全文获取类型
收费全文 | 19295篇 |
免费 | 1433篇 |
国内免费 | 60篇 |
专业分类
耳鼻咽喉 | 296篇 |
儿科学 | 1103篇 |
妇产科学 | 581篇 |
基础医学 | 2208篇 |
口腔科学 | 414篇 |
临床医学 | 2085篇 |
内科学 | 3781篇 |
皮肤病学 | 507篇 |
神经病学 | 1422篇 |
特种医学 | 501篇 |
外科学 | 2573篇 |
综合类 | 1030篇 |
一般理论 | 15篇 |
预防医学 | 1860篇 |
眼科学 | 503篇 |
药学 | 1127篇 |
1篇 | |
中国医学 | 16篇 |
肿瘤学 | 765篇 |
出版年
2021年 | 229篇 |
2020年 | 141篇 |
2019年 | 188篇 |
2018年 | 295篇 |
2017年 | 213篇 |
2016年 | 206篇 |
2015年 | 221篇 |
2014年 | 313篇 |
2013年 | 546篇 |
2012年 | 608篇 |
2011年 | 624篇 |
2010年 | 434篇 |
2009年 | 419篇 |
2008年 | 538篇 |
2007年 | 602篇 |
2006年 | 641篇 |
2005年 | 582篇 |
2004年 | 484篇 |
2003年 | 458篇 |
2002年 | 463篇 |
2001年 | 457篇 |
2000年 | 427篇 |
1999年 | 433篇 |
1998年 | 288篇 |
1997年 | 298篇 |
1996年 | 346篇 |
1995年 | 286篇 |
1994年 | 250篇 |
1993年 | 273篇 |
1992年 | 366篇 |
1991年 | 365篇 |
1990年 | 375篇 |
1989年 | 336篇 |
1988年 | 292篇 |
1987年 | 326篇 |
1986年 | 260篇 |
1985年 | 205篇 |
1984年 | 209篇 |
1983年 | 179篇 |
1982年 | 145篇 |
1979年 | 139篇 |
1978年 | 125篇 |
1959年 | 345篇 |
1958年 | 762篇 |
1957年 | 877篇 |
1956年 | 773篇 |
1955年 | 804篇 |
1954年 | 781篇 |
1949年 | 182篇 |
1948年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Since the experimental infection by hydatid cysts ( Echinococcus granulosus ) in mice causes immunomodulation of the host, the effects of hydatid fluid (HF) and fractions of HF were compared in vitro and in vivo . Fractions of HF were obtained using ammonium sulphate precipitation, chloroform/methanol extraction and thin-layer chromatography (TLC). HF proved to be toxic to murine peritoneal macrophages in vitro , and when macrophages were incubated with the different fractions of HF, most toxicity was found in a single TLC-purified fraction with an adjuvant-like effect on the production of specific antibodies against bovine albumin and human red blood cells in mice. Treatment of mice with the toxin caused a drop in the percentage of peripheral blood lymphocytes. Flow-cytometric analysis showed that T-cells from toxin-treated mice had lower membrane-CD3, CD4 and CD8 density, and had higher percentages of CD8+ splenocytes and CD4+ thymocytes expressing CD25. The toxin caused a down-regulation of CD4 and CD8 expression on thymocytes in vitro , that was dependent on the presence of macrophages. The results may attribute to these toxins a role in the host-parasite relationship of hydatidosis. 相似文献
53.
R Sullivan 《Journal of the Royal Society of Medicine》1996,89(8):467-473
That a well-developed and hierarchical medical profession existed in Pharaonic Egypt is without doubt. What is a matter of contention is the existence of a recognizable surgical profession, or even of the practice of surgery by medically qualified personnel. Palaeorchaeological specimens that demonstrate some form of surgical procedure are rare. Medical papyri and the treatises of the historians of antiquity provide a far more reliable source of information on surgical practice. They have indicated possible titles for surgeons, and the types of instruments used. 相似文献
54.
R. DE BOER W. A. D. VAN DER HOEVEN S. O. STAPEL 《Clinical and experimental allergy》1995,25(8):765-770
Background: Fluctuations in the level of mite allergens in domestic house dust are the result of changes in the balance between synthesis, removal and decay. Purely physical forces as well as enzymatic degradation, mediated by house dust inhabiting microbes, may contribute to the decay of allergens in domestic dust. Knowledge about the speed of decay is essential for an understanding of the dynamics of allergen levels. Objective: The present study is a quantitative assessment of the speed of decay at nine combinations of temperature (15°C, 20°C and 25°C) and relative humidity (33%, 55% and 75%). Methods: Samples of mite infested material of an old rug were stored at these temperature/relative humidity-combinations for 6, 12 or 18 months, after the mites were killed by cither a freezing treatment or an acaricide (lindane). The microbes living in the rug presumably survive these treatments. Concentrations of Der p I and Der p II + Der f II. in extracts of the rug material, were measured by a radio immunoassay. Results: No significant changes in the levels of Der p I and Der p II +Der f II, could be detected even after 11/2 year at a high temperature and humidity. Conclusion: These findings incidate that mite allergens can be extremely stable under normal domestic circumstances. 相似文献
55.
Melanie Inkster Alan Montgomery Peter Donnan Tom MacDonald Frank Sullivan Tom Fahey 《The British journal of general practice》2005,55(521):931-937
BACKGROUND: Studies show that 60-75% of treated patients with hypertension in general practice, still do not reach the recommended blood pressure targets of <150/90 mmHg. AIM: To investigate aspects of hypertension management in relation to sociodemographic variables, antihypertensive drug treatment, and organisational factors in primary care. DESIGN OF STUDY: Observational study over 3 years. SETTING: Eight general practices in Tayside, UK. METHOD: Participants were 560 randomly selected patients aged 40-79 years receiving treatment for hypertension. The outcome measurement was blood pressure control, expressed in binary form based on the British Hypertension Society audit standard of <150/90 mmHg. RESULTS: Of 536 eligible patients, 261 (49%) were defined as having inadequate blood pressure control at the end of the study period. No significant associations were discovered with sex, age, deprivation score and comorbidity. In those patients with inadequate control, 30% had no modifications to their drug treatment during the study period. Blood pressure control at the end of the study period was not associated with number of antihypertensive drugs taken or number of antihypertensive drug modifications. The mean number of clinician contacts was 11 (standard deviation = 8), and mean continuity in primary care was high, although this was not associated with improved blood pressure control. A higher proportion of hypertension-related consultations were associated with increased odds of having inadequate blood pressure control. CONCLUSION: Achieving adequate blood pressure control continues to represent a substantial health problem in a significant proportion of the hypertensive population. Patient, physician and organisational elements play a role in ensuring effective delivery of hypertension care in the community. 相似文献
56.
57.
M J Buxton S D Sullivan L F Andersson C J Lamm B Liljas W W Busse S Pedersen K B Weiss 《The European respiratory journal》2004,24(4):568-574
Early intervention with budesonide is an effective strategy for mild persistent asthma, which has been shown to provide additional clinical benefits at a low incremental cost using USA cost data. The present authors analysed whether this strategy would be cost-effective using cost data for other countries. Based on the 3-yr prospective, randomised, double-blind inhaled Steroid Treatment As Regular Therapy (START) in early asthma study (comparing budesonide and placebo combined with usual asthma therapy), the cost-effectiveness was estimated separately for eight different countries, from both healthcare payer and societal perspectives, of adding budesonide to usual asthma therapy. Local unit costs were applied to data for the total trial population. Incremental cost-effectiveness ratios (ICER) were estimated as cost per symptom-free day (SFD) gained. Budesonide increased SFDs by an average of 14.1 days annually. From a healthcare payer perspective, budesonide would reduce the total cost of asthma care in Australia. In Sweden, Canada, France, Spain, UK, China and the USA, the ICER ranged from US$2.4-11.3 per SFD. From a societal perspective, budesonide would be cost-saving in Australia, Canada and Sweden. In conclusion, for countries where costs with budesonide are higher, the policy implication has to be determined by that health system's willingness to pay for an additional symptom-free day. However, where budesonide therapy increases symptom-free days and reduces total costs, the policy conclusion clearly favours early intervention. 相似文献
58.
59.
Antiserum raised to a factor elaborated by a lymphoblastoid cell line derived from the peripheral blood cells of an HLA-B27 positive patient with ankylosing spondylitis specifically lyses the B27 positive, but not the B27 negative, cells of ankylosing spondylitis patients. The cells of B27 positive and B27 negative normal controls are not lysed. This serum has similar specificity to antisera against cross-reactive bacteria. 相似文献
60.