全文获取类型
收费全文 | 2200篇 |
免费 | 34篇 |
专业分类
2234篇 |
出版年
2015年 | 18篇 |
2014年 | 29篇 |
2013年 | 114篇 |
2012年 | 43篇 |
2011年 | 42篇 |
2010年 | 28篇 |
2009年 | 37篇 |
2008年 | 43篇 |
2007年 | 50篇 |
2006年 | 42篇 |
2005年 | 42篇 |
2004年 | 46篇 |
2003年 | 43篇 |
2002年 | 58篇 |
2001年 | 25篇 |
2000年 | 53篇 |
1999年 | 27篇 |
1998年 | 17篇 |
1997年 | 24篇 |
1996年 | 44篇 |
1995年 | 24篇 |
1994年 | 37篇 |
1993年 | 41篇 |
1992年 | 34篇 |
1991年 | 51篇 |
1990年 | 38篇 |
1989年 | 45篇 |
1988年 | 26篇 |
1987年 | 47篇 |
1986年 | 38篇 |
1985年 | 34篇 |
1984年 | 55篇 |
1983年 | 27篇 |
1982年 | 33篇 |
1981年 | 41篇 |
1980年 | 28篇 |
1979年 | 28篇 |
1978年 | 22篇 |
1977年 | 31篇 |
1976年 | 24篇 |
1975年 | 38篇 |
1974年 | 25篇 |
1972年 | 17篇 |
1971年 | 18篇 |
1943年 | 30篇 |
1939年 | 22篇 |
1938年 | 21篇 |
1937年 | 27篇 |
1935年 | 28篇 |
1930年 | 21篇 |
排序方式: 共有2234条查询结果,搜索用时 0 毫秒
31.
Angele McGrady Ph.D. M.Ed. Patricia Ann Nadsady Cathleen Schumann-Brzezinski 《Applied psychophysiology and biofeedback》1991,16(4):399-411
The usefulness of biofeedback-assisted relaxation as an adjunct or substitute for pharmacotherapy in essential hypertension can be enhanced if the effects are shown to persist after formal treatment has ended. Patients with essential hypertension successfully treated with biofeedback-assisted relaxation were recalled for follow-up yearly after the termination of treatment. Twenty-six of 40 patients met the BP criterion for success. At one-, two-, and three-year follow-up, 31%, 38%, and 27% of the successful completers continued to meet the criterion for success. The pretreatment-posttreatment decreases in BP were accompanied by decreases in forehead muscle tension and urinary cortisol. Forehead muscle tension, urinary cortisol, and anxiety levels were significantly lower than pretreatment one year after the end of treatment. Self-report data were used to assess continued relaxation practice. No relationship was found between practice and any other dependent measure. It appears that some patients trained in biofeedback-assisted relaxation can maintain lowered blood pressure, muscle tension, anxiety, and cortisol levels over the long term; however, the role of relaxation practice in maintaining these lowered levels remains unclear. 相似文献
32.
S Spampinato E Speroni M Canossa G Sciarretta P Malaguti S Ferri 《Regulatory peptides》1992,41(2):131-138
Dynorphin B-like immunoreactivity (ir-dyn B) was measured by a validated radio-immunoassay in gastroduodenal biopsy specimens from control and gallstone patients. Levels were significantly lower in acetic acid extracts of specimens of the transverse portion of the duodenum from gallstone patients. Gel permeation chromatography showed that almost all ir-dyn B in duodenal samples corresponded to a molecular form co-eluting with authentic dyn B. Duodenal extracts from gallstone patients had less of this form. Reverse-phase high performance liquid chromatography of the pooled gel chromatography fractions showed up a molecular form with the same retention time as synthetic dyn B which was significantly less in fractions from duodenal extracts of gallstone patients. These results indicate the occurrence of dyn B in the human gastrointestinal tract; however, at this stage of our understanding, no causal relationship can be demonstrated with functional alterations of the biliary tree. 相似文献
33.
34.
35.
36.
37.
M.D. J.J. Amy M.D. M. Dierick M.D. Ph.D. M. Thiery M.D. A. Remouchamps 《Prostaglandins & other lipid mediators》1975,10(4):395-403
Present study was prompted by the report from another center on the occasional occurrence of convulsions and abnormal electroencephalogram (E.E.G.) patterns in women aborted with intraamniotic prostaglandin F2α (PGF2α). Fifty four subjects were investigated by means of an E.E.G. taken before and after initiation of PGE2 administration. They included pregnant and non-pregnant patients, nearly half (23) of whom were known epileptics. One seizure was observed during PG administration in a man with daily psychomotor attacks who had not taken his anticonvulsants on the day the test was performed. PGE2 caused no alteration of the E.E.G. in subjects with a normal control tracing; in those with an abnormal E.E.G., a deterioration was seen in one and an improvement in three. It is concluded that PGE2 is not epileptogenic at doses required for termination of pregnancy. 相似文献
38.
Uric Acid Amplifies Aβ Amyloid Effects Involved in the Cognitive Dysfunction/Dementia: Evidences From an Experimental Model In Vitro 下载免费PDF全文
39.
Expression of cell type-specific markers during pancreatic development in the mouse: implications for pancreatic cell lineages 总被引:2,自引:0,他引:2
Summary The islet cells of the mammalian pancreas are comprised of four different endocrine cell types, each containing a specific hormone. Islet cells also contain two enzymes of the catecholamine biosynthetic pathway: tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC). The cell lineage relationships of these different cell types have not been examined and it is not known whether, during development, they originate from the same or from different precursor populations. In this study we used immunocytochemical procedures to determine whether developing pancreatic cells express markers common to endocrine and exocrine cell types. We found that acinar cell precursors express AADC prior to the appearance of an exocrine marker and that the expression of AADC in acinar cells persists throughout embryogenesis to the first month of postnatal life. At this time, acinar cells do not contain AADC. We also found that exocrine cells containing AADC never express other islet-cell markers. These findings suggest that while acinar and islet cells both arise from precursor cells containing AADC, these progenitor cells do not express a combined endocrine-exocrine phenotype. 相似文献
40.
Induction of tumoricidal activity is one of the major functions of activated macrophages. Our previous study demonstrated that P388D1 murine macrophage-like cells secreted a plasmacytoma cytotoxic factor (PCF) that selectively killed certain tumor cell lines including MOPC-315 plasmacytoma in vitro. Our subsequent studies demonstrated that PCF killed MOPC-315 cells by induction of apoptosis. In this report, the involvement of Fas and Fas ligand (FasL) in PCF-induced apoptosis was investigated. Results suggest that expression of Fas mRNA time-dependently increased in PCF-treated cells and reached an optimal level after 36 h of treatment. The augmented effect of PCF on Fas mRNA expression was significantly reduced by the addition of CB7.C2, an anti-PCF monoclonal antibody. The expression of FasL mRNA was also induced by PCF and reached an optimal level at 24 h, but sharply decreased after 36 h of treatment. Caspase-3 is one of the proteolytic enzymes that can be activated by the Fas-FasL interaction. In our studies, the enzymatic activity of caspase-3 was significantly induced by PCF after 6 h of treatment and reached an optimal level at 12 h. The augmented effect of PCF on caspase activity was significantly reduced by the addition of CB7.C2 and the caspase-3-specific inhibitor, DEVD-fmk. Therefore, PCF-treated plasmacytoma cells might undergo apoptosis via interaction between Fas and FasL. 相似文献