全文获取类型
收费全文 | 187641篇 |
免费 | 1975篇 |
国内免费 | 38篇 |
专业分类
耳鼻咽喉 | 1289篇 |
儿科学 | 6931篇 |
妇产科学 | 3138篇 |
基础医学 | 17983篇 |
口腔科学 | 1660篇 |
临床医学 | 13787篇 |
内科学 | 33611篇 |
皮肤病学 | 851篇 |
神经病学 | 17520篇 |
特种医学 | 9322篇 |
外科学 | 31231篇 |
综合类 | 2472篇 |
一般理论 | 16篇 |
预防医学 | 18970篇 |
眼科学 | 3008篇 |
药学 | 10154篇 |
中国医学 | 634篇 |
肿瘤学 | 17077篇 |
出版年
2023年 | 181篇 |
2022年 | 373篇 |
2021年 | 794篇 |
2020年 | 394篇 |
2019年 | 604篇 |
2018年 | 22504篇 |
2017年 | 17727篇 |
2016年 | 19886篇 |
2015年 | 1416篇 |
2014年 | 1525篇 |
2013年 | 1540篇 |
2012年 | 8169篇 |
2011年 | 22167篇 |
2010年 | 19383篇 |
2009年 | 11998篇 |
2008年 | 20287篇 |
2007年 | 22418篇 |
2006年 | 1161篇 |
2005年 | 2689篇 |
2004年 | 3822篇 |
2003年 | 4718篇 |
2002年 | 2766篇 |
2001年 | 295篇 |
2000年 | 430篇 |
1999年 | 190篇 |
1998年 | 238篇 |
1997年 | 230篇 |
1996年 | 115篇 |
1995年 | 115篇 |
1994年 | 110篇 |
1993年 | 80篇 |
1992年 | 50篇 |
1991年 | 101篇 |
1990年 | 137篇 |
1989年 | 94篇 |
1988年 | 66篇 |
1987年 | 55篇 |
1986年 | 38篇 |
1985年 | 51篇 |
1984年 | 31篇 |
1983年 | 28篇 |
1982年 | 41篇 |
1980年 | 55篇 |
1978年 | 26篇 |
1969年 | 25篇 |
1938年 | 60篇 |
1937年 | 25篇 |
1934年 | 30篇 |
1932年 | 56篇 |
1930年 | 47篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Statutory reimbursement agencies as well as private insurers throughout member states of the Organization for Economic Cooperation and Development (OECD) reimburse the cost of medicines on the basis of criteria that include robust clinical evidence, budget impact analysis, and incremental cost effectiveness. The Centers for Medicare and Medicaid Services (CMS) in the US are no exception to this rule and are, in principle, seeking to maximize benefit for their Medicare enrollees, whilst ensuring reasonable drug outlays for the small number of drugs that they reimburse. This paper provides a retrospective analysis of the way two functionally equivalent drugs are treated for reimbursement purposes by the CMS; the period under consideration was 2001–3. The two drugs, epoetin-α and darbepoetin-α, are used for the treatment of anemia in renal failure and in patients receiving chemotherapy. By reviewing the publicly available pharmacological and clinical data of epoetin-α and darbepoetin-α, the paper confirms the two drugs’ functional equivalence, despite their structural differences. The implications of dose conversion ratios and costs to Medicare are subsequently explored. It is argued that the issue of dose equivalence between epoetin-α and darbepoetin-α has significant implications for patients, practitioners, and payors. A payor’s perspective is adopted in this respect, whereby clinical evidence and pricing data are used simultaneously. Based on the clinical evidence, a dose conversion ratio for epoetin-α:darbepoetin-α is established, which achieves a comparable clinical effect for the two drugs and this is set to be <254IU:1μg. The incremental costs to Medicare are calculated subsequently. The Average Wholesale Price and the Outpatient Prospective Payment System rule that Medicare uses to reimburse providers are used and suggest that treatment of cancer patients with chemotherapy-related anemia with epoetin-α would save Medicare an estimated $US600 million each year. Patients would also benefit significantly in terms of lower co-payments for epoetin-α. The evidence is supportive of the decision made by the CMS to reimburse the two drugs at the rate reflecting the achievement of comparable clinical effects and therefore reducing the pass-through payments for darbepoetin-α to zero for the 2002–3 fiscal year. 相似文献
62.
Objective: To study the diagnostic value of T2^*-weighted first-pass perfusion imaging in breast tumors. Methods: We analyzed the magnetic resonance imaging (MRI) information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^*-weighted first-pass perfusion imaging. The curve's maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results: Malignant breast lesions showed higher maximal signal intensity drop rate (44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001) than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions (23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05). Conclusion: The T2^*-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis. 相似文献
63.
64.
65.
66.
Chad G. Ball Andrew W. Kirkpatrick Matthew Smith Robert H. Mulloy Leonard Tse Ian B. Anderson 《European journal of trauma and emergency surgery》2007,33(5):550-552
Abstract We report a case of SMV injury in a critically ill patient. The patient was a 19-year-old woman involved in a motor vehicle
collision. Her injuries included grade II splenic and renal lacerations, devascularized and lacerated right and transverse
colon, a transected transverse mesocolon, a massive shear injury of her abdominal wall, and two partial SMV transections.
At initial damage control laparotomy, the SMV was ligated, the devascularized bowel resected and a temporary abdominal closure
applied. At re-operation, a mesocaval shunt using saphenous vein was employed. The shunt failed and the patient required a
saphenous vein jump graft. Although visceral vascular injuries are rare, ligation of the SMV in a damage control situation
is acceptable. This case study is the first to discuss appropriate treatment when interruption to a patient's collateral visceral
venous drainage limits the surgeon’s ability to ligate. In these situations, bypass shunts may be successful. 相似文献
67.
Henry Cisneros 《AIDS and behavior》2007,11(2):7-8
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference. 相似文献
68.
Hoon-Chul Kang Ji Won Kwon Young Mock Lee Heung Dong Kim Hong Jin Lee Si Houn Hahn 《Child's nervous system》2007,23(11):1301-1307
OBJECTIVES: This study sought to characterize epileptic phenotypes in children with nonspecific mitochondrial disease (MD) and to evaluate MD diagnostic approaches. METHODS: A retrospective analysis of the medical, electroencephalogram, and laboratory records of 142 patients with epilepsy was performed. The patients were evaluated for MD, and 124 patients were included in the final cohort. The MD criteria used included an oral glucose lactate stimulation test (OGLST) and urine organic acid/plasma amino acid (UOA/PAA) assays as metabolic indicators of modified Walker criteria, as suggested by Bernier et al. (Neurology 59:1406-1411, 2002). RESULTS: Twenty-two patients were classified as having definite MD (9), probable MD (5), possible MD (6), or pyruvate dehydrogenase (PDH) deficiency (3), including one patient which showed a respiratory chain (RC) defect and PDH deficiency. Seven out of eight patients in whom significant RC defects were observed showed complex I defects. In 14 patients, epileptic seizures start at infantile ages. Of 17 patients who substantially presented generalized seizures, 4 patients started with partial seizures. Five patients consistently presented only partial seizures. The OGLST and UOA/PAA assays were useful for a more precise diagnosis of MD, although low positive predictive value of the OGLST was regrettable. No patient was classified as definite MD by Walker's original criteria, but the use of our revised MD criteria resulted in the classification of nine additional patients as definite MD. CONCLUSIONS: MD manifested considerable diverse epileptic phenotypes and should be considered in the differential diagnosis of epilepsy in children with unexplained encephalomyopathy and progressive and fluctuating clinical courses. 相似文献
69.
70.
Dan Greitz 《Child's nervous system》2007,23(5):487-489
Objective This study aims to question the generally accepted cerebrospinal fluid (CSF) bulk flow theory suggesting that the CSF is exclusively
absorbed by the arachnoid villi and that the cause of hydrocephalus is a CSF absorption deficit. In addition, this study aims
to briefly describe the new hydrodynamic concept of hydrocephalus and the rationale for endoscopic third ventriculostomy (ETV)
in communicating hydrocephalus.
Critique The bulk flow theory has proven incapable of explaining the pivotal mechanisms behind communicating hydrocephalus. Thus, the
theory is unable to explain why the ventricles enlarge, why the CSF pressure remains normal and why some patients improve
after ETV.
Hydrodynamic concept of hydrocephalus Communicating hydrocephalus is caused by decreased intracranial compliance increasing the systolic pressure transmission into
the brain parenchyma. The increased systolic pressure in the brain distends the brain towards the skull and simultaneously
compresses the periventricular region of the brain against the ventricles. The final result is the predominant enlargement
of the ventricles and narrowing of the subarachnoid space. The ETV reduces the increased systolic pressure in the brain simply
by venting ventricular CSF through the stoma. The patent aqueduct in communicating hydrocephalus is too narrow to vent the
CSF sufficiently. 相似文献