全文获取类型
收费全文 | 28037篇 |
免费 | 1552篇 |
国内免费 | 71篇 |
专业分类
耳鼻咽喉 | 434篇 |
儿科学 | 1127篇 |
妇产科学 | 909篇 |
基础医学 | 4564篇 |
口腔科学 | 590篇 |
临床医学 | 2287篇 |
内科学 | 5543篇 |
皮肤病学 | 747篇 |
神经病学 | 2720篇 |
特种医学 | 1143篇 |
外国民族医学 | 14篇 |
外科学 | 4060篇 |
综合类 | 121篇 |
一般理论 | 4篇 |
预防医学 | 1464篇 |
眼科学 | 511篇 |
药学 | 1506篇 |
中国医学 | 25篇 |
肿瘤学 | 1891篇 |
出版年
2022年 | 228篇 |
2021年 | 433篇 |
2020年 | 283篇 |
2019年 | 390篇 |
2018年 | 476篇 |
2017年 | 384篇 |
2016年 | 536篇 |
2015年 | 522篇 |
2014年 | 713篇 |
2013年 | 895篇 |
2012年 | 1320篇 |
2011年 | 1391篇 |
2010年 | 687篇 |
2009年 | 736篇 |
2008年 | 1252篇 |
2007年 | 1346篇 |
2006年 | 1256篇 |
2005年 | 1271篇 |
2004年 | 1062篇 |
2003年 | 1062篇 |
2002年 | 966篇 |
2001年 | 907篇 |
2000年 | 939篇 |
1999年 | 796篇 |
1998年 | 359篇 |
1997年 | 275篇 |
1996年 | 223篇 |
1995年 | 212篇 |
1994年 | 190篇 |
1993年 | 188篇 |
1992年 | 483篇 |
1991年 | 510篇 |
1990年 | 490篇 |
1989年 | 406篇 |
1988年 | 388篇 |
1987年 | 403篇 |
1986年 | 394篇 |
1985年 | 392篇 |
1984年 | 271篇 |
1983年 | 214篇 |
1982年 | 141篇 |
1981年 | 147篇 |
1979年 | 261篇 |
1978年 | 185篇 |
1977年 | 156篇 |
1976年 | 153篇 |
1975年 | 167篇 |
1974年 | 197篇 |
1973年 | 169篇 |
1972年 | 155篇 |
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
101.
Lyme Neuroborreliosis (LNB) has repeatedly been reported to cause cerebral vasculitis. However, there is no reliable information about the incidence of cerebral vessel affection. The majority of reports deal with ischaemic consequences, and there are a few reports of subarachnoid haemorrhage (SAH). We report a case of otherwise unexplained intracerebral haemorrhage (ICH) where clinical and laboratory tests have shown LNB. Late stage LNB might not only cause ischaemic, but haemorrhagic stroke as well. 相似文献
102.
Fifty six children with a birth weight of less than 1500 g and gestational age less than 34 weeks were studied at a mean age of 7.7 years. All had required mechanical ventilation, 36 suffered from hyaline membrane disease, 17 from atelectasis and three from pneumonia. Of these patients 37 developed broncho-pulmonary dysplasia (BPD). The study included skin prick test, measurement of ciliary beat frequency, chest X-ray, whole-body plethysmography and histamine challenge. Eight patients suffered from recurrent pulmonary infections up to the age of 4 years. Eleven children had a positive skin prick test. Three suffered from allergic asthma and six from hay-fever. The family history of atopy in these premature infants was no different from that of the general population. Ciliary beat frequency was normal in all cases (frequency: 11.8 +/- 1.8 Hz). In 34 patients X-rays showed minimal changes (peribronchial thickening n = 6, mild emphysema n = 28). Pulmonary function was normal except for an increase of thoracic gas volume which was correlated to grade of BPD according to Northway. There was a significant correlation between oxygen-score and radiological stage of BPD (r = 0.7). Histamine challenge showed hyperresponsiveness in 53% of the children. Eight patients showed a threshold similar of mild asthma (less than 1000 micrograms histamine per ml). The degree of airway hyperreactivity was correlated to the grade of BPD (r = 0.7; p less than 0.01) and the oxygen-score (r = -0.63; p less than 0.05). The oxygen-score may be considered a predictor of hyperresponsiveness and pulmonary outcome in later childhood. 相似文献
103.
Antitumor effect of synthetic derivatives of lipid A in an experimental model of colon cancer in the rat 总被引:1,自引:0,他引:1
Colon carcinoma is one of the most frequent causes of cancer death in industrialized countries. The patients generally die of the metastases. In a colon cancer rat model, the authors have shown that lipopolysaccharides from Escherichia coli induced the regression of carcinomatosis and cured 20%-30% of the rats. Some synthetic derivatives of lipid A, which are less toxic than lipopolysaccharides, were injected 14 days after the tumor cells. They induced the complete regression of peritoneal carcinomatosis consisting of numerous nodules measuring 1-5 mm in 20%-30% of rats. Only compounds with three or more hydroxymyristic acid residues were effective. In vivo effects were correlated with the capacity to induce the production of interleukin 1 and tumor necrosis factor but not with the capacity to induce macrophage-mediated cytolysis. It is therefore possible to synthesize weakly toxic derivatives of lipopolysaccharides retaining their antitumoral property in vivo. 相似文献
104.
Jesper Carl Thomas Bro Christensen Hans von der Maase 《Acta oncologica (Stockholm, Sweden)》1992,31(7):749-753
This study presents an analysis on longitudinal tumour marker series in twenty-two patients with non-seminomatous germ cell cancers treated with cisplatinum (DDP) based combination chemotherapy. Series of alphafoetoprotein (AFP), human chorionic gonadotropin (HCG) and lactate dehydrogenase (LDH) were analyzed applying a dynamic mathematical marker model. The model analysis provided quantitated values for growth rate and treatment response in the marker producing cells. The analysis showed that LDH had to be above 2 000 U/l to be a trustworthy tumour marker. HCG producing cells tended to grow faster than AFP producing cells, and were 3-5-fold more sensitive to the chemotherapy given than AFP producing cells. Treatment response versus DDP dose appeared to be bi-phasic, but with no significant change in treatment efficiency within the given range of DDP doses. 相似文献
105.
The inheritance of alcohol abuse and other psychopathology in 862 men and 913 women adopted by non-relatives, was studied. Both male and female adoptees were at greater risk to develop alcohol abuse if their biological, but not their adoptive, parents were alcoholic. Three types of families with alcoholism were distinguished that differed in frequency of alcohol abuse, somatoform disorders in women and in relation to antisocial behaviour in male adoptees. The combination of both genetic and environmental risk factors was necessary for the development of alcoholism in the most common, milieu-limited type of alcoholism. In families with a less common, male-limited, type of vulnerability, alcohol abuse was highly heritable in men, but women had multiple somatic complaints and seldom abuse. In a third type of family the common vulnerability was expressed as antisocial behaviour with violent criminality and recurrent alcohol abuse in males, but as high frequency somatization in female relatives. 相似文献
106.
107.
108.
109.
R Karlsson S Edén L Eriksson B von Schoultz 《Gynecologic and obstetric investigation》1992,34(4):197-201
The interpretation of previous data on osteocalcin during pregnancy has been complicated by the fact that serum levels, at least in nonpregnant women, display a significant circadian variation. In the present study, serum concentrations of osteocalcin were recorded for 24 h in 12 individual women. In 4 nonpregnant women, there were striking diurnal fluctuations during the sampling period, with values ranging from 0.5 to 4.0 ng/ml. One woman who was investigated in the 11th week of pregnancy showed similar fluctuations in osteocalcin concentrations whereas in the 15th and 17th week values were much lower with minor fluctuations. In 4 women investigated during late pregnancy (weeks 34-38), osteocalcin serum levels were extremely low (range 0.2-0.4 ng/ml), often below the detection limit of the assay, and there was no diurnal variation. Also, in 1 lactating woman, osteocalcin serum levels were low (0.3-0.8 ng/ml) and stable. Low osteocalcin values during pregnancy may indicate a reduced bone turnover possibly mediated via an altered estrogen and growth hormone secretion. 相似文献
110.
First results are presented to determine the maturity of fetal lung by sonography. Using the fetal liver as a reference-organ we are avoiding the known pitfalls which made it impossible in the past to standardize the fetal lung changes depending on the age of gestation. We examined 104 patients between week 27 and week 41. In one ultrasound section cut we depicted as well lung and liver. According to the known A-mode we registered frequencies in both organs. The registered frequencies were entered digitally into a computer and checked for f(mean), f(max) and f(min). Afterwards the frequencies of the lung were divided by those of the liver. Of all weeks of gestation the mean value and standard deviation were calculated. We found the liver as an adequate reference-organ, since there is no change of the reflection pattern between the different weeks of gestation, while there are significant changes to be registered in the fetal lung, a cutting line being week 35. A quotient of f(mean) lower than 1.1 hints to lung maturity while values over 1.1 point to immaturity. This was confirmed by several cases of analysis of amniotic fluid (L/S-ratio). Further comparisons with amniotic fluid results will have to validate these findings. 相似文献