全文获取类型
收费全文 | 213461篇 |
免费 | 3519篇 |
国内免费 | 539篇 |
专业分类
耳鼻咽喉 | 1842篇 |
儿科学 | 7209篇 |
妇产科学 | 3571篇 |
基础医学 | 23070篇 |
口腔科学 | 2173篇 |
临床医学 | 15410篇 |
内科学 | 38748篇 |
皮肤病学 | 2084篇 |
神经病学 | 19603篇 |
特种医学 | 10969篇 |
外科学 | 33826篇 |
综合类 | 2484篇 |
一般理论 | 7篇 |
预防医学 | 19445篇 |
眼科学 | 3683篇 |
药学 | 12689篇 |
中国医学 | 1137篇 |
肿瘤学 | 19569篇 |
出版年
2023年 | 307篇 |
2022年 | 888篇 |
2021年 | 1433篇 |
2020年 | 765篇 |
2019年 | 1050篇 |
2018年 | 22951篇 |
2017年 | 18199篇 |
2016年 | 20763篇 |
2015年 | 2821篇 |
2014年 | 3009篇 |
2013年 | 3236篇 |
2012年 | 10540篇 |
2011年 | 24308篇 |
2010年 | 20803篇 |
2009年 | 13144篇 |
2008年 | 21824篇 |
2007年 | 23757篇 |
2006年 | 2575篇 |
2005年 | 4001篇 |
2004年 | 4893篇 |
2003年 | 5669篇 |
2002年 | 3660篇 |
2001年 | 913篇 |
2000年 | 1030篇 |
1999年 | 665篇 |
1998年 | 444篇 |
1997年 | 407篇 |
1996年 | 250篇 |
1995年 | 235篇 |
1994年 | 199篇 |
1993年 | 155篇 |
1992年 | 183篇 |
1991年 | 250篇 |
1990年 | 244篇 |
1989年 | 197篇 |
1988年 | 185篇 |
1987年 | 147篇 |
1986年 | 101篇 |
1985年 | 107篇 |
1984年 | 75篇 |
1983年 | 89篇 |
1982年 | 61篇 |
1980年 | 80篇 |
1979年 | 68篇 |
1978年 | 56篇 |
1977年 | 53篇 |
1974年 | 45篇 |
1938年 | 60篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Kentaroh Miyoshi Minoru Naito Tsuyoshi Ueno Shinji Hato Hideo Ino 《General thoracic and cardiovascular surgery》2009,57(11):629-632
A benign esophageal leiomyoma with abnormally increased fluorine-18-fluorodeoxyglucose uptake on positron emission tomography
(PET) was resected thoracoscopically. The tumor, of which the maximum standardized uptake value of the lesion was 4.7, was
well defined and 38 mm in diameter. Neither mitotic activity nor degeneration was found histologically; and immunoreactivity
for CD34, CD117, MIB-1, and glucose transporter-1 was negative immunohistochemically. A diagnosis of gastrointestinal stromal
tumor was ruled out by an oncogenic kinase gene mutation study. This case cautions against PET-dependent evaluation for malignant
potential of esophageal submucosal tumors. 相似文献
32.
33.
BACKGROUND CONTEXT: Spinal manipulation (SM) is a form of manual therapy used clinically to treat patients with low back and neck pain. The most common form of this maneuver is characterized as a high-velocity (duration <150 ms), low-amplitude (segmental translation <2 mm, rotation <4 degrees , and applied force 220-889 N) impulse thrust (high-velocity, low-amplitude spinal manipulation [HVLA-SM]). Clinical skill in applying an HVLA-SM lies in the practitioner's ability to control the duration and magnitude of the load (ie, the rate of loading), the direction in which the load is applied, and the contact point at which the load is applied. Control over its mechanical delivery is presumably related to its clinical effects. Biomechanical changes evoked by an HVLA-SM are thought to have physiological consequences caused, at least in part, by changes in sensory signaling from paraspinal tissues. PURPOSE: If activation of afferent pathways does contribute to the effects of an HVLA-SM, it seems reasonable to anticipate that neural discharge might increase or decrease in a nonlinear fashion as the thrust duration approaches a threshold value. We hypothesized that the relationship between the duration of an impulsive thrust to a vertebra and paraspinal muscle spindle discharge would be nonlinear with an inflection near the duration of an HVLA-SM delivered clinically (<150 ms). In addition, we anticipated that muscle spindle discharge would be more sensitive to larger amplitude thrusts. STUDY DESIGN/SETTING: A neurophysiological study of spinal manipulation using the lumbar spine of a feline model. METHODS: Impulse thrusts (duration: 12.5, 25, 50, 100, 200, and 400 ms; amplitude 1 or 2 mm posterior to anterior) were applied to the spinous process of the L6 vertebra of deeply anesthetized cats while recording single unit activity from dorsal root filaments of muscle spindle afferents innervating the lumbar paraspinal muscles. A feedback motor was used in displacement control mode to deliver the impulse thrusts. The motor's drive arm was securely attached to the L6 spinous process via a forceps. RESULTS: As thrust duration became shorter, the discharge of the lumbar paraspinal muscle spindles increased in a curvilinear fashion. A concave-up inflection occurred near the 100-ms duration eliciting both a higher frequency discharge compared with the longer durations and a substantially faster rate of change as thrust duration was shortened. This pattern was evident in paraspinal afferents with receptive fields both close and far from the midline. Paradoxically, spindle afferents were almost twice as sensitive to the 1-mm compared with the 2-mm amplitude thrust (6.2 vs. 3.3 spikes/s/mm/s). This latter finding may be related to the small versus large signal range properties of muscle spindles. CONCLUSIONS: The results indicate that the duration and amplitude of a spinal manipulation elicit a pattern of discharge from paraspinal muscle spindles different from slower mechanical inputs. Clinically, these parameters may be important determinants of an HVLA-SM's therapeutic benefit. 相似文献
34.
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
35.
36.
37.
38.
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
39.
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
40.