全文获取类型
收费全文 | 3313篇 |
免费 | 458篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 60篇 |
儿科学 | 124篇 |
妇产科学 | 50篇 |
基础医学 | 486篇 |
口腔科学 | 61篇 |
临床医学 | 433篇 |
内科学 | 832篇 |
皮肤病学 | 84篇 |
神经病学 | 257篇 |
特种医学 | 230篇 |
外科学 | 421篇 |
综合类 | 68篇 |
一般理论 | 1篇 |
预防医学 | 198篇 |
眼科学 | 34篇 |
药学 | 169篇 |
中国医学 | 5篇 |
肿瘤学 | 269篇 |
出版年
2022年 | 21篇 |
2021年 | 41篇 |
2020年 | 26篇 |
2019年 | 36篇 |
2018年 | 81篇 |
2017年 | 74篇 |
2016年 | 73篇 |
2015年 | 68篇 |
2014年 | 102篇 |
2013年 | 133篇 |
2012年 | 175篇 |
2011年 | 155篇 |
2010年 | 124篇 |
2009年 | 125篇 |
2008年 | 138篇 |
2007年 | 128篇 |
2006年 | 102篇 |
2005年 | 109篇 |
2004年 | 132篇 |
2003年 | 111篇 |
2002年 | 76篇 |
2001年 | 124篇 |
2000年 | 121篇 |
1999年 | 80篇 |
1998年 | 99篇 |
1997年 | 76篇 |
1996年 | 86篇 |
1995年 | 71篇 |
1994年 | 54篇 |
1993年 | 63篇 |
1992年 | 70篇 |
1991年 | 67篇 |
1990年 | 65篇 |
1989年 | 46篇 |
1988年 | 64篇 |
1987年 | 69篇 |
1986年 | 48篇 |
1985年 | 46篇 |
1984年 | 50篇 |
1983年 | 48篇 |
1982年 | 26篇 |
1981年 | 36篇 |
1980年 | 26篇 |
1979年 | 32篇 |
1978年 | 25篇 |
1977年 | 32篇 |
1976年 | 24篇 |
1968年 | 21篇 |
1967年 | 17篇 |
1966年 | 18篇 |
排序方式: 共有3782条查询结果,搜索用时 0 毫秒
71.
72.
73.
Rejection sensitivity – the tendency to expect, perceive, and overreact to rejection by others – is linked with individuals' expectations that their romantic partners' behaviors have negative intent, even if, perhaps, such behaviors could be considered neutral when observed by another. The aim of the present study was to test this proposition, derived from rejection sensitivity theory, using a Video-Recall Procedure with adolescent couples in the US (N = 386 adolescents, 50% girls). We examined whether adolescents who were more sensitive to rejection perceived their romantic partners' behaviors as more conflictual than when viewed by trained, third-party observers. Findings suggest that, at the micro-analytic level, higher rejection sensitivity is associated with adolescents' heightened perception of their romantic partners as conflictual when compared to observers, who more often coded the same behaviors as neutral rather than conflictual. Implications for adolescent mental health and well-being are discussed. 相似文献
74.
Comparison of Bilateral vs. Staged Unilateral Deep Brain Stimulation (DBS) in Parkinson's Disease in Patients Under 70 Years of Age
下载免费PDF全文
![点击此处可从《Neuromodulation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
75.
76.
77.
Expression of fibrinogen receptors during activation and subsequent desensitization of human platelets by epinephrine 总被引:2,自引:0,他引:2
Epinephrine causes platelet aggregation and secretion by interacting with alpha 2-adrenergic receptors on the platelet surface. Platelet aggregation requires the binding of fibrinogen to a specific receptor on the membrane glycoprotein IIb-IIIa complex. Although the IIb-IIIa complex is identifiable on the surface of resting platelets, the fibrinogen receptor is expressed only after platelet activation. The current studies were designed to examine the effect of occupancy of platelet alpha 2-adrenergic receptors by epinephrine on the expression of fibrinogen receptors and on the aggregation of platelets. The ability of epinephrine to induce the expression of fibrinogen receptors was studied under two different conditions: acute stimulation (less than 1 min) and prolonged stimulation (50 to 90 min), the latter of which is associated with a reduction or "desensitization" of the platelet aggregation response. Expression of the fibrinogen receptor was monitored with 125I-fibrinogen as well as with 125I-PAC-1 (PAC-1), a monoclonal antibody that binds to the glycoprotein IIb-IIIa complex only after platelets are activated. Epinephrine caused an immediate increase in PAC-1 and fibrinogen binding that was dependent on occupancy of the alpha 2-receptor by epinephrine and on the presence of extracellular free Ca (KCa = 30 mumol/L). By itself, 1 mmol/L Mg was unable to support induction of the fibrinogen receptor by epinephrine. However, it did decrease the Ca requirement by about two orders of magnitude. Prolonged stimulation of unstirred platelets by epinephrine led to a 70% decrease in the aggregation response when the platelets were subsequently stirred. Despite their decreased aggregation response, desensitized platelets bound PAC-1 and fibrinogen normally, indicating that the loss of aggregation was not due simply to a decrease in fibrinogen receptor expression. Although desensitization was not affected by pretreatment of the platelets with aspirin, it was partially prevented when extracellular Ca was chelated by EDTA during the long incubation with epinephrine. These studies demonstrate that once platelet alpha 2-adrenergic receptors are occupied by epinephrine, extracellular Ca is involved in initiating the aggregation response by supporting the induction of the fibrinogen receptor and the binding of fibrinogen. Furthermore. Ca-dependent reactions subsequent to fibrinogen binding may be necessary for maximal platelet aggregation and are impaired when platelets become desensitized to epinephrine. 相似文献
78.
Glycoprotein Ib and glycoprotein IX are fully complexed in the intact platelet membrane 总被引:3,自引:6,他引:3
Two new murine monoclonal antibodies, AK 1 and SZ 1, reactive with the human platelet glycoprotein (GP) Ib-IX complex have been produced by the hybridoma technique. Both AK 1 and SZ 1 immunoprecipitated the GP Ib-IX complex from Triton X-100-solubilized, periodate-labeled platelets. With trypsinized, labeled platelets, AK 1, SZ 1, and FMC 25 (epitope on GP IX) immunoprecipitated a membrane-bound proteolytic fragment of the GP Ib-IX complex consisting of GP IX and an congruent to 25,000 mol wt remnant of the alpha-chain of GP lb disulfide-linked to the beta-subunit. Unexpectedly, although AK 1 and SZ 1 immunoprecipitated purified GP Ib-IX complex, neither antibody immunoprecipitated the individual components of this complex, GP Ib or GP IX. When GP Ib and GP IX were recombined, however, AK 1 and SZ 1 again immunoprecipitated the reformed complex, strongly suggesting that both antibodies were recognizing an epitope present only on the intact complex. Cross-blocking studies indicated that AK 1 and SZ 1 recognized a very similar or identical epitope that was proximal to the epitope for FMC 25. Both AK 1 and SZ 1 bound to a similar number of binding sites (congruent to 25,000) on intact platelets as monoclonal antibodies directed against either GP lb or GP IX. The combined data suggests that GP lb and GP IX are fully complexed in the intact platelet membrane. 相似文献
79.
80.
Normal motor learning during pharmacological prevention of Purkinje cell long-term depression 总被引:11,自引:0,他引:11
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Welsh JP Yamaguchi H Zeng XH Kojo M Nakada Y Takagi A Sugimori M Llinás RR 《Proceedings of the National Academy of Sciences of the United States of America》2005,102(47):17166-17171
Systemic delivery of (1R-1-benzo thiophen-5-yl-2[2-diethylamino)-ethoxy] ethanol hydrochloride (T-588) prevented long-term depression (LTD) of the parallel fiber (PF)-Purkinje cell (PC) synapse induced by conjunctive climbing fiber and PF stimulation in vivo. However, similar concentrations of T-588 in the brains of behaving mice and rats affected neither motor learning in the rotorod test nor the learning of motor timing during classical conditioning of the eyeblink reflex. Rats given doses of T-588 that prevented PF-PC LTD were as proficient as controls in learning to adapt the timing of their conditioned eyeblink response to a 150- or 350-ms change in the timing of the paradigm. The experiment indicates that PF-PC LTD under control of the climbing fibers is not required for general motor adaptation or the learning of response timing in two common models of motor learning for which the cerebellum has been implicated. Alternative mechanisms for motor timing and possible functions for LTD in protection from excitotoxicity are discussed. 相似文献