEFV对CUMS抑郁模型小鼠脑组织中内源性物质的影响,结合多变量统计分析方法来确认差异代谢物,并对差异代谢物参与的代谢通路进行富集。结果:造模后,小鼠的不动时间大幅度提高、蔗糖偏好率明显下降,兴奋性神经递质5-羟色胺和去甲肾上腺素显著下降,表明造模成功。给予IEFV和氟西汀后,小鼠不动时间、蔗糖偏好率和兴奋性神经递质向正常水平回调,提示给药后抑郁状态得到了一定程度的缓解。脑组织中内源性代谢物主成分分析(PCA)结果显示,模型组可与正常组明显分开,同时IEFV低、中、高剂量组和氟西汀组均显示有偏离模型组向正常组靠拢的趋势,与行为学结果一致。模型组与正常组进行正交偏最小二乘法-判别分析(OPLS-DA)得到了16个变化显著的差异代谢物,包括12个水溶性差异代谢物和4个脂溶性差异代谢物。通过MetPA数据库分析得到7条潜在靶标代谢通路,包括三羧酸循环(TCA),牛磺酸和亚牛磺酸的代谢,丙氨酸、天冬氨酸和谷氨酸代谢等。IEFV高剂量组可显著回调11种差异代谢物。结论:IEFV可能主要通过影响能量代谢,氨基酸代谢和神经递质水平发挥抗抑郁作用,可为IEFV抗抑郁作用机制的深入研究提供参考依据。  相似文献   
78.
《The Journal of arthroplasty》2020,35(12):3686-3691
BackgroundTreatment of adverse local tissue reaction (ALTR) is challenging owing to high complications and poor outcomes after a revision surgery. As dislocation is the most common cause of reoperation, it is often necessary to use advanced articulations such as dual mobility. This study aims to evaluate the outcome and complication rates after revision surgery with dual mobility constructs, compared to constrained and conventional articulations in the setting of significant abductor deficiency due to ALTR.MethodsOut of a total of 338 revision total hip arthroplasties for ALTR, 234 patients with a significant tissue necrosis and abductor muscle insufficiency (grade 3) were evaluated. The complication rates after revisions were compared between 42 hips with dual mobility implants, 24 hips with constrained liners, 104 hips with large diameter heads (36-40 mm), and 64 hips with small diameter heads (≤32 mm).ResultsAfter an average of 4 years of follow-up (2.8-8.6), the dual mobility articulation had no dislocation, compared to 4.1% and 15.5% for constrained liner and conventional articulations, respectively (P < .001). Utilization of dual mobility and constrained liner cup also did not increase the risk of nondislocation complications, including periprosthetic joint infection and periprosthetic fracture (P = .18 and .52).ConclusionsThis study demonstrates significantly lower dislocation rates for dual mobility when compared to conventional articulations and comparable to constrained liners in cases of severe abductor deficiency due to ALTR, suggesting that dual mobility implants are viable surgical treatment alternatives to constrained liners to minimize dislocation during revision total hip arthroplasty in the setting of significant abductor deficiency due to ALTR.  相似文献   
79.
The regulation of food intake is a complex mechanism, and the hypothalamus is the main central structure implicated. In particular, the arcuate nucleus appears to be the most critical area in the integration of multiple peripheral signals.Among these signals, those originating from the white adipose tissue and the gastrointestinal tract are known to be involved in the regulation of food intake.The present paper focuses on adiponectin, an adipokine secreted by white adipose tissue, which is reported to have a role in the control of feeding by acting centrally. The recent observation that adiponectin is also able to influence gastric motility raises the question of whether this action represents an additional peripheral mechanism that concurs with the central effects of the hormone on food intake. This possibility, which represents an emerging aspect correlating the central and peripheral effects of adiponectin in the hunger-satiety cycle, is discussed in the present paper.  相似文献   
80.
An intricate problem during open human fetal surgery for spina bifida regards back skin closure, particularly in those cases where the skin defect is much too large for primary closure. We hypothesize that tissue engineering of fetal skin might provide an adequate autologous skin substitute for in utero application in such situations. Eight sheep fetuses of four time‐mated ewes underwent fetoscopic skin biopsy at 65 days of gestation. Fibroblasts and keratinocytes isolated from the biopsy were used to create fetal dermo‐epidermal skin substitutes. These were transplanted on the fetuses by open fetal surgery at 90 days of gestation on skin defects (excisional wounds) created during the same procedure. Pregnancy was allowed to continue until euthanasia at 120 days of gestation. The graft area was analyzed macroscopically and microscopically. The transplanted fetal dermo‐epidermal skin substitutes was well discernable in situ in three of the four fetuses available for analysis. Histology confirmed healed grafts with a close to natural histological skin architecture four weeks after in utero transplantation. This experimental study generates evidence that laboratory grown autologous fetal skin analogues can successfully be transplanted in utero. These results have clinical implications as an analogous procedure might be applied in human fetuses undergoing prenatal repair to facilitate primary skin closure. Finally, this study may also fertilize the field of fetal tissue engineering in general, particularly when more interventional, minimally invasive, and open fetal surgical procedures become available.  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