全文获取类型
收费全文 | 1031281篇 |
免费 | 77573篇 |
国内免费 | 2697篇 |
专业分类
耳鼻咽喉 | 13435篇 |
儿科学 | 35334篇 |
妇产科学 | 29049篇 |
基础医学 | 149268篇 |
口腔科学 | 28276篇 |
临床医学 | 94024篇 |
内科学 | 200479篇 |
皮肤病学 | 23330篇 |
神经病学 | 82203篇 |
特种医学 | 39670篇 |
外国民族医学 | 306篇 |
外科学 | 154919篇 |
综合类 | 24154篇 |
一般理论 | 427篇 |
预防医学 | 80899篇 |
眼科学 | 23230篇 |
药学 | 74202篇 |
3篇 | |
中国医学 | 2052篇 |
肿瘤学 | 56291篇 |
出版年
2019年 | 8189篇 |
2018年 | 11661篇 |
2017年 | 8996篇 |
2016年 | 10170篇 |
2015年 | 11529篇 |
2014年 | 15832篇 |
2013年 | 23874篇 |
2012年 | 31598篇 |
2011年 | 33514篇 |
2010年 | 19938篇 |
2009年 | 18769篇 |
2008年 | 31064篇 |
2007年 | 32691篇 |
2006年 | 33033篇 |
2005年 | 31704篇 |
2004年 | 30867篇 |
2003年 | 29549篇 |
2002年 | 28447篇 |
2001年 | 47204篇 |
2000年 | 48272篇 |
1999年 | 40549篇 |
1998年 | 11488篇 |
1997年 | 10348篇 |
1996年 | 10407篇 |
1995年 | 9952篇 |
1994年 | 9248篇 |
1993年 | 8638篇 |
1992年 | 32398篇 |
1991年 | 31600篇 |
1990年 | 31137篇 |
1989年 | 30021篇 |
1988年 | 27294篇 |
1987年 | 27450篇 |
1986年 | 25519篇 |
1985年 | 24696篇 |
1984年 | 18480篇 |
1983年 | 15601篇 |
1982年 | 9383篇 |
1981年 | 8440篇 |
1979年 | 16926篇 |
1978年 | 12284篇 |
1977年 | 10365篇 |
1976年 | 9801篇 |
1975年 | 10224篇 |
1974年 | 12366篇 |
1973年 | 11897篇 |
1972年 | 10934篇 |
1971年 | 10150篇 |
1970年 | 9398篇 |
1969年 | 8747篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
R W Hertle A B Leahey S Bloom D B Schaffer S Bartlett 《Ophthalmic plastic and reconstructive surgery》1990,6(4):278-282
Chorioretinal folds have been reported as a result of many intraocular and extraocular inflammatory processes or tumors. Visual loss is usually secondary to a combination of the underlying process and chorioretinal folds involving the macula. We report a patient who developed decreased vision, metamorphopsia, chorioretinal folds, and a lamellar macular hole secondary to global compression by a bone fragment. The chorioretinal folds regressed and his vision stabilized following surgical decompression. Chorioretinal folds and lamellar macular hold formation are previously unrecognized complications of reconstructive craniofacial surgery. 相似文献
82.
83.
SRIVASTAVA Z. I.; MATHUR N.; RASTOGI S. K.; GUPTA B. N. 《Occupational medicine (Oxford, England)》1988,38(4):134-136
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease.
Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India 相似文献
84.
The composition of the clientele from an ophthalmological practitioner's office is described with special reference to the occurrence of glaucoma and disc haemorrhages (h in singular; hh in plural). This study could not be planned as an epidemiological survey and gives no clue to sensitivity or specificity of hh in glaucoma. During a period of about 10 years ending with 1986 there were 731 patients with h and/or glaucoma. When detected, 185 patients had h but no glaucoma, 33 had both h and glaucoma and 513 had glaucoma but no h. During the follow-up period hh were detected in 83 cases of glaucoma, and glaucoma developed in 27 cases with hh. The detection rate of hh among glaucoma was low but steady, indicating that hh may occur at any stage of the glaucoma process. This study shows no predilection for hh in cases with general hypertension or diabetes, nor is the frequency of hh among pseudoexfoliation cases significantly lower than among cases without this stigma. 相似文献
85.
Isotretinoin (Accutane Capsules) is a synthetic vitamin A compound used for treatment of recalcitrant cystic acne. It has numerous ocular toxic side effects which include anterior segment inflammation, dry eye syndrome, contact lens intolerance, altered refraction, photosensitivity, and reduced night vision. Eye care practitioners should be aware of these potential side effects and be prepared to communicate with the prescribing physician if side effects present. 相似文献
86.
Although extracellular matrix (ECM) glycoproteins play important roles in neural development, their levels are generally believed to decrease in the adult brain. Immunohistochemical analysis indicates that the anti-adhesive ECM glycoprotein SPARC/osteonectin, which contains a follistatin ‘module’, is expressed in the adult rabbit nervous system. In the cerebellum, SPARC is present in Bergmann glia, with a strong signal along their radial fibres. SPARC, while enriched in membrane fractions, is not a transmembrane protein. In the hippocampus, colocalization of SPARC is observed in cells which express the astrocytic marker GFAP. The expression of SPARC by a subset of astrocytes, particularly in synaptic enriched areas, suggests a continuing role for the ECM in the adult brain. 相似文献
87.
88.
89.
Localized proton magnetic resonance spectroscopy of a cerebellar tumor in a two-year-old child 总被引:1,自引:0,他引:1
B. Wilken G. Helms H. J. Christen J. Bhnk J. Frahm F. Hanefeld 《Child's nervous system》1996,12(10):626-629
Noninvasive localized proton magnetic resonance spectroscopy (MRS) was used for differential diagnosis of a focal brain lesion in a 2.5-year-old girl. The clinical signs were a mild head tilt and neck pain. Magnetic resonance imaging (MRI) revealed a lesion in the right hemisphere of the cerebellum, but its nature remained obscure. In this lesion quantitative determinations of cerebral metabolites by fully relaxed, short-echo-time proton MRS revealed markedly lowered N-acetylaspartate (NAA) and pronounced elevations of choline-containing compounds (Cho) and myo-inositol (Ins), whereas metabolite concentrations in cortical gray matter and white matter were within normal ranges. The metabolite pattern of the lesion indicated loss of vital neuroaxonal tissue (low NAA) and enhanced glial proliferation (high Cho and Ins), which, together with the MRI morphology, suggested a brain tumor. The diagnosis was established by neurosurgical exploration and total extirpation of the tumor. Histology confirmed an astrocytoma (WHO II). After 2 weeks' recovery the child was discharged with no neurological signs. 相似文献
90.
Confounders contributing to the reported associations of coffee or caffeine with disease 总被引:2,自引:0,他引:2
G B Schreiber M Robins C E Maffeo M N Masters A P Bond D Morganstein 《Preventive medicine》1988,17(3):295-309
The role of caffeine or coffee in causing or promoting the incidence of serious disease is equivocal. Two design factors may account for the discrepancies in reported findings on the effects of coffee drinking: (a) imprecision of measurement and (b) confounding variables. A study of 2,714 white U.S. adults disclosed that, of 32 risk factors analyzed by linear and logistic regression, only sex and cigarette smoking were found to be important potential confounders of caffeine and coffee intake. Partial R2 values of the other 30 risk factors were relatively small and were inconsistent for each sex. It is unlikely that any of these factors could explain any of the reported associations between caffeine or coffee consumption and certain diseases. However, certain weak associations with caffeine or coffee intake should be included in the study design when they are known to be risk factors of a disease under investigation. These factors for men are dietary fat intake, vitamin C intake, and body mass index; and for women are vitamin use, alcohol intake, stress, and perceived health status. 相似文献