全文获取类型
收费全文 | 16382篇 |
免费 | 1409篇 |
国内免费 | 51篇 |
专业分类
耳鼻咽喉 | 138篇 |
儿科学 | 596篇 |
妇产科学 | 320篇 |
基础医学 | 1966篇 |
口腔科学 | 272篇 |
临床医学 | 1908篇 |
内科学 | 3057篇 |
皮肤病学 | 156篇 |
神经病学 | 1562篇 |
特种医学 | 568篇 |
外科学 | 2257篇 |
综合类 | 664篇 |
一般理论 | 22篇 |
预防医学 | 1757篇 |
眼科学 | 410篇 |
药学 | 1173篇 |
中国医学 | 11篇 |
肿瘤学 | 1005篇 |
出版年
2023年 | 84篇 |
2022年 | 176篇 |
2021年 | 317篇 |
2020年 | 202篇 |
2019年 | 342篇 |
2018年 | 405篇 |
2017年 | 286篇 |
2016年 | 333篇 |
2015年 | 356篇 |
2014年 | 456篇 |
2013年 | 645篇 |
2012年 | 1056篇 |
2011年 | 1074篇 |
2010年 | 561篇 |
2009年 | 465篇 |
2008年 | 887篇 |
2007年 | 926篇 |
2006年 | 915篇 |
2005年 | 858篇 |
2004年 | 799篇 |
2003年 | 686篇 |
2002年 | 715篇 |
2001年 | 371篇 |
2000年 | 354篇 |
1999年 | 322篇 |
1998年 | 183篇 |
1997年 | 139篇 |
1996年 | 144篇 |
1995年 | 108篇 |
1994年 | 128篇 |
1993年 | 138篇 |
1992年 | 287篇 |
1991年 | 248篇 |
1990年 | 208篇 |
1989年 | 196篇 |
1988年 | 187篇 |
1987年 | 188篇 |
1986年 | 176篇 |
1985年 | 155篇 |
1984年 | 127篇 |
1983年 | 102篇 |
1982年 | 87篇 |
1981年 | 87篇 |
1980年 | 99篇 |
1979年 | 85篇 |
1978年 | 82篇 |
1976年 | 86篇 |
1974年 | 80篇 |
1973年 | 97篇 |
1972年 | 89篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Late-onset and Recurrent Neonatal Group B Streptococcal Disease Associated with Breast-milk Transmission 总被引:2,自引:0,他引:2
Michael Kotiw Gwang W. Zhang Grant Daggard Elizabeth Reiss-Levy John W. Tapsall Andrew Numa 《Pediatric and developmental pathology》2003,6(3):251-256
The purpose of the study was to determine the epidemiological relationships in three unrelated cases of neonatal late-onset Group B streptococcal (GBS) disease and maternal breast-milk infection with GBS. All deliveries were by cesarean section; case 1 was at term, and cases 2 and 3 were at 32- and 33-wk gestation, respectively. Case 1 relates to a mother with clinical mastitis and recurrent GBS infection in a 20-day-old male infant. Following antibiotic therapy and cessation of breast-feeding, the infant recovered without sequelae. Case 2 refers to a mother with clinical mastitis and the occurrence of late-onset GBS disease in 5-wk-old male twins. Despite intervention, one infant died and the second became ill. Following antibiotic therapy and cessation of breast-feeding, the surviving infant recovered without sequelae. Case 3 refers to a mother with sub-clinical mastitis and late-onset GBS infection occurring in a 6-day-old female twin. Following intervention, the infant recovered but suffered a bilateral thalamic infarction resulting in developmental delay and a severe seizure disorder. Following recovery of GBS from an inapparent mastitis and cessation of breast-feeding, the second infant remained well. Blood cultures from all affected infants and maternal breast milk were positive for GBS. Epidemiological relationships between neonatal- and maternal-derived GBS isolates were confirmed by a random amplified polymorphic DNA polymerase chain reaction assay (RAPD-PCR). This study is significant in that it has demonstrated that maternal milk (in cases of either clinical or sub-clinical mastitis) can be a potential source of infection resulting in either late-onset or recurrent neonatal GBS disease. 相似文献
12.
The cellular complexity of the brain (some estimate that there are up to 103 different cell types) is exceeded by the synaptic complexity, with each of the ∼1011 neurons in the brain having around 103 –104 synapses. Proteomic studies of the synapse have revealed that the postsynaptic density is the most complex multiprotein structure yet identified, with ∼103 different proteins. Such studies, however, use brain tissue with many different regions and therefore different cell types, and there is clear potential for heterogeneity of protein content at different synapses within and between brain regions. Although large-scale mRNA-based assays are in progress to map this sort of complexity at the cellular level, and indeed all brain-expressed genes, analysis of protein distribution (at synapses and other structures) is still in the very early stages. We review existing large-scale protein expression studies and the specific technical obstacles that need to be overcome before applying the scaling used in nucleic acid based approaches. 相似文献
13.
Alan and Marcia Emery have given the reader a book of considerableerudition and insight into the relationship between medicineand society over the past 2000 years. Many will get great pleasuresimply from dipping in and out of this book. Their choice ofover 50 images of 相似文献
14.
EFNS Guidelines on diagnosis and treatment of brain metastases: report of an EFNS Task Force 总被引:2,自引:0,他引:2
R. Soffietti P. Cornu J. Y. Delattre R. Grant F. Graus W. Grisold J. Heimans J. Hildebrand P. Hoskin M. Kalljo P. Krauseneck C. Marosi T. Siegal C. Vecht 《European journal of neurology》2006,13(7):674-681
The objectives have been to establish evidence-based guidelines and identify controversies regarding the management of patients with brain metastases. The collection of scientific data was obtained by consulting the Cochrane Library, bibliographic databases, overview papers and previous guidelines from scientific societies and organizations. A tissue diagnosis is necessary when the primary tumor is unknown or the aspect on computed tomography/magnetic resonance imaging is atypical. Dexamethasone is the corticosteroid of choice for cerebral edema. Anticonvulsants should not be prescribed prophylactically. Surgery should be considered in patients with up to three brain metastases, being effective in prolonging survival when the systemic disease is absent/controlled and the performance status is high. Stereotactic radiosurgery should be considered in patients with metastases of 3–3.5 cm of maximum diameter. Whole-brain radiotherapy (WBRT) after surgery or radiosurgery is debated: in case of absent/controlled systemic cancer and Karnofsky Performance score of 70 or more, one can either withhold initial WBRT or deliver early WBRT with conventional fractionation to avoid late neurotoxicity. WBRT alone is the treatment of choice for patients with single or multiple brain metastases not amenable to surgery or radiosurgery. Chemotherapy may be the initial treatment for patients with brain metastases from chemosensitive tumors. 相似文献
15.
Evaluation of renal transplant dysfunction by duplex Doppler sonography: a prospective study and review of the literature 总被引:5,自引:0,他引:5
R R Perrella A J Duerinckx F N Tessler G M Danovitch A Wilkinson S Gonzalez A H Cohen E G Grant 《American journal of kidney diseases》1990,15(6):544-550
A disconcertingly wide variation exists in the literature as to the accuracy of duplex Doppler sonography in the detection of acute renal transplant rejection. Sensitivities range from 9% to 76%. In an attempt to explain the disparity of results, we undertook a double-blind prospective study of the accuracy of duplex Doppler ultrasound in the detection of acute rejection in renal transplants. We scanned 49 consecutive patients with a total of 65 biopsies; 46 biopsies in 33 consecutive patients were included in our study. In our population, the prevalence of acute rejection was 61% (28/46). Using a resistive index (RI) cutoff of greater than 0.90 based on the main renal artery flow pattern, the sensitivity of our test was 43%, with a 67% specificity. The positive predictive value was 67%. Our results are contrasted and compared with the published data from other groups in a critical survey of the literature. We conclude that duplex Doppler sonography alone is inadequate to evaluate acute rejection in renal transplants. 相似文献
16.
17.
18.
Effect of the beta-adrenoceptor agonist clenbuterol and phytohaemagglutinin on growth, protein synthesis and polyamine metabolism of tissues of the rat. 下载免费PDF全文
S. Bardocz D. S. Brown G. Grant A. Pusztai J. C. Stewart R. M. Palmer 《British journal of pharmacology》1992,106(2):476-482
1. The kidney bean lectin, phytohaemagglutinin (PHA), induced a marked atrophy of skeletal muscle which was evident from the changes in tissue composition (protein, RNA, DNA and polyamine content) and from the reduction in weight and protein synthesis of hind leg muscles of rats fed on kidney bean-diets for four days. The beta-adrenoceptor agonist, clenbuterol, induced skeletal muscle hypertrophy by transiently stimulating protein synthesis. As a consequence, the muscle loss caused by a short exposure to PHA was, in part, ameliorated by clenbuterol treatment. 2. Cardiac muscle was affected to a lesser extent than skeletal muscle by both clenbuterol and the lectin. However, there was evidence that protein synthesis in heart was reduced by PHA. 3. PHA had opposite effects on the gut, the lectin-induced hyperplasia of the jejunum was accompanied by a large increase in protein synthesis. Clenbuterol alone had no effect on the jejunum whereas a combination of PHA and clenbuterol appeared to exacerbate the effect of the lectin on gut. 4. Both the lectin-induced gut growth and the hypertrophy of skeletal muscle caused by clenbuterol were preceded by the accumulation of polyamines in the respective tissues. Of particular note was the observation that a significant increase in the proportion of the intraperitoneally injected 14C-labelled spermidine or putrescine taken up by the growing tissues could be detected by the second day. Therefore, the measurement of uptake of labelled polyamines may be used as a sensitive indicator of early alterations in tissue metabolism. 相似文献
19.
20.