全文获取类型
收费全文 | 12252篇 |
免费 | 705篇 |
国内免费 | 39篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 276篇 |
妇产科学 | 247篇 |
基础医学 | 1668篇 |
口腔科学 | 1646篇 |
临床医学 | 855篇 |
内科学 | 2599篇 |
皮肤病学 | 304篇 |
神经病学 | 1010篇 |
特种医学 | 290篇 |
外科学 | 1269篇 |
综合类 | 64篇 |
预防医学 | 1295篇 |
眼科学 | 157篇 |
药学 | 769篇 |
中国医学 | 111篇 |
肿瘤学 | 323篇 |
出版年
2023年 | 126篇 |
2022年 | 300篇 |
2021年 | 455篇 |
2020年 | 317篇 |
2019年 | 454篇 |
2018年 | 525篇 |
2017年 | 345篇 |
2016年 | 375篇 |
2015年 | 431篇 |
2014年 | 547篇 |
2013年 | 662篇 |
2012年 | 1025篇 |
2011年 | 1106篇 |
2010年 | 544篇 |
2009年 | 450篇 |
2008年 | 728篇 |
2007年 | 754篇 |
2006年 | 599篇 |
2005年 | 509篇 |
2004年 | 359篇 |
2003年 | 314篇 |
2002年 | 310篇 |
2001年 | 225篇 |
2000年 | 207篇 |
1999年 | 166篇 |
1998年 | 45篇 |
1997年 | 35篇 |
1996年 | 25篇 |
1995年 | 25篇 |
1994年 | 37篇 |
1993年 | 25篇 |
1992年 | 75篇 |
1991年 | 77篇 |
1990年 | 52篇 |
1989年 | 69篇 |
1988年 | 62篇 |
1987年 | 59篇 |
1986年 | 58篇 |
1985年 | 56篇 |
1984年 | 47篇 |
1983年 | 32篇 |
1982年 | 28篇 |
1979年 | 32篇 |
1977年 | 26篇 |
1976年 | 23篇 |
1975年 | 25篇 |
1971年 | 21篇 |
1970年 | 33篇 |
1969年 | 26篇 |
1968年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Three small peptides with a typical cysteine-rich domain (TFF or P-domain) display a specific folding structure (trefoil); they are abundantly expressed on mucosal surfaces of normal and neoplastic gastrointestinal tissues. This epithelial location coincides with mucin secretion and, although not proven beyond doubt, this association is suggestive of their function in maintenance of surface integrity. Using normal colon epithelium, premalignant lesions and tumor samples and specific antibodies we studied expression of these peptides in colorectal carcinomas. RT PCR was performed to extend the sensitivity of the assays. While coexpression of pS2, hITF, MUC1 and MUC2 was demonstrated, MUC5 was absent and no simultaneous activity of pS2 and SML1 (as in gastric mucosa and carcinoma) was noted in rectal tumors. Actively transcribed and expressed cytokeratin 20 and GAPDH were used as experimental controls for immunostaining and RT-PCR, respectively. 相似文献
52.
Machado CS 《Jornal de pediatria》1995,71(5):241-247
A review of the current knowledge of mucosal immune response development indicates that migration of immunocytes to mucosal surfaces is an early event during fetal life. The morphologic development of gut-associated lymphoid tissues (lymphoid follicles, Peyer's patches and tonsils) occurs from 11-20 weeks' gestation upwards. But they are active only after birth, when usually antigenic challenge takes place. The complete development of secretory immunity is a postnatal achievement. In infancy, some environmental factors such as feeding and oral antigenic challenge seems to modulate immune response development. Breastfeeding, by means of antiinfectious, antiinflammatory and immunomodulating properties, besides completing infant secretory immunity, also stimulates immunological maturation on mucosal surfaces. 相似文献
53.
54.
Machado MH 《Revista brasileira de enfermagem》1999,52(4):589-595
The present article presents the sociological analysis of the nursing profession, focussing the specificities of the profession on the basis of the component elements of a profession, according to the theoretical system of the sociology of professions. At the end of the 20th century and the beginning of the new millennium, nursing faces crucial questions for the profession, which bring back the need to restructure the strategic considerations that make up the political agenda of the nursing profession. Specific knowledge, professional qualification, particularities of the work process, monopoly of the professional exercise, and the configuration of the hierarchy of the nursing team are some of the items dealt within this article. As one of the essential professions in the health area, nursing needs to reach the next century with a new perspective, knowing how and in which conditions it will develop in a context of paradigmatic changes. Considering this new context, a political agenda for nursing professionals will have to contemplate the several aspects that make up a profession, that is, specific knowledge, exclusive labor market, form of organization, among others. 相似文献
55.
56.
57.
Nakamura-Palacios EM de Oliveira RW Gomes CF 《Progress in neuro-psychopharmacology & biological psychiatry》1999,23(8):1369-1388
1. Effects of diazepam (DZP) or haloperidol (HAL) on convulsions and behavioral responses (locomotion, circling, spying and head shaking) induced by bilateral electrical stimulation in the medial prefrontal cortex (mPFC) were examined. 2. Male Wistar rats were electrically stimulated (ten 30-sec trains, 60 Hz, 80-100 microA) bilaterally in the mPFC and their behavior was simultaneously observed in an open field in daily session. 3. DZP and HAL dose-response curves (0, 0.5, 1.25, 2.5 and 5 mg/kg, i.p., 30 min before electrical stimulation session) were determined after a baseline of behavioral responses was established. 4. DZP dose-dependently decreased head shaking and convulsions, had no effect in circling and spying behaviors, and increased locomotion except at the highest dose. HAL reduced locomotion, circling and spying behaviors in a dose-dependent manner, but did not affect convulsions or head shaking. 5. These results demonstrated that convulsion and behavioral responses induced by electrical activation of the mPFC were modified by DZP or HAL. Therefore, the mPFC is involved in the mediation of neural and/or behavioral activity that may be implicated in some central effects of psychoactive drugs. 相似文献
58.
The current study investigated whether an ipsilesional bias in line bisection, a conventional measure for diagnosing hemispatial neglect, persists even in the absence of this syndrome in patients with chronic lesions restricted to posterior association cortex or dorsolateral prefrontal cortex. Both left and right hemisphere parietal lesions produced ipsilesional bisection errors, and to a comparable degree. Patients with lesions in frontal cortex, on the other hand, did not show a consistent bias. We conclude that chronic parietal lesions produce an ipsilesional bias in line bisection, even in the absence of other clinical signs of neglect, and that left hemisphere lesions can affect line bisection to the same degree as right hemisphere lesions. 相似文献
59.
Gomes J Lloyd OL Revitt DM 《International archives of occupational and environmental health》1999,72(1):40-45
Farm workers in developing countries tend not to use protective measures while handling pesticides. This study investigates
the use of personal protection equipment and the practice of safety and hygiene procedures in the handling of pesticides in
agriculture. Methods: Through a multi-stage sampling technique, one-fifth of the farms in a region were selected and all the farm workers at these
farms were included in the study. A comparison population matching in age, socio-economic status and stay in the region was
selected. A specifically designed questionnaire was used to collect information on the use of protective measures and the
practice of safety and hygiene during work and on the disposal of empty pesticide containers. Blood pressure and erythrocyte
acetylcholinesterase (AChE) activity were measured in the exposed and the unexposed populations. Results: Protective equipment was worn by a minority of farm workers – gloves, by 35%; work coveralls, by 36%; a scarf to cover the
nose and mouth, by 39%; and shoes at work, by 79%. With regard to personal hygiene measures, 83% of the workers changed clothes
after work and the same proportion took a shower after work; 63% and 46% drank and ate while at work respectively; and 11%
used articles of domestic use in the preparation of pesticides on the farm. Most of the farm workers (96%) were asked to prepare
pesticides for spraying by the foreman and 61% were asked to spray the pesticides on the crops. AChE activity was highly significantly
depleted in the exposed population as compared with the unexposed population. Conclusions: AChE depletion was found to be negatively associated with the use of gloves, of work coveralls, and of a scarf to cover the
nose and mouth and with the implementation of safety and hygiene procedures on the farm. AChE depletion was positively associated
with the frequency of pesticide spraying.
Received: 30 January 1998 / Accepted: 19 August 1998 相似文献
60.
Techniques of time series analysis were used to examine historical records of the incidence of diphtheria, pertussis, and measles, and of deaths by measles in Portugal during the twentieth century. There are statistically significant seasonal and long-term oscillations in the incidence of these diseases. Seasonal oscillations appear to be in close association with the resumption of school classes in the fall in the case of diphtheria, but not in pertussis and measles. Long-term oscillations in pertussis (3.5–4 year period) and measles (3-year period), before vaccination, corroborate theoretical predictions about the dynamics of these diseases, whereas absence of long-term oscillations in diphtheria is probably due to the influential presence of carriers upon the dynamics of the disease. Mass vaccination strongly suppressed disease incidence, did not eliminate seasonal oscillations, and appeared to have acted to lengthen long-term periodicity in pertussis and measles. 相似文献