全文获取类型
收费全文 | 111148篇 |
免费 | 6746篇 |
国内免费 | 653篇 |
专业分类
耳鼻咽喉 | 1087篇 |
儿科学 | 3609篇 |
妇产科学 | 2558篇 |
基础医学 | 16041篇 |
口腔科学 | 4007篇 |
临床医学 | 10110篇 |
内科学 | 24879篇 |
皮肤病学 | 2746篇 |
神经病学 | 10859篇 |
特种医学 | 2697篇 |
外国民族医学 | 1篇 |
外科学 | 10425篇 |
综合类 | 493篇 |
一般理论 | 50篇 |
预防医学 | 11097篇 |
眼科学 | 1761篇 |
药学 | 7721篇 |
中国医学 | 422篇 |
肿瘤学 | 7984篇 |
出版年
2024年 | 126篇 |
2023年 | 1049篇 |
2022年 | 2254篇 |
2021年 | 3743篇 |
2020年 | 2346篇 |
2019年 | 3174篇 |
2018年 | 3605篇 |
2017年 | 2740篇 |
2016年 | 3195篇 |
2015年 | 3518篇 |
2014年 | 4632篇 |
2013年 | 6086篇 |
2012年 | 9230篇 |
2011年 | 9586篇 |
2010年 | 5216篇 |
2009年 | 4404篇 |
2008年 | 7613篇 |
2007年 | 7622篇 |
2006年 | 6972篇 |
2005年 | 6511篇 |
2004年 | 5861篇 |
2003年 | 5194篇 |
2002年 | 4702篇 |
2001年 | 669篇 |
2000年 | 501篇 |
1999年 | 702篇 |
1998年 | 825篇 |
1997年 | 686篇 |
1996年 | 578篇 |
1995年 | 499篇 |
1994年 | 464篇 |
1993年 | 373篇 |
1992年 | 379篇 |
1991年 | 270篇 |
1990年 | 301篇 |
1989年 | 268篇 |
1988年 | 243篇 |
1987年 | 211篇 |
1986年 | 232篇 |
1985年 | 169篇 |
1984年 | 183篇 |
1983年 | 166篇 |
1982年 | 180篇 |
1981年 | 141篇 |
1980年 | 135篇 |
1979年 | 111篇 |
1978年 | 103篇 |
1977年 | 90篇 |
1976年 | 76篇 |
1974年 | 82篇 |
排序方式: 共有10000条查询结果,搜索用时 20 毫秒
991.
Maria G. Cattell 《Journal of cross-cultural gerontology》1994,9(2):157-178
Among Abaluyia of Kenya relative age (seniority) structures relationships hierarchically among co-wives, siblings and females of different generations. Ambiguous equality and affectionate informality in grandmother-granddaughter relationships mute the hierarchical implications of their different age and generation statuses. This facilitates grandmothers' educational roles although, as grandmothers say, Nowadays it isn't easy to advise the young. Increased physical, cognitive and experiential distances between these generations resulted from radical changes in the female lifecourse associated with modernization and delocalization. Nevertheless, reciprocal exchanges continue. Granddaughters are also intermediaries in exchanges between older women and their adult daughters. Some grandmothers are denied the companionship and assistance of granddaughters caught in the middle of mother-in-law/daughter-in-law conflicts. Many grandmothers assume parental responsibilities as they deal with the modern problem of daughters' premarital pregnancies. All in all, these intergenerational relationships reveal both cultural persistence and the effects of social change, and continue to have instrumental and expressive value for both grandmothers and granddaughters. 相似文献
992.
993.
Sex selection may be inadvertently performed in in-vitro fertilization--embryo transfer programmes 总被引:3,自引:2,他引:1
Tarin Juan J.; Bernabeu Rafael; Baviera Amparo; Bonada Maria; Cano Antonio 《Human reproduction (Oxford, England)》1995,10(11):2992-2998
The present study aims to ascertain whether sex selection maybe inadvertently performed in human in-vitro fertilization (IVF)and embryo transfer (IVF-embryo transfer) programmes when selectingfor high quality embryos (those with the fastest cleaving ratesand/or the best morphology) at the fresh transfer cycle. Allpatients entering into the study were treated with gonadotrophinsafter pituitary suppression with gonadotrophin-releasing hormoneagonists (GnRHa) and had intrauterine embryo transfer on day2 post-insemination. These patients were retrospectively dividedinto three groups according to whether the difference in meannumber of cells between embryos transferred and all embryosavailable for transfer in a given cycle was less than (negativeselection), equal to (no selection) or greater (positive selection)than zero. In cycles resulting in singleton births, the sexratio of the resulting babies was significantly (P 0.005) shiftedtoward the female (88.8%) and to the male (90.0%) in the negativeand positive selection groups respectively. No shift in sexratio was observed in cycles resulting in multiple births. Maternalage was another independent factor affecting sex ratio at birth.Sex ratio was significantly (P 0.05) skewed in favour of males(62.7%) and females (71.4%) in women <35 and 235 years ofage respectively. Maternal age, number of embryos transferredand the event of selecting or not selecting the slowest cleavingembryos for transfer were entered automatically in a three-groupdiscriminant model for distinguishing cycles resulting in onlyboys, both boys and girls, and only girls. These data suggestthat (i) sex selection may be inadvertently performed in IVF-embryotransfer programmes when selecting for high quality embryosat the fresh transfer cycles; (ii) human endometria may be favourable,indifferent or hostile to either fast cleaving or slow cleavingembryos depending on maternal age; and (iii) naturalsex selection may be performed for social, psychological ormedical reasons. 相似文献
994.
Athanasios Zahariou Maria Karamouti George Karagiannis Polyanthi Papaioannou 《Journal of neurology》1995,242(Z2):S61-S62
Poster Session 1
Child neurology 相似文献995.
Background: In the past 4 years we performed operations on 90 patients who suffered from morbid obesity. Five different operative
techniques were available, vertical banded gastroplasty (VBG), silastic ring vertical gastroplasty (SRVG), gastric banding
operation, adjustable silicone gastric banding (ASGB) and biliopancreatic diversion (BPD). Methods: Two of these operations
were mainly utilized. The ASGB was done routinely. The SRVG was used particularly for patients with hiatal hernia. Only one
patient, who had a deformed pylorus, underwent the BPD. Results: Eleven patients had to be reoperated due to complications
after the first operation of gastric restriction. They were divided into three groups depending on the type of complication:
reoperation due to lack of compliance, due to technical failure, or due to other complications. In the last group we observed
three patients with band perforation into the stomach without epigastric pain. This complication has, to our knowledge, only
been described in very few cases. Conclusion: In some patients it remained difficult to reach adequate compliance, although
we kept close contact with them after the operation. We do not yet know the reasons for the band perforation observed in three
patients. 相似文献
996.
Dr. Maurizio Vaglini MD Dr. Filiberto Belli MD Mario Santinami MD Flavio Arienti MD Giorgio Parmiani MD Laura Persiani MD Nicola Santoro MD Maria Grazia Inglese MD Fortunato D'Elia MD Natale Cascinelli MD 《Annals of surgical oncology》1995,2(1):61-70
Background: Therapies of advanced melanoma patients with interleukin-2 (IL-2) and cytotoxic lymphocytes have produced interesting results, but a larger diffusion of these treatments is limited by the severe side effects due to IL-2 systemic infusion. A strictly regional administration of IL-2 and cells by an isolation perfusion (IP) in extracorporeal circulation (ECC) for the treatment of regional melanoma metastases could improve tolerability and efficacy of this specific modality of immunotherapy.
Methods: Ten patients were submitted to adoptive immunotherapy with IL-2 and lymphokine-activated killer (LAK) cells by IP in ECC. The schedule of treatment included the first course of a 5-day systemic administration of IL-2 (Proleukin, EuroCetus 9–12 × 106 IU/M2/day continuous infusion); autologous LAK cells were obtained via leukapheresis and after in vitro activation were given (range 8–28 × 109) along with IL-2 (120-2,400 IU/ml of perfusion priming) to the affected limb by IP; IL-2 (9–12×106 IU/m2/day) was also administered by systemic continuous infusion for 5 days starting on the day after IP.
Results: All patients concluded the treatment without any major local or systemic toxicities. Clinical responses included one complete and six partial remissions; three patients had stable disease. All patients are alive. Follow-up after IP ranged from 12 to 35 months (median: 22). The analysis of circulating lymphocytes revealed the rapid disappearance of LAK cells, suggesting their extravasation and/or endothelial adhesion in perfused tissues.
Conclusions: IP with IL-2 and LAK cells is a new approach for the treatment of in-transit metastases due to cutaneous melanoma. The treatment appears to be feasible and reliable. Further biological and immunological studies should permit amelioration of the present modality of treatment. 相似文献
997.
Friedman D Cuneo S Valenzano M Marinari GM Adami GF Gianetta E Traverso E Scopinaro N 《Obesity surgery》1995,5(3):308-313
Background: 239 pregnancies occurred in 1136 women who had undergone biliopancreatic diversion (BPD). Methods: There were
73 abortions, and 14 pregnancies are presently in their course. The 152 term pregnancies (six twins) occurred in 129 women
2-173 months (mean 42.7) after BPD. Mean age and current excess weight were 31.4 years (20-42) and 29.1% (-6.9-78.2), and
mean excess weight loss was 72.9% (30.4-110.5). Results: Mean weight gain during pregnancy was 6.2 kg (-21-25). In 32 patients
(21%), parenteral nutritional support was needed. In all the other patients (79%), the usual supplementations were given.
Of the newborns, 122 were delivered at term (84.7%) with a mean weight of 2842.4 g (1760-4600 g) and a mean length of 48.5
cm (43-59 cm), while the 22 preterm babies (15.3%) weighed 2151.1 g (1400-3850 g) and had a length of 44.6 cm (33-56 cm).
Forty infants (27.8%) were small for gestational age but 17 of them weighed more than 2500 g. Eleven twins (one abortion at
26th week) were also delivered, with a mean weight of 2088.6 g (1200-3100 g) and a mean length of 45.6 cm (35-50 cm). Delivery
was spontaneous in 85 instances (56%), while vacuum extractor was used in one, and 66 cesarean sections were performed. There
were two birth malformations, one infant died after surgery for meconium obstruction and two died from unknown causes. Of
the 129 women, 35 had been infertile before BPD. Conclusions: Disappearance of infertility and decrease of pregnancy risk
are to be considered among the beneficial effects of weight reduction following BPD. 相似文献
998.
Peter J. Theuvenet Zbigniew Dunajski Maria J. Peters Jan M. van Ree 《Brain topography》1999,11(4):305-313
Somatosensory evoked magnetic fields and electrical potentials were measured in eight patients with unilateral neuropathic pain. After median nerve stimulation on the painful side, the amplitudes of the evoked responses were enhanced 2 to 3 times at a latency of about 100 ms compared to the responses of the contralateral, unaffected side. After posterior tibial nerve stimulation an enhancement was found at latencies around 110 ms and 150 ms. The scalp distribution of the magnetic field at the latencies of abnormal responses was dipolar and the responses could be ascribed to a current dipole. Three (of the eight) patients underwent spinal cord stimulation (SCS) for their pain. The enhancement of the evoked responses to stimulation of the painful side decreased after spinal cord stimulation. After a long period of spinal cord stimulation only (e.g., a year) during which the patient reported to be pain free, these abnormal responses were no longer observed. 相似文献
999.
Differential influences of coping humor and humor bias on mood 总被引:1,自引:0,他引:1
The authors investigated relationships among sense of humor measured by a questionnaire, attentional bias toward humor measured by performance on a word-search task, and experimentally induced mood change through the use of sad and humorous cartoons. Mood was significantly altered in a negative direction after the sad cartoon. Coping humor, part of the sense of humor questionnaire, was associated with less negative mood ratings after the sad cartoon. In terms of main effects, only a modest change in mood was found after the humorous cartoon. Humor bias was associated with more positive mood ratings after the humorous cartoon. The authors suggest that coping humor serves a protective psychological function, helping screen the person from negative stimuli and, thus, from negative reactions. Attentional bias toward humor serves a different protective psychological function by helping the person focus on mood-enhancing stimuli in the environment. 相似文献
1000.
Computerized analysis of lesions in US images of the breast 总被引:1,自引:0,他引:1
Giger ML Al-Hallaq H Huo Z Moran C Wolverton DE Chan CW Zhong W 《Academic radiology》1999,6(11):665-674
RATIONALE AND OBJECTIVES: Breast sonography is not routinely used to distinguish benign from malignant solid masses because of considerable overlap in their sonographic appearances. The purpose of this study was to investigate the computerized analyses of breast lesions in ultrasonographic (US) images in order to ultimately aid in the task of discriminating between malignant and benign lesions. MATERIALS AND METHODS: Features related to lesion margin, shape, homogeneity (texture), and posterior acoustic attenuation pattern in US images of the breast were extracted and calculated. The study database contained 184 digitized US images from 58 patients with 78 lesions. Benign lesions were confirmed at biopsy or cyst aspiration or with image interpretation alone; malignant lesions were confirmed at biopsy. Performance of the various individual features and output from linear discriminant analysis in distinguishing benign from malignant lesions was studied by using receiver operating characteristic (ROC) analysis. RESULTS: At ROC analysis, the feature characterizing the margin yielded Az values (area under the ROC curve) of 0.85 and 0.75 in distinguishing between benign and malignant lesions for the entire database and for an "equivocal" database, respectively. The equivocal database contained lesions that had been proved to be benign or malignant at cyst aspiration or biopsy. Linear discriminant analysis round-robin runs yielded Az values of 0.94 and 0.87 in distinguishing benign from malignant lesions for the entire database and for the equivocal database, respectively. CONCLUSION: Computerized analysis of US images has the potential to increase the specificity of breast sonography. 相似文献