全文获取类型
收费全文 | 216431篇 |
免费 | 15988篇 |
国内免费 | 770篇 |
专业分类
耳鼻咽喉 | 2309篇 |
儿科学 | 5722篇 |
妇产科学 | 4512篇 |
基础医学 | 28019篇 |
口腔科学 | 4833篇 |
临床医学 | 20598篇 |
内科学 | 46122篇 |
皮肤病学 | 2839篇 |
神经病学 | 20568篇 |
特种医学 | 7156篇 |
外国民族医学 | 13篇 |
外科学 | 33937篇 |
综合类 | 3663篇 |
现状与发展 | 2篇 |
一般理论 | 296篇 |
预防医学 | 19835篇 |
眼科学 | 4459篇 |
药学 | 14813篇 |
1篇 | |
中国医学 | 374篇 |
肿瘤学 | 13118篇 |
出版年
2023年 | 857篇 |
2022年 | 1430篇 |
2021年 | 3506篇 |
2020年 | 2155篇 |
2019年 | 3461篇 |
2018年 | 4053篇 |
2017年 | 3293篇 |
2016年 | 3475篇 |
2015年 | 4156篇 |
2014年 | 6205篇 |
2013年 | 9005篇 |
2012年 | 13359篇 |
2011年 | 14576篇 |
2010年 | 8237篇 |
2009年 | 7436篇 |
2008年 | 13853篇 |
2007年 | 14688篇 |
2006年 | 14159篇 |
2005年 | 14633篇 |
2004年 | 14024篇 |
2003年 | 13108篇 |
2002年 | 12698篇 |
2001年 | 2112篇 |
2000年 | 1698篇 |
1999年 | 2287篇 |
1998年 | 2907篇 |
1997年 | 2498篇 |
1996年 | 2259篇 |
1995年 | 2021篇 |
1994年 | 1827篇 |
1993年 | 1714篇 |
1992年 | 1327篇 |
1991年 | 1301篇 |
1990年 | 1206篇 |
1989年 | 1105篇 |
1988年 | 1142篇 |
1987年 | 1143篇 |
1986年 | 1124篇 |
1985年 | 1211篇 |
1984年 | 1573篇 |
1983年 | 1550篇 |
1982年 | 1875篇 |
1981年 | 1695篇 |
1980年 | 1610篇 |
1979年 | 917篇 |
1978年 | 1035篇 |
1977年 | 999篇 |
1976年 | 882篇 |
1975年 | 730篇 |
1974年 | 724篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Women''s Health: Hormone replacement therapy for the primary prevention of chronic diseases: recommendation statement from the Canadian Task Force on Preventive Health Care 下载免费PDF全文
992.
Clinical trial registration: a statement from the International Committee of Medical Journal Editors 下载免费PDF全文
993.
Quantitative magnetization transfer imaging (qMTI) methods are able to estimate fundamental sample parameters, such as the relative size of the solid-like macromolecular proton pool and the spin exchange rate between this pool and the directly measured free water protons. One such method is selective inversion recovery (SIR), in which the free water protons are selectively inverted and the signal is fit to a biexponential function of the inversion time (TI). SIR uses only low-power pulses and requires no separate RF (B1) or static field (B0) field maps, and the analysis is largely independent of the macromolecular pool lineshape. These are all advantages over steady-state off-resonance saturation qMTI methods. However, up to now, SIR has been implemented only with repetition times TR>T1. This paper describes a modification of SIR with smaller TR values and a greater signal-to-noise ratio (SNR) efficiency. 相似文献
994.
995.
Sarah L. Turner Trudy L. Horton Pamela Ritchie John D. Horton 《Developmental and comparative immunology》1991,15(4):319-328
A miniaturized, “hanging-drop” bioassay reveals that splenocytes from earlythymectomized (Tx) Xenopus can respond (by enhanced thymidine incorporation) to thymicdependent “cytokines” generated in PHA- or alloantigen-stimulated cultures. Preliminary evidence, using fluorescence activated cell sorting, indicates that surface IgM− splenocytes, rather than sIgM+ cells, from Tx toads are sensitive to the crude, splenocyte-derived, active supernatants. Although these responsive cells display residual, but low, reactivity to PHA, their thymus independence is suggested by flow cytometric observations using the anti-T cell monoclonal antibody XT-1. The development of “T-like” cells in Tx Xenopus is discussed. 相似文献
996.
Salim H. Khalil Mohammed H. Qari John M. Jackson Robert Haywood Pyle Hassan El-Solh Abdallah Al-Nasser 《Leukemia research》1994,18(12):881-883
Geographical variations in the incidence of disease are of considerable theoretical and practical importance. It has been claimed that the distribution of acute lymphoblastic leukemia (ALL) phenotypes in Saudi Arabia is different from that recorded in the Western literature. One hundred and twelve (112) patients under 15 years of age, diagnosed as ALL between January 1992 and May 1994 had immunophenotypes performed on their blast cells. Common ALL (cALL) together with pre-B-ALL, formed 86.5% of the total; B-cell 3%, T-cell 6% and null cell 4.5%. These figures are not significantly different from the Western literature. A previous claim from this institution in 1990, that both null and B-cell ALL were significantly increased compared with elsewhere, is not supported by the present figures. Age and sex distribution, and FAB classification, L1 77%, L2 20% and L3 3%, were also of the same order as described elsewhere and, in particular, there was no increase in the frequency of L3 subtype. 相似文献
997.
Osteoarticular complications may occur with a variety of invasive fungal infections, and seem to be increasing with growing
use of prosthetic joints and as the immunosuppressed patient population increases. Epidemiology, pathogenesis, presentation,
and management strategies differ somewhat among the different fungal species. This review focuses on recent developments in
diagnostic and management approaches for patients with osteoarticular mycoses, and outlines specific treatment strategies
for the different species. 相似文献
998.
999.
Sinonasal surfactant protein A1, A2, and D gene expression in cystic fibrosis: a preliminary report. 总被引:1,自引:0,他引:1
Bradford A Woodworth Rachel Wood John E Baatz Rodney J Schlosser 《Otolaryngology--head and neck surgery》2007,137(1):34-38
OBJECTIVE: To measure alterations in SPA1, A2, and D gene expression in various forms of inflammatory chronic rhinosinusitis (CRS). STUDY DESIGN AND SETTING: Sinus mucosal biopsies were performed in patients with allergic fungal rhinosinusitis (AFS), CRS with nasal polyposis, cystic fibrosis (CF), and controls. SP mRNA was measured with quantitative polymerase chain reaction. RESULTS: Patients with CF (n = 4) showed significantly increased SPA1 (82-fold), SPA2 (100-fold), and SPD (47-fold) mRNA (P < 0.05) when compared with controls (n = 5). Patients with CRS with nasal polyposis (n = 5) also demonstrated elevated SPA1 (27-fold), SPA2 (13-fold), and SPD (13-fold). Patients with AFS (n = 7) had increased SPA1 (5-fold), SPA2 (9-fold), and SPD (17-fold), but were not statistically significant. CONCLUSION: SPA1, A2, and D are upregulated in various forms of CRS, but are significantly elevated in cystic fibrosis CRS. SIGNIFICANCE: Understanding the role of SPs in CRS will help develop novel treatment approaches for sinonasal pathoses. 相似文献
1000.