全文获取类型
收费全文 | 33365篇 |
免费 | 2137篇 |
国内免费 | 104篇 |
专业分类
耳鼻咽喉 | 496篇 |
儿科学 | 820篇 |
妇产科学 | 394篇 |
基础医学 | 4253篇 |
口腔科学 | 488篇 |
临床医学 | 3328篇 |
内科学 | 7750篇 |
皮肤病学 | 240篇 |
神经病学 | 3445篇 |
特种医学 | 1366篇 |
外科学 | 5476篇 |
综合类 | 305篇 |
一般理论 | 73篇 |
预防医学 | 2311篇 |
眼科学 | 428篇 |
药学 | 2041篇 |
中国医学 | 22篇 |
肿瘤学 | 2370篇 |
出版年
2023年 | 166篇 |
2022年 | 284篇 |
2021年 | 737篇 |
2020年 | 420篇 |
2019年 | 722篇 |
2018年 | 877篇 |
2017年 | 609篇 |
2016年 | 692篇 |
2015年 | 796篇 |
2014年 | 1165篇 |
2013年 | 1490篇 |
2012年 | 2430篇 |
2011年 | 2479篇 |
2010年 | 1431篇 |
2009年 | 1173篇 |
2008年 | 2237篇 |
2007年 | 2309篇 |
2006年 | 2237篇 |
2005年 | 2249篇 |
2004年 | 2009篇 |
2003年 | 1919篇 |
2002年 | 1873篇 |
2001年 | 321篇 |
2000年 | 264篇 |
1999年 | 320篇 |
1998年 | 378篇 |
1997年 | 299篇 |
1996年 | 249篇 |
1995年 | 254篇 |
1994年 | 213篇 |
1993年 | 191篇 |
1992年 | 189篇 |
1991年 | 197篇 |
1990年 | 173篇 |
1989年 | 145篇 |
1988年 | 130篇 |
1987年 | 132篇 |
1986年 | 123篇 |
1985年 | 137篇 |
1984年 | 165篇 |
1983年 | 130篇 |
1982年 | 150篇 |
1981年 | 126篇 |
1980年 | 104篇 |
1979年 | 72篇 |
1978年 | 76篇 |
1977年 | 64篇 |
1976年 | 49篇 |
1974年 | 47篇 |
1971年 | 43篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
The haemodynamic effects of propofol and thiopentone for induction of caesarean section 总被引:3,自引:0,他引:3
Forty Chinese women for elective caesarean section received either propofol 2 mg.kg-1 or thiopentone 4 mg.kg-1 for induction of general anaesthesia. Systolic, mean and diastolic arterial pressures and heart rate were recorded non-invasively every minute for ten minutes. Post-induction arterial pressures were similar to pre-induction values with no differences between thiopentone and propofol. Following intubation, the rise in systolic arterial pressure was greater in the thiopentone group, 32.1 mmHg (SD 23.7) compared with the propofol group, 17.4 mmHg (SD 23.8), (P less than 0.05). In the thiopentone group, arterial pressures were slower in returning to baseline values. Heart rate was initially elevated in both groups to the same degree. At caesarean section, induction with propofol causes less variation in arterial pressure than thiopentone. Hypotension is probably prevented by the coincident stimulus of rapid sequence induction. Neonatal Apgar scores were similar between the two groups. 相似文献
72.
Inflammatory mediators and the destruction of bone 总被引:3,自引:0,他引:3
Gregory R. Mundy 《Journal of periodontal research》1991,26(3):213-217
Bone is remodelled by the coordinated actions of osteoclasts and osteoblasts. Cellular remodelling occurs in discrete packets of bone, and is regulated by local cytokines produced in the environment of the remodelling cells. These cytokines are secreted by immune cells and by bone cells. In addition, some growth regulatory factors are incorporated into the noncollagenous bone matrix and are released in an active form when bone is stimulated to resorb. Complex interactions between these cytokines and their target cells are responsible for the normal delicate balance between bone resorption and bone formation, and disorders of bone loss are due to imbalances between the rates of resorption and formation. 相似文献
73.
74.
MD MS Gregory L Larkin PhD John Moskop MD FACEP Arthur Sanders MD JD FACEP Arthur Derse 《Annals of emergency medicine》1994,24(6)
Confidentiality is a promise rooted in tradition, law andmedical ethics. Emergency physicians treat a variety of patients to whom confidentiality is of vital importance: employees, celebrities, victims of violence or disaster, minors, students, criminals, drug abusers, and patients with STDs. EDs should develop methods of ensuring confidentiality for all patients.34Although confidentiality is an important principle thatshould be respected and guarded, it is not absolute. Various laws mandate disclosure of certain patient information; in addition, an overriding moral duty may occasionally require, a breach of confidentiality. As Beauchamp and Childress noted, “the therapeutic role may sometimes have to yield to ones role as citizen and as protector of the interests of others”.19 In general, however, circumstances requiring a breach of confidentiality are rare. 相似文献
75.
K A Knox M Finney A E Milner C D Gregory M J Wakelam R H Michell J Gordon 《International journal of cancer. Journal international du cancer》1992,52(6):959-966
Spontaneous apoptosis in germinal-centre (GC) B cells can be prevented by treatment with anti-immunoglobulin (Ig). By contrast, susceptible group-I Burkitt lymphoma (BL) cells can be driven to apoptosis by anti-Ig. The second-messenger pathways involved in the regulation of apoptosis in GC B lymphocytes and in BL cell lines were studied using pharmacological agonists or inhibitors of intracellular calcium ([Ca2+]i) and protein kinase C (PKC). Anti-Ig was found to mobilize Ca2+ in group-I cells. Pre-incubation with the Ca2+ chelator EGTA partially reduced apoptosis induced by anti-Ig or by Ca2+ ionophore in group-I BL cells. Activation of PKC with phorbol ester reduced such Ca(2+)-driven programmed cell death (PCD) to control levels of apoptosis. Apoptosis in group-I BL cell lines could also be triggered by the kinase inhibitors staurosporine and Ro-31-8220 at concentrations selective for PKC activity. Expression of the bcl-2 protein in BL group-I cells following gene transfer affords protection from apoptosis induced by ionomycin or anti-Ig. In the present study, bcl-2 was additionally found to protect from apoptosis driven by staurosporine. The high levels of spontaneous apoptosis exhibited by normal GC B cells were reduced, but not abrogated, by co-culture with phorbol ester. These results indicate that, in group-I BL cells, imbalance in the phosphoinositide pathway of signalling, in favour of [Ca2+]i and away from PKC, results in apoptosis: constitutive phosphorylation of key proteins by PKC may therefore suppress apoptosis in BL as well as in GC B cells. 相似文献
76.
cAMP production was investigated in retinal pigment epithelium (RPE) cells isolated from normal rats and from rats with an inherited retinal dystrophy (Rdy/p+). In normal RPE cells, 5'-[N-Ethylcarboxamido]-adenosine (A2 receptors) produced a fivefold increase in the level of cyclic adenosine monophosphate (cAMP) over basal levels. However, only a onefold increase in cAMP was observed in dystrophic cells. cAMP production by prostaglandins E1 and E2 (prostaglandin receptors) in dystrophic RPE cells was only 29-38% of the level observed in normal cells. Direct stimulation of adenylyl cyclase by 10 mumol/l forskolin increased cAMP levels in normal RPE cells by 90 fold over basal, but only by sixfold in the dystrophic cells. These data suggest there may be a defect in the adenylyl cyclase signaling pathway in dystrophic RPE cells. 相似文献
77.
78.
Thomas Patrick S. Jr; Fraley Gregory S.; Damian Vincent; Woodke Lillie B.; Zapata Francisco; Sopher Bryce L.; Plymate Stephen R.; La Spada Albert R. 《Human molecular genetics》2006,15(19):2972
Human Molecular 相似文献
79.
80.