全文获取类型
收费全文 | 18188篇 |
免费 | 1175篇 |
国内免费 | 46篇 |
学科分类
医药卫生 | 19409篇 |
出版年
2023年 | 153篇 |
2022年 | 228篇 |
2021年 | 425篇 |
2020年 | 276篇 |
2019年 | 430篇 |
2018年 | 600篇 |
2017年 | 507篇 |
2016年 | 471篇 |
2015年 | 598篇 |
2014年 | 666篇 |
2013年 | 900篇 |
2012年 | 1459篇 |
2011年 | 1465篇 |
2010年 | 721篇 |
2009年 | 605篇 |
2008年 | 1202篇 |
2007年 | 1136篇 |
2006年 | 1026篇 |
2005年 | 1108篇 |
2004年 | 1125篇 |
2003年 | 954篇 |
2002年 | 779篇 |
2001年 | 299篇 |
2000年 | 251篇 |
1999年 | 267篇 |
1998年 | 133篇 |
1997年 | 112篇 |
1996年 | 78篇 |
1995年 | 72篇 |
1994年 | 72篇 |
1993年 | 63篇 |
1992年 | 105篇 |
1991年 | 111篇 |
1990年 | 82篇 |
1989年 | 84篇 |
1988年 | 78篇 |
1987年 | 70篇 |
1986年 | 68篇 |
1985年 | 51篇 |
1984年 | 42篇 |
1983年 | 39篇 |
1982年 | 41篇 |
1981年 | 24篇 |
1980年 | 26篇 |
1979年 | 27篇 |
1978年 | 32篇 |
1974年 | 27篇 |
1973年 | 26篇 |
1969年 | 27篇 |
1967年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Postpartum fatigue is a normal condition that most women experience. Breastfeeding is often associated in women's minds as contributing to the feeling of overall perceived fatigue, and many women indicate that they have ceased breastfeeding because of fatigue. However, the relationship between feeding choice and perceived fatigue has never been established. Two hundred and fifty-three women participated in a study examining whether perceived fatigue differed for bottle-feeding and breastfeeding women at 3 different times during the postpartum period (2-4 days, 6 weeks, and 12 weeks postpartum). Results showed no significant differences for these 2 groups, suggesting that perceived fatigue during the postpartum period is not dependent on feeding choice. Additional analyses examining other variables with a potential effect were nonsignificant. Because perceived physical fatigue does not appear to be dependent on feeding choice, women should be prepared for the feeling of perceived fatigue during the postpartum period while at the same time be reassured that feeding choice is not correlated. 相似文献
3.
Marie-Paule Roth Hlne Coppin Patrick Descoins Jean-Bernard Ruidavets Anne Cambon-Thomsen Michel Clanet 《Journal of neuroimmunology》1991,34(2-3):215-222
The polymorphism at the HLA-DPB1 locus has been characterized in a large number of patients with multiple sclerosis (n = 112) and in healthy controls (n = 115). Both patients and controls lived in the southwest of France (in the Pyrénées Atlantiques) and had similar ethnic background. The typing procedure involved the selective amplification of the second exon of the DPB1 locus by polymerase chain reaction, followed by hybridization of the amplified DNA with 14 sequence-specific oligonucleotide probes. Individual alleles were identified by the pattern of hybridization of the different probes. The distribution of the DPB1 alleles was not significantly different in multiple sclerosis patients and controls (p = 0.11). This does not corroborate the reported association of multiple sclerosis with the primed lymphocyte typing (PLT)-defined DPw4 specificity and is not in favour of a role played by polymorphic residues of the DP molecule in susceptibility to multiple sclerosis. 相似文献
4.
Efficacy of intensive multitherapy for patients with type 2 diabetes mellitus: a randomized controlled trial 总被引:1,自引:1,他引:0 下载免费PDF全文
5.
6.
Selene Dall' Acqua Coutinho José Daniel Fedullo Sandra Helena Corrêa 《Medical mycology》2006,44(4):383-387
The objective of this study was to determine the presence of different species of the genus Malassezia in the healthy external auditory canal of wild felids maintained in captivity. One hundred and thirty-two adult animals (264 samples of cerumen), 77 males (58.3%) and 55 females (41.7%), were studied: large felids (55 animals) - 26 lions (Panthera leo), 13 tigers (Panthera tigris), 6 leopards (Panthera pardus), 6 jaguars (Panthera onca), 2 cheetahs (Acinonyx jubatus), 2 pumas (Puma concolor); small felids (77 animals) - 29 tiger cats (Leopardus tigrinus), 19 jaguarundis (Herpailurus yagouaroundi), 10 margays (Leopardus wiedii), 9 pampas cats (Oncifelis colocolo), 6 geoffroy's cats (Oncifelis geoffroyi), and 4 servals (Leptailurus serval). Samples were obtained by the introduction of a sterile swab into the ear canal after cleaning the auricle with an alcohol-ether solution. The swabs were seeded onto Petri dishes containing modified Mycosel agar and sterile olive oil was added to the surface of the medium before specimen seeding. The plates were incubated at 35oC for two weeks. The isolates were analyzed regarding macro-and micromorphology and identified through catalase tests and growth on Tween 20, 40, 60 and 80. Malassezia spp. were isolated from 58 of the felids studied (43.9%) and from 102 samples of cerumen (38.6%). Malassezia sympodialis was isolated exclusively in large felids (33 animals-56.9%), and Malassezia pachydermatis exclusively in smaller varieties (25 animals - 43.1%). The incidence of fungi was higher in lions, with yeast being isolated in 25 of 26 animals (96.2%). Forty-eight strains (47.1%) were isolated from the right ear canal and 54 (52.9%) from the left. Although M. pachydermatis is the species considered a member of the microbiota of the mammalian external ear canal these results suggest that M. sympodialis participates in the microbiota of large felids. 相似文献
7.
ImmunoCyt/uCyt is a fluorescent test combining three monoclonal antibodies. In this study, it has been tested as a complement to cytology in the detection of urothelial carcinoma in urine. It has been performed simultaneously with standard cytology and cystoscopy on 870 urine analyses from one hospital. In 136 cases, one or more bladder tumors were found. Overall sensitivity of cytology, ImmunoCyt/uCyt and combined analyses reached 29, 74 and 84%, respectively, and overall specificity was 98, 62 and 61%. The negative predictive value of cytology, ImmunoCyt/uCyt and both analyses was 88, 93 and 95%, respectively, and the positive predictive value was 70, 26 and 29%. The sensitivity of cytology for low malignant potential neoplasms, low- and high-grade papillary carcinomas was 6, 18 and 53%, while it reached 71, 79 and 93% when combined with ImmunoCyt/uCyt. The sensitivity of cytology for stages Ta, T1, T2 and over and Tis tumors was 12, 67, 47 and 50%, while it reached 78, 83, 79 and 100% when combined with ImmunoCyt/uCyt. In the absence of tumor on cystoscopy but with positive ImmunoCyt/uCyt, 18% of patients developed a tumor, 2-6 months later. Of the 109 cases diagnosed as suspicious for malignancy by cytology, a tumor was present in 30 cases and ImmunoCyt/uCyt was positive in 22 (73%) of them. In conclusion, ImmunoCyt/uCyt may be used to postpone cystoscopies in patients followed for bladder cancer and may help to save cytologist and pathologist screening time. 相似文献
8.
9.
10.
Rosangela Saga Kamikawa Marlene Fenyo Pereira Angela Fernandes Maria Inês Meurer 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2006,101(3):374-378
OBJECTIVE: To determine the location in soft tissues of the calcifications, similar to calcified carotid atheromas, that can be observed radiographically in the cervical region in panoramic radiographs. STUDY DESIGN: In each anatomic cadaver specimen preserved in formol, consisting of the head and neck, radiopaque spheres (made from gutta-percha) were positioned in anatomic structures of the cervical region that can be sites of calcification. For each anatomic structure marked in this way, panoramic radiography was performed, consisting of 17 radiographs. The images obtained were analyzed by 24 examiners who indicated which radiographs, in their opinion, presented the radiopaque reference projected in the region of bifurcation of the carotid artery. Analysis of 2 proportions from agreement and disagreement was used to determine radiopacities that could be confused in panoramic radiographs with calcified atheromas in the carotid artery. RESULTS: The results showed that 75% (18) of the examiners correctly indicated the reference in the bifurcation of the carotid artery and 79.2% (19) indicated a triticeous cartilage as calcified atheroma of the carotid artery. CONCLUSIONS: Calcified atheromas of the carotid artery are not the only features that can produce radiopaque images lateral to the panoramic radiograph; the presence of calcification in the triticeous cartilage also can induce an erroneous diagnosis of calcified carotid atheroma. 相似文献