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   101390篇
  免费   5544篇
  国内免费   266篇
耳鼻咽喉   1310篇
儿科学   2408篇
妇产科学   2195篇
基础医学   14204篇
口腔科学   3287篇
临床医学   8095篇
内科学   23582篇
皮肤病学   2428篇
神经病学   9283篇
特种医学   2997篇
外国民族医学   10篇
外科学   13779篇
综合类   494篇
一般理论   38篇
预防医学   8462篇
眼科学   2056篇
药学   6754篇
中国医学   350篇
肿瘤学   5468篇
  2023年   610篇
  2022年   432篇
  2021年   1578篇
  2020年   990篇
  2019年   1624篇
  2018年   2837篇
  2017年   1794篇
  2016年   1985篇
  2015年   2665篇
  2014年   2824篇
  2013年   4014篇
  2012年   7799篇
  2011年   7906篇
  2010年   3626篇
  2009年   2782篇
  2008年   6710篇
  2007年   6921篇
  2006年   7060篇
  2005年   6764篇
  2004年   6163篇
  2003年   5592篇
  2002年   5365篇
  2001年   2470篇
  2000年   2910篇
  1999年   1774篇
  1998年   519篇
  1997年   399篇
  1996年   368篇
  1995年   352篇
  1994年   281篇
  1993年   289篇
  1992年   587篇
  1991年   551篇
  1990年   551篇
  1989年   493篇
  1988年   432篇
  1987年   477篇
  1986年   453篇
  1985年   447篇
  1984年   384篇
  1983年   291篇
  1982年   244篇
  1980年   221篇
  1979年   314篇
  1978年   259篇
  1977年   225篇
  1974年   234篇
  1973年   230篇
  1972年   234篇
  1971年   222篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Intraosseous neurilemmoma of the radius: a case report   总被引:2,自引:0,他引:2  
Neurilemmomas are benign tumors that arise from Schwann cells. They are rarely found on bone. We describe a neurilemmoma in a 45-year-old patient that affected the distal metaphysis of the radius. Only 1 previous case has been described in the literature. We discuss the clinical presentation, the radiographic aspect, particularly the magnetic resonance imaging characteristics, and the microscopic findings.  相似文献   
992.
993.
The Authors report a case of rupture of the diaphragm in blunt trauma of the abdomen, to examine the more significant features of this condition whose incidence proves to be increasing, after a review of the literature data, parallel to the increase of accidents on the road and at work. They examine the most important pathogenic problems and these related to the mechanism leading to diaphragmatic lesion and they highlight the deeper pathophysiological changes suffered from the patient with such a condition. They draw attention to what they consider to be the most important aspect, and therefore the diagnosis. In fact, in accordance with the various series of cases reported in the literature, it is crucial in the diagnostic problem is when the possible cause of the rupture is suspected and necessary diagnostic cascade (Rx, echotomography, TC) is activated so to highlight the lesion. Therefore a quick diagnostic fitting is necessary for the survival of the acute patient with hernia of the thorax cavity, as well as quick surgical correction of the lesion that, as in the case described, serves to achieve the best possible anatomic-functional results.  相似文献   
994.
We report a case of chronic instability due to rupture of the ulnar collateral ligament of the metacarpophalangeal joint of the index finger of the left hand. Because of persistent instability after the initial conservative treatment, surgical treatment was required.  相似文献   
995.
STUDY DESIGN: Clinical evaluation of the Parastep method, a six-channel transcutaneous functional electrical stimulation device, in spinal cord-injured patients. OBJECTIVES: To investigate the motor performances of this new technique regarding energy expenditure and to evaluate its advantages and limitations, especially in social activities involving ambulation. METHODS: This study was conducted in 15 thoracic spine-injured patients. The lesion was complete except in two patients. The gait ability and the functional use were judged clinically. Energy cost was evaluated from heart rate, peak oxygen uptake, and lactatemia. RESULTS: Thirteen patients completed the training (mean: 20 sessions) and achieved independent ambulation with a walker. The mean walking distance, without rest, was 52.8 +/- 69 m, and the mean speed was 0.15 +/- 0.14 m/sec. One patient with incomplete lesion, who had been nonambulatory for 8 months after the injury, became able to walk without functional electrical stimulation after five sessions. The follow-up was 40 +/- 11 months. Five patients pursued using functional electrical stimulation-assisted gait as a means of physical exercise but not for ambulation in social activities. The patients experienced marked psychological benefits, with positive changes in their way of life. In three subjects, a comparison of physiologic responses to exercise between a progressive arm ergometer test and a walking test with the Parastep (Sigmedics, Inc., Northfield, IL) at a speed of 0.1 m/sec was performed, showing that the heart rate, the peak oxygen uptake, and lactatemia during gait were close to those obtained at the end of the maximal test on the ergometer. CONCLUSIONS: In spite of its ease of operation and good cosmetic acceptance, the Parastep approach has very limited applications for mobility in daily life, because of its modest performance associated with high metabolic cost and cardiovascular strain. However, it can be proposed as a resource to keep physical and psychological fitness in patients with spinal cord injury.  相似文献   
996.
997.
BACKGROUND: Chronic prostatic pain is still a diagnostic and therapeutic problem. The clinical observation that prostatic and pelvic pain is accompanied by motoric and sensoric disorders of the pelvic floor muscles led to the hypothesis that prostatic pain roots in a changed processing of afferent and efferent information with the central nervous system (CNS). METHODS: Neuro-urological work-up of 11 male patients with chronic prostatic pain was completed. This included a clinical evaluation of pelvic floor function, urodynamic investigation of bladder and urethra function and a cystoscopy to exclude morphological aberrations. A transurethral perisphincteric injection of 200 units botulinum toxin type A (BTX) was followed by a 2- to 4-week visit to evaluate their influence on the neuro-urological symptomatology. RESULTS: All chronic prostatic pain patients suffered from a pathological pelvic floor tenderness, an inability of sufficient conscious pelvic floor control, a urethral hypersensitivity/hyperalgesia and a urethral muscle hyperactivity. Basic parameters of bladder function (capacity, sensitivity, compliance) were normal. The BTX injection was followed by a pelvic floor muscle weakening and a relief of prostatic pain and urethral hypersensitivity/hyperalgesia. A botulinum-related decrease of the functional urethral length, the urethral sphincter closure pressure, the postvoid residual volume and an increase of the peak and average uroflow were objectivated. CONCLUSION: A weakening of the urethral sphincter muscle via blocking acetylcholine release by BTX injection is followed by pain relief and symptom improvement. It can therefore be concluded that a barrage of nociceptive information from the dysfunctional pelvic floor overflood the CNS and induce a changed CNS processing. Interrupting the efferent branch of the disturbed central circle is one opportunity to treat chronic prostatic pain.  相似文献   
998.
Toxins from cone snail (Conus species) venoms are multiple disulfide bonded peptides. Based on their pharmacological target (ion channels, receptors) and their disulfide pattern, they have been classified into several toxin families and superfamilies. Here, we report a new conotoxin, which is the first member of a structurally new superfamily of Conus peptides and the first conotoxin affecting vertebrate K+ channels. The new toxin, designated conotoxin ViTx, has been isolated from the venom of Conus virgo and comprises a single chain of 35 amino acids cross-linked by four disulfide bridges. Its amino acid sequence (SRCFPPGIYCTSYLPCCWGICCSTCRNVCHLRIGK) was partially determined by Edman degradation and deduced from the nucleotide sequence of the toxin cDNA. Nucleic acid sequencing also revealed a prepropeptide comprising 67 amino acid residues and demonstrated a posttranslational modification of the protein by releasing a six-residue peptide from the C-terminal. Voltage clamp studies on various ion channels indicated that the toxin inhibits the vertebrate K+ channels Kv1.1 and Kv1.3 but not Kv1.2. The chemically synthesized product exhibited the same physiological activity and identical molecular mass (3933.7 Da) as the native toxin.  相似文献   
999.
SSR181507 ((3-exo)-8-benzoyl-N-[[(2S)7-chloro-2,3-dihydro-1,4-benzodioxin-1-yl]methyl]-8-azabicyclo[3.2.1]octane-3-methanamine monohydrochloride) is a novel tropanemethanamine benzodioxane derivative that possesses high and selective affinities for D2-like and 5-HT(1A) receptors (K(I)=0.8, 0.2, and 0.2 nM for human D(2), D(3), and 5-HT(1A), respectively). In vivo, SSR181507 inhibited [(3)H]raclopride binding to D(2) receptors in the rat (ID(50)=0.9 and 1 mg/kg, i.p. in limbic system and striatum, respectively). It displayed D(2) antagonist and 5-HT(1A) agonist properties in the same concentration range in vitro (IC(50)=5.3 nM and EC(50)=2.3 nM, respectively, in the GTPgammaS model) and in the same dose range in vivo (ED(50)=1.6 and 0.7 mg/kg, i.p. on striatal DA and 5-HT synthesis, respectively, and 0.03-0.3 mg/kg, i.v. on dorsal raphe nucleus firing rate). It selectively enhanced Fos immunoreactivity in mesocorticolimbic areas as compared to the striatum. This regional selectivity was confirmed in electrophysiological studies where SSR181507, given acutely (0.1-3 mg/kg, i.p.) or chronically (3 mg/kg, i.p., o.d., 22 days), increased or decreased, respectively, the number of spontaneous active DA cells in the ventral tegmental area, but not in the substantia nigra. Moreover, SSR181507 increased both basal and phasic DA efflux (as assessed by microdialysis and electrochemistry) in the medial prefrontal cortex and nucleus accumbens, but not in the striatum. This study shows that the combination of D(2) receptor antagonism and 5-HT(1A) agonism, in the same dose range, confers on SSR181507 a unique neurochemical and electrophysiological profile and suggests the potential of this compound for the treatment of the main dimensions of schizophrenia.  相似文献   
1000.
A 36-year old woman was bitten on the left ankle by a Bothrops jararacussu, and died 45 min after the bite. At necropsy, there were local signs of envenoming with haemorrhage, thrombosis and necrosis of the subcutaneous and muscular tissue. Multiple fibrin and platelet thrombi were found in the microcirculation of the heart and lungs, suggesting the occurrence of disseminated intravascular coagulation. Pulmonary haemorrhage probably secondary to the action of haemorrhagins, consumption coagulopathy and disseminated intravascular coagulation was the immediate cause of death. Intravenous inoculation of the venom could have occurred in the present case, which would explain the rapid onset of coagulation disorders, haemorrhage and death.  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