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   729篇
  免费   27篇
  国内免费   97篇
耳鼻咽喉   6篇
儿科学   64篇
妇产科学   1篇
基础医学   62篇
口腔科学   20篇
临床医学   109篇
内科学   208篇
皮肤病学   7篇
神经病学   21篇
特种医学   111篇
外科学   45篇
综合类   37篇
预防医学   45篇
眼科学   4篇
药学   86篇
肿瘤学   27篇
  2023年   3篇
  2022年   2篇
  2021年   6篇
  2020年   2篇
  2019年   6篇
  2018年   4篇
  2017年   4篇
  2016年   6篇
  2015年   7篇
  2014年   10篇
  2013年   24篇
  2012年   15篇
  2011年   14篇
  2010年   28篇
  2009年   26篇
  2008年   19篇
  2007年   62篇
  2006年   25篇
  2005年   29篇
  2004年   11篇
  2003年   7篇
  2002年   16篇
  2001年   28篇
  2000年   20篇
  1999年   24篇
  1998年   47篇
  1997年   41篇
  1996年   33篇
  1995年   34篇
  1994年   30篇
  1993年   40篇
  1992年   9篇
  1991年   11篇
  1990年   16篇
  1989年   34篇
  1988年   30篇
  1987年   21篇
  1986年   21篇
  1985年   20篇
  1984年   13篇
  1983年   6篇
  1982年   8篇
  1981年   5篇
  1980年   12篇
  1979年   6篇
  1978年   5篇
  1977年   8篇
  1976年   1篇
  1975年   3篇
  1974年   1篇
排序方式: 共有853条查询结果,搜索用时 593 毫秒
91.
大肠癌免疫组化表达与临床病理的关系   总被引:1,自引:0,他引:1  
目的:探讨大肠癌CEA、P53、nm23、Ki-67、MRP免疫组化表达特点和相互关系,及其与临床病理的关系.方法:回顾性分析2003-01/2006-07我院收治的73例大肠癌患者的临床病理及随访资料,并对其石蜡标本采用免疫组化SP染色法检测CEA、P53、nm23、Ki-67、MRP,分析其免疫组化特点及其与临床病理之间的关系.结果:CEA、P53、nm23、Ki-67、MRP在大肠癌中的阳性表达率依次为82.2%、68.5%、75.3%、84.9%和64.4%.CEA、MRP与大肠癌患者的各因素无统计学差异.P53、Ki-67和nm23与肿瘤的Dukes分期和淋巴结转移有关, P53、Ki-67在Dukes C、D期的阳性表达率(依次为82.8%和100%1明显高于Dukes A、B期者(59.1%和75.0%)(P<0.05),而nm23在Dukes C、D期的阳性表达率(58.6%)明显低于Dukes A、B期者(86.4%)(P<0.05).CEA与nm23的表达呈明显的负相关(r=-0.296,P=0.011),而P53和Ki-67表达之间呈现明显的正相关(r= 0.308,P=0.008),其他各指标间的表达无相关性.nm23、P53和Ki-67与预后因素关系明显,nm23在生存期≥3 a患者的阳性表达率(92.9%)高于生存期<3 a者(71.2%)(P<0.05),而P53和Ki-67在生存期≥3 a患者的阳性表达率(依次为42.9%和64.3%)明显低于生存期<3 a者(74.6%和89.8%)(P<0.05).结论:P53、Ki-67和nm23的表达与大肠癌的侵袭转移和预后密切相关.CEA可能是大肠癌的侵袭转移的促进因素.MRP所引起的耐药机制是一个相对独立的机制.CEA、P53、nm23、Ki-67可作为判断大肠癌恶性程度、侵袭转移以及预后的指标.  相似文献   
92.
We studied pituitary-gonadal function during the first year of life in 48 boys born with 56 undescended testes in order to test the hypotheses that functional insufficiency of the hypothalamo-pituitary-gonadal axis and disorders of testosterone (T) biosynthesis occur in such boys. Cryptorchidism persisted for longer than 1 yr in 29 boys (30 testes; group I), whereas spontaneous descent occurred in 19 boys (20 testes; group II), in 6 after the sixth month. A control group (group III) included 160 boys. Basal and peak LHRH-stimulated serum LH and FSH and basal serum T values were determined at 3, 6, and 12 months. Serum T, dihydrotestosterone (DHT), progesterone (P), 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone sulfate, and androstenedione before and after hCG administration were determined at age 1 yr. Comparing the 3 groups, cross-sectional evaluation revealed no significant differences in basal or peak LHRH-stimulated serum LH and FSH levels, except that basal serum LH levels were slightly higher in group II than in group III. Comparing groups I and II, longitudinal evaluation revealed similar basal and peak LHRH-stimulated serum LH and FSH values, with comparable changes with time. Basal serum T, DHT, and T precursor levels were similar in all three groups, with similar rises of T and DHT and variable minimal increases in androstenedione and dehydroepiandrosterone sulfate after hCG stimulation. We conclude that during the first year of life, boys with cryptorchidism have no functional insufficiency of the hypothalamo-pituitary-gonadal axis or disorders in T biosynthesis.  相似文献   
93.
Hereditary elliptocytosis (HE) is a heterogeneous disorder of red blood cells frequently associated with abnormal limited tryptic digestion of the alpha I domain of spectrin and impaired spectrin dimer self- association. We studied two related individuals with poikilocytic hereditary elliptocytosis (HE) of different severity. Limited tryptic digestion of spectrin from these individuals showed the presence of a variant alpha I/50b Kd peptide at the expense of the normal alpha I/80 Kd peptide. Amino acid sequence analysis of the abnormal peptide showed that the proteolytic cleavage occurred after the arginine at position 470 of the alpha spectrin chain. Spectrin from these patients had an impaired ability to undergo self-association, as evidenced by increased amounts of spectrin dimers in 4 degrees C extracts of erythrocyte membrane from affected individuals. The polymerase chain reaction was used to study the DNA sequence of the alpha spectrin gene encoding the region of the alpha spectrin chain surrounding the abnormal proteolytic cleavage site. We detected the in-frame deletion of the trinucleotide CAT, encoding histidine 469, two amino acid residues to the N-terminal side of the abnormal proteolytic cleavage site between residues 470 and 471. Similar to many other defects of spectrin associated with HE, this deletion occurs in helix three of repeat 5 of the proposed triple helical model of spectrin repeats.  相似文献   
94.

Background

BEIT CURE International Hospital (BCIH) opened in 2002 providing orthopaedic surgical services to children in Malawi. This study reviews the hospital''s progress 10 years after establishment of operational services. In addition we assess the impact of the hospital''s Malawi national clubfoot programme (MNCP) and influence on orthopaedic training.

Methods

All operative paediatric procedures performed by BCIH services in the 10th operative year were included. Data on clubfoot clinic locations and number of patients treated were obtained from the MNCP. BCIH records were reviewed to identify the number of healthcare professionals who have received training at the BCIH.

Results

609 new patients were operated on in the 10th year of hospital service. Patients were treated from all regions; however 60% came from Southern regions compared with the 48% in the 5th year. Clubfoot, burn contracture and angular lower limb deformities were the three most common pathologies treated surgically. In total BCIH managed 9,842 patients surgically over a 10-year period. BCIH helped to establish and co-ordinate the MNCP since 2007. At present the program has a total of 29 clinics, which have treated 5748 patients. Furthermore, BCIH has overseen the full or partial training of 5 orthopaedic surgeons and 82 orthopaedic clinical officers in Malawi.

Conclusion

The BCIH has improved the care of paediatric patients in a country that prior to its establishment had no dedicated paediatric orthopaedic service, treating almost 10,000 patients surgically and 6,000 patients in the MNCP. This service has remained consistent over a 10-year period despite times of global austerity. Whilst the type of training placement offered at BCIH has changed in the last 10 years, the priority placed on training has remained paramount. The strategic impact of long-term training commitments are now being realised, in particular by the addition of Orthopaedic surgeons serving the nation.  相似文献   
95.
96.
In a prospective hospital based study, during the period from Jan 95 to Dec 96, 3100 consecutively delivered live newborns were studied for the incidence of low birth weight neonates and to evaluate the associated risk factors. One thousand fourteen newborns were classified as low birth weight babies. The incidence expressed per 1000 live births was 327 (32.7%). Of these, 815 (80.4%) were small for gestational age neonates and 199 (19.6%) were preterm neonates. Five hundred seventy small for gestational age neonates (70%) were weighing between 2001 to 2500 gms. Mothers belonging to the age group of 19-25 years delivered the maximum number of low birth weight babies (618/1014) and of these 82.8% were small for gestational age neonates. There were 48 neonates with low birth weight born to mothers below the age of 18 years. Primiparous mothers were found to contribute higher number of low birth weight neonates (414/1014). Spacing as a factor did not show any major difference. Two hundred sixty two low birth weight neonates were born to mothers with significant obstetrical problems such as pregnancy induced hypertension, bad obstetrical history and premature rupture of membranes. The incidence of 32.7% of low birth weight babies is high enough to ring alarm bells.  相似文献   
97.
OBJECTIVES—This report describes successfulanaesthesia and electroconvulsive therapy (ECT) in a patient with anunruptured basilar artery aneurysm. ECT is associated with ahyperdynamic state characterised by arterial hypertension, tachycardia,and considerably increased cerebral blood flow rate and velocity. Theseresponses pose an increased risk for subarachnoid haemorrhage when anintracranial aneurysm coexists.
METHODS—A 54 year old woman presented for ECT. Shehad a 20 year history of major depression which was unresponsive tothree different antidepressant drugs. There was also an unruptured 5 mmsaccular aneurysm at the basilar tip, which had been documented bycerebral angiography, but its size had remained unchanged for theprevious four years. After she declined surgical intervention, she gave informed consent for ECT. During a series of seven ECT sessions middlecerebral artery flow velocity was recorded by a pulsed transcranialDoppler ultrasonography system. She was pretreated with 50 mg oralatenolol daily, continuing up to the day of the last ECT andimmediately before each treatment, sodium nitroprusside was infused ata rate of 30 µg/min, to reduce systolic arterial pressure to 90-95mm Hg.
RESULTS—Systolic flow velocity during the awakestate ranged from 62-75 cm/s, remaining initially unchanged withsodium nitroprusside infusion. After induction of anaesthesia (0.5 mg/kg methohexitone and 0.9 mg/kg succinylcholine), flow velocitiesdecreased to 39-54 cm/s, reaching maximal values of 90 cm/s (only 20%above baseline) after ECT. These flow velocities recorded post-ECT wereconsiderably below the more than twofold increase recorded when noattenuating drugs were used. Systolic arterial blood pressure reachedmaximal values of 110-140 mm Hg and heart rate did not exceed 66 bpm. Rapid awakening followed each treatment, no focal or globalneurological signs were apparent, and the patient was discharged in remission.
CONCLUSION—In a patient with major depression anda coexisting intracerebral saccular aneurysm who was treated with ECT,the combination of β blockade with atenolol and intravenous infusionof sodium nitroprusside prevented tachycardia and hypertension, andgreatly attenuated the expected increase in flow velocity in the middle cerebral artery.

  相似文献   
98.
注射用双黄连与几种抗生素联合体外抑菌活性的研究   总被引:11,自引:0,他引:11  
目的:探讨注射用双黄连与抗生素联合使用的临床意义。方法:参考中国药典抗生素微生物检定法,测定注射用双黄连与头孢拉定等6种抗生素配伍使用后对金葡菌及克雷白氏肺炎杆菌的抑菌圈直径的变化。结果:注射用双黄连与氨苄青霉素、普鲁卡因青霉素、头孢唑啉钠及红霉素配伍后对金葡萄的体外抑菌效果明显增强;与头孢拉定、头孢唑啉钠及普鲁卡因青霉素配伍后对克氏肺炎杆菌的体外抑菌效果有不同程度的增强。结论:对于不同的细菌感染  相似文献   
99.
猪脑钠素及其类似物的合成   总被引:1,自引:0,他引:1  
以固相多肽合成方法合成了猪的二十六肽脑钠素(BNP)和它的一个类似物(Mpr4,D-Ala6,13)-BNP(4-24)-NH2,保护肽用HF裂解除去保护基、在碱性条件下空气氧化形成二硫桥后,粗产物经凝胶过滤和高效液相色谱分离纯化,均有与天然脑钠素相同的活性。合成肽相对于树脂初始取代量的产率分别为9.56%和11.03%。  相似文献   
100.
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