首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   28208篇
  免费   1401篇
  国内免费   129篇
耳鼻咽喉   523篇
儿科学   1553篇
妇产科学   797篇
基础医学   3175篇
口腔科学   1203篇
临床医学   2566篇
内科学   5126篇
皮肤病学   743篇
神经病学   2501篇
特种医学   1116篇
外国民族医学   4篇
外科学   4856篇
综合类   382篇
一般理论   24篇
预防医学   1640篇
眼科学   637篇
药学   1537篇
  4篇
中国医学   181篇
肿瘤学   1170篇
  2023年   271篇
  2022年   326篇
  2021年   621篇
  2020年   451篇
  2019年   510篇
  2018年   834篇
  2017年   656篇
  2016年   720篇
  2015年   749篇
  2014年   994篇
  2013年   1290篇
  2012年   1769篇
  2011年   1997篇
  2010年   1090篇
  2009年   890篇
  2008年   1496篇
  2007年   1754篇
  2006年   1540篇
  2005年   1687篇
  2004年   1618篇
  2003年   1507篇
  2002年   1356篇
  2001年   736篇
  2000年   817篇
  1999年   578篇
  1998年   238篇
  1997年   190篇
  1996年   147篇
  1995年   126篇
  1994年   102篇
  1993年   98篇
  1992年   220篇
  1991年   193篇
  1990年   179篇
  1989年   137篇
  1988年   162篇
  1987年   144篇
  1986年   128篇
  1985年   114篇
  1984年   101篇
  1983年   75篇
  1982年   64篇
  1979年   97篇
  1978年   80篇
  1975年   61篇
  1974年   72篇
  1973年   81篇
  1972年   57篇
  1971年   68篇
  1970年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Bladder cancer is one of the malignancies encountered frequently in urological practice. Since the three main treatment modalities (surgery, chemotherapy and radiotherapy) may be used alone or together, there are many treatment options. In this paper the current approaches in the treatment of bladder tumours are reviewed and the policy in Marmara University Hospital is described.  相似文献   
72.
OBJECTIVE: To report on the high incidence of anatomical variants of the origin and course of the internal spermatic vein (ISV) discovered at the time of percutaneous embolization of left varicoceles in a pediatric population. METHODS: We reviewed retrospectively the 65 cases of left varicocele treated by percutaneous embolization (grade II and III) in our institution between 1990 and 2000. The course of the left renal vein (LRV), the origin of the ISV, and the number of ISVs and their pathway were recorded in all cases, according to the B?hren classification. RESULTS: In 37/65 (57%), the ISV was single and arose from a normal LRV (type I). The following variants were encountered: type V--circumaortic LRV 9/65 (14%); type IVb--intrarenal origin of ISV 8/65 (12%); type II--multiple ISV 5/65 (8%); and pelvic collaterals 6/65 (9%). CONCLUSION: Venous anatomical variants are frequently encountered (43%) at the time of left varicocele embolization in children. Such variants often impose some adjustments to the technique of embolization and, at times, hamper the procedure.  相似文献   
73.
The volumes of distribution of many acidic drugs have been shown to be close to that of their binding protein, i.e. serum albumin. The distribution of basic drugs mainly bound to alpha 1-acid glycoprotein (AAG) can be questioned with respect to its dependency upon the distribution of this plasma protein. So, a pharmacokinetic study was performed in 7 subjects with human 125I-labelled alpha 1-acid glycoprotein. The steady-state volume of distribution was found to be 5.37 +/- 0.82L. The central volume was 3.23 +/- 0.33L, close to that of plasma volume and the peripheral volume was 2.14 +/- 0.63L. These data allowed the establishment of an equation giving access to the volume of distribution of a basic drug by relating its unbound fraction to physiological distribution of alpha 1-acid glycoprotein. The values yielded by this equation show that the actual and calculated volumes of distribution of basic drugs mainly bound to AAG are discrepant. This protein is thus not the main factor controlling the distribution of basic drugs within the body.  相似文献   
74.
OBJECTIVE: The combination of mifepristone and misoprostol is an established method for induction of early first trimester abortion, but there is no consensus about the best evaluation of treatment outcome. We assessed endometrial thickness, determined by ultrasound and serum-human chorionic gonadotropin (s-hCG) as markers of successful management. METHODS: Prospective trial involving 255 women, with a gestation of 62 days or less, who were to undergo medical abortion. In addition to our established routines of performing clinical and ultrasound examinations, we also determined the s-hCG level prior to treatment and at follow-up. RESULTS: Of the 255 subjects treated during the study, 20 (7.8%) were lost to follow-up. The overall complete abortion rate was 94.0%. Fourteen subjects required vacuum aspiration, nine of them prior to the scheduled follow-up and five thereafter. None of the pregnancies were ongoing. A decrease of 99% in s-hCG levels was noted in 99% of the women, when levels determined prior to mifepristone intake and those measured 15-71 days post-abortion were compared. CONCLUSION: This study confirms that s-hCG levels drop sharply after medical abortion. To assess the completeness of medical abortion, we recommend that clinical examination to be combined with determination of s-hCG. Ultrasonography should be carried out only when indicated.  相似文献   
75.
76.
This report describes the laparoscopic features of two patients with serosal eosinophilic gastroenteritis. In one case only hyperemia of the peritoneal serosa was found. In the other the laparoscopic picture resembled peritoneal carcinomatosis. We show that laparoscopy and peritoneal biopsy may permit diagnosis of the disease without the need for laparotomy.  相似文献   
77.
The liver metabolic response of rats following a standardized intestinal shock, induced by applying a pressure of 120 cm water on the mesenteric vessels for 60 min, was studied. Immediately prior to the release of the pressure on the vessels saline or naloxone was given either as a single injection or as a continuous infusion. After the reperfusion of the intestine no early disturbances in liver metabolism were found as evidenced from the ATP, glucose and lactate levels in liver biopsies taken 15 min following reflow. Within 60 min of reflow reduction of ATP and increases of glucose and lactate levels occurred. There were no major hemodynamic or liver metabolic differences between saline- and naloxone-treated shocked rats. When saline or naloxone was given as a continuous infusion, the changes in liver metabolism were, however, less severe than those observed in the single injection situation pointing toward a non-specific effect of volume replacement rather than a blockade of opioid receptors. Hepatic hypoxia and/or cellular effects of "shock factors" could be mechanisms of pathophysiologic importance for the disturbed liver metabolism in this shock model.  相似文献   
78.
An avidin–biotin enzyme-linked immunosorbent assay (ELISA) is described for h-endorphin (h-EP). Microtiter plates coated with commercially available antibodies were used together with h-EP tracer derivatives that were biotinylated in positions 24, 28, and 29 via a C6 spacer arm. Nonspecific binding of biotinylated derivatives to the microtiter plates was blocked with a mixture of 1% casein and 10% ethanolamine in 0.1 M NaHCO3. A sequential saturation procedure using a high-affinity antiserum in combination with an avidin–alkaline phosphatase complex matched the sensitivity of reported radioimmunoassays (RIAs), with a detection limit of 0.5 fmol/assay. The intra- and interassay coefficients of variation were 5 and 12%, respectively. Results obtained by ELISA and RIA showed good correlations (r = 0.95). The -EP concentration in extracted rat plasma after high-performance liquid chromatographic (HPLC) fractionation was determined by this method to be 1600 fmol/ml.  相似文献   
79.
Effects of muscimol inactivation of the cerebellar nuclei on precision grip   总被引:3,自引:0,他引:3  
A single monkey was trained to perform a grasp, lift, and hold task in which a stationary hand- held object was sometimes subjected to brief, predictable force-pulse perturbations. The displacement, grip, and lifting forces were measured as well the three-dimensional forces and torques to quantify specific motor deficits after reversible inactivation of the cerebellar nuclei. A prior single-cell recording study in the same monkey provided the stereotaxic coordinates used to guide intranuclear injections of muscimol. In total, 34 penetrations were performed at 28 different loci throughout the cerebellar nuclei. On each penetration, two 1.0-microl injections of 5 microg/microl muscimol, were made 1.0 mm apart either within the nuclei or in the white matter just lateral or posterior to the dentate nucleus. Injections in the region corresponding to the anterior interpositus nucleus produced pronounced dynamic tremor and dysmetric movements of the ipsilateral arm when the animal performed unrestrained reaching and grasping movements. In contrast, no relatively short-latency (15-20 min.) deficits were observed after injection in the dentate nucleus, although some effects were observed after several hours. When tested in a primate chair with the forearm supported and restrained at the wrist and elbow, the monkey performed the lift and hold task without tremor or dysmetria. However, with the restraint removed, the forces and torques applied to the manipulandum were poorly controlled and erratic. The monkey's arm was ataxic and a 5-Hz intention tremor was clearly visible. In addition, the animal was generally unable to compensate for the predictable perturbations and the anticipatory grip force increases were absent. However, overall the results suggest that reversible cerebellar nuclear inactivation with muscimol has little effect on isolated distal movements of the wrist and fingers.  相似文献   
80.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号