全文获取类型
收费全文 | 58890篇 |
免费 | 3598篇 |
国内免费 | 269篇 |
专业分类
耳鼻咽喉 | 770篇 |
儿科学 | 2299篇 |
妇产科学 | 1579篇 |
基础医学 | 5638篇 |
口腔科学 | 1632篇 |
临床医学 | 4987篇 |
内科学 | 13149篇 |
皮肤病学 | 1020篇 |
神经病学 | 3336篇 |
特种医学 | 2080篇 |
外国民族医学 | 4篇 |
外科学 | 10657篇 |
综合类 | 1354篇 |
现状与发展 | 3篇 |
一般理论 | 30篇 |
预防医学 | 3706篇 |
眼科学 | 2289篇 |
药学 | 4534篇 |
2篇 | |
中国医学 | 364篇 |
肿瘤学 | 3324篇 |
出版年
2023年 | 591篇 |
2022年 | 1399篇 |
2021年 | 2437篇 |
2020年 | 1402篇 |
2019年 | 1880篇 |
2018年 | 2305篇 |
2017年 | 1653篇 |
2016年 | 1763篇 |
2015年 | 1865篇 |
2014年 | 2508篇 |
2013年 | 3115篇 |
2012年 | 4699篇 |
2011年 | 4427篇 |
2010年 | 2615篇 |
2009年 | 2175篇 |
2008年 | 3332篇 |
2007年 | 3416篇 |
2006年 | 3052篇 |
2005年 | 2742篇 |
2004年 | 2492篇 |
2003年 | 2097篇 |
2002年 | 1831篇 |
2001年 | 878篇 |
2000年 | 846篇 |
1999年 | 714篇 |
1998年 | 374篇 |
1997年 | 286篇 |
1996年 | 271篇 |
1995年 | 230篇 |
1994年 | 212篇 |
1993年 | 172篇 |
1992年 | 444篇 |
1991年 | 424篇 |
1990年 | 358篇 |
1989年 | 343篇 |
1988年 | 291篇 |
1987年 | 284篇 |
1986年 | 249篇 |
1985年 | 292篇 |
1984年 | 230篇 |
1983年 | 196篇 |
1982年 | 125篇 |
1981年 | 131篇 |
1980年 | 110篇 |
1979年 | 171篇 |
1978年 | 131篇 |
1977年 | 101篇 |
1974年 | 112篇 |
1973年 | 147篇 |
1972年 | 126篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Melita Kosanovic Mohammad Yousif Hasan Dhanasekhar Subramanian Abdulla Ali Falah Al Ahbabi Omar Ali Awn Al Kathiri Essa Mohammed Ali Abdulla Aleassa Abdu Adem 《Food and chemical toxicology》2007,45(11):2261-2266
We hypothesized that increased ambient concentrations of metals, as a consequence of escalating urbanization and industrialization of the Gulf region will respond in increased contamination of edible fish species. In this study, we report concentrations of chromium, manganese, cobalt, copper, zinc, arsenic, cadmium, mercury and lead in meat and liver of wild Red-spot emperor (Lethrinus lentjan) from three sampling points at the UAE coast. Analysis was performed by the ICP-MS/microwave digestion. Our study has shown that meat and liver metal content was significantly higher in areas with higher industrial activity, although metal values did not exceed permitted levels of fish for human consumption. 相似文献
103.
104.
Adult male Fisher 344 rats (8-10 wk old) were dosed ip with 1.75 mg/kg body weight of triethyllead chloride (TEL) for 5 consecutive days. Rats were sacrificed 1, 7, or 21 d after the last injection. The rate of lipid peroxidation was significantly elevated in frontal cortex at all three time points assayed (1, 7, or 21 d). However, hippocampal and cerebellar membranes showed no changes in peroxidative capacity at these time points. In order to determine whether cortical membrane damage was reflected in alteration of a restricted protein population, a series of high-affinity receptor binding sites was determined in cortical membranes derived from treated rats 7 d after the last injection of triethyllead. The rate of lipid peroxidation was significantly increased in the frontal cortex of triethyllead treated rats; however, no changes in the binding of [3H]spiroperidol, [3H]quinuclidinyl benzilate, and [3H]benzodiazepine were seen in animals exposed to triethyllead. The cortical wet weight, protein content, and cell number were also unchanged by TEL treatment, reflecting an absence of gross damage. 相似文献
105.
BACKGROUND: Optimal feeding practice in the first year of life is crucial for the survival and health of infants, and has long-term consequences in later life. However, non-optimal feeding practices exist widely. The present study aims to explore various constraints to optimal feeding practices in the first year of life of infants in urban areas of Beijing, China. METHODS: A cross-sectional study was conducted in urban areas of Beijing from 4 July to 20 August, 1998. Two hundred and fifty-one mothers of infants aged 6-12 months were chosen from six child health centers in three different urban districts in Beijing. A self-administered structured questionnaire was used to collect data regarding feeding practices and potentially related factors. RESULTS: Feeding practice for most of the infants was in accordance with the national and international recommendations. However, the rate of incidence of exclusive breast-feeding at 3 months of age was lower than that recommended by the World Health Organisation (WHO) (55.8%), and the introduction of solid/semisolid food before 4 months of age was found in approximately 19.3% of the infants. Cow's milk was given to 21.2% of infants from 6 months of age as the sole source of milk or as a supplement. Maternal education level (OR = 2.44, 95% CI: 1.42-4.19, P < 0.05), employment (OR = 2.05, 95% CI: 1.13-3.74, P < 0.05) and antenatal nonexclusive breast-feeding plans (OR = 4.10, 95% CI: 2.24-7.50, P < 0.001) were found to be correlated to inappropriate feeding practices. CONCLUSIONS: The feeding practices for most of the urban infants was found to be in accordance with the Chinese government and WHO recommendations; however, non-optimal feeding practices presenting as the early cessation of breast-feeding and the introduction of solid/semisolid foods existed. Information regarding optimal feeding practices should be disseminated to mothers and medical professionals in China, to ensure optimal infant health. 相似文献
106.
Background:. Nonablative technologies have been used for fine lines and improvement of skin texture without significant downtime. Nonablative technologies may also be used in combination.
Objective:. To present a brief review on nonablative technologies and discuss using nonablative procedures in combination and with other adjunctive therapies.
Materials and Methods. A review of the literature was done to identify combination nonablative studies. We also discuss our own experience in combining these procedures.
Results. Various nonablative technologies can be used together, often with better outcomes and fewer treatments.
Conclusion:. Nonablative and adjunctive treatments should be performed in combination to optimize the results. Much of the information in this publication is from personal experience and expresses the opinions of these authors while citing relevant literature and studies. 相似文献
Objective:. To present a brief review on nonablative technologies and discuss using nonablative procedures in combination and with other adjunctive therapies.
Materials and Methods. A review of the literature was done to identify combination nonablative studies. We also discuss our own experience in combining these procedures.
Results. Various nonablative technologies can be used together, often with better outcomes and fewer treatments.
Conclusion:. Nonablative and adjunctive treatments should be performed in combination to optimize the results. Much of the information in this publication is from personal experience and expresses the opinions of these authors while citing relevant literature and studies. 相似文献
107.
François Béïque Mohamed Ali Scott MacKenzie Mark Hynes 《Journal canadien d'anesthésie》2007,54(2):158-159
108.
Joseph Cofrancesco Nina Shah Khalil G Ghanem Adrian S Dobs Robert S Klein Kenneth Mayer Paula Schuman David Vlahov Anne M Rompalo 《Gynecological endocrinology》2006,22(5):244-251
Drug use and HIV infection may affect sex hormone levels in women. One hundred and ninety-six women with and without a history of illicit drug use (50 HIV-negative and 148 HIV-infected), with regular menses, who never used antiretrovirals, were evaluated. Luteinizing hormone levels were significantly higher in women with a CD4 cell count <200/microl (p < 0.002). Current methadone use was associated with lower levels of total testosterone (p = 0.03) and higher levels of prolactin (p = 0.002); mean estradiol levels were 43% lower in women who used intravenous drugs (p < 0.001). Alcohol and crack cocaine use was not associated with sex hormone levels. Age, race, body mass index and degree of HIV immunosuppression were also associated with differences in sex hormone levels. 相似文献
109.
Hasan Yüksel Ali Riza Odaba?i Selda Demircan Aslihan Karul Leyla Didem Kozaci Kutsi K?seo?lu Kadir Kizilkaya Okay Ba?ak 《Gynecological endocrinology》2006,22(7):381-387
AIM: To evaluate the effects of oral continuous 17beta-estradiol plus norethisterone acetate (E2/NETA) replacement therapy on abdominal subcutaneous fat, serum leptin level (SLL) and body composition in postmenopausal women. MATERIALS AND METHODS: A 6-month, prospective, randomized, double-blind and placebo-controlled study was conducted. Forty-three healthy naturally postmenopausal women aged 43-65 years were randomly assigned to receive E2/NETA (2 mg E2 plus 1 mg NETA, n = 22) or placebo (n = 21). Fasting SLL by enzyme-linked immunosorbent assay, subcutaneous abdominal fat thickness (STh) by ultrasound and the anthropometric indices of body weight (BW), body mass index (BMI), waist and hip circumference (WC, HC) and waist-to-hip ratio (WHR) were recorded at the beginning and the end of the study. RESULTS: After 6 months of therapy, BW and SLL increased in the placebo group (p = 0.043 and 0.033, respectively). WC, HC and STh decreased significantly in the E2/NETA group (p = 0.002, 0.006 and 0.000, respectively) and they were also significantly lower in women receiving E2/NETA than in women taking placebo (p = 0.000, 0.034 and 0.000, respectively). At baseline, SLL and STh were positively correlated with all anthropometric indices except WHR. CONCLUSION: Oral continuous combined regimen of E2/NETA significantly reduced central fat accumulation as assessed by WC and STh, and attenuated the increase in SLL. The observed changes in SLL were highly and positively related to changes in STh. The oral continuous combined E2/NETA regimen appears to have protective effects on cardiovascular function and probably on metabolic diseases by its slimming effect upon WC in postmenopausal women. 相似文献
110.
Susannah V Quisling Vinay A Shah Ho K Lee Bruno Policeni Wendy R K Smoker Coleman Martin Andrew G Lee 《Journal of neuro-ophthalmology》2006,26(1):47-48
A 44-year-old man with right-sided herpes zoster ophthalmicus (HZO) developed ipsilateral third and sixth cranial nerve palsies and first-division trigeminal (fifth cranial nerve) sensory loss. MRI revealed contrast enhancement of the cisternal and cavernous portions of the third cranial nerve and high signal on a FLAIR sequence within the ipsilateral medulla at the presumed location of the trigeminal nucleus and tract. To our knowledge, this is the first report of the combination of these imaging findings in HZO. 相似文献