全文获取类型
收费全文 | 2373476篇 |
免费 | 196918篇 |
国内免费 | 4204篇 |
专业分类
耳鼻咽喉 | 34280篇 |
儿科学 | 72759篇 |
妇产科学 | 62936篇 |
基础医学 | 334999篇 |
口腔科学 | 67520篇 |
临床医学 | 215590篇 |
内科学 | 468719篇 |
皮肤病学 | 47933篇 |
神经病学 | 200833篇 |
特种医学 | 95975篇 |
外国民族医学 | 886篇 |
外科学 | 360440篇 |
综合类 | 56217篇 |
现状与发展 | 1篇 |
一般理论 | 977篇 |
预防医学 | 190683篇 |
眼科学 | 55464篇 |
药学 | 177601篇 |
4篇 | |
中国医学 | 4365篇 |
肿瘤学 | 126416篇 |
出版年
2018年 | 24228篇 |
2016年 | 20594篇 |
2015年 | 23292篇 |
2014年 | 33563篇 |
2013年 | 50874篇 |
2012年 | 68791篇 |
2011年 | 72325篇 |
2010年 | 42505篇 |
2009年 | 40882篇 |
2008年 | 68790篇 |
2007年 | 73144篇 |
2006年 | 74031篇 |
2005年 | 72072篇 |
2004年 | 69359篇 |
2003年 | 67046篇 |
2002年 | 66287篇 |
2001年 | 112460篇 |
2000年 | 116536篇 |
1999年 | 98348篇 |
1998年 | 27864篇 |
1997年 | 25530篇 |
1996年 | 25455篇 |
1995年 | 24616篇 |
1994年 | 23161篇 |
1993年 | 21559篇 |
1992年 | 79397篇 |
1991年 | 76402篇 |
1990年 | 73579篇 |
1989年 | 70851篇 |
1988年 | 65848篇 |
1987年 | 64801篇 |
1986年 | 61340篇 |
1985年 | 58402篇 |
1984年 | 44224篇 |
1983年 | 37659篇 |
1982年 | 22889篇 |
1981年 | 20334篇 |
1980年 | 19034篇 |
1979年 | 41300篇 |
1978年 | 28987篇 |
1977年 | 24347篇 |
1976年 | 22833篇 |
1975年 | 23965篇 |
1974年 | 29639篇 |
1973年 | 28044篇 |
1972年 | 26229篇 |
1971年 | 24152篇 |
1970年 | 22755篇 |
1969年 | 21087篇 |
1968年 | 19135篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
951.
Association between PCBs and lower embryonic weight in black-crowned night herons in San Francisco Bay 总被引:3,自引:0,他引:3
D J Hoffman B A Rattner C M Bunck A Krynitsky H M Ohlendorf R W Lowe 《Journal of toxicology and environmental health》1986,19(3):383-391
Reproductive problems, including congenital malformations, reduced hatching success, and decreased survival of hatchlings, have been observed in colonial-nesting water birds at the San Francisco Bay National Wildlife Refuge (SFBNWR). Twenty-four black-crowned night heron (Nycticorax nycticorax) eggs were collected from SFBNWR in 1983. Twelve of these were collected from separate nests when late-stage embryos were pipping, and an additional egg was randomly collected from each nest for organochlorine analysis. Overt anomalies and skeletal defects were not apparent. Embryonic weights (with partially absorbed yolk sacs removed) were 15% lower (p less than 0.05) in SFBNWR embryos compared to control embryos from the Patuxent Wildlife Research Center (PWRC). Crown-rump length and femur length were shorter for SFBNWR embryos. The geometric mean polychlorinated biphenyl (PCB) concentration in SFBNWR eggs was 4.1 ppm wet weight, with a range of 0.8-52.0 ppm. A negative correlation (r = -0.61; p less than 0.05) existed between embryonic weight and log-transformed PCB residues in whole eggs collected from the same nest at SFBNWR, suggesting a possible impact of PCBs on embryonic growth. A correlation with embryonic weight did not occur for DDE [1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene] residues. Liver microsomal aryl hydrocarbon hydroxylase activity was neither significantly elevated nor correlated with PCB, DDE, or PCB plus DDE log-transformed residues. It is unknown whether the apparent association between PCBs and lower weight is persistent through hatching. 相似文献
952.
We report a case of vasoactive-agent-induced priapism successfully treated in the emergency department with 10 mg of metaraminol injected into the corpora cavernosa. 相似文献
953.
J T Leke 《The Nursing journal of India》1987,78(8):205-206
954.
Nursing diagnosis as a critical component of the nursing process provides a common taxonomy to describe problems that nurses can treat and is a convenient, logical way to reference nursing standards. Theory is translated into practice with the use of population-specific prototype care guides and a written orders system. Nurses in leadership are responsible for providing the necessary resources to promote professional growth and facilitate desired change. Recommendations to assist with the implementation of nursing diagnosis are identified in Table 1. The system is dependent on staff nurses' professional commitment to learning and willingness to actively participate in change. Involvement of staff nurses continues to be a critical factor in the improvement of nursing practice. 相似文献
955.
956.
P A DeSimone C A Martin C B Bacdayan J S Macdonald F J Rizzo J Engelberg 《Hospital practice (Office ed.)》1986,21(1):158, 160, 165-158, 7 passim
957.
958.
Synthesis of Estradiol Haptens Two estradiol haptens, 4-(3β,17β-dihydroxyestran-7α-yl)butanoic acid ( 9 ) and 7α-(4-aminobutyl)-3β,17β-estradiols ( 13 ), were prepared from 19-nortestosterone by partial synthesis. The binding activity for the cytosol estrogen receptor was determined by competition against [3H]-estradiol; at a concentration of 2×10?7mol/l, compound 9 displaces 50% of [3H]-estradiol. Attached to AH-Sepharose 4B compound 9 allows the cytosol estrogen receptor from calf uterus to be concentrated 1800-fold by affinity chromatography. 相似文献
959.
E B Nelson D R Abernethy D J Greenblatt B Ameer 《British journal of clinical pharmacology》1986,22(1):111-113
Disposition of paracetamol oral elixir was determined in two male patients after administration via feeding jejunostomy and compared with four male controls who received the same dose by mouth. Area under the plasma concentration-time curve, elimination half-life, and time to maximum concentration were similar in both groups after 650 mg paracetamol elixir. The absolute amounts and ratio of paracetamol glucuronide to sulphate, the major urinary metabolites after therapeutic paracetamol doses, were similar after jejunal administration as compared to oral administration. Paracetamol is absorbed and biotransformed in a similar manner after either jejunal or oral administration. Therefore, it may be administered effectively via jejunostomy tube in patients who require this route of administration. 相似文献
960.
Dr. Robert L. Geggel David R. Fulton Harvey L. Chernoff Richard Cleveland Thomas J. Hougen 《Pediatric cardiology》1987,8(4):279-283
Summary An infant girl is described who had cor triatriatum and partial anomalous pulmonary venous connection of the left pulmonary
veins to the coronary sinus, the first report of this combination of lesions. The infant also had a Dandy-Walker malformation
and multiple facial and intrathoracic hemangiomas. The cardiac diagnosis was made by two-dimensional echocardiography. Cardiac
catheterization and angiography confirmed the findings and also demonstrated a persistent left superior vena cava draining
to the coronary sinus. The infant underwent successful surgical repair. Partial anomalous pulmonary venous connection and
left superior vena cava not infrequently are associated with cor triatriatum. Although two-dimensional echocardiography is
sensitive for the detection of cor triatriatum, preoperative cardiac catheterization is necessary to identify unequivocally
systemic and pulmonary venous connections. 相似文献