全文获取类型
收费全文 | 12168篇 |
免费 | 622篇 |
国内免费 | 125篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 164篇 |
妇产科学 | 111篇 |
基础医学 | 1297篇 |
口腔科学 | 122篇 |
临床医学 | 2155篇 |
内科学 | 664篇 |
皮肤病学 | 155篇 |
神经病学 | 1165篇 |
特种医学 | 158篇 |
外科学 | 474篇 |
综合类 | 3066篇 |
一般理论 | 1篇 |
预防医学 | 1541篇 |
眼科学 | 57篇 |
药学 | 1036篇 |
47篇 | |
中国医学 | 400篇 |
肿瘤学 | 248篇 |
出版年
2024年 | 50篇 |
2023年 | 188篇 |
2022年 | 358篇 |
2021年 | 441篇 |
2020年 | 453篇 |
2019年 | 302篇 |
2018年 | 278篇 |
2017年 | 342篇 |
2016年 | 347篇 |
2015年 | 370篇 |
2014年 | 1037篇 |
2013年 | 1042篇 |
2012年 | 1046篇 |
2011年 | 1066篇 |
2010年 | 880篇 |
2009年 | 691篇 |
2008年 | 708篇 |
2007年 | 636篇 |
2006年 | 526篇 |
2005年 | 386篇 |
2004年 | 270篇 |
2003年 | 253篇 |
2002年 | 166篇 |
2001年 | 150篇 |
2000年 | 140篇 |
1999年 | 98篇 |
1998年 | 65篇 |
1997年 | 65篇 |
1996年 | 42篇 |
1995年 | 53篇 |
1994年 | 46篇 |
1993年 | 31篇 |
1992年 | 29篇 |
1991年 | 24篇 |
1990年 | 31篇 |
1989年 | 18篇 |
1988年 | 30篇 |
1987年 | 29篇 |
1986年 | 13篇 |
1985年 | 23篇 |
1984年 | 30篇 |
1983年 | 14篇 |
1982年 | 27篇 |
1981年 | 11篇 |
1980年 | 18篇 |
1979年 | 20篇 |
1978年 | 13篇 |
1977年 | 12篇 |
1976年 | 10篇 |
1975年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Primary choriocarcinoma and human chorionic gonadotrophin‐producing giant cell carcinoma of the lung: are they independent entities? 总被引:2,自引:0,他引:2
AIMS: Human chorionic gonadotrophin (hCG) is a useful marker for chorionic proliferative disorders, such as choriocarcinoma. Although hCG synthesis in lung cancers is frequent, primary pulmonary choriocarcinoma (PCC) is rare. To clarify the differences between primary choriocarcinoma and hCG-producing giant cell carcinoma (GCC) of the lung, we compared the clinicopathological and immunohistochemical findings of these tumours. METHODS AND RESULTS: Three patients, one with PCC and two with hCG-producing GCC, were included in this study. They were all middle-aged men and habitual smokers. The growth of these tumours and the progression of the clinical courses were extremely rapid, and the patients all died within 8 months after the pulmonary tumours were found. Haemorrhagic appearance was a common macroscopic feature of the specimens obtained. Microscopically, both types of tumours mainly consisted of atypical polygonal cells. While PCC contained many syncytial trophoblast-like multinucleated cells that had strong immunoreactivity for anti-hCG, such cells were relatively few in hCG-producing GCC. These histological and immunohistochemical findings reflected the serum test result for hCG, which was higher in the case of PCC. CONCLUSIONS: There are a few differences between PCC and hCG-producing GCC, as described above. Reliable distinction between them seems to be difficult for pathologists and worthless for clinicians. 相似文献
62.
Bapi RS Doya K Harner AM 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2000,132(2):149-162
To investigate the representation of motor sequence, we tested transfer effects in a motor sequence learning paradigm. We hypothesize that there are two sequence representations, effector independent and dependent. Further, we postulate that the effector independent representation is in visual/spatial coordinates, that the effector dependent representation is in motor coordinates, and that their time courses of acquisition during learning are different. Twelve subjects were tested in a modified 2x10 task. Subjects learned to press two keys (called a set) successively on a keypad in response to two lighted squares on a 3x3 display. The complete sequence to be learned was composed of ten such sets, called a hyperset. Training was given in the normal condition and sequence recall was assessed in the early, intermediate, and late stages in three conditions, normal, visual, and motor. In the visual condition, finger-keypad mapping was rotated 90 degrees while the keypad-display mapping was kept identical to normal. In the motor condition, the keypad-display mapping was also rotated 90 degrees, resulting in an identical finger-display mapping as in normal. Subjects formed two groups with each group using a different normal condition. One group learned the sequence in a standard keypad-hand setting and subsequently recalled the sequence using a rotated keypad-hand setting in the test conditions. The second group learned the sequence with a rotated keypad-hand setting and subsequently recalled the sequence with a standard keypad-hand setting in the test conditions. Response time (RT) and sequencing errors during recall were recorded. Although subjects committed more sequencing errors in both testing conditions, visual and motor, as compared to the normal condition, the errors were below chance level. Sequencing errors did not differ significantly between visual and motor conditions. Further, the sequence recall accuracy was over 70% even by the early stage when the subjects performed the sequence for the first time with the altered conditions, visual and motor. There were parallel improvements thereafter in all the conditions. These results of positive transfer of sequence knowledge across conditions that use dissimilar finger movements point to an effector independent sequence representation, possibly in visual/spatial coordinates. Initially the RTs were similar in the visual and the motor conditions, but with training RTs in the motor condition became significantly shorter than in the visual condition, as revealed by significant interaction for the testing stage and condition term in the repeated measures ANOVA. Moreover, using RTs for single key pressing in the three conditions as baseline indices, it was again observed that RTs in the visual and motor conditions were not significantly different in the early stage, but motor RTs became significantly shorter by the late testing stage. These results support the hypothesis that the motor condition benefits more than the visual because it uses identical effector movements to the normal condition. Further, these results argue for the existence of effector dependent sequence representation, in motor coordinates, which is acquired relatively slowly. The difference in the time course of learning of these two representations may account for the differential involvement of brain areas in early and late learning phases found in lesion and imaging studies. 相似文献
63.
R. Paschke I. Harsch B. Schlote I. Vardarli L. Schaaf S. Kaumeier J. Teuber K. H. Usadel 《Journal of molecular medicine (Berlin, Germany)》1990,68(19):942-950
Summary Although the psychological disturbances accompanying Graves' disease are well known, the time required for normalisation of these disturbances during antithyroid drug treatment is not known. Therefore sequential psychological testing during the course of Graves' disease was done. There are also contradictory results concerning the possible correlation of neurophysiological and psychological test results during the course of Graves' disease with thyroid hormone values. Finally, psychological disturbances have been proposed as possible etiologic factors in Graves' disease.In our study, a significant decrease in anxiety and irritability could be observed at the time euthyroidism was achieved. Self-evaluations of depressivity, activity, exhaustion, well-being, extraversion, introversion, and the ability to concentrate changed 1 or 2 months after euthyroidism was induced. Similar test results could be observed after induction of euthyroidism by antithyroid drugs and subtotal thyroid resection. Therefore the mode of therapy does not seem to influence the course of normalisation of psychological parameters.In contrast to other investigations there was hardly any correlation between thyroid hormone values and psychological test results or the ability to concentrate. Nontheless, patients with Graves' disease showing high scores for depression and anxiety exhibit abnormal peripheral helper/suppressor T-lymphocyte relations. Furthermore, patients suffering from Graves' disease tend to be more anxious than controls. It remains to be determined whether an increased susceptibility to psychological disturbances has led to these alterations of lymphocyte subsets in Graves' disease patients with severe depression and anxiety.Supported by SFB 258 相似文献
64.
美、德、比利时的军官心理选拔 总被引:1,自引:1,他引:1
文章以美国、德国和比利时军官心理选拔的研究现状为切入点,详细介绍了这三个国家军官心理选拔的历史背景、方法、工具、内容、标准以及策略,旨在为未来国内的相关研究提供参考。 相似文献
65.
Medaka fish (Oryzias latipes) were exposed to various doses of X-rays or fast neutrons, and the frequency of micronucleated cells (MNCs) was measured in gills sampled at 12- or 24-hr intervals from 12 to 96 hr after exposure. The resulting time course of MNC frequency was biphasic, with a clear peak 24 hr after exposure, irrespective of the kind of radiation applied and the dose used. The half-life of MNCs induced in the gill tissues by the two exposures fluctuated around 28 hr, with no significant dose-dependent trend for either X-ray- or neutron-exposed fish. As assayed 24 hr after exposure, the MNC frequency increased linearly over the control level with increasing doses of both X-rays and fast neutrons. The relative biological effectiveness (RBE) of fast neutrons to X-rays for MNC induction was estimated to be 4.3 +/- 0.6. This value is close to the RBE value of 5.1 +/- 0.3 reported for fast neutron induction of somatic crossing-over mutations in Drosophila melanogaster that arise from recombination repair of DNA double-strand breaks. These results and other data support our conclusion that the medaka gill cell micronucleus assay is a reliable short-term test for detecting potential inducers of DNA double-strand breaks. 相似文献
66.
Kerstin Eberhardt MD PhD Britt-Marie Larsson Social worker Kerstin Nived Social worker 《Patient education and counseling》1993,20(2-3):93-100
We report the interaction of RA and psychological factors over 2 years in a group of 89 patients with newly established disease. Short-time outcome regarding physical features was fairly good. Disease activity decreased, and disability evaluated by HAQ remained at a low level. Psychological distress as measured by the depression and anxiety subscales of SCL 90 (Symptom Check List) was not very pronounced and not related to disease state factors. A slight decrease of anxiety was recorded after 2 years. A new adjustment test was applied. It contained 13 items focused mainly on negative illness effects such as loss of independence, feelings of guilt, and change of social and leisure time activities. Three factors (regret of lost life values, dysphoric mood, and acceptance) explained 48% of the variance of the 13 items. The validity of the test was acceptable. The patients' degree of adjustment changed slowly or not at all during the 2 years. 相似文献
67.
目的研究试图通过对海口市三甲医院医务人员人格特质的测量与分析,在与全国常模进行对比的情况下,得出海口市三甲医院医务人员人格特质的基本描述,建立医务人员人格特质的常模,为最终科学地建立海南省医学人才人格特质考评体系奠定必要的工作基础,也为海南省医学人才的培养和利用提供一项可行性的管理模式.方法采取分层整群随机抽样方法对海口市五家三甲医院医务人员人格特质进行调查,使用国际著名的人格问卷-加利福尼亚心理调查表CPI作为工具,对海口市三甲医院医务人员人格特质进行调查.结果被调查的海口市三甲医院588名医务人员人格类型分布以Beta型为主,各型分布情况为:Alpha型171人,占29.1%,Beta型302人,占51.4%,Gamma型59人,占10.0%,Delta型56人,占9.5%;在V3自我实现水平上海口市三甲医院医务人员有较高得分,除1例处于第二水平和4例处于第三水平外,其余583例都分别处于第四至第七水平;海口市三甲医院医务人员在20个分量表的测试中,在CS、IN、EM、SC、GI、WB、CM、TO、AI、AC、IE、PY、FX等13个分量表的平均得分上明显高于全国常模组(P〈0.01),而在DO、SY、SP、SA、SO 5个分量表平均得分上明显低于全国常模组(P〈0.01).结论海口市三甲医院医务人员各分量表平均得分大部分高于全国常模水平,尤其是在测量成就潜能方面的3个分量表AC、AI、IE平均得分全部明显高于全国常模水平(P〈0.01),表明海口市三甲医院医务人员较常模有更强烈的成就动机,对智力活动与知识成就有较强的追求,在工作中能更有效地发挥智能,注重办事效率,见识广博,比较适合在激励自由和个人首创精神的场所独立地开展工作,并且能够专心于别人看来较为枯燥的工作.在测量社会价值内化程度的7个分量表中有5个(SC、GI、CM、WB、TO)高于全国常模水平. 相似文献
68.
69.
无症状性脑梗死患者的心理功能测评 总被引:6,自引:0,他引:6
随着高敏度的脑成像技术如CT、MRI在临床的广泛应用 ,发现了许多临床上无明显症状、体征或症状、体征与既往卒中史不相关的梗死灶 ,称之为无症状性脑梗死 (asymptomaticinfarct)或静止性脑梗死(silentcerebralinfarction ,SCI)。虽然这些病人经传统的神经系统检查未发现明显的异常 ,但有学者认为他们存在明显的认知功能障碍、精细运动障碍及情感障碍等。本文对 38例SCI及 30例对照组进行了认知功能、记忆、精细运动、感知觉及情感等方面的评价 ,有利于SCI以及血管性痴呆的早期防… 相似文献
70.
M. Jahn B. Zönnchen W. Köpcke R. Hehlmann 《Journal of molecular medicine (Berlin, Germany)》1988,66(5):190-198
Summary 60 patients with essential thrombocythemia (ET) have been retrospectively and prospectively followed from 1974 through 1987. The presenting signs and symptoms and the course of the disease were analyzed and compared to 10 patients with persisting reactive thrombocytosis selected from 6000 patients with reactive thrombocytosis and to 50 patients with other myeloproliferative diseases. 54 ET-patients presented with complications, 46 with thrombembolic, 3 with hemorrhagic problems and 5 with thrombembolic and hemorrhagic problems. In 6 patients ET was detected accidentally. Disturbances of the microcirculation, mainly of the fingers and the toes, were the most frequent symptom. The average maximal platelet count was 1 207 000/µl. The average platelet count at diagnosis was 880 000/µl. 16 patients had an elevation of the serum creatinin at diagnosis, which deteriorated during the course of the disease. Bone marrow examinations were performed in 56 patients, histology in 48 patients, cytology in 29 patienst. In contrast to the clinical diagnosis the histological diagnosis was in 4 cases each polycythemia vera and myeloproliferative syndrome without further specifiction. 12 patients died thus far. The causes of death were thrombembolic complications in 9, acute leukemia in 2 patients, in 1 patient the cause of death is not known. 10 years after diagnosis 61% of the patients are still alive. It appears that ET is a more important risk factor for the disturbances of the micro- and marcrocirculation than has been recognized until now. ET is, if thrombembolic complications are avoided, a disease with a relatively benign course.
Abkürzungsverzeichnis ET essentielle Thromobozythämie - PRT persistierende reaktive Thombozytose - PV Polyzythämia vera - CML chronisch myeloische Leukämie - MF Myelofibrose - CMPE chronische myeloproliferative Erkrankung unklarer Zuordnung - MM megakaryozytäre Myelose - ALP alkalische Leukozytenphosphatase - Hb Hämoglobin Herrn Prof. Dr. N. Zöllner zum 65. Geburtstag gewidmet 相似文献
Abkürzungsverzeichnis ET essentielle Thromobozythämie - PRT persistierende reaktive Thombozytose - PV Polyzythämia vera - CML chronisch myeloische Leukämie - MF Myelofibrose - CMPE chronische myeloproliferative Erkrankung unklarer Zuordnung - MM megakaryozytäre Myelose - ALP alkalische Leukozytenphosphatase - Hb Hämoglobin Herrn Prof. Dr. N. Zöllner zum 65. Geburtstag gewidmet 相似文献