全文获取类型
收费全文 | 2627篇 |
免费 | 280篇 |
国内免费 | 31篇 |
专业分类
耳鼻咽喉 | 9篇 |
儿科学 | 60篇 |
妇产科学 | 88篇 |
基础医学 | 410篇 |
口腔科学 | 112篇 |
临床医学 | 297篇 |
内科学 | 422篇 |
皮肤病学 | 58篇 |
神经病学 | 217篇 |
特种医学 | 226篇 |
外科学 | 386篇 |
综合类 | 56篇 |
一般理论 | 6篇 |
预防医学 | 265篇 |
眼科学 | 40篇 |
药学 | 142篇 |
1篇 | |
肿瘤学 | 143篇 |
出版年
2023年 | 15篇 |
2022年 | 15篇 |
2021年 | 36篇 |
2020年 | 20篇 |
2019年 | 44篇 |
2018年 | 50篇 |
2017年 | 46篇 |
2016年 | 43篇 |
2015年 | 54篇 |
2014年 | 55篇 |
2013年 | 86篇 |
2012年 | 101篇 |
2011年 | 115篇 |
2010年 | 90篇 |
2009年 | 65篇 |
2008年 | 105篇 |
2007年 | 128篇 |
2006年 | 97篇 |
2005年 | 105篇 |
2004年 | 92篇 |
2003年 | 80篇 |
2002年 | 79篇 |
2001年 | 75篇 |
2000年 | 74篇 |
1999年 | 65篇 |
1998年 | 49篇 |
1997年 | 32篇 |
1996年 | 33篇 |
1995年 | 30篇 |
1994年 | 39篇 |
1993年 | 36篇 |
1992年 | 88篇 |
1991年 | 65篇 |
1990年 | 69篇 |
1989年 | 65篇 |
1988年 | 62篇 |
1987年 | 59篇 |
1986年 | 50篇 |
1985年 | 62篇 |
1984年 | 54篇 |
1983年 | 35篇 |
1982年 | 27篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 33篇 |
1977年 | 14篇 |
1975年 | 21篇 |
1971年 | 20篇 |
1970年 | 14篇 |
1968年 | 13篇 |
排序方式: 共有2938条查询结果,搜索用时 15 毫秒
1.
Neuropharmacology and Drug Interactions in Clinical Practice 总被引:2,自引:2,他引:0
Nina M. Graves 《Epilepsia》1995,36(S2):S27-S33
Summary: Absorption, distribution, and clearance are key pharmacokinetic principles. These parameters can be highly variable among patients and among compounds, and are factors that must be considered in the wide variability in response to medications. Current antiepileptic drugs (AEDs) present many challenges in their administration. However, understanding and utilizing pharmacokinetic principles can assist the clinician in the appropriate optimization of AEds. 相似文献
2.
W. Demark-Wahnefried J. McClelland M. K. Campbell K. Hoben J. Lashley C. Graves B. Motsinger B. K. Rimer 《Journal of the National Medical Association》1998,90(4):197-202
African Americans are at increased risk for cancer and represent an important target population for programs such as Healthy People 2000, the Cancer Information Service (CIS), and the 5 a Day for Better Health Initiative. Yet, awareness of such programs among rural blacks is unknown. This study assessed awareness of these programs and determined related knowledge and beliefs among rural African Americans. It was undertaken as part of the baseline survey for the Black Churches United for Better Health project, a National Cancer Institute-funded initiative. A minority of respondents (n = 3737) demonstrated name recognition of Healthy People 2000 (23.4%), the CIS (42.4%), and the 5 a Day Program (40.7%). Far fewer (7.4%) were able to correctly identify the recommended daily number of servings of fruits and vegetables. Reported family history of cancer was associated with a greater tendency believe that eating more fruits and vegetables can prevent disease. These findings underscore the need for efforts to reach the rural black community with culturally sensitive and stage appropriate cancer prevention messages. Knowledge of family history of cancer may play an important role in targeting subgroups and delivering effective cancer prevention messages. 相似文献
3.
Simultaneous assay of felbamate plus carbamazepine, phenytoin, and their metabolites by liquid chromatography with mobile phase optimization 总被引:1,自引:0,他引:1
Felbamate is an investigational antiepileptic drug (AED) in clinical trials. A high-performance liquid chromatographic method for the simultaneous analysis of felbamate, phenytoin (PHT), 5-(p-hydroxyphenyl)-5-phenylhydantoin, carbamazepine (CBZ), carbamazepine-10,11-epoxide, and carbamazepine-10,11-diol in serum was developed by a mobile phase optimization technique. Capacity factors for the compounds of interest and 12 other AEDs and metabolites were determined with mixtures of methanol, acetonitrile, or tetrahydrofuran and a 0.01 M ammonium phosphate buffer, pH 6.5, on a reversed-phase C8 column. An optimized mobile phase composition was determined that could separate the compounds of interest and three internal standards in less than 15 min. Serum was extracted with CH2Cl2/ethyl acetate (2:1) after addition of three internal standards. The method was validated for within-day and between-day precision and accuracy for the six compounds. Coefficients of variation were generally less than 10% at all concentrations and less than 5% in the typical therapeutic range for each compound. The lower limit of detection was estimated at 0.2 micrograms/ml for CBZ and its metabolites and 0.5 micrograms/ml for felbamate and PHT. For felbamate, the lowest point on the standard curve was 1.88 micrograms/ml with a between-day variability of 10.3%. The assay was used to determine the serum concentrations of PHT and CBZ and its metabolites in a subject before, during, and after felbamate therapy. 相似文献
4.
L Graves D J Stechschulte D C Morris B P Lukert 《Journal of bone and mineral research》1990,5(11):1113-1119
A 59-year-old male presented with systemic mastocytosis with extensive skeletal involvement resulting in vertebral compression fractures and bone pain. Histomorphometric analysis of bone revealed increased mast cells, elevated static parameters of bone resorption, and low bone formation. Serum calcium, phosphorus, and alkaline phosphatase were normal; however, serum 1,25-dihydroxyvitamin D3 and osteocalcin levels were low. Histamine levels in plasma and urine were elevated. Following therapy with ketotifen, the patient had resolution of bone pain along with decreased flushing and pruritus. Elevated plasma and urine histamine levels normalized, as did 1,25-dihydroxyvitamin D3 and osteocalcin levels. Indices of low bone formation improved on therapy. Eroded surfaces improved but remained elevated. This case is the first demonstration that bone symptoms and histomorphometric change in systemic mastocytosis are reversed with inhibition of mast cell degranulation. The role of mast cells and their products in bone metabolism is poorly understood, but the therapy of bone disease in systemic mastocytosis should include inhibition of the release of mast cell products along with the use of histamine antagonist. 相似文献
5.
6.
We describe a modification of the Yang Pros-check radioimmunoassay for prostate-specific antigen (PSA) that increases the analytical sensitivity of the assay approximately threefold (from a working range of 0.3-50 to 0.1-1.2 micrograms/L). It can detect PSA added to zero-concentration diluent (bovine serum albumin solution) at 0.10 microgram/L or added to zero-concentration control female serum at 0.20 microgram/L (P less than 0.05). In 26 patients tested after cystoprostatectomy for bladder cancer (who had normal prostates without cancer on histologic examination), PSA values by this ultrasensitive assay were all less than 0.10 microgram/L. Therefore, we propose this value as the upper limit of the 95% reference interval. In a retrospective study of two patients who developed recurrent prostate cancer, serum PSA values increased above the 0.1 microgram/L detection limit 175 and 581 days before increasing above the 0.3 microgram/L detection limit of the standard Yang assay. This ultrasensitive radioimmunoassay of PSA should prove more useful than current methods for detecting early recurrence of prostate cancer. 相似文献
7.
8.
R R Mehta L Valcourt J Graves R Green T K Das Gupta 《International journal of cancer. Journal international du cancer》1987,40(3):305-308
Total and subcellular (cytosol and nuclear) concentrations of estrone (E1), estradiol (E2), and androstenedione were determined in non-malignant (n = 61) and malignant (n = 65) human breast tissues obtained from post-menopausal women. The 17 beta-hydroxysteroid dehydrogenase (17 beta-OH-SDH) activity was determined in 800g supernatant fraction. Total estrogens, E1 and E2 levels and 17 beta-OH-SDH activity were significantly (p less than 0.005, 0.0005, 0.001, respectively) higher in malignant than in non-malignant breast tissues. We failed to observe significant changes in subcellular steroid concentrations or enzyme activity associated with patients' obesity or tumor estrogen receptor status. When the steroid levels were analyzed in relation to clinical staging of the disease, nuclear contents of estradiol were significantly higher (p less than 0.005) in Stage-IV patients than in those with less advanced disease (Stages I to III). 17 beta-OH-SDH activity was significantly (p less than 0.001) lower in patients with advanced disease than in those with relatively less advanced (Stages I to III) disease and was positively correlated with tissue concentration of androstenedione. Our present data indicate that differential intracellular metabolism of steroid hormones may have some influence on availability of estradiol at nuclear sites. In postmenopausal women, local interconversion of estrogens may provide sufficient estrogenic stimulus to enhance the growth and progression of breast tumors. 相似文献
9.
Patricia Aikins Murphy Jane Mashburn Barbara W. Graves Mickey Gillmor-Kahn 《Journal of Midwifery & Women's Health》1992,37(6):404-410
This article reviews the normal hematologic changes in pregnancy and the kinetics of iron metabolism. The differences between iron depletion and anemia are described. The hematocrit levels of a nurse-midwifery caseload in a tertiary-care setting are described and compared with recently published population norms. Hematocrits of the sample compared favorably to the population hematocrits until 24 weeks' gestation, when the sample hematocrit mean became statistically lower and remained that way throughout pregnancy. Further analysis was done on the sample hematocrits, comparing differences in parity, age, pregnancy spacing, and AS versus AA hemoglobin. Parous women with a pregnancy interval >12 months had a higher mean hematocrit then nulliparous women. Mean hematocrits of age groups varied significantly only at the 29–32-week interval, with women younger than 18 having lower mean hematocrits than those ≥18. A trend of women with AS hemoglobin having higher hematocrits than women with AA hemoglobin was identified, reaching statistical significance at the 29–32-week interval. 相似文献
10.
Anulus fibrosus in bulging intervertebral disks 总被引:1,自引:0,他引:1
In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks. 相似文献