全文获取类型
收费全文 | 1319篇 |
免费 | 84篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 86篇 |
妇产科学 | 25篇 |
基础医学 | 129篇 |
口腔科学 | 37篇 |
临床医学 | 135篇 |
内科学 | 281篇 |
皮肤病学 | 16篇 |
神经病学 | 59篇 |
特种医学 | 178篇 |
外科学 | 154篇 |
综合类 | 7篇 |
预防医学 | 49篇 |
眼科学 | 35篇 |
药学 | 93篇 |
肿瘤学 | 117篇 |
出版年
2023年 | 6篇 |
2021年 | 10篇 |
2019年 | 8篇 |
2018年 | 24篇 |
2017年 | 14篇 |
2016年 | 7篇 |
2015年 | 15篇 |
2014年 | 31篇 |
2013年 | 40篇 |
2012年 | 40篇 |
2011年 | 46篇 |
2010年 | 46篇 |
2009年 | 39篇 |
2008年 | 32篇 |
2007年 | 43篇 |
2006年 | 45篇 |
2005年 | 42篇 |
2004年 | 65篇 |
2003年 | 55篇 |
2002年 | 39篇 |
2001年 | 43篇 |
2000年 | 42篇 |
1999年 | 37篇 |
1998年 | 44篇 |
1997年 | 33篇 |
1996年 | 33篇 |
1995年 | 32篇 |
1994年 | 33篇 |
1993年 | 22篇 |
1992年 | 33篇 |
1991年 | 32篇 |
1990年 | 23篇 |
1989年 | 44篇 |
1988年 | 29篇 |
1987年 | 21篇 |
1986年 | 23篇 |
1985年 | 31篇 |
1984年 | 14篇 |
1983年 | 13篇 |
1982年 | 23篇 |
1981年 | 18篇 |
1980年 | 13篇 |
1978年 | 9篇 |
1977年 | 17篇 |
1976年 | 18篇 |
1975年 | 13篇 |
1974年 | 10篇 |
1973年 | 7篇 |
1971年 | 6篇 |
1969年 | 6篇 |
排序方式: 共有1406条查询结果,搜索用时 31 毫秒
1.
Controversy exists about the value of ultrasonography of meniscal tears. We therefore examined 101 knee joints of 99 patients in a prospective study. Prior to the arthroscopy the menisci were scanned from an independent team by using 7.5 and 10.0 MHz ultrasound waves. 81 meniscal tears were seen at arthroscopy; 36% of these tears could not be detected with the scanner (? false negative results) while 20% of intact menisci showed positive echogenic structures, which were analysed as meniscal tears. It seems that ultrasonography of the menisci is still of experimental use without any clinical importance. 相似文献
2.
Acute appendicitis: CT and US correlation in 100 patients 总被引:19,自引:1,他引:18
3.
Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations 总被引:2,自引:0,他引:2
Hulnick DH; Megibow AJ; Balthazar EJ; Gordon RB; Surapenini R; Bosniak MA 《Radiology》1987,164(3):611-615
Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm. 相似文献
4.
5.
beta-Hydroxybutyrate fuels synaptic function during development. Histological and physiological evidence in rat hippocampal slices. 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《The Journal of clinical investigation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Y Izumi K Ishii H Katsuki A M Benz C F Zorumski 《The Journal of clinical investigation》1998,101(5):1121-1132
To determine whether ketone bodies sustain neuronal function as energy substrates, we examined the effects of beta-hydroxybutyrate (betaHB) on synaptic transmission and morphological integrity during glucose deprivation in rat hippocampal slices. After the depression of excitatory postsynaptic potentials (EPSPs) by 60 min of glucose deprivation, administration of 0.5-10 mM D-betaHB restored EPSPs in slices from postnatal day (PND) 15 rats but not in slices from PND 30 or 120 rats. At PND 15, adding D-betaHB to the media allowed robust long-term potentiation of EPSPs triggered by high frequency stimulation, and prevented the EPSP-spike facilitation that suggests hyperexcitability of neurons. Even after PND 15,D-betaHB blocked morphological changes produced by either glucose deprivation or glycolytic inhibition. These results indicate that D-betaHB is not only able to substitute for glucose as an energy substrate but is also able to preserve neuronal integrity and stability, particularly during early development. 相似文献
6.
Steenbergen EJ; Verhagen OJ; van Leeuwen EF; van den Berg H; von dem Borne AE; van der Schoot CE 《Blood》1995,86(2):692-702
Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL. 相似文献
7.
The survival of 409 patients with breast cancer treated by surgery +/- adjuvant therapy is controlled in a retrospective study. 65 (15.9%) patients subsequently suffered from loco-regional recurrences. 41 (63.1%) of these patients showed either simultaneously with the loco-regional recurrence or at the latest within 2 1/2 years after the diagnosis of the loco-regional recurrence distant metastasis. The incidence of the distant metastasis is the more probable the shorter the interval between the primary treatment and the occurrence of the loco-regional recurrence. More prognostic factors for the survival after the diagnosis of the loco-regional recurrence are discussed. 相似文献
8.
9.
Zusammenfassung Hämaturie und Proteinurie sind häufige Befunde im Kindesalter. Die Aufgabe des Kinderarztes ist es, beim Auftreten dieser Symptome die Dringlichkeit weiterer Untersuchungen abzuschätzen und diese evtl. durchzuführen, um die zugrunde liegenden Erkrankungen aufzudecken. Algorithmen zu Hämaturie und Proteinurie, die in dieser Mitteilung vorgestellt und diskutiert werden, sollen eine gezielte Diagnostik ermöglichen und überflüssige Untersuchungen vermeiden. 相似文献
10.