全文获取类型
收费全文 | 13535篇 |
免费 | 831篇 |
国内免费 | 61篇 |
专业分类
耳鼻咽喉 | 116篇 |
儿科学 | 657篇 |
妇产科学 | 294篇 |
基础医学 | 1828篇 |
口腔科学 | 202篇 |
临床医学 | 1138篇 |
内科学 | 2858篇 |
皮肤病学 | 291篇 |
神经病学 | 1373篇 |
特种医学 | 589篇 |
外国民族医学 | 4篇 |
外科学 | 2118篇 |
综合类 | 173篇 |
一般理论 | 3篇 |
预防医学 | 857篇 |
眼科学 | 170篇 |
药学 | 712篇 |
1篇 | |
中国医学 | 21篇 |
肿瘤学 | 1022篇 |
出版年
2022年 | 86篇 |
2021年 | 190篇 |
2020年 | 108篇 |
2019年 | 158篇 |
2018年 | 215篇 |
2017年 | 175篇 |
2016年 | 180篇 |
2015年 | 217篇 |
2014年 | 284篇 |
2013年 | 363篇 |
2012年 | 574篇 |
2011年 | 634篇 |
2010年 | 394篇 |
2009年 | 396篇 |
2008年 | 540篇 |
2007年 | 564篇 |
2006年 | 559篇 |
2005年 | 644篇 |
2004年 | 500篇 |
2003年 | 485篇 |
2002年 | 499篇 |
2001年 | 444篇 |
2000年 | 484篇 |
1999年 | 391篇 |
1998年 | 238篇 |
1997年 | 222篇 |
1996年 | 199篇 |
1995年 | 164篇 |
1994年 | 157篇 |
1993年 | 147篇 |
1992年 | 299篇 |
1991年 | 270篇 |
1990年 | 262篇 |
1989年 | 304篇 |
1988年 | 267篇 |
1987年 | 271篇 |
1986年 | 225篇 |
1985年 | 240篇 |
1984年 | 198篇 |
1983年 | 167篇 |
1982年 | 111篇 |
1981年 | 108篇 |
1980年 | 73篇 |
1979年 | 152篇 |
1978年 | 111篇 |
1977年 | 75篇 |
1976年 | 82篇 |
1975年 | 74篇 |
1974年 | 105篇 |
1973年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Intestinal schistosomiasis japonica: CT-pathologic correlation 总被引:1,自引:0,他引:1
Lee RC; Chiang JH; Chou YH; Rubesin SE; Wu HP; Jeng WC; Hsu CC; Tiu CM; Chang T 《Radiology》1994,193(2):539
82.
Structural modification of receptor-binding technetium-99m complexes in order to improve brain uptake 总被引:2,自引:0,他引:2
Bernd Johannsen Ralf Berger Peter Brust Hans-Juergen Pietzsch Matthias Scheunemann Sepp Seifert Hartmut Spies Rosemarie Syhre 《European journal of nuclear medicine and molecular imaging》1997,24(3):316-319
Low brain uptake is a generally accepted problem in developing technetium-99m brain receptor imaging agents. For a class of potential 5-HT2A receptorbinding agents we tried to improve the original low brain uptake of 0.4% injected dose (ID) in rats 5 min p.i. by modifying the lipophilic properties of the molecules. Because of the presence of a protonable nitrogen, which according to the pK
a value leads to ionization of the molecule at blood pH, the pK
a value was considered to be the parameter most suitable for adjustment of lipophilicity. Insertion of ether-oxygen in the molecule of five candidates lowers the apparent pK
a value from 10.0 to 8.3 and dramatically increases the brain uptake to 1.3% ID at 5 min. The direct relationship between brain uptake and apparent pK
a cannot be simply explained by the increase in the pK
a-governed proportion of the neutral species. 相似文献
83.
Plantar defects are a challenge for the plastic surgeon; from 1984–1995 59 operations were performed in 57 patients. The radial forearm flap and the latissimus dorsi (LD) flaps were mainly used depending on the amount of tissue loss. Local flaps such as dorsalis pedis and instep flaps were used for smaller defects. The radial forearm flap is ideal in terms of thickness and stability for the sole but limited in its size. The LD flap is a safe procedure especially for severe injuries and osteitis, but has the disadvantage of being bulky and debulking procedures are frequently performed. For nerve reconstruction deep sensibility seems to be sufficient in order to obtain stable postoperative results. In this report the different operative methods are evaluated. Since 1991, the patients were monitored with static and dynamic foot pressure measurements and gait analysis to assess the postoperative result and prevent pressure ulcers, scar irritation and hyperkeratosis. Preoperative investigations may contribute to an optimal schedule for planning and stabilization of the operative regimen. 相似文献
84.
85.
Dr. David H. Berger MD Barry W. Feig MD Donald Podoloff MD James Norman MD C. Wayne Cruse MD Douglas S. Reintgen MD Merrick I. Ross MD 《Annals of surgical oncology》1997,4(3):247-251
Background: If cutaneous lymphoscintigraphy (CL) is accurate in predicting the draining lymph node basins at risk from primary axial
melanomas, then regional metastases should only occur in those lymph node basins identified by CL.
Methods: This study is a retrospective review of patients undergoing CL for primary axial melanomas from June 1, 1985, until June
31, 1992. Data retrieved included age, gender, number of basins identified, location of basins identified, management of basins,
recurrence in lymphatics, development of distant disease, and long-term follow-up.
Results: A total of 181 patients underwent elective LND, and 48 patients (27%) had melanoma in the nodes within the dissected basin.
Of these 181 patients, seven developed nodal metastases as their site of first recurrence. All seven recurrences were seen
at sites dissected or at sites indicated by CL, which the primary surgeon elected not to treat initially. Of the 116 patients
observed, 16 (14%) developed lymph node metastases as their first site of recurrence. Fifteen of these 16 patients had their
site of lymph node metastases predicted by CL. In this study, CL predicted 98.6% of all lymph node metastases.
Conclusions: The high overall reliability of CL as demonstrated by long-term follow-up indicates that the information obtained by CL can
be reliably used to guide intervention. Initial evaluation of patients with high-risk cutaneous melanomas at sites with ambiguous
lymphatic drainage must include CL in order to determine the draining lymph node basins and to plan therapy.
Presented at the 47th Annual Cancer Symposium of The Society of Surgical Oncology, Houston, Texas, March 17–20, 1994. 相似文献
86.
In December, 1989, the Department of Transportation (DOT) in conjunction with the Federal Aviation Administration (FAA) mandated an extensive urine drug testing program for selected positions within the airline industry. At the end of 1 year we have tested 7,872 applicants under these rules, with a positive finding rate of 0.17%. We have also tested 32,157 applicants, including those applying for DOT-covered positions, with a positive rate of 2.82%. Considering only the two major drugs of abuse--marijuana and cocaine--we found the positive rate to be an order of magnitude greater than the rate discovered under the DOT program. We present these data together with a discussion of some of the possible reasons for this major disparity. We also present findings for barbiturates and benzodiazepines which are not tested under the DOT program, but which have safety implications related to the aviation industry. 相似文献
87.
Joseph Berger 《Canadian Medical Association journal》1988,138(4):303-304
88.
We have developed a reliable technique for labeling and examining neural structures in soft tissues associated with articular joints and have tested it in human wrist joints under various specimen-related conditions. The labeling protocol employs an immunohistochemical process with a panneuronal marker (PGP 9.5) as the primary antibody and Alexa Fluor 488 as the fluorescing secondary antibody. Imaging was done using a confocal laser scanning microscope, which produced exceptionally detailed three-dimensional images of nerve endings and transiting nerve fibers from thick sections of wrist joint ligaments obtained from human cadavers. The protocol provided a practical postmortem window for specimen acquisition and processing without significant apparent worsening of image quality. The images produced are resistant to fading with repeated exposure to a fluorescent light source, which gives many opportunities for observation. Background staining is minimal, producing high contrast labeling of target tissues, which, in turn, enhances image analysis. 相似文献
89.
Lesley Barclay RN CM BA MEd Louise Everitt RN CM Post Grad Dip-Comm Health Frances Rogan RN CM B App S M Com Nurs Virginia Schmied RN CM BA MA Hons Aileen Wyllie RN CM BA MHPEd 《Journal of advanced nursing》1997,25(4):719-728
This paper presents the results of a qualitative study conducted by midwife researchers into women's experience of new motherhood. Data were collected using focus groups involving 55 first-time mothers and analysed using grounded theory method. The analysis produced six categories: 'realizing', 'unready', 'drained', 'aloneness', 'loss' and 'working it out'. The core category, 'becoming a mother', integrates all other categories and encapsulates the process of change experienced by women. Also explained are factors mediating the often distressing experience of becoming a mother. The analysis provides a conceptualization of early motherhood enabling the development of strategies for midwives, nurses and others helping women negotiate this challenge. 相似文献
90.
Assessment of immunization as a technique to extend the chilled storage life of vacuum‐packaged lamb
The growth at — 1.5°C of Lactobacillus delbrueckii, a meat spoilage organism, was evaluated on vacuum‐packaged lamb legs obtained from animals immunized against that organism. Growth was significantly lower than that on similarly treated legs obtained from non‐immunized lambs. These findings suggest that immunization against spoilage organisms may contribute toward increasing the chilled storage life of fresh meat. 相似文献