全文获取类型
收费全文 | 1267篇 |
免费 | 57篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 23篇 |
妇产科学 | 30篇 |
基础医学 | 187篇 |
口腔科学 | 3篇 |
临床医学 | 90篇 |
内科学 | 403篇 |
皮肤病学 | 9篇 |
神经病学 | 114篇 |
特种医学 | 36篇 |
外科学 | 127篇 |
综合类 | 7篇 |
预防医学 | 57篇 |
眼科学 | 4篇 |
药学 | 148篇 |
中国医学 | 3篇 |
肿瘤学 | 64篇 |
出版年
2023年 | 15篇 |
2022年 | 44篇 |
2021年 | 70篇 |
2020年 | 24篇 |
2019年 | 32篇 |
2018年 | 35篇 |
2017年 | 28篇 |
2016年 | 28篇 |
2015年 | 41篇 |
2014年 | 52篇 |
2013年 | 58篇 |
2012年 | 118篇 |
2011年 | 122篇 |
2010年 | 50篇 |
2009年 | 43篇 |
2008年 | 83篇 |
2007年 | 81篇 |
2006年 | 66篇 |
2005年 | 80篇 |
2004年 | 55篇 |
2003年 | 64篇 |
2002年 | 35篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 9篇 |
1997年 | 4篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1978年 | 2篇 |
1977年 | 5篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1971年 | 3篇 |
1967年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1937年 | 1篇 |
排序方式: 共有1328条查询结果,搜索用时 15 毫秒
101.
We investigated the dose-response relationship of protection by creatine against ischemic damage, and we asked whether or not such protection may be observed in invertebrate neurons that might provide a simpler experimental model. Rat isolated pyramidal neurons from the CA3 region of hippocampus subjected to ischemia ("in vitro ischemia") showed anoxic depolarization (AD) after 3-7 min of incubation in anoxic medium. Membrane potential (MP) was reduced 25-78% from preanoxic value. Inward current was decreased by an average 49%. Supplementation with creatine protected against these changes, with 1 mM being the minimal effective concentration, 2 mM providing a near-maximal protection, a maximal effect being obtained with 5 mM creatine. No additional protection was provided by up to 20 mM creatine. Isolated giant neurons of Lymnaea stagnalis showed a similar response to in vitro ischemia. However, a clear seasonal dependence of sensitivity of these cells was detected. In cells obtained during summertime (May-August), AD latency ranged from 3 to 10 min; during wintertime (December-March), this response did not occur even after 25-50 min. The addition of creatine to the medium did not cause changes in AD latency, probably because these neurons rely on a phosphoarginine/arginine energy system. However, treatment of the cells, harvested during summertime, with 2 mM arginine did provide clear protection against anoxic-aglycaemic changes. Summing up, besides confirming previous findings on creatine protection in mammalian neurons, we (1) better characterized their dose-response relationship and extended the findings to the CA3 region and to isolated neurons, (2) found that invertebrate neurons are not protected by creatine but by arginine supplementation and (3) reported a novel mechanism of seasonal dependence in sensitivity of in vitro ischemia by invertebrate neurons. 相似文献
102.
Rationale Low platelet monoamine oxidase (MAO) activity is associated with problem drinking and other deviant behaviors. Since the majority of alcohol abusers are smokers, and tobacco smoke has a direct inhibitory effect on the enzyme, these associations may not be meaningful.Objective The authors compared platelet MAO activity and impulsivity in police-referred subjects caught driving while intoxicated and in control subjects, controlling for smoking.Methods Platelet MAO activity was measured radioenzymatically and impulsivity scores obtained from questionnaires. Smoking status was self-reported.Results Subjects caught driving while intoxicated had significantly higher dysfunctional impulsivity and lower platelet MAO activity than control subjects. This difference in platelet MAO activity between the two groups was significant in non-smokers and ex-smokers.Conclusions These findings demonstrate that platelet MAO activity is lower in subjects with socially deviant behavior, and the association of low platelet MAO and problem drinking is not an artifact of smoking. 相似文献
103.
Giwercman A Lundin KB Eberhard J Ståhl O Cwikiel M Cavallin-Ståhl E Giwercman YL 《European journal of cancer (Oxford, England : 1990)》2004,40(14):2152-2158
Sex hormones and/or gonadotropins may play a crucial role in the development of testicular germ cell cancer (TGCC). A direct link between this malignancy and endocrine factors has not been confirmed. We tested whether CAG and GGN repeats of the androgen receptor gene (AR) play a role in the aetiology or pathogenesis of TGCC. Eighty-three TGCC patients and 220 controls were included. Mean CAG or GGN lengths did not differ between the TGCC cases and controls. The proportion of males with CAG lengths above 25, indicative of reduced androgen sensitivity, was significantly lower among patients with pure seminomas and in the combined group of seminomas and mixed tumours compared with non-seminomas and controls. The median CAG length was higher if the tumour was metastasing at diagnosis. This is the first study showing an association between the AR polymorphism and histological type as well as the progression rate of TGCC. 相似文献
104.
Łukaszewicz R Bednarz B Chamiec T Maciejewski P Górecki A 《Kardiologia polska》2002,57(10):313-20; discussion 321
BACKGROUND: Acute coronary syndrome (ACS) carries the risk of death due to electrical or haemodynamical disturbances. Thus, rapid in-hospital treatment is necessary. To achieve this, a patient, his family and his physician should correctly diagnose ACS, based mainly on clinical symptoms. AIM: To assess the symptomatology of ACS and to establish whether modern management of ischaemic heart disease did not change ACS clinical characteristics. METHODS: The study group consisted of 156 consecutive patients (96 males, mean age 65+/-15 years) admitted to hospital due to ACS. Physicians prospectively filled in a questionnaire addressing ACS symptomatology, including chest pain characteristics and clinical symptoms of painless ACS. RESULTS: Retrosternal chest pain was present in 119 (76%) patients, six (4%) patients had pain localised outside thorax (jaws or epigastric region) whereas 31 (20%) patients had painless ACS. In the latter group the most frequent symptoms were dyspnea and marked weakness. CONCLUSIONS: Chest pain remains the most frequent symptom of ACS and its prevalence is similar to that previously described in literature. Almost a quarter of patients have painless ACS; in those patients other intensive and sudden symptoms may suggest ACS. 相似文献
105.
Bouloux PM Nieschlag E Burger HG Skakkebaek NE Wu FC Handelsman DJ Baker GH Ochsenkuehn R Syska A McLachlan RI Giwercman A Conway AJ Turner L van Kuijk JH Voortman G 《Journal of andrology》2003,24(4):604-611
A multicenter, open-label, randomized efficacy and safety study was performed with combined human chorionic gonadotropin (hCG) and recombinant follicle-stimulating hormone (recFSH) (Puregon(R)) treatment to induce spermatogenesis in hypogonadotropic hypogonadal male patients. Patients were pretreated for 16 weeks with hCG to normalize testosterone levels. A total of 30 of 49 (61%) subjects had normalized testosterone levels but were still azoospermic after the hCG-alone phase. These patients were randomized into 2 treatment schemes with recFSH (2 x 225 IU recFSH per week [group A] or 3 x 150 IU recFSH per week [group B]), in combination with hCG for a period of 48 weeks. Total testosterone increased during the hCG-alone period from 1.08 and 1.22 ng/mL to 6.26 and 4.52 ng/mL for groups A and B, respectively. Combined gonadotropin treatment was effective in inducing spermatogenesis (sperm count >/=1 x 10(6)/mL) in 14 of 30 subjects (47%) and this was achieved after a median duration of treatment of approximately 5.5 months. Treatment time necessary for first sperm cells to appear in the ejaculate was related to the initial testicular volume. Subjects with a history of maldescended testes (11 of 30 subjects, 37%) showed a lower mean response to treatment as indicated by the relatively lower number of subjects reaching levels of at least 1 x 10(6) sperm cells per milliliter. Combined testicular volume increased during combined gonadotropin treatment from 11.4 to 24.0 mL. Although subjects with a history of maldescended testes had a lower starting testicular volume, subjects with and without a history of maldescended testes showed approximately the same relative increase in testicular volume. Total testosterone levels showed only a minor further increase during the combined gonadotropin treatment period. In conclusion, a weekly dose of 450 IU (3 x 150 IU or 2 x 225 IU) recFSH, in addition to hCG, was able to induce spermatogenesis in many hypogonadotropic azoospermic men who failed to respond to treatment with hCG alone. 相似文献
106.
Quality of Life Improvement after Videothoracoscopic Splanchnicectomy in Chronic Pancreatitis Patients: Case Control Study 总被引:3,自引:1,他引:2
Makarewicz W Stefaniak T Kossakowska M Basiński A Suchorzewski M Stanek A Gruca ZB 《World journal of surgery》2003,27(8):906-911
The authors report on the effectiveness of videothoracoscopic splanchnicectomy (VSPL) as a method of pain treatment in patients with chronic pancreatitis (CP). A minimally invasive technique, VSPL is used in CP as an alternative method of pain treatment. The aim of the investigation was to evaluate by a prospective, semirandomized case-control study the influence of VSPL on the quality of life and the level of pain suffered by patients with CP. The study groups consisted of 32 patients who underwent VSPL between March 2000 and January 2001 and a control group of 32 CP patients who received conservative treatment. The effect of the therapy on subjective pain measures and multiparametric quality of life was measured before VSPL and throughout the first year thereafter. In the follow-up period there was a significant decrease in intensity of pain and an improvement in the quality of life of the patients—most significantly concerning emotional well-being and functioning in everyday life. We conclude that the VSPL is a safe, effective, and minimally invasive procedure and recommend that it be used in such cases. 相似文献
107.
Angelucci F Aloe L Jiménez-Vasquez P Mathé AA 《The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP)》2003,6(3):225-231
Nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) are proteins involved in neuronal survival and plasticity of dopaminergic, cholinergic and serotonergic neurons in the central nervous system. Since decreased size and impaired function of some neuronal populations may be relevant in depression it has been hypothesized that these molecules may have a functional role in the pathophysiology as well as treatment of depression. Using an animal model of depression, the Flinders Sensitive Line (FSL) rats and their controls, the Flinders Resistant Line (FRL), we investigated the effects of chronic lithium treatment on brain NGF, BDNF and GDNF. Lithium was administered as food supplementation during 6 wk. NGF, BDNF and GDNF measurements were performed by enzyme-linked immunosorbent assay (ELISA). Lithium altered the brain concentrations of neurotrophic factors in the hippocampus, frontal cortex, occipital cortex and striatum. Moreover, the changes were different in the two rat strains. Our data support the notion that neurotrophic factors play a role in depression and in the mechanism of the action of lithium. 相似文献
108.
Recombinant human TSH-aided radioiodine treatment of advanced differentiated thyroid carcinoma: a single-centre study of 54 patients 总被引:1,自引:0,他引:1
Jarzab B Handkiewicz-Junak D Roskosz J Puch Z Wygoda Z Kukulska A Jurecka-Lubieniecka B Hasse-Lazar K Turska M Zajusz A 《European journal of nuclear medicine and molecular imaging》2003,30(8):1077-1086
We sought to evaluate the efficacy, biochemical effects, safety and outcome of recombinant human thyroid-stimulating hormone (rhTSH) as an adjunct to radioiodine treatment of advanced differentiated thyroid carcinoma (DTC). We also sought to determine whether rhTSH is useful as an adjunct to radioiodine treatment following isotretinoin re-differentiation therapy of DTC metastases that have lost function. Therefore, in 54 consecutive patients who had retained bulky metastatic and/or locoregional lesions of DTC despite the exhaustion of other therapeutic options, we gave one to four courses of two consecutive daily intramuscular injections of rhTSH, 0.9 mg, followed by a therapeutic activity of (131)I per os on day 3. Fifty patients had received prior radioiodine treatment aided by l-thyroxine (T(4)) withdrawal. We included in the study 23 patients who had received a trial of isotretinoin therapy for re-differentiation of confirmed de-differentiated metastases. In a blinded, within-patient comparison of post-therapy whole-body scans after the first rhTSH-aided and latest withdrawal-aided treatments in patients with functional metastases at baseline, 18 of 27 (67%) scan pairs were concordant, four (15%) were discordant in favour of the rhTSH-aided scan and five (19%) were discordant in favour of the withdrawal-aided scan. In total, 37 (74%) of 50 paired scans were concordant, eight (16%) favoured rhTSH and five (10%) favoured withdrawal. All differences appeared to be attributable to clinical causes, not to any difference between endogenous and exogenous TSH stimulation. Reflecting the biochemical activity of rhTSH and the release of thyroglobulin (Tg) due to tumour destruction, median serum Tg concentration rose approximately fourfold between baseline and day 6 of the rhTSH-aided treatment course. rhTSH was well tolerated, with mostly minor, transient toxicity, except for neck oedema in three patients with neck infiltrates and pathological spine fracture in one patient with a large vertebral metastasis. At 6 months, complete response occurred in one (2%), partial response in 12 (26%) and disease stabilisation in 19 (40%) of 47 evaluable patients. The rate of complete + partial response was 41% and that of disease stabilisation, 30%, in the 27 evaluable patients with functional metastases at baseline; the corresponding rates were 10% and 55% in the 20 evaluable patients with non-functional metastases at baseline. Although within-patient comparison of early outcome after both modalities is limited by a significantly greater median number of courses and a greater median cumulative activity of radioiodine given under withdrawal, response to rhTSH-aided and withdrawal-aided treatment was similar in 23 (52%) of 44 evaluable patients, superior with rhTSH in 12 (27%) and superior with withdrawal in seven (16%). In two patients, a superior response was obtained after isotretinoin pretreatment and rhTSH and attributed to re-differentiation therapy. In conclusion, our study provides preliminary evidence that rhTSH safely and effectively aids radioiodine treatment of advanced DTC, and does so to an at least equivalent degree as does T(4) withdrawal. 相似文献
109.
Sacha T Hochhaus A Hanfstein B Müller MC Rudzki Z Czopek J Wolska-Smoleń T Czekalska S Salamanchuk Z Jakóbczyk M Skotnicki AB 《Leukemia research》2003,27(12):1163-1166
Imatinib mesylate (STI571) is a major therapeutic advance for the management of chronic myeloid leukaemia (CML), however, a proportion of patients are refractory to it, particularly those in more advanced phases of CML. Different mechanisms of resistance to imatinib are suggested, including point mutations within ABL-kinase domains. A point mutation leading to substitution at the ATP binding site of ABL-kinase and insensitivity to imatinib was detected in our patient treated with imatinib, who progressed to blast crisis. Additionally, clonal evolution could lead to BCR–ABL-independent proliferation. Early detection of ABL-kinase mutation could predict the progression of CML treated with imatinib. 相似文献
110.
A series of MDP (muramyldipeptide) or nor-MDP (normuramyldipeptide) analogues modified at the C-terminus post of the molecule by a formation of an ester bond between the carboxylic group of isoglutamine and the hydroxyl function of the respective derivatives of 4-carboxamide-acridine/9-acridone or 1-nitro-9-hydroxyalkylaminoacridines were synthesized as potential anticancer agents. The compounds O-(1-O-benzyl-N-acetyl-muramyl-l-alanyl-d-gamma-isoglutaminyl)-9-(ethylamino)-1-nitroacridine ester 3j and O-(1-O-benzyl-N-acetyl-muramyl-l-alanyl-d-gamma-isoglutaminyl)-9-propylamino-1-nitroacridine ester 3k exhibited high in vitro cytotoxic activity against a panel of human cell lines, prostate cancer and AIDS-related lymphoma (ARL). Analogue 3j was also active in vivo in the hollow fiber assay. Antitumor activity of both compounds were tested in vivo against difference human tumor xenograft, but only analogue 3k showed in vivo activity against sc UACC-62 melanoma in mice. 相似文献