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   3950篇
  免费   287篇
  国内免费   15篇
耳鼻咽喉   15篇
儿科学   113篇
妇产科学   53篇
基础医学   451篇
口腔科学   46篇
临床医学   512篇
内科学   966篇
皮肤病学   124篇
神经病学   393篇
特种医学   132篇
外科学   933篇
综合类   26篇
预防医学   163篇
眼科学   43篇
药学   160篇
中国医学   5篇
肿瘤学   117篇
  2023年   26篇
  2022年   35篇
  2021年   84篇
  2020年   51篇
  2019年   92篇
  2018年   112篇
  2017年   78篇
  2016年   96篇
  2015年   77篇
  2014年   118篇
  2013年   144篇
  2012年   173篇
  2011年   205篇
  2010年   175篇
  2009年   192篇
  2008年   216篇
  2007年   213篇
  2006年   246篇
  2005年   229篇
  2004年   214篇
  2003年   187篇
  2002年   176篇
  2001年   106篇
  2000年   117篇
  1999年   100篇
  1998年   71篇
  1997年   55篇
  1996年   58篇
  1995年   48篇
  1994年   45篇
  1993年   45篇
  1992年   64篇
  1991年   57篇
  1990年   50篇
  1989年   48篇
  1988年   36篇
  1987年   46篇
  1986年   29篇
  1985年   18篇
  1984年   15篇
  1983年   11篇
  1981年   11篇
  1980年   6篇
  1979年   7篇
  1978年   9篇
  1977年   9篇
  1976年   8篇
  1975年   6篇
  1973年   8篇
  1971年   7篇
排序方式: 共有4252条查询结果,搜索用时 11 毫秒
101.
Bending the rule of monotherapy for migraine prevention?   总被引:1,自引:0,他引:1  
Evans RW  Pascual J  Láinez MJ  Leira R 《Headache》2005,45(6):748-750
  相似文献   
102.
Pseudomigraine with temporary neurologic symptoms and lymphocytic pleocytosis is a self-limited syndrome of unknown origin characterized by headache accompanied by transient neurologic symptoms and cerebrospinal fluid lymphocytosis. Patients with this condition are between 15 and 40 years of age. The syndrome is more frequent in men. The clinical picture encompasses one to 12 episodes of changing variable neurologic deficits accompanied by moderate to severe headache and occasional fever. These headaches are described as predominantly throbbing and bilateral with a variable duration (mean, 19 hours). The average duration of the transient neurologic deficit is 5 hours. Sensory (78% episodes), aphasic (66%), and motor (56%) disturbances are the most common. Migraine-like visual symptoms are relatively rare (18% episodes). Patients are asymptomatic between episodes and after the symptomatic period (duration > 3 months). Lymphocytic pleocytosis (10 to 760 cells mm3) and increased cerebrospinal fluid protein are found with negative bacteriologic, viral, fungal, and immunologic studies. Brain computed tomography and magnetic resonance imaging are normal, but an electroencephalogram frequently shows focal slowing over the symptomatic brain area. Single photon emission computed tomography reveals transient focal areas of decreased uptake consistent with the clinical symptoms. It is possible that pseudomigraine with temporary neurologic symptoms and lymphocytic pleocytosis could result from an activation of the immune system secondary to a recent viral infection, which would produce antibodies against neuronal or vascular antigens. This autoimmune attack may induce an aseptic leptomeningeal vasculitis, accounting for the headache and the transient symptoms likely through a spreading depression-like mechanism.  相似文献   
103.
The agar dilution, broth microdilution, and disk diffusion methods were compared to determine the in vitro susceptibility of 428 extended-spectrum-beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae to fosfomycin. Fosfomycin showed very high activity against all ESBL-producing strains. Excellent agreement between the three susceptibility methods was found for E. coli, whereas marked discrepancies were observed for K. pneumoniae.  相似文献   
104.
The effects of 17-alpha-estradiol on the secretion of catecholamines from the perfused bovine and cat adrenal gland and bovine chromaffin cells in culture elicited by dimethylphenylpiperazinium (DMPP), methacholine and high potassium were studied. In perfused cat adrenal glands, secretion of catecholamines evoked by pulses of DMPP (1 microM for 30 sec) was decreased by 17-alpha-estradiol at concentrations of 1 and 10 microM by 50 and 80%, respectively. However, secretion evoked by pulses of methacholine (3 microM for 30 sec) was not affected by 1 microM of 17-alpha-estradiol and was affected to a variable extent by 10 microM 17-alpha-estradiol. Catecholamine secretion evoked by higher concentrations of methacholine (100 microM for 60 sec) was reduced by 50% by 10 microM 17-alpha-estradiol. 17-alpha-Estradiol decreased secretion evoked by pulses of 120 mM K+ for 10 sec to a similar extent in the perfused bovine and cat adrenal gland. The 45Ca++ uptake into bovine chromaffin cells in culture stimulated by DMPP (100 microM for 10 sec) or high K+ (59 mM for 10 sec) was almost inhibited completely by 100 microM 17-alpha-estradiol. The rapid action precludes a classical genomic mechanism and suggests effects at the cell membrane.  相似文献   
105.
A total of 192 pediatric patients, median age 8.6 years, with high-risk hematological malignancies, underwent haploidentical stem cell transplantation (haplo-HSCT) using post-transplantation cyclophosphamide (PT-Cy), or ex vivo T cell-depleted (TCD) graft platforms, from January 1999 to December 2016 in 10 centers in Spain. Some 41 patients received an unmanipulated graft followed by PT-Cy for graft-vs-host disease (GvHD) prophylaxis. A total of 151 patients were transplanted with CD3-depleted peripheral blood stem cells (PBSCs) by either CD34+ selection, CD3+CD19+ depletion, TCRαβ+CD19+ depletion or CD45RA+ depletion, added to CD34+ selection for GvHD prophylaxis. The PBSCs were the only source in patients following ex vivo TCD haplo-HSCT; bone marrow was the source in 9 of 41 patients following PT-CY haplo-HSCT. Engraftment was achieved in 91.3% of cases. A donor younger than 30 years, and the development of chronic GvHD were positive factors influencing survival, whereas positive minimal residual disease (MRD) before transplant and lymphoid disease were negative factors. The probability of relapse increased with lymphoid malignancies, a donor killer-cell immunoglobulin-like receptor (KIR) haplotype A and positive MRD pretransplant. No difference was found in overall survival, disease-free survival or relapse incidence between the two platforms. Relapse is still of concern in both platforms, and it should be the focus of future efforts. In conclusion, both platforms for haplo-HSCT were effective and could be utilized depending on the comfort level of the center.  相似文献   
106.
目的:流行病学调查结果显示,地方性氟中毒与甲状腺肿的流行有很大的重叠性。探讨氟化钠对原代培养猪甲状腺细胞及甲状腺过氧化物酶活性的影响。方法:实验于2006-10/2007-05在辽宁医学院科学实验室中心完成。①实验方法:在猪死亡1h内取其甲状腺组织,去除甲状腺组织包膜及外层活性差的组织,选取中央活性高的部位,剪成1mm3组织块,用胰蛋白酶、胶原酶Ⅳ消化分离,得到含猪甲状腺细胞的消化液,沉淀悬于含体积分数为0.15的胎牛血清、1U/L牛促甲状腺素、80万U/L庆大霉素的F12培养基中,过滤,调整细胞浓度至5×105L-1,接种培养,每3d更换培养液。常规培养48h的猪甲状腺细胞接种于96孔培养板,按氟化钠终浓度不同分为0,40,80,160mg/L组。②实验评估:染毒48h后,采用噻唑蓝法测定细胞存活量,采用改良愈创木酚法测定甲状腺过氧化物酶活性。结果:①氟化钠对原代培养猪甲状腺细胞存活量的影响:与0mg/L氟化钠比较,40mg/L氟化钠染毒后猪甲状腺细胞的存活量基本相似;80,160mg/L氟化钠染毒后猪甲状腺细胞的存活量均明显下降(P<0.01)。②氟化钠对甲状腺过氧化物酶活性的影响:与0mg/L氟化钠比较,40,80,160mg/L氟化钠染毒后的甲状腺过氧化物酶活性均明显下降(P<0.01),呈剂量-效应关系。结论:氟化钠对原代培养的猪甲状腺细胞及甲状腺过氧化物酶活性均具有抑制作用。  相似文献   
107.
Paclitaxel is an effective antineoplastic drug treatment used as an anti-tumoral therapy. Unfortunately its use is associated with unwanted side effects, which include the development of peripheral neuropathies and neuropathic pain, greatly affecting the quality of life of patients. It is well known that agonists of the cannabinoid receptor are able to reduce hyperalgesia and allodynia that develop after nerve injury. Our aim was to evaluate the efficacy of the cannabinoid agonist WIN 55,212-2 to reduce the thermal hyperalgesia and the tactile allodynia induced by administration of paclitaxel in rats. Present results demonstrate that WIN 55,212-2 (1 mg/kg i.p.) significantly reduced the heat (P<0.0001) and the mechanical (P=0.0003) withdrawal thresholds, the dose being smaller than that required to reach similar effects in the sciatic nerve constriction model (1.5 mg/kg). When the cannabinoid tetrad test was evaluated to measure behavioral modifications, it was found that WIN 55,212-2 (1mg/kg) did not induce changes either in body temperature or in immobility time, and only a reduction in spontaneous motility was recorded. This effect was antagonized by SR 141716A, suggesting the involvement of the CB1 receptor, although the participation of CB2 receptors cannot be excluded from this study. When WIN 55,212-2 was administered intraplantar, no differences were observed between the injected paw and the contralateral paw, suggesting that systemic mechanisms are needed to reach effectiveness. From these results we suggest that cannabinoids may be an interesting alternative to reduce neuropathic symptoms induced by paclitaxel, however more work is required to assess this possibility.  相似文献   
108.
The intracellular penetration and activity of gemifloxacin in human polymorphonuclear leukocytes (PMN) were evaluated. Gemifloxacin reached intracellular concentrations eight times higher than extracellular concentrations. The uptake was rapid, reversible, and nonsaturable and was affected by environmental temperature, cell viability, and membrane stimuli. At therapeutic extracellular concentrations, gemifloxacin showed intracellular activity against Staphylococcus aureus.  相似文献   
109.
110.
HELLP syndrome (HS) occurs in 0.5-0.9% of pregnant women. According to the Tennessee criteria, it is characterised by haemolytic anaemia, thrombopenia and multi-organ dysfunction. The purpose of this article is to present the cases of four pregnant women diagnosed with HS with severe liver involvement. PATIENTS AND METHOD: We present the cases of 4 pregnant women of 24, 27, 28 and 36 weeks gestation, respectively. Pregnancy was terminated by urgent Caesarean section in all 4 cases. The first case required a right hepatectomy, with a good post-operative outcome; the second patient developed fulminant liver failure, dying due to multi-organ failure while waiting for a liver transplant. The third patient progressed satisfactorily with conservative medical treatment. The fourth patient required two livers transplants, being discharged from hospital three months later. CONCLUSIONS: When faced with the clinical suspicion of a HS it is essential to rule out a liver haematoma, since the treatment of choice depends on its clinical-radiological severity. If there is a rupture of the haematoma, urgent surgery is essential and, in the case of severe liver failure, a liver transplant is indicated.  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