全文获取类型
收费全文 | 32236篇 |
免费 | 2429篇 |
国内免费 | 65篇 |
专业分类
耳鼻咽喉 | 208篇 |
儿科学 | 1230篇 |
妇产科学 | 960篇 |
基础医学 | 3811篇 |
口腔科学 | 433篇 |
临床医学 | 5054篇 |
内科学 | 5906篇 |
皮肤病学 | 527篇 |
神经病学 | 3232篇 |
特种医学 | 668篇 |
外国民族医学 | 1篇 |
外科学 | 2961篇 |
综合类 | 505篇 |
一般理论 | 34篇 |
预防医学 | 4647篇 |
眼科学 | 520篇 |
药学 | 1921篇 |
中国医学 | 41篇 |
肿瘤学 | 2071篇 |
出版年
2023年 | 207篇 |
2022年 | 277篇 |
2021年 | 508篇 |
2020年 | 428篇 |
2019年 | 661篇 |
2018年 | 771篇 |
2017年 | 622篇 |
2016年 | 639篇 |
2015年 | 693篇 |
2014年 | 985篇 |
2013年 | 1541篇 |
2012年 | 2324篇 |
2011年 | 2244篇 |
2010年 | 1256篇 |
2009年 | 1182篇 |
2008年 | 1928篇 |
2007年 | 2126篇 |
2006年 | 1959篇 |
2005年 | 2047篇 |
2004年 | 1970篇 |
2003年 | 1793篇 |
2002年 | 1671篇 |
2001年 | 447篇 |
2000年 | 406篇 |
1999年 | 390篇 |
1998年 | 387篇 |
1997年 | 287篇 |
1996年 | 256篇 |
1995年 | 314篇 |
1994年 | 321篇 |
1993年 | 272篇 |
1992年 | 312篇 |
1991年 | 267篇 |
1990年 | 247篇 |
1989年 | 259篇 |
1988年 | 227篇 |
1987年 | 185篇 |
1986年 | 190篇 |
1985年 | 207篇 |
1984年 | 191篇 |
1983年 | 152篇 |
1982年 | 145篇 |
1981年 | 107篇 |
1980年 | 108篇 |
1979年 | 125篇 |
1978年 | 98篇 |
1977年 | 90篇 |
1974年 | 73篇 |
1973年 | 85篇 |
1972年 | 86篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
42.
The role of the anesthesia provider requires a high level of awareness and constant vigilance. Literature indicates, however, that the substance abuse rate in certified registered nurse anesthetists (CRNAs) and anesthesiologists has reached staggering levels. The literature also shows that there has been a change in which controlled drugs are being misused. It is imperative that perianesthesia nurses be aware of the current problem and take steps when indicated to protect both providers and patients. This article discusses the current trends of addiction in anesthesia providers, treatment, and reentry, as well as the role of the perianesthesia nurse in recognizing, reporting, and preventing substance abuse. 相似文献
43.
Marcia C Willing James C Torner Trudy L Burns Kathleen F Janz Teresa A Marshall Julie Gilmore John J Warren Steven M Levy 《Journal of clinical densitometry》2005,8(1):39-47
Four hundred twenty-eight white children (200 boys and 228 girls) ages 4.5-6.5 yr had spine, hip, and whole-body bone mineral density (BMD) and bone mineral content (BMC) measured by dual-energy X-ray absorptiometry(DXA) as part of the Iowa Bone Development Study. Anthropometric measurements, including height, weight, and body mass index (BMI) were determined for each child at the time the bone measurements were made. The age- and gender-specific height percentile based on the 2000 CDC Growth Charts (www.cdc.gov/growthcharts/) was determined for each child. These percentiles were used to classify children into four groups as defined by the 25th, 50th,and 75th percentile cutpoints. Percentile distributions were determined within each height quartile group to delineate percentiles (5th, 25th, 50th, 75th, 95th) for BMD and BMC. Gender differences in BMD and BMC were investigated before and after stratification into height groups. Boys had higher age-height-weight-adjusted means for most BMD and BMC measures except spine BMD. Bone measurements increased with height quartile, indicating that taller children have greater BMD and BMC compared to shorter children of the same age and gender. Within any given quartile,mean BMD and BMC measurements were similar for boys and girls, with the exception of hip BMD, for which values were consistently higher for boys (p < 0.05). In addition, whole-body BMC values were higher for boys in quartiles 1 and 3 (p < 0.05). These bone measures provide norms for young white children and serve as a reference for comparison with other racial and ethnic groups, as well as with childhood populations that are at risk for osteopenia because of chronic disease. Gender, age, and height are useful clinical predictors of BMD and BMC in young children. 相似文献
44.
Karen M Majchrzak Lara B Pupim Kong Chen Cathi J Martin Sheila Gaffney Jane H Greene T Alp Ikizler 《Journal of renal nutrition》2005,15(2):217-224
OBJECTIVE: To determine physical activity patterns in chronic hemodialysis patients with a specific emphasis on the difference between dialysis and nondialysis days. Design A cross-sectional single-center study. SETTING: Vanderbilt University Outpatient Dialysis Unit. PATIENTS: Twenty current chronic hemodialysis patients: 10 male, 10 female; 15 black, 5 white; mean age, 50.1 +/- 9.9 years; height, 164.5 +/- 10.9 cm; weight, 82.5 +/- 15.4 kg; length on dialysis, 57.3 +/- 45.3 months. METHODS: Minute-by-minute physical activity was assessed over a 7-day period using a triaxial accelerometer, which consists of raw numbers or counts calculated by the 3 axes of the accelerometer (PA counts). PA counts were extrapolated on a daily and hourly basis. Physical functioning tests included: sit-to-stand, 6-minute walk, and 1-repetition maximal leg press exercise. Laboratory values for serum concentrations of albumin, prealbumin, C-reactive protein, and cholesterol were also collected. MAIN OUTCOME MEASURE: PA counts. RESULTS: Total PA counts were significantly lower on dialysis days when compared with nondialysis days (128,279 +/- 74,009 versus 168,744 +/- 95,168, respectively, P = .025). The average PA counts during the 4-hour dialysis time period were significantly lower on dialysis days when compared with nondialysis days (3,086 +/- 3,749 versus 11,070 +/- 7,695, respectively, P = .001). At postdialysis hours 1 and 2, PA counts on dialysis days were significantly higher than on nondialysis days (11,410 +/- 5,340 versus 9,082 +/- 6,646, P = .008, and 14,048 +/- 9,728 versus 8,662 +/- 6,433, P = .016, respectively). By postdialysis hour 4, PA counts on dialysis days had significantly decreased when compared with nondialysis days (6,068 +/- 6,268 versus 10,512 +/- 7,420 PA counts, P = .01, respectively). From postdialysis hours 5 to 20, there was no significant difference in PA counts between dialysis and nondialysis days. CONCLUSION: This study shows that physical activity is lower on dialysis days when compared with nondialysis days, and this decrease is caused by the lack of activity during the 4-hour hemodialysis procedure. New behavior modification strategies involving physical activity, both during hemodialysis and on nondialysis days, must be examined in this patient population. 相似文献
45.
46.
47.
P Burns T Wilmink C Fegan A W Bradbury 《European journal of vascular and endovascular surgery》2003,26(2):150-155
BACKGROUND: exercise in IC leads to ischaemia-reperfusion injury of leg muscles and a systemic inflammatory response, but the effect of on coagulation is unknown. OBJECTIVE: to compare the effect of exercise on thrombin formation and fibrin turnover in patients with IC (n = 10), and age and sex matched smokers ([S] n = 5) and non-smokers ([NS] n = 5) without peripheral vascular disease. METHODS: blood was taken from subjects 60 and 30 min before, and 1, 5, 20, 40, 60 and 120 min after, treadmill exercise. Markers of thrombin generation (thrombin-antithrombin complexes [TAT] and prothrombin fragments 1 + 2 [PF1 + 2]) and fibrin turnover (D-dimer and fibrin degradation products [FbDP]) were assayed at each time point. RESULTS: following exercise, thrombin generation was significantly greater in the claudicant group compared to the control groups (Area Under Curve [AUC] post exercise IC vs S vs NS; TAT 3960 vs 1623 vs 1476 vs = 0.007 Kruskal-Wallis [KW]; PF1 + 2 163 vs 107 vs 123 p = 0.024 KW). Pre and post-exercise, fibrin turnover in claudicants was similar to smoking controls, but higher than non-smoking controls. (AUC post exercise IC vs NS; D-dimer 6340 vs 2754 p = 0.055 Mann-Whitney U[MW]; FbDP 45113 vs 21511 p = 0.009 MW). CONCLUSION: when compared to non-claudicants, exercise in IC is associated with excessive production of thrombin. Despite this, claudicants have a similar level of fibrin turnover suggesting a possible defect in fibrinolysis. This prothrombotic state may contribute to the excess thrombotic morbidity and mortality suffered by claudicants. 相似文献
48.
49.
50.
OBJECTIVES: The hypothesis of this study is that calcium homeostasis and bone mineralization are altered in pregnant women receiving long-term therapy with magnesium sulfate as compared with similar women not receiving magnesium sulfate to control preterm labor. STUDY DESIGN: Thirty-nine women between 24 and 32 weeks' gestation, matched for age, race, and duration of bed rest, were enrolled. Indices of calcium homeostasis in serum and urine were measured serially, and bone mineralization of the distal radius was measured at 1 and 11 weeks post partum. RESULTS: Magnesium therapy was administered for a mean duration of 26 +/- 14 days and a cumulative dose of 1405 +/- 963 gm. Serum concentrations of magnesium, phosphorus, and parathyroid hormone increased and those of calcium decreased from baseline values in the magnesium sulfate group and remained uniform throughout the 3-week investigation. The serum magnesium, phosphorus, parathyroid hormone, and calcium concentrations in the control group were unchanged during the study and differed significantly from those in the magnesium sulfate group (p < 0.001). Urinary output of magnesium, calcium, and copper was significantly greater in the magnesium sulfate group than in the control group throughout the study. Urinary losses of calcium in the magnesium sulfate group, approximately 800 to 900 mg/day, were substantial. Although radius bone density 1 week post partum did not differ between groups, the change in bone density from 1 to 11 weeks post partum was significantly lower in the magnesium sulfate group than in controls. CONCLUSIONS: These data suggest that calcium homeostasis is altered during and after long-term magnesium sulfate therapy. The marked, prolonged urinary calcium losses may affect maternal bone mineralization. 相似文献