全文获取类型
收费全文 | 20434篇 |
免费 | 1641篇 |
国内免费 | 611篇 |
专业分类
耳鼻咽喉 | 183篇 |
儿科学 | 316篇 |
妇产科学 | 571篇 |
基础医学 | 2580篇 |
口腔科学 | 419篇 |
临床医学 | 2286篇 |
内科学 | 4137篇 |
皮肤病学 | 246篇 |
神经病学 | 1218篇 |
特种医学 | 493篇 |
外国民族医学 | 5篇 |
外科学 | 2741篇 |
综合类 | 1744篇 |
现状与发展 | 4篇 |
一般理论 | 5篇 |
预防医学 | 1143篇 |
眼科学 | 763篇 |
药学 | 1746篇 |
12篇 | |
中国医学 | 645篇 |
肿瘤学 | 1429篇 |
出版年
2024年 | 50篇 |
2023年 | 245篇 |
2022年 | 520篇 |
2021年 | 772篇 |
2020年 | 511篇 |
2019年 | 526篇 |
2018年 | 622篇 |
2017年 | 551篇 |
2016年 | 510篇 |
2015年 | 720篇 |
2014年 | 878篇 |
2013年 | 983篇 |
2012年 | 1456篇 |
2011年 | 1558篇 |
2010年 | 949篇 |
2009年 | 763篇 |
2008年 | 1125篇 |
2007年 | 1153篇 |
2006年 | 1181篇 |
2005年 | 1147篇 |
2004年 | 933篇 |
2003年 | 798篇 |
2002年 | 781篇 |
2001年 | 549篇 |
2000年 | 545篇 |
1999年 | 495篇 |
1998年 | 198篇 |
1997年 | 199篇 |
1996年 | 165篇 |
1995年 | 118篇 |
1994年 | 116篇 |
1993年 | 84篇 |
1992年 | 209篇 |
1991年 | 190篇 |
1990年 | 166篇 |
1989年 | 146篇 |
1988年 | 117篇 |
1987年 | 114篇 |
1986年 | 92篇 |
1985年 | 62篇 |
1984年 | 43篇 |
1983年 | 31篇 |
1982年 | 45篇 |
1981年 | 40篇 |
1980年 | 35篇 |
1979年 | 36篇 |
1978年 | 32篇 |
1977年 | 19篇 |
1975年 | 20篇 |
1973年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
Reports of the incidence of postoperative deep vein thrombosis in the Chinese population of Taiwan are few in the literature. Over a 3 year period, the fibrinogen degradation products test, the pulse volume recorder, and venography were used to study 220 patients undergoing major operations at the Veterans General Hospital in Taipei, Taiwan. Deep vein thrombosis was found in 17 patients (7.7 percent). A comparison of the three diagnostic methods showed that the sensitivities of the fibrinogen degradation products test and the pulse volume recorder were 56.3 percent and 93.7 percent, respectively; the specificities, 97.4 percent and 95.7 percent, respectively; and the accuracies, 85.5 percent and 95.5 percent, respectively. These results support the combined use of the fibrinogen degradation products test and the pulse volume recorder for screening and diagnosing deep vein thrombosis. 相似文献
62.
Human trophoblast and choriocarcinoma expression of the growth
factor pleiotrophin attributable to germ-line insertion of
an endogenous retrovirus 下载免费PDF全文
63.
Guerriero S Ajossa S Lai MP Risalvato A Paoletti AM Melis GB 《Human reproduction update》1999,5(5):515-529
This review describes the usefulness of colour Doppler energy (CDE) (or power Doppler) imaging to measure vascularization in the female reproductive tract. CDE imaging is characterized by an increased sensitivity to flow, and thus may be useful in low-flow states and when optimal Doppler angles cannot be obtained. In addition, longer segments of vessels and more individual vessels can be visualized with CDE imaging. The role of CDE imaging in the evaluation of stromal vasculature in normal and in polycystic ovaries is described, and the relationship between follicular vascularity and outcome following in-vitro fertilization are discussed, together with the findings obtained from the evaluation of thecal arteriole of corpus luteum in early pregnancy. The fundamental role of CDE imaging in differentiation among ovarian masses is also reviewed. We summarize the role of CDE imaging in pregnancy, and describe two new applications of three-dimensional power Doppler sonography and the use of ultrasound contrast media. In conclusion, CDE imaging can replace conventional colour Doppler when the information on the direction of flow is not useful. Moreover, the technique appears superior to others for describing microvascular architecture and determining the presence or absence of flow. 相似文献
64.
Lai J Gouldstone A Butler JP Federspiel WJ Loring SH 《Respiratory physiology & neurobiology》2002,131(3):233-243
The pleural space is modeled in two dimensions as a thin layer of fluid separating a deformable membrane and a rigid surface containing a bump. We computed the steady-state membrane configuration and fluid pressure distribution during relative sliding of the two surfaces. For physiologically relevant values of membrane tension, shear flow-induced pressures near the bump and far-field pressure gradients are similar to those measured in vivo within the pleural space (e.g. Lai-Fook et al.) [J. Appl. Physiol.: Respirat. Environ. Exercise Physiol. 56 (1984) 1633-1639]. Deformation of the membrane over the bump suggests that the pressure field generated by the sliding motion promotes an even layer of fluid in the pleural space, preventing asperities from touching. Results also suggest a possible mechanism for pleural fluid redistribution during breathing, whereby irreversible fluid motion is associated with the deformability of the membrane. 相似文献
65.
由中、德科学中心发起、浙江大学与德国柏林洪堡大学共同主办的中德外科及基础病理新进展研讨会于2004年4月20日~22日在浙江省杭州市举行。会议由浙江大学来茂德教授和德国Humboldt大学Dietel教授主持,中、德两国共23名病理学专家参加了此次高水准国际病理学会议。会议主要涉及WHO肿瘤新分类、第6版国际抗癌联盟(UICC)TNM分期以及SARS病研究等。会议促进了双方病理学界的交流,增进了友谊,为今后中、德两国病理学界的进一步交流、合作开创了新局面。 相似文献
66.
Role of bacterial products in periodontitis: immune response in gnotobiotic rats monoinfected with Eikenella corrodens. 下载免费PDF全文
D A Johnson U H Behling C H Lai M Listgarten S Socransky A Nowotny 《Infection and immunity》1978,19(1):246-253
The development of humoral and cell-mediated immune responses to Eikenella corrodens (a bacterium that causes periodontal lesions in gnotobiotic rats) was measured and compared with the rate of appearance of macroscopic lesions. A possible inverse relationship was found. A strong cell-mediated immune response, as measured by skin reactivity and lymphocyte mitogenesis, occurred between 4 and 6 weeks after infection and subsided soon thereafter to a low response level. Humoral antibodies to endotoxin from E. corrodens could not be detected at any time. The disease developed only after the cell-mediated immune response diminished, thus suggesting that lack of an efficient immune response may permit the development of the disease. This is seemingly in contradiction to the assumption that tissue destruction in such cases is caused by the immune response and its products. We are inclined to believe, based on our findings reported here, that the lack of immune responsiveness to the bacterium and/or its products is the major causative factor in the development of periodontitis. At the same time, we wish to emphasize that occurrence of both phenomena during the long development of periodontal disease is possible. 相似文献
67.
Cell-free translation of avian erythroblastosis virus RNA yields two specific and distinct proteins with molecular weights of 75,000 and 40,000 总被引:13,自引:0,他引:13
Avian erythroblastosis virus (AEV) 28 S virion RNA was translated in vitro in cell-free reticulocyte lysates. Two AEV-specific proteins, one of 75,000 (p75) the other of 40,000 (p40) molecular weight, were detected. p75 is a fusion protein containing gag-specific and AEV-specific peptides. It appears to be translated from the 5′-end of the 28 S AEV RNA and is indistinguishable from the p75 detected in AEV-transformed cells (Hayman et al., 1979). p40 does not share sequences with any viral structural protein. It also contains peptides distinct from those of p75, but one of the five identifiable p40 peptides comigrates with one of the p75 peptides. p40 is translated from a 20 S RNA which contains the 3′-half of the AEV-specific sequences of the genome. These two proteins account for all of the coding capacity of the AEV-specific gene sequences in the 28 S AEV RNA and are candidates for leukemia-specific transforming proteins. 相似文献
68.
69.
P I Forrester P C Lai R L Hancock D M Hay F L Lorscheider 《International archives of allergy and applied immunology》1978,57(1):57-61
Immunoelectrophoresis showed that rabbit anti-human alpha-fetoprotein (AFP) cross-reacts with monkey AFP which was not detectable in the serum from an adult non-pregnant monkey. A heterologous radioimmunoassay of monkey AFP was developed using this antiserum which circumvented the need for purified monkey AFP. The radioimmunoassay is of sufficient sensitivity to measure AFP in maternal and fetal serum and amniotic fluid in the rhesus monkey. 相似文献
70.
Maeno-Hikichi Y Chang S Matsumura K Lai M Lin H Nakagawa N Kuroda S Zhang JF 《Nature neuroscience》2003,6(5):468-475
Multiple protein kinase C (PKC) isozymes are present in neurons, where they regulate a variety of cellular functions. Due to the lack of specific PKC isozyme inhibitors, it remains unknown how PKC acts on its selective target(s) and achieves its specific actions. Here we show that a PKC binding protein, enigma homolog (ENH), interacts specifically with both PKCepsilon and N-type Ca2+ channels, forming a PKCepsilon-ENH-Ca2+ channel macromolecular complex. Coexpression of ENH facilitated modulation of N-type Ca2+ channel activity by PKC. Disruption of the complex reduced the potentiation of the channel activity by PKC in neurons. Thus, ENH, by interacting specifically with both PKCepsilon and the N-type Ca2+ channel, targets a specific PKC to its substrate to form a functional signaling complex, which is the molecular mechanism for the specificity and efficiency of PKC signaling. 相似文献