全文获取类型
收费全文 | 24228篇 |
免费 | 1599篇 |
国内免费 | 282篇 |
专业分类
耳鼻咽喉 | 514篇 |
儿科学 | 327篇 |
妇产科学 | 452篇 |
基础医学 | 4014篇 |
口腔科学 | 420篇 |
临床医学 | 1918篇 |
内科学 | 4544篇 |
皮肤病学 | 952篇 |
神经病学 | 1746篇 |
特种医学 | 1607篇 |
外科学 | 3512篇 |
综合类 | 96篇 |
一般理论 | 1篇 |
预防医学 | 948篇 |
眼科学 | 550篇 |
药学 | 2099篇 |
中国医学 | 335篇 |
肿瘤学 | 2074篇 |
出版年
2023年 | 102篇 |
2022年 | 426篇 |
2021年 | 854篇 |
2020年 | 414篇 |
2019年 | 674篇 |
2018年 | 806篇 |
2017年 | 556篇 |
2016年 | 921篇 |
2015年 | 1242篇 |
2014年 | 1495篇 |
2013年 | 1626篇 |
2012年 | 2399篇 |
2011年 | 2223篇 |
2010年 | 1401篇 |
2009年 | 1144篇 |
2008年 | 1555篇 |
2007年 | 1416篇 |
2006年 | 1164篇 |
2005年 | 1095篇 |
2004年 | 876篇 |
2003年 | 781篇 |
2002年 | 721篇 |
2001年 | 299篇 |
2000年 | 288篇 |
1999年 | 216篇 |
1998年 | 124篇 |
1997年 | 97篇 |
1996年 | 92篇 |
1995年 | 59篇 |
1994年 | 58篇 |
1993年 | 44篇 |
1992年 | 73篇 |
1991年 | 76篇 |
1990年 | 62篇 |
1989年 | 52篇 |
1988年 | 59篇 |
1987年 | 52篇 |
1986年 | 52篇 |
1985年 | 56篇 |
1984年 | 44篇 |
1983年 | 55篇 |
1982年 | 18篇 |
1981年 | 22篇 |
1980年 | 23篇 |
1979年 | 33篇 |
1978年 | 31篇 |
1977年 | 24篇 |
1976年 | 20篇 |
1974年 | 22篇 |
1973年 | 26篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
51.
Mast cell-deficient W/Wv infant mice were similar to normal mice in their susceptibility to and recovery from infection with the intestinal protozoan Cryptosporidium parvum. W/Wv adult mice were significantly more susceptible to primary infection than were normal adult mice, but both groups recovered at a similar rate. 相似文献
52.
The relationship of the extrinsic blood supply to regeneration in graft reconstructed peripheral nerves 总被引:3,自引:0,他引:3
A F Cook H K Moon M P Lynn D Margolin E Z Browne 《British journal of plastic surgery》1988,41(3):298-304
Median nerves of rats were reconstructed with conventional or vascular nerve grafts. After 2, 3 and 4 weeks, Allen Video-Enhanced Contrast, Differential Interference Contrast (AVEC-DIC) microscopy revealed axonal transport in most preparations, with varying degrees of myelination. Radio-isotope tracer was measured in the nerve. Two and 4 week measurements revealed no difference between the graft types. At 3 weeks the vascular graft group exhibited transport along the entire length of the nerve in contrast to a relatively abbreviated path length in the conventional graft group. Nerve conduction velocities (NCV) were measured proximal to, within and distal to the grafts. Three week NCV showed no difference between the graft types. The 4 week NCV revealed normal values in the vascular graft group at points distal to and within the graft. Significant slowing was seen in the conventional grafts at both points. 相似文献
53.
54.
DeokBog Moon SungGyu Lee Shin Hwang KwangMin Park KiHun Kim ChulSoo Ahn YoungJoo Lee TaeYong Ha SeongHun Cho KiBong Oh YeonDae Kim KeonKuk Kim 《Liver transplantation》2004,10(6):802-806
We considered performing living donor liver transplantation (LDLT) in a larger-size recipient. When the recipient was large-sized, or when the donor liver was severely steatotic or had a right-to-left volume discrepancy. We devised dual living donor liver transplantation (DLDLT) to make up for graft size insufficiency and to secure the donor's safety. However, portal vein thrombosis (PVT) presented a challenge for DLDLT because of the need for intact right and left portal veins for the implantation of both liver grafts. Our 52-year-old male patient with hepatitis B cirrhosis had suffered from repeated esophageal and gastric variceal bleeding and underwent 2 trials of a transjugular intrahepatic portosystemic shunt (TIPS). He developed TIPS occlusion and PVT involving the area just above the spleno-mesenteric confluence to the right and left PV. Also, the right PV orifice was destructed and difficult to isolate because of severe periportal inflammation and neointima growth in the TIPS mesh. The patient's two sons were inadequate for donation because of right-to-left volume discrepancy. Therefore, DLDLT using 2 left lobes was necessary to compensate for graft-size insufficiency and to secure donor safety, and we substituted an intact umbilical portion of recipient's left PV for the destroyed right PV. The patient recovered well, and liver function has been normal for more than a year. In conclusion, the umbilical portion of recipient's left PV can be a useful vascular substitute for the reconstruction of a thrombosed main portal branch in DLDLT. 相似文献
55.
Yun Jeong Lim Young-Ho Kim Geung Hwan Ahn Ho Kwung Chun Woo Young Jang Jun Haeng Lee Hee Jung Son Poong-Lyul Rhee Jae J Kim Seung Woon Paik Byung Chul Yoo Jong Chul Rhee 《Taehan Sohwagi Hakhoe chi》2004,44(6):314-320
BACKGROUND/AIMS: Carcinogenesis is characterized by the abnormal regulation of cell cycle. The abnormal expression of the regulators of cell cycle may be related to the prognosis. Since the clinical significance of the expression of the three proteins in colorectal carcinomas is still controversial, we evaluated the prognostic value of the expression of cyclin E, p27 and mutant p53 in stage II colorectal cancer. METHODS: The expression levels of cyclin E, p27 and mutant p53 proteins in 41 patients with stage II colorectal carcinomas were analyzed by immunohistochemistry. RESULTS: In the univariate analysis, the level of CEA at diagnosis was associated with disease relapse. In the multivariate analysis, the clinicopathological variables such as age, gender, site of primary tumor, tumor size, state of tumor differentiation and preoperative plasma CEA level were not associated with disease relapse. When Kaplan-Meier survival curves were constructed to determine the prognosis, cyclin E, p27 and mutant p53 expressions did not predict poor prognosis. CONCLUSIONS: Our results suggested that the expression of cyclin E, p27 and mutant p53 proteins did not predict the clinical outcome in the stage II colorectal carcinomas. 相似文献
56.
PURPOSE: We report an unusual case of vocal cord edema associated with the use of a ProSeal laryngeal mask airway (PLMA) in an adult patient with an undiagnosed upper respiratory tract infection (URTI). CLINICAL FEATURES: A 55-yr-old woman had fixation of a radial fracture under general anesthesia with muscle relaxation. She developed audible wheezing 30 min after PLMA insertion. Bronchoscopic examination revealed significant vocal cord edema. Adequate ventilation was possible at increased airway pressures, and the administration of dexamethasone 4 mg iv produced clinical resolution of the stridor and airway obstruction. The patient admitted to having mild symptoms of an URTI on postoperative questioning. CONCLUSION: Airway hyperreactivity secondary to the URTI is the most likely etiological factor; other possibilities include trauma from insertion and chemical irritation. Although pediatric studies suggest that the LMA-Classic carries less risk than endotracheal intubation in the presence of URTI, this case report demonstrates that caution is still warranted when using supraglottic airways. The PLMA permitted effective ventilation despite increased airway resistance; nevertheless its role in patients with URTI is unclear. It is possible that the bulkier cuff design of the PLMA, compared to that of the LMA-Classic, may have partly contributed to the development of edema in this setting. 相似文献
57.
Kyung‐Sub Moon Shin Jung Jae‐Hyuk Lee Tae‐Young Jung In‐Young Kim Soo‐Han Kim Sam‐Suk Kang 《Neuropathology》2006,26(2):141-146
We present a case of benign osteoblastoma of the occipital bone. Benign osteoblastoma is an uncommon primary bone tumor, which usually involves the vertebrae and the long bones. This tumor rarely develops in the calvaria, showing a preference for the temporal and frontal bones when it does. To the best of our knowledge, this case is only the eighth reported case of benign osteoblastoma confined to the occipital bone. A 20‐year‐old male presented with a mild tender mass lesion of the occipital area, just below the lambda. Plain X‐ray films and CT scans demonstrated an osteolytic mass surrounded by the sclerotic rim within the diploic space. MRI proved to be effective for the evaluation of the intracranial and intraosseous extensions of the tumor. However, it was very difficult to formulate a differential diagnosis against other osteoblastic tumors, or osteoid osteoma, in view of its radiological appearance. The final diagnosis was obtained by careful consideration of the histopathological characteristics of the tumor combined with its clinical and radiological features. Although generally regarded as benign, a complete resection is preferred over conventional curettage as this can guard against possible recurrence and malignant transformation. 相似文献
58.
Seung Min Lee Seung Kyung Hann Soo II Chun Seung Hung Lee Yoon-Kee Park 《The Journal of dermatology》1994,21(2):106-110
A 25-year-old female has had brown to erythematous telangiectatic patches and grouped papules on her face, neck, arm, and trunk since childhood following B.C.G. vaccination. Histopathologically, the lesions consisted of hyperkeratosis, slight acanthosis, tuberculoid granulomas with some Langerhans type giant cells in the mid-dermis. Although various forms of cutaneous tuberculosis after B.C.G. vaccination have been reported, it was difficult for us to assign the patient's skin lesion to any specific disease entity. Remission of her cutaneous lesions occurred clinically and histopathologically after treatment with isoniazid and rifampin. 相似文献
59.
Metabolic consequences of hypercapnia in the rainbow trout, Salmo gairdneri: beta-adrenergic effects
The metabolic consequences of external hypercapnia (1% CO2) were assessed in rainbow trout (Salmo gairdneri) in the presence or absence of circulating levels of the beta adrenoceptor antagonist, propranolol. External hypercapnia caused a severe extracellular respiratory acidosis and a less pronounced reduction of hepatic intracellular pH (pHi). pHi was restored to prehypercapnic values after 48 hr of continuous hypercapnia due to elevation of bicarbonate levels. In the presence of propranolol, hypercapnia elicited a pronounced activation of pyruvate kinase (PyK) (measured at both low and high phosphoenolpyruvate (PEP) concentrations) and inactivation of both total glycogen phosphorylase (GPase) and glycogen phosphorylase a (GPase a). In the absence of propranolol, the changes in enzyme activities were significantly reduced (low PEP PyK activity) or totally absent (GPase inactivation). These results suggest that beta adrenoceptor-mediated phenomena offset disruptive effects of hypercapnia on PyK and GPase activities and may be important in the control of gluconeogenesis and glycogenolysis during this acid-base disturbance. The adrenergic effects were not related to modification of hepatic intracellular acid-base status. Hypercapnia induced a rapid depletion of liver glycogen and concomitant hyperglycemia. These effects were not prevented by pretreating fish with propranolol and appeared to be unrelated to changes in GPase a activity. These results suggest that factors other than adrenergic activation of GPase a are involved in the enhancement of liver glycogenolysis. 相似文献
60.