全文获取类型
收费全文 | 10131篇 |
免费 | 626篇 |
国内免费 | 75篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 216篇 |
妇产科学 | 177篇 |
基础医学 | 1096篇 |
口腔科学 | 208篇 |
临床医学 | 1082篇 |
内科学 | 2410篇 |
皮肤病学 | 169篇 |
神经病学 | 534篇 |
特种医学 | 254篇 |
外国民族医学 | 1篇 |
外科学 | 1805篇 |
综合类 | 263篇 |
现状与发展 | 1篇 |
一般理论 | 6篇 |
预防医学 | 673篇 |
眼科学 | 190篇 |
药学 | 953篇 |
中国医学 | 196篇 |
肿瘤学 | 542篇 |
出版年
2024年 | 17篇 |
2023年 | 196篇 |
2022年 | 567篇 |
2021年 | 720篇 |
2020年 | 427篇 |
2019年 | 518篇 |
2018年 | 518篇 |
2017年 | 318篇 |
2016年 | 355篇 |
2015年 | 386篇 |
2014年 | 461篇 |
2013年 | 575篇 |
2012年 | 870篇 |
2011年 | 785篇 |
2010年 | 410篇 |
2009年 | 359篇 |
2008年 | 556篇 |
2007年 | 535篇 |
2006年 | 450篇 |
2005年 | 407篇 |
2004年 | 337篇 |
2003年 | 325篇 |
2002年 | 172篇 |
2001年 | 78篇 |
2000年 | 60篇 |
1999年 | 51篇 |
1998年 | 35篇 |
1997年 | 27篇 |
1996年 | 22篇 |
1995年 | 13篇 |
1994年 | 19篇 |
1993年 | 21篇 |
1992年 | 25篇 |
1991年 | 20篇 |
1990年 | 15篇 |
1989年 | 15篇 |
1988年 | 22篇 |
1987年 | 15篇 |
1986年 | 7篇 |
1985年 | 15篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1982年 | 13篇 |
1981年 | 13篇 |
1980年 | 12篇 |
1979年 | 6篇 |
1978年 | 10篇 |
1977年 | 7篇 |
1975年 | 5篇 |
1972年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Elias N. Nasr Muhammad A. K. Bhatti Errol Warner 《Journal of the National Medical Association》1981,73(6):525-529
Five cases of duodenal injuries were treated in our hospital between January 1, 1975 and June 18, 1979. They belonged to the Class II and early Class III of duodenal injuries. They were treated with simple closure of the perforation in a single or double layer with external drainage. Only in one case were gastrojejunostomy and bilateral vagotomy added because the patient had a history of ulcer disease. The delay in operative treatment ranged between five and 48 hours. All responded well to the surgical treatment. In the instance of the longest operative delay, a purulent drainage occurred and it responded promptly to a selective antibiotic therapy. The average hospitalization stay was nine days for the patients operated upon early, whereas it was 15 days for the two delayed cases. No mortality was recorded. 相似文献
43.
Idrees M Gandhi C Betchen S Strauchen J King W Wolfe D 《Archives of pathology & laboratory medicine》2005,129(1):e11-e15
Peripheral primitive neuroectodermal tumors (pPNETs) are aggressive, poorly differentiated neoplasms that occur in children and young adults. These tumors are associated with a peak incidence in the second decade and a slight male preponderance. Recently, Ewing sarcoma and pPNET tumors have been proven to carry identical translocations, the most common being t(11;22)(q24;q12). Intracranial Ewing sarcoma/pPNETs have rarely been described in the literature. We studied a case of intracranial pPNET arising in the right cavernous sinus of a 46-year-old man. On imaging, the tumor had both sellar and suprasellar components and was centered within the right parasellar region. Histologically, the tumor was composed of intermediate to large cells with round to oval hyperchromatic nuclei with distinct nucleoli. The cells contained a moderate amount of slightly basophilic cytoplasm. The tumor was markedly fibrotic and had collagen bands surrounding both individual and groups of cells. A large immunohistochemical panel was positive only for CD99 and vimentin. Fluorescence in situ hybridization did not show translocations associated with Ewing sarcoma/pPNET. However, a small percentage of these tumors can be negative for this translocation. In these cases, histology and immunohistochemical techniques in the absence of an alternative diagnosis are the only tools available to establish the diagnosis. 相似文献
44.
Chromosomal aberrations and micronucleus frequency in nurses occupationally exposed to cytotoxic drugs 总被引:4,自引:1,他引:4
Anwar Wagida A.; Salama Somaia I.; Serafy Mostafa M.EI; Hemida Samia A.; Hafez Ahmed S. 《Mutagenesis》1994,9(4):315-317
In this study, we evaluated the effect of low level occupationalexposure of nurses in a medical oncology unit in Cairo, Egypt,to anticancer drugs. Twenty nurses who constantly handled thesedrugs and 20 controls, matched according to age and sex, wereexamined. Metaphase chromosomes were studied. Percentages ofmetaphases with chromosomal aberrations were significantly higher(P < 0.001) in the exposed group (6.1 ± 2.7) versusthe controls (2.6 ± 1.6). The detected chromosomal aberrationswere in the form of chromatid gaps, chromatid breaks and acentricfragments. Micronucleated peripheral blood lymphocytes werealso analyzed in cytochalasin B treated binucleated lymphocytes.There was significant increase in cells with micronuclei (P< 0.001) in nurses (10.05 ± 4.71) in comparison tothe matched control (5.42 ± 2.22) (P < 0.001). Nursesexposed to the cytotoxic drugs for 相似文献
45.
Magnié MN Bermon S Martin F Madany-Lounis M Suisse G Muhammad W Dolisi C 《Psychophysiology》2000,37(3):369-377
Electrophysiological effects of aerobic fitness and maximal aerobic exercise were investigated by comparing P300 and N400 before and after a maximal cycling test. Event-related potentials (ERPs) were obtained from 20 students divided into two matched groups defined by their aerobic fitness level (cyclists vs. sedentary subjects). The session of postexercise ERPs was performed immediately after body temperature and heart rate returned to preexercise values. At rest, no significant differences were observed in ERP parameters between cyclists and sedentary subjects. This finding argued against the hypothesis that ERP modifications may be directly assumed by aerobic fitness level. The postexercise session of ERPs showed a significant P300 amplitude increase and a significant P300 latency decrease in all subjects. Similarly, N400 effect increased significantly after the maximal exercise in all subjects. ERP changes were of the same magnitude in the two groups. The present study argues for a general arousing effect of maximal aerobic exercise, independently of the aerobic fitness level. 相似文献
46.
Peres EM Savasan S Cushing B Abella S Mohamed AN 《Cancer Genetics and Cytogenetics》2004,148(1):66-70
Cytogenetic analyses of 16 cases of Wilms tumor with abnormal karyotypes were reviewed, 15 cases of unilateral tumor and 1 bilateral. Three tumors exhibited an unfavorable histology (i.e., anaplastic changes); the rest fell into the favorable histology group. Of the 17 tumors with abnormal clonal aberrations, 9 tumors were hyperdiploid (53%), 7 had pseudodiploid karyotypes (41%), and 1 was hypodiploid (6%). The most common numerical aberrations in descending order of frequency were gain of chromosomes 12, 8, and 6 and loss of chromosome 16. Structural rearrangements mostly involved chromosome 1, followed by chromosomes 7, 14, and 17. Clustering of breaks around 1p22 approximately p31-->pter resulting in partial loss of 1p was the most frequent structural aberration. Additionally, i(7q) was observed as a sole abnormality in two tumors and a 7p translocation in two other tumors. Two other recurrent abnormalities were a partial deletion of 14q, seen in three tumors, and complete loss of chromosome 14 in one tumor. All three Wilms tumors with unfavorable histology had abnormalities of 17p, resulting in TP53 gene deletion. These findings provide further support for the importance of gains of chromosomes 12, 8, and 6 and loss of 1p in the development of Wilms tumor. The results also support the association of unfavorable-histology Wilms tumors with TP53 deletion. The nonrandom losses of 16/16q, 7p, and 14q may point to the importance of genomic imbalance in the pathogenetic consequences and progression of Wilms tumor. 相似文献
47.
Lyme disease spirochete,Borrelia burgdorferi endemic at epicenter in Rondeau Provincial Park,Ontario
The Lyme disease spirochete, Borrelia burgdorferi Johnson, Schmidt, Hyde, Steigerwalt, and Brenner was discovered in blacklegged ticks, Ixodes scapularis Say at Rondeau Provincial Park, Ontario, Canada During this 2-yr study, spirochetes were found in B. burgdorferi-positive I. scapularis larvae attached to B. burgdorferi-infected white-footed mice, Peromyscus leucopus Rafinesque. Isolates of B. burgdorferi were cultured from blacklegged tick adults, and confirmed positive with polymerase chain reaction by targeting OspA and rrf (5S)-rrl (23S) genes. These findings show an endemic area for B. burgdorferi within an established population of L. scapularis at Rondeau Provincial Park. 相似文献
48.
Santos RL Wajid M Khan MN McArthur N Pham TL Bhatti A Lee K Irshad S Mir A Yan K Chahrour MH Ansar M Ahmad W Leal SM 《Human mutation》2005,26(4):396
Though many hearing impairment genes have been identified, only a few of these genes have been screened in population studies. For this study, 168 Pakistani families with autosomal recessive hearing impairment not due to mutations in the GJB2 (Cx26) gene underwent a genome scan. Two-point and multipoint parametric linkage analyses were carried out. Twelve families had two-point or multipoint LOD scores of 1.4 or greater within the transmembrane cochlear expressed gene 1 (TMC1) region and were subjected to further screening with direct DNA sequencing. Five novel putatively functional non-synonymous sequence variants, c.830A>G (p.Y277C), c.1114G>A (p.V372M), c.1334G>A (p.R445H), c.2004T>G (p.S668R), and c.2035G>A (p.E679K), were found to segregate within seven families, but were not observed in 234 Pakistani control chromosomes. The variants c.830A>G (p.Y277C), c.1114G>A (p.V372M), and c.1334G>A (p.R445H) occurred at highly conserved regions and were predicted to lie within hydrophobic transmembrane domains, while non-synonymous variants c.2004T>G (p.S668R) and c.2035G>A (p.E679K) occurred in extracellular regions that were not highly conserved. There is evidence that the c.2004T>G (p.S668R) variant may have occurred at a phosphorylation site. One family has the known splice site mutation c.536 -8T>A. The prevalence of non-syndromic hearing impairment due to TMC1 in this Pakistani population is 4.4% (95%CI: 1.9, 8.6%). The TMC1 protein might have an important function in K(+) channels of inner hair cells, which would be consistent with the hypothetical structure of protein domains in which sequence variants were identified. 相似文献
49.
50.
The relationship between depression and vitamin D deficiency is complex, with evidence mostly from studies affected by confounding and reverse causality. We examined the causality and direction of the relationship between 25-hydroxyvitamin D (25(OH)D) and depression in bi-directional Mendelian randomization (MR) analyses using information from up to 307,618 white British participants from the UK Biobank and summary results from the SUNLIGHT (n = 79,366) and Psychiatric Genomics consortia (PGC 113,154 cases and 218,523 controls). In observational analysis, the odds of depression decreased with higher 25(OH)D concentrations (adjusted odds ratio (OR) per 50% increase 0.95, 95%CI 0.94–0.96). In MR inverse variance weighted (IVW) using the UK Biobank, there was no association between genetically determined serum 25(OH)D and depression (OR per 50% higher 0.97, 95%CI 0.90–1.05) with consistent null association across all MR approaches and in data from PGC consortium. In contrast, genetic liability to depression was associated with lower 25(OH)D concentrations (MR IVW −3.26%, −4.94%–−1.55%), with the estimates remaining generally consistent after meta-analysing with the consortia. In conclusion, we found genetic evidence for a causal effect of depression on lower 25(OH)D concentrations, however we could not confirm a beneficial effect of nutritional vitamin D status on depression risk. 相似文献