全文获取类型
收费全文 | 157814篇 |
免费 | 11423篇 |
国内免费 | 348篇 |
专业分类
耳鼻咽喉 | 1578篇 |
儿科学 | 4287篇 |
妇产科学 | 3315篇 |
基础医学 | 24481篇 |
口腔科学 | 4181篇 |
临床医学 | 13296篇 |
内科学 | 32199篇 |
皮肤病学 | 2657篇 |
神经病学 | 15653篇 |
特种医学 | 6370篇 |
外国民族医学 | 20篇 |
外科学 | 20273篇 |
综合类 | 779篇 |
现状与发展 | 1篇 |
一般理论 | 162篇 |
预防医学 | 16767篇 |
眼科学 | 3080篇 |
药学 | 9420篇 |
中国医学 | 277篇 |
肿瘤学 | 10789篇 |
出版年
2023年 | 652篇 |
2022年 | 1144篇 |
2021年 | 2450篇 |
2020年 | 1733篇 |
2019年 | 2524篇 |
2018年 | 3169篇 |
2017年 | 2637篇 |
2016年 | 2942篇 |
2015年 | 3254篇 |
2014年 | 4475篇 |
2013年 | 5916篇 |
2012年 | 9043篇 |
2011年 | 9259篇 |
2010年 | 4874篇 |
2009年 | 5002篇 |
2008年 | 8269篇 |
2007年 | 8547篇 |
2006年 | 8130篇 |
2005年 | 7851篇 |
2004年 | 6808篇 |
2003年 | 6527篇 |
2002年 | 5950篇 |
2001年 | 5121篇 |
2000年 | 5049篇 |
1999年 | 4610篇 |
1998年 | 1970篇 |
1997年 | 1698篇 |
1996年 | 1714篇 |
1995年 | 1407篇 |
1994年 | 1277篇 |
1993年 | 1197篇 |
1992年 | 3159篇 |
1991年 | 2879篇 |
1990年 | 2759篇 |
1989年 | 2551篇 |
1988年 | 2371篇 |
1987年 | 2092篇 |
1986年 | 2005篇 |
1985年 | 1921篇 |
1984年 | 1401篇 |
1983年 | 1241篇 |
1982年 | 729篇 |
1981年 | 682篇 |
1980年 | 592篇 |
1979年 | 1068篇 |
1978年 | 680篇 |
1977年 | 601篇 |
1975年 | 555篇 |
1974年 | 595篇 |
1973年 | 607篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Single pre-delivery symphysis-fundal height measurement as a predictor of birthweight and multiple pregnancy 总被引:1,自引:0,他引:1
992.
993.
Randomised trial comparing the upright and supine positions for the second stage of labour 总被引:2,自引:1,他引:1
P. R. de Jong Senior Specialist R. B. Johanson Senior Lecturer P. Baxen Chief Professional Nurse V. D. Adrians Senior Professional Nurse S. van der Westhuisen Lecturer P. W. Jones Professor 《BJOG : an international journal of obstetrics and gynaecology》1997,104(5):567-571
Objective To assess the maternal and neonatal effects of upright compared with recumbent positions during delivery, in terms of defined outcome variables.
Design A randomised controlled trial.
Setting St Monica's Nursing Home, a midwife based maternity unit in Cape Town, South Africa.
Participants Five hundred and seventeen women of low obstetrical risk assigned to deliver at the nursing home.
Results The trial showed that women who adopted the upright posture for delivery experienced less pain, perineal trauma and fewer episiotomies than those who delivered in the supine position.
Conclusion The data suggest that in women of low obstetrical risk, choice of posture during delivery may be encouraged. 相似文献
Design A randomised controlled trial.
Setting St Monica's Nursing Home, a midwife based maternity unit in Cape Town, South Africa.
Participants Five hundred and seventeen women of low obstetrical risk assigned to deliver at the nursing home.
Results The trial showed that women who adopted the upright posture for delivery experienced less pain, perineal trauma and fewer episiotomies than those who delivered in the supine position.
Conclusion The data suggest that in women of low obstetrical risk, choice of posture during delivery may be encouraged. 相似文献
994.
Endoscopic Sphincterotomy and Biliary Drainage in Patients with Cholangitis Due to Common Bile Duct Stones 总被引:13,自引:0,他引:13
995.
996.
Staessen C.; Janssenswillen C.; van Den Abbeel E.; Devroey P.; van Steirteghem A.C. 《Human reproduction (Oxford, England)》1993,8(10):1650-1653
Attempts to increase the probability of a successful pregnancyin in-vitro fertilization (IVF) treatment by increasing thenumber of embryos transferred automatically also increase theprobability of multiple pregnancies and their attendant risks.Even where the number of transferred embryos is limited to amaximum of three as in this and other centres, there is a highincidence of twins and triplets. The question therefore ariseswhether the number of transferred embryos should be furtherlimited to a maximum of two in cases where the prognosis isotherwise good. The only objection to this idea is a possiblelowering of pregnancy rate. The present study set out to investigatethis question. No significant lowering of pregnancy rate wasfound, so that limiting the number of transferred embryos totwo where the prognosis is otherwise good has now become standardpractice in our centre. A good IVF prognosis was defined bythe following criteria: first attempt for IVF, less than 37years old, and good embryo development. From 183 patients fulfillingthese criteria, 80 agreed to the transfer of two embryos (group1) and 103 opted for a triple transfer (group 2). Patient characteristicsand embryology results were similar in the two groups. In group1, 34 patients (42.5%) became pregnant and in group 2, 50 (48.5%).This difference is not significant. Similarly, twin pregnancyrates in both groups were high; eight twin pregnancies (23.5%)in group 1 and 12 (24%) in group 2. For the triplet pregnancyrate of 18% (nine triplet pregnancies) in group 2, there wasobviously no parallel in group 1. After thawing about half ofthe cryopreserved embryos and subsequently replacing them, preliminarycumulative pregnancy rates of 52.5% in group 1 and 53.4% ingroup 2 were obtained. Future results from cryopreservationshould provide relatively better outcomes for group 1 sinceall the patients in this group had at least one embryo frozenand fewer embryos replaced in the fresh cycle. 相似文献
997.
Many different variables have been associated with suicidal behavior as well as with violent behavior. This study was designed to test a model that attempts to relate such variables to violence and suicide risk. Sixty psychiatric patients were evaluated and divided into suicidal and nonsuicidal groups and then into violent and nonviolent groups. Scores on suicide risk, violence risk, anxiety, anger, impulsivity and mood were then compared between these groups. In a second analysis, scores on suicide risk and violence risk were correlated with all the other variables. Anxiety and impulsivity were found to strongly correlate with suicide risk. Angry and resentful mood correlated with violence risk; trait anxiety correlated negatively with violence risk. The results contribute further insight into the authors' two-stage model of countervailing forces. 相似文献
998.
G Liebetrau I M?der D Treutler B Wiesner 《Zeitschrift für die gesamte innere Medizin und ihre Grenzgebiete》1988,43(3):65-67
In 63 out of 887 patients with alveolitis and pulmonary fibroses was causally found a so-called "collagenosis". A participation of the lung in such diseases is prognostically unfavourable. The changes in the framework of the lungs radiographically, functionally and morphologically cannot be separated from fibroses of other origin. The diagnosis is to be made after exclusion of other noxae and taking into consideration the appearances of the primary disease (clinic, spectrum of organs, special laboratory parameters etc.). 相似文献
999.
Course and prognosis of chronic progressive multiple sclerosis: Results of an epidemiological study 总被引:3,自引:0,他引:3
J. M. Minderhoud J. H. van der Hoeven A. J. A. Prange 《Acta neurologica Scandinavica》1988,78(1):10-15
In studies on the natural course of multiple sclerosis (MS), several forms of the disease are distinguished. The most important are the relapsing remitting and the chronic progressive forms. The relationship between these remains unclear. In a prospective epidemiological survey we studied the course of MS using the year in which the chronic-progressive phase started as a landmark. The reliability of this "year of progression" was examined in an observer agreement study. Data were acquired from 342 patients. Progression of the handicap was most rapid in case of a secondary progressive course, female sex, high relapse rate in the preceding remitting phase and "year of progression" at a higher age. Survival after the "year of progression" was lowest in the secondary progressive group. Determining the "year of progression" seems to be significant for the prognosis. 相似文献
1000.
Prospect for enzyme therapy in glycogenosis II variants: a study on cultured muscle cells 总被引:4,自引:0,他引:4
A. T. van der Ploeg P. A. Bolhuis R. A. Wolterman J. W. Visser M. C. B. Loonen H. F. M. Busch A. J. J. Reuser 《Journal of neurology》1988,235(7):392-396
Summary Impairment of skeletal muscle function is the common feature of distinct clinical forms of glycogenosis type II. In the present study, muscle cultures from different patients were used to investigate the cause of clinical heterogeneity and the feasibility of enzyme replacement therapy. The activity of acid -glucosidase appears to be the primary factor in determining the extent of lysosomal glycogen storage in muscle, and thereby the clinical severity of the disease. Neutral -glucosidases do not seem influencial. Correction of the enzymatic defect was achieved in skeletal muscle cultures from patients by administration of a high-uptake form of acid -glucosidase, purified from human urine. The enzyme reaches the lysosomes, including the glycogen storage vacuoles, and the lysosomal glycogen content is reduced to control level. In normal muscle cells 20% of the total cellular glycogen pool is segregated in lysosomal compartments. This percentage is higher than in fibroblasts, which may partly explain why muscles are more prone to store glycogen. The relevance of this study for enzyme therapy is discussed. 相似文献