全文获取类型
收费全文 | 34700篇 |
免费 | 2224篇 |
国内免费 | 173篇 |
专业分类
耳鼻咽喉 | 325篇 |
儿科学 | 954篇 |
妇产科学 | 761篇 |
基础医学 | 5070篇 |
口腔科学 | 2674篇 |
临床医学 | 2663篇 |
内科学 | 7116篇 |
皮肤病学 | 770篇 |
神经病学 | 2711篇 |
特种医学 | 732篇 |
外国民族医学 | 1篇 |
外科学 | 4106篇 |
综合类 | 376篇 |
一般理论 | 8篇 |
预防医学 | 3783篇 |
眼科学 | 614篇 |
药学 | 2325篇 |
中国医学 | 299篇 |
肿瘤学 | 1809篇 |
出版年
2023年 | 289篇 |
2022年 | 640篇 |
2021年 | 1296篇 |
2020年 | 832篇 |
2019年 | 1107篇 |
2018年 | 1250篇 |
2017年 | 898篇 |
2016年 | 955篇 |
2015年 | 1132篇 |
2014年 | 1464篇 |
2013年 | 1781篇 |
2012年 | 2767篇 |
2011年 | 3019篇 |
2010年 | 1564篇 |
2009年 | 1250篇 |
2008年 | 2132篇 |
2007年 | 2005篇 |
2006年 | 1869篇 |
2005年 | 1612篇 |
2004年 | 1425篇 |
2003年 | 1238篇 |
2002年 | 1158篇 |
2001年 | 598篇 |
2000年 | 641篇 |
1999年 | 519篇 |
1998年 | 227篇 |
1997年 | 163篇 |
1996年 | 166篇 |
1995年 | 150篇 |
1994年 | 114篇 |
1993年 | 96篇 |
1992年 | 243篇 |
1991年 | 224篇 |
1990年 | 214篇 |
1989年 | 210篇 |
1988年 | 193篇 |
1987年 | 143篇 |
1986年 | 133篇 |
1985年 | 135篇 |
1984年 | 115篇 |
1983年 | 95篇 |
1982年 | 54篇 |
1979年 | 90篇 |
1978年 | 79篇 |
1977年 | 54篇 |
1975年 | 58篇 |
1974年 | 66篇 |
1973年 | 66篇 |
1970年 | 60篇 |
1967年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
91.
92.
Stimulation of enzyme secretion from isolated pancreatic acini by Clostridium difficile toxin B 总被引:1,自引:0,他引:1
G D Vesenka A P Majumdar M A Dubick D M Lyerly T D Wilkins J Silva M C Geokas 《Toxicology letters》1986,34(2-3):261-269
Exposure of isolated rat pancreatic acini to increasing concentrations (10 ng - 800 ng/ml) of toxin B from Clostridium difficile produced a biphasic effect on the rate of secretion of amylase, trypsinogen, and chymotrypsinogen. Whereas doses of toxin B from 10-30 ng/ml increased enzyme secretion by 15-20%, doses between 30 ng and 60 ng/ml showed a regression of this effect, whereafter the rate of secretion of amylase, trypsinogen, and chymotrypsinogen increased with increasing concentrations of the toxin. Toxin B concentration of 800 ng/ml enhanced amylase, trypsinogen and chymotrypsinogen secretion by 119%, 185% and 195%, respectively, when compared with the basal level. Stimulation of enzyme secretion by toxin B was not affected by the presence of either actinomycin-D or cycloheximide, at a concentration which inhibited acinar RNA or protein synthesis by 80-90%. Although toxin B as well as CCK8, carbachol and secretin by themselves caused significant stimulation in amylase, trypsinogen and chymotrypsinogen secretion from isolated pancreatic acini, toxin B together with either CCK8, carbachol or secretin produced no further augmentation in enzyme secretion than what was observed with the secretagogues alone. It is concluded that toxin B of Cl. difficile exerts a direct effect on pancreatic acinar cells as evidenced by stimulation of enzyme secretion. 相似文献
93.
94.
95.
96.
97.
N M Trugo C M Donangelo J C Koury M I Silva L A Freitas 《European journal of clinical nutrition》1988,42(6):497-507
The purpose of this study was to assess the concentration and binding pattern of zinc, iron, folate and vitamin B12 in milk of Brazilian women of low socioeconomic status giving birth at term or preterm, during early lactation. Protein, fat, total solids and ash concentrations were also determined. Protein and zinc concentrations decreased significantly as lactation proceeded whereas milk fat and folate increased with the lactation period. Total solids, ash, iron and vitamin B12 remained unchanged. Zinc was present mainly in the whey fraction while less than half of the total iron was present in this fraction, with no significant change due to stage of lactation. Unsaturated folate and vitamin B12 binding capacities and percentage of saturation of the folate binding protein increased with the stage of lactation. The vitamin B12 binding protein was highly unsaturated in all samples. There was no significant difference between term and preterm samples in the parameters investigated. Correlation analysis between milk components indicated significant relationships between total solids and fat, total zinc and whey zinc, folate and total folate binding capacity, unsaturated and total folate binding capacity, and unsaturated and total B12 binding capacity. In general, the nutrient concentrations found in this study are in good agreement with published data on milk composition of women from developed countries, with the possible exceptions of folate, which was lower, and iron, which was higher. The correlation of folate concentration with its binding protein found in this work supports the hypothesis of a regulatory role for folate levels in milk exerted by the folate binding protein in the mammary gland. 相似文献
98.
99.
†Francesco Mari Carlo Di Bonaventura ‡Nicola Vanacore Jinane Fattouch Anna Elisabetta Vaudano Gabriella Egeo †Alfredo Berardelli †Mario Manfredi Massimiliano Prencipe †Anna Teresa Giallonardo 《Epilepsia》2006,47(S5):64-67
Summary: Purpose: Psychogenic nonepileptic seizures (PNES) are episodes that may resemble epileptic seizures (ES) but are not associated with abnormal electrical discharges in the brain. Video-EEG recording of a typical episode is considered the best diagnostic tool available. PNES are, however, also documented in patients with epilepsy (PNES/ES). The purpose of this study was to assess this comorbid population, focusing on the differences between patients with PNES/ES and patients with PNES alone.
Methods: We reviewed 110 PNES episodes, occurring spontaneously or induced by means of suggestion techniques, recorded in our video-EEG laboratory over a period of eight years. We identified two subgroups of patients, consisting of 85 PNES cases and 25 PNES/ES cases, and assessed any differences in their characteristics by reviewing a number of variables (age, sex, clinical features, antiepileptic therapy, age of onset, time to diagnosis, pathological history, and length of follow-up).
Results: The comparison between the two subgroups revealed that PNES/ES patients displayed some statistically significant differences when compared with PNES alone patients, i.e., younger age, a higher percentage of spontaneously activated events, a shorter disease duration, a longer time to PNES diagnosis, and a lower percentage lost at follow-up.
Conclusions: This study confirms that PNES is a common, though probably underestimated, occurrence in epilepsy services. Our results shed light on some different characteristics between PNES and PNES/ES patients. 相似文献
Methods: We reviewed 110 PNES episodes, occurring spontaneously or induced by means of suggestion techniques, recorded in our video-EEG laboratory over a period of eight years. We identified two subgroups of patients, consisting of 85 PNES cases and 25 PNES/ES cases, and assessed any differences in their characteristics by reviewing a number of variables (age, sex, clinical features, antiepileptic therapy, age of onset, time to diagnosis, pathological history, and length of follow-up).
Results: The comparison between the two subgroups revealed that PNES/ES patients displayed some statistically significant differences when compared with PNES alone patients, i.e., younger age, a higher percentage of spontaneously activated events, a shorter disease duration, a longer time to PNES diagnosis, and a lower percentage lost at follow-up.
Conclusions: This study confirms that PNES is a common, though probably underestimated, occurrence in epilepsy services. Our results shed light on some different characteristics between PNES and PNES/ES patients. 相似文献
100.
Neuropsychologic symptoms in the migraine syndrome 总被引:1,自引:0,他引:1
Twenty patients with complex neuropsychologic symptoms associated with classic migraine were selected from a group of 200 patients with vascular headache. Twenty types of symptoms were found and grouped into six categories (language, visual symptoms, cognitive-dysmnesic symptoms, olfactory-gustatory hallucinations, automatisms, and somatosensory symptoms). Some of the symptoms found have apparently not been reported previously. The importance of the analysis of this complex neuropsychologic set of symptoms and of the possible consequences of complicated, frequent vascular headache is emphasized. 相似文献