全文获取类型
收费全文 | 10446篇 |
免费 | 708篇 |
国内免费 | 24篇 |
专业分类
耳鼻咽喉 | 54篇 |
儿科学 | 513篇 |
妇产科学 | 271篇 |
基础医学 | 1118篇 |
口腔科学 | 674篇 |
临床医学 | 955篇 |
内科学 | 1842篇 |
皮肤病学 | 154篇 |
神经病学 | 850篇 |
特种医学 | 553篇 |
外国民族医学 | 2篇 |
外科学 | 1610篇 |
综合类 | 239篇 |
一般理论 | 6篇 |
预防医学 | 795篇 |
眼科学 | 242篇 |
药学 | 628篇 |
1篇 | |
中国医学 | 76篇 |
肿瘤学 | 595篇 |
出版年
2021年 | 136篇 |
2019年 | 109篇 |
2018年 | 140篇 |
2017年 | 121篇 |
2016年 | 105篇 |
2015年 | 127篇 |
2014年 | 197篇 |
2013年 | 283篇 |
2012年 | 351篇 |
2011年 | 418篇 |
2010年 | 268篇 |
2009年 | 253篇 |
2008年 | 417篇 |
2007年 | 402篇 |
2006年 | 421篇 |
2005年 | 386篇 |
2004年 | 396篇 |
2003年 | 313篇 |
2002年 | 321篇 |
2001年 | 290篇 |
2000年 | 277篇 |
1999年 | 243篇 |
1998年 | 129篇 |
1997年 | 136篇 |
1996年 | 134篇 |
1995年 | 124篇 |
1994年 | 121篇 |
1993年 | 94篇 |
1992年 | 227篇 |
1991年 | 221篇 |
1990年 | 222篇 |
1989年 | 256篇 |
1988年 | 226篇 |
1987年 | 246篇 |
1986年 | 213篇 |
1985年 | 189篇 |
1984年 | 182篇 |
1983年 | 122篇 |
1981年 | 92篇 |
1980年 | 89篇 |
1979年 | 142篇 |
1978年 | 116篇 |
1977年 | 100篇 |
1976年 | 115篇 |
1975年 | 106篇 |
1974年 | 112篇 |
1973年 | 132篇 |
1972年 | 103篇 |
1971年 | 87篇 |
1957年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
891.
892.
Tongue and oropharynx: findings on MR imaging 总被引:6,自引:0,他引:6
Lufkin RB; Wortham DG; Dietrich RB; Hoover LA; Larsson SG; Kangarloo H; Hanafee WN 《Radiology》1986,161(1):69-75
Ten healthy subjects and 44 patients with diseases of the tongue or oropharynx were studied with magnetic resonance (MR) imaging. Axial, coronal, and sagittal images with a thickness of 4 mm were obtained with a pixel size of 0.75 X 0.75 mm on a 256 matrix. Nineteen of the patients underwent computed tomography (CT). Nine of those patients later had surgery, and the specimens were obtained for organ sectioning. These three studies as well as clinical history and physical examination findings were correlated. MR imaging was equal to or better than CT in those patients having both examinations. However, neither CT nor MR allowed recognition of histologic features or detection of microscopic spread of disease. Direct coronal and sagittal imaging planes on MR imaging allowed visualization of intrinsic tongue musculature, not possible with CT; this was important in recognizing subtle tumor extension. For these reasons, MR is the imaging method of choice for studying diseases of the tongue and oropharynx. 相似文献
893.
Direct sagittal computed tomographic scanning (DSCT) of the shoulder was performed in 42 symptomatic patients, six healthy volunteers, and two cadaver shoulders. Axial CT scanning and double-contrast arthrography with plain radiographs were performed in 41 patients for comparison. DSCT enabled correct identification of 27 of 29 lesions in 24 patients. Seventeen patients had normal shoulders. Axial CT scanning and DSCT together enabled correct identification of all lesions and were markedly superior to plain-film arthrography. DSCT enabled diagnosis of all cases of complete rotator cuff tear plus three cases of incomplete tear and three of rotator cuff atrophy not identified by the other techniques. Axial CT scanning was better than DSCT for diagnosis of Bankart lesions. 相似文献
894.
Antineoplastic drugs (methotrexate, 5-fluorouracil, adriamycin) arrest the proliferation of Ehrlich ascites tumor cells in mice but have no influence on L-leucine uptake in vitro. Tamoxifen does not influence either process. Estradiol increases both the cellular proliferation and the amino acid uptake. The absence of estrogen receptors in the cells indicates that the hormone acts on cellular proliferation through mechanisms other than activation of DNA replication, such as stimulation of amino acid transport. 相似文献
895.
Effects of pregnancy on muscarinic receptor density and function in the rabbit urinary bladder. 总被引:1,自引:0,他引:1
The contractile response of the rabbit urinary bladder to field stimulation consists of both cholinergic and purinergic components. In general, approximately 60% of the contractile response to field stimulation is cholinergic and 40% is purinergic. Although the purinergic response represents a significant proportion of the initial (phasic) pressure response to field stimulation of the isolated whole bladder, it contributes only 10-15% of the ability of field stimulation to empty the bladder. The current study investigates the effects of pregnancy on the contractile responses of the isolated urinary bladder to cholinergic and purinergic stimulation. The results of these studies indicate that pregnancy induces substantial changes in the physiology and pharmacology of the urinary bladder. The following data are consistent with the theory that pregnancy substantially increases the relative purinergic component of the response to field stimulation (and presumably neuronal stimulation): (1) there was a significantly greater response of the bladders isolated from pregnant rabbits to low-frequency field stimulation; (2) atropine was more effective at inhibiting the pressure generation of bladders isolated from virgin female rabbits; (3) field stimulation was more effective at emptying bladders isolated from virgin female rabbits; (4) the response of the bladders from pregnant rabbits to bethanechol was significantly reduced, whereas the response to ATP was significantly increased. In addition to these effects of pregnancy on bladder physiology, pregnancy induced a 50% decrease in the muscarinic receptor density of the urinary bladder body, which correlated very well with the 50% decrease in the contractile response to bethanechol. 相似文献
896.
Image processing and volume rendering have been applied to magnetic resonance (MR) images to produce three-dimensional views of the surface of the brain. Four healthy volunteers and 17 patients with a variety of disorders underwent MR imaging of the head, and these images were processed and subjected to volume rendering. The resulting three-dimensional views depict abnormalities of the brain surface, as well as important landmarks of normal brain surface anatomy such as precentral, postcentral, superior temporal, and inferior frontal gyri, which are difficult to identify on cross-sectional images. 相似文献
897.
To investigate the possibility that learning of skills (ie, procedural memory) is preserved during posttraumatic amnesia, 16 amnesic survivors of severe closed head injury and 16 control subjects were studied. Procedural learning tasks included mirror reading, mazes, and a pursuit rotor task that involved tracking a rotating target. Declarative memory was assessed by testing recognition of the words used in mirror reading and a questionnaire concerning details of the previous testing session. Learning was evaluated on 3 consecutive days and a fourth session was scheduled after resolution of posttraumatic amnesia. Despite stable impairment of declarative memory during posttraumatic amnesia, the performance of head-injured patients improved across sessions on all procedural tasks and showed transfer to testing after resolution of posttraumatic amnesia. 相似文献
898.
Urethral strips provide a sensitive method for quantitative pharmacology; however, it is not clear if the physiological response of the whole urethra to pharmacological agents can be extrapolated from these data. The intent of this study was to investigate whether the linear contraction of strips is consistent with the ability of the intact urethra to alter resistance to flow. To measure the effect of drugs on the ability of the intact urethra to alter resistance to flow in the absence of endogenous influences, we developed an in vitro whole rabbit urethra model. We characterized the effect of norepinephrine in the absence and presence of alpha-adrenergic antagonists (prazosin, yohimbine, and LY253352) on intraurethral pressure which was measured during constant saline infusion using a Statham pressure transducer. We compared this to the contractile function of urethral strips. The pA2 values for alpha-adrenergic antagonists, LY253352, prazosin, and yohimbine were 8.17 +/- 1.5, 6.49 +/- 1.2, and 5.58 +/- 0.9, respectively, as determined in the whole urethra. The pA2 values for these antagonists determined in urethral strips were as follows: LY253352 8.72 +/- 1.2; prazosin 7.52 +/- 1.5, and yohimbine 5.6 +/- 0.84. Pharmacologically, the whole urethra model and isolated strips appeared to respond similarly to alpha-adrenergic agonists and antagonists, and thus both models would be suitable for pharmacological studies on the normal urethra. 相似文献
899.
L Ewing-Cobbs H S Levin H M Eisenberg J M Fletcher 《Journal of clinical and experimental neuropsychology》1987,9(5):575-592
Fifty-six children and adolescents who sustained a closed-head injury were divided into two groups based on neurological criteria. Language performance was assessed using the Neurosensory Center Comprehensive Examination for Aphasia during the subacute stage of recovery. Naming, expressive, and written language were more impaired than receptive-language functions. At least 20% of the sample exhibited deficits on measures of describing the function of objects, sentence repetition, verbal associative fluency, writing to dictation, and copying sentences. No sparing of function was observed in children relative to adolescents. Moreover, written-language performance was more depressed in children than adolescents. Results were discussed in terms of acquired aphasia in children and posttraumatic linguistic deficits in adults. 相似文献
900.