全文获取类型
收费全文 | 9994篇 |
免费 | 667篇 |
国内免费 | 36篇 |
专业分类
耳鼻咽喉 | 139篇 |
儿科学 | 268篇 |
妇产科学 | 273篇 |
基础医学 | 1464篇 |
口腔科学 | 157篇 |
临床医学 | 1128篇 |
内科学 | 2247篇 |
皮肤病学 | 225篇 |
神经病学 | 1011篇 |
特种医学 | 294篇 |
外科学 | 992篇 |
综合类 | 97篇 |
一般理论 | 2篇 |
预防医学 | 833篇 |
眼科学 | 167篇 |
药学 | 622篇 |
中国医学 | 41篇 |
肿瘤学 | 737篇 |
出版年
2023年 | 105篇 |
2022年 | 212篇 |
2021年 | 399篇 |
2020年 | 271篇 |
2019年 | 284篇 |
2018年 | 329篇 |
2017年 | 246篇 |
2016年 | 311篇 |
2015年 | 351篇 |
2014年 | 394篇 |
2013年 | 555篇 |
2012年 | 786篇 |
2011年 | 805篇 |
2010年 | 460篇 |
2009年 | 409篇 |
2008年 | 629篇 |
2007年 | 576篇 |
2006年 | 564篇 |
2005年 | 524篇 |
2004年 | 437篇 |
2003年 | 389篇 |
2002年 | 371篇 |
2001年 | 86篇 |
2000年 | 76篇 |
1999年 | 59篇 |
1998年 | 82篇 |
1997年 | 52篇 |
1996年 | 43篇 |
1995年 | 46篇 |
1994年 | 36篇 |
1993年 | 30篇 |
1992年 | 43篇 |
1991年 | 38篇 |
1990年 | 39篇 |
1989年 | 39篇 |
1988年 | 43篇 |
1987年 | 43篇 |
1986年 | 34篇 |
1985年 | 41篇 |
1984年 | 32篇 |
1983年 | 38篇 |
1982年 | 39篇 |
1981年 | 15篇 |
1980年 | 18篇 |
1979年 | 24篇 |
1978年 | 27篇 |
1977年 | 18篇 |
1975年 | 17篇 |
1974年 | 15篇 |
1972年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 7 毫秒
11.
K Schleider D Schlamp G E Trott H J Friese G Nissen 《Monatsschrift für Kinderheilkunde》1992,140(5):277-280
The abilities to control the voiding of the bladder and to act competently in dealing with fire are important factors of the normal development of children. Unfavourable conditional constellations in the socio-emotional, cognitive, or physical realm can cause developmental defects which manifest themselves in certain target symptoms, for instance Pyromania and Enuresis. The importance of multifactorial etiological models will be illustrated by a case report of a boy displaying symptoms of Pyromania and Enuresis nocturna. The analysis of the specific conditions of the case studied results in the appropriate multidimensional treatment concept. 相似文献
12.
Cis-dichlorodiamineplatinum(II) (cis-DDP) was encapsulated in reverse phase evaporation vesicles (REV, 0.6 mg cis-DDP/ml lipid solution) and multilayered liposomes (MLV, 0.3 mg cis-DDP/ml lipid solution) with different cholesterol content. The identity of cis-DDP in free and encapsulated form was checked by various techniques. Particle size, homogeneity of liposomes and distribution of cis-DDP in REVs were shown by electron microscopy. The examination of entrapped cis-DDP in REVs relating to buffer and serum stability, in vitro and in vivo antitumour activity and nephrotoxicity proved that all points are strongly influenced by the cholesterol (CH) content. Enclosed cis-DDP in phosphatidyl (PC)-REV has the same, and in PC: CH-REV, a lower effect in vitro and in vivo compared to treatment with the free drug. Irrespective of the application of tumour cells and substance (i.v., i.p.) in optimal therapeutic doses, an equal increase in life-span (ILS) was registered with the free drug and with PC-cis-DDP-REV, while cis-DDP in PC: CH-REV had a significantly reduced effectiveness. Liposomal encapsulation of cis-DDP also influenced body weight change and leucocyte counts. The blood urea nitrogen (BUN) level, as an indicator of renal toxicity, was only moderately increased after very high doses of cis-DDP (24 mg/kg) in PC: CH-REV. 相似文献
13.
Neonatal treatments can disrupt prepulse inhibition (PPI) of startle response later in life. Alpha2A-adrenergic receptors (alpha2A-ARs) regulate the release of brain neurotransmitters that may influence PPI. The authors examined the effects of short-term reduction in the neonatal brainstem alpha2A-ARs on subsequent development of this receptor system and acoustic startle reflex in rats. Administration of antisense oligodeoxynucleotide complementary to the alpha2A-ARs on Days 2-4 of life reduced receptor expression in the brainstem by Day 5. The treatment increased alpha2-AR numbers in the cortex, hippocampus, and amygdala at 40 days of age, and in cortex and hypothalamus at 90 days of age. Transient increases in hippocampal and amygdalar alpha2-ARs were accompanied by attenuation of acoustic startle response and impairment of PPI. 相似文献
14.
Harawa NT Douglas J McFarland W Thiede H Kellogg TA Vorhees K Donovan KM Bingham TA 《Journal of acquired immune deficiency syndromes (1999)》2004,37(1):1206-1215
OBJECTIVES: Using data from anonymous unlinked testing of routinely collected sera, trends in HIV are compared among sexually transmitted disease patients in 4 Western urban centers. METHODS: Between 1989 and 1999, remnant sera obtained for routine syphilis testing from 256,819 patient visits to Denver, Los Angeles, San Francisco, and Seattle clinics were tested for HIV antibodies in an unlinked survey. HIV antibody test results were linked to anonymous demographic and risk information abstracted from the medical record. RESULTS: Overall cumulative HIV seroprevalences among women and among men who had sex exclusively with women were < or = 2%, declined over time, and did not exceed 8% among those who injected drugs. In contrast, cumulative HIV seroprevalences among men who have sex with men ranged from 13% in Seattle to 30% in San Francisco and declined a mean of 2.1% (95% CI, 1.6, 2.6) to 2.8% (CI 2.6, 3.1) per year, after adjustment. CONCLUSIONS: HIV infection declined over time across counties. Relative levels of HIV differed little by demographic and behavioral risk group despite differences in the severity of each county's epidemic. Because of the unique contribution of unlinked serosurveillance studies in monitoring these trends, their reinstitution in high-risk settings should be considered. 相似文献
15.
16.
17.
The exact role and timing of reactivation of telomerase, a key enzyme implicated in cellular immortalization and transformation in the multistep process of laryngeal carcinogenesis, is still unknown. We attempted to (1) determine that quantitative differences exist in the levels of telomerase catalytic subunit (hTERT) mRNA expression among different grades of laryngeal epithelial abnormalities classified according to the Ljubljana classification; (2) determine that telomerase reactivation is an important, most probably early event in laryngeal carcinogenesis; and (3) analyze whether the relative quantity of hTERT mRNA can be used as a molecular biomarker in the early detection of precancerous lesions. The relative quantity of hTERT mRNA, expressed as an hTERT index, was analyzed in 140 frozen laryngeal tissue specimens representing different morphological stages of laryngeal carcinogenesis by using a commercially available LightCycler Telo TAGGG hTERT Quantification kit. The presence and relative quantity of hTERT mRNA in laryngeal epithelium increases progressively with the degree of epithelial abnormalities. hTERT mRNA was detectable in 1/15 normal laryngeal epithelia (7%, mean hTERT index 0.02), 3/15 simple hyperplasias (20%, mean hTERT index 0.09), 10/27 abnormal hyperplasias (37%, mean hTERT index 0.18), 9/12 atypical hyperplasias (75%, mean hTERT index 0.74), 8/9 intraepithelial carcinomas (89%, mean hTERT index 1.82), and 53/62 invasive laryngeal squamous cell carcinomas (85%, mean hTERT index 2.51). Statistical analysis revealed two groups of laryngeal epithelial changes with significant differences in the levels of hTERT mRNA expression (P <.0033): (1) normal and reactive hyperplastic laryngeal epithelium (simple and abnormal hyperplasia) and (2) atypical hyperplasia (precancerous lesion), intraepithelial and invasive laryngeal squamous cell carcinoma. The results of the present study suggest that telomerase reactivation is an early event in laryngeal carcinogenesis, detectable already at the stage of precancerous laryngeal epithelial changes. Nevertheless, other genetic abnormalities appear to be necessary for progression of these epithelial abnormalities toward invasive laryngeal squamous cell carcinoma. 相似文献
18.
C1-esterase inhibitor blocks T lymphocyte proliferation and cytotoxic T lymphocyte generation in vitro 总被引:1,自引:0,他引:1
We have previously shown that activated C1s complement and activated T
cells cleave beta2-microglobulin (beta2m) in vitro leading to the formation
of desLys58 beta2m. This process can specifically be inhibited by
C1-esterase inhibitor (C1-inh). Furthermore we showed that exogenously
added desLys58 beta2m in nanomolar amounts to a one-way allogenic mixed
lymphocyte culture (MLC) increased the endogenous production of IL-2 and
the generation of allo-specific cytotoxic T lymphocytes. C1-inh was
purified from fresh human plasma and added to human or murine MLC and
mitogen-stimulated lymphocyte cultures grown in the presence of
complement-inactivated serum. Read-outs were cell proliferation, lymphokine
production and development of T cell-mediated cytotoxicity. We found that
addition of C1-inh to MLC and mitogen- exposed murine and human lymphocyte
cultures inhibited proliferation, the development of allospecific cytotoxic
activity, and changed the endogenous production of IL-2, IL-4, IL-10, IL-12
and IFN-gamma. These data clearly demonstrate a regulatory function of
C1-inh on T cell- mediated immune functions.
相似文献
19.
Herbal remedies generate more than 1.8 billion dollars in annual sales in the United States. Herbal products have been associated with a wide spectrum of hepatic toxicities. With the recent Women's Health Initiative Study demonstrating increased risk of breast cancer and cardiovascular events associated with hormone therapy, many women may resort to herbal remedies for persistent menopause symptoms. We report a case of autoimmune hepatitis likely triggered by the use of black cohosh (Actaea racemosa), an agent marketed to treat menopause symptoms. Given this case report, we recommend close monitoring of women using this herbal preparation. 相似文献
20.
Voxel-based lesion-symptom mapping 总被引:5,自引:0,他引:5
Bates E Wilson SM Saygin AP Dick F Sereno MI Knight RT Dronkers NF 《Nature neuroscience》2003,6(5):448-450